Intraobserver, interobserver, and day-to-day reproducibility of quantitative 99mTc-HYNIC annexin-V imaging in head and neck carcinoma.

RATIONALE: For clinical application, a sufficient reproducibility of 99mTc-HYNIC annexin-V quantitative uptake measurements must be demonstrated to allow a study of cell-death changes induced by chemotherapy over time and intersubject. Thus, the aim of this study was to estimate the intra-, inter-, and day-to-day reproducibility of quantitative 99mTc-HYNIC annexin-V tumor uptake values in patients suffering from head and neck carcinomas.

METHODS

Thirteen (13) patients suffering from clinically suspected, histologically confirmed squamous head and neck carcinomas were prospectively included in the study. All patients were scheduled to undergo a spiral computed tomography scan and two 99mTc-HYNIC annexin-V scintigraphies within 3-5 days from each other, referred to as day 1 and day 2 of scintigraphy. The percentage of uptake of the injected dose of 99mTc-HYNIC annexin-V in tumor lesions on scintigrams divided by the tumor volume, as derived from CT, was determined twice within an interval of 2 weeks by observer 1 and once by observer 2 on day 1 of scintigraphy and once on day 2 of scintigraphy by observer 1.

RESULTS

The mean of the difference for the intra-, inter-, and day-to-day measurements were -3.4%, 2.4%, and -6%, respectively. No systematic bias was observed for the mean of the differences for the intra-, inter-, and day-to-day measurements. The respective confidence intervals for the mean of the differences of intra-, inter-, and day-to-day variability were -8.2%-1.4%, -2.9%-7.8%, and -14.7%-2.7%.

CONCLUSION

The reproducibility of quantitative 99mTc-HYNIC annexin-V tumor uptake measurements using a manual method appears to be acceptable for clinical use.