Search PubMed⌕ Search

Biomedical subjects

M H Lev

Publications and source records attributed to M H Lev.

At least 19 recordsLinked to original sources
PubMed2001

Potential influence of acute CT on inpatient costs in patients with ischemic stroke.

RATIONALE AND OBJECTIVES: Patients presenting with ischemic brain symptoms have widely variable outcomes dependent to some degree on the pathologic basis of their stroke syndrome. The purpose of this study was to determine the cost implications of the emergency use of a computed tomographic (CT) protocol comprising unenhanced CT, head and neck CT angiography, and whole-brain CT perfusion. MATERIALS AND METHODS: By using a retrospective patient database from a tertiary care facility and publicly available cost data, the authors derived the potential savings from the use of CT angiography. CT perfusion, or both at hospital arrival by means of a cost model. The cost of the CT angiography-CT perfusion protocol was determined from Medicare reimbursement rates and compared with that of traditional imaging protocols. Cost savings were estimated as a decrease in the length of stay for most stroke patients, whereas the most benign (lacunar) strokes were assumed to be managed in a non-acute setting. Misdiagnosis cost (erroneously not admitting a patient with nonlacunar stroke) was calculated as the cost of a severe complication. Sensitivity testing included varying the percentage of misdiagnosed patients and admitting patients with lacunar stroke. RESULTS: The nationwide net savings that would result from the adoption of the CT angiography-CT perfusion protocol are in the $1.2 billion range (-$154 million to $2.1 billion) when patients with lacunar strokes are treated nonacutely and $1.8 billion when those patients are admitted for acute care. CONCLUSION: The results demonstrate the potential effect of implementing a CT angiography-CT perfusion protocol. In particular, prompt CT angiography-CT perfusion imaging could have an effect on the cost of acute care in the treatment of stroke.

Cerebral Angiography↗
PubMed2001

Utility of perfusion-weighted CT imaging in acute middle cerebral artery stroke treated with intra-arterial thrombolysis: prediction of final infarct volume and clinical outcome.

BACKGROUND AND PURPOSE: The goal of this study was to evaluate the utility of perfusion-weighted CT (PWCT) in predicting final infarct volume and clinical outcome in patients with acute middle cerebral artery (MCA) stroke. METHODS: Twenty-two consecutive patients with MCA stem occlusion who underwent intra-arterial thrombolysis within 6 hours of stroke onset had noncontrast CT and CT angiography with whole-brain PWCT imaging before treatment. Infarct volumes were computed from the initial PWCT and follow-up scans; clinical outcome was measured with the modified Rankin scale. RESULTS: Initial PWCT lesion volumes correlated significantly with final infarct volume (P=0.0002) and clinical outcome (P=0.01). For the 10 patients with complete recanalization, the relationship between initial and final lesion volume was especially strong (R(2)=0.94, P<0.0001, slope of regression line=0.92). For those without complete recanalization, there was progression of lesion volume on follow-up imaging (R(2)=0.50, P=0.01, slope of regression line=1.61). All patients with either initial PWCT lesion volumes >100 mL or no recanalization had poor outcomes (Rankin scores, 4 to 6). Mean admission NIH Stroke Scale scores and mean lesion volumes in the poor outcome group were significantly different compared with the good or fair outcome (Rankin scores, 0 to 3) group (21+/-4 versus 17+/-5, P=0.05, and 106+/-79 versus 29+/-37 mL, P=0.01). Patients with initial volumes <100 mL and partial or complete recanalization all had good (Rankin scores, 0 to 2) or fair (Rankin score, 3) outcomes. CONCLUSIONS: Lesion volumes on admission PWCT images approximate final infarct volume for patients with early complete recanalization of MCA stem occlusion. For those without complete recanalization, there is subsequent enlargement of lesion volume on follow-up. Initial PWCT lesion volumes also have predictive value; volumes >100 mL are associated with a poor clinical outcome. In these highly selected patients, initial PWCT lesion volume was a stronger predictor of clinical outcome than was initial NIH Stroke Scale score.

Acute Disease↗
PubMed2001

Unique linear and nodular MR enhancement pattern in schistosomiasis of the central nervous system: report of three patients.

OBJECTIVE: The purpose of this paper is to describe the unique MR imaging appearance of schistosomiasis of the central nervous system (CNS). CONCLUSION: Contrast-enhanced T1-weighted MR images in all three patients with CNS schistosomiasis revealed a central linear enhancement surrounded by multiple enhancing punctate nodules, forming an "arborized" appearance. Pathologically, this enhancement pattern correlated with a host granulomatous response to Schistosoma species ova. Although the pattern is not present in all cases of CNS schistosomiasis, when it is observed, a diagnosis of CNS schistosomiasis should be considered.

Adult↗
PubMed2000

Imaging of cystic lesions.

Cystic neck masses are varied in their histology and embryogenesis. Because neural, vascular, and lipomatous lesions may all appear cystic, a multimodality imaging approach can help identify these potential mimics. Developmental neck cysts include thyroglossal duct, thymic, and branchial cleft cysts, and teratomatous lesions or lymphangiomas. Although laryngoceles are acquired lesions, congenital anomalies (e.g., abnormally long saccules) may play a role in their formation. Lesion location is at least as important a determinant as morphology in formulating the differential diagnosis of a cystic neck mass. Midline cystic lesions are most commonly thyroglossal duct cysts, although dermoid tumors are also frequently midline. Squamous cell carcinoma metastatic to anterior triangle lymph nodes (Fig. 17), and cystic, necrotic schwanommas, can mimic the typical appearance of an infected second branchial cleft cyst. Posterior triangle lymphadenopathy and lipomatous lesions may resemble cystic hygromas. Cystic-appearing masses in the carotid space include neurogenic tumors, vascular thromboses, and carotid chain lymphadenopathy. Neural-based lesions typically occur posterolateral to the carotid artery. Necrotic lymphadenopathy may be suggested by lesion multiplicity, or by the presence of ancillary features, such as systemic symptoms, or the existence of a primary tumor. It must be emphasized that the primary role of the radiologist in head and neck imaging is to help stage disease and guide surgery. Despite clinical and radiographic analysis, the diagnosis of many lesions ultimately depends on image-guided or excisional biopsy.

Branchioma↗
PubMed2000

Dynamic contrast-enhanced brain perfusion imaging: technique and clinical applications.

Magnetic resonance (MR) and computed tomographic (CT) perfusion imaging are evolving noninvasive imaging techniques that, unlike conventional MR and CT angiographic methods, can be used to evaluate capillary level tissue perfusion. These techniques can provide early, highly accurate delineation of ischemic tissue, allowing the underlying hemodynamic disturbances of disorders such as stroke and vasospasm to be further analyzed, as well as defining abnormal regions of blood pool in brain tumors. Because MR perfusion (MRP) and CT perfusion (CTP) imaging can assess physiologic parameters such as cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT), they offer additional data that can be useful in the detection and characterization of entities such as tumor, infection, inflammation, and infarction, which all can have similar appearances on both contrast and noncontrast enhanced conventional CT and MR images. They can also facilitate the further evaluation of processes such as early dementia, psychiatric illnesses, and migraine headaches, which may appear normal on routine CT and MR imaging. MRP and CTP might also be of value in distinguishing residual or recurrent tumor from treatment effects such as radiation-induced necrosis. This article reviews the background principles, scanning techniques, and clinical applications of noninvasive cerebral perfusion imaging.

Brain↗
PubMed2000

Computed tomographic angiography and computed tomographic perfusion imaging of hyperacute stroke.

The roles of noncontrast computed tomography (NCCT) and CT angiographic/CT perfusion (CTA/CTP) imaging in the rapid triage of clinically suspected hyperacute stroke patients to appropriate therapy is reviewed. Contraindications to thrombolysis include NCCT hemorrhage (absolute) and significant parenchymal hypodensity (relative). The sensitivity of NCCT for early (<6 h) stroke detection, higher than that of conventional magnetic resonance imaging, is improved further by using nonstandard window and level review settings. CTA/CTP is fast and convenient, adding approximately 10 min to the NCCT examination. CTA/CTP's accuracy in diagnosing ischemia and localizing thrombus to proximal or distal intracranial vessels far exceeds that of clinical examination (including National Institutes of Health stroke scale use), facilitating triage of appropriate candidates to intra-arterial thrombolysis. The size of the ischemic CTP hypodensity (proportional to reduced cerebral blood volume) predicts final infarct volume and clinical outcome; its location can guide the decision to perform intra-arterial thrombolysis, intravenous thrombolysis, or other treatment.

Angiography↗
PubMed1999

Acute stroke: improved nonenhanced CT detection--benefits of soft-copy interpretation by using variable window width and center level settings.

PURPOSE: To assess the use of nonstandard, variable window width and level review settings in computed tomography (CT) without contrast material administration in the detection of acute stroke. MATERIALS AND METHODS: Nonenhanced CT was performed in 21 patients with acute (< 6 hours) middle cerebral arterial stroke and nine control patients. Two blinded neuroradiologists rated all scans for presence of parenchymal hypoattenuation. Images were reviewed at a picture archiving and communication system (PACS) workstation, with standard, locally determined center level and window width settings of 20 and 80 HU and with variable soft-copy settings initially centered at a level of 32 HU with a width of 8 HU. Reviewers altered settings to accentuate gray and white matter contrast. RESULTS: With standard viewing parameters, sensitivity and specificity for stroke detection were 57% and 100%. Sensitivity increased to 71% with variable window width and center level settings, without loss of specificity. Receiver operating characteristic analysis revealed a significant improvement in accuracy with nonstandard, soft-copy review settings (P = .03, one-tailed z test). CONCLUSION: In nonehanced CT of the head, detection of ischemic brain parenchyma is facilitated by soft-copy review with variable window width and center level settings to accentuate the contrast between normal and edematous tissue.

Acute Disease↗
PubMed1999

Accelerated fractionated proton/photon irradiation to 90 cobalt gray equivalent for glioblastoma multiforme: results of a phase II prospective trial.

OBJECT: After conventional doses of 55 to 65 Gy of fractionated irradiation, glioblastoma multiforme (GBM) usually recurs at its original location. This institutional phase II study was designed to assess whether dose escalation to 90 cobalt gray equivalent (CGE) with conformal protons and photons in accelerated fractionation would improve local tumor control and patient survival. METHODS: Twenty-three patients were enrolled in this study. Eligibility criteria included age between 18 and 70 years, Karnofsky Performance Scale score of greater than or equal to 70, residual tumor volume of less than 60 ml, and a supratentorial, unilateral tumor. Actuarial survival rates at 2 and 3 years were 34% and 18%, respectively. The median survival time was 20 months, with four patients alive 22 to 60 months postdiagnosis. Analysis by Radiation Therapy Oncology Group prognostic criteria or Medical Research Council indices showed a 5- to 11-month increase in median survival time over those of comparable conventionally treated patients. All patients developed new areas of gadolinium enhancement during the follow-up period. Histological examination of tissues obtained at biopsy, resection, or autopsy was conducted in 15 of 23 patients. Radiation necrosis only was demonstrated in seven patients, and their survival was significantly longer than that of patients with recurrent tumor (p = 0.01). Tumor regrowth occurred most commonly in areas that received doses of 60 to 70 CGE or less; recurrent tumor was found in only one case in the 90-CGE volume. CONCLUSIONS: A dose of 90 CGE in accelerated fractionation prevented central recurrence in almost all cases. The median survival time was extended to 20 months, likely as a result of central control. Tumors will usually recur in areas immediately peripheral to this 90-CGE volume, but attempts to extend local control by enlarging the central volume are likely to be limited by difficulties with radiation necrosis.

Actuarial Analysis↗
PubMed1999

Dodecafluoropentane ultrasonic contrast enhancement in carotid diagnosis: preliminary results.

To assess the efficacy in carotid diagnosis of an investigational dodecafluoropentane ultrasonic contrast enhancing agent, we compared B-mode, color flow, and duplex Doppler findings in 16 patients with common carotid artery bifurcation disease after dodecafluoropentane and saline injections. Dodecafluoropentane produced enhanced backscatter in all patients for 4 to 20 min (mean, 8.4+/-4.74 min) after intravenous injection. In six patients this enhancement improved the color flow and pulsed Doppler signal detection in areas of sonographic shadowing. The enhanced color flow information changed the diagnostic impression in one case. Dodecafluoropentane produced enhanced backscatter in the carotid artery in all patients, and for a mean duration longer than that reported for other agents. It has the potential to improve the efficacy of carotid ultrasonic evaluation.

Aged↗
PubMed1999

Clinical applications of intracranial perfusion MR imaging.

Dynamic susceptibility MR perfusion imaging of the brain offers clinically relevant physiological data not obtainable by conventional MR imaging. As new treatments continue to be developed for stroke, neoplasm, dementia, psychiatric illness, headache, and trauma, the potential clinical applications of perfusion MR imaging in the diagnosis, triage, and therapeutic monitoring of these diseases will increase. MR perfusion techniques are likely to be at least as sensitive and specific as radionuclide-based techniques, and offer the added advantage of higher intrinsic resolution, convenient coregistration with conventional MR imaging, as well as, time and cost-effective imaging in patients for whom a routine MR imaging is obtained.

Brain Diseases↗
PubMed1999

Reduction of aneurysm clip artifacts on CT angiograms: a technical note.

We describe a head tilt technique for use with CT angiography that reduces beam-hardening artifacts in patients with aneurysm clips. This simple maneuver directs the artifacts away from pertinent anatomy, thus increasing the chances for diagnostic accuracy. No significant changes in the CT angiographic protocol are required, and the maneuver can easily be combined with other artifact-minimizing strategies.

Artifacts↗
PubMed1998

Chorea as a paraneoplastic complication of Hodgkin's disease.

Neurologic complications of Hodgkin's disease (HD) include both metastatic and non-metastatic involvement of the nervous system. There are at least five paraneoplastic syndromes associated with HD but chorea has not been described. We report the first choreiform disorder as a paraneoplastic complication of HD and only the second case of paraneoplastic chorea in the literature.

Aged↗
PubMed1998

Assessment of cerebral perfusion and arterial anatomy in hyperacute stroke with three-dimensional functional CT: early clinical results.

PURPOSE: Our purpose was to determine the clinical feasibility of quantitative three-dimensional functional CT in patients with hyperacute stroke. METHODS: Twenty-two patients who underwent clinically indicated CT angiography were studied: nine patients had no stroke, eight had mature stroke, and five had hyperacute stroke (less than 3 hours since ictus). Maps were obtained of perfused cerebral blood volume (PBV), and CT angiograms were generated by using standard techniques. RESULTS: Normal PBV values (mean +/- SEM) were 4.6 +/- 0.15% in the gray matter, 1.75 +/- 0.09% in the white matter, 2.91 +/- 0.20% in the cerebellum, 3.18 +/- 0.10% in the caudate, 2.84 +/- 0.23% in the putamen, 2.92 +/- 0.29% in the thalamus, and 1.66 +/- 0.03% in the brain stem. For patients with mature stroke, ischemic changes were visible on noncontrast, contrast-enhanced, and PBV scans. In patients with hyperacute stroke, ischemic changes were either absent or subtle before contrast administration, but became apparent on contrast-enhanced scans. Quantitative PBV maps confirmed reduced regional perfusion. CT angiograms in the hyperacute group showed occlusion of vessels in locations appropriate to the PBV deficits seen. CONCLUSION: Quantitative three-dimensional functional CT is feasible for patients with hyperacute stroke. It is performed by using helical CT techniques, and yields measures of cerebrovascular physiological function, which are useful in this patient population.

Acute Disease↗