Paul N. Olson

The prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in two large American Midwest metropolitan hospital populations

Abstract Objective. There are no published large-scale studies of the overall prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and it has been proposed that the prevalence is greater than previously reported. We thus decided to review chest radiographs in a population of patients over 50 years of age seen at two large but differing metropolitan hospitals in a major American Midwest city. Design and patients. The posterior-anterior and lateral chest radiographs of 1363 patients were reviewed for evidence of DISH at the University of Minnesota Hospital and Clinic. There were 500 consecutive inpatient admissions, 540 consecutive patients who attended the outpatient clinics and 326 patients collected from our film archive. A population of 1001 patients seen at Hennepin County Medical Center was also studied. It was possible to subclassify this latter group with respect to race. Results and conclusion. Using strict criteria, i.e., four or more levels involved, the overall prevalence of DISH in the male population over age 50 years was 25% and in the female population over age 50 years was 15%. This prevalence climbed to 28% in males over 80 years and to over 35% in males over age 70 years. In females over 80 years, the prevalence was found to be 26%. Although our population base was small, DISH was found to be less common in the black, Native-American and Asian populations. The prevalence of DISH was also found to be far lower in a similar white population with osteoporosis. The overall prevalence of DISH was higher than expected in a predominantly white population over age 50 years with a lesser incidence in the black, Native-American and Asian populations, suggesting a genetic origin of the condition.

Hyperextension strain or “whiplash” injuries to the cervical spine

PurposeTo define “whiplash” radiologically. Material and methods. A full cervical spine radiographic series (including flexion and extension views) was reviewed in 40 patients with clinically proven “whiplash” injuries and compared to the radiographs in 105 normal controls. The level and degree of kinking or kyphosis, subluxation, and the difference in the amount of fanning between spinous processes on flexion and extension films were measured in each patient.ResultsLocalized kinking greater than 10° and over 12 mm of fanning, often occurring at the level below the kinking or kyphosis, occurred mainly in the group of whiplash patients (sensitivity 81%, specificity 76%, accuracy 80%).ConclusionsLocalized kinking greater than 10° and fanning greater than 12 mm are useful measurements by which to separate patients with true whiplash injuries from those with minor ligamentous tears. Flexion and extension views are essential to help define whiplash and other ligamentous injuries of the cervical spine.

Use of MRI in Evaluating Postoperative Changes in Patients With Bone and Soft Tissue Tumors

We reviewed the clinical, surgical and magnetic resonance imaging (MRI) findings in 80 patients who underwent resection of primary benign or malignant bone or soft tissue tumors. There were 18 benign and 62 malignant tumors. Although 31 patients were originally thought to have recurrence, on review only 20 patients were considered to have recurred. Of these, three were found only to have postoperative changes at surgery. Seventeen patients actually had recurrence of tumor. We believe that the presence of an actual mass lesion on MRI is the cornerstone for the correct diagnosis of recurrent tumor.

Case report 703

Abstract There are two theories concerning the origin of multifocal osteogenic sarcoma: In one, the lesions all arise synchronously as multiple, simultaneously appearing, primary tumors, and in the other, there appears to be one dominant site with early and rapidly progressive metastatic disease. We believe that our patient fits into the second group with a primary right (distal-end) femoral osteogenic sarcoma with early and rapid metastasis. Bone scan, chest CT, and MRI examinations played an essential role in the initial evaluation and follow-up of this patient with osteosarcomatosis. The multiple modalities also offered a greater sensitivity in the detection and for the surveillance of the progression of the condition.

Case report 853

Fig. 2. A Posteroanterior and B lateral radiographs of the chest (March 1992). A small right hilar nodule is indicated by the arrow. The thoracic spine appears normal Fig. 3. A Posterior and B lateral radiographs of the chest (April 1992). A small right hilar nodule is again noted. New collapse of the T6 vertebral body is demonstrated Fig. 4. Tl-weighted sagittal MRI of thoracic spine, showing replacement of normal signal marrow signal and collapse of the T6 vertebral body. A mass is seen to extend out of the vertebral body Clinical information