Biomedical subjects

C M Strother

Publications and source records attributed to C M Strother.

At least 55 records · Page 3Linked to original sources

PubMed1988

MR imaging in the management of supratentorial intracranial AVMs.

The MR images, CT scans, and angiograms of 15 consecutive patients with intracranial, supratentorial arteriovenous malformations (AVMs) were studied retrospectively. The three imaging techniques were evaluated separately to assess their utility in defining the size, characteristics, and location of the AVM nidus, its arterial supply, and venous drainage. The studies were also evaluated for their ability to show associated parenchymal abnormalities, the presence of mass effect, and changes occurring after embolization. MR was superior to both CT and angiography in showing the exact anatomic relationships of the nidus, feeding arteries, and draining veins, as well as in demonstrating the extent of AVM nidus obliteration after embolization. MR was more sensitive than CT in revealing associated parenchymal abnormalities and subacute hemorrhage. Because of flow-related artifacts and low sensitivity in distinguishing calcification from rapid flow and/or hemosiderin, MR seemed to have a low sensitivity for detecting old hemorrhage within an AVM nidus. Angiography is still needed in the planning of either surgical or endovascular treatment of AVMs.

Adolescent↗

PubMed1988

Acute posterior multifocal placoid pigment epitheliopathy associated with cerebral vasculitis.

Acute multifocal posterior placoid pigment epitheliopathy (APMPPE) is an unusual self-limited retinal disorder that has been associated with various systemic complications. To our knowledge, three prior cases associated with cerebral vasculitis have been described. This article describes a patient with APMPPE and angiographically documented cerebral vasculitis who was notable because of (a) the presence of two different cerebral ischemic events, occurring 1 month apart, and (b) the long latency (3 months) between the onset of ocular symptoms and the second cerebral ischemic event. Recognition of the association between APMPPE and cerebral vasculitis may permit early treatment of CNS involvement and prevention of morbidity.

Adult↗

PubMed1987

Cerebellopontine angle-petromastoid mass lesions: comparative study of diagnosis with MR imaging and CT.

Capabilities of computed tomography (CT) and magnetic resonance (MR) imaging in the diagnosis of cerebellopontine angle-petromastoid (CPA-PM) lesions were compared in 75 patients. CT and MR demonstrated 95.8% and 98.7% of the lesions, respectively. MR was often more helpful for characterization of neuromas, epidermoid cysts, exophytic gliomas, and vascular lesions, while CT was usually more informative for meningiomas, metastases, and tympanomastoid cholesteatomas. A specific diagnosis could be made with MR for most types of lesions through use of relaxation parameters and characteristic morphologic changes. Size, shape, location, and contour of the lesions, however, were generally more helpful for differential diagnosis than relaxation times. With the exception of metastatic lesions, cholesteatomas, and some meningiomas, MR was usually more helpful than CT in defining the full extent of the lesions and their relationships to contiguous structures. MR, because of its high accuracy in lesion detection, characterization, and localization, is a suitable primary diagnostic modality for evaluating patients with suspected CPA-PM lesions.

Brain↗

PubMed1987

Experimental and human brain neoplasms: detection with in vivo sodium MR imaging.

Elevations of intracellular sodium concentration have been observed in rapidly proliferating cells and malignant neoplasms. Sodium magnetic resonance (MR) imaging (with repetition times of 133 msec and echo times of 13, 26, 39, and 42 msec) was performed in ten patients and three dogs with central nervous system neoplasms. In all instances the neoplasms were associated with an increased sodium signal compared with that of normal brain. Unfortunately, the available echo times did not enable discrimination of intracellular sodium from extracellular sodium, which was present in high concentrations in adjacent vasogenic edema fluid. Further study is necessary to establish the utility of sodium MR imaging for the investigation of malignant neoplasms.

Animals↗

PubMed1987

New catheter for endovascular interventional procedures.

A new catheter suitable for selective angiography, embolization, and controlled infusion of chemotherapeutic agents is described. The catheter is made from a composite construction of polyethylene; it is graded in shaft thickness and outer diameter from a 2.7-F tip to a 3-F (1.0-mm) proximal section. Use of the catheter with a 0.018-inch or smaller steerable guide wire facilitates placement of the catheter in distal tortuous vessels. The catheter enabled successful completion of 20 of the 22 intracranial and extracranial intervention procedures (11 patients) in which it was used.

Catheterization↗

PubMed1987

[Aneurysms of the vein of Galen. Angiographic study and morphogenetic considerations].

The angiographic and/or anatomic study of a series of 30 cases of Vein of Galen aneurysm (which is defined as an arterio-venous fistula within the wall of the vein of Galen itself, therefore as a purely extra cerebral lesion) permits the analysis of the afferent arteries, of the efferent veins, and of the aneurysmal sac itself. The examination of the afferent arteries confirms the data from the literature, indicating that most often it consists of the abnormal hypertrophy of otherwise normally organized arteries, including the dural arteries. In particular, the involvement of distal subcallosal branches of the anterior cerebral arteries as well as the arterio-arterial maze extending above the collicular plate, fit well the normal anatomy. The venous side of the malformation nevertheless presents with more unusual features; the most striking is the non-opacification of the straight sinus and/or part of the transverse sinuses in half of the cases; also, an aberrant falcine sinus is frequently observed, which actually represents the persistence of a normal channel in the fetal anatomy. A more complex pattern was observed in two cases in which the aneurysmal sac drained into the straight sinus via a loop made of a falcine sinus, the superior sagittal sinus and then backward through a second falcine sinus. Finally, from the systematization of the afferents arteries, the aneurysmal sac appears to belong both to the (prosencephalic) velum interpositum and to the ambient cistern. Such a vessel cannot be either the true vein of Galen or an internal cerebral vein; therefore it has to be a persistent fetal vein, the median prosencephalic vein, which drains the choroid plexuses of the lateral and third ventricles between the 7th and 12th weeks, and disappears normally to be replaced by the internal cerebral veins, when the intrinsic vascularization of the neural tube develops. The adult pattern of the brain artery being attained during the 8th week, the event that led to the arterio venous fistula should have occurred some time during the 3rd month. Unfortunately, no clue was found to orient to a specific cause for the anomaly. The frequently observed venous occlusions are actually not seen in neonates but rather in older children. This, and the fact that spontaneous thromboses within the malformative veins have been observed in vivo, make likely the conclusion that venous occlusions are a secondary phenomenon only.

Adolescent↗

PubMed1986

Pineal germinoma: MR imaging.

Magnetic resonance (MR) imaging characteristics of pineal germinomas are described in seven patients imaged with MR and computed tomography (CT). In patients with symptoms of an enlarging process in the quadrigeminal plate cistern, MR imaging was as sensitive as CT scanning in detecting the mass. MR imaging did not detect a normal-sized, calcified neoplastic gland. Germinoma, germinoma with embryonal cell carcinoma elements, and pineoblastoma demonstrated different MR signal characteristics. Although direct coronal and sagittal MR images were useful in defining the relationship of the tumor to the posterior third ventricle, Sylvian aqueduct, and vein of Galen, the ease, rapidity, and sensitivity of CT scanning suggest that CT should remain the modality of choice for initial evaluation and screening of the pineal region, especially in the younger pediatric population, in whom detection of calcification may provide the only clue of an abnormality.

Adolescent↗

PubMed1986

Iotrol versus metrizamide in lumbar myelography: a double-blind study.

In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.

Contrast Media↗

PubMed1986

Clinical and experimental vasogenic edema: in vivo sodium MR imaging. Work in progress.

To investigate the sodium magnetic resonance (MR) imaging characteristics of acute vasogenic edema, an experimental canine model was developed. Vasogenic edema was produced in the hemisphere of the dogs by the intraarterial infusion of hypertonic mannitol (25%). This solution opens the blood-brain barrier, allowing the influx of water, electrolytes, and proteins into the brain. The main advantage of this model over the established "cold injury" model is the lack of associated brain necrosis. Two patients with chronic vasogenic edema secondary to well-circumscribed meningiomas also underwent MR imaging. The sodium signal was markedly elevated in both clinical and experimental studies of vasogenic edema fluid compared with signal in healthy brain tissue. Extracellular sodium associated with vasogenic edema displayed MR imaging characteristics similar to that of sodium in serum. There was a trend toward a shortened T2 in edema fluid secondary to the presence of serum macromolecules.

Animals↗

PubMed1986

Persisting abnormal embryonic vessels in intracranial arteriovenous malformations.

The study of arterial and venous anatomy of hemispheric cerebral arteriovenous malformations (AVMs) shows that, beside occlusion, rerouting of the flow, and collateral supply and drainage, the arterial and venous patterns are normal. This can be explained by the fact that the cerebral hemispheres develop late relative to other neural structures, and their fetal vessels become in fact the permanent vessels. This normality indicates that the AVMs develop after the vascular pattern has been determined. Vein of Galen aneurysms, in contrast, demonstrate occasionally an abnormal arterial pattern over the hemisphere, and retention of an embryonic vein, the median prosencephalic vein. This indicates that the fistula occurred at a much earlier stage, actually when the choroid plexuses first developed, about the end of the second month. The occurrence of choroid AVMs similar to the vein of Galen aneurysms, but drained by a normal internal cerebral vein, indicates that the time when the choroid drainage is taken over the internal cerebral vein, represents another critical period.

Cerebral Arteries↗

PubMed1986

The spectrum of multiple sclerosis lesions using a multiple spin echo pulse sequence and a high field strength.

Seventy-one patients having clinical laboratory findings consistent with multiple sclerosis (MS) were imaged with a 1.5 tesla MR instrument using multiple spin echo sequences (TR = 2,000 ms and TE = 30, 60, 90, 120 ms). Multiple spin echo is a sensitive method for detecting MS lesions. Sixty-seven patients (94%) demonstrated lesions consistent with MS. With the exception of those located in the cortex, optic nerve and chiasm the lesions detected correlated with pathologic data. Lesions of the cerebral hemispheres, corpus callosum and cerebellum were generally multiple while lesions of the brain stem and optic tracts were generally singular. The majority of the lesions were associated with the white matter tracts of the cerebral hemispheres and brain stem.

Brain↗

PubMed1985

Chymopapain chemonucleolysis: correlation of diagnostic radiographic factors and clinical outcome.

The therapeutic response to treatment of lumbar disk herniation with chymopapain chemonucleolysis is significantly influenced by the criteria used for patient selection. Although careful clinical selection of patients reduces the frequency of treatment failure, some patients do not achieve satisfactory relief of pain with chemonucleolysis. In an attempt to identify objective pretreatment radiographic findings that might refine selection criteria and further reduce the failure rate of chemonucleolysis, a retrospective correlation of pretreatment radiographs and clinical responses was made of 200 consecutive chemonucleolysis patients. Marked improvement in sciatica occurred in 79.9% and 79.3% of patients at early and late follow-up, respectively. There was a significantly higher response rate, however, in patients who had definite radiographic evidence of focal disk herniation and in those patients with definite radiographic evidence of nerve-root compression (marked nerve-root deviation, nerve-root flattening or edema, root-sleeve amputation) by disk material. Those patients with a preinjection disk height greater than the mean had a slightly better response rate (91.1%) than those whose disk height was smaller than the mean (80.0%). Most cases of treatment failure could be attributed to an incorrect radiographic diagnosis, treatment of patients with equivocal diagnostic studies, the presence of "free" disk fragments, and causes of nerve-root compression unresponsive to chymopapain.

Adult↗

PubMed1985

Chymopapain chemonucleolysis: CT changes after treatment.

Chymopapain chemonucleolysis is now used extensively in this country to treat lumbar disk herniation. Despite increasing experience in patient selection, there continue to be patients who do not respond to treatment and require diagnostic reevaluation. Interpretation of postchemonucleolysis computed tomographic (CT) scans in these patients requires a knowledge of the CT changes that normally occur after treatment with chemonucleolysis. To define these temporal changes, a prospective CT evaluation was performed of 29 treated interspaces in 26 patients who returned for routine postchemonucleolysis follow-up. Despite a successful clinical response in 17 of 21 patients, changes in the size, location, shape, homogeneity, and density of the disk herniation were uncommon at the 6 week follow-up. In 24 treated interspaces, the most common changes at 6 week CT follow-up were the development of vacuum phenomenon in three (12.5%) and a slight decrease in the size of two (8.3%) disk herniations. A successful response was noted in 17 of 21 patients scanned at 6 month follow-up, with five (22.7%) of 22 injected interspaces exhibiting vacuum phenomenon and 13 (59.1%) interspaces showing an observable decrease in the size of the disk herniation. Early improvement of sciatica after chemonucleolysis often occurs without a change in the size of the disk herniation and may be mediated by chymopapain-induced disk-space narrowing. Continued improvement may be accompanied by both a decrease in the disk height and a reduction in the size of the disk protrusion.

Adult↗

PubMed1983

Digital subtraction arteriography. A new method for evaluation of extracranial occlusive disease.

Digital subtraction arteriography (DSA) allows visualization of both the intracranial and extracranial vasculature following an intravenous injection of contrast medium. One hundred consecutive patients were evaluated using this modality. In 32, DSA was compared with conventional arteriography. The degree of internal carotid artery stenosis and/or occlusion shown by DSA was confirmed by conventional arteriography in 27 cases (84%). Abnormalities of the extracranial vasculature was demonstrated by DSA in 60% of patients with suspected cerebrovascular disease. Digital subtraction arteriography demonstrated significant stenosis or occlusion of the carotid arteries in 30% of patients in whom Doppler and radionuclide studies were normal. Digital subtraction arteriography is useful in evaluation of the extracranial vasculature in a variety of clinical conditions. In some instances it serves as a substitute for conventional arteriography. However, its exact place in evaluation of extracranial vasculature disease remains to be defined.

Angiography↗

PubMed1983

Digital subtraction angiography and continuous-wave Doppler studies. Their use in postoperative study of patients with carotid endarterectomy.

Postoperative study of 40 patients who underwent carotid endarterectomy was performed using digital subtraction angiography (DSA) and transcutaneous continuous-wave Doppler (CWD) studies. The two techniques were comparable in defining recurrent stenosis in the reconstructed carotid arteries and progressive disease in the contralateral carotid artery. Digital subtraction angiography appeared to be more sensitive than the CWD method in detecting minor progression of carotid disease. Our data suggested that CWD and DSA have comparable ability to identify significant (greater than 50%) carotid artery stenosis in this group of patients. However, DSA provided more detailed imaging of the carotid system and may give enough information about progression of carotid disease to avoid preoperative arteriography in some patients.

Angiography↗

PubMed1983

Work in progress: hybrid temporal-energy subtraction in digital fluoroscopy.

Initial clinical results using a digital fluoroscopic implementation of the combined time-energy ("hybrid") subtraction technique are described, with emphasis on carotid and renal imaging. Where patient motion artifacts are due to soft-tissue motion alone, hybrid subtraction can remove them. Due to the need for a finite separation time between high- and low-energy pairs, however, the present implementation of the hybrid technique is not completely immune to soft-tissue motion. The intrinsic signal-to-noise ratio of hybrid imaging is less than that of conventional temporal subtraction. However, since the low-energy temporal subtraction images are included in the hybrid data set, the diagnostic quality of the examination is not compromised.

Analog-Digital Conversion↗

PubMed1983

Correlation of high-resolution, B-mode and continuous-wave Doppler sonography with arteriography in the diagnosis of carotid stenosis.

One hundred thirty-one carotid bifurcations in 73 symptomatic patients were prospectively studied with high-resolution, B-mode sonography (HRS) and continuous-wave Doppler ultrasound (CWD). Twenty-three bifurcations were studied because of asymptomatic bruits, 30 for transient ischemic attacks, and 36 for focal or nonfocal symptoms or signs suggesting occlusive disease. The remaining 42 bifurcations were asymptomatic, with symptoms or signs confined to the contralateral bifurcation. Findings in the common, external, and internal carotid arteries (total, 393 vessels) were tabulated separately for plaque severity (HRS), ulceration (HRS), and degree of occlusion (HRS and CWD). HRS correctly estimated plaque severity in 67% of vessels, with 13% overestimated and 20% underestimated. HRS was only 44% sensitive for detection of 81 angiographically demonstrated ulcers. Among 187 occlusive lesions (ranges, less than 50%, greater than or equal to 50%, less than 70%, greater than or equal to 70% decrease in diameter or complete occlusion) HRS correctly estimated luminal narrowing in 62%, CWD in 30%, and HRS plus CWD in 70%. Among greater than 50% occlusive lesions, HRS was correct in 48%, CWD in 59%, and HRS plus CWD in 69%. These results suggest that (a) HRS is not accurate for diagnosis of ulceration, (b) Doppler and B-mode combined are more accurate than separate use of either procedure for evaluation of occlusive lesions, and (c) the level of accuracy in evaluating plaque and stenosis provides a general estimation of severity of disease but does not allow for precise diagnosis.

Carotid Artery Diseases↗

PubMed1983

High-resolution CT analysis of facial struts in trauma: 1. Normal anatomy.

The recent availability of high-spatial-resolution thin-section computed tomography (CT), capable of accurately depicting the thin body septa of the facial skeleton, has expanded the role that diagnostic radiology can play in the evaluation of the patient with facial trauma. A detailed knowledge of the normal CT anatomy of the face, however, is essential to optimally utilize this modality. The normal anatomy of the face was investigated in six cadavers using thin-section (1.5 mm) high-resolution CT. A systematic method of analysis that can facilitate evaluation of the face is presented. The face is conceptualized as three groups of interconnected osseous struts or buttresses that are oriented in the horizontal, sagittal, and coronal planes. Each group of struts is closely related to specific soft-tissue structures that are susceptible to injury. Sequential evaluation of each strut and its associated soft tissue assures a comprehensive evaluation of the face. While both axial and coronal sections are of value in some circumstances, the coronal ones are most helpful in accurately depicting the structures of the face that are most likely to be injured in trauma.

Face↗