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Biomedical subjects

R D Johns

Publications and source records attributed to R D Johns.

8 recordsLinked to original sources
PubMed1988

Late appearance of a radiodense lesion at the site of an irradiated metastasis: neuropathological findings.

The appearance of contrast-enhancing computed tomographic (CT) lesions at the site of an irradiated brain tumor often has sinister implications. We present the case of a 43-year-old woman who received cranial irradiation as treatment for cerebral metastases from lung cancer. Follow-up radiographic studies revealed complete tumor regression; however, 26 months after treatment, enhanced CT scanning showed a radiodense nodule at the site of one of the previous metastatic deposits. Neuropathological examination of the surgically excised tissue identified benign reactive changes only. The natural history of irradiated brain lesions is discussed.

Adenocarcinoma↗
PubMed1988

Subarachnoid hemorrhage and normal angiography: should the angiogram be reviewed by a second neuroradiologist?

In recent years there has been a tendency to abandon repeat cerebral angiography in patients with subarachnoid hemorrhage (SAH) if the initial angiogram is normal because prognosis is said to be excellent. Our experience does not support such a conclusion. We report our experiences in 25 patients with SAH, who had a normal initial angiogram. Aneurysms were seen in five of 20 cases when angiography was repeated. On subsequent review of the initial angiograms, the aneurysm was apparent in four of the five cases. When these four initial angiograms were shown to a second observer, unaware of the results of the second study, three of the four aneurysms were correctly identified. We suggest that if, under strong clinical suspicion of SAH, the angiogram is reported as normal the study should be reviewed by a second neuro-radiologist before proceeding to repeat angiography.

Cerebral Angiography↗
PubMed1987

Neurotoxic complications of contrast computed tomography in children.

Four children with brain tumors had marked alterations in levels of consciousness and vital signs after contrast-enhanced cranial computed tomography (CT). Each had clinical evidence of increased intracranial pressure but was alert and coherent before CT. During the procedure, 2 to 2.5 mL/kg 60% diatrizoate meglumine was administered intravenously, and within hours the patients became progressively lethargic and disoriented and bradycardia and hypertension developed; two had generalized seizures. Two children died immediately after the CT procedure. Contrast-enhanced CT may produce grave neurologic complications in children with brain tumors, and this study should be reserved for those patients in whom the probability of obtaining additional information is high. Use of low-osmolality agents or nonionic contrast agents may decrease the morbidity and mortality associated with the procedure.

Brain Neoplasms↗
PubMed1981

Cerebral asymmetry in developmental dyslexia.

The computed cranial tomograms (CCTs) of 26 dextral boys with developmental dyslexia were examined for asymmetry of width and length in the frontal and occipital regions. Contrary to several previous reports, reading disability was not associated with an increase in the frequency of reversed occipital widths. There were, however, proportionately more symmetric occipital widths than expected in comparison with a control sample and previously established norms. Differences in verbal or performance IQs were not related to relative cerebral size. Language delay was also not associated with brain measurements. The CCT may be increasing in use as a tool in the investigation of children with developmental dyslexia. We conclude that CCT is not warranted unless an underlying disorder associated with significant neurologic signs is discovered by examination.

Adolescent↗