Taher El Gammal

Cerebral infarction in sickle cell anemia Mechanism based on CT and MRI

We studied 25 patients with sickle cell anemia and cerebral infarction. We classified lesions as to probable mechanism (large versus small vessel disease) based on the CT/MRI appearance of established infarction. Most patients had CT/ MRI patterns of major cerebral vessel occlusion (41%) or borderzone (distal insufficiency) infarcts (31%) best explained by large cerebral vessel vasculopathy. Seven of 25 (28%) had either isolated subcortical (12%) or small cortical branch occlusion (16%) consistent with other mechanisms such as small vessel occlusion or embolism. These results suggest that most clinically recognized cerebral infarctions in sickle cell anemia are caused by large vessel disease, but this mechanism may not account for symptoms of cerebral ischemia in all cases.

Cranial arteritis associated with herpes zoster. Case report with angiographic findings.

Abstract Angiographic findings of unilateral angiitis in a case of herpes zoster ophthalmicus with contralateral hemiplegia are described. Herpes zoster is often associated with major CNS involvement and a vascular etiology was previously postulated. Recent pathological reports suggest that cerebral angiitis secondary to herpes virus infection may be more common than heretofore realized. Our findings suggest a means by which suspected cases can be more fully evaluated.

Evaluation of brain and epidural abscesses by computed tomography.

Most brain abscesses have a characteristic but nonspecific appearance on computed tomography (CT), consisting of a ring configuration of the abscess capsule which shows marked enhancement after injection of contrast material. CT scanning is invaluable in both the initial investigation of a brain abscess and assessment of its response to therapy. The CT scan showed a peripheral low-density crescent in one case of epidural abscess.

The value, limitations, and applications of nuclear dacryocystography

Nuclear dacryocystography is simple, relatively harmless method of evaluating patients suspected of having abnormalities of the nasolacrimal drainage system. A group of normal saline containing approximately 100 muCi of 99mTc-pertechnetate is placed on the conjunctiva near the lateral canthus, and serial scintigrams are obtained as the pertechnetate flows along the tear strips, through the nasolacrimal drainage system, into the nasal fossa. By using a pinhole collimator with a very small aperture (1mm), the canaliculi, the nasolacrimal sac, and the nasolacrimal duct are readily visualized. When flow is impaired, the site of obstruction can often be identified. Contrast dacryocystography provides similar information but requires the injection of contrast material directly into a canaliculus. Nuclear dacryocystography provides good functional assessment of nasolacrimal drainage but has serious shortcomings in defining pathologic anatomy. Contrast dacryocystography outlines the anatomy well but often misses minor obstructions. The two studies are complementary and together provide an effective means of evaluating the nasolacrimal drainage system.

Giant posterior inferior cerebellar artery aneurysm with dysphagia

Presented is a case of giant aneurysm of the posterior inferior cerebellar artery with the unusual clinical presentation of dysphagia to the point of inability to swallow even oral secretions, resulting in severe malnutrition. A computed tomography scan with contrast-medium enhancement appeared normal. The correct diagnosis was suspected from the results of metrizamide myelocisternography and was confirmed at angiography. The patient underwent ligation of the feeding right vertebral artery with subsequent improvement in her dysphagia and resolution of her other neurological deficits. Discussion of the incidence, diagnosis, and treatment of this uncommon lesion is presented.

Ventriculoperitoneal shunt metastasis of a pineal germinoma

Metastasis of pineal germinoma to the peritoneal cavity via the patients ventriculoperitoneal shunt represents an unusual complication of this rare tumor. We report such a case with autopsy correlation of the abdominal CT findings. CT accurately delineated the extent of the metastatic mass and revealed associated complications including biliary tract obstruction, thrombosis of the inferior vena cava and a small amount of ascitic fluid. Since this tumor is very sensitive to radiotherapy and chemotherapy, the need for early detection of such metastasis is apparent. Possible implications with respect to the management of these patients are considered.

Irreversible neurologic complications of metrizamide myelography

Metrizamide, a major contrast agent for myelographic procedures, has rarely been reported to cause irreversible neurologic complications. The major transient neurologic alterations include neuropsychological reactions, generalized tonic-clonic seizures, and headaches. Two cases of irreversible spinal neurologic deficits resulting from metrizamide myelography are reported, and the factors that may increase the risks of complications in metrizamide myelographic studies are discussed, including preexisting dehydration, patient positioning, and the concentration of contrast agent.

Cerebellar atrophy in epilepsy and headache Lack of relationship to phenytoin

CT scans of 70 patients with seizures and 48 patients with headaches were studied. Using accepted CT criteria for the diagnosis of cerebellar atrophy, the films were analyzed in a blind, unbiased fashion to evaluate possible relationship between cerebellar atrophy and phenytoin use or epilepsy itself. We found no evidence that either phenytoin or epilepsy caused cerebellar atrophy.

High resolution computed tomography in neonatal nasopharyngeal teratoma

A case of neonatal teratoma of the nasopharynx associated with polyhydramnios and respiratory distress is presented. Surgical excision was carried out after preoperative evaluation with high resolution CT. Computed tomography is valuable in distinguishing a teratomatous tumor and in searching for intracranial extension and malignant characteristics.