Biomedical subjects

M T Modic

Publications and source records attributed to M T Modic.

149 records · Page 9Linked to original sources

PubMedDate not supplied

Tears of the anulus fibrosus: assessment with Gd-DTPA-enhanced MR imaging.

T2-weighted images have been shown to be capable of defining anular tears in vitro as increased signal intensity within the normal low-signal-intensity anulus fibrosus. Since growth of granulation tissue into anular tears has been described as part of the healing process, it seemed likely that gadolinium-DTPA should enhance anular tears as it does scar tissue in other parts of the spine. We retrospectively reviewed spinal MR images from 30 previously unoperated patients and correlated areas of increased signal intensity within the anulus on T2-weighted images with areas of enhancement on T1-weighted images, and to a limited extent, with surgical findings. Eighteen separate areas of anular enhancement were found in 12 patients (six cervical, 12 lumbar). Only five of these enhancing areas showed increased signal intensity on T2-weighted images, four of a type II tear pattern and one of a type III tear pattern. Contrast enhancement within the anulus was in a pattern of type II tear in 14 and type III in four. Histology from an enhancing type II anulus demonstrated vascularized granulation tissue within the avascular anulus, without focal herniation. Anular tears may be imaged in vivo not only with T2-weighted images but also with gadolinium-DTPA-enhanced T1-weighted images by virtue of their vascularized granulation tissue.

Contrast Media↗

PubMedDate not supplied

Tuberous sclerosis: increased MR detection using gradient echo techniques.

The case of a child with a pervasive developmental disorder secondary to tuberous sclerosis is presented. Magnetic resonance images demonstrated several areas of decreased signal on both T1- and T2-weighted conventional spin echo sequences. The abnormal areas became more conspicuous on the gradient echo images. The increase in conspicuity of the parenchymal brain lesions in the gradient echo images was presumably secondary to magnetic susceptibility effects.

Brain↗

PubMedDate not supplied

Cervical myelopathy: a comparison of magnetic resonance and myelography.

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.

Adolescent↗

PubMedDate not supplied

Lumbar degenerative disk disease: prospective comparison of conventional T2-weighted spin-echo imaging and T2-weighted rapid acquisition relaxation-enhanced imaging.

PURPOSE: To compare conventional T2-weighted spin-echo imaging with a rapid acquisition relaxation enhanced (RARE) technique in the routine evaluation of lumbar degenerative disk disease. METHODS: Thirty consecutive patients referred for evaluation of the lumbar spine for suspected degenerative disk disease were evaluated with sagittal and axial T1-weighted spin-echo, conventional T2-weighted spin-echo, and T2-weighted RARE "turbo spin-echo" sequences (4000/93/2 (repetition time/echo time/excitations), 192 x 256, echo train length of 8). Conventional T2-weighted and RARE images were evaluated independently by two neuroradiologists for image quality, presence of artifacts, cerebrospinal fluid signal intensity, extradural interface conspicuity, intradural nerve root conspicuity, soft-tissue detail, and signal intensity of normal and degenerated intervertebral disks. RESULTS: Both readers rated the cerebrospinal fluid signal higher, the extradural interface conspicuity higher, and the nerve root detail greater on the turbo spin-echo than on conventional spin-echo images. Neither reader had a significant difference in ranking "normal" or "degenerated" disk signal on the two sequences. Both readers rated soft-tissue detail higher for conventional than for turbo spin-echo. CONCLUSION: RARE sequences can replace conventional T2-weighted spin-echo sagittal studies for degenerative lumbar disk disease.

Artifacts↗

PubMedDate not supplied

3D MRI of the cervical spine: low flip angle FISP vs. Gd-DTPA TurboFLASH in degenerative disk disease.

The authors undertook this study to compare bright and dark CSF three-dimensional (3D) gradient-echo (GE) MR techniques to answer the following questions: Could a single Gd-DTPA enhanced T1-weighted GE volume sequence (with multiplanar reformats) be diagnostically equivalent for degenerative cervical disk disease to a standard sequence consisting of sagittal T1-weighted spin echo and axial low flip angle volume GE images (with reformatted images)? Does performing oblique coronal reformats perpendicular to the course of exiting cervical nerve roots improve diagnostic confidence over axial images alone? Thirty-one consecutive patients received a "routine" MR examination consisting of a sagittal T1-weighted spin echo and axial low flip angle volume sequence (FISP) [(35/7/5), 64 slices, 2 mm slice thickness, 192 x 256 matrix, 7.2 min]. Each patient was then given 0.1 mmol/kg Gd-DTPA intravenously, and reimaged with a T1-weighted volume GE sequence [(13/6/12), acquired as 128-1.2 mm coronal partitions, 192 x 256 matrix, 5.5 min]. Sequences were reconstructed on the standard diagnostic console in 1 mm increments. Sets of examinations (routine vs T1-weighted volume) were independently interpreted by three neuroradiologists for location, type, and severity of extradural degenerative disease. There was no strong or consistent trend for increased detection of disease by one imaging sequence over the other. For lateral disk disease, only 3% of the observations were in discordance. For disk disease, there was close agreement in the severity scores. All readers indicated that additional information was provided by the reformatted images more frequently with TurboFLASH (fast low angle shot) than with FISP. All readers indicated that increased confidence was provided by the reformatted images more frequently with TurboFLASH than with FISP. A single 3D contrast-enhanced TurboFLASH sequence is diagnostically equivalent to a set of two-dimensional T1-weighted sagittal spin echo and 3D axial low flip angle sequences for assessing the location and degree of cervical extradural degenerative disease. A screening examination of the cervical spine could be performed with a single contrast-enhanced 5.2 min study, and then relying on computer postprocessing to provide additional imaging planes.

Cervical Vertebrae↗