PubMed Health⌕ Search

Biomedical subjects

L Nadel

Publications and source records attributed to L Nadel.

12 recordsLinked to original sources
PubMed1991

Tumoral thrombosis of cerebral venous sinuses: preoperative diagnosis using magnetic resonance phase imaging.

Intracranial, dural-based neoplasms will not infrequently invade adjacent venous sinuses. Therefore, the preoperative diagnosis of venous invasion is important, as it will alter the surgical approach to the lesion. Magnetic resonance imaging is a noninvasive means of visualizing the cerebral venous sinuses. The preoperative diagnosis of venous thrombosis can, however, be difficult and confusing with conventional spin-echo magnetic resonance imaging because of variable appearances produced by blood clot degradation products as well as flowing blood. Phase magnetic resonance imaging is a simple method that can be acquired simultaneously with conventional spin-echo sequences, and is based primarily on whether protons are stationary or moving. In the context of venous sinus occlusion, phase imaging can demonstrate the presence or absence of blood flow more easily than spin-echo imaging. Three cases of dural-based neoplasms are presented that demonstrate the utility of phase imaging in diagnosing tumoral occlusion of the venous sinuses.

Adenocarcinoma↗
PubMed1991

Intracranial vascular abnormalities: value of MR phase imaging to distinguish thrombus from flowing blood.

The interpretation of conventional spin-echo and gradient-echo MR images of intracranial vascular lesions can be complex and ambiguous owing to variable effects on image intensity caused by flowing blood or thrombus. MR phase images, obtained simultaneously with conventional-magnitude images, are useful for evaluating proton motion (i.e., blood flow), and therefore can simplify the diagnosis of the presence or absence of thrombosis within a vascular structure or lesion. Fourteen patients with a variety of intracranial vascular abnormalities (aneurysms, superior sagittal sinus thrombosis, neoplasms adjacent to venous sinuses, and vascular malformations) were evaluated with conventional MR and phase imaging for the presence of blood flow. The phase images correlated with angiography in all cases. Phase imaging was not necessarily better than conventional spin-echo imaging in all cases, but it simplified the evaluation of thrombus vs blood flow in many. In three of five aneurysms, the phase images were diagnostic for evaluating lumen patency whereas the conventional images were ambiguous. Phase imaging was advantageous for detecting tumor invasion of the venous sinus when venous blood was enhanced by gadopentetate dimeglumine. A laminar flow phantom experiment determined the lower limits of sensitivity of phase imaging to be 0.5 cm/sec in the slice-select and 2.5 cm/sec in the read gradient directions. Phase imaging is a simple, reliable technique that can distinguish thrombosis from flowing blood within intracranial lesions. It is easily performed and adds no additional time to the MR examination.

Adolescent↗
PubMed1990

MRI of intracranial sinovenous thrombosis: the role of phase imaging.

Conventional spin-echo magnetic resonance (MR) imaging of venous thrombosis is complicated by the variable appearance produced by the stage of blood clot degradation and velocity of blood flow. Phase MR imaging is a simple method based primarily on whether protons are stationary or moving. A case of superior sagittal sinus thrombosis demonstrates the utility of phase imaging.

Adult↗
PubMed1990

CT and MR imaging of the central skull base. Part 1: Techniques, embryologic development, and anatomy.

Recent advances in surgical techniques have enabled surgeons to approach previously inoperable deep-seated lesions of the skull base. The radiologist requires a thorough knowledge of the normal anatomy and the pathologic spectrum of this region and an understanding of imaging modalities in order to determine the extent of pathologic conditions and help plan the surgical approach. The embryologic development of the central skull base, normal gross anatomy, and anatomy as seen on computed tomographic and magnetic resonance images are presented.

Humans↗
PubMed1990

CT and MR imaging of the central skull base. Part 2. Pathologic spectrum.

The radiologist must have a thorough knowledge of the normal anatomy and the pathologic spectrum of the skull base to determine the extent of abnormality and to help plan the surgical approach. The authors describe and present examples of congenital, benign, and malignant lesions that affect this region, including cephalocele, fracture, fistula, juvenile angiofibroma, meningioma, chordoma, pituitary adenoma, chondrosarcoma, nasopharyngeal carcinoma, and rhabdomyosarcoma. Metastatic, infectious, and other miscellaneous processes are also discussed. Imaging strategies with computed tomography and magnetic resonance imaging to aid in the diagnosis are suggested.

Adolescent↗
PubMed1990

Perineural tumor extension through the foramen ovale: evaluation with MR imaging.

Perineural tumor extension is a form of metastatic disease in which primary tumors spread along neural pathways and gain access to non-contiguous regions. The treatment and prognosis are altered when perineural extension occurs. Awareness and proper evaluation are critical for the radiologist. The third (mandibular) division of the trigeminal nerve (V3), passing through the skull base via the foramen ovale, is a common route of perineural spread of head and neck lesions. Seven patients with perineural tumor involvement of the mandibular nerve were evaluated with magnetic resonance imaging with use of standard spin-echo pulse sequences emphasizing T1-weighted information. Three patients had adenoid cystic carcinoma, three had squamous cell carcinoma, and one had well-differentiated lymphocytic lymphoma of the orbit. MR imaging signs of perineural involvement included smooth thickening of V3, concentric expansion of the foramen ovale, replacement of the normal trigeminal cistern hypointensity by an isointense mass, lateral bulging of cavernous sinus dural membranes, and atrophy of masticator muscles.

Carcinoma, Adenoid Cystic↗