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Biomedical subjects

D W Laster

Publications and source records attributed to D W Laster.

At least 37 records · Page 2Linked to original sources
PubMed1980

A comparison of brain imaging with gamma camera, single-photon emission computed tomography, and transmission computed tomography: concise communication.

We have evaluated the utility of a single-photon axial tomographic scanner (ECT) in brain imaging, using routine tracers in 238 patients. When compared with routine delayed gamma-camera images (DGCI), there was agreement in 191 negative studies and 39 positive studies. Four patients had positive DGCI and negative ECT studies, and four had positive ECT and negative DGCI. In the 102 patients in this series who also had transmission CT (TCT) studies, there were five who had positive emission studies and negative TCT, and 38 with an abnormal TCT and normal ECT. The ECT was occasionally helpful in distinguishing brain and skull metastases, in better portrayal of deep lesions, and in resolving equivocal DGCI findings. For the ECT to become clinically rewarding, however, we feel that it will need development of new tracers that will provide functional information in addition to that already attainable by routine gamma-camera images.

Adult↗
PubMed1979

Radiographic features of granulocytic sarcoma (chloroma).

The computed tomographic (CT) findings in two patients in whom intracranial granulocytic sarcomas preceded the onset of systemic myelogenous leukemia are presented. On CT, granulocytic sarcomas may be indistinguishable from meningiomas and difficult to differentiate from primary central nervous system malignant lymphoma and eosinophilic granuloma.

Adult↗
PubMed1979

Radionuclide sinography: diagnosis of lateral sinus thrombosis by dynamic and static brain imaging.

Four patients with lateral sinus thrombosis were studied by radionuclide (RN) dynamic studies and RN static brain scans. Findings included: (a) abrupt termination of RN activity in the midportion of a lateral sinus ("stump sign"); (b) nonvisualization on dynamic, increased visualization on static images ipsilateral to a prominent sinus groove on a plain skull radiograph; and (c) increased activity on static images with nonfilling on angiography. RN demonstration of the "stump sign" is pathognomonic of lateral sinus occlusion; the latter two patterns require radiographic demonstration of an ipsilateral sinus groove or angiography for significance.

Adult↗
PubMed1978

Clinical and computerized tomographic study of hypertensive intracerebral hemorrhage.

Historical, neurological, and computerized tomographic findings were correlated in 32 patients with hypertensive intracerebral hemorrhage. The mortality figures given in standard texts appear to be too high; the more acceptable figure would seem to be approximately 40%. Special attention was given to intraventricular rupture, which complicated 62% of the cases. Sudden onset of coma appears to correlate with the presence of intraventricular rupture. The "ring sign," if looked for, will be seen in most cases of resolving intracerebral hematoma.

Brain↗
PubMed1978

Computed tomography in late-infantile metachromatic leukodystrophy.

Computed tomography of 2 patients with late-infantile metachromatic leukodystrophy (MLD) demonstrated generalized white matter lucency and moderate ventricular enlargement. CAT scan findings in other white matter diseases likely to be confused clinically with MLD are sufficiently dissimilar to allow differentiation.

Brain↗
PubMed1978

Computerized cranial tomography of free intracranial fat in congenital tumors.

Three additional cases of free intracranial fat associated with congenital tumors are reported. The migration of fat with positional change is detailed. Free intraventricular fat may present without transcerebral rupture of the tumor. Our experience with these three patients, plus the two previously reported, suggest that two conditions must be present for oily material to enter the ventricular system through the outlets of the fourth ventricle: first, there must be a reversal of bulk flow of cerebrospinal fluid; second, the oily material must have a specific gravity less than that of cerebrospinal fluid. Also noted from our series is the absence of serious clinical sequelae associated with rupture or leakage of fatty tumors.

Adipose Tissue↗
PubMed1978

Computed cranial tomographic findings in cerebral sinovenous occlusion.

Eleven patients with angiographically and/or pathologically verified cerebral sinovenous occlusions not directly caused by trauma were studied by computed cranial tomography (CCT). Static radionuclide brain scans and dynamic radionuclide flow studies were also obtained in four patients; in two, findings diagnostic of lateral sinus thrombosis were noted. These comprised a "negative on dynamic, hot on static" image, as well as a "hot on static with nonfilling on angiography." Computed cranial tomography findings included visualization of the thrombosed vein ("cord sign") or sinus ("empty triangle" or "delta sign"), multiple focal bilateral parasagittal hemorrhages, intense tentorial enhancement, gyral enhancement indistinguishable from infarct, solitary intracerebral hematoma, small ventricles, and normal scan. Excluding the patients with underlying meningioma, all three of whom survived, seven of the remaining eight patients expired during the acute phase of their illness, an 88% mortality. This group includes one patient who had normal CCT findings, albeit without contrast enhancement, who was diagnosed as pseudotumor cerebri. The need for full neuroradiological evaluation, including angiography, is thus stressed if this highly fatal yet treatable condition is not to remain undiagnosed.

Adult↗
PubMed1978

Resolving intracerebral hematoma: alteration of the "ring sign" with steroids.

A ring of contrast enhancement is seen on CT scans of resolving intracerebral hematomas. This ring can be modified with steroid administration in the early stages; however, enhancement seen in the later stages is not affected. Evidence suggests that the early ring is due to blood-brain barrier breakdown, and the later enhancement is due to vascular granulation tissue. The following six stages of hematoma resorption were identified depending on the hematoma density, the presence or absence of a ring of enhancement, and the response of the ring to steroid administration: I = dense hematoma without enhancement; II = decreasing density, enhancement, modification of enhancement with steroid; III = isodense hematoma, enhancement, modification with steroid; IV = lucent hematoma, enhancement, modification with steroid; V = lucent hematoma, enhancement, no modification with steroid; and VI = healed, no enhancement.

Blood-Brain Barrier↗
PubMed1976

Jugular venography for evaluation of abnormalities of the skull base.

Jugular venography done to evaluate abnormalities at the base of the skull demonstrated three distinctly different patterns depending on whether there is occlusion, invasion, or growth with in the internal jugular vein. Improper technique results in a lack of intracranial dural sinus filling which may masquerade as venous occlusion. This problem is avoided by adequate neck compression along with proper volume and rate of delivery of contrast. Radiographically, an abnormal jugular vein at the base of the skull will show a concave defect in true occlusion, constriction or invasion of the vein by tumor, or tumor growth within the vein.

Aged↗
PubMed1976

The spectrum of growing skull fracture in children.

The genesis and complications of the growing skull fracture in children is discussed. Four patients are presented to illustrate the common and uncommon features of growing skull fractures. The need for complete radiological evaluation as well as the timing of follow-up examinations is stressed.

Brain Diseases↗
PubMedDate not supplied

MRI of corpus callosal syndromes.

Six patients, 6 to 13 years old, with corpus callosal abnormalities diagnosed by electroencephalography or CT were studied with a 0.15 T MR imager to determine the effectiveness of MRI in evaluating midline anomalies. Spin-echo images in the coronal, axial, and sagittal planes were obtained in two patients with Aicardi's syndrome and partial agenesis of the corpus callosum, in one patient with Dandy-Walker syndrome, and in two patients with septooptic dysplasia. Inversion recovery and spin-echo images were obtained in one patient with lipoma of the corpus callosum. Partial agenesis of the corpus callosum was seen in septooptic dysplasia, an association that has not been reported previously in the radiologic literature. Direct sagittal and coronal MRI provided better anatomic visualization of the brain and ventricles than did reformatted CT. T1-weighted images are sufficient to diagnose and delineate the extent of midline cerebral abnormalities. The unique capability of direct sagittal imaging makes MRI the best procedure for evaluating corpus callosal and other midline abnormalities.

Abnormalities, Multiple↗
PubMedDate not supplied

Chronic seizure disorders: contribution of MR imaging when CT is normal.

One hundred consecutive patients with complex partial seizures were studied by magnetic resonance (MR) imaging and computed tomography (CT). Thirty-four patients had seizures of more than 5 years' duration, yet neurologic examinations and previous pre- and postinfusion CT scans had been normal. MR imaging demonstrated surgical lesions of potentially therapeutic significance in four of these 34 patients. Two patients underwent surgery with removal of a thrombosed arteriovenous malformation and a glioma. Although CT has been found to detect structural abnormalities, its yield of therapeutically significant abnormalities has been low.

Adolescent↗