December 2000: 6 month old boy with 2 week history of progressive lethargy.

This 6-month-old Caucasian boy presented with a 10-day history of lethargy, obtundation, inability to hold his head up and mild torticollis. MRI and CT scans showed a large solid and cystic mass involving the right temporal, parietal and occipital lobes, pineal, superior pons, mesencephalon and posterior right thalamus. He underwent craniotomy initially for a partial tumor resection with an intraoperative diagnosis of desmoplastic astrocytoma. With immunohistochemistry and special stains the diagnosis of desmoplastic infantile ganglioglioma (DIG) was made. A near total resection was performed a week after initial resection.The patient then was treated with chemotherapy. Two months later an MRI showed tumor growth. Following additional aggressive chemotherapy, an MRI at 5 months post-resection indicated further tumor progression. This case illustrates that some DIGs may behave more aggressively than typical WHO grade I lesions.

Gadolinium-enhanced magnetic resonance imaging in Bell's palsy.

Inflammation of the facial nerve in Bell's palsy can be demonstrated on gadolinium-enhanced magnetic resonance imaging. We have studied a series of 17 Bell's palsy patients with gadolinium-enhanced magnetic resonance imaging, and the purpose of this paper is to report our findings and discuss their significance. Most acute Bell's palsy cases demonstrate facial nerve enhancement, usually in the distal internal auditory canal and labyrinthine/geniculate segments. Other segments demonstrate enhancement less often. Gadolinium enhancement occurs regardless of the severity of the paralysis and can persist after clinical improvement of the paralysis. The findings of this study corroborate other evidence that the segments of the facial nerve most often involved in Bell's palsy are the only segments that are most often enhanced with gadolinium-enhanced magnetic resonance imaging. The role of gadolinium-enhanced magnetic resonance imaging in the management of Bell's palsy patients is discussed.

Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance.

Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.

Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance.

Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.

Falx ossification--MR visualization.

While falx calcification is rarely demonstrated using magnetic resonance, falx ossification, when seen, is characteristic. On magnetic resonance images, falx ossification exhibits a typical appearance consisting of a central marrow-containing portion with signal intensity similar to fat, surrounded by low signal intensity representing cortical bone. Falx ossification was seen in 0.7% of patients and should not be confused with a falx lipoma, a rare congenital entity.

Imaging of cranial chordomas.

The clinical, pathologic, and imaging characteristics of clival chordomas in 14 patients who underwent magnetic resonance examinations were evaluated. Magnetic resonance imaging (MRI) was compared with skull series, tomography, computed tomography (CT), and magnification angiography in the diagnosis of clival chordomas. Although all examinations were highly sensitive for the detection of clival chordomas, MRI was the best single study because of its ability to image in orthogonal planes, its excellent soft-tissue contrast, and its demonstration of the relationship between the neoplasm and regional vital structures, particularly the brainstem, cavernous sinus, cranial nerves, and neighboring vessels. The deficiencies of MRI are poor visualization of tumoral calcification and osseous destruction--findings that are better identified on CT. In all 14 cases, MRI revealed the neoplasms to be black on inversion-recovery, gray on partial-saturation, and white on T2-weighted pulse sequences. Three chordomas had a speckled signal void pattern, typical of tumor calcification.

Glomus tympanicum chemodectomas: radiographic and clinical characteristics.

Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.

Primary spinal melanoma.

The records of five patients with primary melanoma of the spinal cord were reviewed. The tumor most frequently presented as an intramedullary middle or lower thoracic cord lesion. The average duration of symptoms before pathological diagnosis was 29 months, and the average survival after laminectomy and radiation therapy was 6 years 7 months. The findings in this series, when compared with those in the literature, suggest that primary spinal melanoma is a more indolent malignancy than previously reported or than melanoma metastatic to the central nervous system.

Computer-assisted scheduling of radiology resident call.

The difficulties inherent in assigning an entire residency group fair and equivalent daily call prompted the development of a computerized scheduling program at The University of Texas at Houston. Written in COBOL, the program is run on a CDC mainframe computer. Logic parameters restrict the number and frequency of calls per month, and each resident is coded for five available call types at two university hospitals. The foundation of the program's operation is an arbitrary point scale applied to each call type determined by its difficulty and time commitment. Residents' point totals each month are roughly balanced within a prescribed range, with call exchanges made by the computer if necessary. The computer-generated schedules are flexible and equitable, require little manual correction, and save time for the chief resident and the residency secretary.

Complications of colonic interposition.

The roentgenographic and surgical experience with 44 patients treated with colon interpositions was examined. Forty-two of these patients had carcinoma of the esophagus. Staged therapy consisted of mediastinal irradiation, colonic interposition, and total esophagectomy. The more common complications related to luminal patency and conduit integrity. A total of 29.5% developed anastomotic narrowing due to postoperative edema. Anastomotic leaks arose only at the proximal anastomosis and had an incidence rate of 31.8%. Thirty-four percent had fistulous tracts originating in the reconstructed upper gastrointestinal tract. In eighty percent of the patients with leaks or fistulae, their defects healed spontaneously or with simple drainage. Strictures were encountered in 59.1%, and there were 5 instances of colonic graft ischemia. The mortality directly related to surgery was 6.8%. Ischemia, particularly at the cervical anastomosis, is probably the most common cause of complications. Radiographic evaluation is recommended using a single contrast barium examination unless gross extravasation is expected.