Search PubMed⌕ Search

Biomedical subjects

M L Schiebler

Publications and source records attributed to M L Schiebler.

At least 37 records · Page 2Linked to original sources
PubMed1991

In vivo and ex vivo magnetic resonance imaging evaluation of early disc degeneration with histopathologic correlation.

The in vivo and ex vivo microanatomic appearance of early disc degeneration were identified by magnetic resonance imaging and correlated with their respective histopathologic findings. Five cadaver spines (18 discs) and 25 patient studies (122 discs) all imaged at 1.5 Tesla were studied. Two signs of early degenerative disc disease were found: infolding and the central dot. Infolding of the central fibers of the outer annulus coalesced into a central dot of low signal intensity that was seen on both the ex vivo and in vivo images. Infolding was seen 29 of 122 times, and the central dot was observed 15 to 122 times on the in vivo images. A later form of degenerative disc disease was identified as a separation of the nucleus pulposus from the hyaline cartilage end-plate. This separation was seen as a linear area of either low or high signal intensity on the ex vivo images but only as a band of high signal intensity on the in vivo spin-echo 2,500-msec/80-msec images. Only 7 of 122 in vivo discs showed this separation. Internal herniation of nucleus pulposus into the outer annulus was seen only on the ex vivo images. Early degenerative disc disease may exist before there is loss of disc height or signal intensity on the long time-to-repetition (TR)/time-to-echo (TE) magnetic resonance images.

Adult↗
PubMed1991

Normal and degenerated intervertebral disk: in vivo and in vitro MR imaging with histopathologic correlation.

The components of the intervertebral disk serve two purposes. The hydrophilic matrix is contained by circumferential rings of fibrocartilage (outer anulus) and Sharpey's fibers. The gellike hydrophilic matrix acts as a cushion between the vertebral body endplates by providing an even distribution of axial and rotational compressive forces. The construction and integrity of the intervertebral disk are assessed well by MR. The purpose of this pictorial essay is to show the in vitro and in vivo MR appearances of the normal and degenerated disk, and to correlate these MR changes with their respective histopathologic findings.

Humans↗
PubMed1991

Normal anatomy of the thoracic inlet as seen on transaxial MR images.

The thoracic inlet can now be studied with high-resolution MR imaging. Recent advances in fold-over suppression (antialiasing software) allow for small fields of view without the usual problems of aliasing from the shoulders. This pictorial assay shows the normal anatomy that can be seen in this area on transaxial MR images. The vagus, phrenic, and recurrent laryngeal nerves can be seen as discrete entities. MR imaging can be used more often for pathologic conditions involving the lower portion of the neck and the thoracic inlet.

Brachiocephalic Trunk↗
PubMed1990

Computed tomography of hepatic venous hypertension: the reticulated-mosaic pattern.

A reticulated-mosaic pattern of the liver was identified on contrast-enhanced computed tomography in 4 of 20 patients with constrictive pericarditis or congestive heart failure. Reflux of contrast into a distended inferior vena cava and the hepatic veins was identified in 3 of the 4 patients. This abnormal enhancement pattern combined with hepatic venous or caval reflux of contrast indicates the presence of hepatic venous hypertension, and should not be mistaken for other abnormalities that may result in inhomogeneous hepatic enhancement.

Adult↗
PubMed1990

Pulmonary vascular cine MR imaging: a noninvasive approach to dynamic imaging of the pulmonary circulation.

Cine gradient-recalled magnetic resonance (MR) imaging, which has flow sensitivity and high temporal resolution, may potentially yield both morphologic and dynamic flow-related information in the pulmonary vasculature. The authors used this modality to evaluate pulmonary vessels in 12 healthy subjects and in 14 patients with a variety of cardiopulmonary disorders. Normal pulmonary arteries and veins were characterized by distinctive signal intensity and diameter variations as well as motion of the vessels during the cardiac cycle. Patients with pulmonary arterial hypertension demonstrated loss of the normal pulsatile systolic increase and diastolic decline in velocity-related signal intensity and in diameter of the proximal pulmonary arteries. Disorders of pulmonary venous signal and diameter profiles during the cardiac cycle, which show a characteristic biphasic pattern in healthy subjects, were identified in five patients with mitral valvular disease. These initial results indicate that cine MR imaging techniques hold promise in the evaluation of pathophysiologic conditions in the pulmonary circulation.

Adult↗
PubMed1990

MRI of Askin's tumor. Case report at 1.5 T.

This represents the first case of an Askin's tumor demonstrated on MRI. It showed a large pleural-based mass which trapped pleural fluid in large pseudotumors. The disease was unilateral and involved the mediastinum as well. Magnetic resonance imaging was helpful in demonstrating extrathoracic disease in the area of the right brachial plexus.

Adult↗
PubMed1989

Isthmic spondylolysis of the lumbar spine: MR imaging at 1.5 T.

The appearance on magnetic resonance (MR) images of the normal pars interarticularis in 13 patients was reviewed and contrasted with that of the pars in eight patients with spondylolysis. The pars defect usually had an intermediate signal intensity with all pulse sequences; however, this intensity was somewhat variable depending on the exact ratio of cartilage, fat, and fluid within each bone defect. The pars defect was best seen with spin-echo 600/20 (repetition time msec/echo time msec) images. In three cases, out-of-phase images showed the spondylolysis best, because of extension of fat to the borders of the defect. The sagittal view allowed one to separate spondylolysis from the joint space of posterior facets since the orientation of the defects is perpendicular to the facets; thus, a common pitfall encountered with cross-sectional axial imaging techniques is avoided. MR imaging poorly delineated bone fragments around the defect, which may produce nerve root impingement, but revealed other numerous complications that occur with spondylolysis, including spondylolisthesis and herniation of the disk above.

Adult↗
PubMed1989

Prostatic carcinoma and benign prostatic hyperplasia: correlation of high-resolution MR and histopathologic findings.

High-resolution magnetic resonance (MR) imaging of 24 fresh radical prostatectomy specimens was performed on an experimental 1.9-T system. Direct correlation between the findings in 7-micron-thick macrosections and their corresponding MR images was possible. Fourteen patients had macroscopic evidence of cancer. In all 14 cases, the carcinoma nodules appeared as areas of low signal intensity on images obtained with a repetition time of 2,500 msec and an echo time of 80 msec. Ten of 14 nodules had well-defined margins and consisted of densely packed glandular elements, which displaced the surrounding normal glandular material of higher signal intensity. Ten specimens displayed benign prostatic hyperplasia (BPH). The MR characteristics of this entity were quite variable but relatively predictable, depending on the distribution and size of the glandular elements, as well as the composition of the surrounding stroma. In BPH, the changes began in the central portion of the gland. The areas of highest signal intensity corresponded to dilated glandular elements (cystic ectasia), while the areas of lowest signal intensity corresponded to collagen (scar) and fibromuscular stroma. Nodules of mixed glandular BPH and fibromuscular BPH were found to have signal intensities similar to those of well-differentiated nodules of prostatic adenocarcinoma.

Aged↗
PubMed1988

Spondyloarthropathy of the cervical spine in long-term hemodialysis.

Changes stimulating osteomyelitis have recently been described in patients undergoing long-term hemodialysis. These consist of disk-space narrowing and irregularity of adjacent end plates. However, the characteristic prevertebral mass and clinical evidence of infection are often absent. In the appropriate clinical situation, although plain radiography and computed tomography have been helpful, magnetic resonance imaging may be more definitive in excluding infection and may obviate biopsy. The authors' imaging experience with five patients with this entity forms the basis of this report.

Aged↗
PubMed1988

Hyaline cartilage-origin bone and soft-tissue neoplasms: MR appearance and histologic correlation.

Magnetic resonance (MR) images and histologic studies of 16 chondroid-matrix lesions were reviewed to determine if any distinctive morphologic or signal features might be discerned. Ten biopsy-proved nonchondroid bone lesions were compared in terms of configuration and signal characteristics. The tumor matrix had a distinctive appearance of homogeneous high signal intensity in a defined lobular configuration on images of all hyaline cartilage lesions obtained with a long repetition time and a long echo time. The areas of hyperintensity relative to muscle corresponded to areas of hyaline cartilage matrix with its uniform composition, low cellularity, and high water content; the lobular morphologic characteristic had an identical histologic correlate. The chondroblastomas, clear-cell chondrosarcoma, and synovial chondromatosis demonstrated a much more cellular stroma, with only scattered islands of chondroid matrix, and were isointense or hypointense compared with muscle on all MR sequences. The distinctive lobular, high-intensity MR appearance was not seen in the ten nonchondroid bone lesions.

Adolescent↗
PubMed1988

Avascular necrosis versus other diseases of the hip: sensitivity of MR imaging.

Magnetic resonance (MR) imaging of the hip has been useful in the examination of patients for the presence of avascular necrosis (AVN). In the detection of AVN, MR imaging is more sensitive than computed tomography or nuclear scintigraphy. This study assessed the usefulness of MR imaging in the differentiation of AVN from other hip diseases. Twenty-two cases of non-AVN hip disease were matched with 23 biopsy-proved cases of AVN and ten normal controls. MR images were rated in a blinded manner by five experienced radiologists, and receiver operating characteristic (ROC) analysis was performed on the data. In the discrimination of AVN from other hip diseases or from normality, the A(z) value (the area under the ROC curve) was 98.6. With a specificity of 98%, MR imaging was 97% sensitive in the differentiation of AVN from normality, 85% sensitive in the differentiation of AVN from non-AVN disease, and 91% sensitive in the differentiation of AVN from both conditions. MR imaging may therefore help discriminate between AVN and other hip diseases.

Diagnosis, Differential↗
PubMed1988

Prostatic carcinoma: staging with MR imaging at 1.5 T.

Magnetic resonance (MR) imaging was used to stage prostatic carcinoma in 81 patients with a proved diagnosis. MR imaging findings were correlated with histologic findings regarding the local extent of disease (37 patieNts) and the presence of nodal metastases (51 patients). Tumor nodules were detected in the peripheral zone (PZ) in 34 of 37 patients and were of low signal intensity compared with the signal of the PZ. Hemorrhage in the PZ represented a problem in tumor detection and in tumor volume measurement. When multiple criteria for local tumor spread were combined, MR imaging had a sensitivity of 72%, a specificity of 84%, and an accuracy of 78% in the differentiation of stage A or B from Stage C or D disease. Assessment of seminal vesicle invasion was more accurate than assessment of direct extracapsular spread. In five patients, microscopic invasion of the capsule (stage C) was classified as stage B with MR imaging; from a clinical standpoint, this should not affect patient treatment and prognosis. The MR imaging sensitivity in the detection of lymph node metastases was 69%, with a specificity of 95% and an accuracy of 88%. In this study MR imaging proved reliable in the comprehensive evaluation and staging of prostatic carcinoma.

Aged↗
PubMed1988

Meniscal and ganglion cysts of the knee: MR evaluation.

Meniscal and ganglion cysts frequently present as palpable masses of the knee but occur at different locations than do popliteal cysts. Meniscal cysts also may be discovered incidentally on studies performed for suspected internal derangement. Sixteen cystic lesions of the knee were evaluated with MR, including 11 meniscal cysts and five ganglion cysts. Scans were performed at 1.5 T by using a transmit/receive extremity coil or a receive-only surface coil. Standard spin-echo imaging, including at least one long-TR/asymmetric-TE sequence, was performed in all cases. In six patients, gradient-echo, reduced flip-angle sequences also were done. All meniscal cysts (but none of the ganglion cysts) were associated with horizontal meniscal tears. Cysts were visualized best on the long-TR/TE images; meniscal tears were seen best on the short-TR/TE and long-TR/short-TE images. Meniscal tears and cysts were also seen well on the fast-scanning sequences. Septations were noted in four meniscal cysts and in four ganglion cysts on the long-TR/TE images. Long-TR/TE images were also useful in showing the relationship between the cyst and joint capsule in three of the ganglion cysts. MR imaging is an effective, noninvasive method for evaluating cystic lesions of the knee. Meniscal cysts are always associated with underlying horizontal meniscal tears, which can be detected with MR. Ganglion cysts are not associated with meniscal tears, but may have connections to the joint capsule, which can be detected with MR.

Humans↗
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

Strategies for musculoskeletal magnetic resonance imaging.

There is a broad range of clinical applications for MRI in the diagnosis of musculoskeletal disease, and the emphasis in this article is on the evaluation of the joints and extremities. A discussion of basic principles, including radiofrequency coils, positioning, pulsing sequences, imaging planes, and technical parameters is followed by discussions of tailored approaches to the evaluation of mass lesions and joint pathology for specific regions of the musculoskeletal system. In the final section, consideration is given to the overall role of MRI in the diagnosis of musculoskeletal disorders with respect to other established imaging modalities.

Bone Cysts↗
PubMed1987

The magnetic resonance imaging appearance at 1.5 tesla of cartilaginous tumors involving the epiphysis.

Three cases of lytic, calcified epiphyseal lesions with plain film and computed tomography features suggestive of chondroblastoma were imaged by magnetic resonance imaging. Histopathologic correlation was obtained in each case. Two cases of chondroblastoma showed low signal intensity on both short (TR600/TE20ms) and long (TR2500/TE80ms) spin echo (SE) images. The third case, a clear cell chondrosarcoma, demonstrated increased signal intensity on moderately T2 weighted (TR2500/TE40ms) images. These findings suggest that magnetic resonance imaging may be helpful in distinguishing these lesions.

Adolescent↗