Biomedical subjects

R G Dussault

Publications and source records attributed to R G Dussault.

At least 19 recordsLinked to original sources

PubMed1999

Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips.

To determine whether fatty marrow conversion of the proximal femoral metaphysis is related to osteonecrosis of the femoral head using a marrow conversion index ([signal intensity of the proximal femoral metaphysis/signal intensity of the greater trochanter] x 100 in T1 weighted magnetic resonance images), a case control study was conducted on 42 osteonecrotic hips in 28 patients. The 28 patients (42 osteonecrotic hips) were matched with 84 control patients (84 normal hips) for gender, age (5-year range), and time of presentation (1-year range). The marrow conversion index was measured in each hip studied. The index was 90.2% (standard deviation, 8.2%) in osteonecrotic hips and 75.1% (standard deviation, 9.1%) in matched controls. By conditional logistic regression, a 5% increase in the index was associated with 3.6 times increase of the odds ratio of osteonecrosis and a 10% increase with a 12.9 times increase of the odds ratio. The marrow conversion index, which reflects the ratio of fatty marrow conversion of the proximal femoral metaphysis to that of the greater trochanter measured on T1 weighted magnetic resonance images, is increased in osteonecrotic hips.

Adipose Tissue↗

PubMed1999

Muscle infarction in patients with diabetes mellitus: MR imaging findings.

PURPOSE: To describe the magnetic resonance (MR) imaging findings in diabetic patients with muscle infarction and to describe commonly associated clinical features. MATERIALS AND METHODS: The MR imaging studies of 21 patients with diabetic muscle infarction were reviewed retrospectively. Of the 21 patients, 12 were women, and nine were men; the mean age was 48 years (range, 30-77 years). RESULTS: Eight patients had bilateral lower-extremity involvement; six had involvement confined to the right lower extremity and seven to the left. The thigh was involved in 17 patients (81%). One or more of the musculi vastus, the most frequently affected muscle group, were affected in 16 patients (76%). Four patients (19%) had isolated calf involvement. MR imaging studies showed diffuse enlargement of involved muscle groups and partial loss of normal fatty intermuscular septa. MR imaging also allowed identification of areas of subfascial fluid in 16 patients (76%) and subcutaneous edema in 19 patients (90%). MR imaging showed involved muscle groups best with T2-weighted, inversion-recovery, and gadolinium-enhanced sequences, where the infarcted muscles appeared diffusely hyperintense compared with adjacent muscles. Comparison of T2-weighted and gadolinium-enhanced MR images of nine patients showed enlarged, enhancing muscles in all patients and small, focal, rim-enhancing fluid collections in six of nine patients (66%). CONCLUSION: Diabetic muscle infarction is suggested in diabetic patients with sudden onset of severe pain in the thigh or calf muscles who have MR imaging findings of diffuse edema and swelling of multiple thigh and calf muscles (often in more than one compartment).

Diabetes Mellitus, Type 1↗

PubMed1998

Anatomy and clinical significance of the horizontal cleft in the infrapatellar fat pad of the knee: MR imaging.

OBJECTIVE: The purpose of this study was to determine the prevalence and nature of a horizontal cleft in the posterior aspect of Hoffa's infrapatellar fat pad and to show pathologic processes involving this cleft. MATERIALS AND METHODS: Fifty consecutive MR imaging examinations of the knee were evaluated for the presence and appearance of a cleft in the infrapatellar fat pad. Examples of abnormalities involving the cleft were collected from additional MR studies. MR imaging, gross dissection, and histologic examination of a cadaveric knee were also performed to evaluate the anatomy and histology of the cleft. RESULTS: The cleft in the infrapatellar fat pad was revealed on MR imaging in 45 of 50 knees and had a variable shape, either linear (82%), pipe-shaped (7%), or globular-shaped (11%). Joint effusion or anterior cruciate ligament tear did not affect the appearance of the cleft. The cleft was located anterior to the distal insertion of the anterior cruciate ligament on the tibia. At gross dissection of the cadaveric knee, the roof of the cleft was formed by the ligamentum mucosum (infrapatellar plica), and the cleft was lined with synovium. The prospective evaluation of additional MR imaging examinations of the knee revealed pathologic entities of the cleft such as ganglion cysts, loose bodies, nodular synovitis, and amyloid. CONCLUSION: A horizontal cleft located in the posterior aspect of the infrapatellar fat pad is a common and normal MR imaging finding with a prevalence of 90%. The horizontal cleft is lined with synovium and its roof is formed by the ligamentum mucosum (infrapatellar plica). This cleft communicates with the knee joint. A distended cleft can form a prominent recess mimicking pathologic processes; conversely, disorders can arise in the cleft.

Adipose Tissue↗

PubMed1997

Radiographic measurements of dysplastic adult hips.

Hip dysplasia is a not uncommon feature in adults and can vary from subtle acetabular dysplasia to complex sequelae of developmental dysplasia of the hip. This review article describes the most useful radiographic measurements used to evaluate the adult hip. The frontal projection of the pelvis permits measurement of the center-edge angle (CE angle) and "horizontal toit externe" angle (HTE angle), both of which assess the superior coverage of the acetabulum. The femoral neck-shaft angle (NSA) is also measured on this view. The false profile radiograph of the pelvis is described. It allows measurement of the vertical-center-anterior angle (VCA angle), which determines the anterior acetabular coverage and detects early degenerative hip joint disease. When surgery is contemplated, computed tomography (CT) is useful to better determine the anterior acetabular coverage by use of the anterior acetabular sector angle (AASA), and the posterior acetabular coverage by use of the posterior acetabular sector angle (PASA). CT also permits measurement of femoral anteversion. These measurements are particularly useful in the evaluation of acetabular dysplasia and for the preoperative assessment of the dysplastic hip.

Adult↗

PubMed1997

Plain film evaluation of degenerative disk disease at the lumbosacral junction.

OBJECTIVE: Diagnosing degenerative disk disease (DDD) at the lumbosacral junction (LSJ) on plain films is often difficult, compared with other disk levels. The purpose of this study was to determine whether criteria for diagnosis of DDD at the LSJ can be established for plain films. DESIGN AND PATIENTS: We retrospectively reviewed 100 lumbar MRI scans of patients who also had lumbar plain films. Using MRI as the reference standard, the LSJ was classified as normal (n=35) or exhibiting mild (n=45) or severe (n=20) DDD by two radiologists using accepted criteria. Measurements were performed on the plain films by two other radiologists and the average measurements were tabulated according to the three categories of DDD defined by MRI. Plain film measurements included the anterior and posterior disk heights (ADH, PDH), Farfan's ratio, determined by adding ADH to PDH and dividing that number by the measured anteroposterior (AP) length of the inferior end plate of L5 [(ADH+PDH)/AP length of L5], and lumbosacral angle (LSA). Subsequently, five additional radiologists interpreted the radiographs by visual inspection only, for DDD at the LSJ, both before and, several weeks later, after being provided with the quantitative data for normal versus DDD. RESULTS AND CONCLUSION: There was a statistically significant difference between normal disk and increasing severity of DDD on radiographs using the parameters of PDH and Farfan's ratio. There was no statistically significant difference regarding ADH or LSA. Diagnostic accuracy by visual inspection was not significantly altered using the quantitative data for interpretation of DDD (68% correct before, 69.5% correct after). Analysis of results indicates that PDH is the most reliable and easily used criterion for detection of DDD at the LSJ. A PDH < or =5.4 mm on plain lateral film indicates DDD; PDH > or =7.7 mm indicates the absence of DDD on plain film.

Adult↗

PubMed1997

Acute knee trauma: how many plain film views are necessary for the initial examination?

OBJECTIVE: To determine whether anteroposterior (AP) and lateral views of the knee are equivalent to four views in acute fracture detection. DESIGN: Three musculoskeletal radiologists retrospectively interpreted the plain film knee examinations of each patient, establishing ground truth for the presence or absence of a fracture. Cases were presented to four masked senior radiology residents twice--once as a two-view study and again as a four-view study--with 4 weeks separating the two reading sessions to minimize recall bias. Sensitivity, specificity, and diagnostic performance were calculated. PATIENTS: Ninety-two patients presenting to the emergency department with acute knee trauma were evaluated with at least a four-view plain film examination. RESULTS AND CONCLUSIONS: Mean sensitivity for fracture detection using four views (85%) was significantly higher than that using two views (79%). Mean specificity and receiver operating characteristic curve areas were not significantly different using two or four views. Four views are more sensitive than AP and lateral views alone in detection of acute knee fracture.

Acute Disease↗

PubMed1997

Imaging of the knee. Current status.

This article reviews the variety of imaging modalities that are currently being used to evaluate the knee. Nuclear scintigraphy is discussed with emphasis on prosthesis abnormalities. Sonography is discussed with regard to the evaluation of popliteal masses. The uses of computed tomography, especially in the evaluation of the tibial plateau fracture, are discussed, and the role of fluoroscopy, computed tomography, and sonography in image-guided needle procedures are reviewed. Emphasis is placed on the role of MR imaging in knee imaging, with attention to internal derangements, bursal and capsular pathology, and other assorted intra- and extra-articular disorders. The focus of this article is to review the wealth of information that may be obtained by using these imaging modalities.

Arthrography↗

PubMed1997

Fluoroscopically guided injections into the foot and ankle: localization of the source of pain as a guide to treatment--prospective study.

PURPOSE: To determine the value of injections of local anesthetic and steroids in the foot and ankle in localizing the source of pain and their effect on clinical confidence and decision making. MATERIALS AND METHODS: In 47 patients, fluoroscopically guided injections of local anesthetic and steroid into the foot and ankle were performed in 106 intra- and extraarticular sites. Questionnaires were completed by the referring surgeon before and after injections to evaluate the level of confidence with regard to the source of pain for each site injected and the proposed treatment plan. RESULTS: Forty-three (91%) patients reported pain relief after injections. The level of confidence that the site injected was the source of pain increased in 68 (64%) sites, decreased in 19 (18%) sites, and remained unaltered in 19 (18%) sites (P < .01). The treatment plan was changed from nonsurgical initially to surgical in three (8%) of 36 patients and was changed from surgical to nonsurgical in three (27%) of 11 patients after injections. Of the remaining eight patients, treatment was altered in three (37%) as a result of pain relief after the injections. CONCLUSION: Fluoroscopically guided injections of local anesthetic and steroid in the foot and ankle can improve clinical confidence with regard to the site of pain and may be valuable in clinical decision making and patient treatment.

Adult↗

PubMed1997

Acutely injured knee: effect of MR imaging on diagnostic and therapeutic decisions.

PURPOSE: To assess the effect of knee magnetic resonance (MR) imaging on the diagnosis and management of acute knee injury. MATERIALS AND METHODS: Two orthopedic knee surgeons prospectively completed pre- and post-MR imaging questionnaires on 84 of 91 consecutive patients with acute knee injury. The pre- and post-MR imaging clinical diagnoses, certainty regarding these diagnoses, other diagnostic tests, and subjective impression of the usefulness of MR imaging were determined. RESULTS: Seven hundred thirty-one of 840 pre- and post-MR imaging diagnoses agreed. Agreement was lowest for medial meniscal injuries (54 of 84). Significantly fewer meniscal injuries were suspected after MR imaging (P < .05). In 60 patients, the orthopedist changed at least one of the 10 potential diagnoses after MR imaging. Clinical diagnostic certainty increased by a mean of 14% for all diagnoses. The increase in diagnostic certainty was greatest for medial meniscal injuries (30%), followed by lateral meniscal injuries (21%). The proposed management changed in 41 patients, resulting in significantly fewer arthroscopic procedures (P < .01). The post-MR imaging management plans included 37% (27 of 73) fewer arthroscopic procedures. CONCLUSION: MR imaging affects the diagnosis and management of acute knee injury by decreasing the number of arthroscopic procedures, improving clinician diagnostic certainty, and assisting in management decisions.

Acute Disease↗

PubMed1997

MR imaging of ligamentous abnormalities of the elbow.

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.

Adolescent↗

PubMed1996

Imaging of bursae around the shoulder joint.

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.

Bursa, Synovial↗

PubMed1996

The impact of ankle radiographs on the diagnosis and management of acute ankle injuries.

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.

Acute Disease↗

PubMed1996

Lateral-compartment bone contusions in adolescents with intact anterior cruciate ligaments.

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.

Adolescent↗

PubMed1996