Faculty Bibliography

PURPOSE: To identify objective imaging characteristics that are predictors of clinical deterioration after embolization of large intracranial tumors. MATERIALS AND METHODS: This HIPAA-compliant retrospective study was approved by the institutional review board, and informed consent was waived. The records of twelve patients with large intracranial tumors who underwent embolization were analyzed for imaging characteristics that would portend acute neurologic deterioration following embolization. The degree of midbrain compression was calculated by using the cisternal angle (the angle formed at the intersection of a line drawn along the midsagittal plane and a line drawn along the anterior aspect of the cerebral peduncle). Angiograms were evaluated for the degree of pre- and postembolization tumor blush. Neurologic status before and after embolization was evaluated. The Wilcoxon signed rank test was used to compare the cisternal angles ipsilateral and contralateral to the tumor. The cisternal angle was measured in 100 control subjects with no mass lesions to evaluate its normal distribution. RESULTS: Of the 12 patients, three experienced acute clinical deterioration after embolization. A feature common to these patients was substantial preprocedure midbrain compression, as indicated by a cisternal angle of less than 25 degrees , which was significantly less than the mean angle in the control group. Another consistent risk factor was a strong initial tumor blush pattern and a major blush reduction following embolization. CONCLUSION: Cisternal angle is an objective measure of midbrain compression. The presence of a cisternal angle less than 25 degrees (indicating severe midbrain compression), strong tumor blush, and major postprocedure blush reduction are predictors of clinical deterioration after embolization

Aplasia of the common crus is an uncommon congenital anomaly. We present the case of a patient with common crus aplasia and discuss the relevant embryology and the role of 3D CT in evaluation of this rare congenital anomaly

As has happened in all facets of neuroimaging, cross-sectional imaging has dramatically changed our approach and understanding of the anatomy and pathology of paranasal sinuses. We have moved away from plain film radiographs to modern high-resolution sinus computerized tomography (CT) and magnetic resonance imaging (MRI) that helps us better depict underlying normal anatomy and evaluate pathology. Recent advances in PET/CT imaging have introduced a physiologic aspect to anatomical imaging and holds promise to better stage and restage head and neck tumors. In this article, we describe the various imaging techniques, concerns, advantages and disadvantages of the individual techniques, and provide an overview of the various pathologies involving the paranasal sinuses

Imaging of the sella and surrounding structures has become essential in the evaluation of pituitary dysfunction and its causes. This article begins with a review of the normal anatomy of the sella and the imaging patterns in and about the normal pituitary gland. There exists considerable variability in the size and configuration of the normal gland in all age groups, and absolute determination of a 'large' or 'small' gland can prove difficult and problematic. Absence of the posterior bright-spot may indicate disruption of the normal stalk transport mechanisms. Microadenomas are well-resolved by magnetic resonance imaging as areas with reduced or delayed enhancement relative to the normal gland. Among hormonally active tumors, adrenocorticotropic hormone-releasing adenomas are most common in the first 11 years of life, while prolactinomas become more common into the teenage years. Macroadenomas tend to present clinically because of mass-effect on adjacent structures, such as the bitemporal hemianopsia seen with optic chiasm compression. Cystic lesions such as Rathke's cleft cysts are commonly seen in the gland, even in healthy children, and their presence need not correlate with any functional abnormality; however, such cysts can cause mass effect on the remaining gland, reflect hemorrhage into adenoma, or actually comprise the central portion of a more worrisome tumor such as craniopharyngioma. Solid tumors of the suprasellar region include optic pathway gliomas, hamartomas, and germinomas. Among inflammatory conditions, granulomatous diseases such as sarcoidosis have predilection for involvement of the suprasellar regions and can spread along perivascular spaces deep within the parenchyma. Because of the association of pituitary endocrinopathies with midline anomalies, one should pay careful attention to midline structures included on a sellar survey

Acute spontaneous subdural hematoma without the presence of a subarachnoid hemorrhage as a result of a ruptured aneurysm is rare. We present the case of a patient with an aneurysm of the intrasellar anterior communicating artery that caused hemorrhage solely into the subdural space. The hemorrhage then migrated down the spinal canal. Our case is unique because all these 3 rare processes occurred in a single patient. Identification of the cause of this type of hemorrhage in a timely fashion is crucial to the management of such a patient

In recent years, three-dimensional (3D) multiplanar reformatted images from conventional cross-sectional computed tomographic (CT) data have been increasingly used to better demonstrate the anatomy and pathologic conditions of various organ systems. Three-dimensional volume-rendered (VR) CT images can aid in understanding the temporal bone, a region of complex anatomy containing multiple small structures within a relatively compact area, which makes evaluation of this region difficult. These images can be rotated in space and dissected in any plane, allowing assessment of the morphologic features of individual structures, including the small ossicles of the middle ear and the intricate components of the inner ear. The use of submillimeter two-dimensional reconstruction from CT data in addition to 3D reformation allows depiction of microanatomic structures such as the osseous spiral lamina and hamulus. Furthermore, 3D VR CT images can be used to evaluate various conditions of the temporal bone, including congenital malformations, vascular anomalies, inflammatory or neoplastic conditions, and trauma. The additional information provided by 3D reformatted images allows a better understanding of temporal bone anatomy and improves the ability to evaluate related disease, thereby helping to optimize surgical planning

MR imaging features of mitochondrial encephalomyopathies, lactic acidosis, and stroke-like episodes, Kearns-Sayre/Pearson syndrome have been described in the literature. We describe extensive white matter changes with abnormal signal intensity lesions involving the deep gray nuclei and myelinated white matter tracts in an 18-year-old female with a large-scale 7.4 kb mitochondrial DNA deletion and a atypical presentation of Kearns-Sayre syndrome. Restricted diffusion due to status spongiosus at the involved sites is also discussed

MRI may be used for detecting cartilage invasion in patients with laryngeal carcinoma. However, the normal laryngeal ossification pattern has not been studied. Our purpose was to examine the normal age-related signal patterns in the cricoid, thyroid and arytenoid cartilages on T1-weighted images. Signal in the cartilages was assessed by two radiologists in a blinded fashion using three-point scales for intensity and symmetry. Statistical analysis consisted of logistic and monotonic regression. There was excellent interobserver agreement (>85%) for all categories. The cartilages predominantly ossify symmetrically and the extent of high signal from all three increases with age. The latter may help in detection of cartilage invasion by tumor in older patients. Normal symmetry may be helpful when comparing sides for tumor invasion

BACKGROUND AND PURPOSE: The insula is important for gustatory sensation, motor speech control, vestibular function, and sympathetic control of cardiovascular tone. The purpose of this study was to test two hypotheses: 1) gross anatomic study of the insula will disclose reproducible patterns of insular structure, and 2) analysis of MR appearance will enable physicians to recognize these patterns on imaging studies. METHODS: Gross insular anatomy was determined in 16 normal human cadaveric hemispheres. The 1.5-T MR images of 300 insulae were analyzed to determine the gyral and sulcal patterns displayed; their relationship to the Heschl gyrus, to the overlying opercula, and to the vertical planes perpendicular to the Talairach-Tournoux baseline at the anterior commissure (VAC) and posterior commissure (VPC); their continuity into the orbitofrontal cortex; and appropriate landmarks for the anterior border, apex, and posterior border of the insula. RESULTS: MR images displayed the central sulcus of the insula (97%); the anterior (99%), middle (78%), and posterior (98%) short insular gyri that converge to the apex (100%) anteriorly; and the anterior (99%) and posterior (58%) long insular gyri posteriorly. The middle short gyrus was often hypoplastic (33%). The anterior intersections of the internal and external capsules typically delimit the anterior insular border (87%). VAC intersects the anterior insula (99%), usually at the precentral sulcus. The Heschl gyrus circumscribes the posteroinferior insula (100%). VPC demarcates the posterior insular border (94%). CONCLUSION: The two hypotheses were proved correct. The insula shows reproducible patterns of gross anatomy that are demonstrable on routine clinical MR images obtained at 1.5 T