Influence of Prior Imaging Information on Diagnostic Accuracy for Focal Skeletal Processes-A Retrospective Analysis of the Consistency between Biopsy-Verified Imaging Diagnoses.

INTRODUCTION: Comparing imaging examinations with those previously obtained is considered mandatory in imaging guidelines. To our knowledge, no studies are available on neither the influence, nor the sequence, of prior imaging and reports on diagnostic accuracy using biopsy as the reference standard. Such data are important to minimize diagnostic errors and to improve the preparation of diagnostic imaging guidelines. The aim of our study was to provide such data. MATERIALS AND METHODS: A retrospective cohort of 216 consecutive skeletal biopsies from patients with at least 2 different imaging modalities (X-ray, CT and MRI) performed within 6 months of biopsy was identified. The diagnostic accuracy of the individual imaging modality was assessed. Finally, the possible influence of the sequence of imaging modalities was investigated. RESULTS: No significant difference in the accuracy of the imaging modalities was shown, being preceded by another imaging modality or not. However, the sequence analyses indicate sequential biases, particularly if MRI was the first imaging modality. CONCLUSION: The sequence of the imaging modalities seems to influence the diagnostic accuracy against a pathology reference standard. Further studies are needed to establish evidence-based guidelines for the strategy of using previous imaging and reports to improve diagnostic accuracy.

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer.

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard was based on a consensus decision made by a multidisciplinary team on the basis of baseline and follow-up images of the index tests, the findings of the baseline index tests by the experienced readers, and any available imaging, biochemical, and clinical data, including the response to ADT. Twenty-seven (73%) of the 37 patients had bone metastases according to the reference standard. The sensitivities for BS, SPECT/CT and NaF PET/CT were 78%, 89%, and 89%, respectively, and the specificities were 90%, 100%, and 90%, respectively. The positive predictive values of BS, SPECT/CT and NaF PET/CT were 96%, 100%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved, but not statistically superior, sensitivity compared with BS in this limited and selected patient cohort.

Diagnostic accuracy of imaging methods for the diagnosis of skeletal malignancies: A retrospective analysis against a pathology-proven reference.

OBJECTIVES: To examine the diagnostic accuracy of imaging modalities in skeletal tumours versus pathology reports. MATERIALS AND METHODS: Pathology reports of bone biopsies were compared to diagnostic imaging with X-ray, computed tomography (CT), magnetic resonance imaging (MRI), bone scintigraphy (BS), and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET/CT) performed within 6 months of biopsy. RESULTS: A total of 409 biopsies were included. Sensitivity and specificity were significantly different among the five modalities (p<0.0001). The sensitivity of MRI and PET/CT was better than CT, but CT had a better specificity than PET/CT. In general, these methods outperformed BS and X-ray. The sensitivity for osteolytic lesions varied significantly between modalities (p<0.0001), with MRI and PET/CT being more sensitive than CT. Differences in sensitivity were also observed in mixed lesions (p=0.0002) but not in osteosclerotic lesions. In spine lesions, MRI showed the best sensitivity followed by PET/CT and CT (p<0.0005 vs. MRI). There was no significant differences among non-spine lesions. CONCLUSIONS: MRI and FDG-PET/CT showed comparable diagnostic characteristics in general, in individual tumour types, and in different bone lesions and locations. Nominally, they outperformed CT in most situations. The diagnostic accuracy of X-ray and BS were notably inferior to other modalities.