Retrospective case-control study to predict a potential underlying appendiceal tumor in an acute appendicitis context based on a CT-scoring system.

OBJECTIVES: To assess CT signs to discriminate an appendiceal tumor versus a non-tumoral appendix in an acute appendicitis context. METHODS: A 10-year bicentric retrospective case-control study was performed in adults. Patients with a histopathological appendiceal tumor and appendicitis were paired for age and sex with patients with non-tumorous appendicitis (1/3 ratio, respectively). Two senior radiologists blindly analyzed numerous CT findings with final consensus to perform univariate and multivariate statistical analyses. A diagnostic CT scan score was calculated with a bootstrap internal validation. Reproducibility was assessed based on the kappa statistic. RESULTS: A total of 208 patients (51 +/- 21 years; 114 males) were included (52 patients in the tumor group and 156 in the non-tumor group). In the multivariate analysis, an appendicolith and fat stranding were protective factors with OR = 0.2 (p = 0.01) and OR = 0.3 (p = 0.02), respectively, while mural calcifications (OR = 47, p = 0.0001), an appendix mass (OR = 7.1, p = 0.008), a focal asymmetric wall abnormality (OR = 4.9, p = 0, 001), or a ≥ 15 mm diameter (OR = 3.5, p = 0.009) were positive predictive factors of an underlying tumor. Using a ≥1 cut-off, our diagnostic score had an AUC = 0.87 (95 % CI, 0.82-0.93) and a positive likelihood ratio = 13.5 (95 % CI, 6.7-27.1). CONCLUSION: We developed a reliable scoring system based on CT findings, which is highly predictive of an underlying appendiceal neoplasm in an appendicitis context using a ≥1 cut-off.

Breast tomosynthesis: What do we know and where do we stand?

Digital breast tomosynthesis (DBT) is a new imaging technology that addresses the limitation caused by overlapping structures in conventional two-dimensional digital mammography owing to the acquisition of a series of low-dose projection images. This unique technique provides a dual benefit to patients screened for breast cancer. First, DBT increases the cancer detection rate mostly by highlighting architectural distortions and allowing better assessment of masses shape and margins. Second, DBT helps reduce recall rate by discarding asymmetries related to overlapping tissue. However, DBT is not included in the majority of cancer screening programs worldwide. Several issues still need to be addressed such as over-diagnosis and over-treatment, lack of reduction of interval breast cancer, quality control and storage, and radiation dose. In the diagnostic setting, DBT increases the diagnostic accuracy and reduces the number of indeterminate lesions in symptomatic women. Its aforementioned performances regarding asymmetries, masses and architectural distortions allow reducing the number of additional views while working-up a screening-detected lesion. Tumor size is also better assessed at DBT as well as multicentricity, two significant benefits in the staging of breast cancer. Finally, DBT allows a better analysis of scars and helps reduce the rate of indeterminate findings after surgery. Although somewhat limited by high breast density, DBT globally outperforms digital mammography in both screening and diagnostic breast imaging. Additional research is however needed, particularly on relevant screening outcomes. This review describes the main performances of breast DBT in breast cancer screening and diagnosis and the resulting consequences in both settings.

Ultra-low-dose chest CT with iterative reconstruction does not alter anatomical image quality.

PURPOSE: To evaluate the effect of dose reduction with iterative reconstruction (IR) on image quality of chest CT scan. MATERIALS AND METHODS: Eighteen human cadavers had chest CT with one reference CT protocol (RP-CT; 120kVp/200mAs) and two protocols with dose reduction: low-dose-CT (LD-CT; 120kVp/40mAs) and ultra-low-dose CT (ULD-CT; 120kVp/10mAs). Data were reconstructed with filter-back-projection (FBP) for RP-CT and with FBP and IR (sinogram affirmed iterative reconstruction [SAFIRE®]) algorithm for LD-CT and ULD-CT. Volume CT dose index (CTDIvol) were recorded. The signal-to-noise (SNR), contrast-to-noise (CNR) ratios of LD-CT and ULD-CT and quantitative parameters were compared to RP-CT. Two radiologists reviewed the CT examinations assessed independently the quality of anatomical structures and expressed a confidence level using a 2-point scale (50% and 95%). RESULTS: CTDIvol was 2.69 mGy for LD-CT (-80%; P<0.01) and 0.67 mGy for ULD-CT (-95%; P<0.01) as compared to 13.42 mGy for RP-CT. SNR and CNR were significantly decreased (P<0.01) for LD-CT and ULD-CT, but IR improved these values satisfactorily. No significant differences were observed for quantitative measurements. Radiologists rated excellent/good the RP-CT and LD-CT images, whereas good/fair the ULD-CT images. Confidence level for subjective anatomical analysis was 95% for all protocols. CONCLUSIONS: Dose reduction with a dose lower than 1 mGy, used in conjunction with IR allows performing chest CT examinations that provide a high quality of anatomical structures.