Is gadolinium necessary for MRI follow-up evaluation of cystic lesions in the pancreas? Preliminary results.

OBJECTIVE: The purpose of our study was to determine whether gadolinium is necessary in the follow-up evaluation of pancreatic cystic lesions. MATERIALS AND METHODS: Fifty-six patients with pancreatic cystic lesions detected on initial MRI and who underwent follow-up MRI were identified. Mean cyst size was 1.9 cm, and mean follow-up was 9.1 months. MRI included multiacquisition T1- and T2-weighted sequences before contrast administration and 3D fat-suppressed T1-weighted images before and after gadolinium administration. Two radiologists independently reviewed the entire initial examination and follow-up MRI using only unenhanced T1- and T2-weighted sequences from the second examination. Each radiologist made one of three recommendations: 1, no follow-up necessary or follow-up imaging in 6-12 months; 2, cyst aspiration; or 3, cyst resection. Four weeks later, imaging studies were reevaluated with the contrast-enhanced images from the second examination. A second recommendation using the same outcomes was made. Interobserver and intraobserver variations for the same patient were summarized in terms of kappa coefficients and the percentage of times the decisions were concordant. A 95% CI for the percentage of times management decisions would change without and with gadolinium was calculated. RESULTS: Concordance between the two different readers for the interpretations (when using the same MRI interpretation technique for follow-up surveillance) was 87.5% with a kappa coefficient to assess interobserver variation of 0.075, suggesting only slight agreement between the two readers. However, treatment recommendations provided by a single reader with and without information from the contrast-enhanced images were discordant only 4.5% of the time. Recommendations were concordant without and with gadolinium 95.5% (107/112; kappa=0.67) of the time, suggesting substantial agreement. A retrospective consensus review of the five cases in which gadolinium effected a change in the observer's recommendation was performed. There was nothing on the gadolinium-enhanced sequences that would specifically alter a change in a management decision, and it is likely that the changes in management decisions in these five cases were simply related to expected variations in categorizing lesions rather than to the use of gadolinium. CONCLUSION: The use of gadolinium has minimal impact in the follow-up MR assessment of pancreatic cystic lesions.

Outcome of percutaneous surgery stratified according to body mass index and kidney stone size.

OBJECTIVE: To stratify outcome and morbidity of percutaneous nephrostolithotomy (PCNL) with regard to body mass index (BMI) and kidney stone burden. METHODS: The charts of 148 patients who underwent PCNL procedures were reviewed retrospectively. Hospital stay, blood loss, maximal temperature during inpatient stay, and stone-free outcomes were evaluated. Patients were divided into 3 groups depending on their BMIs: <25 kg/m, 25 to 29.9 kg/m, and >30 kg/m. Kidney stone burden was measured in terms of square area in millimeters, as measured by retrospective review of computerized tomography scans. Preoperative computerized tomography scan for measurement of stone burden was available for only 85 patients who are included in the study. Analysis of variance for a single variable was performed with regard to the values of the hospital stay, postoperative maximal temperature, and hemoglobin change. RESULTS: Of the 85 patients, 37 (43.5%) were obese or morbidly obese (BMI, >30 kg/m), 33 (38.8%) were overweight (BMI, 25 to 29.9 kg/m), and 15 (17.7%) were within or below their ideal weight (BMI, <25 kg/m). No statistically significant difference among the 3 groups was seen for stone-free rate, postoperative fever, or change in hemoglobin when stratified by BMI alone or by BMI and kidney stone burden. However, significantly longer length of stay for the group with BMI <25 kg/m was observed when stratifying either by BMI alone (P=0.01) or by BMI and kidney stone burden (P=0.03). CONCLUSIONS: In this retrospective review of patients with kidney stones undergoing PCNL, the stone-free outcome and associated morbidity of PCNL (except for the length of hospital stay) is independent of both patients' BMI and stone burden when stratifying by commonly defined parameters.

Filling defects at CT colonography: pseudo- and diminutive lesions (the good), polyps (the bad), flat lesions, masses, and carcinomas (the ugly).

Numerous filling defects may be detected in the colon during interpretation of data sets obtained with computed tomographic (CT) colonography. A series of 230 patients were evaluated with thin-section multidetector row CT colonography immediately before conventional colonoscopy. In all cases, the interpreting radiologist and gastroenterologist reviewed the imaging findings as well as the results of histologic analysis of biopsy specimens to determine the causes of filling defects. In many cases, the cause of a filling defect can be confidently determined at CT colonography by using combinations of two- and three-dimensional images. However, lesions will occasionally be indeterminate because of overlapping features and will require further evaluation with endoscopy. With knowledge of the morphologic and attenuation characteristics of the various filling defects in the colon, one should be able to differentiate those filling defects detected at CT colonography that require no further evaluation from those that require endoscopic interrogation.

Photocontact allergy to diallyl disulfide.

Although phototoxic reactions to plants are common, photoallergic contact dermatitis to plants and plant products rarely occurs. Our objective was to review the importance of including diallyl disulfide in the evaluation of patients with suspected photosensitivity. Phototests for ultraviolet B, ultraviolet A, and visible light as well as patch tests and photopatch tests for 49 allergens from the New York University Skin and Cancer Unit Photopatch Test Series were performed. Three patients had positive photopatch-test results to diallyl disulfide, which is the allergen in garlic. The authors conclude that although photocontact allergy to diallyl disulfide is rare, this allergen should be included in photopatch-test series.

Significance of missed polyps at CT colonography.

OBJECTIVE: Our purpose was to determine the clinical significance of polyps missed on CT colonography using histologic analysis and the natural history of colorectal polyps and to propose guidelines for follow-up colon surveillance based on CT colonographic findings. SUBJECTS AND METHODS. One hundred eighty-six men (age range, 40-87 years; mean, 62.3 years) underwent CT colonography immediately before conventional colonoscopy. All polyps detected on CT colonography were measured and imaged, and their segmental location was documented. All polyps detected on colonoscopy were measured, photographed, biopsied, and histologically analyzed. Results of CT colonography and conventional colonoscopy were compared with the final pathology reports. Conventional colonoscopy was used as the gold standard unless CT colonography showed a lesion measuring 10 mm or more that was not detected on conventional colonoscopy and had characteristics of a polyp. In these cases, follow-up conventional colonoscopy was offered. RESULTS: One hundred ninety-one polyps were detected on conventional colonoscopy. CT colonography prospectively detected 53 polyps. Histologic analysis of the polyps not detected on CT colonography showed that of those 5 mm or smaller, 58.1% were not adenomas, and of those measuring 6-9 mm, 42.8% were not adenomas. Both missed polyps at CT colonography of 10 mm or more were adenomas. Of the 22 polyps measuring 10 mm or more, three were not detected on conventional colonoscopy. Of these three, CT colonography showed a lesion having characteristics of a polyp, follow-up endoscopy confirmed the presence of the lesion, and histologic analysis showed a villous adenoma, a tubulovillous adenoma, and a tubular adenoma. CONCLUSION: If CT colonography shows no abnormality, follow-up screening in 5 years is recommended. If CT colonography detects a lesion smaller than 5 mm, follow-up imaging in 3-5 years is recommended. If CT colonography detects a lesion measuring 6 mm or more, endoscopy and polypectomy should be offered unless contraindicated.

Colorectal polyps and cancers in asymptomatic average-risk patients: evaluation with CT colonography.

PURPOSE: To compare thin-section multi-detector row computed tomographic (CT) colonography with conventional colonoscopy in the evaluation of colorectal polyps and cancer in asymptomatic average-risk patients. MATERIALS AND METHODS: Sixty-eight asymptomatic men (age > 50 years) scheduled to undergo screening colonoscopy were enrolled in this study. CT colonography was followed by conventional colonoscopy, performed on the same day. Supine and prone CT colonography were performed after colonic insufflation with room air. A gastroenterologist measured all polyps, which were categorized as 1-5, 6-9, or over 10 mm. Biopsy and histologic evaluation were performed of all polyps. CT colonography and colonoscopy results were compared for location, size, and morphology of detected lesions. Point estimates and 95% CIs were provided for specificity and sensitivity of CT by using results at conventional colonoscopy as the reference standard. RESULTS: At colonoscopy, 98 polyps were identified in 39 patients; 21 (21.4%) of 98 were detected at CT colonography. Sensitivity was 11.5% (nine of 78) for polyps 1-5 mm, 52.9% (nine of 17) for polyps 6-9 mm, and 100% (three of three) for polyps over 10 mm. Results at colonoscopy were normal in 29 (42.6%) of 68 patients; at CT colonography, results were correctly identified as normal in 26 of these 29 patients. In one of these patients, a lesion larger than 10 mm was detected at CT colonography. The per-patient specificity of CT was 89.7% (26 of 29; 95% CI: 72.7%, 97.8%). The mean time for CT image interpretation was 9 minutes. CONCLUSION: In patients at average risk for colorectal cancer, CT colonography is a sensitive and specific screening test for detecting polyps 10 mm or larger; the sensitivity for detecting smaller polyps is decreased. Examination findings can be interpreted in a clinically feasible amount of time.