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Biomedical subjects

E Kanal

Publications and source records attributed to E Kanal.

At least 73 records · Page 4Linked to original sources
PubMed1988

MR imaging of soft-tissue hemangiomas: correlation with pathologic findings.

Soft-tissue hemangiomas have been described in MR imaging, but a histopathologic correlation to better understand the MR appearance has not been reported. Five patients with intramuscular soft-tissue hemangiomas were imaged in orthogonal planes on a 1.5-T system with spin-echo (SE) short-TR/TE sequences (600/20) and long-TR/TE sequences (2500/20-80). Complete intact surgical specimens were obtained, and gross and histopathologic findings were compared with MR findings. A striated-septated configuration with a high signal intensity on long-SE sequences (TE greater than 75 msec) correlated with endothelial-lined vascular channels separated by fibrous and/or fatty linear strands. An awareness of the morphologic MR pattern of soft-tissue hemangiomas may aid in recognition of these lesions.

Adolescent↗
PubMed1988

Comparison of MR imaging, CT, and angiography in the evaluation of the enlarged cavernous sinus.

Twenty-one patients with enlargement of the cavernous sinus were studied with CT and MR imaging. Eighteen of the patients also had cerebral angiography. MR was superior to CT in differentiating parasellar aneurysms from neoplastic masses. MR was also superior to both CT and angiography in defining the relationships of cavernous sinus neoplasms to the internal carotid artery, pituitary gland, optic chiasm, infundibulum, and fifth cranial nerves. Only in the definition of bone erosion or hyperostosis was MR inferior to another method (CT). We conclude that MR should be the initial diagnostic study in patients with symptoms of a parasellar mass, with supplementation when necessary by CT and angiography.

Adult↗
PubMed1988

Magnetic resonance imaging of spinal dysraphism.

MR imaging has become the definitive diagnostic procedure for the evaluation of suspected spinal dysrhaphic processes. Techniques for spinal MR imaging are discussed and MR findings in patients with surgically verified dysrhaphic spinal lesions are reviewed.

Child↗
PubMed1988

Pediatric musculoskeletal magnetic resonance imaging.

MRI has demonstrated clinical applicability and improved diagnostic capability in the musculoskeletal system to a degree rivaling its success in the neurologic system. For certain regions such as the joints, the superficial nature of these structures is ideal for the application of localized radiofrequency coils, enabling considerably improved signal, spatial resolution, and detectable contrast. The multiplanar capability is often invaluable in assessing such regions as the weight-bearing surfaces of the hips. It has been shown to be the most sensitive single test for diagnosing avascular necrosis, and has yielded very high resolution images of the internal architecture of the joints and soft tissues in an entirely noninvasive manner and without the need for the administration of exogenous contrast agents. Short TE images are quite useful in evaluating fatty background regions of interest, such as the bone marrow and subcutaneous tissue, whereas long TR and TE studies are frequently more suitable for soft tissue pathology. The lack of ionizing radiation and the continued failure of intensive research to disclose any deleterious effects at the levels used for clinical diagnostic imaging make this tool especially appealing for application to the pediatric population. With the continual development of new pulsing sequences, contrast agents, and further advances in imaging/spectroscopic correlation, magnetic resonance imaging of the musculoskeletal system is ensured of a solid role in the clinical diagnostic evaluation of the pediatric population.

Bone Diseases↗
PubMed1987

MR imaging of multiple hepatic cysts in a patient with polycystic liver disease.

We report a case of a 55-year-old woman with polycystic liver disease that we examined with magnetic resonance (MR) imaging, CT and ultrasound. The MR images demonstrated varying intensities in the cyst contents which we believe is due to different degrees and age of hemorrhage. Such variability among the cysts was not seen on the CT or ultrasound images.

Cysts↗
PubMed1987

Spinal and paraspinal neurofibromatosis: surface coil MR imaging at 1.5 T1.

Twelve patients with neurofibromatosis affecting the spine and paraspinal regions were examined with magnetic resonance (MR) imaging performed using a 1.5-T magnet, surface coils, and spin-echo pulse sequences. In all 11 patients with neurofibromas, these tumors had slightly greater signal intensity than muscle on T1-weighted images and markedly increased signal intensity on T2-weighted images. In seven patients central areas of decreased signal intensity within the neurofibromas were demonstrated on T2-weighted images. In one patient these central areas corresponded pathologically to relatively fibrous components of the tumors surrounded by myxoid matrix. Five patients had extensive plexiform neurofibromatosis, one had lateral meningoceles, one had a neurofibrosarcoma, three had extradural spinal cord compression, and two had cystic intramedullary tumors of the spinal cord. The ability to obtain high-resolution, multiplanar images in a noninvasive fashion makes surface coil MR imaging an ideal technique for evaluating neurofibromatosis involving the spinal cord, spinal canal, and paraspinal soft tissues.

Humans↗
PubMed1987

Orbital imaging: factors determining magnetic resonance imaging appearance.

This article addresses the dependence of the image characteristics in MR imaging of the orbit. Among the variables discussed are signal-to-noise (SNR), field of view (FOV), spatial resolution, and their interdependence. It is further shown how image contrast can be controlled by judicious choice of pulse timing parameters and how contrast depends on the intrinsic tissue MR parameters T1, T2, and proton density.

Humans↗
PubMed1986

1.5-T surface-coil MRI of the knee.

Five normal knees and 20 knees with suspected abnormalities involving the menisci or articular surfaces were examined with high-resolution surface-coil MRI. Surgical correlation was available in 15 cases. Signal-to-noise ratios were optimized using a field strength of 1.5 T and a round 7.6-cm surface coil. Spatial resolution was maximized by using fields of view reduced to as small as 8 cm. Separate examinations of the medial and lateral joint compartments were performed with the surface coil positioned vertically adjacent to the meniscus of interest. Ten meniscal tears were identified using sagittal and coronal images. T1-weighted images were adequate to detect most meniscal tears, and T2-weighted images were useful for providing an "arthrogram effect" in the presence of a joint effusion. Extrameniscal lesions that were examined included osteonecrosis of the femoral condyle, subchondral cysts, rheumatoid arthritis, degenerative arthritis, and anterior cruciate ligament tears. MRI was useful in determining the integrity of articular cartilage overlying defects in the subchondral bone and in detecting gross cartilage lesions in arthritis, but was less sensitive than arthroscopy in evaluating moderate changes in the hyaline cartilage.

Arthritis, Rheumatoid↗
PubMedDate not supplied

Policies, guidelines, and recommendations for MR imaging safety and patient management. SMRI Safety Committee.

The following are policies, guidelines, and recommendations from the Safety Committee of the Society for Magnetic Resonance Imaging (SMRI) concerning various issues related to magnetic resonance (MR) imaging safety and patient management. These policies, guidelines, and recommendations were developed to provide standardized and consistent information for use by health practitioners involved in clinical MR imaging.

Humans↗
PubMedDate not supplied

Policies, guidelines, and recommendations for MR imaging safety and patient management. SMRI Safety Committee.

The following are policies, guidelines, and recommendations from the Safety Committee of the Society for Magnetic Resonance Imaging (SMRI) concerning various issues related to magnetic resonance (MR) imaging safety and patient management. These policies, guidelines, and recommendations were developed to provide standardized and consistent information for use by health practitioners involved in clinical MR imaging.

Humans↗
PubMedDate not supplied

Guidelines and recommendations for MR imaging safety and patient management. III. Questionnaire for screening patients before MR procedures. The SMRI Safety Committee.

The authors present the third installment of the guidelines and recommendations from the Safety Committee of the Society for Magnetic Resonance Imaging (now the Society of Magnetic Resonance) concerning various issues related to the safety and management of patients undergoing magnetic resonance (MR) procedures. This document was developed to provide standardized and consistent information for use by health practitioners involved in screening patients or other individuals for MR procedures.

Artifacts↗
PubMedDate not supplied

Fast three-dimensional time-of-flight MR angiography of the intra-cranial vasculature.

Magnetic resonance angiography is most commonly performed with the three-dimensional (3D) time-of-flight (TOF) technique. As currently practiced, this requires long image acquisition times (5-10 minutes). The authors show that the acquisition time of 3D TOF images can be reduced to less than 1 minute by using a very short TR (< 10 msec). Under normal flow conditions, the major vessels of the circle of Willis were consistently well demonstrated on these fast 3D TOF images. Signal saturation was observed in studies of patients with abnormal blood flow. In those cases, it was demonstrated that serial acquisition of fast 3D TOF data during and after contrast agent administration could be used to overcome the saturation effects. Time-resolved fast 3D TOF imaging during and after contrast agent administration can also provide qualitative assessment of flow and may depict other features that cannot be observed in TOF studies with long imaging times.

Adult↗
PubMedDate not supplied

Changes in brain membrane phospholipid and high-energy phosphate metabolism precede dementia.

A 52-year-old Caucasian male was followed with Mattis and 31P MRS examinations every 6 months for 33 months. At entry into the study, the subject had a normal clinical examination and normal Mattis scores but had alterations in MRS measures of membrane phospholipid and high-energy phosphate metabolism indistinguishable from those previously reported in mildly demented AD patients. After 33 months of follow-up, the subject had clinical and Mattis findings suggestive of possible incipient dementia and after 46 months of follow-up there was sufficient cognitive decline to make the diagnosis of dementia with a frontal lobe preponderance. The findings in this subject support the contention that alterations in brain membrane phospholipid and high-energy metabolism can be noninvasively detected by 31P MRS years before any clinical manifestations of the disease.

Brain↗
PubMedDate not supplied

Magnetic ports in tissue expanders--a caution for MRI.

Although a great deal is known about the potential hazards of ferromagnetic materials relative to MRI, little has been written about the safety of tissue panders. Recently a new modification of the existing ports has been made available by incorporating a magnet for ease of identification of the injection site. Despite its low mass, the intrinsic magnetic field presents a contra-indicating factor due to the potential for torque and movement in the presence of the strong magnetic field found in the clinical MR imagers. With any evidence of tissue expander prosthesis obtained in the history, a careful questioning about the possibility of a magnetic port should be carried out.

Equipment Safety↗
PubMedDate not supplied

Renal cell carcinoma metastatic to the pituitary gland: clinical manifestations and successful treatment with transsphenoidal resection.

OBJECTIVE: To describe two cases of metastatic involvement of the pituitary gland by renal cell carcinoma (RCCA) and review the medical literature regarding this entity. METHODS: We present two case reports and discuss the published literature to illustrate the clinical findings, radiographic features, and recommended management of RCCA metastatic to the pituitary gland. RESULTS: During a 12-month period, we encountered two patients, one with visual deficits and both with anterior pituitary dysfunction, who had large sellar lesions that were histologically proved to be RCCA. Both patients were successfully treated with transsphenoidal surgical resection of the lesion, one of whom is alive and well more than 2 years later. A pituitary metastatic tumor is an uncommon complication of RCCA; it may be difficult to diagnose and potentially fatal. Anterior pituitary dysfunction and visual disturbances are more common initial features than is diabetes insipidus, in contrast to pituitary metastatic involvement from other tumors. CONCLUSION: Transsphenoidal resection is a safe and effective method of treatment of RCCA metastatic to the pituitary gland.

Journal Article↗
PubMedDate not supplied

Computer-based tutorial in MR imaging.

PURPOSE: To test the effectiveness of customized software as a teaching tool to help the novice understand basic physics concepts underlying the creation of MR images via various pulse sequences. METHODS: The authors have developed animating graphic and highly interactive electronic MR audiovisual software for the Macintosh computer in the C programming language, and have integrated it into the classroom setting for teaching MR imaging physics concepts such as T1, T2, T2*, proton density, RF excitation, TR, TE, TI, flip angle, static magnetic field strength, gradient magnetic fields, section thickness, number of phase-encoding gradients, number of excitations, field of view, intersection gap, receiver bandwidth, contrast agent(s), etc. The program interactively demonstrates the effects of these variables upon such imaging objectives as voxel dimensions, section quantity, total scanned volume, signal-to-noise ratio, contrast, contrast-to-noise ratios, resolving power, and scan acquisition time. Partial saturation, gradient echo, inversion recovery, and fat-saturation imaging techniques are included. Written posttests on the syllabus covered in our basic MR course were administered to three groups: 43 student professionals (technologist/physicist/radiologist) (control professional group) before, 149 student professionals (exposed professional group) after the addition of the tutorial software into the MR course as an integral part of the teaching process, and a group of 200 pharmaceutical sales staff with little to no prior MR or scientific background (exposed pharmaceutical group). The scores were then evaluated and compared among the groups. One hundred ten students exposed to this software also anonymously rated the software on a 1 to 5 scale (harmful to very helpful, respectively) as to their feeling regarding its role in their MR educational experience and the ease with which they were able to understand the material covered in the basic MR course curriculum. RESULTS: Mean test scores were statistically significantly lower in the Control Professional Group (60%, +/- 2.59 standard error of the mean (SEM)) than in either the Exposed Pharmaceutical (73% +/- 0.75 SEM) or Exposed Professional Groups (77% +/- 0.99 SEM). The mean subjective assessment score regarding the software was 4.8 (scale 1 to 5). CONCLUSION: This custom-developed interactive MR tutorial software is demonstrated to be effective in assisting even those new to MR imaging in understanding the concepts underlying MR imaging physics in a manner that is felt to be significantly more palatable than lectures, articles, and/or textbooks alone.

Computer-Assisted Instruction↗