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Vascular and Interventional Radiology |
1 From the Department of Radiology (M.V., E.A., M.S., F.D.C., C.L., A.D.M.), Department of Internal Medicine, Transplant Unit (P.M., P.F., F.B., A.S.), and Department of General Surgery (C.S., L.A., V.D.C.), San Raffaele Scientific Institute, Vita-Salute University, Olgettina 60, 20132 Milan, Italy. From the 2002 RSNA Annual Meeting. Received August 25, 2003; revision requested November 6; final revision received March 31, 2004; accepted April 15. Supported in part by Ministero della Sanità (Ricerca Finalizzata [RF] 1999 and 2001, RF 99.52 and RF 01.184) and Ministero della Ricerca Scientifica (Cofinanziamento 2002). Address correspondence to M.V. (e-mail: venturini.massimo@hsr.it).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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MATERIALS AND METHODS: The institutional review board approved the study, and informed consent was obtained from all patients. After kidney transplantation, 34 uremic diabetic patients (20 men, 14 women; mean age, 40.9 years; age range, 29–61 years) underwent percutaneous intrahepatic transplantation of islet cells. Portal vein patency and liver echotexture were preliminarily assessed with color Doppler US. US also was used to identify early complications and presence (group A patients) or absence (group B patients) of hepatic parenchymal changes. Differences between the two groups in C peptide serum level and range were analyzed (Mann-Whitney test). Therapeutic efficacy of transplantation was assessed with regard to insulin independence period (rate and duration), exogenous insulin requirement, glycated hemoglobin, and C peptide level. A C peptide level of more than 0.5 ng/mL was considered to indicate well-functioning islet cells.
RESULTS: Fifty-eight procedures were technically successful, with a single puncture used in 51 of 58 patients. Complications occurred in three of 58 patients (hemoperitoneum, hemothorax, and thrombosis in one patient each) and were conservatively treated and resolved. Duration of insulin independence in 12 patients was more than 3 months (mean, 21 months). Well-functioning islet cells at 6 years were found in 19 of 34 patients. Hyperechoic parenchymal changes were evident at US in 12 of 34. No statistically significant difference in C peptide level was found between groups (P > .05), but a wider range of values was recorded in group B.
CONCLUSION: Complication rate of transplantation with US and fluoroscopic guidance was low. Well-functioning islet cells were found in about 50% of patients at 6 years of follow-up. Hepatic implantation of islet cells was evident on US images in more than one-third of patients.
© RSNA, 2004
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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Several studies (5–9) have demonstrated that percutaneous intrahepatic transplantation of human pancreatic islet cells can replace the pancreatic endocrine function without major side effects and with liver function preservation in selected patients affected by long-term type 1 diabetes. Injection of purified islets through the portal vein can restore endogenous insulin secretion, achieve insulin independence in some cases, and simultaneously improve the metabolism of glucose, protein, and lipids (10).
In previous reports (5–9), human pancreatic islet cell transplantation was performed mainly by using fluoroscopic guidance alone. In the present study, both ultrasonography (US) and fluoroscopy were used for guidance.
To our knowledge, only one recent report (11) mentions the routine use of US guidance for human pancreatic islet cell transplantation, and no previous reports provide any information about a possible role for US in the assessment of transplanted pancreatic islet cell function.
The purpose of our study was to evaluate the role of US in the technique, complications, and therapeutic efficacy of percutaneous intrahepatic transplantation of human pancreatic islet cells.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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Informed consent was obtained from all of the patients. When our study began in 1989, institutional review board approval was not required. Such approval was required as of 1999, at which time we obtained it. The mean duration of diabetes before transplantation was 26.5 years ± 2.1. Basal and glucagon-stimulated C peptide levels (<0.15 ng/mL) were undetectable before pancreatic islet cell transplantation. Exclusion criteria for islet cell transplantation were previous stroke, major amputation, severe dilated cardiomyopathy, and coronary artery disease. At pancreatic islet cell transplantation, all of the patients with a previously transplanted kidney had good renal function, as indicated by creatinine clearance and creatinine level. In patients with loss of function of transplanted pancreatic islet cells, a second islet cell transplantation was performed. A second procedure was performed when C peptide secretion was less than 0.5 ng/mL and when no substantial decrease in exogenous insulin requirement (more than 50% of preprocedural dose) or improvement in glycated hemoglobin level was found after initial transplantation of pancreatic islet cells.
Pancreas Donor Recruitment
The pancreas to be used for islet cell transplantation was obtained from a brain-dead multiple-organ donor through the North Italian Transplant Organization. Blood group compatibility (ABO system) was observed, but human leukocyte antigen matching was disregarded. The result of cross matching between donor lymphocytes and recipient serum was negative in all cases. The whole pancreas was removed with the duodenum and then stored in University of Wisconsin solution at 4°C until the process of isolating the pancreatic islet cells was begun (cold ischemia time, 3–8 hours).
A relative of the donor gave written informed consent for harvesting each donor pancreas.
Pancreatic Islet Cell Isolation and Purification
Pancreatic islet cells were isolated by using an automated procedure and purified by centrifugation with a discontinuous gradient as previously described (12). Islet cells were then cultured in a humidified atmosphere (5% CO2) in M199 medium supplemented with 10% fetal calf serum, 100 U/mL penicillin, 100 µg/mL streptomycin sulfate, and 2 mmol/L glutamine (Seromed Biochrom, Berlin, Germany) for 12–24 hours before transplantation.
Quantitative and Qualitative Assessment of Islet Cells
Pancreatic islet cell preparations were considered adequate for transplantation according to the following criteria: (a) presence of sterility, defined as absence of aerobic and anaerobic bacteria, fungi, and mycoplasma; (b) presence of more than 6000 equivalent islet cells per kilogram body weight, determined with islet cell volume and insulin content measurements in 100-µL aliquots of the preparation (quantification of pancreatic islet cells was performed in equivalent islet cells to account for variations in cell volume, with an average standard pancreatic islet cell diameter of 150 µm, as previously described by Ricordi et al [13]; the actual number of islet cells also was counted [F.B.]); (c) purity greater than 20%, determined with morphometric analysis and with the ratio obtained by dividing the estimated islet cell mass by the total mass of the preparation; and (d) islet cell viability, assessed with propidium iodide stain.
Preprocedural Evaluation with US
Liver echotexture and portal vein patency with regular blood-flow direction were preliminarily assessed with color Doppler US (M.V., E.A., M.S.). All preliminary assessments were performed with a commercially available US imager (ATL HDI 3000 or HDI 5000; Philips Medical Systems, Bothell, Wash).
US-guided Percutaneous Intrahepatic Transplantation
Pancreatic islet cell transplantation was performed 12–48 hours after isolation of islet cells, according to the protocol approved by the institutional review board. All of the procedures were performed in an angiographic suite by using combined US and fluoroscopic guidance.
A US imager (AU590; Ansaldo/Esaote, Genoa, Italy) was used for guidance during right portal vein puncture with a 22-gauge needle by using a right-sided intercostal approach and local anesthesia. The US-guided procedure differed from the standard fluoroscopically guided procedure in that only the lateral wall of the vein was crossed. In 52 (90%) of 58 procedures, a single operator (M.V., E.A., M.S., F.D.C.) performed the right portal vein puncture by inserting the needle with the right hand while holding the US probe (3.5-MHz convex or 5-MHz microconvex) in the left hand to guide the puncture. In six (10%) of 58 procedures, because of hardness of the liver, both hands were used to insert the needle while a second operator held the US probe to guide the procedure. Color Doppler US was used to visualize and avoid hepatic arteries or veins during needle advancement toward the right portal vein.
Fluoroscopic guidance was used to perform main trunk portal vein catheterization as follows: A 0.018-inch guidewire was advanced through the needle into the main portal vein, and a straight end-hole 4-F catheter was positioned over the guidewire. Portography was performed before and after infusion of pancreatic islet cells to confirm correct positioning of the catheter and patency of the portal vein.
About 150 mL of a preparation containing 300 000–800 000 purified pancreatic islet cells in suspension was slowly injected (20–30 minutes) via the catheter. In addition, 1500–2000 IU of heparin was infused into the portal vein with the islet cell suspension. A slow injection may be important to avoid possible rupture of islet cells while they are in the catheter. Signs of possible complication, such as retching or vasovagal reaction, were evaluated during the intravenous infusion of islet cells.
Before and after pancreatic islet cell transplantation, portal vein pressure was measured to monitor for changes. Portal vein pressure was recorded (in millimeters of mercury) by using a pressure transducer (Propaq 104EL; Protocol Systems, Beaverton, Ore) connected to the catheter.
At the end of the procedure, the catheter was retracted slowly from the intrahepatic tract by using fluoroscopic guidance. In the event of substantial bleeding seen in the external part of the catheter and lasting 2–3 minutes, intrahepatic tract embolization was performed by using gelatin sponge pledgets.
Enoxaparin, 6000 IU/d, was administered subcutaneously for 7 days after the procedure.
Follow-up Evaluations with US
All examinations were performed by radiologists (M.V., E.A., M.S.) with more than 10 years of experience with color Doppler US. Immediately after the transplantation procedure (and at 1, 3, and 7 days thereafter), patients were examined with color Doppler US for signs of bleeding or thrombosis (eg, fluid collection around the liver or absence of flow into the portal vein, respectively), and those with possible thrombosis were examined also with contrast-enhanced computed tomography (CT). Color Doppler US examination was repeated at 1, 6, and 12 months after transplantation, and at 12-month intervals thereafter, to assess portal vein patency and liver echotexture. Parenchymal changes evidenced by hyperechoic areas that were not visible on US images obtained before transplantation were assessed with follow-up US. Patients with liver parenchymal changes (group A) were distinguished from patients with no changes in liver echotexture (group B). In both groups, the levels and range of C peptide values were measured at 6 months after islet cell transplantation to evaluate the islet cell function.
Immunosuppression
All patients continued to receive immunosuppressive therapy previously established for the transplanted kidney, a regimen that included steroids, azathioprine, mycophenolate mofetil, and cyclosporine. After induction with antithymocyte globulin (Thymoglobulin; IMTIX-SangStat, Vienna, Austria), immunosuppressive therapy was based on cyclosporine (100–250 ng/mL), mycophenolate mofetil (500–2000 mg/d), azathioprine (50–100 mg/d), and methylprednisolone (10 mg/d). In 21 patients, steroids were withdrawn from the regimen 3–6 months after pancreatic islet cell transplantation because of the onset of systemic hypertension or ocular disease (cataract, retinal hemorrhage), and in 13 patients steroid therapy was maintained indefinitely.
Postprocedural Monitoring and Management
For the first 10 days after transplantation, blood glucose levels were kept at 5.5–8.2 mmol/L with continuous intravenous insulin administration, and subsequently, with intensified subcutaneous insulin therapy (three injections per day). Insulin doses were progressively tapered according to blood glucose levels and interrupted when fasting and postprandial blood glucose levels were less than 6.6 and 8.8 mmol/L, respectively.
Outcome Measures
Total number of procedures, mean number of infusions for each patient, interval between procedures, procedural success rate, number of puncture attempts, problems with catheterization, pre- and postinfusion portal vein patency, infusion-related complications, changes in portal pressure, and number of intrahepatic tract embolizations were assessed.
Major and minor postprocedural complications and alteration of kidney and liver function also were evaluated.
Therapeutic Efficacy
Rate and duration of insulin independence, C peptide serum concentration, glycated hemoglobin, and exogenous insulin requirement were evaluated. C peptide serum concentration of more than 0.5 ng/mL was considered to indicate well-functioning pancreatic islet cells.
C peptide serum concentration, exogenous insulin requirement, glycated hemoglobin, and percentage of patients with well-functioning islet cells were evaluated at 1, 6, 12, 24, 36, 48, 60, 72, and 84 months after transplantation.
Statistical Analysis
Data are expressed as mean ± standard error of the mean. A 
2 test (for categorical variables) and a two-tailed unpaired Student t test (for parametric data) were used to evaluate differences in the proportion of men versus women and in age, respectively.
The Wilcoxon test (for paired nonparametric data) was used to evaluate changes in portal vein pressure after intravenous infusion of pancreatic islet cells.
The Mann-Whitney test (for nonparametric data) was used to evaluate the difference in C peptide serum concentration between groups A and B.
A P value of less than .05 (two-tailed test) was considered to indicate a statistically significant difference. Analyses of data were performed by using statistical software (SPSS, version 10.1; SPSS, Chicago, Ill).
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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With US guidance, right portal vein puncture (Fig 1) was quickly performed in all patients. A single puncture attempt was successful in 51 (89%) of 58 procedures. Two or three attempts were necessary in seven (11%) of 58 cases because marked steatosis had reduced portal vein visibility; main trunk portal vein catheterization was easily achieved in all cases.
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No complications were observed during islet cell infusion, which was well tolerated in all patients.
A statistically significant increase (P < .05) in portal vein pressure occurred after islet cell infusion (17.25 mm Hg ± 1.86 vs 14.50 mm Hg ± 0.96).
Intrahepatic tract embolization was performed because of prolonged bleeding observed at catheter retraction in 19 (32%) of 58 procedures. The bleeding in all 19 cases was stopped by embolization.
Complications
Early complications occurred in three (5%) of 58 procedures: Hemoperitoneum, hemothorax, and segmental right portal vein thrombosis occurred in one case each. Both cases of bleeding were diagnosed with US within 24 hours after islet cell transplantation. On US images in the patient with hemoperitoneum, fluid collection (blood) was evident around the liver (Fig 2). Hemoperitoneum spontaneously resolved within a few days. In the patient with hemothorax, US images showed an inhomogeneous area in the right supraphrenic region. Pleural drainage and two blood transfusions were performed, and the hemothorax resolved after 1 week of hospitalization.
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No complications related to liver or kidney function were observed, and no alteration in hepatic enzymes was found in any patient.
Therapeutic Efficacy
Twelve patients maintained insulin independence for more than 3 months. In these 12 patients, the mean duration of insulin independence was 21 months ± 4.2. In patients who were not insulin independent after islet cell transplantation, various levels of reduction in the exogenous insulin requirement related to transplanted islet cell function nevertheless were achieved.
Data from the follow-up period, with regard to the percentage of patients with well-functioning pancreatic islet cells (C peptide serum concentration of more than 0.5 ng/mL), mean level of C peptide serum concentration, mean percentage of glycated hemoglobin, and exogenous insulin requirement, are reported in the Table and represented in Figure 4.
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No significant differences (P > .05) were found in mean C peptide serum concentration between the two groups, but a larger range of C peptide values was found in group B than in group A (Fig 6).
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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Percutaneous transhepatic portal vein catheterization, usually performed in an angiographic suite, is a less invasive, repeatable alternative to surgical transplantation (8,14–16). In most studies about human pancreatic islet cell transplantation, fluoroscopic guidance alone has been used during catheterization of the portal vein (17). After transhepatic horizontal advancement of the needle toward the presumed site of the portal vein, the needle is gradually withdrawn until blood is freely aspirated, and the portal vein is then catheterized with fluoroscopic guidance. Described by Lunderquist and Vang (18), this method may require multiple puncture attempts. An average of 5.1 puncture attempts for percutaneous transhepatic portography was reported by Kimura et al (19) with the so-called single-puncture method. Rarely is the number of puncture attempts needed for successful portal vein catheterization quantified in studies of human pancreatic islet cell transplantation.
A combined CT- and fluoroscopy-guided technique was used for pancreatic islet cell transplantation by Weimar et al (20), who reported a single puncture in 39 of 44 patients, with the only complication being a minor hematoma that required no treatment. With this method, after placement of a 5-F sheath in the right portal branch with CT guidance, the patient was transferred to the angiographic suite, and the procedure continued with fluoroscopic guidance. Mean duration of the procedure was not reported.
In the present study, a combined US- and fluoroscopy-guided technique was investigated. To our knowledge, only Goss et al (11) have reported the routine use of US guidance to perform portal vein puncture in percutaneous transplantation of human pancreatic islet cells. US also was used previously for guidance during islet cell transplantation in the kidney capsule (21). US-guided percutaneous punctures of the liver have been described since the early 1980s (22). The advantages of using US for guidance have increased with technical improvements in US units. High-intensity echoes from the indentation of the needle and displacement of the punctured tissues help the operator to locate the position of the needle and target distance. In our experience, a single operator easily and quickly punctured the right portal vein, crossing only its lateral wall, guiding the puncture by holding the US probe in the left hand. The small and easily managed microconvex probe was particularly useful for guiding the needle through the intercostal spaces. Color Doppler US was useful to plan needle advancement into the liver while avoiding branches of the hepatic artery and vein.
In our experience, this method allowed portal vein catheterization with a single puncture attempt in 51 (89%) of 58 procedures and with two or three attempts in the remaining seven procedures. Goss et al (11), who also used US guidance, reported an average of two (range, one to six) attempts in 17 cases.
Reduction in the number of puncture attempts, real-time evaluation of needle intrahepatic advancement, single-wall portal vein puncture, and early assessment of bleeding at the end of the procedure are significant advantages of US guidance over the conventional method of portal vein puncture with fluoroscopic guidance. A reduced rate of complications also may be obtained. Moving and transferring patients, as in CT-guided procedures, can be avoided by reducing the mean duration of the procedure.
A moderate acute increase in portal vein pressure was found after islet cell infusion. A substantial increase in portal pressure may indicate a major risk of thrombosis, as previously described by Casey et al (23).
Complications
Complications of pancreatic islet cell transplantation were not always quantified in previous reports. Some authors have described single complications occurring after islet cell transplantation (24,25), but reports of total complications related to percutaneous procedures in large patient cohorts are rare.
In 2002, Ryan et al (16) reported five cases of bleeding (four of which required transfusion), two cases of right portal vein thrombosis, and one case of expanding hematoma that required segmental hepatic resection, for a total of eight complications in 54 percutaneous transhepatic transplantations of islet cells performed with fluoroscopic guidance alone. Two accidental gallbladder punctures, without complications, are also mentioned. In a more recent study by the same group (26), biliary system puncture did not occur in the 17 of 68 cases in which US was used for localization or guidance.
Traditional portal vein puncture with fluoroscopic guidance and without US guidance incurs an increased risk of puncture of the gallbladder or hepatic arteries or veins, all of which can be accurately visualized and avoided with US guidance. In successful portal vein puncture with fluoroscopic guidance, portal vein catheterization is performed with a 4–6-F catheter. It is unknown what structures the catheter crosses in the intrahepatic tract before it reaches the portal vein. If an artery is crossed, an arteriovenous fistula that is not visible with portography may form after catheter removal at the end of the procedure. Immediately after the procedure, evaluation with color Doppler US is therefore useful to check for signs of bleeding or portal vein thrombosis, as well as arterio–portal venous fistulas or other intrahepatic anomalies, near the site of portal vein puncture.
In the present study, among 58 procedures performed with combined US and fluoroscopic guidance, there were two occurrences of bleeding, one of hemoperitoneum (spontaneously resolved), and one of hemothorax (requiring transfusions and pleural drainage). Intrahepatic tract embolization was not routinely performed and was necessary in fewer than one-third of the patients for persistent bleeding during catheter retraction. The use of a small (4-F) catheter may reduce the need for embolization procedures at the end of transplantation and the risk of hemorrhage.
Heparin administered during the procedure and for 7 days after islet cell transplantation, and long-term aspirin therapy in diabetic patients before transplantation, may increase the risk of bleeding but reduce the incidence of thrombosis.
The risk of bleeding is reduced if portal vein puncture is performed with US guidance by using a 4-F catheter and with embolization of the intrahepatic tract when necessary, even if aspirin or heparin administration is continued.
Intraportal thrombosis is a possible complication of pancreatic islet cell transplantation (25) and may result from various factors (27). Sterility and a high level of purity of the islet cell suspension can simultaneously reduce both thrombosis incidence and the immunogenicity of the graft (17), thus increasing the percentage of successful transplantations (28).
In our opinion, the performance of percutaneous transhepatic transplantation of pancreatic islet cells in an angiographic suite by experienced radiologists who are fully trained in US and interventional radiology is the best method for reducing the mean duration of the procedure and the number of complications. Furthermore, any complications can be managed without patient displacement if the entire procedure is performed in an angiographic suite.
Therapeutic Efficacy
Among uremic type 1 diabetic patients who must regularly undergo hemodialysis, survival is extremely poor, mainly because of cardiovascular complications (29), while life expectancy can double after transplantation of kidney and pancreas (30,31). Survival among patients with functioning pancreatic islet cell transplants is similar to that among patients who have received kidney and pancreas transplants (30,31). The beneficial effects of pancreatic islet cell transplantation on micro- and macrovascular complications have also been described recently (32).
Diabetic and uremic patients who underwent pancreatic islet cell transplantation in our study or in previous studies of combined islet cell and kidney transplantation continued to receive immunosuppressive therapy (cyclosporine, azathioprine, mycophenolate mofetil, methylprednisolone) to prevent rejection of the transplanted kidney and avoid the associated increase in risks of infection and malignancy.
The aim of pancreatic islet cell transplantation in patients with type 1 diabetes is insulin independence or maintenance of good metabolic control (8), with resultant prevention or reversal of complications of diabetes such as nephropathy, retinopathy, neuropathy, cardiopathy, and skeletal disorders. After the first successful transplantation was reported in 1989 (33), several programs for pancreatic islet cell transplantation were developed. Complete insulin independence, however, was achieved in only a minority of patients, often for only a few months (34,35).
In the present study, 12 (35%) of 34 patients maintained insulin independence for more than 3 months (a mean of about 21 months) with full pancreatic islet cell function. Despite a slight reduction of glycated hemoglobin, a sustained C peptide release and exogenous insulin requirement reduction in the follow-up period were suggestive of islet cell function. C peptide levels of more than 0.5 ng/mL were found in almost 50% of the patients at 6 years of follow-up, a sign of well-functioning pancreatic islet cells and improved glycemic control. Reestablishment of C peptide secretion could have a positive effect on microvascular complications of diabetes (32) and prevent diabetic nephropathy. Furthermore, it was previously demonstrated that the achievement of partial islet cell function determines the normalization of protein and lipid homeostasis (10). Reduction in the exogenous insulin requirement suggests an improvement in insulin resistance or a reestablishment of endogenous insulin secretion due to hepatic implantation of pancreatic islet cells.
Hepatic implantation of insulin-producing cells after pancreatic islet cell transplantation was previously demonstrated in human liver specimens obtained at autopsy (36). Histologic analysis of these liver specimens showed well-preserved pancreatic islet cells implanted in the portal spaces, surrounded by hepatocytes and Kupffer cells, and evidence of insulin-positive ß cells was found with immunocytochemical analysis.
Insulin-producing cells in the liver were previously visualized in vivo with both MR imaging and US as a rim of hepatic steatosis surrounding insulinoma metastases (37). A liver biopsy specimen obtained in a patient who underwent pancreatic islet cell transplantation, in whom US showed areas of increased echogenicity, showed evidence of microvesicular steatosis (38). More recently, periportal steatosis was demonstrated with MR imaging by Markmann et al after intraportal islet transplantation (39). In two of four cases periportal steatosis was related to a good islet function; in the other two cases absence of steatosis was related to the degree of transplanted islet cell function.
Massive accumulation of fat in hepatocytes surrounding the islets of Langerhans, which could explain the steatosis evidence, has been demonstrated after islet transplantation in diabetic rats (40,41).
In the present study, hyperechoic parenchymal changes that were not detected at preprocedural evaluation were demonstrated at follow-up US in 12 patients. We attempted to establish whether a correlation existed between hyperechoic parenchymal areas and pancreatic islet cell vitality. From our preliminary data, the change in liver echotexture seems to be related to partial islet cell function (C peptide level, 1.13–2.74 ng/mL). In patients with full or lost function (C peptide level, 0.03–5.30 ng/mL), hyperechoic parenchymal changes were not detectable with US. Hyperechoic parenchymal areas may be related to focal steatosis, which is probably caused by a high insulin concentration due to a few hyperfunctioning pancreatic islet cells. Where loss of function of some cells occurs, the remaining vital cells are probably stimulated to increase insulin production. Further studies that include histologic assessments of liver are necessary to confirm this hypothesis.
In conclusion, although the results of this retrospective study are based on findings in a limited number of patients, percutaneous intrahepatic transplantation of pancreatic islet cells with combined US and fluoroscopic guidance can be considered a safe procedure with a low rate of complications. Color Doppler US has important uses in human pancreatic islet cell transplantation, for the following purposes: preprocedural evaluation, guidance during portal vein puncture, early diagnosis of complications, and, in some cases, postprocedural assessment of hepatic implantation of pancreatic islet cells.
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FOOTNOTES |
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Author contributions: Guarantors of integrity of entire study, M.V., E.A., P.M., A.S., A.D.M.; study concepts, M.V., E.A., F.B., F.D.C.; study design, M.V.; literature research, M.V., C.L.; clinical studies, M.V., E.A., M.S., F.D.C.; data acquisition, P.M., P.F., L.A., C.S.; data analysis/interpretation, P.M., P.F., A.S.; statistical analysis, P.F.; manuscript preparation, M.V.; manuscript definition of intellectual content, V.D.C., A.S., A.D.M.; manuscript editing, M.V., F.D.C.; manuscript revision/review, M.V., E.A., F.D.C.; manuscript final version approval, M.V., A.D.M.
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSION REFERENCES |
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