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.

A quantitative analysis of long-term follow-up computed tomography of idiopathic pulmonary fibrosis: the correlation with the progression and prognosis.

BACKGROUND: Quantitative analyses of computed tomography (CT) images using computer-aided detection (CAD) are correlated with visual assessments and pulmonary function test findings and might be useful for predicting the prognosis of patients with idiopathic pulmonary fibrosis (IPF). PURPOSE: To evaluate the association between the quantitative analysis of long-term follow-up CT of IPF and the progression and prognosis. MATERIAL AND METHODS: A total of 48 patients with IPF who received over one year of follow-up CT were included in this study. The results of quantitative analyses (emphysema, ground-glass attenuation [GGA], consolidation, reticulation, and honeycombing) using a CAD software program of initial and follow-up CT findings were evaluated, and the association with the progression of the total lesion of IPF and prognosis using Spearman's rank correlation and Cox regression analyses was considered. RESULTS: Results of quantitative analyses of consolidation, reticulation, honeycombing, and the total lesion on initial CT were correlated with progressive changes in the total lesion of IPF per year (r = 0.4375, 0.4128, 0.4649, and 0.4095, respectively). The results of quantitative analyses of honeycombing (hazard ratio [HR] = 1.40, 95% confidence interval [CI] = 1.03-1.89, P = 0.0314) and GGA (HR = 0.85, 95% CI = 0.72-0.99, P = 0.0384) at initial CT were prognostic factors according to a multivariate Cox regression analysis. CONCLUSION: The quantitative analysis of honeycombing using a CAD software program of CT findings may be useful for predicting the progression and prognosis of patients with IPF.

Evaluation of diffusion-weighted magnetic resonance imaging of the rectal cancers: comparison between modified reduced field-of-view single-shot echo-planar imaging with tilted two-dimensional radiofrequency excitation pulses and conventional full field-of-view readout-segmented echo-planar imaging.

PURPOSE: To evaluate the image quality qualitatively and quantitatively, as well as apparent diffusion coefficient (ADC) values of modified reduced field-of-view diffusion-weighted magnetic resonance imaging (MRI) using spatially tailored two-dimensional radiofrequency pulses with tilted excitation plane (tilted r-DWI) based on single-shot echo planar imaging (SS-EPI) compared with full-size field-of-view DWI (f-DWI) using readout segmented (RS)-EPI in patients with rectal cancer. MATERIALS AND METHODS: Twenty-two patients who underwent an MRI for further evaluation of rectal cancer were included in this retrospective study. All MR images were analyzed to compare image quality, lesion conspicuity, and artifacts between f-DWI with RS-EPI and tilted r-DWI with SS-EPI. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and ADC values were also compared. The Wilcoxon signed-rank test or paired t test was performed to compare the qualitative and quantitative assessments. RESULTS: All image quality scores, except aliasing artifacts, were significantly higher (p < 0.01 for all) in tilted r-DWI than f-DWI with RS-EPI. CNR in tilted r-DWI was significantly higher than in f-DWI with RS-EPI (p < 0.01), while SNR was not significantly different. Regarding the ADC values, no significant difference was observed between tilted r-DWI and f-DWI with RS-EPI (p = 0.27). CONCLUSION: Tilted r-DWI provides a better image quality with fewer artifacts and higher rectal lesion conspicuity than f-DWI with RS-EPI, indicating the feasibility of this MR sequence in evaluating rectal cancer in clinical practice.

Three-Dimensional (3D) Breath-Hold Zoomed MR Cholangiopancreatography (MRCP): Evaluation of Additive Value to Conventional 3D Navigator Triggering MRCP in Patients With Branch Duct Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: To resolve drawbacks of navigator triggering (NT) three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP), several approaches were proposed to obtain 3D MRCP within a single breath-hold (BH). However, reduced field-of-view technique in the phase-encoding direction combined with two-dimensional spatially selective radiofrequency excitation pulses has not yet been applied to 3D BH MRCP. PURPOSE: To investigate the feasibility and the complementary value of 3D BH zoomed MRCP to conventional 3D NT MRCP in patients with branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas. STUDY TYPE: Retrospective. POPULATION: A total of 221 patients (116 male and 105 female, median age 73 years) with BD-IPMNs. FIELD STRENGTH/SEQUENCE: 3.0 T/3D turbo spin echo ASSESSMENT: MR images were analyzed by three radiologists (R.M., H.O., M.T., with 1, 13, and 17 years of experience) to compare blurring and motion artifacts, background suppression, visualization of main pancreatic duct (MPD), conspicuity of BD-IPMN, and overall image quality. STATISTICAL TESTS: Wilcoxon-signed rank, Mann-Whitney U, chi-squared or Fisher's exact tests (P < 0.05). RESULTS: Image quality was significantly higher on 3D NT MRCP images than on 3D BH zoomed MRCP (median (interquartile range); background suppression, 4 (4-4) vs. 3 (3-4); visualization of MPD, 4 (3-4) vs. 4 (3-4), conspicuity of BD-IPMN, 4 (3-4) vs. 3 (3-4); and overall image quality, 3 (3-4) vs. 3 (3-3)). However, in 32 (14%) patients, 3D NT MRCP showed a score of 1 or 2 in overall image quality. Regarding the conspicuity of BD-IPMN, a conspicuity score of 1 or 2 was rendered in 31 (14%) patients in 3D NT MRCP group. Conversely, 3D BH zoomed MRCP showed a score of 3 or 4 in 29 (94%) of these 31 patients. DATA CONCLUSION: 3D BH zoomed MRCP plays a complementary role to 3D NT MRCP, and may improve the conspicuity of BD-IPMNs in patients with irregular breathing pattern. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Pancreatobiliary Flow Dynamics: Association Between Bile and Pancreatic Juice Evaluated With Cine-Dynamic Magnetic Resonance Cholangiopancreatography Using Spatially Selective Inversion Recovery Pulse.

BACKGROUND: The physiological flow patterns and the reciprocal relationship between pancreatic juice and bile excretion dynamics have not been clearly elucidated by imaging. PURPOSE: To assess the physiological flow patterns of bile and pancreatic juice simultaneously in order to clarify the pancreatobiliary flow dynamics using cine-dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatial selective inversion recovery (IR) pulse. STUDY TYPE: Retrospective. POPULATION: A total of 85 patients with physiologically normal pancreatobiliary flow without ductal dilatation (normal group) and 19 patients with dilated pancreatic duct. FIELD STRENGTH/SEQUENCE: A 3 T, fast spin echo sequence with IR pulse to nullify the signal of static pancreatic juice and bile. ASSESSMENT: The frequency and secretion grade of the antegrade and reverse flow of the pancreatic juice and bile on cine-dynamic MRCP were visually evaluated. Additionally, the reciprocal relationship between pancreatic juice and bile flow was evaluated based on its flow patterns. STATISTICAL TESTS: Spearman's rank correlation coefficient analysis and the Kruskal-Wallis and Mann-Whitney U tests were used. P values of <0.05 were considered to indicate statistical significance. RESULTS: In the normal group, the antegrade pancreatic juice flow and no bile flow pattern was most frequently observed (29%), followed by the no pancreatic juice flow and no bile flow pattern (23%), the antegrade pancreatic juice flow and antegrade bile flow pattern (22%), and the no pancreatic juice flow and reverse bile flow pattern (9%). The flow of the pancreatic juice and bile were synchronized with each other in 47%, while they were not in 53%. In the dilated pancreatic duct group, the mean secretion grade of the antegrade bile and pancreatic juice flow was significantly lower than in the normal group. DATA CONCLUSION: Cine-dynamic MRCP with a spatially selective IR pulse can visualize the variations of the physiological flow patterns of bile and pancreatic juice including 53% of unsynchronized patterns. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 5.

Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas With Tilted Excitation Plane: A Preliminary Study.

BACKGROUND: Reduced field-of-view diffusion-weighted imaging (rDWI) with tilted two-dimensional radiofrequency (RF) excitation planes has not yet been applied to the imaging of the pancreas although the utility of this technique which allows the acquisition of high-quality images without aliasing artifacts in the phase-encoding direction has been evaluated for brain and spinal cord imaging. PURPOSE: To evaluate the visual image quality of the pancreas by tilting the excitation plane (tilted rDWI) in comparison to conventional DWI (cDWI) and rDWI without using the tilted excitation plane. STUDY TYPE: Retrospective. POPULATION: Thirty-two patients evaluated for suspected pancreatobiliary diseases. FIELD STRENGTH/SEQUENCE: Echo-planar imaging DWI (cDWI, rDWI, and tilted rDWI) acquired at 3 T. ASSESSMENT: Images from each DWI sequence were analyzed by five radiologists to compare image quality (conspicuity of pancreatic edges, interslice signal homogeneity, overall image quality, and conspicuity of focal pancreatic lesions) and artifacts (presence of blurring or ghosting artifacts, susceptibility artifacts, and aliasing artifact). STATISTICAL TESTS: Shapiro-Wilk test was performed to assess whether data were normally distributed. Friedman test followed by Bonferroni-adjusted Wilcoxon signed-rank test for post hoc analysis was performed to compare image quality and artifact scores. RESULTS: The mean scores for conspicuity of pancreatic edges (3.36 vs. 2.37), interslice signal homogeneity (3.14 vs. 2.81), presence of ghosting artifacts (3.32 vs. 2.66), susceptibility artifacts (3.06 vs. 2.30), and aliasing artifacts (3.90 vs. 2.34), and overall image quality (3.49 vs. 2.36) were significantly higher in the tilted rDWI than in the rDWI (P < 0.017 for all parameters). The conspicuity score for focal pancreatic lesions tended to be higher in tilted rDWI than in rDWI (2.44 vs. 2.00, P = 0.07). DATA CONCLUSION: Tilted rDWI had better image quality and reduced artifacts relative to cDWI and rDWI techniques in the pancreas. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Influence of fat deposition on T1 mapping of the pancreas: evaluation by dual-flip-angle MR imaging with and without fat suppression.

PURPOSE: To evaluate the influence of fat deposition on T1 relaxation time of pancreatic parenchyma using dual-flip-angle T1 mapping with and without fat suppression. METHODS: Forty-five patients who underwent abdominal MR imaging including T1 mapping with dual-flip-angle method on 3T MRI were included. We measured T1 relaxation time of pancreatic parenchyma on the T1 map images with and without fat suppression. T1 relaxation time of bone marrow was also measured as a reference organ with abundant fat deposition. Fat signal fraction (FSF) was also measured at the same location as T1 map images. Then, the correlation between T1 relaxation time and FSF was assessed. RESULTS: T1 relaxation times of pancreatic parenchyma and bone marrow on the T1 map images without fat suppression showed significantly negative correlation with FSF (pancreas, r = - 0.394, P = 0.007; bone marrow, r = - 0.550, P < 0.001), while there were no significant correlations between them on the T1 map images with fat suppression. On the T1 map images without fat suppression, T1 relaxation times of pancreatic parenchyma as well as bone marrow in patients with FSF ≥ 10% were significantly shorter than those in patients with FSF < 10% (pancreas, P = 0.041; bone marrow, P = 0.005). Conversely, on the T1 map images with fat suppression, no significant differences in T1 relaxation times were found between two groups. CONCLUSION: T1 relaxation time of the pancreas on T1 mapping was influenced by the presence of fat deposition. Therefore, fat suppression technique in T1 mapping will be essential for evaluating T1 relaxation time of pancreatic parenchyma.

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.

Associations of coronary plaque characteristics by integrated backscatter intravascular ultrasound with detectability of vessel external elastic lamina using optical frequency domain imaging in human coronary arteries: A sub-analysis of the MISTIC-1 trial.

OBJECTIVES: We sought to examine associations between plaque characteristics by intravascular ultrasound (IVUS) and detectability of external elastic lamina (EEL) by optical frequency domain imaging (OFDI) in human coronary arteries. BACKGROUND: It is often challenging to detect EEL which represents vessel size by light-based imaging modalities due to light intensity attenuation through atherosclerotic plaque. METHODS: IVUS and OFDI prior to stent implantation were sequentially investigated per protocol. We identified corresponding cross-sections by minimum lumen area (MLA) or just distally to side branches as anatomical landmarks. Plaque characterization was determined by integrated backscatter IVUS analysis. We categorized detectable EEL arc by OFDI into four groups: 0≤ and <1 quadrant (group 1), 1≤ and <2 quadrants (group 2), 2≤ and <3 quadrants (group 3), or 3≤ and <4 quadrants (group 4). RESULTS: We prospectively studied 103 vessels in 93 patients with stable coronary artery disease. Corresponding 711 cross-sections were analyzed. Cross-sections with detectable EEL arc <2 quadrants (group 1 or 2) were observed in 86.1% of MLA sites but only in 29.3% of non-MLA sites (p < .05). Percentage plaque area (%PA) appeared to be the strongest predictor to detect EEL arc <2 quadrants with the cut-off of 60.3% (AUC 0.90; sensitivity 79.8%, specificity 85.5%). Lipid pool and calcification remained statistically significant in predicting detectable EEL arc <2 quadrants after adjustment with %PA. CONCLUSIONS: Presence of large plaque burden, lipid pool, and calcification significantly predicts the detectability of EEL by OFDI assessment. Locations with detectable EEL arc <2 quadrants should thus be avoided for optimal stent landing zone.

[Five Cases of Ten-Year Survival after Surgical Treatment of Pancreatic Cancer in Yamaguchi Prefecture].

A questionnaire survey was conducted regarding the prognosis for pancreatic cancer at 8 major hospitals in Yamaguchi Prefecture. A total of 552 patients with pancreatic cancer who underwent radical surgery between 1997 and 2016 were identified. Five of them survived for more than 10 years. Among the 5 patients, none was treated with neoadjuvant chemotherapy: 4 underwent PD and 1 underwent DP-CAR. Two of them were treated with adjuvant chemotherapy. No complications occurred during their postoperative courses. All of them had no recurrence and survived. Here, we reported the longterm postoperative survival of patients with pancreatic cancer with literature review.

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.

Incremental value of high b value diffusion-weighted magnetic resonance imaging at 3-T for prediction of extracapsular extension in patients with prostate cancer: preliminary experience.

PURPOSE: To investigate whether high b value diffusion-weighted imaging (DWI) contributes to the improvement of diagnostic ability of extracapsular extension (ECE) in prostate cancer (PC). MATERIALS AND METHODS: Forty-three patients with PC underwent multiparametric MRI including DWI (b values: 0, 2000 s/mm2) at 3-T. Two radiologists assessed the presence of ECE and the diagnostic certainty degree using conventional diagnostic method by consensus. Tumor apparent diffusion coefficient (ADC, ×10-3 mm2/s) was also measured. Independent predictors of ECE were identified among PSA, tumor ADC, Gleason score, and conventional MRI. ECE in patients with low diagnostic certainty by conventional MRI was further reevaluated using ADC cutoff value, and the results were combined with those of patients with high diagnostic certainty by conventional MRI (MRI + ADC method). RESULTS: Tumor ADC was an independent predictor of ECE, and the ADC cutoff value was 0.72. The sensitivity, specificity, and accuracy of conventional MRI and MRI + ADC method in the diagnosis of ECE were 44, 92, and 72%, and 78, 96, and 88%, respectively. Among MRI findings leading to the judgement of low diagnostic certainty, broad tumor contact was most common (72% of the patients). CONCLUSIONS: The addition of ADC obtained with high b value DWI at 3-T to conventional MRI improved the diagnostic ability of ECE.

Value of preoperative 3T multiparametric MRI for surgical margin status in patients with prostate cancer.

PURPOSE: To examine the value of preoperative multiparametric magnetic resonance imaging (MRI) as a predictor of surgical margin (SM) status in patients with prostate cancer (PC). MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study; the requirement for informed consent was waived. Fifty-six male patients with histologically proven PC underwent preoperative 3T multiparametric MRI including high b value (0, 2000 s/mm(2) ) diffusion-weighted imaging. In each patient, clinical data, such as biopsy Gleason score and D'Amico clinical risk score, and multiparametric MRI findings, such as tumor location, tumor size, tumor extension in the apical or proximal region, tumor apparent diffusion coefficient (ADC), and the presence or absence of MRI findings of extracapsular extension (ECE) were evaluated. Statistical evaluations included the Fisher's exact test, χ(2) test, Mann-Whitney U-test, and logistic regression analysis. RESULTS: On histopathological evaluation, 15 patients (27%) were SM-positive (SMP group), and 41 (73%) were SM-negative (SMN group). The tumor ADC was significantly lower in the SMP group than in the SMN group (P = 0.001). The frequency of tumor extension in the apex or base and suspected ECE on MRI were significantly higher in the SMP group than in the SMN group (P = 0.037 and 0.011, respectively). On multivariate analysis, tumor ADC was the only predictor of SM status in PC (P = 0.003). CONCLUSION: PC with positive SM was characterized by tumor extension in the apical and proximal regions, lower tumor ADC, and tumors with positive MRI findings of ECE, compared to tumors with negative SM. J. Magn. Reson. Imaging 2016;44:584-593.

Pancreatic adenocarcinomas without secondary signs on multiphasic multidetector CT: association with clinical and histopathologic features.

PURPOSE: To determine the clinical, histopathologic and imaging features of pancreatic adenocarcinomas without secondary signs on dynamic CT. MATERIALS AND METHODS: Seventy patients (mean age 70 years) with histologically proven pancreatic adenocarcinoma underwent preoperative contrast material-enhanced multiphasic multidetector CT before pancreatic resection. In each patient, clinical data including carbohydrate antigen 19-9, frequency of isoattenuating tumours, and presence of secondary signs and histopathologic findings such as tumour location, tumour stage, and microscopic infiltrative growth grade were evaluated. RESULTS: Ten tumours (14%) were without secondary signs, and 60 (86%) were with secondary signs. Tumours without and with secondary signs were located in the uncinate process in 5 (50%) and 3 (5%), head in 3 (30%) and 29 (48%), body in 2 (20%) and 22 (37%), and tail in 0 (0%) and 6 (10%), respectively (p = .001). The frequency of isoattenuating pancreatic adenocarcinomas without secondary signs was significantly higher than those with secondary signs (p = 0.034). The tumour stage of pancreatic adenocarcinomas without secondary signs was earlier than that in tumours with secondary signs (p = 0.041). CONCLUSIONS: Pancreatic adenocarcinomas without secondary signs is characterized by the presence of uncinate and isoattenuating tumours and earlier tumour stage compared to tumours with secondary signs. KEY POINTS: Frequency of pancreatic adenocarcinomas without secondary signs on multiphasic CT is 14 . Pancreatic adenocarcinomas without secondary signs are common in the uncinate process. Pancreatic adenocarcinomas without secondary signs are common in isoattenuating tumours. Pancreatic adenocarcinomas without secondary signs are characterized by earlier-stage tumours.

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.

MR dacryocystography: comparison with dacryoendoscopy in positional diagnosis of nasolacrimal duct obstruction.

PURPOSE: To compare the findings of MR dacryocystography with those of dacryoendoscopy and subsequent surgery in patients with nasolacrimal duct obstruction, and to determine the efficacy of MR dacryocystography in the positional diagnosis of nasolacrimal duct obstruction. MATERIALS AND METHODS: Thirty-one patients with clinically suspected nasolacrimal duct obstruction who underwent MR dacryocystography and dacryoendoscopy with subsequent surgical procedure were included. MR dacryocystography was performed by using heavily T2-weighted fast spin echo sequence in the coronal and axial planes after the topical administration of normal saline drops into the conjunctival sacs. RESULTS: In MR dacryocystography, stenosis/obstruction at the canalicular level was correctly diagnosed in nine patients (100 %). Stenosis/obstruction at the lacrimal sac level was correctly diagnosed in 14 of 16 patients (87.5 %) in MR dacryocystography. Three patients with coexistent stenosis/obstruction at both the canalicular and the lacrimal sac level were misinterpreted as stenosis/obstruction at the canalicular level on MR dacryocystography. The overall accuracy of MR dacryocystography in depicting stenosis/obstruction was 84 %. CONCLUSIONS: MR dacryocystography after the topical administration of normal saline drops into the conjunctival sacs is a well-tolerated, minimally invasive imaging technique to identify the level of stenosis/obstruction in patients with nasolacrimal duct obstruction before dacryoendoscopy and subsequent surgery.

Measurement of renal cortical thickness using noncontrast-enhanced steady-state free precession MRI with spatially selective inversion recovery pulse: Association with renal function.

PURPOSE: To assess whether noncontrast-enhanced steady-state free precession (SSFP) magnetic resonance imaging (MRI) with a spatially selective inversion recovery (IR) pulse can improve the visibility of renal corticomedullary differentiation in patients showing renal dysfunction, and to investigate the correlation between renal cortical thickness and estimated glomerular filtration rate (eGFR). MATERIALS AND METHODS: Sixty-five patients with and without chronic kidney diseases (CKD) were investigated. Based on eGFR, patients were divided into three groups (Group 1, eGFR < 60; Group 2, eGFR = 60-90; and Group 3, eGFR > 90). All patients underwent noncontrast-enhanced SSFP MRI with spatially selective IR pulses and minimal renal cortical thickness was measured. RESULTS: The mean corticomedullary contrast ratio was significantly higher in SSFP images with optimal TI than in in-phase images in all three groups (P = 0.001). Positive correlation was seen between the corticomedullary contrast ratio in SSFP images with optimal TI and eGFR (P = 0.011, r = 0.314). A significantly positive correlation was observed between minimal renal cortical thickness and eGFR (P < 0.01, r = 0.495). CONCLUSION: Noncontrast-enhanced SSFP MRI with a spatially selective IR pulse using optimal TI can improve the visibility of renal corticomedullary differentiation even in patients with renal insufficiency. The decrease in renal cortical thickness measured using this technique correlated significantly with eGFR.

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.