Can endoscopic ultrasound or magnetic resonance cholangiopancreatography replace ERCP in patients with suspected biliary disease? A prospective trial and cost analysis.

OBJECTIVES: ERCP is the gold standard for pancreaticobiliary evaluation but is associated with complications. Less invasive diagnostic alternatives with similar capabilities may be cost-effective, particularly in situations involving low prevalence of disease. The aim of this study was to compare the performance of endoscopic ultrasound (EUS) with magnetic resonance cholangiopancreatography (MRCP) and ERCP in the same patients with suspected extrahepatic biliary disease. The economic outcomes of EUS-, MRCP-, and ERCP-based diagnostic strategies were evaluated. METHODS: Prospective cohort study of patients referred for ERCP with suspected biliary disease. MRCP and EUS were performed within 24 h before ERCP. The investigators were blinded to the results of the alternative imaging studies. A cost-utility analysis was performed for initial ERCP, MRCP, and EUS strategies for these patients. RESULTS: A total of 30 patients were studied. ERCP cholangiogram failed in one patient, and another patient did not complete MRCP because of claustrophobia. The final diagnoses (N = 28) were CBD stone (mean = 4 mm; range = 3-6 mm) in five patients; biliary stricture in three patients, and normal biliary tree in 20. Two patients had pancreatitis after therapeutic ERCP, one after precut sphincterotomy followed by a normal cholangiogram. EUS was more sensitive than MRCP in the detection of choledocolithiasis (80% vs 40%), with similar specificity. MRCP had a poor specificity and positive predictive value for the diagnosis of biliary stricture (76%/25%) compared to EUS (100%/100%), with similar sensitivity. The overall accuracy of MRCP for any abnormality was 61% (95% CI = 0.41-0.78) compared to 89% (CI = 0.72-0.98) for EUS. Among those patients with a normal biliary tree, the proportion correctly identified with each test was 95% for EUS and 65% for MRCP (p < 0.02). The cost for each strategy per patient evaluated was $1346 for ERCP, $1111 for EUS, and $1145 for MRCP. CONCLUSIONS: In this patient population with a low disease prevalence, EUS was superior to MRCP for choledocholithiasis. EUS was most useful for confirming a normal biliary tree and should be considered a low-risk alternative to ERCP. Although MRCP had the lowest procedural reimbursement, the initial EUS strategy had the greatest cost-utility by avoiding unnecessary ERCP examinations.

Assessment of the clinical utility of the rim and comet-tail signs in differentiating ureteral stones from phleboliths.

OBJECTIVE: This study was designed to assess interobserver variability in identifying the rim and comet-tail signs and to determine the clinical utility of these signs in determining whether or not the calcifications with which they are associated represent ureteral calculi. MATERIALS AND METHODS: Two radiologists and a radiology resident, unaware of the final diagnosis, reviewed preselected helical CT images from renal stone examinations in patients with 65 indeterminate pelvic calcifications. Assessment of calcifications for rim or comet-tail signs was performed independently of an assessment for the following five secondary signs of urinary tract obstruction: caliectasis, pelviectasis, ureterectasis, perinephric stranding, and renal enlargement. Agreement in identifying rim and comet-tail signs was assessed by obtaining kappa statistics. The utility the of rim or comet-tail signs in determining whether ureterolithiasis was present in patients in whom perinephric stranding and ureterectasis were present or absent was determined. The frequency with which one or more of each of the five assessed secondary signs was identified ipsilateral to a calcification having rim or comet-tail signs was also tabulated. RESULTS: Kappa values for interobserver agreement ranged from 0.49 to 0.73. In only one patient was a rim sign detected in the absence of ureterectasis and perinephric stranding. Reviewers identified at least three of the five assessed secondary signs ipsilateral to calcifications showing a rim sign in all but one patient (by each radiologist) and four patients (by the resident). When three or more secondary signs of obstruction were seen ipsilateral to a calcification having a comet-tail sign, in all but one instance, this was because the calcification was a ureteral calculus or because there was a separate ipsilateral ureteral calculus. CONCLUSION: In many instances, observers did not agree about whether the rim and comet-tail signs were present. The rim sign was observed in the absence of any secondary signs of urinary tract obstruction in only one (1.5%) of the 65 patients in our series (95% confidence interval, 0-5.3%). The comet-tail sign, when accompanied by secondary signs of obstruction, should indicate that an ipsilateral ureteral stone is present and not the reverse.

The accuracy of EUS and helical CT in the assessment of vascular invasion by peripapillary malignancy.

BACKGROUND: The relative accuracy of helical CT and EUS for defining the local resectability of peripapillary malignancies is undefined. METHODS: Fifty-one patients with a peripapillary malignancy and no metastatic disease were prospectively evaluated with helical CT and EUS. Imaging results were compared with surgical staging, and a tumor was defined as resectable when there was no macroscopic or microscopic residual tumor. RESULTS: Nine patients had surgically confirmed locally unresectable disease, which was accurately predicted by EUS in 6 patients (sensitivity 67%) and by helical CT in 3 patients (sensitivity 33%; p = 0.35). When only patients with complete EUS examinations were included, the sensitivities of EUS and helical CT for vascular invasion were 100% and 33% (p = 0.06), respectively. When all patients not undergoing surgery because of imaging evidence of locally unresectable disease were included, the sensitivities were 100% and 62.5% (p = 0.02), respectively. One of 15 patients with a tumor amenable to surgical resection was labeled as unresectable by EUS but subsequently had a local recurrence of the tumor. The specificities of EUS (93%) and helical CT (100%) were similar. CONCLUSION: EUS is more sensitive than helical CT for detecting vascular invasion by peripapillary malignancies and should be added to staging protocols, particularly when findings on helical CT are equivocal.

Diagnostic evaluation of the adrenal incidentaloma: decision and cost-effectiveness analyses.

UNLABELLED: The goal of this study was to examine the clinical and economic outcomes of alternative diagnostic strategies for differentiating benign from malignant adrenal masses. METHODS: We used cost-effectiveness assessment derived from decision analysis and the economic perspective of the payer of health care services. One-time evaluation with fine-needle aspiration (FNA) and combinations of chemical-shift MRI, noncontrast CT, 131I-6beta-iodomethylnorcholesterol (NP-59) scintigraphy, with or without FNA, in a hypothetical cohort of 1000 patients with incidentally discovered unilateral, nonhypersecretory adrenal masses. We calculated and compared the diagnostic effectiveness, costs and cost-effectiveness of the alternative strategies based on estimates from published literature and institutional charge data. RESULTS: At an assumed baseline malignancy rate of 0.25, diagnostic utility varied from 0.31 (CT0) to 0.965 (NP-59) and diagnostic accuracy from 0.655 [noncontrast CT using a cut-off attenuation value of > or = 0 (CT0)] to 0.983 (NP-59). The average cost per patient per strategy ranged from $746 (NP-59) to $1745 (MRI +/- FNA). The best and worst potential cost-to-diagnostic utility ratios were 773 (NP-59) and 2839 (CT0) and 759 (NP-59) and 1982 (MRI +/- FNA) for cost and diagnostic accuracy, respectively. The NP-59 strategy was the optimal choice regardless of the expected outcome examined: cost, diagnostic utility, diagnostic accuracy or cost-effectiveness. Varying the prevalence of malignancy did not alter the cost-effectiveness advantage of NP-59 over the other diagnostic modalities. CONCLUSION: Based on available estimates of reimbursement costs and diagnostic test performance and using reasonable clinical assumptions, our results indicate that the NP-59 strategy is the most cost-effective diagnostic tool for evaluating adrenal incidentalomas over a wide range of malignancy rates and that additional clinical studies are warranted to confirm this cost-effectiveness advantage.

Renal masses: assessment of corticomedullary-phase and nephrographic-phase CT scans.

PURPOSE: To evaluate the role of thin-section helical computed tomography (CT) performed during the corticomedullary phase (CMP) and nephrographic phase (NP) of contrast enhancement in the detection and characterization of renal masses. MATERIALS AND METHODS: Renal CT scans and medical records of 33 patients were retrospectively reviewed. In all examinations, 5-mm-thick, contiguous, helical-mode scans were obtained before and 40 seconds after initiation of dynamic bolus injection of contrast material (CMP images); 5-mm-thick, contiguous, axial-mode scans were obtained after completion of CMP scanning (NP images). RESULTS: At review of CMP, NP, and combination images, 259, 389, and 417 lesions, respectively, were identified. The greatest difference in detection occurred in the renal medulla, with 25 lesions identified on CMP images and 111 lesions identified on NP images. False-positive results occurred when CMP images were reviewed without NP images. CONCLUSION: CT scans obtained only during the CMP of contrast enhancement fail to depict many renal masses that are easily seen on NP images.

Initial assessment of positron emission tomography using 2-fluorine-18-fluoro-2-deoxy-D-glucose in the imaging of malignant melanoma.

To assess the feasibility and accuracy of positron emission tomography (PET) in the detection of metastatic malignant melanoma, the authors studied 12 patients approximately 1 hr following a 10-mCi injection of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG). Scan findings were compared to physical examination, imaging and biopsy results. For intra-abdominal visceral and lymph node metastases, the sensitivity of FDG-PET was 100% (15/15). PET also identified three metastatic foci noted only retrospectively on CT, and two metastatic foci seen only on follow-up CT several months later. Eight additional intense foci of FDG uptake that were seen on PET have not yet been confirmed as tumors. In superficial lymph nodes, PET correctly identified seven of seven metastatic lesions (including three cases involving normal-sized lymph nodes) and correctly predicted the absence of tumor in six of six lymph node regions, for an overall accuracy of 100% (13/13). The sensitivity of the PET technique for detecting small pulmonary lesions was lower than CT but this could be due to respiratory motion or prior cancer treatment. This initial experience demonstrates the feasibility and clinical potential of FDG-PET for the detection of regional and systemically metastatic malignant melanoma, particularly in extra-pulmonary lesions.