A single CT for attenuation correction of both rest and stress SPECT myocardial perfusion imaging: a retrospective feasibility study

PURPOSE

In the effort to reduce radiation exposure to patients undergoing myocardial perfusion imaging (MPI) with SPECT/CT, we evaluate the feasibility of a single CT for attenuation correction (AC) of single-day rest (R)/stress (S) perfusion.

METHODS

Processing of 20 single isotope and 20 dual isotope MPI with perfusion defects were retrospectively repeated in three steps: (1) the standard method using a concurrent R-CT for AC of R-SPECT and S-CT for S-SPECT; (2) the standard method repeated; and (3) with the R-CT used for AC of S-SPECT, and the S-CT used for AC of R-SPECT. Intra-Class Correlation Coefficients (ICC) and Choen's kappa were used to measure intra-operator variability in sum scoring.

RESULTS

The highest level of intra-operator reliability was seen with the reproduction of the sum rest score (SRS) and sum stress score (SSS) (ICC > 95%). ICCs were > 85% for SRS and SSS when alternate CTs were used for AC, but when sum difference scores were calculated, ICC values were much lower (~22% to 27%), which may imply that neither CT substitution resulted in a reproducible difference score. Similar results were seen when evaluating dichotomous outcomes (sum scores difference of ≥ 4) when comparing different processing techniques (kappas ~0.32 to 0.43).

CONCLUSIONS

When a single CT is used for AC of both rest and stress SPECT, there is disproportionately high variability in sum scoring that is independent of user error. This information can be used to direct further investigation in radiation reduction for common imaging exams in nuclear medicine.

Work-site health promotion: the effects of a goal-setting program on nutrition-related behaviors

A Goal Attainment Scaling procedure was used to quantify and evaluate change in nutrition-related behaviors of participants in a work-site wellness program. Goal Attainment Scaling is a procedure for quantifying change over time, in five categories varying from "less than expected" success to "more than expected" success. The sample consisted of 60 enlisted military personnel who had indicated, on a screening questionnaire, their desire to improve dietary practices. The subjects were assigned to three groups but remained unaware throughout the study that nutrition was being investigated. The Goal-Setting/Goal Attainment group (GSGA, no. = 19) received a full 8-week health promotion program, based on goal-setting, fitness information, and skill development (12 sessions). The Goal-Setting group (GS, no. = 19) received only the part of the program that focused on setting goals (two sessions). The control group (no. = 22) received no instruction. Results from analysis of variance indicated that GSGA had significantly higher "Change Scores" in nutrition-related behaviors than the control group (p less than .05); "Change Scores" reflect degree of dietary improvement. Frequency data indicate that dietary improvements were sustained for 84% of the GSGA members, 64% of the GS members, and 37% in the control group. These findings suggest goal-setting skills enhance individuals' capabilities for making and maintaining improvements in nutrition-related behaviors.