Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 631 records · Page 35Linked to original sources

PubMedDate not supplied

Digital arthrography in the evaluation of painful joint prostheses.

Digital arthrography was accomplished in 16 patients who had painful prostheses. In each instance, resulting arthrographic abnormalities were compared with those apparent on subsequent overhead radiographs. Results indicate the potential value of the digital technique in this clinical setting. The examination is easy to perform and rapid, and allows the examiner to view the changing images in the subtraction mode. Image manipulation and enhancement are also possible.

Aged↗

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Acetabular alterations in untreated congenital dysplasia of the hip: computed tomography with multiplanar re-formation and three-dimensional analysis.

The alterations in acetabular morphology that occur in untreated congenital hip dysplasia (CDH) were evaluated in 29 prehistoric and four modern hemipelvis specimens using inspection, sectioning, conventional radiography, CT, and multiplanar re-formation with three-dimensional image reconstruction. Three major patterns of acetabular morphology were recognized, each reflecting a different grade of severity of dysplasia. Type I (positionally unstable or subluxatable) hips were characterized by acetabular deepening with prominent circumferential ossification within the transverse acetabular ligament and everted limbus. Type III (dislocated) hips demonstrated definite false acetabula separated from triangular remnants of the true acetabula by ossified inverted limbi. Type II (subluxated) hips revealed an intermediate pattern, with acetabular elongation and ossification of deformed limbi, but without definite pseudoacetabula. Computed tomography, particularly with three-dimensional analysis, was extremely useful in characterizing the abnormal acetabular morphology of untreated CDH. An awareness of the secondary osseous alterations of this disorder facilitates understanding the spectrum of hip instability and its soft tissue abnormalities.

Acetabulum↗

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CT analysis of proximal femoral trabecular pattern simulating skeletal pathology.

The proximal femoral trabecular pattern was studied in 20 patients, six cadavers, and 20 macerated specimens using plain film radiography and CT. A distinctive pattern of increased radiodensity in the proximal femur is described in patients and specimens with osteoporosis and osteoarthritis. The appearance is similar to that of an enchondroma or bone infarct. This pattern may be explained by biomechanical principles and is created by unmasking or hypertrophy of preexistent, reinforcing trabeculae. Confusion with osseous pathology can be avoided if the radiologist is aware of this pattern.

Bone Diseases↗

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Comparison of conventional and computed arthrotomography with MR imaging in the evaluation of the shoulder.

To compare conventional arthrography and computed arthrotomography (CAT) with magnetic resonance (MR) imaging in the evaluation of the shoulder, we studied 18 patients who underwent conventional double contrast arthrography and CAT, and T1-, balanced, and T2-weighted MR imaging. The arthrograms were independently reviewed by two of the authors and the MR images were independently reviewed by three other authors in a systematic fashion with the aid of a prewritten evaluation form. The findings were compared among reviewers and between imaging methods. We found MR comparable to conventional arthrography in the evaluation of the rotator cuff; however, MR also enabled evaluation of tendonitis, which could not be accomplished with conventional arthrography. Because of MR's superior soft tissue imaging capability, we were able to stage the impingement syndrome. Magnetic resonance also allowed evaluation of the glenoid labrum and capsuloligamentous structures and assessment of instability in a fashion similar to CAT. In most cases, information obtained from MR equaled or exceeded that obtained from conventional arthrography and CAT. With refinement in technique and increased experience, we believe that MR may replace arthrography in the evaluation of the shoulder.

Adolescent↗

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Juxtaacetabular ganglionic (or synovial) cysts: CT and MR features.

Radiographic findings include supraacetabular bone erosions, subchondral acetabular cysts, soft tissue masses with or without radiolucent inclusions representing nitrogen gas, joint space narrowing, and abnormal hip configuration. Associated tears of the acetabular labrum were confirmed by arthrography in two patients. Computed tomography and magnetic resonance imaging afforded improved delineation of soft tissue ganglia and their relationship to the acetabular bone, labrum, and hip joint. We report our experience with seven patients in whom various imaging examinations clearly documented the presence of soft tissue cystic lesions adjacent to the acetabulum; in six of the seven patients, significant clinical manifestations were evident in the affected hip. Such cysts, whether designated synovial or ganglionic in type, appear to be a frequently overlooked yet important cause of hip symptomatology.

Acetabulum↗

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Knee joint hyaline cartilage defects: a comparative study of MR and anatomic sections.

The value of routinely used MR sequences in the detection of focal changes of femorotibial articular cartilage was studied. T1-weighted, proton density, and T2-weighted SE as well as gradient echo images were acquired in 20 cadaveric knees (56-88 years old, mean 73.8 years). Three hundred five coronal and sagittal (3 mm) anatomic sections were prepared, and 82 areas of cartilage defects were identified. Initially, in an unblinded fashion, correlation of MR scans and anatomic sections was performed. Fifty-nine lesions (72.0%) were detectable on T1-weighted images, 57 (70.0%) with meniscal windowing, 49 (60.0%) on proton density images, 56 (68.3%) on T2-weighted images, and 54 (65.9%) on gradient echo images. Sixty-eight (83.0%) were visible on at least one type of imaging sequence. Most defects presented as a focus of abnormal signal. Subsequently, images of a subset of 35 pathologic and 35 normal cartilage surfaces were blindly evaluated by two osteoradiology fellows. Sensitivity was 71.4% for the detection of focal cartilage changes, specificity was 68.6%, and accuracy was 70.0%. We conclude that the value of those MR sequences that are routinely used in the analysis of internal derangements of the knee in the detection of focal defects of the hyaline cartilage is limited.

Aged↗

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Fluid-fluid levels in a unicameral bone cyst: CT and MR findings.

We present a case of unicameral bone cyst with fluid-fluid levels evaluated with CT and MRI. A literature review revealed that fluid levels within aneurysmal bone cysts, giant cell tumors, chondroblastomas, and tel-angiectatic osteosarcomas have been described.

Adolescent↗

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MR appearance of idiopathic synovial osteochondromatosis.

OBJECTIVE: A retrospective review of the MR examinations in 21 patients with idiopathic synovial osteochondromatosis (ISO) was performed to determine its MRI characteristics. MATERIALS AND METHODS: Twenty-one patients diagnosed with ISO had undergone MRI prior to surgery. The MR images were retrospectively evaluated for configuration and extent of lesion as well as for signal characteristics. RESULTS: Three distinct MR patterns were seen in ISO: A--lobulated homogeneous intraarticular signal isointense to slightly hyperintense to muscle on T1-weighted images and hyperintense on T2-weighted images (n = 3); B--pattern A plus foci of signal void on all pulse sequences (n = 17); and C--features of pattern A and B plus foci of peripheral low signal surrounding central fat-like signal (n = 2). The foci of signal void in pattern B and C corresponded to areas of calcification and the foci of peripheral low signal surrounding central fat-like signal in pattern C corresponded to areas of ossification. CONCLUSION: The MR appearance of ISO appears sufficiently unique to allow its differentiation from other causes of intraarticular pathology.

Adolescent↗

PubMedDate not supplied

Denervation hypertrophy of muscle: MR features.

OBJECTIVE: Denervation hypertrophy is an entity well recognized in the neurology literature, but with little mention in the radiology literature. Denervation hypertrophy occurs when a muscle paradoxically enlarges rather than atrophies in response to loss of innervation. The purpose of this report is to describe the MR appearance of true hypertrophy and pseudohypertrophy of muscle following denervation. MATERIALS AND METHODS: The clinical data and MRI findings in three patients with muscle enlargement due to denervation hypertrophy are reviewed retrospectively. Two women and one man aged 19-80 years were included. Denervation resulted from spinal stenosis in one patient, a herniated thoracic disc in another, and spina bifida with a tethered cord in the third. RESULTS: True hypertrophy of a single muscle was seen in one patient and pseudohypertrophy of two muscles was present in one patient. One patient had one muscle with true hypertrophy and one muscle with pseudohypertrophy. Electromyographic examination was performed and was consistent with denervation in two patients. Biopsy confirmation of denervation was obtained in two patients. All five abnormal muscles exhibited increased volume, well defined margins, and normal contour. In true hypertrophy the enlarged muscle was isointense with normal muscle on all MRI sequences. In pseudohypertrophy the MRI appearance was consistent with an excessive amount of fat interspersed throughout normal muscle. CONCLUSION: Magnetic resonance in these cases established muscle hypertrophy rather than neoplasm as the cause of a palpable mass. If muscle hypertrophy or pseudohypertrophy is seen on an MR examination of an enlarged extremity, the possibility of an underlying neurologic process should be considered.

Adult↗

PubMedDate not supplied

MRI of elastofibroma dorsi.

OBJECTIVE: To determine if the MR features of elastofibroma are sufficient for diagnosis of this neoplasm. MATERIALS AND METHODS: The MR studies of two patients with pathologically proven bilateral elastofibromas were reviewed retrospectively. RESULTS: In each patient, bilateral semilunar soft-tissue masses demonstrating signal intensities isointense to that of muscle were identified in the periscapular regions deep to the posterolateral musculature of the chest. Focal linear areas of fat were present. The biopsy specimens of both patients demonstrated a positive reaction to the elastin stains. CONCLUSION: A periscapular soft-tissue neoplasm demonstrating a pattern of linear alternating regions of high and intermediate signal intensity on T1- and T2-weighted spin-echo MRI should be sufficient to allow the diagnosis of elastofibroma.

Adult↗

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Pictorial essay. MRI of the glenoid labrum with gross anatomic correlation.

The objective of this pictorial essay is to illustrate the magnetic resonance image (MRI) appearance of the glenoid labrum and the perilabral structures with and without instillation of intraarticular contrast material. Ten cadaveric shoulder specimens underwent axial MRI using various MR pulse sequences. The shoulders then were transversely sectioned, and the gross morphology of the labrum and perilabral structures was evaluated and correlated with the MR images. The contrast-enhanced sequences allowed for improved anatomic visualization of the structures evaluated.

Aged↗

PubMedDate not supplied

MR arthrography of the elbow: normal anatomy and diagnostic pitfalls.

PURPOSE: Our goal was to determine the normal MR arthrographic appearance of the elbow and to identify the potential diagnostic pitfalls of this technique. METHOD: MRI with intra-articularly administered gadopentetate dimeglumine was performed in seven elbow joints derived from cadavers. Coronal, sagittal, and axial SE T1-weighted images with fat suppression and coronal 3D SPGR images with fat suppression were obtained in each elbow. The elbows were then sectioned. RESULTS: This technique allowed depiction of the cartilaginous surfaces of the elbow joint as well as clear delineation of the inner surface of the collateral ligaments. Potential diagnostic pitfalls included fat pads projecting into the joint, synovial folds, and cartilaginous pseudoerosions. CONCLUSION: MR arthrography allows clear delineation of the intraarticular structures of the elbow. However, diagnostic pitfalls exist that increase the difficulty of interpreting MR arthrographic images.

Aged↗

PubMedDate not supplied

Imaging articular cartilage defects with 3D fat-suppressed echo planar imaging: comparison with conventional 3D fat-suppressed gradient echo sequence and correlation with histology.

PURPOSE: Our goal was to shorten examination time in articular cartilage imaging by use of a recently developed 3D multishot echo planar imaging (EPI) sequence with fat suppression (FS). We performed comparisons with 3D FS GE sequence using histology as the standard of reference. METHOD: Twenty patients with severe gonarthrosis who were scheduled for total knee replacement underwent MRI prior to surgery. Hyaline cartilage was imaged with a 3D FS EPI and a 3D FS GE sequence. Signal intensities of articular structures were measured, and contrast-to-noise (C/N) ratios were calculated. Each knee was subdivided into 10 cartilage surfaces. From a total of 188 (3D EPI sequence) and 198 (3D GE sequence) cartilage surfaces, 73 and 79 histologic specimens could be obtained and analyzed. MR grading of cartilage lesions on both sequences was based on a five grade classification scheme and compared with histologic grading. RESULTS: The 3D FS EPI sequence provided a high C/N ratio between cartilage and subchondral bone similar to that of the 3D FS GE sequence. The C/N ratio between cartilage and effusion was significantly lower on the 3D EPI sequence due to higher signal intensity of fluid. MR grading of cartilage abnormalities using 3D FS EPI and 3D GE sequence correlated well with histologic grading. 3D FS EPI sequence agreed within one grade in 69 of 73 (94.5%) histologically proven cartilage lesions and 3D FS GE sequence agreed within one grade in 76 of 79 (96.2%) lesions. The gradings were identical in 38 of 73 (52.1%) and in 46 of 79 (58.3%) cases, respectively. The difference between the sensitivities was statistically not significant. CONCLUSION: The 3D FS EPI sequence is comparable with the 3D FS GE sequence in the noninvasive evaluation of advanced cartilage abnormalities but reduces scan time by a factor of 4.

Aged↗

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The Bennett lesion of the shoulder.

In this article we review the imaging features and significance of the Bennett lesion of the shoulder. Standard radiographic, computed arthrotomographic, and MR findings in three baseball pitchers diagnosed with Bennett lesions of the shoulder are discussed. A crescent-shaped region of mineralization at the posteroinferior aspect of the glenoid rim, consistent with a Bennett lesion, arises at the insertion of the posterior joint capsule. The diagnosis of this lesion, typically in baseball pitchers, should raise suspicion for associated labral and rotator cuff abnormalities.

Adult↗

PubMedDate not supplied

Condensing osteitis of the clavicle: MRI.

PURPOSE: Condensing osteitis of the clavicle is a rare benign disorder, seen exclusively in women and characterized by expansion and sclerosis of the medial end of the clavicle. The aim of this study was to evaluate the MR findings of this disorder. METHOD: MR images, obtained in four patients with evidence of condensing osteitis of the clavicle based on plain radiographs and clinical symptoms, included pre- and postcontrast T1 SE sequences, T2 SE images, GE images. RESULTS: MR images revealed consistent hypointense areas on T1-weighted SE images, corresponding to regions of clavicular sclerosis (n = 4). T2-weighted SE images showed signal characteristics ranging from low intermediate signal intensity in regions of sclerosis (n = 4). T2-weighted GE images revealed moderate to high signal intensity presumably related to bone marrow edema (n = 2). Contrast-enhanced T1-weighted SE images were characterized by mild to extensive intraosseous and periosseous enhancement of signal intensity (n = 2). CONCLUSION: MRI in cases of condensing osteitis of the clavicle reveals variable findings perhaps indicative of different stages of activity in this disease.

Adult↗

PubMedDate not supplied

Ligaments of the ankle: normal anatomy with MR arthrography.

PURPOSE: Our purpose was to define the normal MR arthrographic anatomy of ankle ligaments. METHOD: Prior to injection of intraarticular gadolinium in cadaveric ankle joints, proton density and T2-weighted images were obtained to assess the integrity of the ligaments and tendons as well as the amount of preexisting joint effusion. Following injection of 10 ml of contrast agent (gadopentetate dimeglumine 1:250, Omnipaqe 300, Knox gelatin 50%, and methylene blue), T1-weighted images with fat saturation in axial, oblique axial, coronal, and sagittal planes were obtained in neutral, dorsiflexion, and plantar flexion positions. Specimens were sectioned, allowing anatomic and MR correlation. RESULTS: Contrast agent outlining anterior and posterior aspects of the anterior talofibular ligament and posterior talofibular ligament (PTAF) was a normal finding, related to anterior and posterior recesses of the ankle joint that extend out beyond these ligaments in an anteroposterior direction above the level of the ligaments. Intraarticular contrast material allowed resolution of superficial and deep components of the posterior tibiofibular ligament. Both were seen separately from PTAF with dorsiflexion. Posterior intermalleolar ligament was not present in our specimens. Visualization of calcaneofibular ligament was much improved by contrast material outlining the articular aspect of the ligament. Visualization of the syndesmotic ligamentous complex also was improved by contrast material outlining the articular side of the ligaments and separating them from adjacent bone. Superiorly, the distribution of contrast agent was limited by the interosseous ligament. Visualization of the medial collateral ligaments was not improved by the presence of the intraarticular contrast material. CONCLUSION: MR arthrography of the ankle allows improved visualization and evaluation of the lateral and syndesmotic ligamentous complex.

Ankle Joint↗

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MRI of the common peroneal nerve: normal anatomy and evaluation of masses associated with nerve entrapment.

The objective of this pictorial essay is to illustrate the MR appearance of the common peroneal nerve and the appearance of masses that have been associated with peroneal nerve entrapment. Four human cadaveric knees underwent axial MRI utilizing a T1-weighted SE sequence. One knee was dissected by an orthopedic surgeon and three knees were transversely sectioned, and the gross morphology of the common peroneal nerve and the perineural structures was evaluated and correlated with the MR images.

Adolescent↗

PubMedDate not supplied

Tibiofibular syndesmosis: high-resolution MRI using a local gradient coil.

PURPOSE: Our goal was to correlate high-resolution MR images of the tibiofibular syndesmosis with anatomic sections. METHOD: MRI was performed inside a local gradient coil on six cadaveric feet taped in 10-20 degrees dorsiflexion and 40-50 degrees plantar flexion by using axial and coronal T1-weighted SE sequences. After imaging, the specimens were frozen and sectioned into 3-mm-thick slices along the MR planes. Images were correlated with the anatomic sections. RESULTS: MRI depicted the anatomy of the tibiofibular syndesmosis and surrounding structures. With the foot taped in dorsiflexion, axial imaging provided optimum views of the anterior, posterior, interosseous, and transverse tibiofibular ligaments. Coronal images allowed visualization of the entire course of the anterior, posterior, and transverse tibiofibular ligaments. The multifascicular appearance of the anterior tibiofibular ligament was best visualized in coronal sections. With the foot taped in dorsiflexion or in plantar flexion, it was possible to distinguish the posterior tibiofibular ligament and transverse tibiofibular ligament from the posterior talofibular ligament in all specimens. CONCLUSION: High-resolution MRI using a local gradient coil provides excellent delineation of the ligaments of the distal tibiofibular syndesmosis.

Aged↗