Torcular Dural Sinus Malformation: Fetal and Postnatal Imaging Findings and Their Associations With Clinical Outcomes.

BACKGROUND: Torcular dural sinus malformations (tDSMs) are rare vascular malformations that present in fetuses and infants. Existing data on prognostic imaging features, as well as the associated morbidity and mortality, are limited and variable. We therefore reviewed cases of tDSMs diagnosed on fetal magnetic resonance imaging (MRI) at our referral center to identify pre- and postnatal MRI imaging features associated with long-term outcomes. METHODS: We searched our imaging database for fetal and postnatal MRI reports of tDSM cases. The electronic medical record was then reviewed for pre- and postnatal clinical data, including follow-up imaging. Neurological outcomes were characterized using the previously reported scale based on the Bicêtre Score. Imaging features association with outcome scores were compared using the Fisher exact test. RESULTS: Sixteen cases of tDMS diagnosed by fetal MRI with postnatal clinical follow-up were identified, 11 of whom underwent postnatal MRI. The majority of cases of tDSM (73%) decreased in size or resolved on postnatal follow-up study without treatment. Restricted diffusion and parenchymal hemorrhage on fetal MRI were the only imaging features identified significantly associated with unfavorable neurological outcome or death, present in two patients with poor outcomes (two of two) and only one with a normal outcome (one of 14) (P = 0.025). CONCLUSIONS: Findings of tDSM on fetal MRI most often regress and/or resolve with normal or mild neurological outcomes, with the most significant predictor of poor outcome being the presence of parenchymal injury on fetal MRI. In addition, a subset will present with venolymphatic malformations.

Paraspinal Edema Is the Most Sensitive Feature of Lumbar Spinal Epidural Abscess on Unenhanced MRI.

OBJECTIVE: Spinal epidural abscess (SEA) is a serious infection requiring prompt treatment and potential neurosurgical intervention. Although contrast-enhanced spine MRI is the mainstay for diagnosis of SEA, unenhanced MRI is typically performed for patients with nonspecific symptoms or insufficient clinical information. We evaluated the sensitivity and specificity of imaging features suggestive of SEA at unenhanced spine MRI. MATERIALS AND METHODS: We searched our database for contrast-enhanced lumbar spine MRI examinations from January 1, 2000, through August 1, 2014, with "epidural abscess" in the report. We included 68 patients older than 18 years with an enhancing epidural collection at MRI and surgical (60%), microbiologic (15%), or clinical (25%) confirmation of SEA. Sixty-eight age- and sex-matched control subjects without SEA were also selected. Three readers scored unenhanced MR images on the degree of psoas and paraspinal muscle edema, extent of bone marrow edema, and abnormal disk signal. RESULTS: Paraspinal edema was highly sensitive (97%) for SEA, with lower sensitivities for psoas (54%), bone marrow (65%), and disk edema (66%). Each of these markers was highly significant in univariate analysis (p < 0.001). A multivariate logistic regression model adjusting for age and sex found that paraspinal (p < 0.001) and bone marrow edema (p = 0.006) were significant independent predictors of SEA (odds ratio, 58; p < 0.001), with a trend toward significance for psoas edema and abnormal disk signal. Psoas muscle edema was the most specific (96%) finding for the presence of SEA. CONCLUSION: Paraspinal edema is highly sensitive for SEA. Familiarity with the findings for SEA at unenhanced MRI could help expedite further definitive evaluation when contrast agent is not administered.

The LxCxE pRb interaction domain of cyclin D1 is dispensable for murine development.

Cyclin D1 is a multifunctional, tumor-associated protein that interacts with pRb via a conserved LxCxE motif, activates a kinase partner, directs the phosphorylation of pRb, activates cyclin E-cyclin-dependent kinase 2 (cdk2) by titrating Cip/Kip cdk inhibitors, and modulates the activity of a variety of transcription factors. It is thought that some of the proproliferative function of cyclin D1 is exerted by LxCxE-dependent binding to the pRb pocket domain, which might interfere with the ability of pRb to repress transcription by recruiting cellular chromatin remodeling proteins to E2F-dependent promoters. To test the importance of the LxCxE domain in vivo, we have generated a "knock-in" mouse by replacing the wild-type cyclin D1 gene with a mutant allele precisely lacking the nucleotides encoding the LxCxE domain. Analysis of this mouse has shown that the LxCxE protein is biochemically similar to wild-type cyclin D1 in all tested respects. Moreover, we were unable to detect abnormalities in growth, retinal development, mammary gland development, or tumorigenesis, all of which are affected by deleting cyclin D1. Although we cannot exclude the presence of subtle defects, these results suggest that the LxCxE domain of cyclin D1 is not necessary for function despite the absolute conservation of this motif in the D-type cyclins from plants and vertebrates.