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N J Fischbein

Publications and source records attributed to N J Fischbein.

At least 19 recordsLinked to original sources
PubMed2001

The role of isotropic diffusion MRI in children under 2 years of age.

Our objective was to determine the contribution of diffusion MR imaging to standard MR imaging in the neuroradiological evaluation of children less than 2 years of age. Echo-planar diffusion MR imaging was added to standard MR exams in 75 consecutive patients under the age of 2 years. Single-shot echo-planar spin-echo T2 weighted images (EPSE-T2) were acquired. Isotropic diffusion-weighted images (DWI), attenuation coefficient maps (ACM), and apparent diffusion co-efficient (ADC) maps were calculated offline from images obtained with diffusion gradients (b = 1000 s/mm2) in three orthogonal directions. Two neuroradiologists determined if EPSE-T2, DWI, or ACM contributed new information to spin-echo proton density (SE PD) and T2 studies. In 15 of 18 abnormalities detected in 8 patients with symptoms less than 1 week in duration, DWI and/or ACM added information to SE PD and T2. Diffusion sequences detected five new lesions, showed six lesions with greater conspicuity, and identified four lesions with different diffusion character. In patients with symptoms of more than 7 days duration, diffusion studies added no information. Isotropic diffusion MR contributed to lesion detection and characterization in infants when symptoms were less than 1 week in duration. Diffusion MR is useful in patients with leukodystrophies, metabolic disorders, and patients with acute ischemic lesions.

Adult↗
PubMed2001

MR imaging in two cases of subacute denervation change in the muscles of facial expression.

SUMMARY: Denervation changes in muscle following damage to cranial and peripheral nerves can be observed on both CT and MR imaging studies. These findings are well described for cranial nerves (CN) V, X, XI, and XII. The CT findings of denervation atrophy due to CN VII dysfunction have been reported. We describe the MR imaging findings in two patients with perineural spread of tumor along CN VII. Both patients showed T2 prolongation and postcontrast enhancement in muscles of facial expression, suggestive of subacute denervation changes.

Aged↗
PubMed2000

Correlation of clinical and neuroimaging findings in a case of rabies encephalitis.

BACKGROUND: Rabies encephalitis is a feared, virtually uniformly fatal form of central nervous system infection. The incidence of rabies encephalitis in the United States is almost certainly underestimated because of the predominance of bat-borne rabies, which can be spread without traumatic exposure. Because of its rarity in developed countries, rabies encephalitis has been seldom studied with modern imaging techniques. SETTING: University-based teaching hospital. PATIENT: A case of pathologically confirmed rabies encephalitis is presented. Diagnosis of rabies was made by seroconversion testing while the patient was alive and was confirmed postmortem by the presence of rabies antigens and Negri bodies in the brain. The patient had 2 magnetic resonance studies done that showed dramatic abnormalities in the medulla and pons that correlated with features of the neurologic examination and hypothalamic-pituitary abnormalities. RESULT: The patient had a fulminant encephalitic course that ended in death. CONCLUSION: Rabies is an uncommon cause of fatal encephalitis. Anatomic imaging studies such as computed tomographic and magnetic resonance scans have generally been negative in confirmed cases of rabies. We report a case of confirmed rabies with extensive brainstem and hypothalamic-pituitary abnormalities on magnetic resonance imaging. Although these findings are nonspecific, they should raise the clinical suspicion of rabies in the setting of aggressive encephalitis of unclear cause, and appropriate diagnostic tests should be performed.

Adult↗
PubMed2000

Comparison of relative cerebral blood volume and proton spectroscopy in patients with treated gliomas.

BACKGROUND AND PURPOSE: Elevated relative regional cerebral blood volume (rCBV) reflects the increased microvascularity that is associated with brain tumors. The purpose of this study was to investigate the potential role of rCBV in the determination of recurrent/residual disease in patients with treated gliomas. METHODS: Thirty-one rCBV studies were performed in 19 patients with treated gliomas. All patients also had proton MR spectroscopy and conventional MR imaging. Regions of abnormality were identified on conventional MR images by two neuroradiologists and compared with rCBV and MR spectroscopic data. Metabolites and rCBV were quantified and compared in abnormal regions. RESULTS: In high-grade tumors, rCBV values were proportional to choline in regions of tumor and nonviable tissue. Although the presence of residual/recurrent disease was often ambiguous on conventional MR images, the rCBV maps indicated regions of elevated vascularity in all low-grade tumors and in 12 of 17 grade IV lesions. Regions of elevated and low rCBV corresponded well with spectra, indicating tumor and nonviable tissue, respectively. CONCLUSION: This study suggests that rCBV maps and MR spectroscopy are complementary techniques that may improve the detection of residual/recurrent tumor in patients with treated gliomas. Compared with the spectra, the rCBV maps may better reflect the heterogeneity of the tumor regions because of their higher resolution. The multiple markers of MR spectroscopy enable better discrimination between normal and abnormal tissue than do the rCBV maps.

Adult↗
PubMed2000

Recurrence of clival chordoma along the surgical pathway.

Chordomas are locally aggressive malignant tumors of notochordal origin whose metastatic potential is increasingly recognized. Surgical pathway recurrence has been noted only rarely in the literature. We present three patients with clival chordomas whose sole or initial recurrence was along the pathway of prior surgical access. A characteristic mass found along the pathway of prior surgical access for resection of a chordoma should suggest recurrent chordoma.

Adult↗
PubMed1999

Magnetic resonance imaging of the central skull base.

The central skull base is an anatomically complex region whose foundation is the sphenoid bone. It includes the sphenoid sinus, clivus, and sella turcica, as well as adjacent soft tissues such as the cavernous sinuses and nasopharynx. The central skull base may be affected by pathologies intrinsic to the sphenoid bone or by processes that arise in adjacent soft tissue and extend centrally to affect the central skull base. In general, this region is optimally imaged with magnetic resonance scanning, although in some cases computed tomography can provide complementary information. In this review, we will discuss a variety of pathologies that can affect the central skull base, such as neoplasms, infections, trauma, congenital malformations, and a variety of miscellaneous pathologies. We will discuss processes that can mimic neoplasia, such as aggressive polyposis and chronic inflammatory disease. For each pathology we will review clinical and imaging findings.

Diagnosis, Differential↗
PubMed1999

Metastatic head and neck cancer: role and usefulness of FDG PET in locating occult primary tumors.

PURPOSE: To assess the usefulness of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) of the head and neck in locating occult primary lesions in patients with metastatic cervical adenopathy. MATERIALS AND METHODS: Seventeen patients with metastatic cervical adenopathy of unknown primary origin were referred for FDG PET of the head and neck. All patients had undergone correlative anatomic imaging within 1 month of FDG PET. Surgical, clinical, and histopathologic findings were used to assess the performance of FDG PET. RESULTS: Increased apical lung uptake at FDG PET led to a biopsy-proved diagnosis of primary lung cancer in two patients. Of the remaining 15 patients, 10 had a focus of increased activity; directed biopsy of these sites led to confirmation of a primary carcinoma in seven patients. Correlative anatomic imaging failed to demonstrate the primary sites of disease in two of these seven patients. None of the five patients with negative FDG PET studies have manifested evidence of a primary site of disease during follow-up of 8-42 months (mean, 29 months). CONCLUSION: FDG PET allows effective localization of the unknown primary site of origin in metastatic head and neck cancer and can contribute substantially to patient care.

Adenocarcinoma↗
PubMed1999

The "presyrinx" state: a reversible myelopathic condition that may precede syringomyelia.

BACKGROUND AND PURPOSE: Alteration of CSF flow has been proposed to be an important mechanism leading to the development of syringomyelia. We hypothesize that a "presyrinx" condition attributable to a potentially reversible alteration in normal CSF flow exists and that its appearance may be caused by variations in the competence of the central canal of the spinal cord. METHODS: Five patients with clinical evidence of myelopathy, no history of spinal cord trauma, enlargement of the cervical spinal cord with T1 and T2 prolongation but no cavitation, evidence of altered or obstructed CSF flow, and no evidence of intramedullary tumor or a spinal vascular event underwent MR imaging before and after intervention that alleviated obstruction to CSF flow. RESULTS: Preoperatively, all patients had enlarged spinal cords and parenchymal T1 and T2 prolongation without cavitation. Results of MR examinations after intervention showed resolution of cord enlargement and normalization or improvement of cord signal abnormalities. In one patient with severe arachnoid adhesions who initially improved after decompression, late evolution into syringomyelia occurred in association with continued CSF obstruction. CONCLUSION: Nontraumatic obstruction of the CSF pathways in the spine may result in spinal cord parenchymal T2 prolongation that is reversible after restoration of patency of CSF pathways. We refer to this MR appearance as the "presyrinx" state and stress the importance of timely intervention to limit progression to syringomyelia.

Adult↗
PubMed1998

Sturge-Weber syndrome with no leptomeningeal enhancement on MRI.

Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome characterized by a facial nevus flammeus associated with seizures, developmental delay, and, often, with hemiparesis and hemianopia. On MRI, the most characteristic finding has been reported to be leptomeningeal enhancement, believed to represent leakage of contrast medium through the anomalous pial vessels that characterize the disease. We present a case of SWS with no evidence of leptomeningeal enhancement. This case illustrates that leptomeningeal enhancement need not be present in SWS, and the absence of this characteristic finding does not preclude the diagnosis.

Adolescent↗
PubMed1998

Endoscopic third ventriculocisternostomy: MR assessment of patency with 2-D cine phase-contrast versus T2-weighted fast spin echo technique.

PURPOSE: To determine if fast spin-echo T2 (FSE) is of equal value to flow-sensitive 2D cine phase-contrast (CPC) to assess patency of endoscopic third ventriculocisternostomies (VC). PATIENTS AND METHODS: We reviewed clinical charts and MR scans of 27 patients who underwent third VC for treatment of obstructive hydrocephalus. Thirty-nine postoperative scans included both sequences and were assessed for the presence or absence of flow-related signal changes. RESULTS: In 28 cases, FSE, CPC, and clinical findings suggested patency. In 1 case, CPC and FSE suggested occlusion, which was confirmed clinically and operatively. In the remaining cases, FSE showed better clinical correlation than did CPC. CONCLUSION: The assessment of third VC patency with FSE, a sequence available on most clinical scanners without a requirement for special hardware and software, is at least as sensitive in the qualitative assessment of VC function as CPC.

Adolescent↗
PubMed1998

Clinical utility of positron emission tomography with 18F-fluorodeoxyglucose in detecting residual/recurrent squamous cell carcinoma of the head and neck.

PURPOSE: The use of positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) to detect residual/recurrent squamous cell carcinoma of the head and neck has been tested only in small groups of patients. Our purpose, therefore, was to evaluate the ability of this technique to detect the presence of tumor at both primary and nodal sites in a large cohort of patients. METHODS: All patients referred for PET scanning over a 2.5-year period with a question of residual or recurrent squamous cell carcinoma of the head and neck were identified. Thirty-five of 44 patients had sufficient follow-up to be meaningful to our analysis (range, 6-33 months). PET scans were interpreted visually with knowledge of the clinical history and correlative anatomic imaging findings. Detection of disease involving primary and nodal sites was assessed independently. Additionally, because each patient had been referred in an attempt to resolve a specific clinical problem, the usefulness of PET in accurately addressing these questions was assessed. RESULTS: At the primary site, sensitivity and specificity for residual/recurrent disease were 100% and 64%, respectively; for nodal disease, sensitivity and specificity were 93% and 77%, respectively. In helping to resolve the clinical question being asked, the positive predictive value of the test result was 65% and the negative predictive value was 91%. CONCLUSION: The high sensitivity and negative predictive value of PET scanning in our cohort of patients suggest an important role for this technique in the care of patients with suspected residual/recurrent head and neck carcinoma. The lower figures obtained for specificity and positive predictive value reflect the fact that increased FDG uptake may be due to either tumor or inflammation.

Adult↗
PubMed1997

Imaging of otolaryngologic manifestations of HIV infection.

Patients infected with HIV have severely depressed immune function and are therefore vulnerable to many infectious and neoplastic processes. Head and neck manifestations initially were reported in approximately 40% of patients with AIDS, but in the course of HIV infection and progression to full-blown AIDS, it is now recognized that most patients have abnormalities on head and neck examination at some point in their disease. These manifestations range from relatively benign lymphoid hypertrophy or candidal mucositis to life-threatening fungal infections and high-grade lymphomas. This article reviews the spectrum of imaging findings associated with otolaryngologic diseases in this patient population.

AIDS-Related Opportunistic Infections↗
PubMed1996

Radiologic classification of brain stem tumors: correlation of magnetic resonance imaging appearance with clinical outcome.

Although tumors of the brain stem have traditionally been classified as a single entity, these tumors are increasingly being recognized as a heterogeneous group, with some subgroups having better prognoses for long-term survival. Although several systems for classification of brain stem tumors have been proposed, none have been based on data derived from contrast-enhanced magnetic resonance (MR) imaging. In this review, we present a classification scheme based on our review of the literature and of the MR scans of 64 patients with brain stem tumors. In addition, we assess the contribution of gadolinium to the classification of brain stem tumors and correlate the various tumor subtypes, based on MR appearance, with prognosis. Our results suggest that the most important factor in determining prognosis based on MR characteristics is whether the tumor is diffuse or focal. Focal tumors have an excellent prognosis regardless of the site of tumor origin. Diffuse tumors of the mesencephalon and pons have a significantly poorer prognosis than focal tumors (p = 0.0013), with diffuse pontine tumors having the worst prognosis. Differentiation of diffuse and focal medullary tumors was difficult, possibly explaining the lack of significant difference in the survival of patients with diffuse versus focal medullary tumors. The presence or absence of enhancement after the administration of paramagnetic contrast has no significant relation with outcome, overall or within specific tumor subgroups.

Adolescent↗
PubMedDate not supplied

Multisection dynamic CT perfusion for acute cerebral ischemia: the "toggling-table" technique.

A new CT perfusion technique providing extended anatomic coverage was evaluated in 12 patients with suspected acute middle cerebral artery ischemia. With a multidetector CT scanner, scans were obtained in an alternating fashion at two distinct "toggling" table positions (two 1-cm sections each) during a 40-mL contrast agent bolus (approximately 5 seconds per image), and perfusion parameter maps were created. The CT perfusion results were compared with follow-up images. Nine patients showed focal perfusion abnormalities in at least one section, most commonly on mean transit time maps. Using a single table location would have underestimated or missed the involved tissue in most cases. In three of 12 patients, perfusion maps failed to delineate any abnormality. In two patients, perfusion and diffusion MR imaging confirmed the absence of perfusion abnormality and tissue injury, respectively. In one case, a small ischemic injury was revealed by diffusion MR imaging. By using the toggling-table approach, perfusion images can be obtained over an extended anatomic area and, thus, reveal the presence and the extent of presumed tissue injury.

Brain Ischemia↗