Clinical role of (18)F-FDG PET for initial staging of patients with extrahepatic bile duct cancer

In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography ((18)F-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both (18)F-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while (18)F-FDG PET revealed increased (18)F-FDG uptake in 18 (60%) of them. On the other hand, (18)F-FDG PET showed focal accumulation of (18)F-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of (18)F-FDG PET were 38%, 100% and 73%, respectively. The specificity of (18)F-FDG PET for regional lymph node metastases was significantly higher than that of CT ( P<0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, (18)F-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, (18)F-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.     

Helical CT cholangiography for the detection and localization of bile duct leakage.

OBJECTIVE: We describe the use of helical CT cholangiography or helical CT after administration of biliary i.v. contrast material to verify and localize bile duct leakage. CONCLUSION: Helical CT cholangiography revealed bile leaks in seven patients after penetrating trauma or liver or gallbladder surgery and excluded bile leaks in two patients with blunt liver trauma. Endoscopic retrograde cholangiography was performed in only one of seven patients with bile leakage and was avoided in an additional two patients in whom CT cholangiography excluded leakage. The method is a feasible, noninvasive tool for the detection and localization of bile leaks and may help avoid endoscopic retrograde cholangiography.     

胆管癌误诊和漏诊的影像学分析

目的：分析胆管癌误诊和漏诊的原因，评价不同检查方法对肝门区胆管癌诊断的价值，提高胆管癌的影像学诊断和鉴别诊断水平。方法：收集31例临床和病理诊断为胆管癌的病例(ERCP检查31例，B超检查31例，25例CT检查，11例行MRCP检查)，回顾性分析不同检查方法的影像学表现。结果：31例中发生在肝门区的胆管癌25例。2例初次ERCP显示胆管内出血，再次行鼻胆管造影后诊断为胆管癌，4例合并有总胆管结石。6例为总胆管中下段癌。初次诊断准确性为90．3％。11例MRCP中9例显示病变，2例显示不满意，7例显示胆管或胆囊结石。25例CT中23例显示肝内胆管扩张，9例显示肝门区肿块，2例见后腹膜转移淋巴结，1例见肝内多发性转移瘤。12例初次诊断正确(48％)。B超检查23例提示肝内胆管扩张，6例提示总胆管结石，18例诊断为胆囊炎、胆囊结石，8例提示胆管占位(25．8％)。结论：良好的直接胆管造影是诊断胆管癌的金标准，MRCP可以在一定程度上准确显示病变的范围，是ERCP的良好补充，很大程度上取代了诊断性ERCP；CT诊断的关键在于显示扩张的胆管和梗阻的定位，肝门区梗阻多为胆管癌所致。多种影像检查方法的结合明显提高了诊断的准确性，对胆管癌治疗方案的选择有重要价值。     

Differentiation of extrahepatic bile duct cholangiocarcinoma from benign stricture: findings at MRCP versus ERCP

PURPOSE: To retrospectively evaluate criteria for differentiating extrahepatic bile duct cholangiocarcinoma from benign cause of stricture at magnetic resonance cholangiopancreatography (MRCP) and to compare diagnostic accuracy with this modality versus endoscopic retrograde cholangiopancreatography (ERCP). MATERIALS AND METHODS: MRCP and ERCP images in 50 patients (27 with cholangiocarcinoma [18 men, nine women; mean age, 58 years] and 23 with benign cause of stricture [13 men, 10 women; mean age, 60 years]) were retrospectively reviewed to assess the appearance of bile duct strictures. Final diagnosis was based on surgical or biopsy findings. Strictures were described according to their imaging appearance (irregular or smooth margins, asymmetric or symmetric narrowing, abrupt narrowing or gradual tapering, and presence or absence of double-duct sign). Sensitivity, specificity, and accuracy of MRCP and ERCP were calculated by using ratings of confidence in image-based diagnosis. Lengths of stricture were electronically measured and compared by using the Student t test. RESULTS: Among cholangiographic criteria for malignant biliary stricture, irregular margins and asymmetric narrowing were more common in cholangiocarcinomas (24 [89%] of 27 patients) than in benign strictures (six [26%] and eight [35%] of 23 patients, respectively). Sensitivity, specificity, and accuracy of the two methods for differentiation of malignant from benign causes of biliary stricture were 81% (22 of 27), 70% (16 of 23), and 76% (38 of 50), respectively, for MRCP and 74% (20 of 27), 70% (16 of 23), and 72% (36 of 50), respectively, for ERCP. Mean length (+/- standard deviation) of cholangiocarcinomas was 30.0 mm +/- 8.5, and that of benign strictures was 13.6 mm +/- 9.1 (P <.001). CONCLUSION: Accuracy of MRCP is comparable with that of ERCP. Regardless of modality, a lengthy segment of extrahepatic bile duct stricture with irregular margin and asymmetric narrowing suggests cholangiocarcinoma, and a short segment with regular margin and symmetric narrowing suggests benign cause.     

Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterization.

In this retrospective study, we investigated whether the (18)F-FDG uptake pattern and CT findings improved the accuracy over the standardized uptake value (SUV) for differentiating benign from malignant focal thyroid lesions incidentally found on (18)F-FDG PET/CT. We also defined the prevalence of these lesions and their risk for cancer. METHODS: (18)F-FDG PET/CT was performed on 1,763 subjects without a previous history of thyroid cancer from May 2003 to June 2004. Two nuclear medicine physicians and 1 radiologist interpreted PET/CT images, concentrating on the presence of focal thyroid lesions, the maximum SUV of the thyroid lesion, the pattern of background thyroid (18)F-FDG uptake, and the CT attenuation pattern of the thyroid lesion. RESULTS: The prevalence of focal thyroid lesions on PET/CT was 4.0% (70/1,763). Diagnostic confirmation was done on 44 subjects by ultrasonography (US)-guided fine-needle aspiration (n = 29) or US with clinical follow-up (n = 15). Among 49 focal thyroid lesions in these 44 subjects, 18 focal thyroid lesions of 17 subjects were histologically proven to be malignant (papillary cancer in 16, metastasis from esophageal cancer in 1, non-Hodgkin's lymphoma in 1). Therefore, the cancer risk of focal thyroid lesions was 36.7% on a lesion-by-lesion basis or 38.6% on a subject-by-subject basis. The maximum SUV of malignant thyroid lesions was significantly higher than that of benign lesions (6.7 +/- 5.5 vs. 10.7 +/- 7.8; P < 0.05). When only the maximum SUV was applied to differentiate benign from malignant focal thyroid lesions for the receiver-operating-characteristic curve analysis, the area under the curve (AUC) of PET was 0.701. All 16 focal thyroid lesions with very low attenuation or nonlocalization on CT images, or with accompanying diffusely increased thyroid (18)F-FDG uptake, were benign. When those lesions were regarded as benign lesions, irrespective of the maximum SUV, the AUC of PET/CT was significantly improved to 0.878 (P < 0.01). CONCLUSION: Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Image interpretation that includes (18)F-FDG uptake and the CT attenuation pattern, along with the SUV, significantly improves the accuracy of PET/CT for differentiating benign from malignant focal thyroid lesions.     

Usefulness of Respiratory-Gated <Superscript>18</Superscript>F-FDG PET/CT in Detecting Upper Abdominal Fever Focus

Respiratory-gated ¹⁸F-fluorodeoxygluocse (¹⁸F-FDG) PET/CT has been successfully used to better localize malignancies in the lung or upper abdominal organs. However, clinical usefulness of respiratory-gated ¹⁸F-FDG PET/CT in detection of fever focus has not been reported yet. A 68-year-old male patient with a history of living donor liver transplantation and biliary stenting was referred for ¹⁸F-FDG PET/CT due to fever of unknown origin (FUO). To find the accurate fever focus, respiratory-gated and non-gated ¹⁸F-FDG PET/CT was performed. Respiratory-gated PET/CT readily revealed prominent hypermetabolic lesion in the distal common bile duct (CBD) area where previous surgical graft was in situ. Maximum standardized uptake value (SUVmax) and SUV ratio (SUR) were greater in the gated PET/CT (SUVmax 5.4 and SUR 3.5) than in the non-gated PET/CT (SUVmax 4.6 and SUR 3.0). Fever dramatically subsided after removal of the graft in the CBD. This case report implies that respiratory-gated ¹⁸F-FDG PET/CT can visualize upper abdominal fever focus with better contrast than the conventional non-gated method.     

Cholangiographic findings in ulcerative colitis

Endoscopic retrograde cholangiography (ERC) was performed in 28 patients with hepatobiliary disease associated with ulcerative colitis. The films were reviewed and correlated with diagnoses at liver biopsy. Thirteen patients with extrahepatic as well as intrahepatic bile duct abnormalities had characteristic cholangiographic findings compatible with sclerosing cholangitis, together with cholangiocarcinoma in one patient. Six patients had intrahepatic bile duct involvement only, and the cholangiographic abnormalities differed from those of sclerosing cholangitis. In 5 of these patients cirrhosis of the liver was found at biopsy or clinically. The result indicates that in patients with hepatobiliary disease suggested in association with ulcerative colitis, ERC gives valuable information.     

口服法螺旋CT胆管造影临床应用价值探讨

目的探讨口服法螺旋CT胆管造影对胆系疾病的诊断价值和对胆系手术的指导价值。方法可疑胆系病变患者18例。服用碘番酸后12~14h行CT扫描,并行2D、3DMIP重建。据碘番酸剂量分大剂量组(6.0g)5例,中剂量组(3.0g)10例和小剂量组(1.0g)3例。显影程度分未显影、轻度显影、良好显影和过度显影4级。造影结果与病理和/或临床结果对照。结果(1)胆管显影与碘番酸剂量有关。观察肝内胆管用量不应<6.0g,观察肝总管和胆总管3.0g基本满足要求。(2)口服法螺旋CT胆管造影可显示肝内外胆管特别是肝外胆管的解剖结构,反映胆系功能和其通畅情况以及病变与胆管之间的关系,对胆囊阴性结石和胆囊息肉诊断的敏感度为80%,对胆总管阴性结石诊断的敏感度为88.89%,特异度为100%。(3)2D和3DMIP重建空间感好,是原始图像的重要补充。结论口服法螺旋CT胆管造影简便、无创,是显示肝内外胆管解剖结构和诊断胆系病变的一种较好方法,对胆系手术有指导作用。     

Using contrast-enhanced MR cholangiography with IV mangafodipir trisodium (Teslascan) to evaluate bile duct leaks after cholecystectomy: a prospective study of 11 patients

OBJECTIVE: The purpose of our study was to determine whether contrast-enhanced MR cholangiography using IV mangafodipir trisodium can accurately detect the presence and location of bile duct leaks in patients who have undergone cholecystectomy. SUBJECTS AND METHODS: Our study group included 11 patients with suspected bile duct leaks after cholecystectomy. Axial single-shot fast spin-echo and gradient-echo images were acquired in all patients before and 1-2 hr after IV administration of mangafodipir trisodium. The contrast-enhanced MR cholangiograms were evaluated for image quality, degree of ductal or small bowel opacification, and the presence and location of bile duct leaks, strictures, and stones. MR cholangiograms were correlated with conventional contrast-enhanced cholangiograms obtained in all patients, including endoscopic retrograde cholangiography (n = 10) and percutaneous transhepatic cholangiography (n = 1). RESULTS: Excretion of mangafodipir trisodium was noted in the intrahepatic and extrahepatic bile ducts in all patients from 1 to 2 hr after IV administration. Bile ducts and fluid collections that contained excreted mangafodipir trisodium showed increased signal intensity on gradient-echo sequences and decreased signal intensity on single-shot fast spin-echo sequences. Conventional contrast-enhanced cholangiography showed the presence of bile duct leaks in six patients and the absence of bile duct leaks in five patients, with false-negative findings in one patient and false-positive findings in one patient for bile duct leak (sensitivity, 86%; specificity, 83%). CONCLUSION: Contrast-enhanced MR cholangiography with IV mangafodipir trisodium can successfully detect the presence and location of bile duct leaks in patients suspected of having such leaks after undergoing cholecystectomy. More research is necessary before acceptance of this examination as routine in the workup of these patients.     

Dual-time-point 18F-FDG PET for the evaluation of gallbladder carcinoma.

Conventional imaging techniques such as ultrasonography, CT, and MRI are able to detect gallbladder abnormalities but are not always able to differentiate a malignancy from other disease processes such as cholecystitis. The purpose of the present study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for differentiating malignant from benign gallbladder disease. METHODS: The study evaluated 32 patients who were suspected of having gallbladder tumors. (18)F-FDG PET (whole body) was performed at 62 +/- 8 min (early) after (18)F-FDG injection and was repeated 146 +/- 14 min (delayed) after injection only in the abdominal region. We evaluated the (18)F-FDG uptake both visually and semiquantitatively. Semiquantitative analysis using the standardized uptake value (SUV) was performed for both early and delayed images (SUV(early) and SUV(delayed), respectively). The retention index (RI) was calculated according to the equation (SUV(delayed) - SUV(early)) x 100/SUV(early). The tumor-to-liver ratio was also calculated. Results: The final diagnosis was gallbladder carcinoma in 23 patients and benign disease in 9 patients. For visual analysis of gallbladder carcinoma, delayed (18)F-FDG PET images improved the specificity of diagnosis in 2 patients. When an SUV(early) of 4.5, SUV(delayed) of 2.9, and RI of -8 were chosen as arbitrary cutoffs for differentiating between malignant and benign conditions, sensitivity increased from 82.6% to 95.7% and 100% for delayed imaging and combined early and delayed imaging (i.e., RI), respectively. With the same criteria, specificity decreased from 55.6% to 44.4% for delayed imaging and combined early and delayed imaging, respectively. The specificity of (18)F-FDG PET improved to 80% in the group with a normal level of C-reactive protein (CRP) and decreased to 0% in the group with an elevated CRP level. For gallbladder carcinoma, both SUV and tumor-to-liver ratios derived from delayed images were significantly higher than the ratios derived from early images (P < 0.0001). CONCLUSION: Delayed (18)F-FDG PET is more helpful than early (18)F-FDG PET for evaluating malignant lesions because of increased lesion uptake and increased lesion-to-background contrast. However, the diagnostic performance of (18)F-FDG PET depends on CRP levels.     

Characterization of the normal adrenal gland with 18F-FDG PET/CT.

Prior studies have documented increased (18)F-FDG adrenal activity in both benign and malignant pathologic conditions. When whole-body PET imaging is performed without CT anatomic coregistration, however, the normal adrenal gland is difficult to recognize. The purpose of this study was to investigate the normal adrenal appearance and standardized uptake value (SUV) using (18)F-FDG PET/CT imaging. METHODS: Twenty patients with lymphoma with normal-appearing adrenal glands on prior CT examination (less than a 5% pretest likelihood of adrenal involvement) were studied. PET/CT imaging was performed 2 h after intravenous administration of (18)F-FDG. Unenhanced CT scans were acquired for attenuation correction and anatomic coregistration. PET images were reconstructed using an ordered-subsets expectation maximization algorithm and were corrected for body weight, dose, and radioactive decay. Ability to confirm visualization of the adrenal glands was determined for (18)F-FDG PET alone and for (18)F-FDG PET/CT by a consensus of 2 readers, and uptake of (18)F-FDG in the adrenal gland was compared with liver activity and scored visually (0 = no visualization, 1 = activity less than in liver, 2 = activity equal to liver activity, and 3 = activity greater than in liver). RESULTS: The 2 readers agreed on visualization of the adrenal glands with PET alone for 2 of 40 (5%) glands. With PET/CT, the readers agreed on visualization of 27 of 40 (68%) adrenal glands. Visual scores for normal adrenal activity ranged from 0 to 3, and maximum SUVs ranged from 0.95 to 2.46. Visual scoring of adrenal activity correlated well with both mean and maximal SUV (mean SUV vs. visual score: slope = 0.96, r = 0.88; maximum SUV vs. visual score: slope = 0.99, r = 0.87). CONCLUSION: PET/CT permits more reliable visualization of normal adrenal glands than does PET alone. Visual assessment of adrenal uptake correlates well with SUV measurement, and readers of PET/CT need to be aware of the wide range of normal adrenal uptake.     

Diagnostic and interventional procedures for the biliary tract

Various diagnostic imaging studies have been employed in the past year to evaluate the normal and abnormal biliary ductal system. Variations in the normal ductal drainage of the left lobe of the liver, in which the right lateral hepatic duct drained into the left hepatic duct, were studied because of the implications for the surgical resection of the left lobe. Choledochal cysts have been studied in adults using endoscopic retrograde cholangiopancreatography to evaluate the abnormal junction between the common bile duct and pancreatic duct and the long dilated common channel. An ultrasound study indicated that children with choledochal cysts also may have intrahepatic duct dilatation. An increased incidence of malignancy has been noted in adults with choledochal cysts, and their appearance on ultrasound, CT, and cholangiography were described. Cystic fibrosis produces abnormalities of the biliary tree, extrahepatic strictures, and more interestingly, intrahepatic ductal dilatation and abnormal contour without strictures. The usefulness of the preoperative ultrasonographic evaluation of the biliary tract in Oriental cholangiohepatitis was stressed. Bile duct abnormalities in fascioliasis were also noted on CT scans. Patterns of abnormality in the CT appearance of the thickened, contrast-enhanced, extrahepatic bile ducts were elucidated. Focal concentric, focal excentric, diffuse concentric, and diffuse excentric ducts were seen with various forms of pancreatic disease, choledocholithiasis, and various forms of cholangitis. An enhanced, thick-walled duct indicates disease, but is a nonspecific finding. Chronic cholecystitis was found to produce false-positive cholescintigram results in patients with suspected acute cholecystitis, but only in those with severe degrees of chronic cholecystitis. The results of multicenter trials using extracorporeal biliary lithotripsy in the United States have been published. They are somewhat disappointing and do not confirm the original excellent results reported in Germany for treatment of gallbladder stones. Much interest has been focused on the use of expandable metallic stents for the treatment of benign and malignant biliary obstruction. Preliminary data suggest good patency rates for benign lesions. Patency rates for malignant lesions are similar to those of previously available plastic stents.     

胆管癌的18F-FDG PET/CT诊断价值

目的 总结胆管癌18F-FDG PET/CT显像表现,提高胆管癌的诊断准确性.方法 回顾经病理或临床综合手段证实的53例胆道疾病的18F-FDG PET/CT表现,分析PET/CT诊断胆管癌的敏感性、特异性和准确性.结果 肝内胆管癌14例、近段胆管癌18例、中远段胆总管癌15例、胆管炎性病变或伴结石6例.肝内转移9例,腹腔及腹膜后淋巴结转移15例,椎体等远处转移3例.PET/CT诊断胆管癌的敏感性为95.7％、特异性为83.3％、准确性为94.3％.结论 18F-FDG PET/CT在胆管癌的诊断与鉴别诊断、分期、检测疗效及预后等具有独特的应用价值.     

Sclerosing cholangitis: CT findings

The value of computed tomography (CT) in the detection of primary sclerosing cholangitis (PSC) in the intrahepatic and extrahepatic biliary systems was assessed by comparing CT scans of 20 cases of PSC with cholangiographic findings. In 16 of 19 cases of extrahepatic duct disease demonstrated with cholangiography, CT demonstrated abnormalities of the common hepatic duct, or bile duct, including duct stenosis, mural nodularity, duct dilatation, wall thickening, and mural enhancement. CT demonstrated intrahepatic disease in all 20 cases, including duct dilatation, duct stenosis, pruning, and beading. CT was superior to cholangiography in characterization of the status of the intrahepatic duct system in 11 of 20 cases. In addition, CT demonstrated extrabiliary complications of PSC in 12 cases and superimposed cholangiocarcinoma in three cases. While cholangiography remains the standard for diagnosis and follow-up of PSC, CT can provide valuable information about the extent and complications of the disease.     

Chemotherapy-induced sclerosing cholangitis

AIM: To review the computed tomography (CT), magnetic resonance imaging (MRI) and cholangiographic findings of chemotherapy-induced sclerosing cholangitis (CISC). METHODS: Between January 1995 and December 2004, 11 patients in the endoscopic retrograde cholangiography database were identified with CISC. Twelve CT, four MRI, 69 endoscopic and nine antegrade cholangiographic studies in these patients were reviewed. Serial change in appearance and response to endoscopic treatment were recorded. RESULTS: CISC showed segmental irregular biliary dilatation with strictures of proximal extrahepatic bile ducts. The distal 5cm of common bile duct was not affected in any patient. CT and MRI findings included altered vascular perfusion of one or more liver segments, liver metastases or peritoneal carcinomatosis. Biliary strictures needed repeated stenting in 10 patients (mean: every 4.7 months). Cirrhosis (n=1) or confluent fibrosis (n=0) were uncommon findings. CONCLUSION: CISC shares similar cholangiographic appearances to primary sclerosing cholangitis (PSC). Unlike PSC, biliary disease primarily involved ducts at the hepatic porta rather than intrahepatic ducts. Multiphasic contrast-enhanced CT or MRI may show evidence of perfusion abnormalities, cavitary liver lesions, or metastatic disease.     

Spatial and temporal heterogeneity of regional myocardial uptake in patients without heart disease under fasting conditions on repeated whole-body 18F-FDG PET/CT.

Imaging of cardiac (18)F-FDG uptake is used in the diagnostic evaluation of residual viable myocardium. Although, originally, hibernating myocardium was identified by a mismatch between perfusion defect and relatively preserved (18)F-FDG uptake, at present several studies propose that (18)F-FDG distribution can also be used alone for this purpose. Nevertheless, even severe myocardial (18)F-FDG uptake defects are frequently observed in cancer patients without any cardiac disease. The aim of this study was to retrospectively analyze global and regional (18)F-FDG cardiac images of 49 consecutive cancer patients free of cardiac diseases who submitted to 3 PET scans under fasting conditions. METHODS: Images were acquired with a high-resolution PET/CT scanner. Three-dimensional regions of interest were drawn on the fused PET/CT images to measure the maximal standardized uptake value of the left ventricular myocardium (SUV(Myo)) as well as the average SUV of the left ventricular blood (SUV(LV)) and of the liver (SUV(Liver)). Analysis of regional myocardial (18)F-FDG uptake was performed on a subsample of 26 patients by an automatic recognition of endocardial and epicardial borders and subdividing the left ventricle in 20 segments. Regional (18)F-FDG distribution was defined as the percentage of SUV(Myo) in each region. RESULTS: SUV(Myo) as well as SUV(LV) and SUV(Liver) did not change on average throughout the studies. This stability was not caused by a persistent pattern of myocardial (18-)FDG distribution. Rather, it was associated with important variations in both directions over time. Regional (18)F-FDG distribution was largely heterogeneous in all 3 studies, with a variation coefficient in each patient of 18% +/- 7%, 18% +/- 5%, and 17% +/- 5%, respectively. An (18)F-FDG uptake of <50% occurred in 78, 102, and 69 of 468 segments, although it disappeared in 55% of instances at subsequent examinations. Regional temporal variability was also marked: The absolute value of the difference in percent uptake was 10.1% +/- 7.3% from test 1 to test 2, 8.0% +/- 7.0% from test 1 to test 3, and 9.2% +/- 6.9% from test 2 to test 3. Overall from one test to another, uptake increased or decreased by >10% in 76 and in 116 of 468 segments, respectively. CONCLUSION: The large spatial and temporal heterogeneity of the myocardial metabolic pattern, in cancer patients free of any disease, suggests a word of caution on the use of (18)F-FDG alone as a diagnostic tool for myocardial viability.     

Normal and abnormal 18F-FDG endometrial and ovarian uptake in pre- and postmenopausal patients: assessment by PET/CT.

The purpose of the study was to assess physiologic endometrial (18)F-FDG uptake during the 4 phases of the menstrual cycle and to differentiate between physiologic and malignant endometrial uptake. METHODS: Endometrial (18)F-FDG uptake, expressed as standardized uptake value (SUV), was measured on PET/CT images of 285 consecutive female patients, of whom 246 (112 premenopausal and 134 postmenopausal) had no known gynecologic malignancy and 39 (14 premenopausal and 25 postmenopausal) had cervical, endometrial, or ovarian cancer. RESULTS: Two peaks of increased endometrial (18)F-FDG uptake were identified during the 4-phase cycle. The mean SUVs were 5 +/- 3.2 and 3.7 +/- 0.9 in menstruating and ovulating patients, respectively, and 2.6 +/- 1.1 and 2.5 +/- 1.1 in patients in the proliferative and secretory phases, respectively. The mean endometrial SUV in postmenopausal patients not receiving hormonal therapy was 1.7 +/- 0.5. Oligomenorrhea and benign endometrial abnormalities were associated with increased (18)F-FDG uptake. Neither contraceptives nor hormonal therapy was associated with a significant increase in endometrial uptake. In addition to the increased tumor uptake measured in patients with cervical cancer (14.9 +/- 7.3 in postmenopausal patients and 12.2 +/- 6.6 in premenopausal patients), increased uptake was also found in the adjacent endometrium, although it appeared normal on CT (4.8 +/- 2 in premenopausal patients and 4.7 +/- 2.8 in postmenopausal patients). Increased ovarian (18)F-FDG uptake was detected in 7 patients with ovarian cancer (9.1 +/- 4) and in 21 premenopausal patients without known ovarian malignancy (5.7 +/- 1.5, P < 0.01), of whom 15 were at mid cycle and 3 reported oligomenorrhea. An ovarian SUV of 7.9 separated benign from malignant uptake with a sensitivity of 57% and a specificity of 95%. CONCLUSION: In premenopausal patients, normal endometrial uptake of (18)F-FDG changes cyclically, increasing during the ovulatory and menstrual phases. Increased uptake in the endometrium adjacent to a cervical tumor does not necessarily reflect endometrial tumor invasion. Increased ovarian uptake in postmenopausal patients is associated with malignancy, whereas increased ovarian uptake may be functional in premenopausal patients.     

Is 18F-3'-fluoro-3'-deoxy-L-thymidine useful for the staging and restaging of non-small cell lung cancer?

The objective of this study was to compare 18F-3'-fluoro-3'-deoxy-L-thymidine (FLT) PET with clinical TNM staging, including that by 18F-FDG PET, in patients with non-small cell lung cancer (NSCLC). METHODS: Patients with NSCLC underwent whole-body 18F-FDG PET and whole-body 18F-FLT PET, using a median of 360 MBq of 18F-FDG (range, 160-500 MBq) and a median of 210 MBq of 18F-FLT (range, 130-420 MBq). 18F-FDG PET was performed 90 min after 18F-FDG injection, and 18F-FLT PET was performed 60 min after 18F-FLT injection. Two viewers independently categorized the localization and intensity of tracer uptake for all lesions. All 18F-FDG PET and 18F-FLT PET lesions were compared. Staging with 18F-FLT PET was compared with clinical TNM staging based on the findings of history, physical examination, bronchoscopy, CT, and 18F-FDG PET. From 8 patients, standardized uptake values (SUVs) were calculated. Maximal SUV and mean SUV were calculated. RESULTS: Sixteen patients with stage IB-IV NSCLC and 1 patient with strong suspicion of NSCLC were investigated. Sensitivity on a lesion-by-lesion basis was 80% for the 8 patients who received treatment before 18F-FLT PET and 27% for the 9 patients who did not receive pretreatment, using 18F-FDG PET as the reference standard. Compared with clinical TNM staging, staging by 18F-FLT PET was correct for 8 of 17 patients: 5 of 9 patients in the group with previous therapy and 3 of 8 patients in the group without previous therapy. The maximal SUV of 18F-FLT PET, at a median of 2.7 and range of 0.8-4.5, was significantly lower than that of 18F-FDG PET, which had a median of 8.0 and range of 3.7-18.8 (n = 8; P = 0.012). The mean SUV of 18F-FLT PET, at a median of 2.7 and range of 1.4-3.3, was significantly lower than that of 18F-FDG PET, which had a median of 6.2 and range of 2.8-13.9 (n = 6; P = 0.027). CONCLUSION: 18F-FLT PET is not useful for staging and restaging NSCLC.     

MR cholangiopancreatography in patients with primary sclerosing cholangitis: interobserver variability and comparison with endoscopic retrograde cholangiopancreatography

OBJECTIVE: The purpose of our study was to determine the degree of interobserver variability and correlation between MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) for the presence of bile duct strictures in patients with primary sclerosing cholangitis. MATERIALS AND METHODS: For this retrospective study involving 26 patients with primary sclerosing cholangitis, 31 MR cholangiopancreatograms were compared with 30 endoscopic retrograde cholangiopancreatograms. The MR cholangiopancreatograms were independently interpreted by two abdominal radiologists in a blinded, randomized manner for overall image quality, extent of ductal visualization, and the presence and location of bile duct strictures. Unweighted multirater kappa coefficient values were estimated for each comparison. RESULTS: Visualization of more than 50% of the expected ductal length was possible in the extrahepatic, central intrahepatic, and peripheral intrahepatic bile ducts in 99%, 88%, and 69% of the MR cholangiopancreatograms and 100%, 86%, and 52% of the endoscopic retrograde cholangiopancreatograms, respectively. Strictures were detected in the extrahepatic, central, and peripheral ducts in 53%, 68%, and 87% of the MR cholangiopancreatograms and 73%, 67%, and 63% of the endoscopic retrograde cholangiopancreatograms, respectively. The interobserver agreement for stricture detection was 61% for MR cholangiopancreatography and 76% for ERCP. MR cholangiopancreatographic findings were consistent with ERCP findings for the presence of strictures in 69% of the cases. CONCLUSION: In patients with primary sclerosing cholangitis, MR cholangiopancreatography better shows the bile ducts and can depict more strictures, especially of the peripheral intrahepatic ducts, than ERCP. MR cholangiopancreatography can be used to noninvasively diagnose and follow up patients with primary sclerosing cholangitis.     

11C-acetate PET imaging in hepatocellular carcinoma and other liver masses.

It is well known that (18)F-FDG PET has a high average false-negative rate of 40%-50% in the detection of hepatocellular carcinoma (HCC). This is not an acceptable accuracy, particularly in countries where this tumor is prevalent. In this study, we evaluated prospectively the characteristics of (11)C-acetate and (18)F-FDG metabolism in HCC and other liver masses. METHODS: Fifty-seven patients were recruited into this study, with masses consisting of 39 HCC; 3 cholangiocarcinomas; 10 hepatic metastases from lung, breast, colon, and carcinoid primary malignancies; and 5 benign pathologies, including focal nodular hyperplasia (FNH), adenoma, and hemangioma. All patients, except 2 with typical findings of hemangioma and 3 clinically obvious metastases, were confirmed histopathologically by liver biopsy or resection. All patients fasted for at least 6 h and blood glucose concentration was measured before they underwent dual PET radiopharmaceutical evaluation of the upper abdomen with (11)C-acetate and (18)F-FDG. RESULTS: In the subgroup of HCC patients with the number of lesions < or = 3 (32 patients; 55 lesions; mean size +/- SD, 3.5 +/- 1.9 cm), the sensitivity of detection by (11)C-acetate is 87.3% ((11)C-acetate maximum SUV [SUV(max)] = 7.32 +/- 2.02, with a lesion-to-normal liver ratio of 1.96 +/- 0.63), whereas the sensitivity of detection by (18)F-FDG is only 47.3%, and 34% lesions show uptake of both tracers. None of the lesions was negative for both tracers (100% sensitivity using both tracers). In some lesions and in the subgroup of HCC patients (n = 7) with multifocal or diffuse disease, dual-tracer uptake by different parts of the tumor is demonstrated. Histopathologic correlation suggests that the well-differentiated HCC tumors are detected by (11)C-acetate and the poorly differentiated types are detected by (18)F-FDG. All 16 non-HCC malignant (cholangiocarcinoma and metastatic) liver lesions do not show abnormal (11)C-acetate metabolism. Of the benign liver lesions, only FNH shows mildly increased (11)C-acetate activities ((11)C-acetate SUV(max) = 3.59, with a lesion-to-normal liver ratio of 1.25). CONCLUSION: (11)C-Acetate has a high sensitivity and specificity as a radiotracer complementary to (18)F-FDG in PET imaging of HCC and evaluation of other liver masses.