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Biomedical subjects

A A De Smet

Publications and source records attributed to A A De Smet.

At least 19 recordsLinked to original sources
PubMed2007

Classification and localization of acetabular labral tears.

OBJECTIVE: The purpose of this study was to compare the findings on hip MR arthrography (MRA) with the published MRA and arthroscopic classifications of hip labral tears and to evaluate a clock-face method for localizing hip labral tears. DESIGN/PATIENTS: We retrospectively reviewed 65 hip MRA studies with correlative hip arthroscopies. Each labrum was evaluated on MRA using the classification system of Czerny and an MRA modification of the Lage arthroscopic classification. In addition, each tear was localized on MRA by using a clock-face description where 6 o'clock was the transverse ligament and 3 o'clock was anterior. These MRA findings were then correlated with the arthroscopic findings using the clock-face method of localization and the Lage arthroscopic classification of labral tears. RESULTS: At MRA, there were 42 Czerny grade 2 and 23 grade 3 labral tears and 22 MRA Lage type 1, 11 type 2, 22 type 3 and 10 type 4 tears. At arthroscopy, there were 10 Lage type 1 flap tears, 20 Lage type 2 fibrillated tears, 18 Lage type 3 longitudinal peripheral tears and 17 Lage type 4 unstable tears. The Czerny MRA classification and the modified MRA Lage classification had borderline correlation with the arthroscopic Lage classification. Localization of the tears using a clock-face description was within 1 o'clock of the arthroscopic localization of the tears in 85% of the patients. CONCLUSIONS: The Lage classification, which is the only published arthroscopic classification system for hip labral tears, does not correlate well with the Czerny MRA or an MRA modification of the Lage classification. Using a clock-face description to localize tears provides a way to accurately localize a labral tear and define its extent.

Acetabulum↗
PubMed2001

Abnormal superior popliteomeniscal fascicle and posterior pericapsular edema: indirect MR imaging signs of a lateral meniscal tear.

OBJECTIVE: Because MR diagnosis of lateral meniscal tears can be difficult, indirect signs may be useful when a tear is suspected. We studied whether an abnormality of the superior popliteomeniscal fascicle or pericapsular edema was associated with lateral meniscal tears and thus may be an indirect MR imaging sign of a lateral meniscal tear. MATERIALS AND METHODS: We identified 59 consecutive patients who underwent both knee MR imaging examinations and knee arthroscopy. Thirty patients had lateral meniscal tears, and 29 had intact lateral menisci. We reviewed paired sagittal proton density- and T2-weighted MR images from these 59 patients for abnormal superior popliteomeniscal fascicles and edema surrounding the posterolateral capsule. RESULTS: The superior popliteomeniscal fascicles were abnormal in nine of the 30 patients with torn lateral menisci but were normal in all 29 patients with intact menisci (p = 0.001). Abnormal fascicles were apparent only when the lateral meniscal tear involved the posterior horn. Posterior pericapsular edema was seen in 10 patients with a torn posterior horn and in one patient with an anterior horn tear of the lateral meniscus, but in only two patients with intact menisci (p = 0.006). CONCLUSION: The presence of superior popliteomeniscal fascicle abnormalities and of posterior pericapsular edema is significantly associated with a tear of the lateral meniscus, most commonly in the posterior horn. Noting the presence of these findings may help improve the accuracy of MR diagnosis of lateral meniscal tears.

Adolescent↗
PubMed2000

Noninvasive evaluation before and after percutaneous therapy of iliac artery stenoses: the value of the Bernoulli-predicted pressure gradient.

PURPOSE: The purpose of this study was to assess the value of the Bernoulli-predicted pressure gradient in the noninvasive evaluation of patients undergoing iliac percutaneous transluminal angioplasty (PTA) or stent placement with the use of intra-arterial pressure measurements as the standard of reference. METHODS: Stent placement or PTA was performed in 261 patients with intermittent claudication caused by iliac artery stenoses (333 procedures). Intra-arterial translesional pressure gradients were recorded before and after each procedure. Hemodynamic success was defined as a postprocedural mean pressure gradient less than or equal to 10 mm Hg at rest and during vasodilatation. Before and after intervention, the following noninvasive parameters were determined: the Bernoulli-predicted pressure gradient, the peak systolic velocity ratio, and the ankle-brachial pressure index. RESULTS: Before treatment, both the intra-arterial-measured pressure gradients and the Bernoulli-predicted gradients indicated hemodynamic significance of the iliac artery stenoses. After treatment, both methods indicated significant improvement of the translesional pressure gradient (P <. 0001). However, the correlation between the intra-arterially measured pressure gradient and the Bernoulli-predicted gradient of iliac artery stenoses was low (Pearson's r = 0.27). None of the three investigated noninvasive methods could differentiate an optimal PTA or stent result from a suboptimal result, as assessed by intra-arterial pressure measurements. CONCLUSIONS: The disappointing correlation among the duplex velocity data, whether expressed as pressure gradient or as a peak systolic velocity ratio, and the actually measured pressure gradient might be caused by errors in pressure or velocity measurements or the different circumstances in which the pressure or velocity measurements were performed. Residual pressure gradients after iliac PTA or stent placement assessed with intra-arterial pressure measurements could not be assessed with the investigated noninvasive methods.

Angioplasty, Balloon↗
PubMed2000

Superior labrum anterior-posterior (SLAP) tears: evaluation of three MR signs on T2-weighted images.

PURPOSE: To compare the sensitivity and specificity of three magnetic resonance (MR) imaging signs for the diagnosis of superior labrum anterior-posterior (SLAP) tears. MATERIALS AND METHODS: The study involved 23 consecutive patients with a type 2, 3, or 4 SLAP tear at arthroscopy and 31 age-matched control patients with an arthroscopically normal or type 1 SLAP lesion. The superior labrum was evaluated on MR images for high signal intensity extending to the articular surface in the posterior third of the labrum, an irregular or laterally curved area of high signal intensity, or two high-signal-intensity lines. RESULTS: The sensitivity, specificity, and accuracy of posterior high signal intensity for a type 2, 3, or 4 SLAP tear were 48%, 94%, and 74%, respectively, for observer 1 and 61%, 81%, and 72%, respectively, for observer 2. For laterally curved area of high signal intensity, these values were 65%, 84%, and 76%, respectively, and 56%, 84%, and 72%, respectively. For two high-signal-intensity lines, these values were 17%, 94%, and 61%, respectively, and 13%, 94%, and 59%, respectively. For the presence of either posterior or laterally curved high signal intensity, the sensitivity was 65% for both observers, whereas the specificity was 84% for observer 1 and 74% for observer 2. The kappa values for interobserver agreement were 0.60 for posterior high signal intensity and 0.58 for laterally curved high signal intensity. CONCLUSION: Laterally curved and posterior high signal intensities are specific signs for distinguishing a SLAP tear from a normal-variant superior sublabral recess.

Adolescent↗
PubMed2000

MR imaging of the distribution and location of acute hamstring injuries in athletes.

OBJECTIVE: Although hamstring injuries are common in athletes, the distribution and location of such injuries have not been well defined. We used MR imaging to determine the frequency of injury by muscle, involvement of one or more muscles, and location of injuries within the musculotendinous unit. SUBJECTS AND METHODS: We performed MR imaging on 15 consecutive college athletes with clinically diagnosed acute hamstring injuries. A hamstring injury was diagnosed and located on MR imaging by identifying high signal intensity within the muscle on T2-weighted images. RESULTS: We found that 10 athletes had injuries of a single muscle with six injuries of the biceps femoris, three of the semitendinosus, and one of the semimembranosus. In an additional five athletes, we found primary injuries of the biceps femoris and secondary injuries of the semitendinosus. The injuries occurred in diverse locations within the muscles including five injuries at the proximal musculotendinous junction, two at the distal musculotendinous junction, four within the proximal half of the muscle belly, and four in the distal half. All eight intramuscular injuries were located at the musculotendinous junction within the muscle. CONCLUSION: The biceps femoris is the most commonly injured hamstring muscle and the semitendinosus is the second most commonly injured. Although hamstring injuries often involve one muscle injured proximally, multiple muscles were involved in 33% of athletes (5/15) and the injuries were distal in 40% of athletes (6/15). All intramuscular injuries occurred at the musculotendinous junction, either at the ends of the muscle or within the muscle belly.

Adult↗
PubMed2000

"Dem bones": osteochondral injuries of the knee.

MR imaging plays a valuable role in the diagnosis and staging of osteochondral injuries of the femorotibial joint. Bone contusions may be the source of a patient's pain, and MR imaging characteristics of certain types may help to predict which contusions might progress to more serious osteochondral lesions. MR imaging also is vital in the diagnosis of occult osteochondral fractures and in accurately classifying displaced intra-articular fractures. Although osteochondral dissecans usually is diagnosed radiographically, MR imaging is the best noninvasive test for determining if an osteochondral fragment is unstable. Unstable lesions are a treatable cause of knee pain.

Fractures, Spontaneous↗
PubMed1999

MR visualization of the popliteomeniscal fascicles.

OBJECTIVE: Although the popliteomeniscal fascicles are important stabilizers of the lateral meniscus, there have been few studies of their MR appearance. We wished to determine: (1) whether the fascicles are normally seen on MR imaging, and (2) whether certain imaging factors influenced their visualization. DESIGN AND PATIENTS: We reviewed the sagittal MR images of 66 consecutive patients who had no evidence of injury to the lateral compartment. We determined the frequencies of MR visualization of the superior and inferior popliteomeniscal fascicles, and whether visualization was affected by the weighting of spin echo sequences, the presence of a joint effusion, slice placement relative to the fascicles, and windowing of the images. RESULTS AND CONCLUSIONS: Both popliteomeniscal fascicles were seen in 64 of the 66 patients. The fascicles were better seen on T2-weighted images than on proton-density weighted images (P<0.01). On the T2-weighted images, fascicle visualization was not significantly affected by the presence or absence of an effusion, slice placement or image windowing (P=0.2 to 1.0). On proton-density weighted images, fascicle visualization was significantly improved when high-contrast windowing was used (P=0.04). In conclusion, we found that the popliteomeniscal fascicles are normally seen on MR imaging of the knee when there are no lateral compartment injuries. The fascicles are significantly better visualized on T2-weighted than on proton-density weighted images. Visualization is not significantly affected by the presence of an effusion or slice placement.

Humans↗
PubMed1999

Are oblique views needed for trauma radiography of the distal extremities?

OBJECTIVE: To our knowledge, few studies exist on the importance of the oblique view when radiography of the distal extremities is performed after acute trauma. Our prospective study aimed to determine whether the oblique view uniquely revealed abnormalities or clarified findings when it was obtained along with routine frontal and lateral radiographs. SUBJECTS AND METHODS: We prospectively interpreted 1461 consecutive radiographic examinations of the distal extremities in patients presenting with acute trauma to four family medicine clinics. The anatomic sites radiographed included the ankle, foot, toe, wrist, hand, finger, and thumb. Each study was interpreted and given a diagnostic certainty score using the lateral and posteroanterior or anteroposterior views only and then scored again with the oblique view added. RESULTS: The examinations included 421 with abnormal findings, 34 with equivocal findings, and 1006 with normal findings. The addition of the oblique view changed the interpretation in 70 (4.8%) of the 1461 examinations. Of these changed interpretations, 39 were changed from equivocal to either positive or negative, three from positive to negative, and 28 from negative to positive. Addition of the oblique view increased diagnostic confidence: The percentage of examinations scored as having probably normal, equivocal, and probably abnormal findings decreased from 13.9% with two views to 8.4% with three views (p < .0001). The oblique view was equally valuable in the ankle, foot, toe, wrist, hand, finger, and thumb. CONCLUSION: In the distal extremities, the oblique view uniquely reveals abnormalities and increases the confidence of the final radiographic diagnosis when the oblique view is interpreted along with frontal and lateral radiographs.

Adolescent↗
PubMed1998

The hypothenar hammer syndrome: update and literature review.

The hypothenar hammer syndrome is a rather rare vascular injury. It is seen in posttraumatic digital ischaemia caused by irregularity or occlusion of the distal ulnar artery at the level of the hamate bone. It characteristically occurs in the dominant hand of middle-aged men whose occupational or recreational activities require the use of the hand as a hammer. Three typical cases are presented along with literature review. The different aspects of this syndrome are described such as the cause and pathogenesis, the most important clinical characteristics and differential diagnosis, the role of angiography and Doppler mapping in establishing the diagnosis and the various therapeutic options, ranging from conservative treatment to resection of the thrombosed artery segment with vein graft interposition.

Adult↗
PubMed1997

Anteroinferior tears of the glenoid labrum: fat-suppressed fast spin-echo T2 versus gradient-recalled echo MR images.

OBJECTIVE: To compare fat-suppressed fast spin-echo (FSE) T2-weighted images with gradient-recalled echo (GRE) T2*-weighted images in the evaluation of anteroinferior labral tears. DESIGN: MR images were retrospectively reviewed by two radiologists masked to the history and arthroscopic findings. They separately interpreted the anteroinferior labrum as torn or intact, first on one pulse sequence and then, 4 weeks later, on the other sequence. The MR interpretations were correlated with the arthroscopic findings. PATIENTS: Nine patients with anteroinferior labral tears, and nine similarly-aged patients with normal, labra were studied. RESULTS AND CONCLUSIONS: Observer 1 had a sensitivity of 0.56 on the GRE images and 0.67 on the FSE images (P > 0.5), with a specificity of 1.0 for both sequences. Observer 2 had a sensitivity of 0.78 and a specificity of 0.89 for both sequences. In this small study there is no significant difference between GRE and fat-suppressed FSE images in their ability to diagnose anteroinferior labral tears. When evaluating the labrum with conventional MRI, axial fat-suppressed FSE T2-weighted images can be used in place of GRE images without a loss of accuracy.

Adolescent↗
PubMed1997

Untreated osteochondritis dissecans of the femoral condyles: prediction of patient outcome using radiographic and MR findings.

OBJECTIVE: We investigated the usefulness of plain film and MR findings in predicting the outcome of conservatively treated patients with femoral osteochondritis dissecans. DESIGN: Without knowledge of the clinical outcome, we retrospectively reviewed the initial plain films and MR examinations. Each MR examination was evaluated for the four MR findings of instability. PATIENTS: Fourteen patients were studied in whom osteochondritis dissecans of a femoral condyle had been treated conservatively for periods ranging from 1.2 to 8.5 years. RESULTS AND CONCLUSION: Three of five patients with an open femoral growth plate and one of nine patients with a closed growth plate had a good clinical outcome. Both patients with lesions smaller than 160 mm2 in area had a good outcome and ten of 12 patients with larger lesions had a poor outcome. Both patients with stable lesions by MR imaging had a good outcome while ten of 12 patients with a lesion unstable by MR imaging had poor outcomes. All six patients with a cartilage fracture or articular defect had poor outcomes. The results of this study should be considered preliminary since only 14 patients were followed. However, it appears that a good clinical outcome is likely when the femoral growth plate is open, when the osteochondritis dissecans is small, and when the lesion is stable by MR imaging. When a cartilage fracture or articular defect is found on MR imaging, the patient is likely to have a poor outcome.

Adolescent↗
PubMed1996

Reassessment of the MR criteria for stability of osteochondritis dissecans in the knee and ankle.

OBJECTIVE: T2-weighted MR images has been reported to be an accurate method for assessing osteochondritis dissecans. We reviewed our MR experience to confirm the accuracy of the published criteria of instability. We also assessed the value of each of four MR signs of instability. DESIGN: We reviewed the original MR interpretations, arthroscopic reports, and MR examinations of 40 patients with osteochondritis dissecans of the talar dome or femoral condyles. Arthroscopy was used as the gold standard for stability. The MR examinations were reviewed retrospectively for a high-signal-intensity line or cystic area beneath the lesion, a high-signal-intensity line through the articular cartilage, or a focal articular defect. PATIENTS: All patients who had undergone MR imaging for osteochondritis dissecans from 1990 to 1993 were reviewed. Forty patients were identified who had arthroscopy after the MR examination. There were 30 male and 10 female patients with an average age of 25.7 years. Thirty-one lesions were in femoral condyle and nine were in the talar dome. RESULTS AND CONCLUSIONS: The original MR interpretations correctly identified 35 of the 36 unstable lesions and all 4 stable lesions, giving a sensitivity of 0.97 and specificity of 1.0. There was a 98% agreement between the original and retrospective diagnoses. A high-signal-intensity line was seen beneath 72% of the 36 unstable lesions. The other three signs were noted in 22-31% of the unstable lesions. Fifty-six percent of the unstable lesions showed only one sign of instability. MR imaging is a highly sensitive method for detection of unstable osteochondritis dissecans. The presence of any one sign indicates instability, the most frequent sign being an underlying high-signal-intensity line. Because we examined only four stable lesions, our 95% confidence interval of 0.40-1.0 for a specificity of 1.0 gives only a limited estimate of the specificity of MR.

Adult↗
PubMed1996

MR of the postoperative knee.

There have been multiple recent refinements in the arthroscopic techniques of meniscal surgery and anterior cruciate ligament (ACL) reconstruction, and these are now allowing many postoperative patients to resume an active lifestyle. A result is an increasing number of postoperative patients who are referred for a magnetic resonance (MR) scan of the knee because of a recurrent injury. In this article, we will discuss some of the MR findings of retorn menisci and the role of MR arthrography. We will also review the changes that occur in the MR appearance of the ACL graft during the first year after surgery, and its effect on the accuracy of diagnosing graft tears. The MR findings after other less common knee procedures will also be described.

Anterior Cruciate Ligament↗