RSNA 2012 

Abstract Archives of the RSNA, 2012


SSK16-04

CT Technologist and Radiologist Thresholds for Repeat Series Examinations for CTs of the Head

Scientific Formal (Paper) Presentations

Presented on November 28, 2012
Presented as part of SSK16: Physics (CT Dose Optimization)

Participants

Jaron Chong MD, Presenter: Nothing to Disclose
Natalia Gorelik, Abstract Co-Author: Nothing to Disclose
Prasad Baladev Hanagandi MBBS, Abstract Co-Author: Nothing to Disclose
Raquel Del Carpio-O'donovan MD, Abstract Co-Author: Nothing to Disclose
Carlos I. Torres MD, Abstract Co-Author: Nothing to Disclose
Jeffrey Chankowsky MD, Abstract Co-Author: Nothing to Disclose

PURPOSE

A CT radiation dose audit of our tertiary care institution demonstrated that many of our dose outliers were due to repeated partial volumes of CT heads secondary to image artifact. We noted that many of these repeat series were minimally diagnostic, were centered at the posterior fossa, and often involved radiosensitive tissues (i.e. lens). As part of a multi-pronged intervention, we designed an experiment to assess the differences in repeat thresholds between technologists, staff, and fellow-level radiologists.

METHOD AND MATERIALS

30 non-contrasted CT Head studies with the greatest overlapping CTDIvol and number of repeat series were selected yielding 122 image acquisitions. The scan-range of maximal overlap was isolated and the image slice with the greatest artifact was exported and repeated for all series and studies.  A randomized blinded exam was administered to 8 CT technologists, 2 board-certified staff, and 1 neuroradiology sub-specialist fellow. Examinees were shown all image slices, asked to rate image quality, and commit to whether they would repeat the acquisition if in a clinical setting, under a traumatic clinical context. Post-exam qualitative comments were solicited to gain insight into the rationales of staff, fellows, and technologists.

RESULTS

Of the 11 participants, a total of 1,342 assessments were made of the set of 122 randomized images. The CT technologists rated mean image quality lower than the radiologists (3.2 vs. 3.7) and opted to repeat acquisitions an average of 50.8% (Range: 36–62%) of the time versus 22.6% (7.4–44.3%) for the radiologists. Overall kappa inter-rater agreement was moderate in both groups, but slightly higher between the radiologists (0.52 vs. 0.45). There was increased consensus at the higher-end of the image quality scale.

CONCLUSION

Our findings suggests overall homogeneously low thresholds to repeat series in our CT technologists and a heterogeneous, but overall higher threshold to repeat amongst our staff and fellows. Specific interventions to bring the repeat rate and protocols of the technologists more in line with the staff radiologists could yield benefits with respect to radiation dose exposure as well as workflow efficiency.

CLINICAL RELEVANCE/APPLICATION

While image quality is paramount, overemphasis can encourage unduly conservative thresholds to repeat acquisitions. Clear and specific indications to repeat should be established with technologists.

Cite This Abstract

Chong, J, Gorelik, N, Hanagandi, P, Del Carpio-O'donovan, R, Torres, C, Chankowsky, J, CT Technologist and Radiologist Thresholds for Repeat Series Examinations for CTs of the Head.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12031416.html