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BACKGROUND AND PURPOSE: While enhanced T1WI is considered the “gold standard” for detection of internal auditory canal pathology, unenhanced fluid-sensitive sequences have shown high sensitivity for lesion identification. Our purpose was to evaluate the diagnostic accuracy of an unenhanced MR imaging protocol using axial CISS and coronal T2WI for detection of small (10 mm or less) internal auditory canal lesions. MATERIALS AND METHODS: Twenty-three patients with small internal auditory canal lesions and 13 patients without lesions who had undergone MR imaging using the screening protocol and confirmatory gadolinium-enhanced thin section T1WI were identified. Two blinded neuroradiologists retrospectively evaluated all examinations using 1) only axial CISS, 2) only coronal T2WI, and 3) axial and coronal sequences together. Accuracy, specificity, sensitivity, and interobserver agreement were assessed. RESULTS: Median maximum lesion dimension was 4 mm (range, 2–10 mm). Accuracy, specificity, and sensitivity for axial CISS alone were 0.94, 0.96, and 0.91 for observer 1 and 0.94, 0.92, and 1.00 for observer 2. The data for the coronal T2WI sequence only were 0.94, 0.96, and 0.91 for observer 1, and 0.99, 1.00, and 0.96 for observer 2. Using axial and coronal sequences, the data were 0.97, 0.96, and 1.00 for observer 1, and 0.99, 0.98, and 1.00 for observer 2. κ coefficients were 0.84 for the axial sequence only, 0.90 for coronal only, and 0.91 for axial and coronal both. CONCLUSIONS: Screening noncontrast MR imaging using a combination of axial CISS and coronal T2WI sequences can detect small internal auditory canal lesions with 100% sensitivity and excellent interobserver agreement.

BACKGROUND AND PURPOSE: The craniopharyngeal canal is a rare, well-corticated defect through the midline of the sphenoid bone from the sellar floor to the anterosuperior nasopharyngeal roof. We reviewed a series of craniopharyngeal canals to determine a system of classification that might better our understanding of this entity, highlight the range of associated pathologic conditions, and optimize patient treatment. MATERIALS AND METHODS: Available MR imaging, CT, and clinical data (from 1989–2013) of 29 patients (10 female, 15 male, 4 unknown; median age, 4 years; age range, 1 day–65 years) with craniopharyngeal canals were retrospectively examined. Qualitative assessment included orthotopic or ectopic adenohypophysis and the presence of a tumor and/or cephalocele. The midpoint anteroposterior diameter was measured. Clinical and imaging data were evaluated for pituitary dysfunction and accompanying anomalies. RESULTS: Craniopharyngeal canals were qualitatively separated into 3 types: incidental canals (type 1); canals with ectopic adenohypophysis (type 2); and canals containing cephaloceles (type 3A), tumors (type 3B), or both (type 3C), including pituitary adenoma, craniopharyngioma, dermoid, teratoma, and glioma. Quantitative evaluation showed a significant difference (P < .0001) in the anteroposterior diameters of type 1 canals (median, 0.8; range, 0.7–1.1 mm), type 2 canals (median, 3.9, range, 3.5–4.4 mm), and type 3 canals (median, 9.0; range, 5.9–31.0 mm) imparting small, medium, and large descriptors. Canals with cephaloceles all contained an ectopic adenohypophysis. The craniopharyngeal canals were associated with pituitary dysfunction (6/29) and congenital anomalies (8/29). CONCLUSIONS: Accurate diagnosis and classification of craniopharyngeal canals are valuable to characterize lesions requiring surgery, identify patients with potential pituitary dysfunction, and avoid iatrogenic hypopituitarism or CSF leak during surgical resection of nasopharyngeal masses.

To further characterize the anatomy of the fifth lumbar to first sacral (L5-S1) disc space and to provide anatomic landmarks that can be used to predict the locations of the disc, sacral promontory, and surrounding structures during sacrocolpopexy.The lumbosacral anatomy was examined in 25 female cadavers and 100 computed tomography (CT) studies. Measurements were obtained using the midpoint of the sacral promontory as a reference. Data were analyzed using Pearson χ, unpaired Student's t test, and analysis of covariance.The average height of the L5-S1 disc was 1.8±0.3 cm (range 1.3-2.8 cm) in cadavers and 1.4±0.4 cm (0.3-2.3) on CT (P.001). The average angle of descent between the anterior surfaces of L5 and S1 was 60.5±9 degrees (39.5-80.5 degrees) in cadavers and 65.3±8 degrees (42.6-88.6 degrees) on CT (P=.016). The average shortest distance between the S1 foramina was 3.4±0.4 cm in cadavers and 3.0±0.4 cm on CT (P.001). The average height of the first sacral vertebra (S1) was 3.0±0.2 cm in cadavers and 3.0±0.3 on CT (P=.269).In the supine position, the most prominent structure in the presacral space is the L5-S1 disc, which extends approximately 1.5 cm cephalad to the "true" sacral promontory. During sacrocolpopexy, awareness of a 60-degree average drop between the anterior surfaces of L5 and S1 vertebra should assist with intraoperative localization of the sacral promontory and avoidance of the L5-S1 disc. The first sacral nerve can be expected approximately 3 cm from the upper surface of the sacrum and 1.5 cm from the midline.II.

The objective of the study was to further characterize the vascular and ureteral anatomy relative to the midsacral promontory, a landmark often used during sacrocolpopexy, and suggest strategies to avoid complications.Distances between the right ureter, aortic bifurcation, and iliac vessels to the midsacral promontory were examined in 25 unembalmed female cadavers and 100 computed tomography (CT) studies. Data were analyzed using Pearson χ(2), unpaired Student t test, and analysis of covariance.The average distance between the midsacral promontory and right ureter was 2.7 cm (range, 1.6-3.8 cm) in cadavers and 2.9 cm (range, 1.7-5.0 cm) on CT (P = .209). The closest cephalad vessel to the promontory was the left common iliac vein, the average distance being 2.7 cm (range, 0.95-4.75 cm) in cadavers and 3.0 cm (range, 1.0-6.1 cm) on CT (P = .289). The closest vessel to the right of the promontory was the internal iliac artery, with the average distance of 2.5 cm (range, 1.4-3.9 cm) in cadavers and 2.2 cm (range, 1.2-3.9 cm) on CT (P = .015). The average distance from the promontory to the aortic bifurcation was 5.3 cm (range, 2.8-9.7 cm) in cadavers and 6.6 cm (range, 3.1-10.1 cm) on CT (P.001). The average distance from the aortic bifurcation to the inferior margin of the left common iliac vein was 2.3 cm (range, 1.2-3.9 cm) in cadavers and 3.5 cm (range, 1.7-5.6 cm) on CT (P.001).The right ureter, right common iliac artery, and left common iliac vein are found within 3 cm from the midsacral promontory. A thorough understanding of the extensive variability in vascular and ureteral anatomy relative to the midsacral promontory should help avoid serious intraoperative complications during sacrocolpopexy.