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

The role of MRI in the diagnosis and management of tracheal diverticulum

Background

Multidetector CT is currently the best imaging method for detecting tracheal diverticulum (TD). Compared with CT, MRI is radiation-free and has higher resolution. However, the MRI characteristics of this disease have not been previously reported. The present retrospective study compared the MR and CT imaging features of TD, aiming to examine the role of MRI in TD diagnosis and management.

Methods

Imaging data were collected in 26 TD patients divided into two groups, including the uninfected and infected groups. The MR and CT imaging features (size/wall/channel) of uninfected patients were compared. The performances of MRI and CT in diagnosing and monitoring therapeutic efficacy in infected TD patients were comparatively assessed.

Results

The uninfected group comprised 25 cases with 25 lesions confirmed by CT, including 23 lesions (92%) detected by MRI, with an average diameter of 8.5 mm (range from 3 to 15 mm). Meanwhile, the average diameter was 7.8 mm as measured by CT (range from 2.8 mm to 14.7 mm). The lesion diameters of the two cases not detected by MRI were 2.3 mm and 2 mm. MRI detected walls of all the 23 lesions (23/23), while CT detected no wall (0/23). CT showed channels in 18 lesions (18/23) versus3 for MRI (3/23). The infected case presented with a paratracheal abscess; MRI clearly showed a relationship between the abscess and the trachea, while CT could not show the lesion source. MRI also sensitively showed the whole process of lesion absorption.

Conclusions

MRI can be used as a supplementary method for TD diagnosis, providing information about the wall that cannot be obtained by CT. MRI is superior to CT in diagnosing infected TD cases presenting with a paratracheal abscess, and in monitoring therapeutic efficacy in these patients.

The Role of MRI in Diagnosing and Managing Tracheal Diverticulum

RATIONALE AND OBJECTIVES

Multidetector CT is the best imaging method to diagnose tracheal diverticulum (TD) till now. MRI characteristics of this disease is not reported before. The study report 5 cases of TD, intend to discuss the role of MRI in diagnosing and managing tracheal diverticulum (TD).

MATERIALS AND METHODS

Five cases of TD (include 4 cases of uninfected TD and 1 case of infected TD) with complete CT and MR imaging data were collected and analyzed to compare MR and CT imaging features(location/size/wall/channel) of the disease. The role of MRI in monitoring therapeutic efficacy of infected TD was also discussed.

RESULTS

All cases were located in the right posterolateral region of the trachea at the level between the T1 and T3 vertebrae. MRI was better in showing the wall of TD, and inferior to showing the channel (between TD and the tracheal) than CT. The diameter measured in MR images was longer than measured in CT image. MRI had equal capacity with CT in accurately display the location of the disease. MRI sensitively showed the absorption of infected TD.

CONCLUSION

MRI is helpful in diagnosing TD, especially infected TD. The sign that local thickening and signal increasing of tracheal wall observed on MR images means that a paratracheal abscess may originate from TD. MRI plays an important role in monitoring therapeutic efficacy of infected TD.

Comparisons between image quality and diagnostic performance of 2D- and breath-hold 3D magnetic resonance cholangiopancreatography at 3T

OBJECTIVES

To compare the image quality and diagnostic performance of 2D MRCP to those of breath-hold 3D MRCP using compressed sensing (CS-MRCP) and gradient and spin-echo (GRASE-MRCP) at 3T.

METHODS

From January to November 2018, patients who underwent pancreatobiliary MRI including 2D MRCP and two breath-hold 3D MRCP using CS and GRASE at 3T were included. Three radiologists independently evaluated image quality, motion artifact, and pancreatic cyst conspicuity. Diagnostic performance was assessed for bile duct anatomic variation, bile duct, and pancreatic diseases using a composite algorithm as reference standards. Pancreatic lesion detectability and conspicuity were evaluated using JAFROC and generalized estimating equation analysis.

RESULTS

One hundred patients (male = 50) were included. Bile duct anatomic variation, bile duct and pancreatic diseases were present in respectively 31, 15, and 79 patients. Breath-hold 3D MRCP provided better image quality than 2D MRCP (3.5 ± 0.6 in 2D MRCP; 4.0 ± 0.7 in GRASE-MRCP and 3.9 ± 0.8 in CS-MRCP, p < 0.001 for both). There was no difference in motion artifact between 2D and breath-hold 3D MRCP (p = 0.1). Breath-hold 3D CS-MRCP provided better pancreatic cyst conspicuity than 2D MRCP (2.7 [95% CI: 2.5-3.0] vs. 2.3 [95% CI: 2.1-2.5], p = 0.001). There were no significant differences between the diagnostic performance of the three sequences in the detection of bile duct anatomic variation or pancreatic lesions (p > 0.05).

CONCLUSION

Breath-hold 3D MRCP with GRASE or CS can provide better image quality than 2D MRCP in a comparable scan time.

KEY POINTS

• Breath-hold 3D MRCP using compressed sensing (CS) or gradient and spin-echo (GRASE) provided a better image quality with less image blurring than 2D MRCP. • There were no significant differences between 2D MRCP and breath-hold 3D MRCP in either motion artifact or the number of non-diagnostic exams. • There were no significant differences between 2D MRCP and either type of breath-hold 3D MRCP in the diagnosis of bile duct anatomic variation or detection of pancreatic lesions.

Evaluation of juxtapapillary duodenal diverticula using multiplanar reformation in MDCT: correlation with ERCP findings

OBJECTIVE

To determine the ability of multidetector computed tomography (MPR-MDCT) to identify and classify the juxtapapillary duodenal diverticulum (JPDD), with ERCP findings as the gold standard.

METHODS

We retrospectively reviewed all ERCP examinations (n: 455) performed between January 2010 to December 2018 and selected 105 patients with JPDD as the inclusion criteria. Of those, 28 patients were excluded because of advanced pancreatic carcinoma, incomplete MDCT examinations and biliary catheter insertion. Finally, MDCT examinations of 77 patients with JPDD were assessed for the presence and type of JPDD.

RESULTS

MPR-MDCT was able to identify 71 (92.2%) JPDD in 77 cases with 88.9% accuracy, 83.3% sensitivity, and 91.6% specificity in classifying the type of JPDD. MPR-MDCT performed best in determining type 1 JPDD, with accuracy of 95.4% compared with type 2 (83.3%) and type 3 (87.8%). There was no significant difference between age, gender, incidence of biliary stones and pancreatitis between each type of JPDD. No correlation of sizes with types of JPDD was found.

CONCLUSIONS

MPR-MDCT can accurately identify and classify JPDD. This information will be useful in determining the difficulty of ERCP.

Diagnostic performance of 64-MDCT in detecting ERCP-proven periampullary duodenal diverticula

AIM

To determine the diagnostic performance of 64-slice multidetector computed tomography (64-MDCT) in detecting periampullary duodenal diverticula.

MATERIALS AND METHODS

Medical profiles of 120 endoscopic retrograde cholangiopancreatography (ERCP)-proven patients with (n = 100) and without (n = 20) periampullary duodenal diverticula who had undergone 64-MDCT were retrospectively reviewed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 64-MDCT in detecting periampullary duodenal diverticula were calculated. Potential factors that might influence the diagnostic performance of 64-MDCT in such patients were also examined.

RESULTS

Patients were 60 males and 60 females with the mean age of 68.8 ± 12.7 (27-93) years. Indications of ERCP were common bile duct stricture (n = 62) or stone (n = 41), biliary cholestasis (n = 16) and acute cholangitis (n = 1). The sensitivity, specificity, PPV, and NPV of 64-MDCT in detecting periampullary duodenal diverticula were 76%, 100%, 100%, and 45.5%, respectively. The size of diverticula was the only predictor of 64-MDCT performance, with better results observed in larger (> 20 mm) diverticula.

CONCLUSION

64-MDCT is a highly specific imaging modality in detecting periampullary duodenal diverticula. The diagnostic performance of 64-MDCT increases for larger diverticula.

Balanced MR cholangiopancreatography with motion-sensitised driven-equilibrium (MSDE) preparation: feasibility of Gd-EOB-DTPA-enhanced biliary examination

AIM

To evaluate the effectiveness of motion-sensitised driven-equilibrium (MSDE)-prepared balanced magnetic resonance cholangiopancreatography (MRCP) in a gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA)-enhanced study compared to conventional T2-weighted MRCP.

MATERIALS AND METHODS

Fifteen patients (seven male and eight female patients) prospectively underwent conventional three-dimensional turbo spin-echo T2-weighted MRCP and MSDE-balanced MRCP using a 1.5 T MRI system after hepatobiliary phase image acquisition. For quantitative evaluation, the contrast-to-noise ratio (CNR) of the common hepatic duct to liver tissue was calculated. For qualitative analysis, two radiologists evaluated the depiction of the biliary system and main pancreatic duct (MPD) using a scoring system. Signal suppression of the portal vein (PV) and hepatic vein (HV) on MSDE-balanced MRCP was also scored.

RESULTS

MSDE-balanced MRCP showed significantly higher CNR than T2-weighted MRCP. For all biliary structures, the mean depiction scores of MSDE-balanced MRCP were significantly higher than those of T2-weighted MRCP, whereas the mean depiction score of MPD with MSDE-balanced MRCP was significantly lower than that of T2-weighted MRCP. Signal suppression of the PV and HV was thought to be clinically sufficient.

CONCLUSIONS

MSDE-balanced MRCP more clearly depicted biliary structures compared with T2-weighted MRCP in a Gd-EOB-DTPA-enhanced study. This sequence may be utilised for routine MRCP on Gd-EOB-DTPA-enhanced MRI.

Breath-held MR cholangiopancreatography (MRCP) using a 3D Dixon fat-water separated balanced steady state free precession sequence

A novel 3D breath-held Dixon fat-water separated balanced steady state free precession (b-SSFP) sequence for MR cholangiopancreatography (MRCP) is described and its potential clinical utility assessed in a series of patients. The main motivation is to develop a robust breath-held alternative to the respiratory gated 3D Fast Spin Echo (FSE) sequence, the current clinical sequence of choice for MRCP. Respiratory gated acquisitions are susceptible to motion artifacts and blurring in patients with significant diaphragmatic drift, erratic respiratory rhythms or sleep apnea. A two point Dixon fat-water separation scheme was developed which eliminates signal loss arising from B0 inhomogeneity effects and minimizes artifacts from perturbation of the b-SSFP steady state. Preliminary results from qualitative analysis of 49 patients demonstrate robust performance of the 3D Dixon b-SSFP sequence with diagnostic image quality acquired in a 20-24s breath-hold.