Biomedical subjects
Publications and source records attributed to M Rafii.
This article discusses the anatomy of the menisci and various signal abnormalities. Morphologic changes indicative of degenerative disease, degenerative tear, intra- and para-meniscal cysts, and traumatic tear are also covered.
Familiarity with normal anatomy and pathologic features of the capsulolabral complex as well as high resolution imaging are important factors in achieving a consistently high accuracy rate in diagnosis of glenohumeral instabilities by conventional MR imaging. The various types of glenoid labrum lesions and features that are most often associated with glenohumeral instability are defined.
Because the shoulder is the most mobile joint in the body, it is naturally predisposed to several disorders. The most commonly encountered disorders requiring diagnostic imaging are rotator cuff disease and glenohumeral instability. Plain film radiography and arthrography have for many years been the mainstays of shoulder imaging. CT added a third dimension to shoulder imaging, improving its sensitivity with respect to glenoid labral pathology. Ultrasonography of the rotator cuff showed early promise in noninvasive evaluation of cuff tears, but it did not gain universal acceptance because of various negative factors, including inadequate visualization of the cuff, poor results regarding partial tears, and most importantly, operator dependency. The development of MR imaging afforded the radiologist improved comprehensive visualization of the shoulder joint in a noninvasive manner.
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The signal intensity patterns of rotator cuff lesions at magnetic resonance (MR) imaging were evaluated in 80 patients who had surgical correlation and in 13 asymptomatic individuals (14 shoulders). Six cadaver shoulders were examined with MR, and histologic correlation was obtained in four. All studies were performed at 1.5 T with a flexible circular surface coil. The accuracy of MR imaging in detection of full-thickness cuff tears (31 patients) was 0.95 and of partial thickness tears (16 patients), 0.84. The most common and accurate pattern for full-thickness cuff tears (22 of 31 tears) was a region of intense signal seen on T2-weighted images. Less often the torn region consisted of an extremely degenerated and attenuated tendon with moderate signal intensity or was obscured by low-signal-intensity scar. The intense signal pattern on T2-weighted images was also accurate, although a less common finding (seven of 16 cases), in the diagnosis of partial tears. Tendinitis was recognized as focal or diffuse regions of increased signal intensity or a nonhomogeneous pattern of increased signal often associated with tendinous enlargement. In some patients, manifestations of subacromial-subdeltoid bursitis was present. Tendon degeneration was also manifested as regions of increased signal intensity. Some similarity and overlap of signal patterns of partial interstitial tears, tendinitis, and tendon degeneration are observed.
Magnetic resonance (MR) imaging of the wrist was performed in 35 patients with specific complaints of pain and soft-tissue swelling in the medial side of the wrist. Twenty of the 35 subsequently underwent surgery. In 14 of the patients who underwent surgery, a diagnosis of triangular fibrocartilage (TFC) tear was made at MR imaging; in 13 of the 14 the tear was confirmed by surgical findings. In the six patients with an MR diagnosis of an intact TFC, surgical findings confirmed the diagnosis. These patients were operated on for an abnormality in the vicinity of the TFC (avascular necrosis, ganglion cyst, xanthoma). On the basis of findings from the 20 patients with surgical correlation, the accuracy of MR imaging in the detection of TFC tears was 95%. MR imaging is a valuable noninvasive method in the study of pathologic conditions of the TFC.
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Computed tomography was performed in 100 patients for additional evaluation of suspected skeletal metastases following radionuclide bone scanning in 86 patients and conventional radiography in all. A retrospective review of these cases revealed that the majority (78%) involved the spine and pelvis. Computed tomography contributed to the diagnosis of a malignancy by revealing a definite destructive lesion of bone in 27 patients who had an abnormal radionuclide bone scan, a normal or inconclusive radiograph, or both. It excluded a malignant lesion in 19 patients. In 38 patients, computed tomography provided additional information that contributed to such aspects of patient care as obtaining tissue diagnosis, determining the extent of lesions, and evaluating the response to treatment. False diagnoses were made in two patients. Detection by computed tomography of a skeletal lesion and histologic documentation, frequently by computed tomography-guided percutaneous needle aspiration biopsy, greatly curtailed an otherwise extensive search for the primary site. Furthermore, this information altered the treatment plan by obviating the need for radical resection or biopsy of the primary tumor and by directing the choice of an appropriate chemotherapeutic regimen.
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Forty-three professional and amateur athletes with persistent shoulder pain that interfered with their sports activities were evaluated by computed tomographic (CT) arthrography. In 19 patients, glenohumeral instability (14 anterior, two posterior, three multidirectional) was diagnosed with CT arthrography based on the simultaneous presence of labral and capsular lesions. The findings were crucial in establishing the diagnosis of instability in six patients in whom the condition was not suggested or could not be confirmed clinically. Another significant injury consisted of labral lesions not associated with glenohumeral instability. These tears often involved the anterior and parasuperior segments of this structure. Other, less frequently detected lesions included segmental labral enlargement and several labra with abnormal orientation (everted labrum). Early onset of degenerative disease was present in many athletes, especially those with a long history of sports activity. CT arthrographic findings were correlated with arthroscopic or surgical results in 19 patients.
Computed tomography (CT) of the lumbar spine without and with intravenous administration of contrast medium was performed in 143 consecutive patients who had previously had spine surgery for disk herniation and had persistent or recurrent symptoms. Fifty-two patients underwent surgical reexploration. It was possible to make the diagnosis of normal postoperative status, disk herniation, or scarring in 31 (60%) of the 52 patients with the use of CT scans without intravenous contrast medium. CT with intravenous contrast enhancement was useful in 12 of the remaining patients (23%). Enhancement of the margins of a herniated disk occurred in 37 (71%) of the patients. There was near-homogeneous enhancement of postoperative scarring in 34 (65%) patients. Intravenous contrast medium was particularly helpful when disk herniation and scarring were both present, by delineating the margins of a herniated disk and enhancing the entire substance of the scar. In symptomatic postoperative patients, CT of the lumbar spine without intravenous contrast medium should be performed initially. If a definitive diagnosis is not established, CT with intravenous contrast enhancement should be considered.
Fractures of the tibial plateau consist of two important components. One is depression of the plateau surface and the other a detached and peripherally displaced component referred to as the split fragment. The classification of these fractures is based on the morphologic appearance as well as the location of the above components. The surgical treatment of these fractures is dependent upon several factors, including the type of fracture, the degree of the fracture depression, and fracture fragment separation as well as the patient's age and physical condition. The degree of the plateau depression is a particularly important criteria for surgical-treatment planning. However, the anatomic configuration of the proximal tibia is such that the fractures of these regions are not adequately visualized on conventional radiographs. In the past, conventional tomography was routinely employed for evaluation of tibial plateau fractures. Recently, computed tomography (CT) has shown to be a more accurate and easier method for evaluation of these fractures. CT can be performed without removal of the knee brace or cast and usually requires less than 12 axial images. Furthermore, the degree of fracture separation and depression can be measured by computerized technique. CT scanning is a reliable method for evaluation and an accurate classification of tibial plateau fractures.
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Quantitative computerized tomography (QCT) of vertebral bodies could reveal metastatic spread of prostatic cancer before such lesions are seen with standard examinations. Focal increase in the density of the spongious bone in face of normal bone scan and serum acid phosphatase is suggestive of metastasis, but certitude is gained only if further increase in density or structural bone changes are demonstrated on follow-up studies. QCT also may provide an objective measurement of tumor response to therapy.
Computed tomography of 16 spinal chordomas revealed lytic lesions, or lytic and blastic lesions, of 2 or more adjacent vertebrae and a fairly well-delineated soft tissue mass in 16 patients. Intravenous contrast enhancement revealed multiple zones of hypodensity in 5 tumors pathologically proved to contain areas of cystic degeneration. Invasion of the epidural space was noted on computed tomography in 2 vertebral and 7 sacral lesions, and on myelography in 7 vertebral lesions. Computed tomography is ideal for delineation of the soft tissue component of these lesions, detection of sacral lesions at an early stage, planning of surgical excision or irradiation treatment, and detection of recurrence.
An adult patient with undiagnosed osteogenesis imperfecta presented with a history of multiple fractures. Radiographs could not definitively diagnose the underlying abnormality. The radionuclide bone image suggested the presence of a skeletal dysplasia, and prompted the histopathologic review of fracture fragments. The scan appearance of osteogenesis imperfecta in the adult and possible underlying mechanisms for the radiopharmaceutical distribution are discussed.