Biomedical subjects

J M Burk

Publications and source records attributed to J M Burk.

4 recordsLinked to original sources

PubMed1990

Acute experimental osteomyelitis and abscesses: detection with MR imaging versus CT.

Acute experimental osteomyelitis and abscesses were induced in the proximal tibia and surrounding soft tissues, respectively, in 67 New Zealand white rabbits. Fifty-three rabbits were injected with a Staphylococcus aureus solution and 26, with sterile saline in tibial medullae and/or surrounding soft tissues. Contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging were performed 7 days after inoculation. Immediately after imaging, the animals were killed and necropsy was performed. MR imaging was more sensitive than CT in the detection of osteomyelitis (94% vs 66%, P less than .025) and abscesses (97% vs 52%, P less than .001). MR imaging was equally specific as CT in the exclusion of osteomyelitis (93% vs 97%, chi 2 = 0) but less specific than CT in the exclusion of abscesses (77% vs 100%, P less than .025). The overall accuracy of MR imaging was somewhat, although not significantly, greater than that of CT in the detection of both osteomyelitis (93% vs 80%) and abscesses (87% vs 75%).

Abscess↗

PubMed1988

Femoral head avascular necrosis: MR imaging with clinical-pathologic and radionuclide correlation.

A retrospective evaluation of magnetic resonance (MR) imaging for the detection of avascular necrosis (AVN) of the femoral head was performed in 49 patients (85 hips) with clinical suspicion of AVN. Positive findings at bone biopsy or evidence on plain radiographs was considered proof of AVN. Absence of clinical symptoms and of radiographic findings for a minimum of 18 months after MR imaging was considered evidence of the absence of AVN. All patients were studied with plain radiography and technetium-99m methylene diphosphonate bone scintigraphy. Five hips had negative MR images, positive findings at bone marrow biopsy, positive bone pressure measurement (BMP), and positive bone scans. A comparison between MR images and bone scans showed MR imaging to be superior, with a sensitivity of 88.8% (vs. 77.5%) and a specificity of 100% (vs. 75%). BMP was the most sensitive (92%) but least specific test (57%).

Adolescent↗

PubMed1987

Avascular necrosis of the femoral head: early MRI detection and radiological correlation.

Magnetic Resonance Imaging (MRI) and conventional radiographs were compared in 49 hips with Avascular Necrosis (AVN). MRI detected AVN in 25% of the hips during the preradiological stage of the disease. Both MRI and conventional radiographs accurately detected AVN in the remaining 75% of hips. Correlation between the patterns observed with the two techniques reflected the underlying histopathologic events. The reactive interface between infarcted bone and viable bone could be identified on MRI as a low signal intensity (SI) band. On conventional radiographs the reactive interface appeared as a sclerotic band. The adjacent hyperemic zone was seen on MRI as a high SI band and as a lucent zone on the plain films. Variations of this pattern occurred as related to the extend and duration of AVN and to the individual's ability to mount a healing response. Minor degrees of collapse of the femoral head were better identified with plain radiographs but MRI demonstrated small areas of hyperintensity probably corresponding to early subchondral fractures.

Femur Head Necrosis↗

PubMed1986

Joint effusions: MR imaging.

Magnetic resonance (MR) images of the hips and knees of three healthy volunteers were reviewed and compared with images obtained from the hips of three patients with effusions. Comparison was also made with MR images obtained from two swine knees following the injections of saline in one and blood in the other. The anatomy of the knees and hips was well defined. The hip effusions were all easily recognized. MR images of the swine knees clearly demonstrated the experimentally produced joint effusions. The hip effusions and the experimentally introduced blood and saline all had long T1 and T2 values allowing easy differentiation from articular cartilage. We were unable to distinguish fresh blood from saline in the knee joints.

Adult↗