Mark T. Yoshino

Bone marrow imaging using STIR at 0.5 and 1.5 T

We retrospectively examined MR images in 82 patients to evaluate the usefulness of short inversion time inversion recovery (STIR) in bone marrow imaging at 0.5 and 1.5 T. The study included 56 patients at 1.5 T and 26 patients at 0.5 T with a variety of pathologic bone marrow lesions (principally oncological), and compared the contrast and image quality of STIR imaging with spin-echo short repetition time/echo time (TR/TE), long TR/TE, and gradient-echo sequences. The pulse sequences were adjusted for optimal image quality, contrast, and fat nulling. STIR appears especially useful for the evaluation of red marrow (e.g., spine), where contrast between normal and infiltrated marrow is greater than with either gradient-echo or T1-weighted images. STIR is also extremely sensitive for evaluation of osteomyelitis, including soft tissue extent. In more peripheral (yellow) marrow, T1-weighted images are usually as sensitive as STIR. Limitations of STIR include artifacts, in particular motion artifact that at high field strength necessitates motion compensation. At 0.5 T, however, motion compensation is usually not necessary. Also, because of extreme sensitivity to water content, STIR may overstate the margins of a marrow lesion. With these limitations in mind, STIR is a very effective pulse sequence at both 0.5 and 1.5 T for evaluation of marrow abnormalities.

Diagnostic performance of teleradiology in cervical spine fracture detection

Yoshino MT, Carmody R, Fajardo LL, Seeger J, Jones K. Diagnostic performance of teleradiology in cervical spine fracture detection. Invest Radiol 1992;27:55–59.This study was done to assess the diagnostic accuracy of high-resolution (5 Ip/mm) teleradiology for detecting cervical spine fractures. Single radiographs from 25 patients with and 25 patients without cervical spine fractures were transmitted between two units of our teleradiology system (Dupont DTR 2000) located 5 miles apart. Each image was examined by four readers. Fracture detection accuracy was assessed by generating receiver operating characteristic (ROC) curves and comparing the areas under each readers curves for original and transmitted images. Two readers had statistically significant better fracture detection using nontransmitted images, whereas two had no significant differences in accuracy. The authors conclude that high resolution in and of itself is not adequate for fracture detection, and that issues concerning image contrast manipulation also will have to be addressed before teleradiology systems can be used for clinical cervical spine fracture screening.

Detection of Breast Abnormalities on Teleradiology Transmitted Mammograms

The authors conducted an observer performance study to compare breast lesion detection of conventional mammography (CM) with teleradiology (TE) transmitted mammograms. One hundred four abnormal, single-projection mammographic images were transmitted by teleradiology. Abnormalities included 11 cases with skin thickening or retraction, 48 cases with microcalcifications, and 52 with parenchymal masses. The CM and TE images were reviewed by four mammographers who indicated the type and location of abnormalities and a level of confidence for their diagnostic decisions. For each of three detection tasks--skin and nipple abnormalities, microcalcifications, and masses--receiver operating characteristic curve analysis was performed for individual readers and all readers as a group. For detecting skin and nipple abnormalities, readers performed significantly better with CM than with TE (z = 2.05, P = less than 0.04). However, no significant differences were found among readers for detection of either microcalcifications or masses. Further improvements in hardware and imaging parameters may improve detection of soft tissue abnormalities. Further evaluation is necessary to determine whether teleradiology might be applicable to breast cancer screening.

Duodenal Hematoma: CT Demonstration of the Ring Sign

This case illustrates the computed tomographic (CT) and sonographic features of duodenal hematoma. In addition, the CT scans demonstrate the ring sign, a characteristic feature noted previously only by magnetic resonance imaging.

MRI diagnosis of thoracic ossification of posterior longitudinal ligament with concomitant disc herniation

SummaryOssification of the posterior longitudinal ligament is a potentially curable cause of thoracic myelopathy. As this case illustrates, MRI can confirm the diagnosis, demonstrate other concomitant pathology such as disc herniation, and help assess the clinical significance of OPLL by showing spinal word compression.

Evaluation of the DuPont Teleradiology System

This paper describes a digital teleradiology system developed by the DuPont Corporation and some of the psychophysical and clinical evaluations we have conducted on the system in the last two years.

Comparison Of Conventional Film/Screen To Photo-Stimulable Imaging Plate Radiographs For Intraoperative Arteriography And Cholangiography

This prospective study compared images obtained using a photo-stimulable imaging plate (IP) to images obtained using a conventional film/screen (FS) combination in a total of 66 patients, 26 of whom were undergoing surgical procedures requiring intra-operative arteriography and 40 of whom were undergoing cholangiography. Exposure factors, number of repeat examinations, and elapsed time for processing each image were recorded. Diagnostic accuracy of the two techniques was assessed objectively and image quality was assessed subjectively. The radiation dose was reduced by 50% using the IP technique. Due to the greater dynamic range of the IP system, no repeat IP examinations were required for either arteriography or cholangiography, while 6 (9%) of the FS studies had to be repeated due to under- or over-exposure. IP studies required very slightly more time for processing than FS studies, an average of 35 seconds per patient. Receiver operating characteristic (ROC) analysis revealed no significant difference in diagnostic accuracy between the two imaging techniques for either the arteriographic or cholangiographic studies. Subjective evaluation also revealed no significant difference in observer preference for IP vs FS studies.