A method to quantitatively measure transcapillary transport of iodinated compounds in canine brain tumors with computed tomography.

We present a quantitative method for determining a blood-to-tissue influx constant (K1), a tissue-to-blood efflux constant (k2), and tissue plasma vascular space (Vp) that uses a computed tomographic (CT) scanner to make tissue and plasma measurements of the concentration of an iodinated compound. Meglumine iothalamate was infused intravenously over time periods of 0.5-5 min, up to 49 CT scans were obtained at one brain level, and arterial plasma was sampled over a 30- to 40-min period. K1, k2, and Vp were calculated for each voxel of the 320 x 320 matrix, using a two-compartment pharmacokinetic model and nonlinear least-squares regression. The method was used in dogs with avian sarcoma virus-induced brain tumors. As many as four studies on different days were done in the same animal. In tumor-free cortex, K1 of meglumine iothalamate was 2.4 +/- 1.7 microliter g-1 min-1 (mean +/- SD) and Vp was 3.4 +/- 0.5 ml 100 g-1. Mean whole-brain tumor K1 values ranged from 3.3 to 97.9 microliters g-1 min-1; k2 ranged from 0.032 to 0.27 min-1; and Vp ranged from 1.1 to 11.4 ml 100 g-1. These values were reproducible in serial experiments in single animals. Independent verification of K1 values was obtained with quantitative autoradiographic measurements of alpha-aminoisobutyric acid, which has similar physicochemical properties to meglumine iothalamate. The CT methodology is capable of demonstrating regional variation of transcapillary transport in brain tumors and may be of value in the study of human brain tumors.

Computerized Transaxial Tomographic and Neuropsychological Evaluations in Chronic Alcoholics and Heroin Abusers

Computerized transaxial tomographic (CTT) scans and the Halstead-Reitan Neuropsychological Battery were administered to 42 paid male volunteers (15 chronic alcoholics, 15 heroin abusers, and 12 matched control subjects). CTT scans revealed that only 1 of the chronic alcoholics had a ventricle/brain (V/B) index larger than normal. One unexpected finding was that the heroin abusers had significantly smaller sulci and V/B indices. Neuropsychological assessments of the alcoholics and heroin abusers revealed functional impairment in a majority of cases; the alcoholics were twice as likely as opiate abusers to show impairment.

Optimal utilization of computerized cranial tomography and radionuclide brain imaging.

The results of computerized cranial tomography and radionuclide brain imaging in 490 patients were compared in relationship to the patients' clinical presentation. In 195 patients with focal neurologic abnormalities, both tests detected most lesions, but computerized cranial tomography was slightly more accurate overall. Results of both studies were normal in 69 percent of 295 patients with nonfocal neurologic presentations, and radionuclide imaging failed to detect lesions in only five patients with nonfocal presentations. These results suggest that radionuclide imaging can be used to accurately screen most patients with nonfocal neurologic presentations. An exception is the patient presenting with dementia, in whom computerized cranial tomography provides details of the anatomy of the ventricular cavities and cerebral cortex. This study demonstrates a continuing role of importance for radionuclide imaging in the evaluation of patients with neurologic disease and provides data to allow a rational approach to the optimum use of both techniques.

Correlation between computerized transaxial tomography and radionuclide cisternography in dementia.

A study of the findings on cisternograms and computerized transaxial tomography (CTT) of 144 patients showed good correlation between the two tests. Patients with a cisternographic pattern of communicating hydrocephalus tended to show more severe degrees of lateral ventricular dilation, with involvement of the third and fourth ventricles and relative sparing of the cerebral sulci. Patients with a cisternographic pattern of cerebral atrophy showed lesser degrees of lateral ventricular dilatation and more severe degrees of dilatation of the cerebral sulci. The statistical significance of the individual CTT findings in these patients is presented, and a cheme for interpretation is proposed. The study shows that CTT can replace pneumoencephalography in evaluating patients with dementia, while cisternography contributes complementary information.

Phagocytic capability of the kidney: a possible mechanism for renal uptake of colloid in liver-spleen scanning.

Guinea pigs were given Trypan blue or India ink i.v. and i.m. to demonstrate whether proximal convoluted tubule cells of the normal kidney have potential phagocytic capability. Circulating colloidal particles of Trypan blue solution accumulated in these cells and the accumulation was related to the particle size, dose injection, and duration of experiment. These studies suggest an explanation for the clinical observation of renal visualization with 99mTc-sulfur colloid in patients with congestive heart failure.

Migration and embolization of macrophages to the lung--a possible mechanism for colloid uptake in the lung during liver scanning.

Estrogenic stimulation of the RES in animals will result in the mobilization of large numbers of phagocytic cells from their natural sites of storage, chiefly the liver, spleen, and bone marrow, into the intravascular space. These cells are trapped in the pulmonary capillary bed and retain their ability to phagocytize colloidal particles. This is suggested to be the mechanism whereby increased lung uptake of colloidal radiopharmaceuticals is observed in some patients with liver diseases or other conditions stimulating the RES. It is further postulated that the known increase of estrogenic hormones in some patients with liver disease may be the in vivo stimulation resulting in increased mobilization of RES cells to the lung and subsequent isotope entrapment. It is possible that prognostic information can be obtained from this finding; however, its exact significance cannot be determined from this present study.

Sensitivity of radionuclide brain imaging and computerized transaxial tomography in detecting tumors of the posterior fossa: concise communication.

In a series of 25 patients with histologically proven mass lesions of the posterior fossa, computerized transaxial tomography (CTT) and radionuclide (RN) brain imaging detected 23 (92%) and 22 (88%) of the 25 tumors, respectively. In this small group of patients, the difference is not statistically significant. When the results of both techniques were combined, the detection rate was 100%, which emphasizes the complementary value of the two procedures. The two lesions not detected by CTT were metastatic carcinomas, and contrast enhancement was not employed. The three lesions not detected by RN imaging were cystic. The results may represent underestimates of the true sensitivity of both techniques since the use of contrast enhancement with CTT and of posterior flow studies and magnified static RN images of the posterior fossa would probably improve the sensitivity of both tests.

Value of routine cerebral radionuclide angiography in pediatric brain imaging.

In addition to static brain images, cerebral radionuclide angiograms (CRAGs) were performed in 1,051 children to determine the value of routine radionuclide angiography. The CRAG resulted in a statistically significant increase in detection of abnormalities (p less than 0.01), as it provided the only evidence of confirmed abnormalities in 60 children (5.7%). The CRAG helped detect subdural fluid collections, cerebrovascular disease, and cerebral cysts, but it was of little value in detecting hydrocephalus. For maximum diagnostic yield, a CRAG should be performed with all pediatric brain-imaging studies.

Supratentorial gliomas: surgical considerations and immediate postoperative results. Gross total resection versus partial resection.

Forty-two patients with supratentorial gliomas not involving the basal ganglia (extraganglionic) were studied pre- and postoperatively with computed tomographic (CT) scans to evaluate the effect of the extent of surgical resection on the immediate postoperative results. Thirty-three patients (79%) had malignant astrocytic gliomas (glioblastoma or anaplastic astrocytoma), 4 patients (10%) had well-differentiated astrocytomas, and 5 (12%) had oligodendrogliomas. The median age was 58 years, and the median Karnofsky rating was 70. There was no operative mortality. Six patients (14%) had surgical complications. A gross total resection was defined as the absence of any abnormal enhancement on the postoperative CT scan. A nearly gross total resection had been accomplished when less than 10% of the preoperatively enhancing mass was still seen. A partial resection was indicated by the presence of more than 10% of the enhancing lesion on the postoperative CT scan. A gross total or nearly gross total resection was accomplished in 36 patients (86%), and an improved or stable postoperative neurological status was present in 35 of these patients (97%). In contrast, the rate of neurological morbidity after a partial resection was 40%. Supratentorial extraganglionic gliomas, regardless of their histological type, generally were well-circumscribed lesions except at the level of the ventricular wall, where glioblastomas and anaplastic astrocytomas blended with the subependymal white matter from which they seemed to arise.

Effect of the extent of surgical resection on survival and quality of life in patients with supratentorial glioblastomas and anaplastic astrocytomas.

Thirty-one patients operated upon for supratentorial glioblastomas or anaplastic astrocytomas were studied to evaluate the effect of the extent of surgical resection on the length and quality of survival. The median age was 50 years and the median preoperative Karnofsky rate was 80. Twenty-one patients (68%) had glioblastoma multiforme, and 10 patients (32%) had anaplastic astrocytoma. Early postoperative enhanced computed tomography was used to determine the extent of tumor resection. Gross total tumor resection was accomplished in 19 patients (61%), and subtotal resection was performed in 12 patients (39%). The two groups were comparable regarding age, sex, pathological condition, preoperative Karnofsky rating, tumor location, postoperative radiation therapy, and postoperative chemotherapy (P greater than 0.05). The gross total resection group lived longer than the subtotal resection group by life table analysis (P less than 0.001; median survival of 90 and 43 weeks, respectively). Postoperatively, the mean functional ability measured by the Karnofsky rating was significantly increased in the gross total resection group (P = 0.006), but not in the subtotal resection group (P greater than 0.05). The difference in degree of change between preoperative and postoperative Karnofsky rating in the two groups was statistically significant (P = 0.002). The gross total resection group spent significantly more time after the operation in an independent status (Karnofsky rating greater than or equal to 80) compared to the subtotal resection group (P = 0.007; median time of 185 and 12.5 weeks, respectively). Gross total resection of supratentorial glioblastomas and anaplastic astrocytomas is feasible and is directly associated with longer and better survival when compared to subtotal resection.

Transsphenoidal microsurgery of pituitary macroadenomas with long-term follow-up results.

The authors have reported on 108 patients with pituitary macroadenomas (measuring 2 cm in at least one diameter) who underwent 117 transsphenoidal operations and five craniotomies, and were followed for periods ranging from 6 months to 14 years. Vision improved in 90% of the patients. Gross total tumor removal with no evidence of residual tumor tissue demonstrable on the postoperative computerized tomography scan was accomplished in 41% of cases. However, gross total tumor removal is not synonymous with complete tumor removal. Endocrine cure was possible in 25% of prolactin-secreting and 20% of growth hormone-secreting adenomas. The incidence of recurrence was 12%, with the majority occurring from 4 to 8 years postoperatively. Both the tumors with suprasellar extension of more than 2 cm and the hard fibrotic tumors had a higher recurrence rate. Postoperative administration of radiation therapy has been associated with a significantly lower recurrence rate than when this therapy was withheld. Transsphenoidal surgery of pituitary macroadenomas confined to the extra-arachnoid space is associated with a relatively small number of complications. The operative technique used in this series is described.

The lateral recess syndrome. A variant of spinal stenosis.

Sixteen patients with a surgically proven lateral recess stenosis were studied retrospectively. Lateral recess stenosis should be suspected in patients with disabling intermittent neurogenic claudications. The neurological examination is usually unremarkable. the diagnosis is assured when the lateral recess measures less than 2 mm in height. A lateral recess of 5 mm or more rules out the possibility of a lateral recess stenosis. Surgical decompression of the lateral recess requires removal of the horizontal portion of the superior articular facet.

Effect of hyperosmotic blood-brain barrier disruption on transcapillary transport in canine brain tumors.

Whether hyperosmotic blood-brain barrier (BBB) disruption is a technique that can be used to increase permeability of brain-tumor capillaries and thereby transiently increase drug delivery to the brain tumor is controversial. Nine virally induced brain tumors were studied in seven dogs, before and after hyperosmotic BBB disruption with 1.4 osmolar mannitol. Each dog was studied with computerized tomography (CT) after administration of the water-soluble tracer meglumine iothalamate. Each study lasted 30 minutes. A baseline CT scan and 35 to 40 additional CT scans were obtained to provide a time-related measurement of the amount of meglumine iothalamate in tissue (Am(t], and 30 plasma samples were collected to provide the time-related measurement of meglumine iothalamate in plasma (Cp(t]. The data were analyzed by three different methods: 1) a two-compartment model and nonlinear curve fitting were used to calculate K1 (blood-to-tissue or influx constant), k2 (tissue-to-blood or efflux constant), and Vp (plasma vascular space); 2) K1 values were calculated with a two-compartment model, assuming no efflux, at the time point for each CT scan; and 3) a "tissue advantage ratio" was calculated that expressed the ratio of tissue uptake of meglumine iothalamate at each time point, comparing values before and after BBB disruption. Regardless of which method of data analysis was used, there was a marked and significant increase in transcapillary transport of meglumine iothalamate to tumor-free brain regions, while there was only a small, transient, and insignificant increase to the brain tumors. Although there were often marked increases in delivery to cortex in the same hemisphere as the tumors, there was no significant increase to brain immediately surrounding the tumors, perhaps due to altered circulatory dynamics in this region. These data raise serious questions as to the wisdom of using this technique to increase drug delivery to brain tumors in patients and strongly support the continued study of this technique in experimental brain tumors before it is used in patients.

Current concepts in neuroradiological diagnosis of acoustic neuromas.

Two hundred twenty-one cases with clinical suspicion of a cerebellopontine angle (CPA) and/or internal auditory canal (IAC) lesions were evaluated in our hospital in the last 21/2 years by various radiological modalities. Fifty-two tumors were diagnosed and surgically removed; 48 were acoustic neuromas (33 large tumors and 15 intracanalicular small tumors) and 4 meningiomas. Polytomography detected 10 lesions out of 15 (66.7%) with 5 false-negative (33.3%) and 4 false-positive (26.7%) studies. Routine CT scan visualized large and enhancing lesions (37 out of 52), but missed the small intracanalicular tumors (15 tumors) which were only visualized by CT scan combined with cisternography or magnetic resonance imaging (MRI). MRI diagnosed 23 lesions out of 23 (100%) with no false-positive or negative studies, including 8 intracanalicular small tumors missed on the routine CT scans. MRI is far more reliable in the radiological diagnosis of CPA and IAC lesions.

Lumbar spinal-lateral recess stenosis.

The syndrome of a lumbar spinal and lateral recess stenosis is characterized by pain and a variety of paresthetic symptoms occurring principally when the patient stands or walks. Sitting or lying down alleviate the symptoms promptly. The neurologic examination is characterized by a negative straight leg-raising test and a paucity of abnormal neurologic findings. The diagnosis is confirmed by a high-resolution CT scan. If conservative treatment fails, a myelogram is in order to establish a definitive diagnosis and assess the severity of neural compression prior to placing the indication for a surgical decompression of the stenotic spinal canal. The surgical procedure consists of a laminectomy and a partial facetectomy of the hypertrophied portion of the facet joint that compresses the adjacent lumbar nerve root from a dorsal direction. It is important to recognize all associated pathologic processes that must be dealt with accordingly at the same time in order to assure success of the operative procedure. The results of a surgical decompression for a lumbar spinal and lateral recess stenosis are excellent.

Neonatal asphyxia: vulnerability of basal ganglia, thalamus, and brainstem.

Two infants who suffered acute intrapartum asphyxia resulting in severe neonatal encephalopathy are described. Although computed tomography revealed no abnormalities, magnetic resonance imaging documented unequivocal lesions in the thalamus, basal ganglia, parasagittal cortex, brainstem tectum, and midline cerebellum in one patient and in the basal ganglia and parasagittal cortex in the other. Thus, magnetic resonance imaging was more sensitive than computed tomography in detecting acute brain damage after neonatal asphyxia and may become an important tool in improving our understanding of the relationship between adverse perinatal events, neonatal encephalopathy, and neurologic morbidity.

Intracavernous carotid artery aneurysm presenting as recurrent epistaxis.

Massive epistaxis from a leaking intracavernous carotid artery aneurysm is a rare occurrence. Such an unusual case is presented with appropriate imaging and a successful treatment program.

Spinal osteomyelitis: unusual findings on magnetic resonance imaging.

In bacterial infection of the spine the intervertebral disc and its adjoining vertebral bodies are usually involved in continuity with narrowing of the disc and indistinct irregular vertebral end plates. We report a case in which the MR imaging examination demonstrated intact vertebral end plates, although the adjacent vertebral bodies and disc were involved with anaerobic streptococcus infection extensive enough to cause paravertebral inflammatory masses. Thus, intact vertebral end plates do not exclude vertebral osteomyelitis in favor of metastatic disease on MR imaging studies.