Accuracy, risk and the intrinsic value of diagnostic imaging: a review of the cost-utility literature.

RATIONALE AND OBJECTIVES: The aim of this study was to systematically review the reporting of the value of imaging unrelated to treatment consequences and test characteristics in all imaging-related published cost-utility analyses (CUAs) in the medical literature. MATERIALS AND METHODS: All CUAs published between 1976 and 2008 evaluating diagnostic imaging technologies contained in the CEA Registry, a publicly available comprehensive database of health related CUAs, were screened. Publication characteristics, imaging modality, and the inclusion of test characteristics including accuracy, costs, risks, and the potential value unrelated to treatment consequences (eg, reassurance or anxiety) were assessed. RESULTS: Ninety-six published CUAs evaluating 155 different imaging technologies were included in the final sample; 27 studies were published in imaging-specialized journals. Fifty-two studies (54%) evaluated the performance of a single imaging modality, while 44 studies (46%) compared two or more different imaging modalities. The most common areas of interest were cardiovascular (45%) and neuroradiology (17%). Forty-two technologies (27%) concerned ultrasound, while 34 (22%) concerned magnetic resonance. Seventy-nine (51%) technologies used ionizing radiation. Test accuracy was reported or calculated for 90% (n = 133 and n = 5, respectively) and assumed perfect (reference test or gold-standard test without alternative testing strategy to capture false-negatives and false-positives) for 8% (n = 12) of technologies. Only 22 studies (23%) assessing 40 imaging technologies (26%) considered inconclusive or indeterminate results. The risk of testing was reported for 32 imaging technologies (21%). Fifteen studies (16%) considered the value of diagnostic imaging unrelated to treatment. Four studies incorporated it as quality-of-life adjustments, while 10 studies mentioned it only in their discussions or as a limitation. CONCLUSIONS: The intrinsic value of imaging (the value of imaging unrelated to treatment) has not been appropriately defined or incorporated in the existing cost-utility literature, which could be due to a lack of evidence on the issue. Thus, more research is needed on metrics for a more comprehensive evaluation of diagnostic imaging. Similarly, the incorporation of variations in imaging tests accuracy, inconclusive results and associated risks has lacked uniformity in the cost-utility literature. Acknowledgment of these characteristics in future cost-utility publications will enhance their value and provide results that more closely resemble routine clinical practice.

Small masses on breast MR: is biopsy necessary?

RATIONALE AND OBJECTIVES: To evaluate outcome of magnetic resonance (MR)-detected biopsied breast lesions ≤5 mm by correlating imaging characteristics with pathology. METHODS AND MATERIALS: Institutional review board-approved retrospective review of 565 lesions biopsied with MR guidance between March 2004 and February 2009 found 68 lesions ≤5 mm in 61 patients. Lesions evaluated were those prospectively recommended for biopsy based on clinical setting, suspicious lesion morphology, and kinetics. Two study radiologists, blinded to final pathology, reviewed MR exams recording patient age, exam indication (staging, surveillance, diagnostic, or follow-up), mass location, size, morphology, T2-weighted signal, and kinetics. Chart review provided final pathology. RESULTS: Of 68 masses ≤5 mm, 14 (20.6%) were malignant. Of 32 <5 mm, 32 (28.1%) were malignant. Of 14 malignancies, 7 (50%) were in patients with recently diagnosed breast cancer, 6 in the same breast, of which 4 (66.7%) were in same quadrant. Higher likelihood of malignancy based on proximity to known cancer was statistically significant (P = .01). No significant difference in proportion of malignancies was found based on age, T2-weighted signal, morphology, or kinetics. CONCLUSION: For MR-detected biopsied masses, the positive predictive value for malignancy of those ≤5 mm was 20.6%. The highest prevalence of cancers was in the same quadrant as a newly diagnosed breast cancer. The decision to biopsy small masses should be based on carefully assessed MR features, and in the context of exam indication, not solely on size.