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Prompted by clinical concerns for false-negative tests, we implemented a clinical intervention consisting of a training session and an image-based verification procedure to document homogeneous radioactivity distribution in the radiolabeled meal (egg substitute per the guideline). Methods: A technologist training session emphasized the importance of thorough mixing of 99mTc-sulfur colloid in the egg meal. For 6 mo after training, an image of the prepared mixed egg was acquired before patient ingestion. Consecutive gastric-emptying studies performed 6 mo before and after training were reviewed by 2 experienced physicians. Results: There were 7 abnormal and 44 normal studies before and 15 abnormal and 29 normal studies after training (P < 0.05). Subjective evaluations of images for meal-mixing quality by 2 readers correlated with each other and with an objective measure of expected gastric-emptying physiology (correlation coefficients, 0.54 and 0.38, respectively). Conclusion: The described clinical intervention improved the accuracy of our gastric-emptying studies by decreasing false-negative studies. [ABSTRACT FROM AUTHOR]

Unlabelled: CT and PET are widely used to characterize solitary pulmonary nodules (SPNs). However, most CT accuracy studies have been performed with outdated technology and methods, and previous PET studies have been limited by small sample sizes and incomplete masking. Our objective was to compare CT and PET accuracy in veterans with SPN., Methods: Between January 1999 and June 2001, we recruited 532 participants with SPNs newly diagnosed on radiography and untreated. The SPNs were 7-30 mm. All patients underwent (18)F-FDG PET and CT. A masked panel of 3 PET and 3 CT experts rated the studies on a 5-point scale. SPN tissue diagnosis or 2-y follow-up established the final diagnosis., Results: A definitive diagnosis was established for 344 participants. The prevalence of malignancy was 53%. The average size was 16 mm. Likelihood ratios (LRs) for PET and CT results for combined ratings of either definitely benign (33% and 9% of patients, respectively) or probably benign (27% and 12%) were 0.10 and 0.11, respectively. LRs for PET and CT results for combined ratings of indeterminate (1% and 25%), probably malignant (21% and 39%), or definitely malignant (35% and 15%) were 5.18 and 1.61, respectively. Area under the receiver operating characteristic curve was 0.93 (95% confidence interval, 0.90-0.95) for PET and 0.82 (95% confidence interval, 0.77-0.86) for CT (P < 0.0001 for the difference). PET inter- and intraobserver reliability was superior to CT., Conclusion: Definitely and probably benign results on PET and CT strongly predict benign SPN. However, such results were 3 times more common with PET. Definitely malignant results on PET were much more predictive of malignancy than were these results on CT. A malignant final diagnosis was approximately 10 times more likely than a benign final diagnosis in participants with PET results rated definitely malignant.

Unlabelled: Event rates associated with a normal or low-risk myocardial perfusion SPECT imaging study have been shown by numerous investigators to be associated with <1%/y of follow-up. Thus, the aim of this study was to evaluate the prognostic value of a normal (99m)Tc-tetrofosmin study in a geographically diverse registry of patients undergoing stress myocardial perfusion SPECT. A total of 4,728 consecutively tested patients who underwent stress (99m)Tc-tetrofosmin SPECT at 5 U.S. hospitals were included in this series., Methods: Patients were monitored for the occurrence of major cardiac events and hospitalizations. Uniform methods of data collection and standardized epidemiologic methods for follow-up were used at all centers. We used a risk-adjusted, Cox proportional hazards model to assess time to cardiac death., Results: Of the 4,728 patients, one third underwent adenosine stress SPECT and two thirds underwent treadmill exercise. The observed annualized survival rate for those patients with a normal (99m)Tc-tetrofosmin study was 0.6%. Similarly, excellent survival rates were noted for the male and female subsets of this population as well as for patients who could exercise and for those undergoing pharmacologic stress testing. Compared with prior published outcomes studies on stress (201)Tl or (99m)Tc-sestamibi SPECT, the overall survival rates were similar and ranged from 99.3% to 99.7%., Conclusion: Results from this large multicenter registry provide further supportive evidence that the excellent prognosis associated with a normal SPECT scan is independent of the radiopharmaceutical used.