MR Findings of Spinal Cord in Decompression Sickness

PURPOSE: To determine the MR imaging findings of spinal cord decompression sickness. MATERIALS AND METHODS: We retrospectively analysed the spinal MR images of eight patients (M : 6, F : 2) with decompression sickness affecting the cervical spine (n=1) or thoracic spine (n=7). The observed extent, location, continuity, signal intensity and contrast enhancement pattern of spinal cord lesions were analysed. RESULTS: The chief MR finding was continuous (n=2) or non-continuous (n=3) high signal intensity on T2-weighted images in the posterior paramedian spinal cord. In three cases, additional T2 signal abnormality in the ventral horn of the gray matter was observed. There was no signal intensity abnormality on T1- weighted images or abnormal enhancement on post-Gadolinium T1-weighted images. In one case, cord swelling in addition to T2 signal abnormality was observed. CONCLUSION: MR imaging is useful for evaluating spinal cord lesions in patients with decompression sickness.

A Pitfall in the Diagnosis of Bilateral Choanal Atresia: A Case Report

Choanal atresia is a rare congenital anomaly involving unilateral or bilateral posterior nasal choanal obstruction. Multiple associated anomalies have been described. We describe the case of a 1-month-old boy with bilateral choanal atresia, misdiagnosed after CT as a midline meningocele because the floor of the midline anterior cranial fossa was not ossified and secretion had accumulated in the obstructed posterior nasal choana.

Interdural Cyst of the Thoracolumbar Region

Spinal interdural cyst is an extremely rare lesion, the wall of which consists of a dura-like layer without arachnoid. This report describes two cases in which patients with interdural cysts of the thoracolumbar spine presented with atypical neurologic signs and symptoms, including lower back pain and radiating pian in both lower extremities. Plain radiographs, CT myelograms and magnetic resonance images were obtained, but the cysts could not be differentiated from extradural arachnoid cyst. Surgical intervention revealed a dura-like layer of cyst wall, and within the cyst, a fluid resembling cerebrospinal fluid was present. In one case, microscopic examination showed that fragments of connective tissue without an arachnoid lining formed a thin fibrous cystic wall, a finding consistent with meningeal cyst.

MR Imaging with FLAIR Pulse Sequence in Various Cerebral Lesions: Comparison with T2-Weighted Imaging

PURPOSE: To evaluate the utility of fluid-attenuated inversion recovery(FLAIR) sequence by comparing thesignal intensities in various cerebral lesions with those on T2-weighted MR imaging. MATERIALS & METHODS: In 41patients who showed different signal intensities between T2-weighted images and FLAIR sequences, we reviewed theVirchow-Robin space(VRS), acute or chronic infarctions including lacunar cavities, and postoperativeencephalomalacia. In all patients, the location, shape and size of abnormal signal intensities were evaluated. RESULTS: The hyperintensities of VRS and lacunar infarctions on T2-weighted imaging appeared as hypointensitieson FLAIR imaging. The hyperintense rims or crescents around lacunar cavities were only detected on FLAIR imaging.The extent of acute and chronic infarctions with homogenous hyperintensities seen on T2-weighted images was welldelineated on FLAIR imaging. Postoperative encephalomalacia and adjacent lesions showed low and high signalintensities, respectively, on FLAIR imaging, though they were hyperintense on T2-weighted images. CONCLUSION: ForVRS, infarction and encephalomalacia, FLAIR provides images that are superior to T2-weighted images, and may thusbe useful as an additional MR sequence in various cerebral lesions.