Felix S. Chew

Computer-Assisted Instruction with Interactive Videodisc Versus Textbook for Teaching Radiology

RATIONALE AND OBJECTIVESnWe compared computer-assisted instruction with interactive videodisc (CAI-videodisc) with a textbook to study differences in educational efficacy, time spent, and subjective preferences.nnnMETHODSnTwo modules of CAI-videodisc, one concerning the radiology of arthritis and the other skeletal trauma, were prepared specifically for advanced medical students and junior house staff. Because the modules were derived from an actual textbook, we were able to conduct a controlled comparison. Our participants were 103 third- and fourth-year medical students taking a required 2-week clerkship in diagnostic radiology. They were assigned as part of their coursework the CAI-video-disc version of one module and the textbook version of the other. Pre- and posttests were administered.nnnRESULTSnThe mean scores improved from pre- to posttest after students used both modules in either version (P < 0.001). The gain in score was greater for students using CAI-videodisc; this difference was small only for the arthritis module (P < 0.092), but it was large for the trauma module, even when adjusted for differences in time spent learning (P < 0.001). Significantly more time was spent on the CAI-videodisc versions than the textbook versions (P < 0.004). Subjectively, 43% of the students preferred the CAI-videodisc, 45% preferred the textbook, and 11% had no preference.nnnCONCLUSIONnMedical students learned more radiology using a CAI-videodisc program than reading a textbook, but spent more time doing so. Their subjective preferences were equally split.

CT-guided aspiration in potentially infected total hip replacements complicated by heterotopic bone

Aspiration of the hip joint in the setting of a potentially infected total hip replacement is occasionally unsuccessful under fluoroscopic guidance because of periarticular heterotopic bone. Of 136 consecutive patients with total hip replacements who were referred to the radiology department for hip aspiration because of suspected infection, successful intraarticular needle placement was achieved in 132 (97%) under fluoroscopic guidance. In four (3%) cases, the attempted aspiration was unsuccessful because heterotopic bone prevented the needle tip from reaching the joint; a second attempt was performed successfully under CT guidance. CT confirmed that the anterior approach was completely blocked by heterotopic bone and that there was a gap in this bone elsewhere through which a needle could be passed into the joint. The increased cost of CT was modest because it was necessary in only a small percentage of patients.

Learning radiology from interactive videodiscs: Bar-code book versus computer-assisted instruction

RATIONALE AND OBJECTIVESnWe compared an interactive videodisc with bar-code book with an interactive videodisc with computer-assisted instruction for learning radiology to determine whether there would be differences in instructional effectiveness, instruction time, or subjective preference.nnnMETHODSnTwo different videodisc modules were created. Each was presented in two formats with identical content: bar-code book and computer-assisted instruction. In a controlled crossover experimental design, 48 fourth-year medical students were assigned one bar-code book module and one computer module. Pre- and posttests were administered.nnnRESULTSnMean scores improved from pretest to posttest after students used the modules in either format (p < .01). There were no significant differences between students who used the bar-code book and those who used the computer in pretest scores, posttest scores, gains in score from pretest to posttest, or instruction time for either module. Subjectively, 74% of the students preferred computer-assisted instruction, 20% preferred bar-code book, and 7% preferred neither.nnnCONCLUSIONnAlthough bar-code book and computer versions of an interactive videodisc can be educationally equivalent, most students preferred the computer. When videodisc is being integrated into the curriculum, the choice between bar-code book and computer-assisted instruction can be made on the basis of noneducational factors such as cost and availability.

Radiographic pseudochondrocalcinosis in early failure of a cemented total knee replacement.

We observed a case of early-onset osteolysis in a cemented total knee arthroplasty. Preoperative radiographs suggested numerous radiopaque particles covering the polyethylene insert. Findings at the time of revision confirmed the presence of small radiopaque polymethylmethacrylate particles on the bearing surface of the tibial insert, presumably leading to early failure of the knee arthroplasty.

Advanced microcomputer-aided medical illustration

In a visually oriented field such as diagnostic radiology, illustrations, diagrams, and other types of art-work can complement verbal description and photographs, simplify the description of anatomic concepts, and add interest and aesthetic value to a presentation or manuscript. The vast potential of the microcomputer for creating high-quality art and graphics is being realized by the availability of high-level illustration programs running on fast computer systems. Advanced microcomputer applications for illustration have the tools to compose and execute drawings of virtually unlimited detail and complexity. Digitized images can be used as drawing templates or as components of finished art. Text is easily incorporated. Each individual element of a drawing can be changed or edited without altering other portions of the drawing. Finished art can be output to laserxerographic printers, film recorders, and photo imagesetters.