3D MRCP Research Articles

The Value of Secretin-Enhanced MRCP in Patients With Recurrent Acute Pancreatitis.

The purpose of this study is to assess the additional value of secretin-enhanced MRCP over conventional (non-secretin-enhanced) MRCP in diagnosing disease in patients with recurrent acute pancreatitis. A retrospective review of a radiology database found 72 patients with recurrent acute pancreatitis who had secretin-enhanced MRCP and ERCP correlation within 3 months of each other between January 2007 and December 2011. Of these patients, 54 had no history of pancreatic tumor or surgery and underwent MRI more than 3 months after an episode of acute pancreatitis. In addition, 57 age- and sex-matched control subjects with secretin-enhanced MRCP and ERCP correlation and without a diagnosis of recurrent acute pancreatitis or chronic pancreatitis were enrolled as the control group. All studies were anonymized, and secretin-enhanced MRCP images (image set A) were separated from conventional 2D and 3D MRCP and T2-weighted images (image set B). Image sets A and B for each patient were assigned different and randomized case numbers. Two blinded reviewers independently assessed both image sets for ductal abnormalities and group A image sets for exocrine response to secretin. There were statistically significantly more patients with recurrent acute pancreatitis with reduced exocrine function compared with patients in the control group (32% vs 9%; p < 0.01) on secretin-enhanced images. Patients with recurrent acute pancreatitis were more likely to have side branch dilation (p = 0.02; odds ratio, 3.6), but not divisum, compared with the control group. Secretin-enhanced images were superior to non-secretin-enhanced images for detecting ductal abnormalities in patients with recurrent acute pancreatitis, with higher sensitivity (76% vs 56%; p = 0.01) and AUC values (0.983 vs 0.760; p < 0.01). Up to one-third of patients with recurrent acute pancreatitis showed exocrine functional abnormalities. Secretin-enhanced MRCP had a significantly higher yield for ductal abnormalities than did conventional MRI and should be part of the MRCP protocol for investigation of patients with recurrent acute pancreatitis.

Anatomic variants of the pancreatic duct and their clinical relevance: an MR-guided study in the general population.

To investigate the frequency of pancreatic duct (PD) variants and their effect on pancreatic exocrine function in a population-based study using non-invasive secretin-stimulated magnetic resonance cholangiopancreatography (sMRCP). Nine hundred and ninety-five volunteers, 457 women and 538 men, aged 51.9 ± 13.4 years, underwent navigator-triggered, T2-weighted, 3D turbo spin echo MRCP on a 1.5 T system after 1 unit/kg secretin administration. Two readers evaluated images for PD variants. Pancreatic exocrine function and morphological signs of chronic pancreatitis such as abnormalities of the main PD, side branch dilatation, and pancreatic cysts were evaluated and related to PD variants using a Kruskal-Wallis test and post hoc analysis. Of all sMRCP, 93.2% were of diagnostic quality. Interobserver reliability for detection of PD variants was found to be kappa 0.752 (95 %CI, 0.733 - 0.771). Normal PD variants were observed in 90.4% (n = 838/927). Variants of pancreas divisum was identified in 9.6% (n = 89/927). Abnormalities of the main PD, side branch dilatation, and pancreatic cysts were observed in 2.4%, 16.6%, and 27.7%, respectively, and were not significantly different between pancreas divisum and non-divisum group (P = 0.122; P = 0.152; P = 0.741). There was no association between PD variants and pancreatic exocrine function (P = 0.367). PD variants including pancreas divisum are not associated with morphological signs of chronic pancreatitis or restriction of pancreatic exocrine function. MRCP allows the evaluation of pancreatic duct variants and morphological change. Pancreatic duct variants are not associated with morphological signs of chronic pancreatitis. Pancreas divisum is not accompanied by restriction of pancreatic exocrine function. Pancreatic duct variants including pancreas divisum are limited in their clinical relevance.

The utility of secretin-enhanced MRCP in diagnosing congenital anomalies.

To assess the additional value of secretin-enhanced MRCP (SMRCP) over conventional MRCP in diagnosing divisum. Retrospective HIPAA-compliant and IRB-approved review found 140 patients with SMRCP and ERCP correlation within 6months of each other. All studies were anonymized and the SMRCP images (SMRCP image set) were separated from 2D and 3D MRCP and axial and coronal T2-weighted images (conventional MRI image set). Each image set on each patient was assigned different and randomized case numbers. Two reviewers (R1 and R2) independently reviewed the image sets for divisum vs. no divisum, complete divisum vs. incomplete divisum, and the certainty of diagnosis (1=definitely certain, 2=moderately certain, and 3=unsure). ERCP findings were taken as gold standard. There was no difference in age and gender between the divisum (n=97, with 13 incomplete divisum) and no divisum (n=43) groups. In diagnosing divisum anatomy, the sensitivity was higher for SMRCP compared to conventional MRI for R1 (84.5 vs. 72.2, p=0.02) but not R2 (89.7 vs. 84.4, p=0.25). The specificity was higher in SMRCP image set compared to conventional MRI (R1: 88.1 vs. 76.2, p=0.01; R2: 81.4 vs. 65.1, p<0.001). The mean area under ROC curve was higher for SMRCP image set (R1: 0.86 vs. 0.74, p=0.01; R2: 0.87 vs. 0.74, p=0.01). The certainty of diagnosis was higher in SMRCP image set compared to conventional MRI (p=0.02 for both reviewers). SMRCP was not found to be superior in distinguishing incomplete from complete divisum. The main reasons for erroneous SMRCP diagnosis were the presence of an ansa loop in the main duct and ductal strictures due to chronic pancreatitis. Even though the reviewers had more sequences (axial and coronal) to evaluate in the non-secretin image set, there was some improvement in diagnosing divisum with SMRCP.

Secretin-Stimulated MRCP in Volunteers: Assessment of Safety, Duct Visualization, and Pancreatic Exocrine Function

The objective of our study was to investigate secretin-stimulated MRCP in terms of the safety of secretin, improvement of duct visualization, and assessment of pancreatic exocrine function. Eight hundred sixteen volunteers (370 women and 446 men; mean age, 49.7 ± 13.1 [SD] years) underwent 3D MRCP before and after secretin stimulation (1 U/kg of body weight) at 1.5 T. For the first 2 hours after secretin injection, subjects were evaluated for adverse reactions. Improvement of duct visualization after secretin stimulation was subjectively evaluated by two readers and was quantified by duct diameter measurements. Pancreatic exocrine function was evaluated subjectively by two readers according to the duodenal filling and was quantified using calibrated volumetric measurements of total excreted volume and pancreatic flow output. Two subjects (0.2%) showed flushing (minor adverse reaction). Duct visualization after secretin injection was improved for reader 1 in 468 (57.4%) and for reader 2 in 478 (58.6%) subjects, was unchanged for reader 1 in 324 (39.7%) and for reader 2 in 315 (38.6%) subjects, and was worse for reader 1 in 24 (2.9%) and reader 2 in 23 (2.8%) subjects (interrater agreement, κ = 0.925). Main pancreatic duct diameters increased significantly after secretin stimulation: pancreatic head, 10.5% (mean); body, 12.5%; and tail, 7.7%. Pancreatic exocrine function evaluated according to assessment of duodenal filling was as follows: grade 0 (restricted function) in 0.7% of subjects by both readers, grade 1 (reduced function) in 4.8% of subjects by reader 1 and 4.5% of subjects by reader 2, grade 2 (low-grade reduced function) in 31.1% of subjects by reader 1 and 26.5% of subjects by reader 2, and grade 3 (physiologic function) in 63.4% of subjects by reader 1 and 68.3% of subjects by reader 2 (interrater agreement, κ = 0.838). The mean total excreted volume was 111.8 ± 49.8 (SD) mL, and the mean pancreatic flow output was 9.6 ± 4.2 mL/min. Secretin-stimulated MRCP moderately improves main pancreatic duct visualization and allows noninvasive quantification of pancreatic exocrine function with a negligible risk of side effects.

Correlation between 3D-MRCP and intra-operative findings in right liver donors.

A correct preoperative definition of the hepatic duct confluence anatomy of right liver living donors is a pivotal step in determining their candidacy for donation and planning the surgery. The purposes of this study are to evaluate the accuracy of three-dimensional Magnetic Resonance Cholangiography (3D MRCP) when compared with intraoperative cholangiography (IOC) in assessing biliary anatomy and to identify imaging characteristics that may help predict the yield of hepatic duct orifices in the right liver graft. Twenty consecutive right liver donors were imaged with 3D MRCP and IOC. The MRCP and IOC findings were compared, and the results confirmed against actual donor anatomy. Three-D MRCP accurately predicted the biliary anatomy in 18 of 20 cases. Specificity and positive predictive value of 3D MRCP in defining normal biliary anatomy was 100%. In 2 patients, 3D MRCP failed to indentify abnormal anatomy. The yield of more than one hepatic duct was associated with: (I) The presence of abnormal biliary anatomy, (II) The length of the main right hepatic duct, and (III) The presence of an acute angle at the confluence of right and left hepatic duct. In conclusion, 3D MRCP reliably represents normal biliary anatomy. The presence of anatomical variations decreases MRCP sensitivity and makes IOC or duct probing a necessary tool for accurately performing the transection of the right hepatic duct.

Clinical usefulness of free-breathing navigator-triggered 3D MRCP in non-cooperative patients: Comparison with conventional breath-hold 2D MRCP

To assess the clinical usefulness of free-breathing 3D MRCP in non-cooperative patients compared conventional breath-hold 2D MRCP. We performed FB navigator-triggered 3D MRCP using prospective acquisition correction and BH 2D MRCP in 48 consecutive, non-cooperative patients among 772 patients. Thirteen patients had malignant obstruction. Two radiologists independently graded the likelihood of a malignant obstruction, the overall image quality, and the visibility of ten, individual anatomic segments of both the biliary and pancreatic duct in each sequence. The area under the ROC curve and the repeated measures analyses of variance with multiple comparisons were used for the comparison. The κ statistics were used for interobserver agreement. The diagnostic performance for detecting malignancy was significantly higher on FB MRCP (A(z)=0.962) than on either BH SS-RARE (A(z)=0.820, P<0.0185) or MS-HASTE MRCP (A(z)=0.816, P<0.0067). Interobserver agreement was excellent for FB MRCP (κ=0.889) and fair for both BH SS-RARE (κ=0.578) and MS-HASTE MRCP (κ=0.49). FB MRCP had a significantly higher technical quality than BH MRCP (P<0.001). FB MRCP was seen to have statistically better visibility of peripheral IHD, right main IHD, CHD, cystic duct, and CBD than BH MRCP (P<0.001). FB MRCP and BH SS-RARE MRCP had statistically better visibility of both the left main IHD and pancreatic duct than did BH MS-HASTE MRCP (P<0.001). FB 3D MRCP is useful for non-cooperative patients in whom conventional BH 2D methods cannot be used successfully.

Use of preoperative, 3-dimensional magnetic resonance cholangiopancreatography in pediatric choledochal cysts

Standard choledochal cyst (CC) operations involve dilated extrahepatic bile duct excision followed by biloenterostomy. However, biliary variants and associated intrahepatic bile duct (IHBD) stenoses or dilatations triggering postoperative sequelae require additional procedures. The usefulness of preoperative 3-dimensional magnetic resonance cholangiopancreatography (3D MRCP) and virtual cholangioscopy (VES) for observing biliary morphology and pancreaticobiliary maljunction (PBM) was evaluated. In 16 pediatric CC patients (age range, 4 months to 9 years; median, 3 years), visualization of PBM and aberrant bile duct anatomy and IHBD morphology at the hepatic hilum (HH), umbilical portion (UP), and posterior branch (POST) were compared between 3D-MRCP and intraoperative cholangiography (IOC). VES and intraoperative cholangioscopy (IOS) findings were compared. HH, UP, and POST visualization rates were 100%, 94%, and 94%, respectively, by 3D-MRCP, and 100%, 69%, and 69%, respectively, by IOC. IHBD stenosis detection rates at each region were 38%, 13%, and 13%, respectively, by 3D-MRCP, and 25%, 0%, and 9%, respectively, by IOC. IHBD dilatation detection rates at each part were 75%, 47%, and 60%, respectively, by 3D-MRCP, and 88%, 82%, and 91%, respectively, by IOC. PBM was confirmed in 56% and 93% of cases on 3D-MRCP and IOC, respectively. Both 3D-MRCP and IOC showed biliary variants in 5 cases (31%). VES showed membranous strictures at HH, UP, and POST in 6, 2, and 2 cases, respectively, whereas IOS did so at HH in 4 cases and POST in 2. Preoperative 3D-MRCP and VES accurately depict biliary morphology, allowing concrete operative planning in pediatric CC patients, complementing IOC and IOS.

Defining juxtapapillary diverticulum with 3D segmented trueFISP MRCP: comparison with conventional MRCP sequences with an oral negative contrast agent

To compare three-dimensional segmented true fast imaging with steady-state precession magnetic resonance cholangiopancreatography (3D-trueFISP-MRCP) to conventional MRCP sequences with an oral negative contrast agent for diagnosing juxtapapillary diverticulum. A total of 42 patients with (n = 21) and without (n = 21) juxtapapillary diverticulum confirmed by endoscopic retrograde cholangiopancreatography (ERCP) were evaluated. Three MRCP sequences, 3D-trueFISP-MRCP, two-dimensional rapid acquisition with relaxation enhancement MRCP (2D-RARE-MRCP), and 3D T(2)-weighted turbo spin-echo MRCP (3D-TSE-MRCP), obtained after administering an oral negative contrast agent (FerriSeltz; Otsuka Pharmaceutical, Tokushima, Japan) were compared. Two radiologists independently and blindly interpreted the presence or absence of juxtapapillary diverticulum and its positional relationship against the papilla. The detectability of juxtapapillary diverticulum of each sequence as decided by consensus was then compared. Kappa statistics were used to measure interobserver agreement of the classifications. The sensitivity, specificity, and accuracy for detecting juxtapapillary diverticulum of 3D-trueFISPMRCP (61.9%, 85.7%, and 73.8%) were substantively higher than those of 2D-RARE-MRCP (0.0%, 100%, and 50.0%) and 3D-TSE-MRCP (9.5%, 100%, and 54.8%). Interobserver agreement of the position of juxtapapillary diverticulum by 3D-trueFISP-MRCP was good (kappa = 0.55). 3D-trueFISP-MRCP can define juxtapapillary diverticulum even with an oral negative contrast agent, whereas conventional MRCP sequences cannot.

Biliary anatomy on 3D MRCP: Comparison of volume‐rendering and maximum‐intensity‐projection algorithms

To compare volume-rendering (VR) and maximum-intensity-projection (MIP) of three-dimensional T2-weighted turbo spin-echo magnetic resonance cholangiopancreatography using a free-breathing navigator-triggered prospective acquisition correction (3D-TSE-PACE-MRCP) to define biliary anatomies. VR and MIP images of 3D-TSE-PACE-MRCP for 102 patients were retrospectively evaluated. Interpretation of cystic duct variation and biliary branching patterns of each image were recorded independently by two radiologists in a blinded fashion. Interpretation confidence on a five-point scale was compared using the Wilcoxon signed-rank test. The McNemar test was used to compare the accuracies of each reformation with the reference standard obtained by consensus interpretation of both the images and source images. The reference standard identified all biliary bifurcations and 95 of 102 cystic duct confluences (93.1%). VR findings agreed with the reference standard findings more often than MIP with regard to cystic duct variation (94 [92.2%] vs. 76 [74.5%], P<0.01) while there was no significant difference for biliary branching patterns (99 [97.1%] vs. 92 [90.2%], P=0.092). The mean confidence score was significantly higher with VR than MIP with regard to both cystic duct variation and biliary branching patterns (3.7 vs. 2.4; P<0.01; 4.1 vs. 3.3; P<0.01). VR reformation of 3D-TSE-PACE-MRCP defines biliary anatomies more accurately than MIP.