Park SH, et al. Korean J Radiol. 2020 Jul;21(7):812-828. https://doi.org/10.3348/kjr.2020.0483

To evaluate the association between Non-alcoholic fatty liver disease (NAFLD) with renal stone disease detected on computed tomography (CT). A total 1812 patients who underwent abdomen-pelvis CT in July 2015 were included in this study. The inclusion criteria for NAFLD were as follows: (i) lower average Hounsfield unit (HU) of hepatic right lobe, left medial and lateral segment when compared with that of spleen, (ii) patients who having urolithiasis in kidneys, ureters and urinary bladder, and (iii) patients underwent abdomen-pelvis CT including noncontrast image. The statistical significance of the association between NAFLD and renal stone disease was assessed using Chi Square Test. The Odds ratios and 95% CI were calculated to assess the propensity of renal stones disease for NAFLD by using Logistic Regression analysis. The frequency of renal stone disease in patients with NAFLD was higher approximately 19% than those who having renal stone disease without NAFLD. In addition, the presence of NAFLD was linked with renal stone disease showing that detection rate of renal stone disease in patients with NAFLD was markedly high (odds ratio: 5, 95% CI, 3-8.2) (p < 0.05) in multivariate analysis. The presence of significant association between NAFLD with renal stone disease and NAFLD may be considered to be an independent variable as a risk factor for renal stone disease.

Background: As there is increased concern over the radiation exposure particularly in adolescents and young adults, computed tomography (CT) dose reduction is needed in the diagnosis of acute appendicitis. Purpose: To evaluate the optimal strength of sinogram affirmed iterative reconstruction (SAFIRE) to obtain the best image quality on a 30-mAs applied low-dose CT (LDCT _30mAs ) and to compare the diagnostic performances of the LDCT _30mAs with different SAFIRE strengths with that of the 100-mAs applied LDCT (LDCT _100mAs ) for the diagnosis of acute appendicitis. Material and Methods: A total of 102 consecutive patients (47 men, 55 women; mean age, 41.2 years; range, 15–82 years) with right lower quadrant pain underwent abdominal-pelvic CT, consisting of arterial phase LDCT _100mAs and portal venous phase LDCT _30mAs under a fixed 120 kV. LDCT _30mAs images were reconstructed separately with five strength levels (S1–S5). Two blinded radiologists recorded scores for the subjective image quality of the LDCT _30mAs dataset (S0–S5) and confidence scores for the diagnosis of acute appendicitis on each dataset and LDCT _100mAs . CT image noise was measured for each set. Results: The study population consisted of 58 patients with confirmed appendicitis and 44 without appendicitis. There was no significant difference in diagnostic performance between LDCT _100mAs and LDCT _30mAs with any strength for both readers (AUC for reader 1, LDCT _30mAs with S0–S5 = 0.97, LDCT _100mAs = 0.93, P = 0.0936; for reader 2, LDCT _30mAs with S0–S5 = 0.96, LDCT _100mAs = 0.97, P = 0.128). The measured noise decreased as the strength increased from S0 to S5 (mean, 20.8 > 17.7 > 15.6 > 13.5 > 11.5 > 9.5, P < 0.0001). However, overall subjective image quality on S3 was better than the other strengths for both readers (S0 < S1 < S2 < S3 > S4 > S5, P < 0.0001). Conclusion: Although measured noise declined as SAFIRE strength increased, S3 seems optimal for the best subjective image quality on LDCT _30mAs . The diagnostic performance of LDCT _30mAs with any strength is comparable to that of LDCT _100mAs for the diagnosis of acute appendicitis.

Background: To evaluate the association between various radiologic-pathologic findings and oncogenic Kirsten-ras (KRAS) mutation in patients with primary rectal cancer. Methods: Seventy-five patients with primary rectal cancer who had undergone rectal magnetic resonance imaging (MRI) were included. The rectal MRI consisted of T2-weighted images in three planes, pre- and post-contrast-enhanced T1-weighted images, and axial diffusion-weighted images (b factors, 0, 1,000 s/mm²). Two radiologists reviewed the MRI scans and measured the axial and longitudinal tumor lengths (LTLs), apparent diffusion coefficient (ADC), and relative contrast enhancement [signal intensity (SI) difference of tumor on pre- and post-contrast T1WI/SI of tumor on pre-contrast T1WI]. The associations among the qualitative data (tumor stage, node stage, lymphatic invasion, venous invasion, and perineural invasion), quantitative data (tumor length, ADC, relative contrast enhancement) and KRAS mutations were statistically analyzed by Fisher’s exact test for the qualitative data and by the Mann-Whitney U test for the quantitative data. An area under receiver operating characteristic curve (AUC) was considered as the diagnostic performance for the prediction of KRAS mutation. Molecular-biologic results served as the reference standard. Results: The ratio of axial to LTL in the KRAS-mutant group (n=41) was higher than that in the wild-type group (n=34) (0.29±0.15; 0.22±0.08, P=0.0117). The AUC was 0.640 (95% CI, 0.520 to 0.747, P=0.0292) with an estimated maximum accuracy of 64%. The mean ADC of the mutant group was not significantly different from that of the wild-type group [(0.95±0.17)×10⁻³ mm²/s; (0.96±0.17)×10⁻³ mm²/s, P=0.6505]. The relative contrast enhancement showed no significant difference between the two groups (1.66±0.93, 1.35±0.84, P=0.1581). The other qualitative findings also did not show any significant difference (P>0.05). Conclusions: The ratio of axial to LTL showed a significant difference according to KRAS mutation in patients with primary rectal cancer. However, it showed a low accuracy of 64% for prediction of KRAS mutation.

Dynamic contrast-enhanced magnetic resonance imaging for risk stratification in patients with prostate cancer Hyungin Park, Seung Ho Kim, Joo Yeon Kim