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Biomedical subjects

M T Modic

Publications and source records attributed to M T Modic.

At least 91 records · Page 5Linked to original sources
PubMed1986

Natural history of the vascular dementias: a prospective study of seven cases.

The clinical course of vascular dementia has been described as a stepwise deterioration over time. We studied the chronologic course of cognitive performance over 1-4 years in seven patients with known ischemic cerebrovascular disease whose dementia subtype was assigned according to the clinical history and the pattern of white matter lesions seen on magnetic resonance imaging (MRI). One patient had the lacunar state, three had subcortical arteriosclerotic encephalopathy and three had multiple cortical and subcortical strokes. All were being treated with an antiplatelet agent and six received antihypertensive therapy. Four of the seven vascular dementia patients improved cognitively over the first year. A fluctuating course was eventually seen in all patients. None showed stepwise deterioration of cognitive function over time. The MRI was useful in subclassifying vascular dementia patients, but the clinical course did not appear to vary as a function of the dementia subtype.

Aged↗
PubMed1986

Cervical radiculopathy: prospective evaluation with surface coil MR imaging, CT with metrizamide, and metrizamide myelography.

A prospective study was undertaken to compare the accuracy of surface coil magnetic resonance (SCMR) imaging, metrizamide myelography (MM), and computed tomography with metrizamide (CTM) in the determination of cervical radiculopathy. Surgical findings were the objective measure of accuracy. Fifty-two patients underwent all imaging studies. Studies were evaluated for disease location and type (bone vs. soft tissue). Twenty-eight patients underwent subsequent cervical surgery at 39 levels form an anterior interbody approach. Predictions made with SCMR imaging were surgically confirmed in 74% of patients, with CTM in 85%, and with MM in 67%. There was 90% agreement with surgical findings when SCMR imaging and CTM were used jointly, and 92% agreement when CTM and MM were used jointly, In general, SCMR imaging was as sensitive as CTM for identification of disease level, but not as specific for type of disease. MM was the modality least specific for disease type. The major advantage of CTM was its ability to distinguish bone from soft tissue, for which contrast material is unnecessary. SCMR imaging is a viable alternative to MM and, together with computed tomography, if needed, provides a thorough examination of the cervical region.

Adult↗
PubMed1986

Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography.

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.

Adult↗
PubMed1986

Magnetic resonance imaging of the spine.

Magnetic resonance imaging has been applied to the evaluation of the spine and foramen magnum and has clearly shown not only that it can demonstrate the normal spinal anatomy and a variety of pathologic conditions, but also that it can be performed safely in a noninvasive fashion in an outpatient setting. Although MRI is presently a valuable adjunct to more conventional diagnostic studies of the spine, it is the imaging examination of choice in several suspected disease entities.

Abscess↗
PubMed1986

Magnetic resonance imaging of musculoskeletal infections.

In summary, MRI has a high sensitivity for the detection of inflammatory disease involving the musculoskeletal system. Because of the usual anatomic pattern of involvement in the vertebral column, there is also a high specificity. In the appendicular skeleton and pelvis, it is unclear whether MRI can add to the sensitivity and specificity of radionuclide studies in uncomplicated cases of acute infection. However, it can be performed more rapidly and provides greater anatomic detail and delineation of the extent of marrow involvement than radionuclide studies. MRI can be used in both acute and chronic osteomyelitis to guide a diagnostic interventional test to the appropriate site. It is capable of excluding involvement of the medullary canal, and it is better than radionuclide studies for differentiating soft tissue infection with periostitis from osteomyelitis. It has only a limited role in the immediate postoperative period, and in the presence of metallic implants, an indium-labeled leukocyte scan may be more appropriate. Finally, it must be remembered that the current data base of MRI is small and that further refinement of its role in the evaluation of inflammatory processes will be forthcoming.

Adult↗
PubMed1985

The intranuclear cleft of the intervertebral disk: magnetic resonance imaging.

Three cadaver spines, 40 patients who were symptomatic for lumbar disk disease, and ten healthy subjects were examined by MR. T2 weighted spin echo images were used to evaluate the character of an intranuclear cleft. This cleft appears identical to annular tissue both on T2 weighted images and histologically. A 120 msec TE, 3 sec TR image was used to delimit the normal nucleus pulposus from the annulus. The incidence and age distribution of the cleft were calculated. An intranuclear cleft was present in all normal disks in both control and symptomatic subjects who were 30 years of age and older. If present in one disk, it was also present in 94% of the other disks in the same subject. This cleft represents a normal anatomic structure and appears to be a constant feature in subjects 30 years of age or older. Its absence, in the presence of an increased signal intensity within the disk, suggests a pathological process with a long T2 value, such as inflammation.

Adolescent↗
PubMed1985

Vertebral osteomyelitis: assessment using MR.

Thirty-seven patients who were clinically suspected of having vertebral osteomyelitis were prospectively evaluated with magnetic resonance (MR), radiography, and radionuclide studies. These findings were correlated with the final clinical, microbiologic, or histologic diagnoses. Based on the results of these latter studies, 23 patients were believed to have osteomyelitis. MR examinations consisted of at least a sagittal image (TE = 30 msec, TR = 0.5 sec) and an image obtained at TE = 120 msec, TR = 2-3 sec. All patients underwent radiographic and MR examinations, 36 underwent technetium 99m-HDP bone scanning, and 20 patients underwent gallium 67 scanning. Nineteen patients underwent both bone and gallium scanning. The imaging studies were reviewed independently by investigators blinded to the final diagnoses. MR had a sensitivity of 96%, specificity of 92%, and accuracy of 94%. Combined gallium and bone scan studies (19 cases) had a sensitivity of 90%, specificity of 100%, and accuracy of 94%. Bone scans alone had a sensitivity of 90%, specificity of 78%, and accuracy of 86%. Plain radiographs had a sensitivity of 82%, specificity of 57%, and accuracy of 73%. The MR appearance of vertebral osteomyelitis in this study was characteristic, and MR was as accurate and sensitive as radionuclide scanning in the detection of osteomyelitis.

Adult↗
PubMed1985

Magnetic resonance with marked T2-weighted images: improved demonstration of brain lesions, tumor, and edema.

The object of this study was to determine the sensitivity of magnetic resonance (MR) for imaging intracranial lesions with heavily T2-weighted images compared with that of computed tomographic (CT) and T1-weighted images. Fifty-five patients with known intracranial pathology consisting of primary neurogenic tumors, brain infarcts, demyelinating disease, and metastases were studied by MR and CT. Patients were studied with either 0.6 or 1.5 T systems with T1- and T2-weighted radiofrequency pulse sequences. The heavily T2-weighted images were found to be superior to the T1-weighted images in terms of sensitivity, with 168 lesions found versus 86 by CT and 104 by T1-weighted imaging.

Brain Edema↗
PubMed1985

Magnetic resonance imaging of the spine: applications and limitations.

MRI is a unique, noninvasive imaging modality that has already received wide application in the evaluation of abnormalities involving the spinal axis. It is the procedure of choice in the evaluation of suspected syringomyelia, Chiari malformation, and disk space infection. MRI is the only imaging modality presently capable of imaging multiple sclerosis plaques involving the spinal cord and is the only noninvasive modality that can diagnose nonherniated degenerated disks. MRI may provide valuable information in degenerative diseases of the spine, tumors of the spinal axis, and other congenital abnormalities, as either a primary or adjuvant imaging modality. Further investigation is needed to define the role of MRI in the evaluation of the traumatized and postoperative spine. Surface coil techniques hold promise in alleviating the present shortcomings of MRI, which are related primarily to slice thickness and attendant partial volume averaging. Chemical shift imaging may also be useful in accentuating subtle contrast differences between tissues and therefore highlighting abnormalities.

Arnold-Chiari Malformation↗
PubMed1984

Magnetic resonance. Principles and applications.

Magnetic resonance is a unique, noninvasive imaging modality which allows direct, multiplanar imaging and the possibility of obtaining biochemical information in vivo. Presently, MR appears most applicable to the evaluation of central nervous system abnormalities. The high sensitivity of MR in the evaluation of intracranial pathology suggests that it may eventually replace CT for many suspected diseases, if future investigations are able to improve its specificity. As previously noted, MR may be more diagnostic than other radiologic studies in the evaluation of suspected Chiari malformation, syringomyelia, congenital abnormalities, tumors of the spinal axis, and disc space infection. In the chest, MR appears to be more accurate than CT in the determination of the extent of mediastinal tumor, but at present cannot replace CT because of the lack of experience in imaging parenchymal nodules and benign diseases. MR of the breast is promising, but the size of the lesion may prove to be a limiting factor with magnetic field strengths commonly being utilized. There are inherent difficulties in the evaluation of cardiac disease with MR, but it offers a noninvasive method of investigating congenital heart disease and may provide valuable information in suspected myocardial ischemia and altered cardiac function. MR provides a new method of evaluating the vascular system, both in terms of providing anatomic information on large and medium-sized vessels and flow analysis. In the abdomen, MR appears to be most sensitive in the evaluation of suspected hepatic masses, but as with the brain, greater specificity will be needed to replace CT. At the present time, MR offers no distinct advantage over conventional imaging modalities in the evaluation of pancreatic disease, it maybe more accurate than CT in the staging of renal cell carcinoma. Larger studies are needed to determine the role of MR in the investigation of retroperitoneal adenopathy and adrenal abnormalities. In the pelvis, MR offers the hope of earlier diagnosis of prostatic carcinoma and may replace CT for staging of prostatic carcinoma and transitional cell carcinoma of the bladder. Limited MR experience with benign disease of the female pelvis suggests that it is currently more accurately evaluated with ultrasound. MR appears to be highly sensitive and specific for the diagnosis of avascular necrosis and may provide an early clue in suspected osteomyelitis. Finally, in vivo MR spectroscopy may provide unique metabolic information that was unobtainable prior to the advent of magnetic resonance, if this proves to be technically feasible.

Bone Diseases↗
PubMed1984

Digital subtraction angiography of the thoracic aorta.

Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

Adolescent↗
PubMed1984

Magnetic resonance imaging of intervertebral disk disease. Clinical and pulse sequence considerations.

Sixty-five patients were examined with magnetic resonance imaging (MR) to determine what combination of operator-selectable controls would result in a thorough examination of the intervertebral disks. There were 20 normal subjects, 8 with degenerative lumbar disk disease, 27 with both degeneration and herniation, 5 with stenosis of the spinal canal, and 5 with disk space infection. T2 was significantly longer in the normal nucleus pulposus than in the degenerated disk. Based on plots of in vivo signal intensity vs. repetition time (TR) for various echo times (TE), a sagittal 30-msec. TE and a 0.25-sec. TR were used for anatomical delineation and rapid localization, while sagittal and/or axial 120-msec. TE/3-sec. TR images were used to evaluate the cerebrospinal fluid and disk. Comparison with radiographs, high-resolution CT scans, and myelograms showed that MR was the most sensitive for identification of degeneration and disk space infection, separating the normal nucleus pulposus from the annulus and degenerated disk. Herniation, stenosis of the canal, and scarring can be identified as accurately with MR as with CT or myelography.

Adult↗
PubMed1984

The role of digital subtraction angiography in diagnosis of skull-base lesions.

Advances in radiographic diagnosis of skull-base lesions have made it possible to approach lesions formerly considered unresectable. The most important of these are the high-resolution computerized tomographic (CT) scanners with bone algorithms. In conjunction with their evaluations it is important to know in detail the vascular structures involved with the skull base. These include not only the jugular vein and bulb and lateral sinus associated with glomus tumor surgery but often the carotid artery associated with lesions of the jugular foramen and petrous apex. Conventional arteriograms have been the best way to evaluate the vascular system but were occasionally associated with some risk and much patient discomfort. New digital subtraction techniques (digital subtraction angiography [DSA] using an intravenous bolus injection of dye) are now yielding x-ray studies equal to or better than conventional arteriography. DSA will be described and the results of these studies of various lesions of the skull base will be presented in conjunction with the results of high-resolution CT scanning to show the complete workup of the skull-base lesion possible for an outpatient.

Aged↗
PubMed1984

Nuclear magnetic resonance of the spine: clinical potential and limitation.

Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluated. It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin-echo technique with appropriate T1 and T2-weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography.

Arteriovenous Malformations↗
PubMed1983

Digital subtraction angiography in the evaluation of intracranial and extracranial vascular disease.

Digital subtraction angiography (DSA) is a method of visualizing the vessels of the body with the intravenous injection of contrast material. Improvements in computers, television systems, and image intensifiers have contributed to the increased image quality of DSA. With DSA, the vessels such as the carotid bifurcations and the intracranial vasculature can be visualized with a 2-3% concentration of contrast material, while with conventional angiography, the concentration of contrast in vessels is 40-50%. Using IV DSA, visualization of the carotid bifurcations is of good or excellent quality 85% of the time. In a high percentage of these cases, IV DSA replaces conventional angiography, although for imaging of the intracranial vessels, IV DSA is not as good as conventional angiography. In most tumor patients, however, conventional intracranial angiography is not needed because IV DSA combined with computed tomography gives sufficient information.

Angiography↗