Radiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Peterson, M. S.
Right arrow Articles by Hunt, L. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Peterson, M. S.
Right arrow Articles by Hunt, L. E.
(Radiology. 2000;217:743-749.)
© RSNA, 2000


Gastrointestinal Imaging

Pretransplantation Surveillance for Possible Hepatocellular Carcinoma in Patients with Cirrhosis: Epidemiology and CT-based Tumor Detection Rate in 430 Cases with Surgical Pathologic Correlation1

Mark S. Peterson, MD, Richard L. Baron, MD, J. Wallis Marsh, Jr, MD, James H. Oliver, III, MD, Sharmen R. Confer, BS and LaVerne E. Hunt, BS

1 From the Departments of Radiology (M.S.P., R.L.B., J.H.O., S.R.C., L.E.H.) and Surgery (J.W.M.), University of Pittsburgh School of Medicine, 200 Lothrop St, Pittsburgh, PA 15213-2582. From the 1996 RSNA scientific assembly. Received January 28, 2000; revision requested March 15; revision received May 5; accepted May 22. Address correspondence to M.S.P. (e-mail: petersonms@radserv.arad.upmc.edu).


    ABSTRACT
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
PURPOSE: To determine the prevalence of clinically unsuspected hepatocellular carcinoma (HCC) with advanced cirrhosis and assess the sensitivity of helical computed tomographic (CT) surveillance for tumor detection in these patients.

MATERIALS AND METHODS: Prospective direct correlation of CT findings with explanted liver specimen findings was performed in 430 transplant recipients with cirrhosis. The prevalence of clinically unsuspected HCC according to liver disease cause was evaluated. Serum {alpha}-fetoprotein (AFP) values in patients with and those without tumor were recorded. Prospective and retrospective CT tumor detection was evaluated with respect to CT technique and time from CT to transplantation.

RESULTS: HCC was found in 59 (14%) of 430 transplant recipients without suspicion of tumor before referral for transplantation. HCC was most prevalent with hepatitis B (27%) and hepatitis C (22%). Serum AFP values were not sensitive for detection of most small tumors. With triphasic helical CT, the prospective and retrospective rates of identifying patients with tumor were 59% and 68%, respectively; the prospective and retrospective tumor nodule detection rates were 37% and 44%, respectively. Tumor detection rates were highest with CT performed within 67 days before transplantation.

CONCLUSION: Clinically unsuspected HCC is most prevalent with cirrhosis secondary to hepatitis B or C, and, when evaluated at CT, is best detected with triphasic contrast material–enhanced helical imaging performed within 67 days before transplantation.

Index terms: Liver, cirrhosis, 761.288, 761.794 • Liver, CT, 761.12111, 761.12112, 761.12114, 761.12115 • Liver, transplantation, 761.459 • Liver neoplasms, 761.323 • Liver neoplasms, CT, 761.12111, 761.12112, 761.12114, 761.12115


    INTRODUCTION
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
The most common primary hepatic malignancy and most common intraabdominal malignancy in the world, hepatocellular carcinoma (HCC), is increasing in incidence in the United States (1). HCC usually occurs as a complication of chronic liver disease and most often arises within a cirrhotic liver (15). The accurate diagnosis of HCC with cirrhosis is important for patient care and treatment decisions. Small tumors may be amenable to surgical resection (68), percutaneous alcohol ablation, or radio-frequency ablation, whereas larger unresectable tumors may be treated with transcatheter chemoembolization (9) or systemic chemotherapy. In Western countries, liver transplantation is becoming a treatment of choice for early-stage HCC that is unresectable because of advanced cirrhosis (10).

Although the examination of patients with cirrhosis for possible HCC includes thorough clinical, laboratory, and imaging examinations, some patients who undergo transplantation are nonetheless found at pathologic evaluation of explanted native livers to have harbored unsuspected or undiagnosed tumors (11). Accurate preoperative surveillance of transplantation candidates with cirrhosis for unsuspected HCC is important not only to diagnose and correctly stage the tumor so that the appropriate treatment can be offered (12) but also to prevent ineffective transplantation in patients with advanced disease (13). This is particularly important in light of the limited supply of donor livers relative to the large number of patients awaiting transplantation.

Given the length of many transplantation waiting lists, it is important to identify small tumors so that appropriate treatment can be offered or consideration can be given to moving a patient to a higher position on the waiting list. These measures are important to help prevent progression of a small treatable tumor to advanced-stage disease. Furthermore, it is not uncommon to find that unsuspected HCC diagnosed after transplantation is multifocal or bilobar advanced-stage intrahepatic disease that necessitates adjuvant chemotherapy after transplantation. The immunosuppressed state of transplant recipients may adversely affect patient tolerance to chemotherapy and chemotherapy efficacy (14).

Although computed tomographic (CT) scanning is a commonly used conventional technique for pretransplantation imaging evaluation of patients with cirrhosis, the actual sensitivity of CT surveillance for detection of clinically unsuspected HCC tumor may vary according to several factors, including scanning technique, tumor size, and interval from scanning to transplantation. We undertook this study of the prospective direct correlation of pretransplantation CT findings with surgical pathologic findings of explanted livers to assess the sensitivity of helical CT for tumor detection and determine the relative prevalence of unsuspected HCC according to various causes of cirrhosis.


    MATERIALS AND METHODS
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Patients
All patients with advanced liver disease and no clinical suspicion of HCC who were referred to and seen at our institution between July 1, 1993, and December 31, 1995, for evaluation for possible liver transplantation underwent one or more CT examinations before transplantation. Pretransplantation CT is a part of the routine examination of transplantation candidates at our institution. Of the 1,329 patients who underwent transplantation evaluation during this period, 430 patients with cirrhosis underwent transplantation up to August 1, 1997, the date of closure for this study. Approval for prospective imaging-pathologic correlation of pretransplantation imaging studies with explanted liver specimen findings in all patients who underwent liver transplantation during this period was obtained from the institutional review board of our medical center.

Patients who received transplants for acute fulminant hepatitis or other causes of liver disease without cirrhosis were not included in the study population. Prospective correlation of the surgical pathologic findings with the preoperative CT findings was performed in all 430 transplant recipients. The 430 patients who comprised the study population included 248 male and 182 female patients (mean age, 54 years; age range, 17–73 years). HCC was diagnosed at surgical pathologic evaluation of explanted livers in 59 patients (41 men, 18 women; mean age, 57 years; age range, 28–69 years). Clinical records were reviewed to document the cause of liver disease in each patient and to ensure that no tumor had been clinically suspected or diagnosed before referral for transplantation. Serum {alpha}-fetoprotein (AFP) values were available in 406 of the 430 transplant recipients, including 58 of the 59 patients with HCC. Mean AFP levels were determined in the subsets of transplant recipients with and without HCC. The time from last CT examination to transplantation in each patient also was determined.

CT Technique
All patients underwent an initial CT examination, and most were followed up with additional examinations until transplantation. Because not every patient who underwent clinical evaluation underwent transplantation, the prospective data entry was performed at the time of gross pathologic evaluation of the explanted livers after transplantation. The availability of donor livers could not be predicted; thus, the time of CT relative to the time of transplantation was not controlled. Early in the study period, some patients underwent CT performed with nonhelical scanners. These patients were included in the database to allow assessment of the prevalence of HCC at transplantation in the entire surveillance population. Because multiple CT scanners were used, no one date when all the patients in the surveillance population would have undergone helical CT could be selected. The majority of patients underwent CT performed by using a helical technique with a current-model scanner (HiSpeed Advantage; GE Medical Systems, Milwaukee, Wis).

CT scans were obtained, when possible, with a triphasic technique (15), which included the acquisition of nonenhanced images of the liver followed by the acquisition of images with intravenous contrast material–enhanced biphasic helical CT during the hepatic arterial and portal venous phases of enhancement. Section collimation was 7 mm with a pitch of 1.5:1.0. Scanning delays were 20–28 seconds for hepatic arterial phase imaging and 60–70 seconds for portal venous phase imaging. The contrast-enhanced images were obtained with 150 mL of iodinated contrast material (iothalamate meglumine injection 60% [Conray] or ioversol injection 68% [Optiray 320]; Mallinckrodt, St Louis, Mo), which was administered intravenously with a mechanical power injector (Medrad, Pittsburgh, Pa) at a rate of 2.5–5.0 mL/sec.

Although most of the patients underwent biphasic CT scanning with contrast material injection rates of 4–5 mL/sec, early in our experience with biphasic CT, before we were aware of the effectiveness of higher contrast material injection rates in increasing the conspicuity of vascular tumors, some patients received contrast material injected at a rate of 2.5 mL/sec. The rates of contrast material injection were not recorded in our medical records, so we cannot determine how many patients were administered contrast material at the lower rate of 2.5 mL/sec.

Of the 430 patients, 320 underwent CT with the triphasic technique, 92 underwent nonenhanced and portal venous phase CT, and 18 underwent only nonenhanced CT. Those patients who underwent nonenhanced and portal venous phase CT rather than triphasic CT usually had poor venous access that precluded the intravenous injection of contrast material at the higher rate necessary for triphasic imaging or underwent imaging with a nonhelical scanner. Those patients who underwent only nonenhanced CT had renal insufficiency or other contraindications to contrast material administration.

CT Scan Interpretation
The CT diagnoses of liver lesions were evaluated in two ways. The prospective original clinical reports on the CT scans rendered by experienced radiologists with subspecialty expertise in abdominal imaging at the time of the examinations were used for primary data analysis of CT tumor detection. The CT scans that showed lesions that were considered to be diagnostic of or highly suspicious for HCC according to the original clinical report were considered to be positive. The lesions considered to be positive for tumor also included those that were described by the readers of the CT scans as enhancing lesions with characteristics not typical of hemangiomas and as hypovascular masses not characteristic of cysts or hemangiomas. Conversely, the CT scans that were reported to be equivocal or negative for tumor were considered to be negative. In the patients who underwent multiple CT examinations, the CT results were considered to be positive when any scan was positive.

Given the large number of patients and CT scans and the clinical interpretation of the CT scans by a number of abdominal imaging subspecialist radiologists, data based on prospective specific diagnostic criteria for HCC diagnosis were not collected.

To prospectively correlate the imaging findings with the surgical pathologic findings (described in next section), all of the CT scans were also retrospectively reviewed at the time of specimen sectioning. Any tumor detected at pathologic analysis that was not reported in the clinical CT reports was recorded. The tumors not initially reported that were retrospectively detectable at CT after surgical pathologic correlation were subsequently confirmed by means of agreement between two investigators.

Imaging-Pathologic Correlation
Within 24 hours after transplantation, at surgical pathologic gross-specimen evaluation, the explanted livers were cut into 8–10-mm-thick sections that matched as closely as possible the transverse orientation of the CT images. The preoperative CT findings were prospectively and directly correlated with the surgical pathologic findings by an investigator experienced in abdominal imaging who was present during specimen sectioning. The number, size, and location of all lesions suspicious for HCC at specimen sectioning were recorded prospectively. The specimens were also carefully examined to identify any lesions seen on the preoperative CT scan that were suspicious for tumor. If a lesion seen at preoperative CT was not found in the initial specimen sections, additional thinner sections in additional planes were made to improve correlation between the imaging and pathologic findings. Specimen section maps were recorded to correlate the imaging and pathologic findings. Lesion specimen pathologic section numbers also were recorded for subsequent direct histologic correlation with specific CT findings.


    RESULTS
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Liver Disease Causes and HCC Prevalence
The causes of liver disease in the 430 transplant recipients and the prevalence of HCC according to liver disease diagnosis are presented in Table 1. Unsuspected HCC was most prevalent in patients with hepatitis B, hepatitis C, a combination of hepatitis B and C, and a combination of alcohol-related liver disease and hepatitis C. No HCC tumor was diagnosed at surgical pathologic analysis in 29 patients with primary sclerosing cholangitis, five of whom, however, had cholangiocarcinoma. Four of these five cases of cholangiocarcinoma were diagnosed as hypovascular masses at CT in the original clinical report. One small cholangiocarcinoma of the common hepatic duct was not visible at CT and was diagnosed only at pathologic evaluation of the explanted liver.


View this table:
[in this window]
[in a new window]

 
TABLE 1. Causes of Liver Disease and Prevalence of HCC in Transplant Recipients with Cirrhosis
 
One hundred five HCC tumor nodules were detected at surgical pathologic analysis of the livers explanted from 59 (14%) patients. Of these 59 patients with tumors, 41 (70%) had one tumor nodule, five (8%) had two tumor nodules, eight (14%) had three tumor nodules, and five (8%) had four or more tumor nodules. As measured at surgical pathologic evaluation, the tumor nodules ranged in size from 2 to 60 mm.

AFP Levels
  The reference range for normal serum AFP values at our clinical laboratory is 0–20 µg/L. The mean serum AFP level in 348 patients without HCC was 8 µg/L (range, 1–166 µg/L; median, 4 µg/L). The mean serum AFP level in 58 patients with HCC was 48 µg/L (range, 0–1,378 µg/L; median, 5 µg/L). When two patients with HCC and outlier AFP values of 776 and 1,378 µg/L were excluded from consideration, the mean serum AFP level in the remaining 56 patients with tumor was 11 µg/L (range, 0–87 µg/L; median, 5 µg/L). The elevated AFP values in these two patients were first detected after the patients had been referred to our institution, without clinical suspicion of tumor, for liver transplantation evaluation, which included CT scanning. Triphasic helical CT in these two patients depicted small (<3-cm) solitary tumors, which were confirmed at subsequent pathologic analysis.

HCC Detection at CT
  Of 59 patients with HCC, 44 (75%) underwent triphasic helical CT; 11 (19%), nonenhanced and portal venous phase CT; and four (7%), only nonenhanced CT prior to transplantation. Prospectively, CT with all techniques depicted tumor in 26 (44%) patients with HCC (Fig 1). At retrospective review, tumor was detectable by using CT in 31 (52%) patients with HCC (Fig 2). When only triphasic helical CT was considered, however, prospective tumor detection was increased to 59% (26 of 44 patients) and retrospective tumor detection was increased to 68% (30 of 44 patients). Prospective and retrospective HCC tumor detection rates at CT are presented in Table 2.



View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 1a. Hepatitis C, alcohol-related liver disease, and HCC that was prospectively diagnosed at triphasic contrast-enhanced helical CT in a 45-year-old man. (a) Transverse nonenhanced CT image shows nodular cirrhotic liver without an identifiable mass; a small HCC tumor is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase CT image shows a small hypervascular HCC tumor (arrow). (c) Transverse portal venous phase CT image fails to depict the tumor seen in b. (d) Gross pathologic liver specimen obtained 40 days after CT confirms the presence of a 20-mm, moderately differentiated HCC tumor (arrow).

 


View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 1b. Hepatitis C, alcohol-related liver disease, and HCC that was prospectively diagnosed at triphasic contrast-enhanced helical CT in a 45-year-old man. (a) Transverse nonenhanced CT image shows nodular cirrhotic liver without an identifiable mass; a small HCC tumor is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase CT image shows a small hypervascular HCC tumor (arrow). (c) Transverse portal venous phase CT image fails to depict the tumor seen in b. (d) Gross pathologic liver specimen obtained 40 days after CT confirms the presence of a 20-mm, moderately differentiated HCC tumor (arrow).

 


View larger version (143K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 1c. Hepatitis C, alcohol-related liver disease, and HCC that was prospectively diagnosed at triphasic contrast-enhanced helical CT in a 45-year-old man. (a) Transverse nonenhanced CT image shows nodular cirrhotic liver without an identifiable mass; a small HCC tumor is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase CT image shows a small hypervascular HCC tumor (arrow). (c) Transverse portal venous phase CT image fails to depict the tumor seen in b. (d) Gross pathologic liver specimen obtained 40 days after CT confirms the presence of a 20-mm, moderately differentiated HCC tumor (arrow).

 


View larger version (120K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 1d. Hepatitis C, alcohol-related liver disease, and HCC that was prospectively diagnosed at triphasic contrast-enhanced helical CT in a 45-year-old man. (a) Transverse nonenhanced CT image shows nodular cirrhotic liver without an identifiable mass; a small HCC tumor is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase CT image shows a small hypervascular HCC tumor (arrow). (c) Transverse portal venous phase CT image fails to depict the tumor seen in b. (d) Gross pathologic liver specimen obtained 40 days after CT confirms the presence of a 20-mm, moderately differentiated HCC tumor (arrow).

 


View larger version (162K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 2a. Hepatitis C and HCC that was not prospectively diagnosed at triphasic contrast-enhanced helical CT in a 57-year-old man. (a) Transverse nonenhanced CT image shows cirrhotic liver without an identifiable mass; an HCC tumor adjacent to the inferior vena cava is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase helical CT image that was initially interpreted as not showing tumor retrospectively shows a 25-mm hypervascular HCC tumor (black arrow) adjacent and immediately posterior to the inferior vena cava (white arrows). (c) Transverse portal venous phase helical CT image shows an HCC tumor (arrow) that is hypoattenuating relative to the surrounding liver parenchyma. (d) Gross pathologic liver specimen confirms the presence of a 50-mm, moderately differentiated HCC tumor (arrow). In the 339-day interval between CT and transplantation, the tumor increased from 25 to 50 mm.

 


View larger version (162K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 2b. Hepatitis C and HCC that was not prospectively diagnosed at triphasic contrast-enhanced helical CT in a 57-year-old man. (a) Transverse nonenhanced CT image shows cirrhotic liver without an identifiable mass; an HCC tumor adjacent to the inferior vena cava is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase helical CT image that was initially interpreted as not showing tumor retrospectively shows a 25-mm hypervascular HCC tumor (black arrow) adjacent and immediately posterior to the inferior vena cava (white arrows). (c) Transverse portal venous phase helical CT image shows an HCC tumor (arrow) that is hypoattenuating relative to the surrounding liver parenchyma. (d) Gross pathologic liver specimen confirms the presence of a 50-mm, moderately differentiated HCC tumor (arrow). In the 339-day interval between CT and transplantation, the tumor increased from 25 to 50 mm.

 


View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 2c. Hepatitis C and HCC that was not prospectively diagnosed at triphasic contrast-enhanced helical CT in a 57-year-old man. (a) Transverse nonenhanced CT image shows cirrhotic liver without an identifiable mass; an HCC tumor adjacent to the inferior vena cava is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase helical CT image that was initially interpreted as not showing tumor retrospectively shows a 25-mm hypervascular HCC tumor (black arrow) adjacent and immediately posterior to the inferior vena cava (white arrows). (c) Transverse portal venous phase helical CT image shows an HCC tumor (arrow) that is hypoattenuating relative to the surrounding liver parenchyma. (d) Gross pathologic liver specimen confirms the presence of a 50-mm, moderately differentiated HCC tumor (arrow). In the 339-day interval between CT and transplantation, the tumor increased from 25 to 50 mm.

 


View larger version (127K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 2d. Hepatitis C and HCC that was not prospectively diagnosed at triphasic contrast-enhanced helical CT in a 57-year-old man. (a) Transverse nonenhanced CT image shows cirrhotic liver without an identifiable mass; an HCC tumor adjacent to the inferior vena cava is isoattenuating relative to the surrounding liver parenchyma. (b) Transverse arterial phase helical CT image that was initially interpreted as not showing tumor retrospectively shows a 25-mm hypervascular HCC tumor (black arrow) adjacent and immediately posterior to the inferior vena cava (white arrows). (c) Transverse portal venous phase helical CT image shows an HCC tumor (arrow) that is hypoattenuating relative to the surrounding liver parenchyma. (d) Gross pathologic liver specimen confirms the presence of a 50-mm, moderately differentiated HCC tumor (arrow). In the 339-day interval between CT and transplantation, the tumor increased from 25 to 50 mm.

 

View this table:
[in this window]
[in a new window]

 
TABLE 2. HCC Detection according to CT Phase
 
The cases of HCC tumor diagnosed at retrospective review of CT scans that were correlated directly with the surgical pathologic findings included four patients who underwent triphasic helical CT and one patient who underwent nonenhanced and portal venous phase CT. All five cases represented instances of initially false-negative CT scan interpretation, including a case of an enhancing hypervascular tumor that was initially misinterpreted as an adjacent vascular structure (Fig 2). In addition, two other patients had small subtle arterial phase hypervascular tumors, one had a subtle hypoattenuating tumor, and one had a calcified tumor nodule that was initially interpreted to be of indeterminate cause.

Of 105 tumor nodules detected at pathologic analysis, 30 (29%) were detected prospectively at CT and 37 (35%) were detectable retrospectively at CT. When only triphasic helical CT was considered, however, prospective tumor nodule detection increased to 37% (30 of 82 tumor nodules found at pathologic analysis) and retrospective tumor nodule detection increased to 44% (36 of 82 tumor nodules). The 37 tumor nodules that were detectable retrospectively at CT ranged in size at surgical pathologic analysis from 9 to 60 mm (mean, 24 mm), whereas the 68 tumor nodules that were not detected at CT and found only at surgical pathologic analysis ranged in size from 2 to 40 mm (mean, 13 mm).

The mean time from the last CT examination to transplantation in the 59 patients with HCC was 107 days (median, 49 days; range, 1–671 days). The HCC detection rates according to time from last CT examination to transplantation are presented in Table 3. Note that no tumor was prospectively detected by using CT in any patient whose scan was obtained more than 180 days before transplantation. CT tumor detection was highest in patients who underwent scanning within 67 days before transplantation.


View this table:
[in this window]
[in a new window]

 
TABLE 3. HCC Detection according to Time from Last CT Examination to Transplantation
 
Portal vein thrombus was found at pathologic analysis in only two of 59 patients with HCC. In neither case, however, did portal vein thrombus affect CT scan interpretation. In one case, a bland thrombus developed in the 13-day interval from CT to transplantation. In this case, a small 1.5-cm HCC tumor that was found at pathologic analysis was not detectable at CT. In the second case, a bland thrombus with a few clusters of HCC cells was found at pathologic analysis. The interpreting pathologist could not determine whether the few clusters of HCC cells were artifactual, related to specimen sectioning, or representative of vascular invasion by tumor. In this case, a 3-cm lesion, subsequently proved at pathologic analysis to be HCC, was detected at initial CT before portal vein thrombus developed and at follow-up pretransplantation CT.


    DISCUSSION
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Accurate surveillance of patients with cirrhosis for possible HCC is of great clinical importance, because these patients are at increased risk for HCC, and tumor treatment, including transplantation, is more effective in those with smaller tumors. The clinical examination of transplantation candidates with cirrhosis includes medical history, physical examination, laboratory tests, and imaging studies. Although the medical history and physical examination results often confirm complications of portal hypertension, they do not enable an accurate assessment of the possible presence of HCC. Laboratory tests for patients with cirrhosis include the serum AFP level (16). An elevated AFP level often reflects HCC, but AFP testing alone is not enough to make an accurate diagnosis in all patients with HCC, because false-negative AFP test results are common, particularly with small tumors (16). Furthermore, false-positive AFP test results may be seen with cirrhosis and with flares of active hepatitis (4).

Imaging in the transplantation candidate with cirrhosis, which is often performed with CT, helps to confirm suspected manifestations of portal hypertension and enables noninvasive imaging of the liver parenchyma and major hepatic vessels. Recent technologic advances in CT scanner design have led to the implementation of helical scanning techniques that enable imaging of the entire liver in both the early phase of hepatic arterial parenchymal contrast enhancement and the slightly later phase of portal venous parenchymal contrast enhancement (15,1719). Because virtually all primary liver tumors are perfused predominantly by the hepatic arterial circulation, the ability to rapidly scan the entire liver during the arterial phase of enhancement allows increased detection of hypervascular arterial phase enhancing tumors (18,19). Furthermore, the ability to rapidly scan the liver again during the portal venous phase of enhancement facilitates the detection of less vascular tumors that are not hypervascular on initial arterial phase images (19).

Although inclusion of nonenhanced CT occasionally facilitates the detection of less common HCC tumors that are enhancing to a similar degree as normal liver and consequently are not visible on contrast-enhanced images (19), the use of nonenhanced or portal venous phase CT alone is inadequate to effectively examine patients with cirrhosis for possible HCC. In patients who cannot undergo contrast-enhanced CT because of renal insufficiency or sensitivity to iodinated contrast material, dynamic gadolinium-enhanced magnetic resonance (MR) imaging is an effective alternative (20).

The reported sensitivities of CT for HCC detection vary, although in an earlier, often-referenced well-written and well-performed study of the efficacy of imaging for detecting HCC, CT reportedly depicted tumor in 84 (84%) of 100 patients with small (<3-cm) tumors (21). This reported detection rate, however, was from a retrospective unblinded study of CT scans obtained in only patients referred with known tumors. Patients at high risk for tumor but with no detected tumor were not included. Consequently, that study did not include patients with tumors and false-negative entry CT studies, because these were not corroborated with follow-up imaging or pathologic correlation. This bias due to the exclusion of false-negative CT studies can lead to higher reported CT tumor detection rates.

A valuable feature of our study was the prospective direct correlation of surgical pathologic findings with preoperative CT scan findings in a large surveillance population of patients with cirrhosis but without known or suspected HCC who were referred for transplantation evaluation. Unlike earlier studies (21,22) of tumor detection rates at imaging that involved the retrospective assessment of imaging modality efficacy in cases of known tumors, in our study we correlated the surgical pathologic findings in all 430 transplant recipients—both with and without HCC—with the preoperative CT findings.

Studies in which an imaging modality is evaluated for detection of a disease diagnosed by using a surgical procedure performed only in cases of a positive imaging result cannot avoid major biases. In such studies, designed so that only those patients with positive imaging results undergo surgery, retrospective review of imaging efficacy in surgically proved cases circuitously leads to spuriously high imaging examination sensitivity. A study of this design also has an inherent bias due to the exclusion of patients who did not have a positive imaging result and consequently did not undergo the surgical procedure. In other words, such a study does not include the further examination of those patients with negative (both true and false) imaging results. This leads to a higher reported sensitivity of disease detection, because the patients with false-negative imaging results do not undergo the diagnostic procedure performed because of positive imaging results and are consequently excluded from further analysis.

The examination of all patients with cirrhosis who are referred for transplantation without suspicion of tumor, even those who are found not to have tumor, enables a more accurate assessment of the sensitivity of surveillance CT imaging. This is the most likely reason that the tumor detection rate in our study, which was not limited to patients with positive imaging findings and included those with both true- and false-negative CT results, was lower than that in previous reports (21,22).

Furthermore, prospective direct imaging-pathologic correlation of the entire liver at the time of gross surgical pathologic evaluation allows a more comprehensive pathologic reference standard for the assessment of tumor detection. Because of the intensive examination of surgical specimens in our study, a larger number of HCC tumors may have been identified compared with that detected with other tumor detection imaging studies that had less intensive or less directed examination of surgical specimens. The additional tumors identified with a more extensive examination of the pathologic specimen often are small tumors, as reflected in the mean size of the tumor nodules seen only at pathologic analysis in our study—1.3 cm. The detection of these additional small tumors at pathologic analysis, which probably would not have occurred with less intensive specimen examination, probably also contributed to the higher false-negative CT detection rate in our study compared with that in prior studies.

As shown in Table 1, our results indicated that different prevalences of HCC were associated with different causes of end-stage liver disease. The highest prevalence of unsuspected HCC (27%) was found in patients with cirrhosis secondary to hepatitis B infection. A prevalence of 22% was observed in patients with hepatitis C, the most common cause of cirrhosis in our transplant recipient population. These findings indicate that patients with cirrhosis secondary to viral hepatitis should undergo particularly careful tumor surveillance. Any lesions suspicious for tumor that are detected at CT or any other imaging examination in patients with cirrhosis—especially those with cirrhosis secondary to viral hepatitis or alcohol-related disease, which have higher prevalences of HCC—should be carefully evaluated further, usually with biopsy.

The time from surveillance CT to transplantation has been shown to inversely correlate with tumor detection at CT. A small number of false-negative CT studies reflect observer errors or "misses" at scan interpretation—that is, tumors visible retrospectively at direct correlation with the explanted liver specimen findings that were not diagnosed prospectively (Fig 2). However, many false-negative CT studies, particularly those performed with the optimal triphasic technique, more likely reflect interval tumor development or growth between the time of CT and the time of transplantation. In a few cases, a false-negative CT study represents true failure of the technique to depict tumor (Fig 3).



View larger version (153K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 3a. Hepatitis B and a small HCC tumor that was not diagnosed prospectively at triphasic contrast-enhanced helical CT or retrospectively at CT in a 63-year-old man. (a) Transverse arterial phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (b) Transverse portal venous phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (c) Gross pathologic liver specimen confirms the presence of a 10-mm, well-differentiated HCC tumor (arrow), which was not visible at CT performed only 1 day before transplantation.

 


View larger version (158K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 3b. Hepatitis B and a small HCC tumor that was not diagnosed prospectively at triphasic contrast-enhanced helical CT or retrospectively at CT in a 63-year-old man. (a) Transverse arterial phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (b) Transverse portal venous phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (c) Gross pathologic liver specimen confirms the presence of a 10-mm, well-differentiated HCC tumor (arrow), which was not visible at CT performed only 1 day before transplantation.

 


View larger version (154K):
[in this window]
[in a new window]
[Download PPT slide]
 
Figure 3c. Hepatitis B and a small HCC tumor that was not diagnosed prospectively at triphasic contrast-enhanced helical CT or retrospectively at CT in a 63-year-old man. (a) Transverse arterial phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (b) Transverse portal venous phase helical CT image shows cirrhotic liver without an identifiable mass. The arrow points to the region of tumor seen on the pathologic specimen (c). (c) Gross pathologic liver specimen confirms the presence of a 10-mm, well-differentiated HCC tumor (arrow), which was not visible at CT performed only 1 day before transplantation.

 
Tumor measurements obtained from surgical pathologic specimens reflect the tumor sizes at the time of transplantation, not necessarily the sizes at the time of CT (Fig 2). In the current study, surgical pathologic measurements of tumor nodules were used for consistency, because some tumors were not visible (and possibly had not yet developed) at the time of CT. This phenomenon likely accounted for most of the cases of undiagnosed tumor in which transplantation was delayed more than 67 days after the CT examination (Table 3). For this reason, it is important that patients with cirrhosis who are of high priority on transplant waiting lists, particularly those with viral hepatitis, undergo helical CT at least every 6 months while awaiting transplantation. An unacceptably higher number of HCC tumors will be undiagnosed before transplantation if regular interval CT scanning is delayed before transplantation in these patients.

A 6-month interval for surveillance of patients with cirrhosis for possible HCC also has been proposed by other authors (4) as a reasonable approach, given that the median tumor doubling time for HCC tumors smaller than 5 cm has been reported to be 117 days. Although undiagnosed tumors are usually stage I tumors, HCC has variable biologic behavior and small tumors can grow to advanced-stage disease in a short time.

Our study was not without limitations. As a large epidemiologic study with hundreds of patients, some variables (eg, time of CT relative to time of transplantation) could not be rigorously controlled. Unlike in smaller controlled studies, in our study we did not attempt to evaluate interobserver variability in scan interpretation or specific diagnostic signs for HCC diagnosis. Our data reflect our experience in an academic tertiary-care medical center with an active transplantation program, with determination of HCC prevalence in patients with end-stage cirrhosis and assessment of the sensitivity of practical surveillance CT—particularly helical triphasic scanning—for HCC tumor detection.

Of additional interest is the spectrum of other lesions that may mimic HCC, particularly at arterial phase CT. Although this topic was beyond the scope of our current study, it merits further investigation. Finally, it has been observed that the rate of contrast material administration can affect the capability of CT to depict hypervascular lesions at arterial phase contrast-enhanced CT (23). A minority of the patients underwent biphasic scanning with a slower contrast material injection rate (2.5 mL/sec) early in our study; this may have affected the effectiveness of CT for tumor detection in this small group of patients.

Our study results represent data on the epidemiology of HCC in a large surveillance population of patients with cirrhosis who were referred for transplantation evaluation without known or clinically suspected tumor. Because these patients were not suspected of having tumor, they represented a true surveillance population, not a series of consecutive transplant recipients. Although HCC detection is also possible with ultrasonography (US) or MR imaging, US does not readily lend itself to as strict an imaging-pathologic correlation as does CT, because US documentation of the entire volume of liver tissue is not routinely performed. Although MR imaging is a powerful technique for liver imaging, to our knowledge, a large study of MR imaging surveillance of patients with cirrhosis but without known or clinically suspected HCC who have undergone transplantation has not been published.

CT scanning is a common powerful noninvasive diagnostic examination with a greater sensitivity for detection of small HCC tumors than serum AFP screening, but it must be performed with the optimal triphasic helical technique. In summary, clinically unsuspected HCC is most prevalent with cirrhosis secondary to hepatitis B or C, and, when evaluated at CT, is best detected with triphasic contrast-enhanced helical scanning performed within 67 days before transplantation.


    ACKNOWLEDGMENTS
 
We thank the other members of our abdominal imaging division for their participation in imaging and pathologic correlation.


    FOOTNOTES
 
Abbreviations: AFP = {alpha}-fetoprotein, HCC = hepatocellular carcinoma

Author contributions: Guarantor of integrity of entire study, R.L.B.; study concepts and design, R.L.B.; definition of intellectual content, M.S.P., R.L.B.; literature research, M.S.P.; clinical studies, all authors; data acquisition, R.L.B., S.R.C., L.E.H., M.S.P., J.H.O.; data analysis, M.S.P., R.L.B.; manuscript preparation, M.S.P.; manuscript editing, M.S.P., R.L.B.; manuscript review, M.S.P., R.L.B., J.W.M.


    REFERENCES
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. El-Serag HB, Mason AC. Rising incidence of hepatocellular carcinoma in the United States. N Engl J Med 1999; 340:745-750.[Abstract/Free Full Text]
  2. Johnson RC. Hepatocellular carcinoma. Hepatogastroenterology 1997; 44:307-312.[Medline]
  3. Manns MP, Kubicka S. Hepatocellular carcinoma. Digestion 1997; 58(suppl 1):69-75.
  4. Collier J, Sherman M. Screening for hepatocellular carcinoma. Hepatology 1998; 27:273-278.[Medline]
  5. Di Bisceglie AM. Hepatitis C and hepatocellular carcinoma. Hepatology 1997; 26(3 suppl 1):34-38.[Medline]
  6. Trinchet JC, Beaugrand M. Treatment of hepatocellular carcinoma in patients with cirrhosis. J Hepatol 1997; 27:756-765.[Medline]
  7. Bruix J. Treatment of hepatocellular carcinoma. Hepatology 1997; 25:259-262.[Medline]
  8. Rogiers X, Brunken C, Malago M, Knoefel WT, Broelsch CE. Surgical therapy of hepatocellular carcinoma. Digestion 1998; 59(suppl 2):78-79.
  9. Gallkowski U, Low A, Hirner A. Regional chemotherapy and transcatheter arterial chemoembolization. Digestion 1998; 59(suppl 2):83-85.
  10. Mor E, Kaspa RT, Sheiner P, Schwartz M. Treatment of hepatocellular carcinoma associated with cirrhosis in the era of liver transplantation. Ann Intern Med 1998; 15:129:643-653.
  11. Achkar JP, Araya V, Baron RL, Marsh JW, Dvorchik I, Rakela J. Undetected hepatocellular carcinoma: clinical features and outcome after liver transplantation. Liver Transpl Surg 1998; 4:477-482.[Medline]
  12. Marsh JW, Dvorchik I, Subotin M, et al. The prediction of risk of recurrence and time to recurrence of hepatocellular carcinoma after orthotopic liver transplantation: a pilot study. Hepatology 1997; 26:444-450.[Medline]
  13. Clavien PA. Orthotopic liver transplantation for stage III and stage IV hepatocellular carcinoma. Liver Transpl Surg 1997; 3(5 suppl 1):S52-S54.[Medline]
  14. Yokoyama I, Carr B, Saitsu H, Iwatsuki S, Starzl TE. Accelerated growth rates of recurrent hepatocellular carcinoma after liver transplantation. Cancer 1991; 68:2095-2100.[Medline]
  15. Oliver JH, Baron RL. Helical biphasic contrast-enhanced CT of the liver: technique, indications, interpretation, and pitfalls. Radiology 1996; 201:1-14.[Abstract/Free Full Text]
  16. Trojan J, Raedle J, Zeuzem S. Serum tests for diagnosis and follow-up of hepatocellular carcinoma after treatment. Digestion 1998; 59(suppl 2):72-74.
  17. Ohashi O, Hanafusa K, Yoshida T. Small hepatocellular carcinomas: two-phase dynamic incremental CT in detection and evaluation. Radiology 1993; 189:851-855.[Abstract/Free Full Text]
  18. Baron RL, Oliver JH, Dodd GD, 3rd, Nalesnik M, Holbert BL, Carr B. Hepatocellular carcinoma: evaluation with biphasic, contrast-enhanced, helical CT. Radiology 1996; 199:505-511.[Abstract/Free Full Text]
  19. Oliver JH, Baron RL, Federle MP, Rockette HE. Detecting hepatocellular carcinoma: value of unenhanced or arterial phase CT imaging or both used in conjunction with conventional portal venous phase contrast-enhanced CT imaging. AJR Am J Roentgenol 1996; 167:71-77.[Abstract/Free Full Text]
  20. Peterson MS, Baron RL, Murakami M. Hepatic malignancies: usefulness of acquisition of multiple arterial and portal venous phase images at dynamic gadolinium-enhanced MR imaging. Radiology 1996; 201:337-345.[Abstract/Free Full Text]
  21. Takayasu K, Moriyama N, Muramatsu Y, et al. The diagnosis of small hepatocellular carcinomas: efficacy of various imaging procedures in 100 patients. AJR Am J Roentgenol 1990; 155:49-54.[Abstract/Free Full Text]
  22. Rizzi PM, Kane PA, Ryder SD, et al. Accuracy of radiology in detection of hepatocellular carcinoma before liver transplantation. Gastroenterology 1994; 107:1425-1429.[Medline]
  23. Oliver JH, 3rd, Baron RL. High flow injection rates versus low flow injection rates: does increasing the injection rate result in greater detection of enhancement of hepatocellular carcinoma during hepatic arterial phase CT? (abstr). Radiology 1998; 209(P):215.



This article has been cited by other articles:


Home page
Am. J. Roentgenol.Home page
X. Ma, A. E. Samir, N.-S. Holalkere, and D. V. Sahani
Optimal Arterial Phase Imaging for Detection of Hypervascular Hepatocellular Carcinoma Determined by Continuous Image Capture on 16-MDCT
Am. J. Roentgenol., September 1, 2008; 191(3): 772 - 777.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
J.-J. Chung, J. S. Yu, J. H. Kim, M.-J. Kim, and K. W. Kim
Nonhypervascular Hypoattenuating Nodules Depicted on Either Portal or Equilibrium Phase Multiphasic CT Images in the Cirrhotic Liver
Am. J. Roentgenol., July 1, 2008; 191(1): 207 - 214.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
B. C. Meyer, B. B. Frericks, M. Voges, M. Borchert, P. Martus, J. Justiz, K.-J. Wolf, and F. K. Wacker
Visualization of Hypervascular Liver Lesions During TACE: Comparison of Angiographic C-Arm CT and MDCT
Am. J. Roentgenol., April 1, 2008; 190(4): W263 - W269.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
A. Ronzoni, D. Artioli, R. Scardina, L. Battistig, E. Minola, S. Sironi, and A. Vanzulli
Role of MDCT in the Diagnosis of Hepatocellular Carcinoma in Patients with Cirrhosis Undergoing Orthotopic Liver Transplantation
Am. J. Roentgenol., October 1, 2007; 189(4): 792 - 798.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
P.-Y. Brillet, V. Paradis, G. Brancatelli, A.-S. Rangheard, Y. Consigny, A. Plessier, F. Durand, J. Belghiti, D. Sommacale, and V. Vilgrain
Percutaneous radiofrequency ablation for hepatocellular carcinoma before liver transplantation: a prospective study with histopathologic comparison.
Am. J. Roentgenol., May 1, 2006; 186(5 Suppl): S296 - S305.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
Y. K. Kim, C. S. Kim, G. H. Chung, Y.-M. Han, S. Y. Lee, S. B. Chon, and J. M. Lee
Comparison of Gadobenate Dimeglumine-Enhanced Dynamic MRI and 16-MDCT for the Detection of Hepatocellular Carcinoma
Am. J. Roentgenol., January 1, 2006; 186(1): 149 - 157.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
S. H. Kim, D. Choi, S. H. Kim, J. H. Lim, W. J. Lee, M. J. Kim, H. K. Lim, and S. J. Lee
Ferucarbotran-Enhanced MRI Versus Triple-Phase MDCT for the Preoperative Detection of Hepatocellular Carcinoma
Am. J. Roentgenol., April 1, 2005; 184(4): 1069 - 1076.
[Abstract] [Full Text] [PDF]


Home page
RadiologyHome page
P. V. Pandharipande, G. A. Krinsky, H. Rusinek, and V. S. Lee
Perfusion Imaging of the Liver: Current Challenges and Future Goals
Radiology, March 1, 2005; 234(3): 661 - 673.
[Abstract] [Full Text] [PDF]


Home page
RadiologyHome page
R. Iannaccone, A. Laghi, C. Catalano, P. Rossi, F. Mangiapane, T. Murakami, M. Hori, F. Piacentini, I. Nofroni, and R. Passariello
Hepatocellular Carcinoma: Role of Unenhanced and Delayed Phase Multi-Detector Row Helical CT in Patients with Cirrhosis
Radiology, February 1, 2005; 234(2): 460 - 467.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
I. E. Steingruber, A. Mallouhi, B. V. Czermak, P. Waldenberger, E. Gassner, F. Offner, A. Chemelli, A. Koenigsrainer, W. Vogel, and W. R. Jaschke
Pretransplantation Evaluation of the Cirrhotic Liver with Explantation Correlation: Accuracy of CT Arterioportography and Digital Subtraction Hepatic Angiography in Revealing Hepatocellular Carcinoma
Am. J. Roentgenol., July 1, 2003; 181(1): 99 - 108.
[Abstract] [Full Text] [PDF]


Home page
ANN INTERN MEDHome page
S. Gupta, S. Bent, and J. Kohlwes
Test Characteristics of {alpha}-Fetoprotein for Detecting Hepatocellular Carcinoma in Patients with Hepatitis C: A Systematic Review and Critical Analysis
Ann Intern Med, July 1, 2003; 139(1): 46 - 50.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
R. C. Carlos, H. M. Kim, H. K. Hussain, I. R. Francis, H. V. Nghiem, and A. M. Fendrick
Developing a Prediction Rule to Assess Hepatic Malignancy in Patients with Cirrhosis
Am. J. Roentgenol., April 1, 2003; 180(4): 893 - 900.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
G. Brancatelli, R. L. Baron, M. S. Peterson, and W. Marsh
Helical CT Screening for Hepatocellular Carcinoma in Patients with Cirrhosis: Frequency and Causes of False-Positive Interpretation
Am. J. Roentgenol., April 1, 2003; 180(4): 1007 - 1014.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
B. Bhartia, J. Ward, J. A. Guthrie, and P. J. Robinson
Hepatocellular Carcinoma in Cirrhotic Livers: Double-Contrast Thin-Section MR Imaging with Pathologic Correlation of Explanted Tissue
Am. J. Roentgenol., March 1, 2003; 180(3): 577 - 584.
[Abstract] [Full Text] [PDF]


Home page
RadiologyHome page
S. A. Teefey, C. C. Hildeboldt, F. Dehdashti, B. A. Siegel, M. G. Peters, J. P. Heiken, J. J. Brown, E. G. McFarland, W. D. Middleton, D. M. Balfe, et al.
Detection of Primary Hepatic Malignancy in Liver Transplant Candidates: Prospective Comparison of CT, MR Imaging, US, and PET
Radiology, February 1, 2003; 226(2): 533 - 542.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
S. R. Baker
Abdominal CT Screening: Inflated Promises, Serious Concerns
Am. J. Roentgenol., January 1, 2003; 180(1): 27 - 30.
[Full Text] [PDF]


Home page
Radiology