Hani A. Haykal

Statistical assessment of perceptual CT scan ratings in patients with alzheimer type dementia

Three neuroradiologists perceptually evaluated CT of 24 patients with Alzheimer type dementia and 22 normal control subjects and made a dichotomous judgment for each case (i.e., normal control or Alzheimer type dementia). The mean percentage of patients correctly classified was 83.3%. The neuroradiologists also completed perceptual ratings on each scan. Thirteen regions were rated for atrophy on a scale of 0-4. Discriminant function analyses of several sets of perceptual atrophy ratings (optimized on an exploratory set and evaluated on a test set) showed that the perceptual ratings of temporal lobe regions produced an average accuracy of 88.57%. In contrast, only 74.26% of the cases were correctly classified when the discriminant functions were based on perceptual ratings of midventricular and supraventricular areas. Linear measures of atrophy correctly classified only 65.20% of the subjects. The results suggest that atrophy ratings of brain regions that show the characteristic macroscopic neuropathological changes of Alzheimer disease may be used by neuroradiologists to reach more accurate diagnostic decisions.

Synovial cysts of the lumbar spine: CT evaluation

Seven cases of surgically proven intraspinal synovial cysts are reported. Computed tomographic (CT) scans demonstrated a series of low-density masses adjacent to the facet joints; in three cases, a dense rim indicated a calcified wall on the cyst; in one, the wall was partially calcified; and in three the mass appeared to be filled with gas. In all of these cases, there was severe degenerative facet disease at the same level as the synovial cyst. In six patients, the cysts were unilateral, while one was bilateral; seven cysts were located at the level of L4-L5, and one at L3-L4. We conclude from this study that the intraspinal synovial cyst can be identified reliably by the CT scan.

CT diagnosis of delayed cerebral air embolism following intraaortic balloon pump catheter insertion

Air embolism to the brain occurred several days after insertion of an intraaortic balloon pump. CT demonstrated diffuse hemispheric edema along with two small collections of air in the cerebral hemispheres. Early diagnosis of air embolism to the brain allows early institution of proper therapy in this life-threatening condition.

Chloroma of cerebellum, tentorium and occipital bone in acute myelogenous leukemia.

A 60-year-old female with a ten-month history of acute myelogenous leukemia, now in hematologic remission, presented with severe dizziness, unsteady gait, nausea and vomiting. She had recently received two courses of chemotherapy, including daunorubicin and ARA-C. She was admitted to Brigham and Womens Hospital. Cranial CT (Figs. 1 and 2) showed a high-density mass in the left cerebellar hemisphere, with central lucency and dense peripheral enhancement. There was osteolytic bone destruction of the inner table of occipital bone on both sides, confirmed on plain films and very dense tentorial enhancement as well as obstructive hydrocephalus. A left vertebral angiogram demonstrated a relatively avascular mass in the left cerebellar hemisphere without venous occlusion. Biopsies of the left cerebellar mass and left occipital bone proved to be chloroma. A follow-up cranial CT two months after the completion of radiation therapy (900 rad delivered to the whole brain and 2600 rad to the posterior fossa) showed complete resolution of the posterior fossa lesions.

Balloon Occlusion of a Recurrent Carotid-Cavernous Fistula Previously Treated by Carotid Ligations

A carotid-cavernous fistula recurred 16 years after a Hamby procedure. The recurrence was manifested by subarachnoid hemorrhage originating from dilated draining pial veins. The fistula was closed with a balloon catheter introduced through a patent remnant of the cervical carotid artery. Patients who have previously undergone Hamby trapping and embolization should be reassessed for an occult fistula that could predispose them to intracranial bleeding.

Thoracic spinal metastasis from unexpected cerebellar medulloblastoma: the value of MRI.

A 28-year-old male was found on CT metrizamide myelography to have an intradural extramedullary tumor at the T8-T9 level. This was seen to compress the spinal cord, and on surgery it was proven to be medulloblastoma. Cranial CT scans disclosed only mild hydrocephalus and minimal anterior displacement of the inferior fourth ventricle on the right. However, magnetic resonance imaging (MRI) which was performed after the spinal surgery demonstrated an inferior cerebellar vermian tumor.

Computed tomography of aneurysmal bone cyst of the L1 vertebral body.

A 31-year-old woman with an aneurysmal bone cyst of the L1 vertebral body proved by biopsy and studied by plain lumbar spine roentgenography, radionuclide studies, myelography, and CT is presented. The unusual location of involvement of the vertebral body alone and the difficulty in differential diagnosis between aneurysmal bone cyst and benign giant cell tumor are discussed.