Distribution of liver stiffness in non-alcoholic fatty liver disease with higher fibrosis-4 index than low cut-off index.

BACKGROUND AND AIM: In the condition of high prevalence of non-alcoholic fatty liver disease (NAFLD), a new diagnostic algorithm to efficiently identify NAFLD patients with significant fibrosis is urgently required. We evaluated the predictive ability of the fibrosis-4 index (FIB-4 index) for significant liver fibrosis (F ≥ 2) in a cohort of Japanese patients with NAFLD. METHODS: We prospectively calculated the FIB-4 index in patients who were incidentally diagnosed as fatty liver in medical checkups and then conducted liver stiffness measurement by vibration-controlled transient elastography (VCTE) only in patients in whom the FIB-4 index was more than the low cut-off index (> 1.45). RESULTS: Of the 5929 people who underwent medical checkups, a total of 1374 people were identified as having fatty liver. Among these, we performed VCTE in 106 patients in whom the FIB-4 index was higher than 1.45. The distribution of the fibrosis stage as estimated by VCTE in the patients was as follows: F0, 52.8%; F1, 10.3%; F2, 21.6%; F3, 11.3%; and F4, 3.7%. The positive predictive value of the FIB-4 index for detecting NAFLD with significant fibrosis was 36.6%. The minimum value of the FIB-4 index was constant for each estimated fibrosis stage. CONCLUSIONS: This is the first prospective study to evaluate the usefulness of the FIB-4 index as the first step to screen NAFLD patients with significant fibrosis. In Japan, addition of one further step that combined with the FIB-4 index is necessary to meaningfully reduce the number of patients needing liver stiffness measurement or liver biopsy.

A preliminary report of breast cancer screening by positron emission mammography.

OBJECTIVE: Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) and PET/computed tomography (PET/CT) have had a considerable impact on the detection of various malignancies. PET and PET/CT are minimally invasive methods that can provide whole-body imaging at one time. Therefore, an FDG-PET cancer screening program has been widely used in Japan. However, the breast cancer detection rate of FDG-PET cancer screening is relatively low. Therefore, FDG-PET screening is not recommended for breast cancer screening. Positron emission mammography (PEM) is a high-resolution molecular breast imaging technology. PEM can detect small breast cancers that cannot be detected on PET or PET/CT images due to limited spatial resolution. We have performed opportunistic breast cancer screening using PEM since 2011. To the best of our knowledge, this is the first report regarding PEM breast cancer screening. METHODS: This study enrolled 265 women. PEM images were analyzed by agreement of 2 experienced nuclear medicine physicians. The readers were given information from medical interview sheet. US findings were interpreted holistically. The number of participants, patient recall rate, further examination rate, and cancer detection rate by year were calculated. RESULTS: The overall recall rate was 8.3%; the work-up examination rate was 77.3%, and cancer detection rate was 2.3%. The positive predictive value of PEM was 27.3%. Six cancers were found by PEM screening. Five were invasive cancers and one was ductal carcinoma in situ. Histological tumor sizes were reported in three cases: 0.7, 1.2, and 2 cm. CONCLUSION: PEM screening appears to have potential for breast cancer screening.

Positron emission mammography (PEM): reviewing standardized semiquantitative method.

PURPOSE: To validate semiquantitative analysis of positron emission mammography (PEM). METHODS: Fifty women with histologically confirmed breast lesions were retrospectively enrolled. Semiquantitative uptake values (4 methods), the maximum PEM uptake value (PUVmax), and the lesion-to-background (LTB) value (3 methods) were measured. LTB is a ratio of the lesion's PUVmax to the mean background; LTB1, LTB2, and LTB3 (which were calculated on different background) were used to designate the three values measured. Interobserver reliability between two readers for PUVmax and the LTBs was tested using the interobserver correlation coefficient (ICC). The likelihood ratio test was used to evaluate the relationship between ICCs. Receiver operating characteristic (ROC) curves were calculated for all methods. Diagnostic accuracy in differentiating benign tissue from malignant tissue was compared between PUVmax and LTB1. RESULTS: The ICC rate was 0.971 [95 % confidence interval (CI) 0.943-0.986] for PUVmax, 0.873 (95 % CI 0.758-0.935) for LTB1, 0.965 (95 % CI 0.925-0.983) for LTB2, and 0.895 (95 % CI 0.799-0.946) for LTB3. However, there were some technical difficulties in the practical use of LTB2 and LTB3. The likelihood ratio test between PUVmax and LTB1 was statistically significant (p < 0.001). ROC curves of the 4 methods had similar characteristics. The median PUVmax was 1.39 for benign lesions and 3.70 for malignant lesions. LTB1 was 1.92 for benign lesions and 4.78 for malignant lesions. Significant differences (p < 0.001) in both PUVmax and LTB1 were observed between groups. CONCLUSION: Due to its simplicity and reproducibility, PUVmax is superior to LTB as an indicator for PEM in semiquantitative analysis.