Biomedical subjects

C S Zee

Publications and source records attributed to C S Zee.

At least 19 recordsLinked to original sources

PubMed1992

MR imaging in rhinocerebral and intracranial mucormycosis with CT and pathologic correlation.

Three cases of mucormycosis, two in diabetics and one in an intravenous drug abuse patient, are presented. Magnetic resonance imaging proved to be useful in all cases, as was computed tomography. In one case, extremely low signal was detected from the fungal mass. It is surmised that this appearance was a result of high concentrations of iron and manganese. The low-signal area simulated air in paranasal sinuses; however, CT displayed a mildly enhancing soft tissue mass and allowed the correct diagnosis to be made. In another patient, pontine infarction was demonstrated by MR. In the third case the MR findings of mucormycosis involving the basal ganglia are shown and correlated with CT. Subsequent imaging studies demonstrated reduction of the mass, corresponding to clinical improvement.

Adult↗

PubMed1992

Cystic fluid in craniopharyngiomas: MR imaging and quantitative analysis.

A prospective study of cystic fluid in craniopharyngiomas in 10 patients was performed to correlate signal intensity on T1-weighted magnetic resonance (MR) images and biochemical analysis. Within 2 days before surgery, each patient underwent MR imaging before and after administration of gadopentetate dimeglumine. Five patients had cystic fluid lower in signal intensity than white matter, with protein levels less than 9,000 mg/dL (90.00 g/L) and no free methemoglobin. One of the five patients had the highest triglyceride concentration (84 mg/dL [0.95 mmol/L]) of all 10 patients; another of these five had the highest cholesterol concentration of all (270 mg/dL [6.98 mmol/L]). It is concluded that the increased signal intensity of cystic fluid in craniopharyngiomas on T1-weighted MR images can be caused by a protein concentration greater than or equal to 9,000 mg/dL (90.00 g/L), the presence of free methemoglobin, or both. In the ranges of concentrations measured in this study, cholesterol and triglyceride did not increase signal intensity.

Adolescent↗

PubMed1992

Radionecrosis secondary to interstitial brachytherapy: correlation of magnetic resonance imaging and histopathology.

Radiation-induced tissue damage in the central nervous system is a well-known complication of interstitial brachytherapy for brain tumors, yet imaging correlates have historically been based upon computed tomographic scans. We now present magnetic resonance imaging (MRI) to correlate radiation changes after interstitial brachytherapy with the histopathology. The central nervous system of a 38-year-old man with a left frontal cerebral glioma diagnosed by stereotactic biopsy was treated with interstitial brachytherapy (iridium-192, 47 Gy), followed by limited-field irradiation (45 Gy). With progressive deterioration, a second biopsy demonstrated radiation changes. Despite aggressive medical management, the patient died 9 months after completion of radiation therapy. Postmortem evaluation compared MRI scans of the intact, fixed brain with the histopathology. Axial sections (10 mm) obtained by MRI scan and autopsy brain slices were cut in the identical plane. Neuroimaging and histopathological findings of the lesion correlated within 2 to 3 mm resolution. In the peripheral white matter, MRI scan did not indicate the extent of radiation effect histologically. We suggest that MRI has limited utility in assessing the extent of impact of radiation on surrounding brain.

Adult↗

PubMed1992

Meningeal melanocytoma: diagnostic criteria for a rare lesion.

A case of meningeal melanocytoma, the 14th in the literature, is presented. Neurodiagnostic imaging, with both computed tomographic scan and magnetic resonance imaging, is included. Pathological examination of the tumor consisted of light microscopy, electron microscopy, and immunohistochemistry. The literature is reviewed and pathological criteria are presented to distinguish meningeal melanocytoma from meningiomas containing melanin pigment and from malignant melanoma.

Adult↗

PubMed1992

Magnetic resonance imaging and pathological correlates of meningiomas.

We examined the relationships between specific magnetic resonance imaging features and certain gross and microscopic characteristics of meningiomas, including vascularity, gross texture (consistency), and venous sinus involvement. Magnetic resonance imaging scans, surgery reports, and the histopathological findings of tumors were examined retrospectively in 54 patients. Sinus involvement was accurately predicted on T1-weighted images in 9 of 10 cases (P = 0.001) and tumors with cystic changes in 3 of 3 cases. T1-weighted images were not useful for predicting vascularity unless actual flow voids could be visualized (five of six cases). There was no correlation between T1 signal intensity, tumor consistency, or histological findings. In tumors without detectable vascularity on T1-weighted images, hyperintensity relative to gray matter on T2-weighted images was correlated with increased vascularity (P = 0.004). Tumors with soft consistency (P = 0.007), cellular atypia, invasion, angioblastic, or melanocytic components were also hyperintense, compared with gray matter on T2-weighted images (P = 0.0266). Aggressive meningiomas were found to be more vascular (P = 0.045). No correlation was found between the degree of surrounding edema or contrast enhancement with histopathological findings, vascularity, or consistency.

Brain↗

PubMed1992

Diseases of the lumbar spine: findings on fat-suppression MR imaging.

Fat-suppression MR techniques have been useful in imaging both the head and neck and the orbit. The lumbar spine is not as complex as the head and neck and does not contain as much fat as the orbit. Nevertheless, high signal from epidural and marrow fat in the lumbar spine can make it difficult to detect and define pathologic processes. In addition, the administration of gadopentetate dimeglumine can cause some infectious and neoplastic lesions of the spine to become isointense with fat on T1-weighted images. Compared with conventional MR imaging without fat suppression, contrast-enhanced fat-suppression MR imaging can better differentiate these enhancing lesions from surrounding fat. In this essay, we illustrate the findings of fat-suppression MR imaging in a variety of diseases of the lumbar spine.

Female↗

PubMed1992

The role of magnetic resonance imaging in acute transverse myelitis.

Eighteen adult patients presenting with acute transverse myelitis (ATM) were evaluated using magnetic resonance imaging. Only 7 had abnormal scans showing an area of increased signal intensity within the cord solely on T2 weighted images; T1 weighted images were normal. The MRI abnormality did not correlate with the cause of the transverse myelitis, the extent of maximum neurological deficit, or the prognosis. A scan performed more than 5 days after the onset of disease was most likely to be positive. Even though the prognostic value of MRI in ATM may be limited, it remains a valuable technique for ruling out other causes of noncompressive spinal cord lesions, such as hemorrhage, vascular malformation, or tumor.

Adolescent↗

PubMed1992

Magnetic resonance imaging of meningiomas.

MRI with gadolinium enhancement is the imaging modality of choice in the diagnosis of meningiomas. Various MRI features are described. MRI signal intensity characteristics in meningiomas contain information that could be correlated with the histopathology of the tumor. Hyperintensity on T2-weighted images indicates soft tumor consistency and microhypervascularity and is more often seen in aggressive, angioblastic, or meningothelial meningiomas. MRI is useful in demonstrating dural sinus involvement. Meningiomas in unusual locations and their mimics are also presented.

Brain↗

PubMed1991

Definition of the role of contemporary surgical management in cisternal and parenchymatous cysticercosis cerebri.

With increasing immigration from endemic regions, the incidence of neurocysticercosis in North America is rising. This retrospective study was undertaken to examine the role of surgery in those cases presenting with large cystic parenchymal and cisternal lesions in the current era of anthelminthic agents administered orally. A total of 237 patients presented with newly diagnosed neurocysticercosis to our institution over a recent 5-year period (mean age, 31.2 years). Among those who presented with cystic mass lesions predominantly affecting the brain parenchyma and cisternal spaces, 20 (8.4%; mean age, 40.2 years) with large cystic lesions subsequently underwent surgical intervention, either because of an emergent presentation or because they were refractory to medical management. Clinical presentation included increased intracranial pressure, focal neurological deficit, and seizure. Radiographic imaging (computed tomography and/or magnetic resonance imaging) demonstrated 12 cases with cisternal lesions, 7 with parenchymal lesions, and 1 involving both compartments. Based on imaging guidelines, 30 operative procedures (excluding shunt revisions) were performed (14 craniotomies, 8 cerebrospinal fluid diversions, 7 stereotactic procedures, and 1 burr hole drainage). Fifteen (75%) showed neurological or symptomatic improvement over a median follow-up period of 36.4 months. There were three surgery-related complications and no deaths.

Adult↗

PubMed1990

MRI of the skull.

Thirty-four patients with a wide variety of benign and malignant incidental skull findings on routine magnetic resonance (MR) imaging of the brain were reviewed. In most instances detection of the lesions was not difficult. However, recognition of various patterns of skull involvement in different disease processes is important. This is particularly true in differentiating benign from malignant lesions, which may be a critical factor in patient management.

Adolescent↗

PubMed1990

Magnetic resonance imaging features in melanoma.

T1 and T2 relaxation time shortening secondary to paramagnetic compounds has been described in melanoma. The purpose of this paper is to evaluate the signal behavior of melanoma involved in various body areas using short TR, TE and long TR, TE sequences. Twenty-seven sites of melanoma were evaluated with MR using T1 weighted and T2-weighted techniques. Using fat and muscle signal intensities as references tissues, lesions were graded into high, low or intermediate intensity categories for each of the sequences. Four signal patterns emerged. The typical pattern characterized by high signal on T1-weighted images and low signal on T2-weighted images reflected T1 and T2 shortening. The other pattern categories comprised of lesions demonstrating low signal T1-weighted images and high signal on T2-weighted images, high signal on both T1- and T2-weighted images and lesions showing intermediate signal on either T1- or T2-weighted images. We observed a tendency away from the typical signal pattern in extraocular melanoma cases with only one of 14 demonstrating this pattern. Moreover, only seven of thirteen ocular melanomas exhibited such behavior. Possible explanations for this findings as well as the existence of a variety of MR appearances to melanoma are offered. We conclude that while signal patterns showing T1 and T2 shortening are typical of melanoma, the absence of these does not exclude the diagnosis.

Adult↗

PubMed1990

MRI evaluation of AIDS-related encephalopathy: toxoplasmosis vs. lymphoma.

The spectrum of cranial MRI findings was evaluated in 113 patients with the acquired immunodeficiency syndrome, assessing lesion number, size, location, and configuration in association with the autopsy and/or biopsy results. Correlation of cranial MRI and CT was performed in 32 patients. MRI was shown to be superior in sensitivity of lesion detection demonstrating more lesions than CT in 14 studies (44%) and equivalent information in 18 studies (56%). In no case did CT demonstrate lesions not detected on MRI. We conclude that MRI should be the study of choice in evaluating AIDS-related encephalopathy. Multiple lesions that involve both deep gray matter and white matter suggest the possibility of CNS lymphoma. The "target" appearance on MRI is not helpful in distinguishing toxoplasmosis from lymphoma.

AIDS Dementia Complex↗

PubMed1990

Recurrent intraparenchymal hemorrhages from angiographically occult vascular malformations.

Thirteen patients with recurrent hemorrhages from angiographically occult vascular malformations are presented. Recurrent hemorrhages were indicated by the exacerbation of neurological deficits, the appearance of a new neurological deficit, or the onset of acute severe headache confirmed by evidence of recent hemorrhage on either computerized tomography or magnetic resonance imaging. Persistent neurological deficits correlated with an increased number of recurrent hemorrhages and their location. The median time from initial hemorrhage to the first recurrent hemorrhage was 12 months and the second rebleed generally occurred much earlier, with a median time of 2 months after the first. Eight patients underwent surgery with total excision and favorable results. One patient with a large pontine lesion underwent partial excision and has had a progressing neurological deficit from recurrent hemorrhages. Histopathological review confirmed the excised lesions to be cavernous angiomas. The authors conclude that angiographically occult vascular malformations are not the benign entity they were previously thought to be, and that they are prone to cause recurrent hemorrhages and persistent neurological deficits. Surgery can be effective and relatively safe in removing these lesions even in eloquent areas of the brain, but the necessity of occasional incomplete removal must be recognized in order to avoid creating an unacceptable neurological outcome.

Adolescent↗

PubMed1987

Variability in arteriographic assessment of the carotid bifurcation.

We evaluated interobserver and intraobserver variability in the arteriographic assessment of the carotid bifurcation. Two neuroradiologists evaluated area stenosis and lumen surface morphology for 60 biplane carotid arteriograms in two reading sessions. Absolute interobserver differences for area stenosis averaged 8.8%, and interobserver differences were statistically significant for arteries of at least 50% stenosis. Analysis of observations for lumen surface morphology revealed statistically significant interobserver differences, averaging 29.5% disagreement. Intraobserver differences were not statistically significant. Observer variability for arteriography should be considered in the process of evaluating patients for carotid endarterectomy.

Carotid Arteries↗

PubMed1987

Computed imaging stereotaxy: experience and perspective related to 500 procedures applied to brain masses.

The evolution of more sophisticated imaging techniques has initiated a renewed interest in stereotactic devices, methods, and applications. The Brown-Roberts-Wells instrument was available to us early in its prototype stage, and this report reviews the first 500 cases using the system at the University of Southern California Medical Center Hospitals. Procedures were undertaken after recognition of apparent structural alterations on imaging studies, with objectives being both diagnostic and therapeutic. Target locations were predominantly within the cerebral centrum-basal ganglia (284 cases) and diencephalic-mesencephalic regions (129 cases). Operative objectives included: histological and microbiological assay, cyst and abscess aspiration, installation of temporary or permanent drainage conduits, point source and colloid base brachytherapy, cerebroscopy and ventriculoscopy with biopsy, aspiration, and excision, and intraoperative vascular localization. Using multiple instrumentation at the target point (741 point placements), we realized procedural objectives in 95.6% of the cases. The mortality was 0.2% and the morbidity was 1%: hematoma, 2 cases; infection, 1 case; increased deficit, 1 case; intraprocedural seizure, 1 case. A specific diagnosis was not obtained in 4.4% (necrosis, 10 cases; inflammatory response, 9 cases; granuloma, 1 case; gliosis, 1 case; diagnostic error, 1 case). Individual guidelines for case selection, technique, institutional requirements, and applications of the method are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1986

Intracranial arterial aneurysms in childhood: more recent considerations.

Nineteen children with congenital, mycotic, traumatic and tumoral arterial aneurysms were studied neuroradiologically. The important role of computed tomography (CT) was shown in two traumatic aneurysm cases where bleeding was clinically inapparent. Among the unique cases described was a boy with a pituitary tumor in whom an aneurysm was discovered incidentally; coexistence of these lesions in childhood has not been documented previously. Nor has a tumoral aneurysm been mentioned (the case reported had a surrounding primary anaplastic sarcoma). Rare cases included a cavernous carotid mycotic aneurysm and infants with hemorrhage from congenital distal middle cerebral artery aneurysms. Marked cellular responses within the aneurysm walls, believed to be a reaction to hemorrhage, were noted in both infants.

Adolescent↗

PubMed1986

Cavernous sinus invasion by pituitary adenomas.

One hundred ninety-eight surgically explored pituitary adenomas were evaluated preoperatively by high-resolution computed tomography (CT). At surgery, evidence of direct cavernous sinus invasion was demonstrated in 19. CT findings in these cases included cavernous sinus expansion (17 patients) and visible encasement of the internal carotid artery (14 patients). The invasive tumor often enhanced to a lesser degree than the cavernous sinuses and ipsilateral internal carotid artery. Intracavernous cranial nerve compression, obliteration, or displacement (14 patients), invasion of the lateral wall of the cavernous sinus (seven patients), and diffuse bone destruction (seven cases) were other findings. Magnetic resonance imaging in three patients provided excellent demonstration of intracavernous internal carotid artery encasement, but displacement and obliteration of intracavernous cranial nerves was not shown as well as it was with CT. Histologically, only three patients showed anaplastic features and only one of them had distant metastases. There was no correlation between histologic features, hormone assays, and invasiveness. This experience indicates any type of pituitary adenoma, regardless of its endocrinologic activity, can invade the cavernous sinus. Cavernous sinus involvement makes complete surgical removal difficult. Preoperative recognition of invasive behavior of these tumors has prognostic value and aids in designing appropriate management. CT is the most useful technique generally available for evaluation and follow-up.

Adenoma↗

PubMed1986

Penetrating vascular injuries of the face and neck: clinical and angiographic correlation.

A retrospective review was made of 139 clinically stable patients who had sustained penetrating trauma to the face and neck. The study was done to learn more about the indications for angiography and the impact of angiography upon patient management. Some relationship between the physical examination and the angiographic findings was found. In the presence of any one of four physical signs or symptoms (absent pulse, bruit, hematoma, or alteration of neurologic status) there was a 30% incidence of vascular injury. However, it is unlikely that a clinically significant traumatic vascular lesion will be missed if angiography is not obtained when these clinical signs and symptoms are not present. In the group of 78 patients who presented with only a wound penetrating the platysma and no other findings or symptoms, just two had vascular injuries on angiograms; one of these lesions was minor and the other did not affect the patient's management. There was a substantially higher rate (50%) of vascular injury in patients with trauma cephalad to the angle of the mandible compared with 11% of patients who had neck trauma. Gunshot wounds were associated with vascular damage more frequently than were stab wounds.

Angiography↗