Search PubMed⌕ Search

Biomedical subjects

T H Berquist

Publications and source records attributed to T H Berquist.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Radiology of sports-related injuries.

Participation in organized sports and fitness activity continues to increase in the United States. As a result, more acute bone and soft-tissue injuries are occurring in this patient population. Chronic overuse syndromes are also more common today. It is important for radiologists to understand the mechanism of injury so that they can properly approach the imaging of these patients. Although magnetic resonance imaging (MRI) is frequently the technique of choice, other imaging methods are also important and may, in certain cases, be preferred to MRI. In this review, we discuss extremity injuries by anatomic region. The spine is not included. A tailored imaging approach to each anatomic region and type of injury is discussed.

Ankle Injuries↗
PubMedDate not supplied

Validation of three-dimensional reconstructions of knee anatomy: CT vs MR imaging.

This is the first investigation to validate the accuracy of spatial measurements based on computer-generated three-dimensional (3D) reconstructions of CT and magnetic resonance (MR) scans. Standard 3D reconstructions of one fresh frozen cadaveric knee specimen with implanted stereotactic reference markers were created. These reconstructions were based on the data from CT and MR scans performed before and after the resection of extraosseous soft tissues. The distances between the stereotactic reference markers in the 3D reconstructions were compared with the same measurements of the specimen using a Bridgeport milling machine as a precision 3D digitizer. The accuracy of intermarker distance measurements averaged 99% for CT-based reconstructions compared with 97.5% for MR-based reconstructions. Planar slices at a predetermined level and orientation through the femoral condyles were created by sequential milling of the specimen and were compared with reconstructed oblique planar CT and MR slices at the same level and orientation. The accuracy of condylar dimensional measurements was 94% for CT and 93% for MR compared with measurements of the milled slices. Three-dimensional reconstructions based on CT and MR scan data were of equally high quality and were unaffected by the status of the soft tissues.

Computer Simulation↗
PubMedDate not supplied

Field strength in neuro-MR imaging: a comparison of 0.5 T and 1.5 T.

A study was undertaken comparing neurological magnetic resonance imaging at high (1.5 T) and mid (0.5 T) field strengths. Twenty-eight patients (20 head and 8 spine) from our routine case load volunteered to undergo two consecutive and identical MR studies on the two systems. The two MR systems were built by the same manufacturer and were equipped with essentially identical hardware and software. Individual patient studies were performed consecutively in adjacent MR suites, and pulse sequence parameters were replicated exactly at the two field strengths. One exception to this rule was that the second echo of the long TR sequence in the head was acquired with a narrow receiver bandwidth on the 0.5 T system. The resulting axial double echo long repetition time (TR) and sagittal short TR head images and sagittal short and double echo long TR spine images were graded by two blinded observers (senior staff neuroradiologists) on two levels. First, the images were graded for image quality, i.e., conspicuousness of artifacts and clarity in depiction of normal and pathologic anatomy. Second, diagnostic accuracy of MR was assessed relative to the clinical-pathologic diagnosis in each case. The image quality of the 1.5 T system was rated superior in both the head and spine for most specific items assessed. This observer preference for 1.5 T images did not, however, translate into greater diagnostic accuracy for the 1.5 T system in the head. Although the 1.5 T system did have a slight advantage in diagnostic accuracy in the spine, a significant difference was not found.

Brain↗
PubMedDate not supplied

Magnetic resonance imaging in early diagnosis of Legg-Calvé-Perthes disease.

Two male patients, aged 6 and 9 years, were suspected of having unilateral Perthes disease because of typical symptoms and clinical signs. Roentgenograms, including scintigraphy, were normal. Magnetic resonance imaging (MRI) showed definite avascular necrosis in the affected hip. Roentgenograms subsequently also became positive for Perthes disease. These two cases document the advantages of MRI in early diagnosis of Perthes disease prior to development of typical radiologic changes.

Child↗
PubMedDate not supplied

Radiography of the ankle mortise.

Radiographers often use methods to position the ankle that produce inaccurate images of the ankle mortise. This article describes a technique using a 15 degree to 20 degree internal-oblique position of the leg and foot to demonstrate the ankle mortise radiographically. A textbook protocol also is included.

Ankle Joint↗