The diagnostic MRCP examination: overcoming technical challenges to ensure clinical success

Cholangiopancreatography in cats: a post-mortem comparison of MRI with fluoroscopy, corrosion casting and histopathology

In human medicine, magnetic resonance cholangiopancreatography (MRCP) is a valuable diagnostic tool for hepatobiliary and pancreatic diseases. In veterinary medicine, however, data evaluating the diagnostic value of MRCP are limited. The primary objectives of this prospective, observational, analytical investigation were to assess whether MRCP reliably visualizes the biliary tract and pancreatic ducts in cats without and with related disorders, and whether MRCP images and measurements of the ducts agree with those of fluoroscopic retrograde cholangiopancreatography (FRCP), corrosion casting and histopathology. A secondary objective was to provide MRCP reference diameters for bile ducts, GB, and pancreatic ducts. Donated bodies of 12 euthanized adult cats underwent MRCP, FRCP, and autopsy with corrosion casting of the biliary tract and pancreatic ducts using vinyl polysiloxane. Diameters of the biliary ducts, gallbladder (GB), and pancreatic ducts were measured using MRCP, FRCP, corrosion casts and histopathologic slides. There was an agreement between MRCP and FRCP in measuring diameters of the GB body, GB neck, cystic duct, and common bile duct (CBD) at papilla. Strong positive correlations existed between MRCP and corrosion casting for measuring GB body and neck, cystic duct, and CBD at the extrahepatic ducts' junction. In contrast to the reference methods, post-mortem MRCP did not visualize right and left extrahepatic ducts, and pancreatic ducts in most cats. Based on this study, MRCP with 1.5 Tesla can be regarded as a contributory method to improve the assessment of feline biliary tract and pancreatic ducts when their diameter is >1 mm.

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography in Comparison With Endoscopic Retrograde Cholangiopancreatography for Detection of the Etiology of Obstructive Jaundice

BACKGROUND

Despite technological advances, obstructive jaundice has significant morbidity and mortality rates. When studying obstructive jaundice, endoscopic retrograde cholangiopancreatography (ERCP), the "gold standard" for biliary obstruction identification, might be replaced with magnetic resonance cholangiopancreatography (MRCP), which is a non-invasive procedure.

OBJECTIVE

Diagnostic accuracy of MRCP in comparison with ERCP for the detection of the etiology of obstructive jaundice.

METHODOLOGY

This prospective, observational study included 102 patients who presented with obstructive jaundice as proven by liver function tests. The MRCP was conducted within 24 to 72 hours before the ERCP. A torso phased-array coil (Siemens, Germany) was used for the MRCP. The duodeno-videoscope and general electric fluoroscopy were used to perform the ERCP. The MRCP was evaluated by a classified radiologist who was blinded to the clinical details. An experienced consultant gastroenterologist who was blinded to the results of the MRCP assessed the cholangiogram of each patient. The hepato-pancreaticobiliary system results from both procedures were compared based on the pathology observed, such as choledocholithiasis, pancreaticobiliary strictures, and dilatation of biliary strictures. We determined the sensitivity, specificity, and negative and positive predictive values with 95% confidence intervals. The statistical significance was set at p<0.05.

RESULTS

The most commonly reported pathology was choledocholithiasis, and MRCP diagnosed 55 patients, of which 53 were true positive cases when compared with the ERCP results of the same patients. MRCP demonstrated greater sensitivity and specificity (respectively) for screening choledocholithiasis (96.2, 91.8), cholelithiasis (100, 75.8), pancreatic duct stricture (100, 100), and hepatic duct mass (100, 100) and showed statistically significant values. The sensitivity of MRCP is lower for identifying benign and malignant strictures, but its specificity was observed to be reliable.

CONCLUSION

When it comes to determining the severity of obstructive jaundice, both in its early and later stages, the MRCP technique is widely regarded as a reliable means of diagnostic imaging. The diagnostic function of ERCP has been significantly reduced as a result of the precision of MRCP as well as its non-invasive nature. In addition to being a helpful non-invasive method to identify biliary diseases and avoid unnecessary ERCPs and their risks, MRCP offers good diagnostic accuracy for obstructive jaundice.

Patient- and Examination-Related Predictors of 3D MRCP Image Quality in Children

Background: MRCP provides noninvasive imaging of the biliary tree and pancreatic duct. In our experience, MRCP image quality is commonly suboptimal in children. Objective: To characterize the frequency of nondiagnostic 3D fast spin echo (FSE) MRCP acquisitions and determine predictors of nondiagnostic MRCP image quality in children. Methods: This retrospective study included 200 randomly selected pediatric patients (mean age, 11.7 years; 101 female, 99 male) who underwent MRCP between January 1, 2019 and December 31, 2020. Patient and examination-related variables were recorded. Three fellowship-trained pediatric radiologists independently reviewed 3D FSE MRCP acquisitions for diagnostic quality (diagnostic vs nondiagnostic) and overall image quality score (1-5 scale; 1=worst image quality imaginable, 5=best image quality imaginable). After computing interreader agreement, analyses used readers' most common diagnostic quality assessment and mean image quality score. Multivariable logistic regression and linear regression analyses were used to identify predictor variables of a diagnostic examination and higher image quality score. Results: Interreader agreement for an MRCP acquisition being diagnostic, expressed as kappa, was 0.53-0.71; interreader agreement for image quality score, expressed as intraclass correlation coefficient, was 0.37-0.57. A total of 36/200 (18%) MRCP acquisitions were nondiagnostic; mean image quality score was 3.5 ± 1.1. Multivariable predictors of a diagnostic MRCP acquisition included greater body mass index (OR=1.11 [95% CI: 1.02-1.21], p=.02), scanner field strength of 1.5 T (OR=2.87 [95% CI: 1.23-6.68], p=.01), and presence of acute pancreatitis (OR=4.91 [95% CI: 1.53-15.77], p=.008). Multivariable predictors of a higher image quality score (β=0.05-0.94) included older age (p=.01), imaging under sedation/general anesthesia (p<.001), presence of biliary dilation (p=.004), and inpatient status (p=.02). A lower image quality score was predicted by a scanner field strength of 3 T (β=-0.61, p<.001). A greater amount of time between the start of the MRI examination and the MRCP acquisition exhibited a nonsignificant association with a decrease in image quality score (p=.06). Conclusion: Pediatric MRCP acquisitions are commonly nondiagnostic. Patient-specific and technical factors systematically impact MRCP image quality in children. Clinical Impact: Recognition of image quality predictors that are potentially modifiable and amendable to proactive intervention can guide efforts to optimize MRCP image quality in children.

Quantitative MRCP Imaging: Accuracy, Repeatability, Reproducibility, and Cohort-Derived Normative Ranges

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) is an important tool for noninvasive imaging of biliary disease, however, its assessment is currently subjective, resulting in the need for objective biomarkers.

PURPOSE

To investigate the accuracy, scan/rescan repeatability, and cross-scanner reproducibility of a novel quantitative MRCP tool on phantoms and in vivo. Additionally, to report normative ranges derived from the healthy cohort for duct measurements and tree-level summary metrics.

STUDY TYPE

Prospective.

PHANTOMS/SUBJECTS

Phantoms: two bespoke designs, one with varying tube-width, curvature, and orientation, and one exhibiting a complex structure based on a real biliary tree. Subjects Twenty healthy volunteers, 10 patients with biliary disease, and 10 with nonbiliary liver disease.

SEQUENCE/FIELD STRENGTH

MRCP data were acquired using heavily T2 -weighted 3D multishot fast/turbo spin echo acquisitions at 1.5T and 3T.

ASSESSMENT

Digital instances of the phantoms were synthesized with varying resolution and signal-to-noise ratio. Physical 3D-printed phantoms were scanned across six scanners (two field strengths for each of three manufacturers). Human subjects were imaged on four scanners (two fieldstrengths for each of two manufacturers).

STATISTICAL TESTS

Bland-Altman analysis and repeatability coefficient (RC).

RESULTS

Accuracy of the diameter measurement approximated the scanning resolution, with 95% limits of agreement (LoA) from -1.1 to 1.0 mm. Excellent phantom repeatability was observed, with LoA from -0.4 to 0.4 mm. Good reproducibility was observed across the six scanners for both phantoms, with a range of LoA from -1.1 to 0.5 mm. Inter- and intraobserver agreement was high. Quantitative MRCP detected strictures and dilatations in the phantom with 76.6% and 85.9% sensitivity and 100% specificity in both. Patients and healthy volunteers exhibited significant differences in metrics including common bile duct (CBD) maximum diameter (7.6 mm vs. 5.2 mm P = 0.002), and overall biliary tree volume 12.36 mL vs. 4.61 mL, P = 0.0026).

DATA CONCLUSION

The results indicate that quantitative MRCP provides accurate, repeatable, and reproducible measurements capable of objectively assessing cholangiopathic change. Evidence Level: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:807-820.

A Comparison of MRI Radiographers' Knowledge in Saudi Arabia and the Republic of Ireland in Relation to Image Quality Management, for Abdomen and Pelvic MRI Examinations

PURPOSE

The purpose of this article was to qualitatively compare current MRI radiographers' knowledge from Saudi Arabia and the Republic of Ireland in relation to MR image quality for abdominal and pelvic MRI examinations.

METHODS AND MATERIALS

Semistructured interviews were designed to investigate the professional role of radiographers towards image quality management, personal development in MRI, and training in relation to image quality improvement. Public, private, military, and academic hospitals in the Western region of the Kingdom of Saudi Arabia participated, as did a range of public and private Irish centres. Clinical specialist radiographers (CSRs)/supervisors, and MR radiographers working in MR completed the interviews. These were recorded, coded, and transcribed.

RESULTS

Sixty-one MR radiographers and CSRs/supervisors within 11 MRI departments in the Kingdom of Saudi Arabia and 11 MRI departments in the Republic of Ireland participated in this study. Three themes resulted by using a qualitative data analysis program called NVivo: (1) health care professional and the cultural attitudes with regards to the scope of professional roles, (2) factors affecting image quality, and (3) departmental policy. Participants' knowledge of image quality varied and challenges to achieving optimal quality levels were noted. Differences in clinical practice between countries were identified, as was the impact of clinical experience and levels of education.

CONCLUSION

Differences in attitude and clinical practice between Saudi and Irish radiographers and CSRs/supervisors working in MRI departments were identified. There is a need for further training and subsequent assessment of professional skills, including developing postgraduate opportunities, particularly for Saudi radiographers, to support radiographers in the routine management of MR image quality.

Contrast-Enhanced Magnetic Resonance Cholangiography: Practical Tips and Clinical Indications for Biliary Disease Management

Since its introduction, MRCP has been improved over the years due to the introduction of several technical advances and innovations. It consists of a noninvasive method for biliary tree representation, based on heavily T2-weighted images. Conventionally, its protocol includes two-dimensional single-shot fast spin-echo images, acquired with thin sections or with multiple thick slabs. In recent years, three-dimensional T2-weighted fast-recovery fast spin-echo images have been added to the conventional protocol, increasing the possibility of biliary anatomy demonstration and leading to a significant benefit over conventional 2D imaging. A significant innovation has been reached with the introduction of hepatobiliary contrasts, represented by gadoxetic acid and gadobenate dimeglumine: they are excreted into the bile canaliculi, allowing the opacification of the biliary tree. Recently, 3D interpolated T1-weighted spoiled gradient echo images have been proposed for the evaluation of the biliary tree, obtaining images after hepatobiliary contrast agent administration. Thus, the acquisition of these excretory phases improves the diagnostic capability of conventional MRCP—based on T2 acquisitions. In this paper, technical features of contrast-enhanced magnetic resonance cholangiography are briefly discussed; main diagnostic tips of hepatobiliary phase are showed, emphasizing the benefit of enhanced cholangiography in comparison with conventional MRCP.

Endoscopic management of choledocholithiasis and cholelithiasis in patients with cirrhosis

Treatment of choledocholithiasis and cholelithiasis in patients with cirrhosis often requires diagnostic and therapeutic endoscopy such as endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP). Patients with underlying cirrhosis may have coagulopathy, hepatic encephalopathy, ascites and other comorbidities associated with cirrhosis that can make endoscopic therapy challenging and can be associated with a higher risk of adverse events. Given the unique derangements of physiologic parameters associated with cirrhosis this population requires a truly multifaceted and multidisciplinary understanding between therapeutic endoscopists, hepatologists and anesthesiologists. For therapeutic endoscopists, it is critical to be aware of the specific issues unique to this population of patients to optimize outcomes and avoid adverse events. The epidemiology of gallstone disease, the diagnostic and therapeutic approach to patients with varying degree of hepatic dysfunction, and a review of the available literature in this area are presented.

Analysis of gallstone composition and structure in Jharkhand region

AIM

The aim of this study was to analyze gallstones structurally and chemically as this may help to direct the measures for its treatment.

METHODOLOGY

On the basis of morphology, 459 gallstones were categorized into pigmented, cholesterol, and mixed gallstones and analyzed for their chemical structure and composition. Elementary analysis was done with the help of inductively coupled plasma, optical emission spectrophotometry. Fourier transform infrared spectroscopy was used for compound analysis. The effects of thermal stability were analyzed by thermal gravimetric analysis (TGA). Statistical analysis was done to correlate gallstone composition with their shape and number in gallbladder.

RESULTS

Pigmented gallstones were predominant and generally occurred in multiple forms, cholesterol as solitaire and black pigmented as slug (χ (2) = 3.56; p < 0.001). Scanning electron microscopy showed the crystals of cholesterol in cholesterol gallstones while pigmented gallstones were more compact in structure. Both types of structure were seen in mixed stones while black pigmented stones were amorphous in nature. This difference in structures might be due to difference in chemical compositions. Cholesterol and mixed stones contained basically cholesterol, brown pigmented constituted bilirubin as a major component, and black stones differed from brown pigmented stones by the presence of Ca palmitate. Bilirubin and palmitate were thermally more stable than cholesterol; hence pigmented gallstones were thermally more stable than cholesterol gallstones, as seen in TGA study.

CONCLUSION

Pigmented gallstones were most common in this study of gallstones from the Jharkhand region.