MR Imaging Knee Synovitis and Synovial Pathology.

Knee synovitis is a common, but nonspecific finding on MR imaging in patients with knee pain, with causes ranging from post-traumatic and osteoarthritis to inflammatory and infectious causes. Synovial thickening, joint effusion, and synovial enhancement are present across the spectrum of etiologies and do not allow differentiation between them in most instances. This article reviews synovial physiology and MR imaging of the normal synovium and synovitis, with discussion of specific pathologies and limited signs that suggest one diagnosis over another. Intravenous contrast is helpful across the spectrum of pathologies to distinguish joint fluid from synovial proliferation.

Unruptured Arteriovenous Malformations in the Multidetector Computed Tomography Era: Frequency of Detection and Predictable Failures.

OBJECTIVES: While hemorrhage arising from ruptured arteriovenous malformations (AVMs) is usually evident on multidetector non-contrast computed tomography (NCCT), unruptured AVMs can be below the limits of detection. We performed a retrospective review of NCCT of patients with a proven diagnosis of unruptured AVM to determine if advances in CT technology have made them more apparent and what features predict their detection. MATERIAL AND METHODS: Twenty-five NCCTs met inclusion criteria of having angiography or MR proven AVM without hemorrhage, prior surgery, or other CNS disease. Demographic variables, clinical symptoms at presentation, abnormal CT imaging findings, attenuation of the superior sagittal sinus (SSS), and Spetzler-Martin grade of each AVM were recorded. We examined the relationship between AVM detection and SSS attenuation through Kruskal-Wallis test. Exploratory serial logistic principal components analysis was performed including demographics, symptoms, and CT features in the multivariate model. RESULTS: About 80% of the NCCTs showed an abnormality while 20% were normal. All those with an identifiable abnormality showed hyperdensity (80%). Logistic regression models indicate that clustered associations between several CT features, primarily calcifications, hyperdensity, and vascular prominence significantly predicted Spetzler-Martin grade (likelihood ratio 7.7, P = 0.006). SSS attenuation was significantly lower in subjects with occult AVMs when compared to those with CT abnormalities (median 47 vs. 55 HU, P < 0.04). CONCLUSION: Abnormal hyperdensity was evident in all detectable cases (80%) and multiple CT features were predictive of a higher Spetzler-Martin AVM grade. Moreover, SSS attenuation less than 50 HU was significantly correlated with a false-negative NCCT.

Detecting Intestinal Malrotation on Hepatobiliary Scintigraphy: Making a Case for a Better Standardized Reporting Template.

Intestinal malrotation displays classic pattern of the small bowel activity on hepatobiliary scintigraphy that could lead to the diagnosis, but only if an interpreting physician looks for it. Presented are 2 cases, one demonstrates diagnostic findings during the first 60-minute phase, whereas the other reveals the diagnosis only on the later sincalide stimulation phase. The currently recommended structured reporting for hepatobiliary scintigraphy does not include examination of bowel activity pattern, which could result in a missed diagnosis. Including interrogation of the small bowel pattern into the structured reporting checklist would ensure consistent detection of this rare but most consequential diagnosis.