Dieter R. Enzmann

The anatomy of the posterior communicating artery as a risk factor for ischemic cerebral infarction.

BACKGROUND After the occlusion of an internal carotid artery the principal source of collateral flow is through the arteries of the circle of Willis, but the size and patency of these arteries are quite variable. Study of the anatomy of the collateral pathways in patients with internal-carotid-artery occlusion with or without infarction in the watershed area of the deep white matter may identify patterns that afford protection from ischemic infarction. METHODS Using conventional magnetic resonance imaging and three-dimensional phase-contrast magnetic resonance angiography, we evaluated 29 consecutive patients (32 hemispheres at risk) with angiographically proved occlusion of the internal carotid artery. Four collateral pathways to the occluded vessel were evaluated: the proximal segment of the anterior cerebral artery, the posterior communicating artery, the ophthalmic artery, and leptomeningeal collateral vessels from the posterior cerebral artery. RESULTS Only features of the ipsilateral posterior communicating artery were related to the risk of watershed infarction. The presence of posterior communicating arteries measuring at least 1 mm in diameter was associated with the absence of watershed infarction (13 hemispheres, no infarcts; P < 0.001). Conversely, there were 4 watershed infarcts in the 6 hemispheres with posterior communicating arteries measuring less than 1 mm in diameter and 10 infarcts in the 13 hemispheres with no detectable flow in the ipsilateral posterior communicating artery. CONCLUSIONS A small (< 1 mm in diameter) or absent ipsilateral posterior communicating artery is a risk factor for ischemic cerebral infarction in patients with internal-carotid-artery occlusion.

Cranial computed tomography findings in anorexia nervosa.

Four patients with anorexia nervosa were studied by cranial computed tomography (CT). Three of the four demonstrated abnormal enlargement of cortical sulci and subarachnoid spaces as compared with an age-matched control group. The relationship of this finding to established neuropathological changes in anorexia nervosa is discussed.

Intravenous gammaglobulin therapy in recurrent acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disorder of the CNS that seems to be immune mediated. [1,2] It is usually preceded by a viral syndrome and presents with acute neurologic signs. [1] ADEM is usually monophasic, but recurrent episodes may occur. [3] When ADEM is recurrent, the distinction from MS becomes difficult. [2] Corticosteroids are commonly used in ADEM and are thought to shorten the duration of the neurologic symptoms. [4] We report on the use of intravenous gammaglobulin (IVIG) therapy for ADEM after failure of corticosteroids. An 8-year-old previously healthy boy developed headaches and fever 2 weeks before admission to Packard Childrens Hospital at Stanford. He was admitted to a community hospital. Vital signs were normal except for a temperature of 100.9 degrees F. There were no signs of meningeal irritation. LP showed 23 WBC/mm3 (34% polymorphonuclear cells, 45% lymphocytes, 21% monocytes), 0 RBC/mm3, with a protein of 23 mg/dL and a glucose of 63 mg/dL. MRI showed prominent leptomeningeal enhancement but no other lesions. He was diagnosed with viral meningitis and treated with IV acylovir for 9 days. Headaches worsened despite analgesics, and he was transferred to the Childrens Hospital. On examination, he was awake but in significant distress from a severe headache. His speech and comprehension were normal. Vital signs were normal except for a temperature of 100.7 degrees F. The general examination was unremarkable. There were several beats of ankle clonus, and the plantar responses were extensor bilaterally. The …

Experimental Brain Abscess Evolution: Computed Tomographic and Neuropathologic Correlation

Brain abscess evolution was studied in dogs by correlating the CT appearance with the neuropathologic findings. The abscess, produced by direct inoculation, progressed from an area of cerebritis to a well encapsulated abscess over 14 days. Ring enhancement was seen in the cerebritis stage prior to capsule formation. The ring reached its maximum size at this stage and correlated best with the area of cerebritis surrounding the developing necrotic center; the rim of this ring increased in thickness, resulting in progressive diminution of the central lucent area on scans delayed up to 60 min. The diameter of the ring decreased as cerebritis receded. Once the capsule had formed, the central lucent area was similar and no longer filled in on delayed scans.

Computed Tomography of Herpes Simplex Encephalitis

On the initial computed tomographic (CT) scan in 10 of 13 patients with herpes simplex encephalitis (HSE), the most characteristic finding was a unilateral, low-density lesion in the medial temporal lobe and/or insular cortex. This lesion was seen in all patients as the disease progressed. When associated with hemorrhage and streaked contrast enhancement this lesion added specificity to the CT scan, but this situation occurred in only 3 patients. Early in the course of HSE, focal CT findings localized the temporal lobe of greatest involvement in 12 patients; 1 had a normal initial CT scan.

Computed Tomography in Primary Reticulum Cell Sarcoma of the Brain

The CT findings in 16 patients with histologically proved primary central nervous system (CNS) reticulum cell sarcoma (RCS) showed this malignancy to have predilection for the basal ganglia and thalamus, the periventricular white matter, the corpus callosum, and the vermis cerebelli. In 43% of patients with untreated tumor it presented as multifocal lesions; in each of these patients the basal ganglia were involved in conjuction with another site. In the other 57% of patients with untreated tumor presenting as solitary lesions the basal ganglia, the corpus callosum, and the frontal lobe were sites of predilection. Such solitary lesions may be indistinguishable from other tumors. Contrast enhancement of RCS was characteristically homogeneous with rare lucency, even in very large lesions.

Diagnosis of Progressive Multifocal Leukoencephalopathy by Computed Tomography

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system which predominantly affects immunologically compromised hosts. The distinctive CT appearance in three documented cases includes low-density lesions of central and convolutional white matter with scalloped lateral borders. Lesions demonstrate no mass effect or contrast material enhancement. Findings are discussed with reference to other entities which may produce a similar CT appearance.

Computed tomography in leptomeningeal spread of tumor.

Computed tomography proved insensitive to leptomeningeal spread of hematologic malignancies including leukemia, lymphoma, and malignant histiocytosis. In only 3% of patients did it directly demonstrate leptomeningeal tumor. In comparison, the detection rate of leptomeningeal tumor secondary to carcinoma was 44% and for melanoma, 100%. Intracranial subarachnoid seeding from primary brain gliomas was detected in each instance. The simultaneous presence of parenchymal metastases with leptomeningeal carcinomatosis occurred in 18% of patients with nonhematologic malignancies. Computed tomography evidence of communicating hydrocephalus, previously thought to be a major factor in clinical symptomatology, occurred in only 11% of patients.

Computed Tomography in the Evaluation of Malignant Glioma Before and After Therapy

Sixty-three patients with malignant glioma undergoing chemotherapy and radiotherapy were evaluated with electroencephalography, 99mTc-DTPA imaging, and computed tomography (CT). Tumor size, central lucency, contrast enhancement, surrounding edema, and ventricular size were assessed. CT findings were found to be reliable and often predicted the clinical course. Tumor size, central lucency, and contrast enhancement increased in patients with clinical deterioration and decreased in those with improvement. The CT scan also provided additional information of value in adjunctive therapy, such as the presence of cysts or ventricular obstruction. In general, CT gave a more complete profile of tumor characteristics than other diagnostic modalities.

Positive rolandic sharp waves in the EEG of the premature infant

Ninety-seven EEGs from 30 premature infants found to have multifocal white matter necrosis on ultrasound (US) or autopsy were reviewed retrospectively. Twenty infants had intraparenchymal echodensities on US that developed into cystic lesions, a finding consistent with periventricular leukomalacia; 8 had intraparenchymal hemorrhages; and 2 had white matter necrosis at autopsy. Four of these infants had no intraventricular hemorrhage. Positive sharp waves in the central (rolandic) regions (PRS) were identified in 22 of these 30 infants (73%) and in 0 of 30 age-matched controls (p < 0.001). The presence of PRS on the EEG of the premature infant has a high correlation with white matter necrosis rather than with intraventricular hemorrhage. In all cases, this EEG pattern was present prior to the development of cavitations when echodensities were present on US.