Chest computed tomography scores in patients with cystic fibrosis colonized with methicillin-resistant Staphylococcus aureus.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in cystic fibrosis (CF), with increasing incidence in recent years. We examined the association between bacterial colonization in the sputum (MRSA with or without pseudomonas (PA)) and computed tomography (CT) scores in CF patients. METHODS: MRSA patients were divided according to PA status based on at least three consecutive sputum cultures; controls were patients without MRSA (with or without PA), matched for gender and age at CT. Clinical data and CT scores were compared between groups. RESULTS: Of 33 patients with MRSA, 14 had no PA (MRSA + PA-) and 19 had also PA (MRSA + PA+). MRSA + PA- and MRSA + PA+ patients had CT scores similar to their controls PA+ (38.25 ± 20.18 vs. 32.22 ± 18.74, P = .4, and 41.88 ± 18.18 vs. 45.33 ± 11.5, P = .4, respectively). Although MRSA + PA- had worse CT scores than their matched PA- controls, their mean FEV1 values were similar. CONCLUSIONS: Colonization with MRSA in CF is associated with structural CT changes at least similar to those in PA. A cause and effect relationship cannot be established. The current findings call for a larger study assessing longitudinally the impact of MRSA acquisition and eradication protocols.

Main pancreatic duct intraductal papillary mucinous neoplasms: accuracy of MR imaging in differentiation between benign and malignant tumors compared with histopathologic analysis.

PURPOSE: To retrospectively determine the accuracy of magnetic resonance (MR) imaging combined with MR cholangiopancreatography (CP) in differentiating benign from malignant intraductal papillary mucinous neoplasms (IPMNs) involving the main pancreatic duct (MPD), with histopathologic analysis as the reference standard. MATERIALS AND METHODS: The informed consent requirement was waived for this institutional review board-approved study. A total of 51 patients with histopathologically proved IPMNs (MPD IPMN, n = 29; mixed type IPMN, n = 22), underwent MR imaging, MR CP, and surgery, with a mean interval of 2.6 months between MR examination and surgery. Qualitative image analysis included assessment of the site of MPD dilatation (head of the pancreas, body and/or tail of the pancreas, or diffuse), presence or absence of duct wall nodules, and contrast enhancement of the MPD walls. Quantitative image analysis included measurement of the maximum diameter of the MPD. A comparison of adenomas and borderline IPMNs with cancerous IPMNs was performed with the Student t test or the Mann-Whitney U test for continuous variables. RESULTS: At histopathologic analysis, 27 IPMNs were classified as carcinomas; 13, as borderline tumors; and 11, as adenomas. MPD wall nodules were observed in 16 carcinomas involving the MPD and one adenoma or borderline neoplasm (P < .00001). Duct wall enhancement was observed in 20 MPD or mixed type carcinomas and five adenomas or borderline neoplasms (P = .0001). The median maximal diameter of the MPD was 18 mm in malignant MPD or mixed type IPMNs and 11 mm in benign borderline IPMNs (P = .038). No significant difference in the overall 5-year survival rate of patients with MPD IPMNs and those with mixed type IPMNs was observed (P = .813). CONCLUSION: Duct wall nodules and enhancement of the MPD walls are signs of malignant MPD or mixed type IPMNs. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2531080604/-/DC1.

Diagnostic accuracy of MRCP in choledocholithiasis.

PURPOSE: To evaluate the accuracy of MRCP in diagnosing choledocholithiasis considering Endoscopic Retrograde Cholangiopancreatography (ERCP) as the gold standard. To compare the results achieved during the first two years of use (1999-2000) of Magnetic Resonance Cholangiopancreatography (MRCP) in patients with suspected choledocholithiasis with those achieved during the following two years (2001-2002) in order to establish the repeatability and objectivity of MRCP results. MATERIALS AND METHODS: One hundred and seventy consecutive patients underwent MRCP followed by ERCP within 72 h. In 22/170 (13%) patients ERCP was unsuccessful for different reasons. MRCP was performed using a 1.5 T magnet with both multi-slice HASTE sequences and thick-slice projection technique. Choledocholithiasis was diagnosed in the presence of signal void images in the dependent portion of the duct surrounded by hyperintense bile and detected at least in two projections. The MRCP results, read independently from the ERCP results, were compared in two different and subsequent periods. RESULTS: ERCP confirmed choledocholithiasis in 87 patients. In these cases the results of MRCP were the following: 78 true positives, 53 true negatives, 7 false positives, and 9 false negatives. The sensitivity, specificity and accuracy were 90%, 88% and 89% respectively. After the exclusion of stones with diameters smaller than 6 mm, the sensitivity, specificity and accuracy were 100%, 99% and 99%, respectively. MRCP accuracy was related to the size of the stones. There was no significant statistical difference between the results obtained in the first two-year period and those obtained in the second period. CONCLUSIONS: MRCP is sufficiently accurate to replace ERCP in patients with suspected choledocholithiasis. The results are related to the size of stones. The use of well-defined radiological signs allows good diagnostic accuracy independent of the learning curve.