| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Gastrointestinal Imaging |
1 From the Departments of Radiology (C.D., T.d.B., V.K., P.P., A.R., R.B.), Surgery (D.E.), and Medicine (M.D., V.B.), Institut Gustave-Roussy, 39 rue Camille Desmoulins, 94805 Villejuif, France. From the 1999 RSNA scientific assembly. Received April 16, 2001; revision requested June 4; revision received July 30; accepted September 17. Address correspondence to C.D. (e-mail: dromain@igr.fr).
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
MATERIALS AND METHODS: Thirty-one patients with 50 tumors (nine hepatocellular carcinomas and 41 metastases) treated with RF ablation underwent CT and MR imaging on the same day at 2, 4, and 6 months; CT was performed every 3 months thereafter. CT and MR findings were interpreted separately and prospectively by two reviewers with consensus. For both imaging techniques, appearance of the treated area, treatment efficacy, and complications were assessed at each time. Sensitivity and specificity were determined by using the McNemar test.
RESULTS: After a mean follow-up of 19 months, nine tumors showed local regrowth. At 2 months, MR imaging depicted more local regrowths (eight of nine; sensitivity, 89%) than did CT (four of nine; sensitivity, 44%) but without significant differences (P = .12). In two cases, only T2-weighted imaging depicted local regrowth. All nine lesions became conspicuous at 4-month follow-up with both techniques. At 2 months, thin peripheral rim enhancement and arterioportal shunting were found in 24% and 12%, respectively, of the treated tumors. These findings disappeared thereafter and are not linked to tumor regrowth.
CONCLUSION: Despite the small number of patients, CT and MR imaging may depicted all local regrowth at 4 months or sooner. MR imaging may have an edge over CT in the early detection of local regrowth.
© RSNA, 2002
Index terms: Liver neoplasms, CT, 76.12111, 76.12112, 76.113, 76.12115 • Liver neoplasms, MR, 76.121411, 76.121412, 76.121415, 76.12143 • Liver neoplasms, therapy, 76.1269, 76.323 • Radiofrequency (RF) ablation, 76.1269
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
Imaging plays a crucial role in the follow-up of hepatic tumors treated with RF ablation, as it is the means by which local treatment efficacy, recurrent disease, and some of therapy-induced complications are evaluated. Today, there is no clear consensus about which imaging techniques are most suited for follow-up after RF treatment, and a number of various imaging techniques were performed in different institutions. The goals of our study were to describe the appearance of hepatic tumors treated with RF ablation on computed tomographic (CT) and magnetic resonance (MR) images and the pattern of residual tumor at the site of RF ablation and to assess prospectively the respective sensitivity, specificity, and positive and negative predictive CT and MR imaging values in the evaluation of RF treatment.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
In all patients, histologically proven hepatocellular carcinoma (n = 9) or metastases (n = 41) were considered unresectable. Primary tumors that gave rise to metastatic lesions were colorectal (n = 25), carcinoid (n = 5), desmoplastic small round cell (n = 4), breast carcinoma (n = 4), renal leiomyosarcoma (n = 1), renal adenocarcinoma (n = 1), and medullary thyroid carcinoma (n = 1). In 19 patients, solitary tumors required treatment; in the remaining 12 patients, two to four tumors required treatment. The greatest tumor diameter immediately before treatment was 7–45 mm (mean, 20 mm).
RF Ablation Procedure
All tumors were treated with RF ablation by using a 480-kHz RF generator (CC1; Radionics, Burlington, Mass) that delivered a maximum power of 200 W through 17-gauge monopolar cooled needle electrodes. A single needle with a 2- or 3-cm-long active tip was used for tumors smaller than 2.5 cm (18 patients with 35 tumors). As soon as it was available, a triple-cluster needle (Radionics) composed of three 2.5-cm-long single needles that formed a triangle was used for tumors larger than 2.5 cm (13 patients with 15 tumors). All percutaneous RF procedures were performed by one experienced interventional radiologist (T.d.B.) with ultrasonographic (US) guidance and were monitored by using a 3.5–5.0-MHz probe (AU-Idea; Esaote Biomedica, Le Perreux, France). For all tumors, treatment was considered complete when an RF-induced hyperechoic region totally covered the initial location of the tumor.
Imaging Methods
On the basis of findings at CT and MR imaging performed on the same day, treatment efficacy was prospectively assessed at 2, 4, and 6 months after RF ablation. Subsequently, only CT was performed at 9 and 12 months after the procedure and every 6 months thereafter.
CT images were obtained with a spiral scanner (HiSpeed; GE Medical Systems, Milwaukee, Wis) before and after a bolus injection of 100 mL of nonionic contrast material (iobitridol [Xenetix 300]; Guerbet, Roissy, France) at a rate of 3 mL/sec. A CT injector (Medrad, Pittsburgh, Pa) was used to deliver the contrast medium via a catheter that was inserted into an antecubital vein. After the injection, three spiral CT scans were obtained during the hepatic arterial phase, the portal venous phase, and the equilibrium phase at 30, 70, and 300 seconds, respectively, after initiation of the injection. Scanning was performed at 120 kV and 270 mA. Contiguously reconstructed sections (pitch of 1:1) were obtained through the liver with 7-mm section thickness. Each spiral acquisition through the liver was accomplished during a breath hold.
MR imaging was performed with a 1.5-T whole-body MR imager (Signa LX; GE Medical Systems). All MR images were obtained in the transverse plane with a phased-array multicoil for the body. Section thickness was 7 mm, with a 2-mm intersection gap for all pulse sequences. The imaging protocol comprised fat-suppressed T2-weighted respiratory-triggered fast spin-echo sequences (repetition time msec/echo time msec of 6,000– 11,000 [effective]/100 [effective], echo train length of 16, four signals acquired, interecho spacing of 10 msec, matrix of 256 x 256, bandwidth of 31.25 kHz, field of view of 40 cm, 20% respiratory trigger point, 40% trigger window, gradient moment nulling in the frequency-encoding direction). Saturation bands superior and inferior to the imaging volume were used in the attenuation of flow-related artifacts throughout MR imaging. Dynamic contrast material–enhanced MR imaging was performed at four consecutive 30-second intervals and at 5 minutes after the start of a bolus injection of 0.1 mmol per kilogram of body weight of gadoterate meglumine (Dotarem; Guerbet) into the antecubital vein by using a power injector (Spectris; Medrad). T1-weighted fast multiplanar spoiled gradient-recalled-echo (GRE) sequences (125–150/1.6–4.2, flip angle of 60°, one signal acquired, matrix of 512 x 256, bandwidth of 62.5 kHz, field of view of 40 cm, 25-second breath-hold acquisition) were performed.
Image Analysis
CT and MR images were interpreted independently and prospectively by two radiologists (C.D., T.d.B.) experienced in abdominal CT and MR imaging, who were aware of the RF treatment but were blinded to the initial histopathologic diagnosis, the posttreatment clinical and biologic findings, and the elapsed time from the RF treatment. CT and MR images were read separately for each interval of 2, 4, and 6 months. In cases of interobserver disagreement, the final decisions were reached with consensus. The size and shape of the treated area were evaluated at each imaging follow-up on both CT and MR images. On unenhanced and dynamic contrast-enhanced CT scans, the treated area was classified as hypoattenuating, hyperattenuating, or isoattenuating compared with the surrounding liver parenchyma. In addition, the appearance was classified as homogeneous or heterogeneous. On MR images, the signal intensity pattern of the treated area was compared with that of the surrounding parenchyma and was classified as hyperintense, hypointense, or isointense on T1-, T2-, and contrast-enhanced T1-weighted images, respectively. Homogeneity and heterogeneity were also classified.
According to previous reports (6–8), all contrast-enhanced foci on CT or MR images and/or hyperintense foci on T2-weighted images with nodular shape or irregular thickening of the boundaries of the treated area were considered as suspicious for local tumor regrowths. In such cases, biopsies were performed when suspicious areas could be visualized with US or CT guidance and when biopsy was considered possible with regard to the size (>1 cm) and depth of the area. When the suspected recurrences were not proven at biopsy, they were confirmed on the basis of an increase in size during the imaging follow-up. All areas of RF-induced necrosis that did not demonstrate contrast enhancement within the boundaries of the treated area on CT or MR images and/or hyperintense foci on T2-weighted images were considered as successfully treated tumors. These successful treatments were confirmed with imaging follow-up performed at least 12 months after RF treatment (mean follow-up, 19 months), except in two patients who died of diffuse hepatic metastases during the study period at 7 and 8 months, respectively, after the RF procedure.
With each imaging technique, the features that were of particular interest in this study were the pattern, the size, the location compared with that of blood vessels, and the date of the appearance of local recurrence at the site of the treatment. The appearance of new intrahepatic lesions and the complications generated with RF treatment were also assessed on both CT and MR images.
Statistical Analysis
The Student t test for paired data was used to compare differences between the greatest necrosis RF-induced area diameter measured at both CT and MR imaging, with a threshold P value of .05. Sensitivity, specificity, and positive and negative predictive CT and MR imaging values in the detection of local regrowth were determined with a 95% CI calculated by using the binomial distribution. Differences in sensitivity at 2 months on CT and MR images and on T2-weighted and dynamic contrast-enhanced T1-weighted images were assessed by using paired samples with the McNemar two-sided test (categoric data).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Treatment-related complications depicted on CT and MR images were two clinically unsuspected intrahepatic abscesses at the site of RF application, which were confirmed with percutaneous biopsy and drainage. Incidental imaging findings were one false aneurysm of the puncture tract (diagnosed on the basis of CT and MR imaging findings but not confirmed at arteriography), necrosis along the path of the RF electrode, and segmental dilatation of intrahepatic bile ducts that were in contact with the RF-treated area in three patients. Hepatic hyperperfusion abnormalities, depicted as a typical wedge-shaped homogeneous area of contrast material uptake, were observed at the periphery of the RF-treated area on contrast-enhanced arterial phase CT and MR images in six (12%) patients, without early enhancement of a peripheral portal branch (Fig 5).
|
At 6 months and after, no modification of the pattern of the RF-treated areas was noted. During the imaging follow-up, 27 (66%) of 41 successfully treated tumors decreased in size. This decrease attained a mean of 15% (range, 10%–30%) at 6 months and a mean of 35% (range, 15%–90%) at 12 months. At 2 months, the peripheral rim of enhancement depicted on MR images of 12 treated areas and on CT scans of nine treated areas disappeared in 10 of 12 and seven of nine treated areas, respectively, at 4 months, in 11 of 12 and eight of nine treated areas, respectively, at 6 months, and on all CT scans obtained at 12 months. The wedge-shaped areas of enhancement depicted on contrast-enhanced arterial phase CT and MR images disappeared in four of six RF-treated areas at 4 months and in all cases at 6 months.
New hepatic tumors distant from the RF-treated areas were found in 19 (61%) of 31 patients during follow-up: at 2 months in eight patients, at 4 months in seven patients, at 6 months in three patients, and at 9 months in one patient.
Assessment of the Treatment Response
After a mean follow-up of 19 months, 41 (82%) of 50 hepatic tumors treated with percutaneous RF ablation were considered completely destroyed on imaging studies and nine (18%) showed local regrowth, which was probably due to inadequate RF treatment during the follow-up. Regrowth occurred in RF-ablated hepatocellular carcinoma (n = 2), colorectal metastases (n = 5), breast metastasis (n = 1), and renal adenocarcinoma metastasis (n = 1). Eight of nine local regrowths were depicted 2 months after thermal ablation, and one became conspicuous at 4 months. These local regrowths were confirmed with US or CT-guided biopsies in four cases and with imaging follow-up in five cases.
Among the eight local regrowths detected at 2 months, all were seen on MR images and four were seen on CT scans. At 2 months, the sensitivity, specificity, and positive and negative predictive CT values were 44% (95% CI: 14%, 79%), 100%, 100%, and 89%, respectively, whereas the MR imaging values were 89% (95% CI: 52%, 100%), 100%, 100%, and 97.5%, respectively. At 2 months, the sensitivity of local regrowth detection with MR imaging was not significantly higher compared with that at CT (P = .12). The four local regrowths depicted exclusively on MR images were confirmed 2 months later (4 months after RF treatment), because the size of the suspicious area had increased on MR images and because of the appearance of contrast enhancement on CT scans in areas that were suspect on earlier MR images.
At 2 months, six of the eight local regrowths exhibited moderate high signal intensity on T2-weighted images and contrast material uptake on T1-weighted images. The two remaining local regrowths were detected only on T2-weighted images as a hyperintense nodules abutting the hypointense necrotic area, without suspicious areas being detectable on T1-weighted images before or after contrast medium injection (Fig 6). Nevertheless, the sensitivity of local regrowth on T2-weighted and dynamic contrast-enhanced T1-weighted images did not differ significantly (P > .50). However, in these two cases, enhancement appeared on postcontrast T1-weighted images at 4 months. On CT scans, local regrowths were seen as round or irregular areas of enhancement at the margin of the treatment zone, which corresponded to the area of enhancement on MR images. The appearance of the RF-treated area on CT and MR images is summarized in the Table.
|
|
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
Although US is an efficient tool for monitoring RF treatment, findings from previous reports (6,10–12) have shown the limited value of this technique for the evaluation of treatment efficacy. The echogenicity of necrotic and viable tumor tissue may have a similar appearance on posttreatment US images. As reported by others, US contrast medium, which is currently under investigation in our institution, may help in the future to differentiate tumor from necrosis (13). Contrast-enhanced CT and MR imaging are at present considered the most useful modalities for the assessment of treatment efficacy. Findings from some preliminary reports (7,14) suggest that the size of the nonenhancing region depicted on CT and MR images corresponds to within 2 mm of the size of the coagulated necrosis measured at histologic examination. The criterion commonly used at CT and MR imaging to assess this efficacy is the absence of enhancement in RF-induced necrosis, which corresponds to tissue devoid of viable tumor. In most studies, CT or MR imaging is used variably and indifferently to assess the efficacy of RF treatment but, to our knowledge, the respective values of these two imaging techniques have not yet been reported.
Two months after RF therapy, uniform hypointensity on T2-weighted images, associated with lack of enhancement of the RF-treated area on contrast-enhanced T1-weighted images, always corresponded to complete efficient treatment. Most of the RF-treated areas were hyperintense on unenhanced T1-weighted images, which was probably due to hemorrhage or a proteinaceous material within the RF-treated area. Most of the RF-treated areas were hypointense on T2-weighted images, and this hypointensity could be explained by the dehydrating effect of RF-induced thermal damage that results in coagulative necrosis. However, marked hyperintensity on T2-weighted images, found in 14% of the successfully treated areas, could signify biloma or liquefactive necrosis, as active tumor always displays a less heavily intense T2 signal intensity.
Our study findings show that in four of eight cases, MR imaging allows earlier detection of residual tumor than does CT. Nevertheless, due to the small number of local regrowths in our study, no significant differences between MR images and CT scans at two months could be found. All local regrowths were detected at MR imaging follow-up at 2 months, except for one regrowth that was detected at 4 months. In this case, liquefactive necrotic material, which exhibited markedly high signal intensity on T2-weighted MR images obtained at 2 months, probably masked the less intense signal intensity induced by a minute focus of residual tumor. At 4 months, the area of markedly high signal intensity related to liquefactive necrosis disappeared and residual viable tumor that exhibited moderately high signal intensity was easily detected on T2-weighted images. This moderately high signal intensity corresponded to an area of enhancement on contrast-enhanced T1-weighted images.
The higher sensitivity of MR imaging over CT is mostly due to the T2-weighted images, which were the only imaging studies capable of depicting tumor in two cases at two months. The superior sensitivity of T2-weighted imaging could be explained by an increase in contrast between the coagulated area, which has a low signal intensity, and the viable residual tumor, which has a high signal intensity. Moderate (different from a fluid signal) hyperintensity on T2-weighted images corresponded to the presence of residual viable tumor in all cases. Therefore, T2-weighted imaging is demonstrated to be highly specific. Moreover, the moderately hyperintense area on T2-weighted images associated with corresponding enhancement on contrast-enhanced T1-weighted images offers optimal specificity (100%) for residual viable tumor in all cases.
In our experience, local regrowths were always depicted at the periphery of the treated area either as irregular thickening of one margin of the treated area or a new tumor nodule. These peripheral locations of treatment failures could be explained by lower energy deposition and reduced heating that was remote from the needle electrode. Furthermore, tissue perfusion lowers heat accumulation due to cooling, and this phenomenon is even more marked in tissue in contact with large vessels. Indeed, regrowth close to large vessels arose in two of nine cases in our study and has already been described by others (1,7).
Peripheral regrowth should not be diagnosed when one sees a thin and regular (<1 mm) rim of progressive contrast enhancement, which was present at 2 months in 32% of the entire RF-treated area in our study and better seen at the later phase after contrast material administration. It has been shown by means of comparison with histologic findings that the thin ring is a vascularized inflammatory reaction with granulation tissue surrounding the zone of coagulation necrosis (11,14–16). Similar findings have been described less frequently in hepatocellular carcinoma treated with alcohol injection (17–19) and in hepatic metastases treated with laser-induced thermotherapy (10,20). In our study, the peripheral rim disappeared with time and was present in only 8% of the RF-treated area at 4 months. It can easily be differentiated from an active tumor whose area of contrast enhancement is thicker and irregular. Another RF-induced modification is the presence on arterial phase images of wedge-shaped enhancement in the liver parenchyma adjacent to the RF-treated area, which was present in our study in 12% of patients. This enhancement probably corresponds to peripheral arterioportal shunts caused by either the needle puncture and/or thermal damage. These wedge-shaped areas should not be misinterpreted as tumor contrast material uptake.
Although there are many similarities between the radiologic aspect of RF-induced destruction and the necrosis induced by ethanol (17,18,21), some differences need to be pointed out. First, in our study, T2-weighted MR imaging was demonstrated to be the best indicator of the efficacy of RF treatment. In contrast, Sironi et al (17) and Nagel and Bernardino (21) described a limited value of the T2-weighted signal intensity pattern of tumors injected with alcohol in ascertaining the viability of the tumor. This might be due either to differences in technical parameters (fast spin echo with respiratory monitoring in our study versus standard spin echo with a higher rate of motion artifacts in their studies) or to histopathologic nature of the initial tumors, which is very different in our study from that of these previous reports. Second, the area of RF-induced coagulation necrosis shrank more slowly than that of ethanol-induced necrosis. Indeed, in our study, 66% of the treated area shrank, attaining a mean reduction of 15% at 6 months and 35% at 12 months. Ebara et al (22) reported shrinkage of all treated areas, which attained a mean of 45% at 6 months and 63% at 12 months in 67 hepatocellular carcinomas treated with ethanol. The value of a decrease in size of the RF-treated area appears to be even more limited than it was with alcohol, which was already not very effective given the time to total shrinkage.
Limitations of our study include the small number of patients and lesions, which limited the value of statistical analysis, the heterogeneity of tumor origin, the absence of MR imaging 6-month follow-up, and the lack of biopsy in five cases of suspected local regrowths.
In conclusion, CT and MR imaging are able to help in the accurate assessment of RF treatment efficacy. As reported by others at 6 months, MR imaging and CT depicted all local regrowths at 4 months or earlier. Knowledge of the RF-treatment zone patterns is essential for the correct evaluation of MR imaging and CT follow-up. MR imaging may have an edge over CT in the early detection of local regrowths due to the high sensitivity of T2-weighted imaging, but further studies are needed to confirm the apparent superiority of MR imaging over CT in the detection of local regrowth after RF ablation of hepatic tumors.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
Author contributions: Guarantor of integrity of entire study, C.D.; study concepts, C.D., A.R., T.d.B.; study design, V.B., M.D., C.D., T.d.B.; literature research, C.D., T.d.B.; clinical studies, D.E., M.D., V.B., T.d.B., V.K.; data acquisition, C.D., P.P.; data analysis/interpretation, P.P., C.D., T.d.B.; manuscript preparation, C.D., T.d.B.; manuscript definition of intellectual content, V.K., C.D., T.d.B.; manuscript editing, C.D.; manuscript revision/review and final version approval, C.D., T.d.B., R.S.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  L. F. Pupulim, A. Hakime, V. Barrau, M. Abdel-Rehim, M. Zappa, and V. Vilgrain Fatty Hepatocellular Carcinoma: Radiofrequency Ablation--Imaging Findings Radiology, March 1, 2009; 250(3): 940 - 948. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. de Baere, F. Deschamps, P. Briggs, C. Dromain, V. Boige, L. Hechelhammer, M. Abdel-Rehim, A. Auperin, D. Goere, and D. Elias Hepatic Malignancies: Percutaneous Radiofrequency Ablation during Percutaneous Portal or Hepatic Vein Occlusion Radiology, September 1, 2008; 248(3): 1056 - 1066. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Mulier, T. Ruers, L. Michel, J. Jamart, G. Marchal, and Y. Ni A Place for Radiofrequency Ablation in the Treatment of Resectable Colorectal Liver Metastases? Ann. Surg. Oncol., July 1, 2008; 15(7): 2064 - 2065. [Full Text] [PDF]
|
|
|
|
|
|
J. M. Willatt, H. K. Hussain, S. Adusumilli, and J. A. Marrero MR Imaging of Hepatocellular Carcinoma in the Cirrhotic Liver: Challenges and Controversies Radiology, May 1, 2008; 247(2): 311 - 330. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M.-h. Park, H. Rhim, Y.-s. Kim, D. Choi, H. K. Lim, and W. J. Lee Spectrum of CT Findings after Radiofrequency Ablation of Hepatic Tumors RadioGraphics, March 1, 2008; 28(2): 379 - 390. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. S. Arellano Invited Commentary RadioGraphics, March 1, 2008; 28(2): 390 - 392. [Full Text] [PDF]
|
|
|
|
|
|
A. P. S. Kirkham, M. Emberton, I. M. Hoh, R. O. Illing, A. A. Freeman, and C. Allen MR Imaging of Prostate after Treatment with High-Intensity Focused Ultrasound Radiology, March 1, 2008; 246(3): 833 - 844. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. M. Vogt, G. Antoch, P. Veit, L. S. Freudenberg, N. Blechschmid, O. Diersch, A. Bockisch, J. Barkhausen, and H. Kuehl Morphologic and Functional Changes in Nontumorous Liver Tissue After Radiofrequency Ablation in an In Vivo Model: Comparison of 18F-FDG PET/CT, MRI, Ultrasound, and CT J. Nucl. Med., November 1, 2007; 48(11): 1836 - 1844. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. V. Vogel, J. A. van Dalen, B. Wiering, H. Huisman, F. H.M. Corstens, T. J.M. Ruers, and W. J.G. Oyen Evaluation of Image Registration in PET/CT of the Liver and Recommendations for Optimized Imaging J. Nucl. Med., June 1, 2007; 48(6): 910 - 919. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. L. Keppke, R. Salem, D. Reddy, J. Huang, J. Jin, A. C. Larson, and F. H. Miller Imaging of Hepatocellular Carcinoma After Treatment with Yttrium-90 Microspheres Am. J. Roentgenol., March 1, 2007; 188(3): 768 - 775. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Bricault, R. Kikinis, P. R. Morrison, E. vanSonnenberg, K. Tuncali, and S. G. Silverman Liver Metastases: 3D Shape-based Analysis of CT Scans for Detection of Local Recurrence after Radiofrequency Ablation Radiology, October 1, 2006; 241(1): 243 - 250. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. d. Baere, J. Palussiere, A. Auperin, A. Hakime, M. Abdel-Rehim, M. Kind, C. Dromain, A. Ravaud, N. Tebboune, V. Boige, et al. Midterm Local Efficacy and Survival after Radiofrequency Ablation of Lung Tumors with Minimum Follow-up of 1 Year: Prospective Evaluation. Radiology, August 1, 2006; 240(2): 587 - 596. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|
|
|
|
|
B. B. Frericks, J. P. Ritz, A. Roggan, K.-J. Wolf, and T. Albrecht Multipolar Radiofrequency Ablation of Hepatic Tumors: Initial Experience Radiology, December 1, 2005; 237(3): 1056 - 1062. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Shankar, E. vanSonnenberg, J. Desai, P. J. DiPiro, A. Van Den Abbeele, and G. D. Demetri Gastrointestinal Stromal Tumor: New Nodule-within-a-Mass Pattern of Recurrence after Partial Response to Imatinib Mesylate Radiology, June 1, 2005; 235(3): 892 - 898. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|
|
|
|
|
D. S. K. Lu, N. C. Yu, S. S. Raman, P. Limanond, C. Lassman, K. Murray, M. J. Tong, R. G. Amado, and R. W. Busuttil Radiofrequency Ablation of Hepatocellular Carcinoma: Treatment Success as Defined by Histologic Examination of the Explanted Liver Radiology, March 1, 2005; 234(3): 954 - 960. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Kim, W. K. Moon, J. H. Cha, J. M. Goo, K. H. Lee, K. H. Kim, J. W. Lee, J. G. Han, H.-J. Weinmann, and K. H. Chang VX2 Carcinoma in Rabbits after Radiofrequency Ablation: Comparison of MR Contrast Agents for Help in Differentiating Benign Periablational Enhancement from Residual Tumor Radiology, February 1, 2005; 234(2): 423 - 430. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. H. Kim, H. K. Lim, D. Choi, W. J. Lee, S. H. Kim, M. J. Kim, S. J. Lee, and J. H. Lim Changes in Bile Ducts after Radiofrequency Ablation of Hepatocellular Carcinoma: Frequency and Clinical Significance Am. J. Roentgenol., December 1, 2004; 183(6): 1611 - 1617. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Y. Jin, J. M. Lee, Y. C. Lee, Y. M. Han, and Y. S. Lim Primary and Secondary Lung Malignancies Treated with Percutaneous Radiofrequency Ablation: Evaluation with Follow-Up Helical CT Am. J. Roentgenol., October 1, 2004; 183(4): 1013 - 1020. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Gadaleta, V. Mattioli, G. Colucci, A. Cramarossa, V. Lorusso, E. Canniello, A. Timurian, G. Ranieri, G. Fiorentini, M. De Lena, et al. Radiofrequency Ablation of 40 Lung Neoplasms: Preliminary Results Am. J. Roentgenol., August 1, 2004; 183(2): 361 - 368. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Limanond, P. Zimmerman, S. S. Raman, B. M. Kadell, and D. S. K. Lu Interpretation of CT and MRI After Radiofrequency Ablation of Hepatic Malignancies Am. J. Roentgenol., December 1, 2003; 181(6): 1635 - 1640. [Full Text] [PDF]
|
|
|
|
|
|
T. de Baere, O. Risse, V. Kuoch, C. Dromain, C. Sengel, T. Smayra, M. G. E. Din, C. Letoublon, and D. Elias Adverse Events During Radiofrequency Treatment of 582 Hepatic Tumors Am. J. Roentgenol., September 1, 2003; 181(3): 695 - 700. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Titton, P. C. Gryzenia, D. A. Gervais, R. S. Arellano, G. W. Boland, and P. R. Mueller Continuous High-Output Drainage of Hepatic Abscess 3 Months After Radiofrequency Ablation of Hepatocellular Carcinoma Am. J. Roentgenol., April 1, 2003; 180(4): 1079 - 1084. [Full Text] [PDF]
|
|
|
|
|
|
S. K. Kim, H. K. Lim, Y. H. Kim, W. J. Lee, S. J. Lee, S. H. Kim, J. H. Lim, and S. A. Kim Hepatocellular Carcinoma Treated with Radio-frequency Ablation: Spectrum of Imaging Findings RadioGraphics, January 1, 2003; 23(1): 107 - 121. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A M Connors and S P Blake Multiple-choice questionnaire: general Imaging, October 1, 2002; 14(5): 428 - 437. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| RADIOLOGY | RADIOGRAPHICS | RSNA JOURNALS ONLINE |
