Biomedical subjects
Publications and source records attributed to D Resnick.
High resolution MRI was performed on four cadaveric foot specimens of human feet to demonstrate the ligaments of the tarsal joints. Spin echo T1 images were obtained using a local gradient coil that produces 6 G/cm and 100 A in all three axes. The best views for each of the individual ligaments were determined. High resolution MRI potentially can demonstrate most of the intertarsal ligaments.
PURPOSE: The purpose of this work was to establish the optimal means of evaluation of the rotator cuff interval (RCI) and rotator interval capsule and demonstrate normal anatomy of the RCI using MR imaging and MR arthrography. METHOD: MR arthrography was performed in 32 cadaveric shoulders. In 20 cases, MR imaging was completed prior to arthrography. Pre- and postarthrography studies included standard imaging planes. Images were evaluated by the consensus of two musculoskeletal radiologists with attention to the RCI, rotator interval capsule (measurements on postarthrographic studies), and crossing structures. In five cases, specialized imaging planes were performed after arthrography. RESULTS: The RCI, rotator interval capsule, and crossing structures were best evaluated by MR arthrography. The anteroposterior dimension of the rotator interval capsule could be best depicted on postarthrogram images. CONCLUSION: MR arthrography, with both standard and specialized imaging planes, is a useful way to evaluate the RCI, the rotator interval capsule, and its crossing structures.
PURPOSE: The purpose of this work was to demonstrate nerve anatomy of the medial plantar (MP) and lateral plantar (LP) nerves and the first branch of the lateral plantar (FBLP) nerve as depicted with MRI. METHOD: High resolution MRI of the heel was performed with a standard transmit-receive extremity coil in six human cadaveric specimens using sagittal, axial, and coronal T1-weighted spin echo images. The specimens were then sectioned in the axial and coronal planes. RESULTS: MRI depicted the MP and LP nerves arising from the posterior tibial (PT) nerve. Assessment of the anatomic course and trifurcation of the PT nerve into the plantar nerves and the FBLP nerve was best seen in the sagittal plane. Various portions of these nerves were visualized also in the axial and coronal imaging planes. CONCLUSION: MRI may demonstrate the origin, course, and branching of nerves in the heel and can provide a means for assessment of the patient presenting with chronic heel pain and suspected entrapment neuropathy.
Three patients with adenocarcinoma of the prostate and metastasis to the cervical spine required stabilization to prevent neurologic impairment. In each instance, a Halo cast was used. This method of stabilization is easily applied and well suited for patients with shortened life expectancy. It allows protection of the cord while chemotherapy and radiation are administered.
The infrapatellar fat pad of Hoffa is an intracapsular structure that is routinely visualized on magnetic resonance images of the knee. Because disease in this region is not uncommon, it is important to be familiar with the various pathologic entities that may occur here. Abnormalities that are intrinsic to this fat pad include Hoffa disease, intracapsular chondroma, localized nodular synovitis, postarthroscopy and postsurgery fibrosis, and shear injury. In addition, the infrapatellar fat pad may be involved secondarily from extrinsic processes, including articular disorders (eg, joint effusion, intraarticular bodies, meniscal cyst, ganglion cyst, cyclops lesion), synovial abnormalities (eg, pigmented villonodular synovitis; hemophilia; synovial hemangioma; primary synovial chondromatosis; chondrosarcoma; lipoma arborescens; rheumatoid, seronegative, and septic arthritis; arthritis associated with inflammatory intestinal disorders; synovitis associated with primary osteoarthritis), and anterior extracapsular abnormalities. The approach to pathologic processes involving the infrapatellar fat pad of Hoffa is simplified when one is familiar with regional anatomy and possible differential diagnostic considerations.
The ligaments of the wrist have been demonstrated with magnetic resonance (MR) imaging by many authors. Distinction has been made between the extrinsic, or radiocarpal and ulnocarpal, ligaments and the intrinsic, or intercarpal, ligaments. The stability of the wrist depends on numerous ligaments: The volar ligaments are important stabilizers of the wrist, whereas the dorsal ligaments are less crucial for wrist stability. An MR imaging protocol that demonstrates these structures with high resolution has been developed. Cadaveric wrists are imaged with a spoiled gradient-recalled-echo volume-acquisition technique with fat suppression after three-compartment enhancement with a contrast agent containing gadolinium. The specimens are then sectioned, and the anatomic and pathologic findings are correlated with the findings on the MR images. The extrinsic and intrinsic ligaments of the wrist are clearly demonstrated with this technique. This protocol was designed for anatomic study and promotes understanding of the anatomy and biomechanics of the wrist; it is not intended for clinical use.
Findings at high-resolution magnetic resonance (MR) imaging of the lateral and medial collateral ligaments of the ankle were compared with findings in anatomic sections from cadavers. MR imaging of six cadaveric feet was performed with a newly developed local gradient coil and axial and coronal T1-weighted spin-echo sequences. Axial imaging provided optimum views of the anterior and posterior talofibular ligaments, the deep layers of the medial collateral ligament, and the tibionavicular ligament. Coronal imaging allowed complete visualization of the calcaneofibular, posterior talofibular, tibiocalcaneal, and posterior tibiotalar ligaments. In both imaging planes, differentiation of the deep and superficial layers of the medial collateral ligament was possible. Differentiation between the syndesmotic complex and the lateral collateral ligament was accomplished easily; in particular, differentiation of the posterior tibiofibular ligament from the posterior talofibular ligament was not difficult because of the differing insertions of these ligaments. The inhomogeneous appearance of the medial collateral ligament and the posterior talofibular ligament on MR images correlated with areas of fatty tissue on corresponding microscopic sections. High-resolution MR imaging with a newly developed local gradient coil allows excellent visualization of the lateral and medial collateral ligaments of the ankle.
The Hill-Sachs lesion is an important indication of previous anterior shoulder dislocation. We created Hill-Sachs lesions by using cadaveric humeri. Roentgenographs of these cadaveric humeri in the standard projections were then taken. Under fluoroscopy, new projections of the cadaveric humeri were obtained. In a clinical study, 15 patients (14 men and 1 woman; age range, 23 to 63 years; mean, 30 years) with known recurrent anterior shoulder dislocations were evaluated by using standard and new roentgenographic projections. On the basis of the cadaveric and clinical studies, the optimal methods for detecting Hill-Sachs lesions include the following three roentgenograms: anteroposterior view of the glenohumeral joint with the humerus in 45 degrees internal rotation, the notch (Stryker) view, and the modified Didiee view.
Three patients who had various types of glenohumeral joint instability, and in whom computed tomography (CT) was utilized as an additional diagnostic modality, are presented. In two of the three patients, routine radiography supplemented with special views documented the presence of a Hill-Sachs lesion; in the third, an equivocal abnormality was apparent. In all three individuals, CT verified the presence of a Hill-Sachs lesion; in one patient, there was also a Bankart deformity. CT represents a new and important modality that may be applied to the diagnostic evaluation of patients with unstable shoulders.
The object of this study was to evaluate the effect of a patellar realignment brace on patients with patellar subluxation or dislocation. Twenty-one patients (24 patellofemoral joints) with clinical evidence of patellar subluxation (N = 16) or dislocation (N = 5) were examined with the joint inside a positioning device to allow active-motion, kinematic magnetic resonance imaging. To analyze the patellar tracking pattern, the same imaging parameters (patellar tilt angle, bisect offset, and lateral patellar displacement) and section locations were used before and after application of a patellar realignment brace. No statistically significant differences were found in any of the three parameters for the patellofemoral relationships before or after wearing the patellar brace. The results indicated no stabilizing effect of the tested brace in patients with patellar subluxation or dislocation during active joint motion.
The hallux is subject to numerous surgical procedures and very little is known about its blood supply. Arteriographic studies were performed in six cadaver specimens to identify the major arterial supply to the hallux. Discrepancies with now known anatomical models were discovered. In this study, the major arterial supply to the hallux appeared to originate from the lateral digital artery. In addition, two transverse digital arteries were noted to emit the nutrient arteries of the phalanges. Examination of other arteriographic studies sustained our results.
The authors review the entity of traumatic intermetatarsal neuroma. A thorough evaluation with the aid of magnetic resonance imaging is illustrated. This can be a beneficial modality in the initial identification, or differentiation of recurrent, pathologic lesions.
The authors discuss a recently described bone graft material substitute derived from sea corals. They briefly review its background leading to the potential for clinical use. Radiologic evaluation is provided, with attention directed to its characteristics, compared with other bone grafts.
The authors present a variety of radiographic pathologies affecting the foot and ankle. Some of these are intrinsic to the body part, while others reflect more systemic etiologies. Queries are initially posed, answers provided, and then justification of the correct response afforded.
Drs. Mitchell et al. have provided a valuable radiologic perspective of trauma to the ankle and foot. Previous articles in this series consisted of analyzing ankle fractures, ligamentous injuries, trauma to the talus, calcaneus, and midfoot. Plain x-ray films and sophisticated studies will assist in recognizing conditions described in this series of papers. The following represents the final part of this discussion.
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The authors review magnetic resonance imaging characteristics for the synovial sarcoma. This entity is most frequent in the lower extremity, predominantly in young males. Its difference in the T2 and T1-weighted image is discussed.
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