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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 91 records · Page 5Linked to original sources
PubMed1998

Magnetic resonance imaging of knee cartilage repair.

Cartilage injury resulting in osteoarthritis is a frequent cause of disability in young people. Osteoarthritis, based on either cartilage injury or degeneration, is a leading cause of disability in the United States. Over the last several decades, much progress has been made in understanding cartilage injury and repair. Magnetic resonance (MR) imaging, with its unique ability to noninvasively image and characterize soft tissue, has shown promise in assessment of cartilage integrity. In addition to standard MR imaging methods, MR imaging contrast mechanisms under development may reveal detailed information regarding the physiology and morphology of cartilage. MR imaging will play a crucial role in assessing the success or failure of therapies for cartilage injury and degeneration.

Cartilage, Articular↗
PubMed1997

Paraplegia due to ossification of ligamenta flava in X-linked hypophosphatemia. A case report.

STUDY DESIGN: Spinal canal decompression at the most prominent of multiple posterior calcified thoracic lesions in a case of X-linked hypophosphatemia was undertaken for treatment and diagnosis purposes, as well as to assess possible nature of the pathophysiology underlying the presenting deficits. OBJECTIVES: To discuss the clinical assessment diagnostic and treatment aspects of this rare coincidence of ossification of ligamenta flava in the patient with the skeletal deformities of X-linked hypophosphatemia. SUMMARY OF BACKGROUND DATA: The patient with the stigmata and chemical findings of an X-linked hypophosphatemia presented with paraplegia and multiple calcified posterior spinal thoracic lesions. This was studied with magnetic resonance imaging and electrophysiologic studies of the spinal sensory pathways of the legs. These data constituted the preoperative information required to assess later results of surgical intervention. METHODS: Presurgical clinical, imaging and electrophysiologic studies and laboratory and pathologic investigations of the surgical specimens. RESULTS: Resolution of the paraplegia with walking and return to work in a physically demanding job for the last 4 or 5 years of postoperative follow-up after surgical decompression of the spinal cord only at the worst and highest of the effected spinal levels. CONCLUSION: The coincidence of X-linked hypophosphatemia and ossification of ligamenta flava has been reported only in two or three cases in the literature. Removal of the offending ossifying lesion is known to result in resolution of the clinical deficits but similar lesions at other spinal levels are suspected of producing recurrences. The return of function and of the corresponding electrophysiologic correlates indicate a neurono-apractic nature of the neurologic symptoms.

Bone and Bones↗
PubMed1997

Gorham syndrome of the thorax and cervical spine: CT and MRI findings.

Gorham syndrome is a rare disorder that is characterized by local osseous invasion and surrounding soft tissues by an angiomatous mass, eventually causing lysis of the affected bone. To date, only four cases have reported the MR imaging appearance of this disease and the findings have been variable. We present a case involving the cervical and thoracic spine and part of the osseous hemithorax with attention to the MR findings.

Angiomatosis↗
PubMed1997

Ischemic necrosis of the entire femoral head and rapidly destructive hip disease: potential causative relationship.

OBJECTIVE: Rapidly destructive hip disease (RDHD) is an uncommon disorder of the hip that has been considered a disease of unknown cause and distinct from ischemic necrosis of the femoral head. The objective of this study was to investigate ischemic necrosis of the femoral head as one potential cause of RDHD. DESIGN AND PATIENTS: In 600 patients who underwent MR imaging of the hip, 20 cases of ischemic necrosis involving the entire femoral head in 18 patients (3%) were retrospectively studied with routine radiography and MR imaging. All patients had surgically confirmed ischemic necrosis of the femoral head. RESULTS AND CONCLUSIONS: All patients showed rapid destruction of the femoral head on routine radiography and MR imaging as compared with the gradual onset of clinical symptoms. Plain radiographs showed several bone fragments at the inferomedial aspect of the femoral head (75%), acetabular erosions (55%), eccentric depression at the lateral articular surface of the femoral head conforming to the adjacent acetabulum (35%), and mild osteoarthritis (15%). Bone sclerosis was often present at sites of impaction between the femoral head and the acetabulum. MR imaging showed marked distention of the joint capsule in all cases. In 14 of 20 cases, the contents of the joint space showed predominantly low or intermediate signal intensity on T1- and T2-weighted images. Ischemic necrosis involving the entire femoral head may represent one of the causes of RDHD.

Adult↗
PubMed1997

Fibrolipomatous hamartoma: MR imaging findings.

OBJECTIVE: To analyze the MR imaging features of fibrolipomatous hamartoma (FLH) of nerves. DESIGN AND PATIENTS: MR imaging studies from six patients (three men and three women) were retrospectively reviewed by three musculoskeletal radiologists. In four patients, a biopsy of the nerve lesion was performed. In two patients, biopsy data were unavailable and the diagnosis was based on the clinical history combined with the MR imaging findings. RESULTS AND CONCLUSION: MR imaging demonstrated fusiform nerve enlargement that was caused by fatty proliferation and thickening of nerve bundles. Nerve bundles appeared as serpentine tubular structures, hypointense on both T1- and T2-weighted images. The degree of fatty proliferation varied among patients. In addition, significant variation in the distribution of fat along the course of the nerves was noted. In three patients, FLH followed the branching pattern of the nerves, a characteristic pathologic finding. In two patients, intramuscular fat deposition (biceps and tibialis posterior muscles) was present. MR imaging findings of FLH are typical, allowing a confident diagnosis. The variation of fatty proliferation among patients and involved nerves as well as the tendency of the abnormalities to follow the branching pattern of the nerves is well demonstrated with MR imaging. FLH may present as an isolated nerve lesion, may be associated with intramuscular fat deposition, or may occur as a feature of macrodystrophia lipomatosa (MDL).

Adult↗
PubMed1997

Hemophilic pseudotumor: spectrum of MR findings.

OBJECTIVE: To determine the MR imaging appearance of hemophilic pseudotumor (HP) and its clinical implications. DESIGN AND PATIENTS: Five hemophilic patients (aged 35-77 years) with 12 HPs in various anatomic locations were included in this study. The MR images were retrospectively evaluated for the appearance of the lesions and accompanying abnormalities, as well as their clinical implications. RESULTS AND CONCLUSION: MR images of all five patients (12 lesions) showed well-defined masses containing blood clots in various stages of organization surrounded by a fibrous capsule in subcutaneous fat or in intramuscular, interfascial, subperiosteal, and intraosseous locations. Intramuscular HP frequently had mural nodules. This is an almost unique appearance that is somewhat unexpected. MR imaging allowed determination of number, size, and extent of the lesions, evidence of neurovascular involvement, and accompanying musculoskeletal alterations. It is concluded that MR imaging not only is a sensitive and accurate method for detecting and diagnosing HP and providing useful information for therapeutic decision making, but can also be used to assess results of treatment by allowing evaluation of the evolution of blood products, the size of lesions in regions difficult to access by physical examination, and recurrent bleeding within a chronic lesion.

Adult↗
PubMed1997

Dynamic MR imaging of carpal tunnel syndrome.

OBJECTIVE: To evaluate the diagnostic value of the MR imaging syndrome before and after performance of provocative exercises in patients with dynamic carpal tunnel syndrome. DESIGN: Fat-suppressed proton-density and T2-weighted spin-echo images of the wrist were obtained prior to and after provocative, standardized exercises. Images were interpreted in masked fashion with regard to six MR criteria of carpal tunnel syndrome: (a) bowing of the transverse ligament, (b) and (c) deformation of the median nerve at the pisiform and hamate levels respectively, (d) signal abnormality of the median nerve, (e) presence of fluid in the wrist joints and/or carpal tunnel, and (f) presence of synovial swelling. PATIENTS: Twenty-one wrists in 20 patients with subjective complaints of carpal tunnel syndrome and equivocal or negative clinical findings and negative electrodiagnostic examinations were included (age range 21-61 years, mean 37 years, 2 men and 18 women). The diagnosis of dynamic carpal tunnel syndrome was made and confirmed by surgery in 18 of the 21 symptomatic wrists. The control group consisted of 15 asymptomatic wrists in volunteers (age range 22-60 years, mean 35 years, 8 men and 7 women). RESULTS AND CONCLUSIONS: Sensitivities and specificities of the six MR criteria were 90.5-100%, and 6.7-86.7%, respectively, both before and after exercise. Likelihood ratios proved statistically significant differences between the symptomatic and asymptomatic wrists (P < 0.0001-0.0002) for the prevalence of all MR criteria with the exception of fluid within the carpal joints and/or carpal tunnel. Changes of the MR appearance after exercise had a low sensitivity (4.8-71.4%) but high specificity (86.7-100%) for dynamic carpal tunnel syndrome. In conclusion, MR imaging contributes to the diagnosis of carpal tunnel syndrome when clinical signs are confusing and electrodiagnostic studies are negative. Dynamic examinations improve specificity of MR imaging for such diagnosis.

Adult↗
PubMed1997

Evolving stages of lipohemarthrosis of the knee. Sequential magnetic resonance imaging findings in cadavers with clinical correlation.

RATIONALE AND OBJECTIVES: Lipohemarthrosis, the presence of fat and blood in a joint cavity, exhibits several complex layers related to differences in specific component relaxation on magnetic resonance (MR) images. The authors investigated sequential changes in the appearance of lipohemarthrosis of the knee as demonstrated by MR imaging. METHODS: Sequential MR imaging over a 4-day period was performed on two cadaveric knees after intraarticular injection of blood from a volunteer and fat from a cadaveric tibia (50 mL of blood and 25 mL of fat in one knee and 15 mL of blood and 5 mL of fat in the other knee). The authors determined components in the joint based on MR signal behavior. Magnetic resonance imaging examinations of four patients with intracapsular fractures and lipohemarthroses of the knee were reviewed retrospectively. RESULTS: Sequential MR images of cadaveric knees showed serial changes representing progressive formation and lysis of blood clot. Several fluid-fluid levels (globules of fat at the interface between fat and blood) and entrapment of fat were early findings of lipohemarthrosis. Three different fluid levels appeared approximately 3 hours after injection of fresh blood and marrow fat. The 96-hour study demonstrated three distinct levels. CONCLUSIONS: Lipohemarthrosis demonstrates temporal changes on MR imaging related to stages of formation and lysis of blood clot.

Adult↗
PubMed1997

Cupid's bow contour of the vertebral body: evaluation of pathogenesis with bone densitometry and imaging-histopathologic correlation.

PURPOSE: To investigate the Cupid's bow contour by means of bone densitometry and imaging-histopathologic correlation. MATERIALS AND METHODS: Radiographs and histologic slices were obtained in 64 cadaveric thoracolumbar spines to assess the morphology, distribution, and histopathologic features of the Cupid's bow contour. Dual-energy x-ray absorptiometry and radiography were performed in the lumbar spine in 406 healthy subjects. Bone density and body height and weight were then related to the presence of the Cupid's bow contour. The Cupid's bow contour was compared with the fish vertebra of osteoporosis and Schmorl node. RESULTS: No clinically important relationship was found between lumbar bone density, body height and weight, and prevalence of the Cupid's bow contour. Histologic examination showed thickened bone in the Cupid's bow end plate with annular fibers inserting into this region. In cadavers, the Cupid's bow contour occurred at multiple lumbar and thoracic levels, with the highest frequency in the lower lumbar spine. Lateral radiographs enabled better detection of the contour change. CONCLUSION: The Cupid's bow deformity is a developmental phenomenon that is unrelated to osteopenia or mechanical stress on the spine.

Absorptiometry, Photon↗
PubMed1997

Intraosseous venous drainage anomaly in patients with pretibial varices: imaging findings.

PURPOSE: To determine a set of distinctive imaging findings seen in symptomatic patients with pretibial varices. MATERIALS AND METHODS: Medical records and imaging studies of patients who presented with pretibial varices over an 8-year period were collected from four institutions. Findings in six symptomatic patients with pretibial varices were retrospectively reviewed. Radiographic and magnetic resonance (MR) imaging findings were available from all six patients; findings from several other modalities were also available in some patients. RESULTS: Conventional radiographs showed a small osteolytic defect in the anterior cortex of the midtibia and a prominent, longitudinally oriented, radiolucent groove in the proximal half of the tibial diaphysis. MR images showed pretibial varices connected to an enlarged vessel in the tibia that eventually exited through the nutrient foramen. Computed tomographic (three patients), sonographic (four patients), venographic (four patients), arteriographic (two patients), and surgical (three patients) findings demonstrated that these patients had an unusual intraosseous varix that traversed the anterior cortex, medullary cavity, and posterior cortex of the tibia. CONCLUSION: Recognition of these findings can prevent misdiagnosis and may prove helpful in the planning of appropriate treatment.

Adolescent↗
PubMed1997

Short echo time projection reconstruction MR imaging of cartilage: comparison with fat-suppressed spoiled GRASS and magnetization transfer contrast MR imaging.

PURPOSE: To evaluate short echo time (TE) projection reconstruction magnetic resonance (MR) imaging in the detection of cartilage lesions. MATERIALS AND METHODS: Twenty-seven cartilage regions of 10 human patellar specimens were examined with the following MR sequences: short TE projection reconstruction (repetition time msec/TE msec, 400/0.15), fat-suppressed three-dimensional spoiled gradient-recalled acquisition in the steady state (Spoiled GRASS) (50/10, 60 degrees flip angle), and magnetization transfer contrast (MTC) subtraction (400/6). MR findings were correlated with histopathologic grading of the cartilage. RESULTS: For detection of cartilage lesions, sensitivity of projection reconstruction imaging (100%) was significantly greater (P = .03) than that of MTC (62%) but not significantly greater (P > .05) than that of Spoiled GRASS (81%) imaging. Accuracy of projection reconstruction was significantly greater than that of MTC (P = .004) and Spoiled GRASS (P = .03) imaging. Unmasking of collagen fibers was most predictive of abnormal signal intensity of the cartilage with all sequences. CONCLUSION: In vitro, short TE projection reconstruction MR imaging provides superior delineation of cartilage lesions when compared with two other sequences. On Spoiled GRASS and MTC images, signal intensity of the superficial layer of cartilage is not a reliable sign for surface integrity.

Aged↗
PubMed1997

Collateral ligaments of the elbow: conventional MR imaging and MR arthrography with coronal oblique plane and elbow flexion.

PURPOSE: To determine the best plane and position of the elbow for optimal visualization of normal and abnormal collateral ligaments with conventional magnetic resonance (MR) imaging and MR arthrography, to determine the normal appearance of the collateral ligaments at MR arthrography and to assess use of MR arthrography in evaluation of collateral ligamentous lesions. MATERIALS AND METHODS: Nine cadaveric elbow specimens were imaged with and without intraarticular administration of gadolinium-containing solution in several planes that were identified as potentially useful in a pilot study in two specimens. MR imaging findings were compared with anatomic findings. RESULTS: Normal and abnormal ligaments were best depicted in a 20 degrees posterior oblique coronal plane in relation to the humeral shaft with the elbows extended and a coronal plane aligned with the humeral shaft with the elbows slightly flexed (20 degrees-30 degrees of flexion). Gadolinium enhancement improved the delineation of normal and abnormal ligaments on T1-weighted images in each case. CONCLUSION: The posterior oblique coronal plane with the elbows extended or the coronal plane aligned with the humeral shaft with the elbows slightly flexed allows accurate assessment of the collateral ligaments. Gadolinium-enhanced MR arthrography of the elbow seems to be a promising technique.

Aged↗
PubMed1997

Extensive intraosseous gas associated with lymphangiomatosis of bone: report of three cases.

Asymptomatic pneumatosis may be found in patients with lymphangiomatosis of bone. The authors report three cases from three institutions in which development of intraosseous gas in association with lymphangiomatosis of bone was found incidentally at imaging. Soft-tissue emphysema also developed in two cases. In all three cases, intraosseous gas developed after biopsy or surgery in the areas involved with lymphangiomatosis.

Adolescent↗
PubMed1997

Symptomatic herniation pits of the femoral neck: anatomic and clinical study.

OBJECTIVE: The purpose of this study was to investigate the pathogenesis of herniation pits of the femoral neck, which are frequently considered a normal variant, and to describe the imaging abnormalities of such pits in three symptomatic patients. CONCLUSION: The changing relationship between the joint capsule and the iliopsoas muscle appears to be important in the pathogenesis of the herniation pit, especially in athletic persons. In some cases, these pits may enlarge, the overlying cortex may fracture, and significant clinical manifestations may be apparent.

Adult↗
PubMed1997

MR imaging truncation artifacts can create a false laminar appearance in cartilage.

OBJECTIVE: The purpose of this study was to investigate the laminar appearance of cartilage on MR images. MATERIALS AND METHODS: Theoretical modeling of truncation artifacts was used to predict spatial patterns and associated intensity variations in MR imaging. A numerical simulation of a ring model was used to show truncation artifacts as a function of the angle in the image plane for unequal in-plane resolutions. MR imaging of 10 cadaveric human patellae at several resolutions used an imaging protocol that produced high-contrast images of cartilage. The high-resolution image of each MR imaging set was reduced in resolution by low-pass filtering and compared with the acquired images of equivalent resolution. Variable-resolution images of the patella of a healthy human volunteer were also acquired. RESULTS: Truncation artifacts from opposing cartilage edges can create false laminae and artifactual intensities. The resulting geometric variations can alter the apparent width of the cartilage as well. The intensity variations produced by truncation artifacts can be as much as 22% of the actual intensity. The most pronounced artifactual trilaminar appearance occurs when cartilage thickness exceeds the image resolution by a factor of 4. Truncation artifacts vary as a function of the angle in the imaging plane for unequal resolutions in the two directions. CONCLUSION: Truncation artifacts can produce an artifactual laminar appearance in cartilage and alter the apparent cartilage width.

Artifacts↗
PubMed1997

Normal patellar retinaculum: MR and sonographic imaging with cadaveric correlation.

OBJECTIVE: The purpose of our study was to define retinacular anatomy with MR imaging and sonography. MATERIALS AND METHODS: Five cadaveric knee specimens underwent sonography and MR imaging using the following sequences: T1-weighted axial, sagittal, coronal, and five oblique planes and axial three-dimensional gradient-echo imaging. Three knees were injected with gelatin gadolinium solution before imaging. All five specimens were sectioned. Correlation was made between findings derived from MR imaging, sonography, and cadaveric sections. RESULTS: T1-weighted axial images without intraarticular gadolinium were most useful for revealing the superficial layer and deep ligaments of the retinacula; however, the oblique sagittal and oblique coronal planes showed the deep ligaments more clearly in their craniocaudal dimensions. Sonography revealed the retinacula as bilaminar structures with discrete superficial and deep layers but failed to distinguish the deep ligaments from one another. CONCLUSION: Conventional T1-weighted axial MR images showed the various components of the retinacula including the medial patellofemoral ligament, which is an important stabilizing structure. Oblique imaging planes may be a helpful adjunct to axial imaging planes. Sonography can consistently identify the retinacula and may be useful in their assessment.

Aged↗
PubMed1997

Measurements of cortical thickness in experimentally created endosteal bone lesions: a comparison of radiography, CT, MR imaging, and anatomic sections.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of cortical measurements of experimentally created endosteal cortical lesions and to assess the sensitivity of radiography, CT, and MR imaging in the detection and measurement of such lesions. MATERIALS AND METHODS: Thirty-six cortical lesions were created in three fresh cadaveric femurs. After performing radiography, CT, and MR imaging, we sectioned the specimens in the axial plane. We then measured the remaining cortex at the lesions and the normal cortex adjacent to the lesions on all images and corresponding anatomic sections. The measurements of thickness of the cortex as seen with the different imaging methods and the anatomic sections were compared. Measurements were repeated to evaluate the influence of different window settings on the MR imaging measurements. RESULTS: When measured on radiographs, cortical thickness was overestimated in 58% of lesions. With CT, cortical thickness was overestimated by 0-15% in 94% of all lesions. With MR imaging, cortical thickness was uniformly underestimated by 3-17%. Measurements made on MR images varied according to different window settings. The proton density-weighted sequence yielded the highest sensitivity in the detection of shallow cortical lesions; the T1-weighted spin-echo sequence was the least sensitive of the MR sequences. CONCLUSION: In our cadaveric study, cortical thickness in the presence of endosteal lesions was overestimated on radiographs and CT scans and underestimated on MR images. Measurements derived from MR imaging are strongly influenced by the window setting. MR imaging with the proton density-weighted sequence is the most sensitive for detection of shallow cortical lesions and is more sensitive than CT.

Bone Neoplasms↗