Dennis Osborne

Transient Cerebral Ischemia as a Manifestation of Ruptured Intracranial Dermoid Cyst

Transient cerebral ischemia was the initial manifestation of a ruptured intracranial dermoid cyst in a young adult male. The ischemia could have resulted from vasospasm caused by release of the contents of the dermoid cyst into the subarachnoid space or from other local effects of the tumor. The role of computed tomography in the evaluation of patients with transient cerebral ischemia is discussed.

Dynamic Computed-Tomography Study of the Brain

The dynamic computed tomography (CT) study of the brain consists of the rapid intravenous injection of 49 ml of radiographic contrast material in 7 sec followed by serial 5 sec CT scans with interscan times of only I see. The data from these scans can be reprocessed to create 12 segmented images in 35 see. When small samples of four to six pixels of cortex are examined by the cursor, sharp rises of 20 to 25 CT units (500 scale) are seen on the time–density curves. Samples of while matter are usually no more than 2 CT units. When larger cursor samples of 220 to 255 pixels including cortex and white matter are examined, the time – density curves represent a combination of these two patterns. Comparison between symmetrical areas in the two hemispheres generally shows parallel curves in controls. The studies provide high resolution cerebral perfusion images. In ischemia secondary to ipsilateral carotid stenosis, there is depression of the up-slope and a depressed and late peak. Infarctions show a flat perfusion curve. Several patterns in brain tumors are illustrated. The study, simple to perform, adds significant perfusion information to the previously static CT examination of the brain.

CT-guided stereotactic biopsies using a modified frame and Gildenberg techniques.

Eighteen patients underwent CT guided stereotactic biopsies using either a Riechert-Mundinger stereotactic frame modified for use in the CT scanner or the CT-based intracranial landmark technique of Gildenberg and a Todd-Wells frame. In seven patients undergoing biopsy with the modified frame technique, representative tissue samples were obtained in all cases. Eleven patients had biopsies using the Gildenberg technique and representative tissue samples were obtained in 10 of the 11. No major postoperative complications occurred in either group. Both techniques allowed samples of intracranial tissue to be obtained safely and efficiently. The modified frame technique provided a higher degree of accuracy while the Gildenberg technique required significantly less CT time and provided a satisfactory degree of accuracy. In seven patients with ring enhancing lesions, biopsies of the enhancing rim provided diagnostic tissue while biopsy of the central low density center of the lesion in three patients provided necrotic material which was useful in histologically grading the tumour.

Evaluation of memory and language function pre- and postthalamotomy with an attempt to define those patients at risk for postoperative dysfunction

Memory and language dysfunction has been sporadically reported following stereotaxic thalamotomies. In order to determine which patients are at greatest risk and to better define the nature of this dysfunction, we have prospectively evaluated 18 patients undergoing stereotaxic thalamotomies for movement disorders (MDs). Patients were evaluated clinically, with computed tomography (CT) and with memory and language protocols (MLPs) pre- and postoperatively. Patients exhibiting postoperative deficits were again evaluated with the MLP on follow-up visits to the clinic. Significant changes in memory and language function occurred in 7 out of 18 patients. These 7 patients had diverse etiologies for their MDs. Five of the 18 patients had undergone previous thalamotomies on the contralateral side. Three of these 5 patients with bilateral thalamotomies experienced postoperative functional impairments in memory and language while only 4 of 13 patients with a unilateral thalamotomy experienced these problems. The postoperative functional impairments noted were primarily those requiring orientation and speech. All patients with postoperative memory and language impairments were again evaluated with MLPs months after the operation. In 3 of 7 patients, no improvement was noted, while the remaining 4 did recover to baseline. More severe deficits tended to occur in those patients with ventriculomegaly or evidence of other major cerebral tissue loss by preoperative CT scan and in those patients with lower MLP scores preoperatively. Postoperative memory and language dysfunction was not correlated with the number or size of the lesions made, the postoperative general neurologic examination or CT scans, or the clinical response of the MDs. From our data, it appears that patients with more profound neurologic compromise and/or bilateral involvement as evidenced by poor performance on the MLP, tissue loss on CT scanning, or previous thalamic lesion, are most at risk for memory and language dysfunction postoperatively. However, this dysfunction is not necessarily permanent. Preoperative evaluation with MLPs and CT scanning appear to be of value in predicting those patients at greatest risk for postoperative and language dysfunction.

The role of seminal vesiculography in the evaluation of male infertility.

Although most cases of male infertility are the result of primary testicular abnormalities (either maturation arrest, decreased spermatogenesis, or germinal hypoplasia), obstruction of the genital tract is a well recognized and potentially correctable cause of infertility. Seminal vesiculography is an excellent method of evaluating the male genital tract not only for obstruction but also for other structural lesions that may cause infertility. In 27 patients undergoing vesiculography as part of an evaluation of infertility, obstruction was found in 25%. Three patients (11%) were found to have nonobstructing structural lesions as a possible cause of infertility. Patients with obstructive lesions were found to have significantly lower semen volumes than those with patent outflow tracts. The continued role of seminal vesiculography in the evaluation of male infertility is discussed.

Atypical Findings in Adrenoleukodystrophy

: Computed tomography (CT) in a child with typical clinical and biochemical features of adrenoleukodystrophy (ALD) revealed striking pathologic enhancement in the centra semiovalia, posterior corpus callosum, and corticospinal tracts within the internal capsules, cerebral peduncles, and basis pontis. Central calcifications were detected within otherwise typical symmetrical low attenuation lesions in the periatrial white matter. These findings further expand the spectrum of CT abnormalities in ALD and may represent a link between the recently described Type 1 and Type 11 CT patterns.

Role of computed tomography in the radiological evaluation of painful radiculopathy after negative myelography: foraminal neural entrapment.

Thirty-five patients with an unremarkable or a negative water-soluble contrast myelogram and a diagnosis of foraminal neural entrapment made or more firmly established by computed tomography (CT) were detected in evaluating 950 patients presenting for myelography. The CT criterion of foraminal neural entrapment was the presence of a mass displacing epidural fat and encroaching on the neural intervertebral foramen or lateral recess so as to compromise an emerging nerve root. The entrapment (confirmed operatively) was due to a laterally prolapsed disc (16 cases), superior articular hypertrophy (4 cases), lateral recess stenosis (3 cases), posterolateral vertebral bone lipping (2 cases), tumors (6 cases), postoperative scarring (2 cases), spondylolisthesis (1 case), and synovial cysts that encroached on the neural foramina (1 case). CT is an important additional investigation in patients with a painful radiculopathy and a negative or equivocal water-soluble contrast myelogram.

Further experience utilizing the Gildenberg technique for computed tomography-guided stereotactic biopsies.

Initial experience using the Gildenberg technique for computed tomography-guided stereotactic biopsies is reviewed. Of 50 patients, adequate tissue was obtained in 49. In one patient, the stereotactic frame was unable to reach the selected biopsy site. In 32 of 49 patients, the diagnosis was obtained with one biopsy; in the remainder, two to five samples were required. In 4 cases, a subsequent craniotomy was performed; these provided similar histopathological tissue and in no case was the diagnosis altered. The lesions were categorized by CT as ring-enhancing lesions (REL), enhancing lesions with surrounding low density (ELLD), and low density lesions with and without peripheral areas of enhancement. Of the REL, 21 of 23 were primary tumors. Of the ELLD, 5 of 13 were primary tumors; the remainder had a wide spectrum of disease. Of the low density lesions without enhancement, 6 were primary tumors and 1 was an inflammatory process. Three patients had low density lesions with peripheral areas of enhancement and proved to have malignant primary tumors. The remaining patients had multiple lesions with both primary and metastatic disease. Twelve RELs were biopsied in multiple sites. An accurate diagnosis was best obtained by performing the first biopsy in the enhancing rim with additional biopsies as needed in the low density center. Homogeneous lesions could be biospied with target selection based upon a primary regard for safety rather than imaging characteristics. Three patients had transiently increased hemiparesis and one had a transient decrease in level of consciousness after biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Computed tomography of sarcoidosis of the optic nerve

SummaryTwo patients with optic nerve sarcoidosis, one proven by an open biopsy of the optic nerve, the other by clinical evidence of sarcoidosis and a positive conjunctival biopsy, were examined by computed tomography. In both cases increased diameter and pathological enhancement of the involved optic nerves were demonstrated.

Rapid serial cranial computed tomography for tumor diagnosis

SummaryRapid serial computed tomography (RSCT) provides more information about the cerebral cortical capillary bed and leptomeningeal vessels than conventional enhanced computed tomography (CT). This increased neuroanatomical definition has potential value for separating intra- from extracerebral tumors in selected cases. RSCT offers better visualization of the angioarchitecture of highly vascular tumors than conventional enhanced CT. However, CT scans delayed several minutes after contrast administration are more useful for evaluating the extent of hypovascular tumors. Time-density curves were of limited value for tumor evaluation. However, the peak increase of Hounsfield units did correlate well with the degree of tumor vascularity assessed angiographically.