Biomedical subjects
Publications and source records attributed to R G Dussault.
With high-resolution MR imaging, the collateral ligament of the elbow can be directly evaluated; thus ligamentous injuries can be detected, localized, and graded. The functional anatomy of the ligaments of the elbow is reviewed. The normal appearance of the ligaments on MR images as well as the clinical and MR imaging findings of medial and lateral collateral ligament injury are presented.
The authors present a review of the anatomy of the major bursae around the shoulder joint and discuss the use of the different imaging modalities which demonstrate their radiologic features. The calcified subacromial-subdeltoid bursa has a characteristic appearance on plain radiographs. When inflamed it can be visualized by ultrasound and magnetic resonance imaging. Calcific bursitis may involve the subcoracoid bursa. This bursa may mimic adhesive capsulitis of the shoulder or complete rotator cuff tear when injected inadvertently during shoulder arthrography. Less well known are three coracoclavicular ligament bursae. These are also subject to calcific bursitis and have a typical radiologic appearance.
RATIONALE AND OBJECTIVES: We assessed the impact of ankle radiographs on referring physicians' diagnoses and treatment of acute ankle injuries. METHODS: Twenty emergency department physicians prospectively completed questionnaires before and after radiography on 101 patients with acute trauma receiving ankle radiographs. The questionnaires asked physicians to estimate the probability (0-100%) of their most likely diagnosis before and after receiving the radiographic information. We also asked their anticipated and final treatment plans. We calculated the mean gain in diagnostic confidence percentage and the proportion of patients with changed initial diagnoses or anticipated management. RESULTS: The mean gain in diagnostic certainty from ankle radiographs was 34% (95% confidence interval [CI] = 28-40%). Ankle radiographs changed physicians' initial diagnoses in 37% (95% CI = 28-47%) of the patients. Immediate clinical management changed in 30% (95% CI = 22-40%) of the patients. CONCLUSION: Plain ankle radiographs have considerable impact on referring physicians' diagnoses and treatment of acute ankle trauma.
PURPOSE: To determine how often lateral-compartment bone contusions are seen on magnetic resonance (MR) images of knees in adolescents with intact anterior cruciate ligaments (ACLs). MATERIALS AND METHODS: MR images obtained in 53 adolescent patients (30 male, 23 female; aged 10-20 years) were reviewed to detect bone contusions in the posterolateral tibial plateau or the lateral femoral condyle. ACLs were also evaluated with accepted criteria for the diagnosis of ligamental disruption. Only patients referred for evaluation of a knee injury or mechanical symptoms were included. RESULTS: Five patients with bone contusions had an intact ACL at MR imaging. One of the five had arthroscopic confirmation. Fifteen other patients had complete ACL disruptions: 13 of these patients had typical bone contusions; the other two had no bone abnormalities but had chronic ACL tears. Thus, 28% of the 18 patients with typical bone contusions had intact ACLs. CONCLUSION: Adolescents may have the same pattern of contusions as adults but may maintain an intact ACL owing to increased ligamentous laxity.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
This article describes the steps involved in production of a computer teaching module on the radiographic diagnosis of arthritis. The module was part of a research project aimed at producing seven computer teaching modules. Several staff radiologists and residents were involved, as well as a consultant on medical education. A generic shell program was used as a frame for all seven modules. The author of each module then filled in the empty pages of the shell with the appropriate text and images, along with additional short program scripts. The module on the radiographic diagnosis of arthritis described and illustrated the basic radiographic signs of arthritis. Practice cases were also included, and interactive and hypermedia features were implemented. The modules were then evaluated by means of task list tests and interviews. The experience was judged to have been successful, although the amount of time spent by some authors was much more than expected.
OBJECTIVE: The purpose of this study was to evaluate the MR imaging characteristics of Achilles tendons in patients at risk for tendon xanthomas because of familial hyperlipidemia and to compare these findings with those seen on plain radiographs and physical examination. We also wished to determine if MR imaging could be used to differentiate xanthomas from traumatic tendinopathy in a second group of patients who had no history of hyperlipidemia but who had a history of trauma to the Achilles tendon. SUBJECTS AND METHODS: We evaluated the MR imaging studies of 26 Achilles tendons in 13 patients with heterozygous familial hypercholesterolemia (n = 11) and type III dysbetalipoproteinemia (n = 2). The size, shape, and signal characteristics of the Achilles tendon were recorded. A tendon was considered abnormal by MR if there was high signal, a convex anterior border, or an anteroposterior measurement greater than 7 mm. Findings on plain radiographs and physical examination of the Achilles tendons were evaluated in the same group of patients. In the group of patients with hyperlipidemia, palpable abnormalities of the Achilles tendon were present in 14 of 26 tendons. Plain radiographs were interpreted as showing abnormalities in 18 of the 26 tendons. In a second group of 21 tendons in patients with no history of hyperlipidemia but with traumatic tendinopathy, studies were evaluated for the size, shape, and signal characteristics of the Achilles tendon. RESULTS: On MR images, 24 of 26 tendons showed signal abnormalities, and 19 of 26 were enlarged. Abnormal signal was a diffuse stippled pattern with many low-signal round structures of equal size surrounded by high-signal material on all pulse sequences. Abnormal signal was seen in tendons of both normal and abnormal size. Bilateral and symmetric changes were found in all but one patient. Tendinopathy in patients without known hyperlipidemia appeared indistinguishable from tendon xanthomas in six (29%) of 21 tendons. The other tendons (71%) were distinctly different from xanthomas without a uniform stippled signal pattern. CONCLUSION: MR imaging of patients with familial hyperlipidemia showed an abnormal stippled signal pattern with or without enlargement or abnormal configuration of the tendon. MR imaging is a more sensitive method than physical examination and plain films for detecting abnormalities in Achilles tendons of patients with hyperlipidemia. Although the MR signal pattern of xanthomas is often different from that of partial tendon tears, tendon degeneration, or tendinitis, a significant overlap in appearance can be observed and the MR appearance of a xanthoma is not pathognomonic.
Technical improvements in MR imaging have resulted in the ability to detect soft tissue and bone pathology, with great facility in the elbow joint. This allows application of MRI to the elbow in the same valuable ways it has been used in other joints for a much longer period.
Careful analysis of conventional radiographs remains the first step in the investigation of intra-articular abnormalities. However, other imaging techniques, such as ultrasonography, arthrography, computed tomography and magnetic resonance imaging, may add critical information that allows the correct diagnosis. The authors discuss the evaluation of masses within a joint on the basis of plain film analysis, as well as the contribution of additional imaging techniques to the differential diagnosis.
This article reviews the numerous applications of ultrasound in the musculoskeletal system. Emphasis is made on the important and often under-utilized role of ultrasound in infections, vascular lesions, arthritis, and trauma.
Magnetic resonance imaging (MRI) is the technique of choice to depict normal anatomy and to image internal derangements of the knee. The overall accuracy of this method can reach approximately 94%. MRI can effectively replace diagnostic arthroscopy for evaluation of meniscal and ligamentous tears.
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One hundred consecutive magnetic resonance (MR) images of the knee in patients with acute complete anterior cruciate ligament (ACL) tears were reviewed to evaluate the prevalence and patterns of associated occult fractures. Eighty-nine occult fractures were identified in 56 knees. All occult fractures were in the posterior aspect of the lateral tibial plateau. Of these, occult fractures were isolated in 24 cases (43%) and were in combination with fractures in the middle aspect of the lateral femoral condyle in 26 (46%), with fractures in the posterior aspect of the medial tibial plateau in four (7%), and with fractures involving all three areas in one (2%). Disruption of the ACL under valgus stress leads to anterior translation of the tibia and relative external rotation of the femur. This allows impaction of the posterior portion of the lateral tibial plateau against the middle of the lateral femoral condyle and accounts for the unique pattern of occult fractures associated with ACL tears. An occult fracture of the posterior lateral tibial plateau with or without an associated fracture in the lateral femoral condyle ("kissing contusion") is a relatively frequent finding in acute ACL tears and, when present, is highly suggestive of such an associated tear.
In 30 volunteers with normal shoulders, the following conclusions were made with regard to normal anatomic features at magnetic resonance (MR) imaging: (a) The supraspinatus tendon has low signal intensity, except for a 1-cm area with intermediate signal intensity in the region of the "critical zone." (b) The deltoid tendon attachment on the inferior surface of the acromion may simulate a subacromial spur if not imaged in continuity. (c) Fluid in the long head of the biceps tendon sheath is normal if not completely surrounding the tendon. (d) The anterolateral branch of the anterior humeral circumflex vessels in the proximal bicipital groove adjacent to the biceps tendon mimics fluid in the tendon sheath. (e) Continuity or obliteration of the subacromial-subdeltoid bursal fat plane is an unreliable diagnostic sign since the fat plane is often focally absent. (f) Fluid is not detected in subacromial-subdeltoid bursae. (g) Undercutting of the anterior glenoid labrum by hyaline cartilage or a closely apposed middle glenohumeral ligament may simulate an anterior labral tear.