Changes in pancreatic exocrine function, fat and fibrosis in diabetes mellitus: analysis using MR imaging.

OBJECTIVE: To evaluate the relationships between hemoglobin A1c (HbA1c) levels with exocrine pancreatic function using cine-dynamic magnetic resonance cholangiopancreatography (MRCP) and the pancreatic parenchyma using fat-suppressed T1 mapping and the proton density fat fraction (PDFF). METHODS: Patients who underwent 3T-MRI and HbA1c measurement were retrospectively recruited. MRI included cine-dynamic MRCP with a spatially selective inversion-recovery (SS-IR) pulse, fat-suppressed Look-Locker T1 mapping and multiecho 3D Dixon-based PDFF mapping. The pancreatic exocrine secretion grade on cine-dynamic MRCP, T1 values, and PDFF were analyzed in non-diabetic (n = 32), pre-diabetic (n = 44) and diabetic (n = 23) groups defined using HbA1c. RESULTS: PDFF was weakly correlation with HbA1c (ρ = 0.30, p = 0.002). No correlations were detected between HbA1c and secretion grade (ρ = - 0.16, p = 0.118) or pancreatic parenchymal T1 (ρ = 0.13, p = 0.19). The secretion grade was comparable between the three groups. The T1 value was higher in diabetic (T1 = 1006.2+/- 224.8 ms) than in non-diabetic (T1 = 896.2+/- 86.3 ms, p = 0.010) and pre-diabetic (T1 = 870.1+/- 91.7 ms, p < 0.010) patients. The PDFF was higher in diabetic (FF = 11.8+/- 8.7 %) than in non-diabetic (FF = 6.8+/- 4.2 %, p = 0.014) patients. CONCLUSION: Pancreatic exocrine function, T1, and FF showed no correlation with HbA1c. Pancreatic T1 and fat fraction is increased in patients with Type 2 diabetes mellitus. ADVANCES IN KNOWLEDGE: This study demonstrates unaffected exocrine function in pre-diabetes and diabetes and confirms that pancreatic parenchymal T1 and FF are increased in patients with diabetes.

Value of 3-T MR imaging in intraductal papillary mucinous neoplasm with a concomitant invasive carcinoma.

OBJECTIVES: To examine the value of 3-T MRI for evaluating the difference between the pancreatic parenchyma of intraductal papillary mucinous neoplasm with a concomitant invasive carcinoma (IPMN-IC) and the pancreatic parenchyma of patients without an IPMN-IC. METHODS: A total of 132 patients underwent abdominal 3-T MRI. Of the normal pancreatic parenchymal measurements, the pancreas-to-muscle signal intensity ratio in in-phase imaging (SIR-I), SIR in opposed-phase imaging (SIR-O), SIR in T2-weighted imaging (SIR-T2), ADC (×10-3 mm2/s) in DWI, and proton density fat fraction (PDFF [%]) in multi-echo 3D DIXON were calculated. The patients were divided into three groups (normal pancreas group: n = 60, intraductal papillary mucinous neoplasm (IPMN) group: n = 60, IPMN-IC group: n = 12). RESULTS: No significant differences were observed among the three groups in age, sex, body mass index, prevalence of diabetes mellitus, and hemoglobin A1c (p = 0.141 to p = 0.657). In comparisons among the three groups, the PDFF showed a significant difference (p < 0.001), and there were no significant differences among the three groups in SIR-I, SIR-O, SIR-T2, and ADC (p = 0.153 to p = 0.684). The PDFF of the pancreas was significantly higher in the IPMN-IC group than in the normal pancreas group or the IPMN group (p < 0.001 and p < 0.001, respectively), with no significant difference between the normal pancreas group and the IPMN group (p = 0.916). CONCLUSIONS: These observations suggest that the PDFF of the pancreas is associated with the presence of IPMN-IC. KEY POINTS: • The cause and risk factors of IPMN with a concomitant invasive carcinoma have not yet been clarified. • The PDFF of the pancreas was significantly higher in the IPMN-IC group than in the normal pancreas group or the IPMN group. • Pancreatic PDFF may be a potential biomarker for the development of IPMN with a concomitant invasive carcinoma.

Evaluation of liver fibrosis using hepatic extracellular volume fraction by contrast-enhanced computed tomography before and after direct-acting antiviral therapy in patients with chronic hepatitis C infection: comparison with serological liver fibrosis markers.

OBJECTIVE: To evaluate time-dependent changes in hepatic extracellular volume (ECV) fraction using contrast-enhanced CT (CECT) and serological liver fibrosis markers, the fibrosis-4 (FIB-4) index and aspartate aminotransferase to platelet ratio index (APRI), before and after direct-acting antiviral therapy (DAA) for hepatitis C virus (HCV) infection. METHODS: 41 HCV-infected patients who achieved sustained virological response (SVR) after DAA (SVR group) and 10 control patients (untreated or unresponsive to treatment) who underwent CECT and serum biochemical tests before or after the first examination/DAA (T1) and at intervals thereafter (T2:<6 months after T1, T3: at 6-12 months, T4: at 12-24 months, and T5:>24 months) were evaluated. RESULTS: In the control group, ECV fractions remained relatively unchanged through the study, and significant differences in FIB-4 index comparisons and APRI comparisons were only seen between the T2 and T4 values (p = 0.046 and p = 0.028, respectively). In the SVR group, ECV fractions were significantly different between T1 and T4 and T1 and T5 (p = 0.046 and 0.022, respectively), and both FIB-4 index and APRI were significantly different between T1 and all other time points (p = 0.017 to p < 0.001 and p = 0.001 to p < 0.001, respectively). CONCLUSION: After DAA, ECV fraction decreased slowly, suggesting an improvement in hepatic fibrosis, while serological liver fibrosis markers decreased immediately, probably due to improvement in hepatic inflammation. ADVANCES IN KNOWLEDGE: ECV fraction has the potential to be a non-invasive biomarker for the assessment of liver fibrosis after direct-acting antiviral therapy.

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.

Kinematic Magnetic Resonance Imaging of the Thorax Using 2-Dimensional Balanced Subsecond Steady-state Free Precession Sequence During Forced Breathing in Comparison With Spirometry.

PURPOSE: The purpose of this article was to investigate the feasibility of kinematic magnetic resonance imaging (MRI) during forced breathing for the assessment of thoracic and diaphragmatic movement and to compare the results of MRI and spirometry to determine the MRI parameters that are predominantly associated with pulmonary function. MATERIALS AND METHODS: Forty-nine healthy volunteers who underwent kinematic MRI using 2-dimensional balanced subsecond steady-state free precession sequence during forced breathing were included. Several items on the MRI were measured and calculated: these were anteroposterior diameter (APD) of the thorax, APD1, ΔAPD, and cross-sectional area (CSA) of the lung field. The results were compared with the results of spirometry. RESULTS: In the comparison between the spirometry results and the MRI kinematic changes, CSA1, ΔCSA, and CSA1% were most significantly correlated with forced expiratory volume in 1 second (right: P<0.001, r=0.814; left: P<0.001, r=0.759); vital capacity (right: P<0.001, r=0.797; left: P<0.001, r=0.780); and forced expiratory volume% in 1 second (right: P<0.001, r=0.530; left: P<0.001, r=0.518), respectively. The APD1 values in the upper position were significantly larger than those in the middle (right: P<0.001; left: P<0.001) and lower (right: P<0.001; left: P<0.001) positions. The ΔAPD values in the upper position were also significantly larger than those in the middle (right: P<0.001; left: P<0.001) and lower (right: P<0.001; left: P<0.001) positions. CONCLUSION: Kinematic MRI with 2-dimensional balanced subsecond steady-state free precession can be used to assess thoracic and diaphragmatic movement during forced breathing. The dynamic changes in CSA correlated well with the results of spirometry.

Evaluation of pancreatic exocrine insufficiency by cine-dynamic MRCP using spatially selective inversion-recovery (IR) pulse: Correlation with severity of chronic pancreatitis based on morphological changes of pancreatic duct.

PURPOSE: To evaluate the correlation between the pancreatic exocrine insufficiency estimated by cine-dynamic MRCP using spatially selective IR pulse and the severity stages (modified Cambridge classification) based on morphological changes of the pancreatic duct in patients with suspected chronic pancreatitis. MATERIALS AND METHODS: Thirty-nine patients with suspected chronic pancreatitis underwent cine-dynamic MRCP with a spatially selective IR pulse. The secretion grading score (5-point scale) based on the moving distance of pancreatic juice inflow on cine-dynamic MRCP was assessed, and compared with the stage of the severity of chronic pancreatitis based on morphological changes of pancreatic duct. RESULT: The stage of the severity of chronic pancreatitis based on morphological changes had significant negative correlations with the secretion grade (r=-0.698, P<0.001). The secretion grading score of stage 4 was significantly lower than stage 1-3 (P<0.001, P=0.002, P=0.025, respectively). In all 19 patients in stage 4, the secretion grading score was <0.70. The secretion grading score of stage 1 was significantly higher than stage 2 and 4 (P=0.019, P<0.001, respectively). In stage 2, the secretion grading score was <0.70 in 8 (89%) of 9 patients showing pancreatic exocrine insufficiency. Conversely, in stage 3, the secretion grading score was >0.70 in 2 (33%) of 6 patients showing normal pancreatic exocrine function. CONCLUSION: It should be noted that the degree of morphological changes of pancreatic duct does not necessarily reflect the severity of pancreatic exocrine insufficiency at cine-dynamic MRCP in stage 2-3 chronic pancreatitis.

Evaluation of renal cortical thickness by non-contrast-enhanced MR imaging with spatially selective IR pulses: comparison between cirrhotic and non-cirrhotic patients.

OBJECTIVE:: To compare renal cortical thicknesses between patients with and without cirrhosis with normal renal function based on serum creatinine using non-contrast-enhanced steady-state, free precession (SSFP) MRI with spatially selective inversion recovery (IR) pulses and to discuss the clinical implications of measuring renal cortical thickness in patients with cirrhosis. METHODS:: 40 patients with and without cirrhosis who had normal renal function based on serum creatinine and underwent non-contrast-enhanced SSFP imaging with spatially selective IR pulses were included. The renal cortical thickness, renal width, renal cortical width ratio, serum creatinine levels and estimated glomerular filtration rates (eGFRs) were compared between cirrhotic and non-cirrhotic groups. RESULTS:: The mean renal cortical thickness was significantly lower in the cirrhotic group (3.6 ± 0.9 mm) than in the non-cirrhotic group (4.9 ± 0.8 mm; p < 0.001). The mean renal cortical width ratio was significantly lower in the cirrhotic group (0.07 ± 0.02) than in the non-cirrhotic group (0.10 ± 0.02; p < 0.001). The mean serum creatinine and mean eGFR did not show significant differences between the two groups. CONCLUSION:: Measurement of renal cortical thickness by means of non-contrast-enhanced SSFP MRI with spatially selective IR pulses may help evaluate renal function accurately in patients with cirrhosis, in whom it may be overestimated by serum creatinine and eGFR. ADVANCES IN KNOWLEDGE:: (1) The renal corticomedullary junction was clearly depicted by non-contrast-enhanced SSFP MRI with spatially selective IR pulses in all patients with and without cirrhosis. (2) The mean renal cortical thickness measured on the optimal SSFP image with spatially selective IR pulses was significantly lower in the cirrhotic group (3.6 ± 1.0 mm) than in the non-cirrhotic group (4.9 ± 0.8 mm) (p < 0.001), although the mean eGFR did not show a significant difference between the two groups.

Postprandial changes in secretory flow of pancreatic juice in the main pancreatic duct: evaluation with cine-dynamic MRCP with a spatially selective inversion-recovery (IR) pulse.

PURPOSE: To evaluate the influence of oral ingestion on the secretory flow dynamics of physiological pancreatic juice within the main pancreatic duct in healthy subjects by using cine-dynamic MRCP with spatially-selective inversion-recovery (IR) pulse non-invasively. MATERIALS AND METHODS: Thirty-eight healthy subjects were investigated. MRCP with spatially-selective IR pulse was repeated every 15 s for 5 min to acquire a total of 20 images (cine-dynamic MRCP). A set of 20 MRCP images was repeatedly obtained before and after liquid oral ingestion every 7 min (including 2-min interval) for 40 min (a total of seven sets). Secretion grade of pancreatic juice on cine-dynamic MRCP was compared before and after oral ingestion using the nonparametric Wilcoxon signed-rank test. RESULTS: Median secretion grades of pancreatic juice at 5 min (score = 2.15), 12 min (score = 1.95) and 19 min (score = 2.05) after ingestion were significantly higher than that before ingestion (score = 1.40) (P = 0.004, P = 0.032, P = 0.045, respectively). Secretion grade of pancreatic juice showed a maximum peak of 2.15 at 5 min after ingestion. Thereafter, the secretion grade of pancreatic juice tended to gradually decline. CONCLUSION: Non-invasive cine-dynamic MRCP using spatially-selective IR pulse showed potential for evaluating postprandial changes in the secretory flow dynamics of pancreatic juice as a physiological reaction. KEY POINTS: • Secretion grade of pancreatic juice at cine-dynamic MRCP after ingestion was evaluated. • Secretion grade was significantly increased within 19 min after liquid meal ingestion. • Secretion grade showed maximum peak of 2.15 at 5 min after ingestion. • Postprandial changes in pancreatic juice flow can be assessed by cine-dynamic MRCP.

Noninvasive investigation of exocrine pancreatic function: Feasibility of cine dynamic MRCP with a spatially selective inversion-recovery pulse.

PURPOSE: To investigate the feasibility of noncontrast-enhanced cine dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatially selective inversion-recovery (IR) pulse for evaluating exocrine pancreatic function in comparison with the N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) test as a pancreatic exocrine function test. MATERIALS AND METHODS: Twenty subjects with or without chronic pancreatitis were included. MRCP with a spatially selective IR pulse was repeated every 15 seconds for 5 minutes to acquire a total of 20 images (cine-dynamic MRCP). The median and mean frequency of the observation (the number of times) and the moving distance (mean secretion grading scores) of pancreatic juice inflow on cine-dynamic MRCP were compared with a BT-PABA test. RESULTS: The urinary PABA excretion rate (%) had significant positive correlations with both the mean secretion grade (r = 0.66, P = 0.002) and frequency of secretory inflow (r = 0.62, P = 0.004) in cine dynamic MRCP. Both the mean frequency of observations of pancreatic secretory inflow (1.4 ± 1.6 times vs. 14.3 ± 4.2 times, P < 0.001) and the mean secretion grade (grade = 0.16 ± 0.24 vs. grade = 1.81 ± 0.81, P < 0.001) was significantly lower in the chronic pancreatitis group than in the normal subject group. CONCLUSION: Cine dynamic MRCP with a spatially selective IR pulse may have potential for estimating the pancreatic exocrine function noninvasively as a substitute for the BT-PABA test.

Traumatic hypovolemic shock revisited: the spectrum of contrast-enhanced abdominal computed tomography findings and clinical implications for its management.

Hypovolemic shock is often seen in patients with severe blunt trauma who have suffered from blood circulation inadequate to maintain oxygen delivery to multiple organs. The early recognition and prompt management of hypovolemic shock in patients with multiple injuries are mandatory to improving prognosis and patient conditions. The diagnostic accuracy of computed tomography (CT) as a primary diagnostic tool is well established. The abdominal organs show several common and classic appearances on contrast-enhanced CT in patients with trauma. The hypovolemic shock complex is reported in the previous literature as decreased enhancement of the viscera, increased mucosal enhancement and luminal dilation of the small bowel, mural thickening and fluid-filled loops of the small bowel, the halo sign and flattening of the inferior vena cava, reduced aortic diameter, and peripancreatic edema. However, there have been controversial CT reports with contradictory appearances. Physicians understanding these findings could prompt alternative approaches to the early assessment and management of hypovolemic shock. The aim of this article is to illustrate common and well-known abdominal CT features in patients with traumatic hypovolemic shock, to discuss controversial CT signs in the pancreas and adrenal gland, and to describe CT findings' clinical implications when managing hypovolemic shock.

Prognosis of small hepatocellular nodules detected only at the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging as hypointensity in cirrhosis or chronic hepatitis.

PURPOSE: To evaluate the prognosis of "strict" high-risk nodules (small hepatocellular nodules detected only in the hepatobiliary phase of initial Gd-EOB-DTPA-enhanced MR examination) in patients with cirrhosis or chronic hepatitis. METHODS AND MATERIALS: The study included thirty-three patients with 60 "strict" high-risk nodules showing hypointensity at the hepatobiliary phase that was undetectable at the vascular phase and other conventional sequences of initial Gd-EOB-DTPA-enhanced MR imaging. These nodules were observed on follow-up MR examinations until hypervascularity was detected. The potential predictive factors for hypervascular transformation were compared between two groups (group A showing hypervascular transformation, group B not showing hypervascularization). RESULTS: Ten (16.7 %) of 60 "strict" high-risk nodules showed hypervascular transformation during follow-up periods (group A). The growth rates of the nodules in group A (6.3 ± 4.5 mm/year) were significantly higher than those in group B (3.4 ± 7.2 mm/year) (p = 0.003). Additionally, the median observation period in group A (177.5 ± 189.5 day) was significantly shorter than in group B (419 ± 372.2 day) (p = 0.045). The other predictive factors were not significantly correlated with hypervascularization. CONCLUSIONS: Subsets of "strict" high-risk nodules showed hypervascular transformation during follow-up periods in association with increased growth rates, indicating that nodule growth rate is an important predictive factor for hypervascularization. KEY POINTS: • "Strict" high-risk nodules are defined as hepatocellular nodules detected only in the hepatobiliary-phase. • Subsets of "strict" high-risk nodules showed hypervascular transformation during follow-up periods. • Increased growth rate is an important predictive factor for hypervascular transformation. • Management of patients with "strict" high-risk nodules becomes more appropriate.

Age-related change of the secretory flow of pancreatic juice in the main pancreatic duct: evaluation with cine-dynamic MRCP using spatially selective inversion recovery pulse.

OBJECTIVE: The purpose of this study is to evaluate age-related changes in the secretory flow of pancreatic juice in the main pancreatic duct noninvasively by means of nonpharmacologic cine-dynamic MRCP using spatially selective inversion recovery (IR) pulse. MATERIALS AND METHODS: Fifty-three subjects without a history of pancreatic disease were included. Four-second breath-hold MRCP using spatially selective IR pulse was performed every 15 seconds during 5 minutes (acquiring a total of 20 images) in cine-dynamic fashion. The secretion grade was classified into five grades by the distance of pancreatic juice inflow within the tagged area. The mean secretion grade and the frequency of secretion in cine-dynamic MRCP were compared among three age-range groups (group 1, < 40 years; group 2, 40-70 years; and group 3, > 70 years). Statistical analysis was performed using Spearman rank correlation coefficient and Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The secretion grade and the frequency of secretion were significantly reduced with aging (r = -0.77, p < 0.001; and r = -0.74, p < 0.001, respectively). The mean secretion grade and the frequency of secretion were significantly lower in group 3 than in group 2 (mean grade, 0.36 vs 1.48, p = 0.001; and 4.8 vs 11.9 times, p = 0.001) and were lower in group 2 than in group 1 (mean grade, 1.48 vs 2.48, p < 0.001; and 11.9 vs 16.2 times, p = 0.011). CONCLUSION: Cine-dynamic MRCP using spatially selective IR pulse was able to show the age-related decrease of the secretory flow of pancreatic juice in the main pancreatic duct visually and noninvasively.

Renal corticomedullary differentiation by non-contrast-enhanced MR imaging with a spatially selective IR pulse at various inversion times: comparison with fast asymmetric spin echo (FASE) and steady-state free-precession (SSFP).

We compared visualization of corticomedullary differentiation between fast asymmetric spin echo (FASE) and steady-state free precession (SSFP) combined with spatially selective inversion recovery (IR) pulse and optimal inversion time (TI). Though the corticomedullary contrast ratio was higher in FASE than SSFP images, visualization of corticomedullary differentiation was significantly better in SSFP images than FASE images obtained with spatially selective IR pulses and optimal TI.

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.

Accumulation of Bile in the Gallbladder: Evaluation by means of Serial Dynamic Contrast-Enhanced Magnetic Resonance Cholangiography with Gadolinium Ethoxybenzyl Diethylenetriaminepentaacetic Acid.

The aim of this study was to evaluate the process of biliary excretion of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) into the biliary tract and to assess the accumulation patterns in the gallbladder using MR cholangiography obtained with Gd-EOB-DTPA which is a liver-specific hepatobiliary contrast agent. Seventy-five patients underwent Gd-EOB-DTPA enhanced MR imaging. Serial multiphasic hepatobiliary phase imaging was qualitatively reviewed to evaluate the process of the biliary excretion of contrast agent into the bile duct and the gallbladder. The accumulation pattern of contrast agent into gallbladder was classified into two groups (group 1 = orthodromic type and group 2 = delayed type). Furthermore, the results in differences of the presence of T1 hyperintense bile or sludge of gallbladder, gall stones, wall thickening of gallbladder, chronic liver disease, and liver cirrhosis between two groups were compared. Forty-eight of 75 patients (64%) were included in group 1, and remaining 27 (36%) were in group 2. The frequency of the presence of T1 hyperintense bile or sludge of gallbladder was significantly higher in patients with group 2 than that in patients with group 1 (P = 0.041). MR cholangiography obtained with Gd-EOB-DTPA showed that there may be an association between the biliary accumulation pattern in the gallbladder and the pathological condition.

Hypointense hepatocellular nodules on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI: can increasing the flip angle improve conspicuity of lesions?

PURPOSE: To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs). MATERIALS AND METHODS: A total of 95 patients with chronic liver disease who underwent Gd-EOB-DTPA-enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver-to-lesion contrast-to-phantom ratios (CPR) and lesion conspicuity (LCS) were assessed. RESULTS: In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001). CONCLUSION: In the evaluation of hypointense hepatocellular nodules on HP of Gd-EOB-DTPA-enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°.

Simple Method for evaluating the degree of liver parenchymal enhancement in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging.

PURPOSE: To establish a simple method to evaluate the degree of liver parenchymal enhancement in the hepatobiliary phase (HP) of gadoxetic acid-enhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: Subjects comprised 75 patients with or without chronic liver disease who underwent gadoxetic acid-enhanced MRI and indocyanine green retention at 15 minutes (ICG-R15). HP images were used for data analysis. In the quantitative evaluation, liver-to-phantom signal intensity (SI) ratio (LPR), liver-to-portal vein SI ratio (LPVR), and liver-to-kidney SI ratio (LKR) were calculated. In qualitative visual assessment, liver-to-portal vein contrast (LPVC) and liver-to-kidney contrast (LKC) were assessed using a 5-point scale (1, hyperintense; 2, slightly hyperintense; 3, isointense; 4, slightly hypointense; 5, hypointense). Statistical evaluations included the Spearman's rank correlation test. RESULTS: LPVC and LKC correlated significantly with LPR (ρ = -0.445, P < 0.001; ρ = -0.576, P < 0.001, respectively). LPVC and LKC showed significant correlations with LPVR and LKR (ρ = -0.659, P < 0.001; ρ = -0.674, P < 0.001, respectively). In addition, LPVC and LKC correlated significantly with ICG-R15 (ρ = 0.696, P < 0.001; ρ = 0.795, P < 0.001, respectively). CONCLUSION: LPVC and LKC can be used as simple visual indicators to objectively assess the degree of liver parenchymal enhancement on HP of gadoxetic acid-enhanced MRI.