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J L Bloem

Publications and source records attributed to J L Bloem.

At least 19 recordsLinked to original sources
PubMed1992

MR imaging of skeletal metastases from medulloblastoma.

The findings of MR imaging in 3 patients with bone metastases from medulloblastoma are reported. The first patient showed focal lesions of low signal intensity on T1-weighted spin echo images at a time when bone scintigraphy was negative for metastases. This patient later developed extensive osteosclerotic lesions visible on plain films. The bone marrow of the second patient showed diffuse low signal intensity on T1-weighted images. After chemotherapy the signal intensity of the bone marrow increased which correlated with a return of normal hematopoietic tissue. A response to chemotherapy was also found on MR imaging and repeat bone marrow biopsies in a third patient. A consistent finding was a low signal intensity on pre-gadolinium images, but the pattern (focal or diffuse abnormal signal intensity) was different in each patient. To our knowledge, this is the first report on MR imaging findings in bone metastases from medulloblastoma.

Acetabulum↗
PubMed1992

Magnetic resonance imaging of Achilles tendon xanthomas in familial hypercholesterolemia.

The demonstration of tendon xanthomas is helpful in diagnosing heterozygous familial hypercholesterolemia, but in many patients lipid may accumulate without clinical abnormality being present. We investigated the possibility of detecting the lipid element with magnetic resonance (MR) imaging in seven patients with familial hypercholesterolemia and six controls. Although the mean relative signal intensities measured on long TR/TE spin echo sequences of the tendon were significantly higher in patients than in controls, the lack of such elevation does not rule out the presence of such lesions. In vitro measurements indicated that the signal intensity of triglycerides was quenched by cholesterolesters. The anatomic findings of MR imaging were compared with those of ultrasonography (US), showing excellent correlation in measurements between MR images and US [r(S) = 0.95 and 0.97 respectively]. MR imaging and US provide equal information on the anatomy of the Achilles tendon; as an abnormally increased signal intensity within the xanthoma on MRI was found in only a minority of our patients, the value of MRI in the demonstration of Achilles tendon xanthomas is limited when using conventional T1 and T2 spin echo sequences.

Achilles Tendon↗
PubMed1992

The signal intensity of the normal odontoid process (dens) displayed on magnetic resonance images.

In order to analyse the normal signal intensity of the medullary space of the odontoid process (dens) relative to age, the craniovertebral junction of 33 asymptomatic volunteers in six age groups was examined by means of magnetic resonance imaging. To avoid partial-volume effects 3-mm slices were used in sagittal and axial planes. The signal intensities relative to cerebral white matter varied from 0.51 to 1.23 in the sagittal plane and 0.56 to 1.51 in the axial plane. The signal intensities relative to muscle varied from 0.76 to 2.40 in the sagittal plane and 0.96 to 2.30 in the axial plane. The signal intensities relative to fat varied from 0.22 to 0.62 in the sagittal plane and 0.23 to 0.68 in the axial plane. No correlation with age of the volunteers was found. The normal medulla of the dens may exhibit a low signal intensity on T1-weighted images irrespective of age.

Adipose Tissue↗
PubMed1992

A surgical approach in total shoulder arthroplasty.

The long deltopectoral approach promoted by Neer is the standard for performing a total shoulder arthroplasty. However, this exposure is inadequate for preparation and bone grafting of the glenoid cavity or repairing an associated large rotator cuff tear. In the anatomy laboratory we looked for an alternative approach to the glenohumeral joint which would accommodate these difficulties. Afterwards we used this approach in 7 of 13 patients in whom a Biomet Bio-modular shoulder arthroplasty was planned. The study is prospective with a 1-year follow-up of 12 cases.

Aged↗
PubMed1992

Osteosarcoma: chemotherapy-induced changes at MR imaging.

Fifty-seven patients undergoing chemotherapy for osteosarcoma underwent evaluation with magnetic resonance (MR) imaging to identify changes related to a good or poor response. Spin-echo MR images obtained after preoperative chemotherapy were compared with images obtained before treatment. Histopathologic examination of each resected specimen was used to quantify the response. An increase in tumor volume and increased or unchanged edema were predictive of a poor histopathologic response (predictive values, 85%-92%). Decreased or unchanged tumor volume and a decrease in edema were poor predictors of a good response (predictive values, 56%-62%). Improved tumor demarcation, an increase in the size of areas of low signal intensity, and a decrease in joint effusion occurred independently of histopathologic response in almost half of the patients. With a subjective interpretation of MR images, poor respondents can be identified if an increase in tumor volume or no decrease in the amount of edema is seen. Subjective criteria do not contribute to the identification of good respondents.

Adolescent↗
PubMed1992

Imaging of soft tissue tumors.

In a patient presenting with a soft tissue tumor, radiographs are needed to visualize or exclude osseous involvement. Ultrasound can be used to visualize the lesion for cytologic biopsy. If cytology does not rule out sarcoma, magnetic resonance imaging is indicated to stage the lesion. As a rule staging studies other than MR imaging are not needed to evaluate the local situation. Usually MR imaging does not assist in suggesting a specific diagnosis. In certain instances, however, morphology or the presence of high signal intensity on T1, or low signal intensity on T2-weighted images increases specificity. Thick needle biopsy or open biopsy should be performed following MR imaging. This reduces sample errors and increases the accuracy of preoperative staging.

Diagnostic Imaging↗
PubMed1991

Detection of vertebral metastases: comparison between MR imaging and bone scintigraphy.

In a double-blind, prospective study, the authors analyzed bone scintigrams and magnetic resonance (MR) images of the spine in 71 patients with histologically proved skeletal metastases. Bone scintigrams and MR images were separately reviewed by four independent observers. Bone scintigraphy permitted identification of 499 abnormal vertebrae and MR imaging, 818 abnormal vertebrae. MR imaging depicted additional abnormal vertebrae in 49 patients. The authors conclude that MR imaging is more sensitive than bone scintigraphy in detection of vertebral metastases.

Adolescent↗
PubMed1991

Cystic fibrosis: MR imaging of the pancreas.

The appearance of the pancreas in 17 adult patients with cystic fibrosis was evaluated with magnetic resonance (MR) imaging. The pancreas was abnormal in 15 patients. Three patterns were observed: (a) lobulated enlarged pancreas with complete replacement by fatty tissue (n = 9), (b) small atrophic pancreas with partial replacement by fat tissue (n = 5), and (c) diffuse atrophy of the pancreas without fatty replacement (n = 1). Replacement of the pancreas by fat tissue was seen on T1-weighted images with, characteristically, a very high signal intensity. The sensitivity of MR imaging in depicting pancreatic abnormality in cystic fibrosis is 94%, which is comparable to that of computed tomography.

Adolescent↗
PubMed1991

Sequential magnetic resonance imaging in Perthes' disease.

Forty-eight images using magnetic resonance imaging (MRI) in 16 hips with Perthes' disease were evaluated over a mean period of two years. MRI depicted exactly the infarcted zone in the femoral head before typical radiological changes were evident. Early determination of the extent of the infarcted bone on MRI benefits those patients who require treatment. Follow-up MRI scans at six-monthly intervals, reflected the chronological stages of the repair process in each group classified according to Catterall.

Child↗
PubMed1991

Fibrous dysplasia vs adamantinoma of the tibia: differentiation based on discriminant analysis of clinical and plain film findings.

Differentiation between benign fibrous dysplasia and malignant adamantinoma of the tibia is challenging because of the impact the diagnosis has on the choice of treatment (none or extensive surgery). The histologic and pathologic similarities of the lesions and the controversial relationship between fibrous dysplasia, osteofibrous dysplasia, and adamantinoma complicate the matter. We found a large overlap of histologic features in lesions considered either fibrous dysplasia or osteofibrous dysplasia on the basis of the radiologic findings. The purpose of this study was to determine the value of the plain radiograph of the lower leg in combination with clinical findings to differentiate the benign from the malignant condition. The clinical symptoms, radiographs, and histologic slides of 46 patients with fibrous dysplasia and 22 with adamantinoma in the tibia were reviewed retrospectively. In only one of 12 patients with radiologic or histologic characteristics of osteofibrous dysplasia were both radiologic and histologic criteria for the diagnosis present. A linear discriminant analysis was performed on six clinical (age, spontaneous pain, pain after trauma, swelling only, pain and swelling, and bowing deformity) and 25 radiologic signs. Fibrous dysplasia and its variant osteofibrous dysplasia could be identified correctly in 87% (40 of 46 patients) and adamantinoma in 95% (21 of 22 patients) by using the patient's age and four radiologic signs. When results from the discriminant analysis of a randomized subgroup of patients (32) were used on the other subgroup (36 patients), fibrous dysplasia was correctly identified in 84% (21 of 25) and adamantinoma in 82% (nine of 11). Fibrous dysplasia is more prevalent than adamantinoma in a young patient, when radiographs show a ground-glass appearance and anterior bowing and when there is no multilayered periosteal reaction and moth-eaten destruction. When radiologic signs and the patient's age are combined, fibrous dysplasia and adamantinoma can be discriminated in a high percentage of patients.

Adolescent↗
PubMed1991

Hepatic metastases: comparative study of diagnostic ultrasound, CT, nuclear scintigraphy and laboratory tests.

Computed tomography, ultrasound, nuclear scintigraphy, and laboratory tests (lactic dehydrogenase, alkaline phosphatase, and 5-nucleotidase) were compared in 135 patients with gastro-intestinal carcinoma to define the most useful test to detect hepatic metastases. Thirty-six patients (26.7 per cent) had hepatic metastases at laparotomy. Sensitivities were low: 46.2 per cent for nuclear scintigraphy, 57.6 per cent for ultrasound, 67.7 per cent for computed tomography and 62.9 per cent for lactic dehydrogenase. Accuracies ranged from 62.9 (lactic dehydrogenase) to 77.6 per cent (nuclear scintigraphy). No significant differences were found. Accurate and efficient detection of hepatic metastases is hampered by relatively low sensitivity, specificity and accuracy of the conventional imaging tests and laboratory tests.

Diagnostic Tests, Routine↗
PubMed1991

Magnetic resonance imaging in acetabular residual dysplasia.

Eighteen hips in 15 children showed persistent roentgenographic evidence of congenital acetabular residual dysplasia at four- to eight-year follow-up evaluations. The mean follow-up period was 5.8 years. These hips were subsequently evaluated by magnetic resonance (MR) imaging. MR imaging studies revealed thick unossified chondroepiphyseal cartilage of the acetabular roof adjoining the ilium in all hips. The cartilage in these hips counterbalanced the steep acetabular slope seen on roentgenograms. Initially these hips were regarded as candidates for an acetabular reconstruction, but 11 hips displayed sufficient cartilaginous acetabular coverage on MR images. MR imaging promotes more accurate selection of patients for acetabular reconstruction and aids in the choice of the most appropriate type of acetabular reconstruction.

Acetabulum↗
PubMed1990

A correlative study of MR images and cryo-sections of the neonatal hip.

The complex anatomy of the neonatal hip is often difficult to image. Recently, magnetic resonance imaging (MRI) has been used to evaluate the normal and abnormal neonatal hip. We correlated the MRI scans of the hip of a newborn cadaver with multiplanar cryo-sections stained according to Mallory-Cason, to detail the anatomic structures of the normal hip joint space. In our experience, MRI was shown to provide excellent depiction of hip anatomy.

Hip Joint↗
PubMed1990

Magnetic resonance imaging of the shoulder in patients with rheumatoid arthritis.

To evaluate the ability of magnetic resonance imaging (MRI) to detect shoulder abnormalities 18 patients (36 shoulders) with rheumatoid arthritis (RA) and shoulder complaints were studied. Osseous abnormalities of the glenoid and humeral head were readily detected with MRI. The imaging planes used were not suitable for the evaluation of acromioclavicular joint involvement. Magnetic resonance imaging depicted soft tissue abnormalities that were not clearly visualised by plain film radiography, such as involvement of rotator cuff tendons and subacromial bursae, joint effusion, and muscular atrophy. Magnetic resonance imaging appears to be a sensitive method for evaluation of glenohumeral joint changes in patients with RA.

Adult↗
PubMed1990

Primary Ewing sarcoma of rib.

Ewing sarcoma is a relatively common, highly malignant bone tumor that typically occurs in adolescents and young adults aged 10-25 years. Our archives contain 328 cases of histologically proved and radiologically correlated Ewing sarcoma collected in consultation over 40 years. From this series, we identified 34 lesions (10%) arising in ribs. Radiographically, the affected rib was predominantly lytic in most (82%) cases, but mixed lytic-sclerotic (9%) and even predominantly sclerotic (9%) patterns were also encountered. The affected rib was "expanded" in 35% of cases, although the contour change was usually mild. Abnormalities of the affected ipsilateral hemithorax varied from subtle, isolated rib involvement to solitary rib involvement accompanied by complete opacification of the hemithorax. We describe the spectrum of radiologic findings of primary Ewing sarcoma of rib, augmented where appropriate by accompanying pathologic material.

Adolescent↗
PubMed1990

The value of MR imaging in monitoring the effect of chemotherapy on bone sarcomas.

We studied the value of MR imaging in monitoring the response of Ewing sarcoma and osteosarcoma to chemotherapy. Relative signal-intensity changes on MR images in the course of chemotherapy were compared with changes in tumor volume and histopathologic findings. MR scans (T1- and T2-weighted spin-echo images) were obtained in 20 patients with bone sarcoma. The first MR scan was obtained before the administration of chemotherapy in all patients. The follow-up scan was obtained in the course of treatment, before surgery. Tumor-volume and signal-intensity measurements of the intra- and extraosseous components of the tumor were analyzed. In 17 patients, histopathologic findings of the resected tumor were available for comparison with the MR images. In 12 of 17 patients there was complete agreement between changes in tumor volume, changes in the signal intensity of the extraosseous tumor component on T2-weighted images, and histopathology. In another four cases, changes in signal intensity correlated either with histopathology or with changes in tumor volume. In one patient with a pathologic fracture, no such correlation existed. A significant correlation was found between changes in signal intensities and pathologic response (r = .57, p = .02), as well as between changes in tumor volume and pathologic response (r = .53, p = .03). No correlation could be found between changes in signal intensity of the intraosseous tumor component and changes in tumor volume or histopathology. We conclude that the signal intensity of the extraosseous component of bone sarcomas on T2-weighted MR images in addition to changes in tumor volume may be useful in evaluating response to chemotherapy.

Adolescent↗