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Biomedical subjects

J V Crues

Publications and source records attributed to J V Crues.

At least 37 records · Page 2Linked to original sources
PubMed1993

Saline magnetic resonance arthrography in the evaluation of glenohumeral instability.

Sixty-five patients underwent magnetic resonance (MR) shoulder arthrography. Forty-eight of these patients underwent examination under anesthesia (EUA). MR images were retrospectively evaluated for signs felt to be imaging indicators of shoulder instability, including evaluation of various capsular measurements and the presence of glenoid labral tears, as well as Hill-Sachs fractures. Statistical analysis of the results showed that no correlation between capsular indicators with EUA-documented instability was found. However, there was a statistically significant correlation between the presence of a Bankart cartilaginous deformity (p = 0.000) and Hill-Sachs fractures (p = 0.022) with EUA-documented instability. Sensitivity to labral tears was 89% and specificity was 98%, whereas Hill-Sachs fracture detection was 69% and 87%, respectively. We believe that MR saline arthrography is of benefit in the evaluation of the anterior labrum when unenhanced MR imaging is inconclusive, and we speculate on the role of MR arthrography as a primary investigative tool.

Adolescent↗
PubMed1993

Magnetic resonance arthrography of the shoulder.

Recently, there have been attempts to improve the accuracy of MR imaging by distending the glenohumeral joint with fluid prior to imaging. This article reviews the techniques employed in performing MR arthrography, imaging characteristics of MR arthrography, and diagnostic use of the procedure.

Contrast Media↗
PubMed1993

Pathogenesis of rotator cuff disorders. Magnetic resonance imaging characteristics.

In summary, rotator cuff pathology is a continuum that begins with degeneration of collagen fibers at a rate that exceeds that of repair. The degenerative process is accelerated with aging, chronic inflammatory diseases, impingement, and repetitive activity. A tendon weakened by disease may then be torn by routine physical activity. MR imaging can help predict which patients are at risk for rotator cuff disease because of abnormal anatomy and can detect the disease at an early stage so that the progression may be altered before a tear occurs.

Humans↗
PubMed1992

MR imaging in the evaluation of SLAP injuries of the shoulder: findings in 10 patients.

OBJECTIVE: Injuries to the superior portion of the glenoid labrum, called SLAP (superior labrum, anterior and posterior) injuries, are recently recognized injuries consisting of tears of the long head of the biceps tendon anchor/superior labral complex. The purpose of this study was to determine if the MR imaging findings in patients with surgically proved SLAP injuries correspond to the abnormalities found at arthroscopy. MATERIALS AND METHODS: Four variants of SLAP lesions have been described; they are based on the degree of compromise of the superior portion of the glenoid labrum, biceps tendon, and labral-biceps anchor. A type I lesion has superior labral fraying in the region of the biceps anchor. A type II lesion has superior labral fraying and stripping of the superior part of the glenoid labrum and attached biceps off the underlying glenoid fossa. A type III lesion has a bucket-handle tear of the superior portion of the glenoid labrum in the region of the biceps anchor. A type IV lesion has a bucket-handle tear of the superior part of the glenoid labrum with extension of the tear into the proximal biceps tendon. Standard spin-echo MR imaging studies in 10 patients with surgically proved SLAP lesions were evaluated retrospectively. Correlations were made between MR imaging findings and the SLAP injury type determined from descriptions in the surgical report. MR imaging studies in a control group of seven symptomatic patients surgically proved not to have SLAP injuries also were evaluated. RESULTS: MR imaging examinations of two patients with type I lesions showed irregularity of the labral contour and a slight increase in signal intensity on all imaging sequences. MR imaging examinations of two patients with type II lesions showed globular high signal interposed between the superior part of the glenoid labrum and the superior portion of the glenoid fossa. One case showed high signal in the labral-biceps anchor. The other case showed paired cleavages in the superior and inferior aspects of the superior part of the glenoid labrum at the labral-biceps anchor. MR imaging examinations of two patients with type III lesions showed superior labral tears identified as high signal intensity within the superior part of the labrum separate from the normal superior part of the labral cavity. MR imaging examinations of the four patients with type IV lesions showed diffuse high signal intensity within the superior part of the glenoid labrum with marked abnormal high signal intensity extending into the proximal high signal intensity within the superior part of the labrum separate from the normal superior part of the labral cavity. MR imaging examinations of the four patients with type IV lesions showed diffuse high signal intensity within the superior part of the glenoid labrum with marked abnormal high signal intensity extending into the proximal biceps tendon. None of the MR imaging studies of patients in the control group showed findings seen on MR imaging studies of patients with surgically proved SLAP lesions. CONCLUSION: Although prospective data are required to document accuracy, these preliminary data suggest that an MR examination can be useful in detecting SLAP abnormalities and establishing the type of SLAP lesion before surgery, thereby permitting better operative planning.

Adult↗
PubMed1992

Magnetic resonance imaging of the knee: evaluation of meniscal disease.

The advent of MR imaging in musculoskeletal radiology, coupled with advances in the past decade in the treatment of knee disorders, has fueled an explosion of interest in MR imaging of the knee. Evaluation of meniscal pathology has been central to this development. The accuracy of MR imaging in the diagnosis of meniscal tears is now well established; attention has more recently been focused on the prevalence, natural history, and clinical significance of other intrameniscal signal abnormalities, as well as on the postoperative meniscus. Nonmeniscal knee disorders that may clinically mimic meniscal lesions are also reliably diagnosed with MR imaging. Technical advances in pulse sequences allow knee imaging with enhanced accuracy and efficiency.

Humans↗
PubMed1992

Magnetic resonance imaging of reconstructed knee ligaments.

Reconstruction of knee ligaments is now a common orthopedic procedure. Patients are frequently referred for magnetic resonance imaging (MRI) after later reinjury, and the ability to recognize normal reconstructed knee ligaments is therefore becoming increasingly important. This pictorial essay demonstrates various reconstructions of the cruciate and the collateral ligaments, as well as several abnormalities of these ligaments.

Anterior Cruciate Ligament↗
PubMed1991

Magnetic resonance imaging of shoulder impingement.

MRI is an accurate technique for diagnostic evaluation of a broad spectrum of shoulder pathology. In particular, rotator cuff injuries are a frequent cause of pain and disability. The mechanism of injury to the supraspinatus tendon usually begins with microscopic tears of fibers of the triple helix collagen molecule. This leads to increased motion of the bound water within the collagen molecule that lengthens the effective T2 of the tendon, allowing short TE imaging sequences to detect signal in abnormal tendons. Clinically significant disease probably does not occur without frank collagen rupture, and the associated collection of free water within the severely diseased tendon presents as high signal on long TE images. Thus, the clinical significance of tendon disease is best evaluated on long TR, long TE image acquisitions. Any process that accelerates microscopic tear formation or delays repair can increase a patient's risk of supraspinatus tendon tears. Impingement is the most important process accelerating microscopic tear formation. MRI's multiplanar, tomographic imaging ability markedly improves the ability to sensitively and specifically detect bony impingement. Hopefully, this will allow earlier arthroscopic decompression and improved patient prognosis with impingement.

Athletic Injuries↗
PubMed1990

Meniscal pathology. The expanding role of magnetic resonance imaging.

Magnetic resonance imaging (MRI) is a recently developed diagnostic medical imaging technology that shows great promise in the evaluation of knee meniscal diseases. Fifty-seven patient knees were evaluated by a single experienced MRI interpreter; the findings were compared with arthroscopic findings by a single experienced knee arthroscopist. The overall sensitivity and specificity rates of MRI for tears in virgin menisci compared to arthroscopy were both 92%. These results support reports in the literature that MRI is an accurate noninvasive technique for evaluating meniscal tears. Seven patients were treated with arthroscopic meniscal repair and were evaluated by MRI before and after surgery. Despite an asymptomatic postoperative status in six patients, abnormal intrameniscal signal persisted in four. An unstable meniscal fragment was visualized in the patient with postoperative pain. MRI is also useful in evaluating meniscal degeneration, meniscal ossicles, parameniscal cysts, and abnormal meniscal morphology. MRI is the noninvasive diagnostic technique of choice in evaluating a spectrum of knee meniscal diseases.

Adolescent↗
PubMed1989

Exposure to a 1.5-T static magnetic field does not alter body and skin temperatures in man.

The literature has conflicting reports concerning the effect of static magnetic fields on body and skin temperatures in mammals. Since temperature changes induced by static magnetic fields would have important safety implications for clinical magnetic resonance imaging body (sublingual pocket) and skin (abdomen, forehead, chest, upper arm, forearm, thigh, and calf) temperatures were determined in six normal subjects using a fluoroptic thermometry system during a 20-min exposure to a 1.5-T static magnetic field. Ambient conditions were controlled and held constant. An analysis of variance for repeated measures revealed that there were no statistically significant changes in body or any of the skin temperatures recorded. We conclude that exposure for 20 min to a 1.5-T static magnetic field does not alter body and skin temperatures in man.

Air Movements↗
PubMed1989

Quantification of left ventricular myocardial mass in humans by nuclear magnetic resonance imaging.

The ability of NMRI to assess LV mass was studied in 20 normal males. By means of a 1.5 Tesla GE superconducting magnet and a standard spin-echo pulse sequence, multiple gated short-axis and axial slices of the entire left ventricle were obtained. LV mass was determined by Simpson's rule with the use of a previous experimentally validated method. The weight of the LV apex (subject to partial volume effect in the short-axis images) was derived from axial slices and that of the remaining left ventricle from short-axis slices. The weight of each slice was calculated by multiplying the planimetered surface area of the LV myocardium by slice thickness and by myocardial specific gravity (1.05). Mean +/- standard deviation of LV mass and LV mass index were 146 +/- 23.1 gm (range 92.3 to 190.4 gm) and 78.4 +/- 7.8 gm/m2 (range 57.7 to 89.4 gm/m2), respectively. Interobserver agreement as assessed by ICC was high for determining 161 individual slice masses (ICC = 0.99) and for total LV mass (ICC = 0.97). Intraobserver agreement for total LV mass was also high (ICC = 0.96). NMRI-determined LV mass correlated with body surface area: LV mass = 55 + 108 body surface area, r = 0.83; with body weight: LV mass = 26 + 0.77 body weight, r = 0.82; and with body height: LV mass = 262 +/- 5.9 body height, r = 0.75. Normal limits were developed for these relationships. NMRI-determined LV mass as related to body weight was in agreement with normal limits derived from autopsy literature data.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

MRI of the knee in diffuse pigmented villonodular synovitis.

Magnetic resonance imaging (MRI) was performed on 11 patients with surgically proven pigmented villonodular synovitis (PVNS) of the knee. PVNS was diagnosed on the basis of presence of hemosiderin, joint effusion, and hyperplastic synovium without significant joint destruction. MRI provided a detailed map of the distribution of the disease within the joint, emphasizing the common occurrence of the disease behind the cruciate ligaments and in synovial cysts in the popliteal fossa. MRI aided in preoperative planning and postoperative follow-up for residual and recurrent disease. Nine additional cases of joint hemorrhage, hemophilia, desmoplastic tumors, and synovial chondromatosis were included to delineate differential diagnostic criteria.

Adult↗
PubMed1989

Bone abnormalities of the knee: prevalence and significance at MR imaging.

Focal abnormal signal intensity within the distal femoral condyles or proximal tibial plateaus is frequently seen on T1- or intermediate-weighted magnetic resonance (MR) images of the knee. To characterize the prevalence and significance of these findings better, a retrospective study of MR imaging of the knee, performed on the first 434 consecutive patients at a primarily outpatient community MR imaging center, was undertaken. A signal intensity loss demonstrated on images with a short echo time (20 or 25 msec) was divided into three types based on morphologic criteria. A type 1 finding was a diffuse, often reticulated signal intensity loss in the metaphyseal and epiphyseal regions of bone. A type 2 loss was associated with an interruption in the smooth, black cortical line. A type 3 finding was a profound signal intensity loss primarily restricted to the immediate subcortical region. Seventeen percent of all cases revealed a type 1 or 2 loss that may have been compatible with acute bone injuries. These bone lesions were frequently associated with tears of the anterior cruciate ligament and contralateral collateral ligament, but infrequently these lesions were detected with plain radiography and arthroscopy. When associated with a weight-bearing cortex, bone injuries detected with MR imaging may explain clinical symptoms of pain on weight bearing, and type 1 injuries may represent regions of bone at increased risk for the subsequent development of insufficiency fractures if the bone is not adequately protected during trabecular healing.

Adolescent↗
PubMed1989

Alterations in body and skin temperatures caused by magnetic resonance imaging: is the recommended exposure for radiofrequency radiation too conservative?

Increases in tissue temperature caused by exposure to radiofrequency (RF) radiation are a primary safety concern of magnetic resonance imaging (MRI). Therefore, body and skin temperatures were measured in six subjects before (20 min), during (30 min) and after (20 min) MRI procedures performed at specific absorption rates (SARs) six to 10 times higher than the limit recommended by the UK National Radiological Protection Board. Body temperature was unchanged throughout the experiment. Abdominal skin temperature increased significantly (p less than 0.05) during MRI, decreased significantly post-MRI, but was still significantly (p less than 0.05) higher than baseline. The highest abdominal skin temperature recorded was 36 degrees C. Upper arm, forearm and chest skin temperatures increased significantly (p less than 0.05) during MRI and remained elevated post-MRI. The highest skin temperatures recorded on the upper arm, forearm and chest were 38.1, 36.0 and 34.5 degrees C, respectively. Thigh and calf skin temperatures were not significantly changed during MRI. These alterations in tissue temperatures were physiologically trivial and easily tolerated by the subjects, suggesting that the recommended exposure to RF radiation during MRI of the body for patients with normal thermoregulatory function may be too conservative.

Abdomen↗
PubMed1988

Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure.

Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.

Acute Kidney Injury↗