Biomedical subjects
Publications and source records attributed to J Tehranzadeh.
Ankle ligament sprains are the most frequent sports injury, and radiographic evaluation of the ankle accounts for 10% or all radiographic examinations requested from an emergency department. This article reviews the diagnosis of the ankle sprain and the anatomy and injuries of the ankle ligaments.
MRI is highly valuable in evaluation of tendons and ligaments of the lower extremities. In this context, MRI is predominantly used in the setting of trauma and sports-related injuries. Tendons and ligaments have a crucial role in the stability and motion of joints in the peripheral skeleton. Tendinitis, tenosynovitis, tendinosis (degeneration of tendon), partial tear, and complete tear of tendons and ligaments are readily detected by MRI. Although interpretation of signal intensities and differentiation of some of these conditions may be difficult, knowledge of the clinical setting, traumatic circumstances, and mechanism of injury would lead to the proper diagnosis. In this article, traumatic and sports-related injuries of tendons and ligaments of the pelvis, knee, ankle, and foot are systematically reviewed.
MRI is valuable in evaluation of tendons and ligaments in sports-related injuries. Tendons and ligaments show dark signal intensity on all MR sequences. Alteration in size, shape, continuity, and signal intensity of these structures can be well visualized with MRI. Impingement syndrome is the leading cause of atrophy and degeneration of the rotator cuff. Shape of the acromion, presence of subacromial spur, and involvement in certain sport activities that lead to shoulder instability may cause impingement of the rotator cuff. This article systematically reviews the injuries of tendons and ligaments in the spine, shoulder, elbow, wrist, and hand.
Findings from magnetic resonance (MR) imaging examinations of 194 knees were interpreted retrospectively with a new classification, including not only signal intensity but morphologic abnormalities. All findings were correlated with prospectively recorded results from arthroscopic examinations performed by a knee subspecialist. Meniscal MR imaging findings were expanded to eight types in this study. Positive predictive values for each type of finding and overall accuracy were calculated. Several potential sources of error that could be differentiated through pathologic change were recognized. Sensitivity and specificity of MR imaging findings were, respectively, 95% and 74% for the medial meniscus and 86% and 90% for the lateral meniscus. As the classification grade increased, the likelihood of meniscal tear also increased. Medial meniscal tears tended to occur in a predictable pattern, extending from the posterior to the anterior horn. Thus, when a definite tear of the body or anterior horn of the medial meniscus is present, a tear of the posterior horn should be suspected, even if the findings are not convincing. This expanded classification may be useful for radiologists in expressing their level of confidence in a particular MR imaging finding suggestive of meniscal injury.
The authors retrospectively reviewed the charts, radiographs, and other accompanying imaging studies of 45 patients with musculoskeletal abnormalities associated with human immunodeficiency virus (HIV) infection. These included 19 patients with osseous infection, including eight with osteomyelitis, seven with bacillary angiomatosis (six of whom were described in a previous report), and four with septic arthritis; 10 with bacterial myositis (six of whom were described in a previous report); seven with non-Hodgkin lymphoma; five with hypointense marrow signal intensity at magnetic resonance imaging; two with Kaposi sarcoma; one with polymyositis; and one with psoriasis. The musculoskeletal system can be affected by a variety of abnormalities in association with HIV infection. Knowledge of their existence and characteristic appearance is valuable to radiologists for diagnosis and to clinicians for detection and appropriate treatment.
Magnetic resonance imaging (MRI) has provided an ideal means, unmatched by other preexisting modalities, of examining musculoskeletal abnormalities, particularly those involving tendons and ligaments in the lower extremities. Lack of motion artifact, convenience of application of surface coil, and absence of overlying structures have made the lower extremities ideally suited to MRI. In addition, the abundance of adjacent adipose tissue provides a superb contrast background. Although evaluation of trauma remains the most common reason for MRI examination, many other conditions may also affect tendons and ligaments. As in other soft-tissue, chondral, and osteochondral lesions, MRI provides exquisite details of abnormalities in these structures. Part II of this review systematically reviews the abnormalities of tendons and ligaments in the pelvis and lower extremities.
Magnetic resonance imaging (MRI) has proven to be an ideal technique for evaluating tendons and ligaments, which, because of their fibrous structure, have a low signal intensity on all sequences. Trauma and a wide variety of other conditions cause aberrations in the normal appearance of these structures, ranging from minor alterations in shape, size, appearance, and continuity to various changes in signal intensity within the tendon, tendon sheath, and ligament on different sequences. The purpose of this paper is to review MRI findings in patients with abnormalities of tendons and ligaments in the spine and upper extremities.
Radionuclide imaging, if applied with an organ system approach, is useful in the diagnosis of the AIDS (acquired immunodeficiency syndrome)-related complex. Specific pathologic processes can be suspected on the basis of uptake patterns. The intensity and pattern of pulmonary uptake and concomitant nonpulmonary uptake of gallium provide guidelines for distinguishing among various opportunistic pulmonary pathogens. Gastrointestinal and extra-gastrointestinal tract uptake of gallium aids distinction among fungal, mycobacterial, and viral infections and neoplasms. Patterns of spleen uptake of technetium-99m sulfur colloid and gallium allow differentiation between neoplasm (Kaposi sarcoma) and infection (with mycobacteria). Skeletal and soft-tissue abnormalities can be characterized and differentiated on the basis of bone scan and other radionuclide scan findings. Thallium uptake in brain tumors (and not in areas of infection) allows brain lesion discrimination. In the proper clinical setting, AIDS nephropathy has a characteristic gallium uptake pattern. Cardiac abnormalities (including functional) can also be assessed with scintigraphy. With knowledge of these organ-specific patterns and with correlative imaging studies, the manifestations of AIDS can be differentiated and appropriate treatment instituted.
Early diagnosis and detection of osteomyelitis and differentiation of soft-tissue infection from bone involvement is a difficult clinical and imaging problem. Magnetic resonance imaging has proven to be as sensitive as bone scintigraphy in the early detection of osteomyelitis, and, with its superior spatial resolution, MR is often more specific than planar scintigraphy in differentiating bone from soft-tissue infection and separating arthritis, cellulitis, and soft-tissue abscess from osteomyelitis. In several comparative studies, MR has been more advantageous in detecting the presence and determining the extent of osteomyelitis over scintigraphy, CT scan, and conventional radiography. MRI may facilitate differentiation of acute from chronic osteomyelitis and may help to detect foci of active infection in the presence of chronic inflammation or posttraumatic lesions. MRI has a large role in evaluating the presence and extent of spondylitis and epidural abscess and certain distribution features may help recognize tuberculous spondylitis. Gadolinium-enhanced MR could be helpful in delineating the meninges and demonstrating the border and extent of epidural abscesses.
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Assessment of healing of a scaphoid fracture, which may be associated with delayed fusion and nonunion, is a challenging task for the radiologist. Thirty cases of clinically suspected nonunion scaphoid waist fractures with inconclusive plain radiographs were prospectively studied by means of stationary tomography and lateral flexion-extension tomography. The angle between the two scaphoid fragments as seen in extension was measured and compared with the angle as seen in flexion. A difference of 10 degrees or greater between flexion and extension was considered significant. This was noted in 14 of 15 cases of nonunion. Fifteen cases without angle differences were accurately diagnosed as stable. One false-negative case was noted, which on review was attributed to a limited extension view. Flexion-extension tomography is a highly valuable diagnostic modality in evaluating the stability and healing of scaphoid fracture and is superior to conventional (stationary) tomography.
Chondral and osteochondral impactions are insults to articular cartilage and subchondral bone of the femoral head during hip dislocation. To evaluate the frequency and sites of femoral head impaction, we reviewed CT scans of 35 patients with hip dislocation (32 posterior and three anterior). Osteochondral impaction fractures were present in 20 (63%) of the 32 patients with posterior hip dislocation and in all three patients with anterior dislocation. In patients with posterior dislocation, the impaction occurred anteriorly in an arc between the 11-o'clock and 1-o'clock positions in all seven cases (100%) of right-sided dislocation and in eight (61%) of 13 cases of left-sided dislocation. Twelve (60%) of the 20 patients with femoral head impaction fracture underwent surgery; osteochondral impaction was substantiated in all 12. In those with anterior dislocation, osteochondral impaction occurred at the posterolateral aspect of the femoral head in an arc between the 4-o'clock and 5-o'clock positions. A high rate of osteochondral impaction after hip dislocation was detected in this series. Observing the site of femoral head impaction allows determination of the type of original dislocation. Alternatively, when the type of original dislocation is known, the site of femoral head impaction can be predicted.
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Twenty-two painful hip prostheses were studied prospectively with plain radiography, aspiration and arthrography, Tc-99m phosphate bone imaging, and gallium imaging to evaluate loosening, infection, or both and to compare the accuracy of these modalities. Fifteen prostheses were revised yielding 14 loose femoral and eight loose acetabular components. Five proved to have infected prostheses. Arthrograms, plain radiographs, and bone scans are highly sensitive in detecting loosening of the femoral component. This study confirmed a previous retrospective study in demonstrating that accuracy of diagnosis of an abnormal acetabular component using all four modalities is less than that for the femoral component. In infected prostheses, phosphate bone imaging showed high sensitivity of a pattern that accurately diagnosed all the infected cases, whereas gallium imaging missed one case.
A case of a hemangiosarcoma involving the bones of the foot in a diabetic patient who had swelling of the left foot is reported. Radiographs demonstrated multiple lytic areas throughout the bones of the foot. Clinically and radiographically, infection was suspected, but the biopsy revealed the presence of tumor. Metastases to the tibia were found and an above the knee amputation was performed. Chemotherapy was given, but 6 months later the patient died. Hemangiosarcoma is known to involve the different bones of the foot in a "multicentric" fashion and should be considered in the differential diagnosis of lytic lesions of multiple bones of the lower extremities.
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In an attempt to understand the relation between the outcome of chemonucleolysis treatment of lumbar discs and the presence of spondylosis (degenerative process) of the lumbar spine, 40 cases of disc herniation with subsequent intradiscal chymopapain injection (chemonucleolysis) were reviewed. Thirty-eight patients had plain radiographs, 25 had myelography, 28 had computed tomography (CT), and 15 had both myelography and CT. A review of these examinations revealed that 24 patients had minimal or mild spondylosis (group 1) and 13 patients had moderate spondylosis (group 2). Only one patient had a severe spondylosis (group 3). Chemonucleolysis failed in 8/24 (33%) patients from the first group and 2/13 (15%) cases from the second group. Therefore, the presence or absence of even moderate spondylosis did not affect the treatment success rate. A review of the 11 failed cases revealed spinal canal stenosis in three cases and a large disc herniation in two (one case with a myelographic block). Another case had a sequestered disc fragment. In two further cases, the disc herniation was far lateral with complete occlusion of the lateral foramen; another case exhibited severe degenerative changes of facet joints. In two other cases, treatment failure could not be explained by any radiographic finding. Of three patients with large disc herniation, only one responded successfully to intradiscal injection of chymopapain. Chemonucleolysis, however, failed in the only patient in the third group who had severe spondylosis of the facet joint.
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