A quantitative analysis of progressive fibrosing interstitial lung disease on computed tomography for the assessment of decreased vital capacity.

BACKGROUND: The results of a quantitative analysis of computed tomography (CT) of interstitial lung disease (ILD) using a computer-aided detection (CAD) technique were correlated with the results of pulmonary function tests. PURPOSE: To evaluate the correlation between a quantitative analysis of CT of progressive fibrosing interstitial lung disease (PF-ILD) including idiopathic pulmonary fibrosis (IPF) and non-IPF, which can manifest progressive pulmonary fibrosis and the vital capacity (VC), and to identify indicators for the assessment of a decreased VC. MATERIAL AND METHODS: A total of 73 patients (46 patients with IPF and 27 patients with non-IPF) were included in this study. Associations between the quantitative analysis of CT and the %VC using a CAD software program were investigated using Spearman's rank correlation and a logistic regression analysis. The appropriate cutoff vale for predicting a decreased VC was determined (%VC <80) and the area under the curve (AUC) was calculated. RESULTS: A multiple logistic regression analysis showed that the total extent of interstitial pneumonia on CT was a significant indicator of a decreased VC (P = 0.0001; odds ratio [OR]=1.15; 95% confidence interval [CI]=1.06-1.27 in IPF and P = 0.0025; OR=1.16; 95% CI=1.03-1.30 in non-IPF). The cutoff values of the total extent of interstitial pneumonia in IPF and non-IPF for predicting a decreased VC were determined to be 23.3% and 21.5%, and the AUCs were 0.83 and 0.91, respectively. CONCLUSION: A quantitative analysis of CT of PF-ILD using a CAD software program could be useful for predicting a decreased VC.

Impact of fat on the apparent T1 value of the liver: assessment by water-only derived T1 mapping.

OBJECTIVES: To determine the impact of fat on the apparent T1 value of the liver using water-only derived T1 mapping. METHODS: 3-T MRI included 2D Look-Locker T1 mapping and proton density fat fraction (PDFF) mapping. T1 values of the liver were compared among T1 maps obtained by in-phase (IP), opposed-phase (OP), and Dixon water sequences using paired t-test. The correlation between T1 values of the liver on each T1 map and PDFF was assessed using Spearman correlation coefficient. The absolute differences between T1 value of the liver on Dixon water images and that on IP or OP images were also correlated with PDFF. RESULTS: One hundred sixty-two patients (median age, 70 [range, 24-91] years, 90 men) were retrospectively evaluated. The T1 values of the liver on each T1 map were significantly different (p < 0.001). The T1 value of the liver on IP images was significantly negatively correlated with PDFF (r = - 0.438), while the T1 value of the liver on OP images was slightly positively correlated with PDFF (r = 0.164). The T1 value of the liver on Dixon water images was slightly negatively correlated with PDFF (r = - 0.171). The absolute differences between T1 value of the liver on Dixon water images and that on IP or OP images were significantly correlated with PDFF (r = 0.606, 0.722; p < 0.001). CONCLUSION: Fat correction for the apparent T1 value by water-only derived T1 maps will be helpful for accurately evaluating the T1 value of the liver. CLINICAL RELEVANCE STATEMENT: Fat-corrected T1 mapping of the liver with the water component only obtained from the 2D Dixon Look-Locker sequence could be useful for accurately evaluating the T1 value of the liver without the impact of fat in daily clinical practice. KEY POINTS: • The T1 values of the liver on the conventional T1 maps are significantly affected by the presence of fat. • The apparent T1 value of the liver on water-only derived T1 maps would be slightly impacted by the presence of fat. • Fat correction for the apparent T1 values is necessary for the accurate assessment of the T1 values of the liver.

Assessment of gastric wall structure using ultra-high-resolution computed tomography.

PURPOSE: To evaluate the image quality of ultra-high-resolution CT (U-HRCT) in the comparison among four different reconstruction methods, focusing on the gastric wall structure, and to compare the conspicuity of a three-layered structure of the gastric wall between conventional HRCT (C-HRCT) and U-HRCT. METHOD: Our retrospective study included 48 patients who underwent contrast-enhanced U-HRCT. Quantitative analyses were performed to compare image noise of U-HRCT between deep-learning reconstruction (DLR) and other three methods (filtered back projection: FBP, hybrid iterative reconstruction: Hybrid-IR, and Model-based iterative reconstruction: MBIR). The mean overall image quality scores were also compared between the DLR and other three methods. In addition, the mean conspicuity scores for the three-layered structure of the gastric wall at five regions were compared between C-HRCT and U-HRCT. RESULTS: The mean noise of U-HRCT with DLR was significantly lower than that with the other three methods (P < 0.001). The mean overall image quality scores with DLR images were significantly higher than those with the other three methods (P < 0.001). Regarding the comparison between C-HRCT and U-HRCT, the mean conspicuity scores for the three-layered structure of the gastric wall on U-HRCT were significantly better than those on C-HRCT in the fornix (5 [5-5] vs. 3.5 [3-4], P < 0.001), body (4 [3.25-5] vs. 4 [3-4], P = 0.039), angle (5 [4-5] vs. 3 [2-4], P < 0.001), and antral posterior (4 [3.25-5] vs. 2 [2-4], P < 0.001), except for antral anterior (4 [3-5] vs. 3 [3-4], P = 0.230) CONCLUSION: U-HRCT using DLR improved the image noise and overall image quality of the gastric wall as well as the conspicuity of the three-layered structure, suggesting its utility for the evaluation of the anatomical details of the gastric wall structure.

Assessment of the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase and hepatic signal changes in free-breathing continuous multiphasic dynamic EOB-MRI.

PURPOSE: To investigate the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase (HBP) and the contrast enhancement parameters based on the data of continuous signal changes in free-breathing multiphasic dynamic EOB-MR imaging using a compressed sensing (CS) and the self-gating technique, and to clarify which contrast enhancement parameters are useful for estimating the hepatic enhancement effect in the HPB. METHOD: This study included 96 patients. The contrast enhancement ratio (CER) of the liver parenchyma from phase x to phase y was calculated as follows: CERy-x: (SIy -SIx)/SIx. The gradient of the regression line (GRL) was also calculated. Patients can be divided into two groups with sufficient or insufficient liver enhancement in the HBP, then each parameter was compared between these two groups. RESULTS: In the analysis of the arterioportal phases, CER7-pre in the sufficient HBP enhancement group was significantly higher than that in the insufficient HBP enhancement group (0.50 vs 0.44, p < 0.001). Regarding 5 min early hepatocyte phase (phases 1-28) analysis, significant differences were observed in CER28-pre, CER28-7 and Gradient28-7 between the two groups (0.64 vs 0.47, 0.10 vs 0.03, 1.27 vs 0.27, all p < 0.001). For the strength of correlation, CER7-pre, CER28-pre, CER28-7, and GRL28-7 had higher correlation coefficients, compared with the blood sampling data. CONCLUSION: CER in the arterio-portal phase and 5 min early hepatocyte phase had significant correlation with hepatic contrast enhancement effects in the 20 min HBP, suggesting that sufficient 20 min HBP enhancement may be estimated by the CER in the portal phase and 5 min early hepatocyte phase.

Influence of cholecystectomy on the flow dynamic pattern of bile in the extrahepatic bile duct: Assessment by cine-dynamic MRCP with spatially-selective IR pulse.

PURPOSE: To evaluate the influence of cholecystectomy on the flow dynamic pattern of bile in the extrahepatic bile duct by using cine-dynamic MRCP with spatially-selective inversion-recovery (IR) pulse non-invasively. MATERIALS AND METHODS: 56 patients with cholecystectomy and 48 control subjects without cholecystectomy who underwent cine-dynamic MRCP with spatially-selective IR pulse at 1.5 T or 3 T (TR/TE, 4000 msec/500 msec; echo train spacing, 6.5 msec; echo train length, 172; section thickness, 50 mm; matrix, 320 × 320; field of view, 320 × 320 mm; bandwidth, 488 Hz; and inversion time, 2200 msec). In cine-dynamic MRCP, IR pulse with 20 mm width was placed on the common bile duct (CBD) to evaluate the movement of bile (antegrade and reversed bile flow). Cine-dynamic MRCP imaging was scanned every 15 s (imaging, 4 s; rest, 11 s) during 5 min to acquire a series of single-shot images (a total of 20 images). The frequency that antegrade or reversed bile flow was observed in the extrahepatic bile duct, and 5-point grading score based on the moving distance of antegrade or reversed bile flow were compared between the groups. Both groups were compared using the χ2 and Mann-Whitney U tests (P < 0.05 considered significant). RESULTS: Antegrade bile flow was observed more frequently in the cholecystectomy group than in the non-cholecystectomy group (5.1 times vs. 2.8 times, P = 0.008). Mean grading score of antegrade bile flow was significantly greater in the cholecystectomy group than in the non-cholecystectomy group (mean grade, 0.33 vs 0.21; P = 0.014). Regarding reversed bile flow, there were no significant differences in the frequency and grading score between cholecystectomy group and non-cholecystectomy group. CONCLUSION: Antegrade bile flow was observed more frequently and predominantly in patients after cholecystectomy in cine-dynamic MRCP with spatially-selective IR pulse while reversed bile flow was observed equivalently.

Symptoms that are associated with decreased pancreatic enzyme flow: MRCP assessment.

BACKGROUND: Pancreatic exocrine insufficiency is one of the causes of malabsorption syndrome. In many cases of malabsorption syndrome, pancreatic exocrine insufficiency can be treated with pancreatic enzyme replacement therapy. Therefore, it is important to detect pancreatic endocrine insufficiency as early and accurately as possible. Recent studies have shown that cine-dynamic MR cholangiopancreatography (MRCP) may be useful to evaluate pancreatic exocrine function PURPOSE: To identify abdominal symptoms that suggest decreased flow of pancreatic enzyme secretion for which cine-dynamic MRCP should be performed to diagnose pancreatic exocrine insufficiency. STUDY TYPE: Prospective. POPULATION: In all, 111 patients with various types of abdominal symptoms. FIELD STRENGTH/SEQUENCE: 5 T or 3 T, MRCP with spatially selective inversion recovery pulse (cine-dynamic MRCP). ASSESSMENT: Cine-dynamic MRCP was performed and an 18-question clinical questionnaire on abdominal symptoms was administered. The secretion grade derived from cine-dynamic MRCP was compared between those answering "yes" and "no" for all 18 items STATISTICAL TESTS: Univariate analysis and further analyzed using multiple regression analysis. The associations between the secretion grade and the items in the clinical questionnaire were analyzed by univariate analysis and further analyzed using multiple regression analysis. RESULTS: The following three items showed significantly negative correlations with secretion grade: Q9, Does your rectal gas smell foul? (ß = -0.44, P = 0.001); Q13, Is stool quantity large? (ß = -0.41, P = 0.001); and Q18, Are your stools soft? (ß = -0.53, P < 0.001). No significant correlations with exocrine pancreatic function measured by cine-dynamic MRCP were seen for the remaining 15 abdominal symptom items. DATA CONCLUSION: Abdominal symptoms that suggest decreased flow of pancreatic enzyme secretion were foul rectal gas, large stool, and soft stool. Pancreatic exocrine insufficiency due to decreased pancreatic enzyme flow may be suspected in patients with these abdominal symptoms. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:417-423.

Assessment of clinical and magnetic resonance imaging features of de novo hypervascular hepatocellular carcinoma using gadoxetic acid-enhanced magnetic resonance imaging.

AIM: To clarify the clinical and magnetic resonance imaging (MRI) features of de novo hypervascular hepatocellular carcinoma (HCC) using serial gadoxetic acid-enhanced MRI. METHODS: The institutional review board approved this retrospective study. After review of 1007 MRI examinations in 240 patients with chronic liver disease, 17 newly developed hypervascular HCCs in 16 patients detected by follow-up from initial MRI examination without hepatocellular nodules were evaluated. The clinical and MRI findings such as previous treatment history for HCC, period to hypervascular HCC onset, presence or absence of hypovascular hypointense nodules on hepatobiliary phase before hypervascularization, and intralesional fat component were recorded or evaluated. Statistical evaluations included Fisher's exact test, χ2 -test, and Mann-Whitney U-test. RESULTS: In 17 HCCs, 12 (71%) were de novo hypervascular HCC without showing hypovascular hypointense nodule on hepatobiliary phase before hypervascularization (de novo group) and 5 (29%) were hypervascularized HCC developed during multistep hepatocarcinogenesis (multistep group). The incidence of previous treatment history for HCC in the de novo group (91%) was significantly higher than that in the multistep group (20%) (P = 0.013). The duration to hypervascular HCC onset from initial examination was shorter in the de novo group (mean, 291 days) than in the multistep group (mean, 509 days) (P = 0.035). The incidence of fat-containing lesion in the de novo group (0%) was lower than that in the multistep group (40%) (P = 0.074). CONCLUSION: De novo hypervascular HCC is characterized by rapid growth, patients with previous treatment history for HCC, and lack of intralesional fat, compared to hypervascular HCC with multistep progression.

Assessment of physiologic bile flow in the extrahepatic bile duct with cine-dynamic MR cholangiopancreatography and a spatially selective inversion-recovery pulse.

PURPOSE: To determine the feasibility of directly and noninvasively visualizing physiologic bile flow in the extrahepatic bile duct by means of nonpharmacologic cine-dynamic magnetic resonance (MR) cholangiopancreatography with a spatially selective inversion-recovery (IR) pulse and assess the flow dynamic pattern of bile in the extrahepatic bile duct. MATERIALS AND METHODS: The institutional review board approved this retrospective study and waived the need for informed consent. Thirty-five patients without known pancreatobiliary diseases and 11 patients with dilatation of the extrahepatic bile duct were included. Cine-dynamic MR cholangiopancreatography with a spatially selective IR pulse was performed by imaging every 15 seconds over a 5-minute interval (20 images acquired total). The images were evaluated for the visualization of bile flow, the frequency that bile flow was observed in the extrahepatic bile duct, and the distance the bile moved within the area of the IR pulse. Statistical analysis was performed by using Spearman rank correlation coefficient and Mann-Whitney U tests. RESULTS: Antegrade bile flow was observed in 29 of 35 patients (83%) in the nondilated group. Bile flow was observed much more frequently in the nondilated group than in the dilated group (4.4 times vs 1.8 times, P = .029). The distance that bile moved forward within the area of the IR pulse was significantly greater in the nondilated group than in the dilated group (mean grade, 0.44 vs 0.14; P = .033), suggesting stagnation or slowdown of antegrade bile flow in patients with biliary dilatation. Reversed bile flow was also observed in 26 of 35 patients (74%) in the nondilated group without biliary diseases. CONCLUSION: Nonpharmacologic cine-dynamic MR cholangiopancreatography with a spatially selective IR pulse allows direct and noninvasive visualization of bile flow in the extrahepatic bile duct, demonstrating that reversed bile flow is a physiologic phenomenon.

Modified Blalock-Taussig shunt patency for pulmonary atresia: assessment with electron beam CT.

PURPOSE: The purpose of this work was to evaluate electron beam CT (EBCT) for the noninvasive assessment of modified Blalock-Taussig (BT) shunt patency in patients with pulmonary atresia. METHOD: Five infants and children with pulmonary atresia and modified BT shunts underwent contrast-enhanced EBCT. Modified BT shunts from the subclavian artery to the pulmonary artery were performed to improve the pulmonary blood flow. Electrocardiogram (ECG)-triggered EBCT was obtained with a 100 ms exposure, 3 mm section thickness, and 2 mm table feed after intravenous administration of contrast material. Three-dimensional (3D) or maximum intensity projection (MIP) EBCT images were compared with conventional angiography. The visibility of modified BT shunts was graded and recorded with use of a four-point scale. RESULTS: Satisfactory visualization was achieved in both 3D and MIP EBCT images to evaluate modified BT shunt patency. CONCLUSION: Contrast-enhanced 3D or MIP EBCT imaging with ECG trigger may be used as an effective substitute to evaluate modified BT shunts with low radiation dose exposure.