Comparative performance of non-contrast MRI with HASTE vs. contrast-enhanced MRI/3D-MRCP for possible choledocholithiasis in hospitalized patients

Traveling gallstones: review of MR imaging and surgical pathology features of gallstone disease and its complications in the gallbladder and beyond

Gallstone-related disease comprises a spectrum of conditions resulting from biliary stone formation, leading to obstruction and inflammatory complications. These can significantly impact patient quality of life and carry high morbidity if not accurately detected. Appropriate imaging is essential for evaluating the extent of gallstone disease and assuring appropriate clinical management. Magnetic Resonance Imaging (MRI) techniques (including Magnetic Resonance Cholangiopancreatography (MRCP) are increasingly used for diagnosis of gallstone disease and its complications and provide high contrast resolution and facilitate tissue-level assessment of gallstone disease processes. In this review we seek to delve deep into the spectrum of MR imaging in diagnose of gallstone-related disease within the gallbladder and complications related to migration of the gallstones to the gall bladder neck or cystic duct, common hepatic duct or bile duct (choledocholithiasis) and beyond, including gallstone pancreatitis, gallstone ileus, Bouveret syndrome, and dropped gallstones, by offering key examples from our practice. Furthermore, we will specifically highlight the crucial role of MRI and MRCP for enhancing diagnostic accuracy and improving patient outcomes in gallstone-related disease and showcase relevant surgical pathology specimens of various gallstone related complications.

Review of strategies to reduce the contamination of the water environment by gadolinium-based contrast agents

Gadolinium-based contrast agents (GBCA) are essential for diagnostic MRI examinations. GBCA are only used in small quantities on a per-patient basis; however, the acquisition of contrast-enhanced MRI examinations worldwide results in the use of many thousands of litres of GBCA per year. Data shows that these GBCA are present in sewage water, surface water, and drinking water in many regions of the world. Therefore, there is growing concern regarding the environmental impact of GBCA because of their ubiquitous presence in the aquatic environment. To address the problem of GBCA in the water system as a whole, collaboration is necessary between all stakeholders, including the producers of GBCA, medical professionals and importantly, the consumers of drinking water, i.e. the patients. This paper aims to make healthcare professionals aware of the opportunity to take the lead in making informed decisions about the use of GBCA and provides an overview of the different options for action.In this paper, we first provide a summary on the metabolism and clinical use of GBCA, then the environmental fate and observations of GBCA, followed by measures to reduce the use of GBCA. The environmental impact of GBCA can be reduced by (1) measures focusing on the application of GBCA by means of weight-based contrast volume reduction, GBCA with higher relaxivity per mmol of Gd, contrast-enhancing sequences, and post-processing; and (2) measures that reduce the waste of GBCA, including the use of bulk packaging and collecting residues of GBCA at the point of application.Critical relevance statement This review aims to make healthcare professionals aware of the environmental impact of GBCA and the opportunity for them to take the lead in making informed decisions about GBCA use and the different options to reduce its environmental burden.Key points• Gadolinium-based contrast agents are found in sources of drinking water and constitute an environmental risk.• Radiologists have a wide spectrum of options to reduce GBCA use without compromising diagnostic quality.• Radiology can become more sustainable by adopting such measures in clinical practice.

A Case of Hemorrhagic Cholecystitis in a Patient on Apixaban After COVID-19 Infection

BACKGROUND Hemorrhagic cholecystitis is a rare cause of abdominal pain, which can result from malignancy, bleeding, or trauma. The presentation, which includes right upper-quadrant pain, nausea, and vomiting, can overlap with other disease states, thereby rendering the diagnosis challenging. CASE REPORT We describe a patient taking apixaban wo had paroxysmal atrial fibrillation with history of joint pain on long-term steroids who developed hemorrhagic cholecystitis following an episode of pneumonia secondary to SARS-CoV-2 virus (COVID-19) infection. The hospital COVID-19 pneumonia protocol included the administration of steroids and symptomatic care. Following discharge, he presented to our hospital with a sudden onset of severe abdominal pain and distention accompanied by elevated liver enzymes and a low hemoglobin level of 78 g/L. Magnetic resonance cholangiopancreatography revealed a distended gallbladder and intraluminal layering, early subacute blood products, and increased wall thickness, which was thought to represent non-calcular hemorrhagic cholecystitis. Furthermore, a stable 18×16×20 mm cyst in the tail of the pancreas was also located posteriorly, with indentation to the splenic vein. The patient was managed conservatively, and the pain subsided on day 3 after admission. CONCLUSIONS Hemorrhagic cholecystitis is rarely reported with the use of the direct oral anticoagulants (DOACs). In our case the combination of a recent COVID-19 hospitalization, steroid use, and possible pancreatic cancer (CA 19-9 288.4 kU/L) may have contributed to such incidence in the setting of apixaban utilization; however, it is not possible to make definitive correlations. Investigating hemorrhagic cholecystitis in the setting of DOAC use in patients with multiple risk factors such as those that existed in our patient is imperative for proper diagnosis and management.

Magnetic resonance cholangiopancreatography: pitfalls in interpretation

Magnetic resonance cholangiopancreatography (MRCP) has become a widely accepted noninvasive diagnostic tool in the assessment of pancreatic and biliary disease. MRCP essentially exploits extended T2 relaxation times of slow-moving fluid and delineates the outline of biliary and pancreatic ducts on T2-weighted images. In order to maximize the clinical implication of MRCP, it is of utmost importance for radiologists to optimize the acquisition technique, be aware of patient-related factors and physiologic changes than can affect its performance and interpretation. It is critical to understand the most common artifacts and pitfalls encountered during acquisition and interpretation of MRCP. We provide a general overview of the different pitfalls encountered in MRCP and pearls on how to manage them in real-world practice.

Influence of Percutaneous Drainage Surgery and the Interval to Perform Laparoscopic Cholecystectomy on Acute Cholecystitis through Genetic Algorithm-Based Contrast-Enhanced Ultrasound Imaging

To discuss the optimal interval time between genetic algorithm-based ultrasound imaging-guided percutaneous drainage surgery (PTGD) and laparoscopic cholecystectomy (LC), 64 cholecystitis patients were selected as the research objects and evenly divided into experimental group (intelligent algorithm was adopted to recognize patients’ ultrasonic images) and control group (professional doctors carried out diagnosis). 92 acute cholecystitis patients undergoing PTGD were divided into three groups. 30 out of the 92 patients received LC within 2 months and were defined as the early group. 32 were performed with LC within 2 to 4 months and were defined as the metaphase group. 28 underwent LC over 4 months and were defined as the late-stage group. The average operation time, the transition from LC to laparotomy, the average postoperative hospital stay, and the incidence of complications of the three groups were compared. The results revealed that the comparison of the diagnostic accuracy and comprehensive effectiveness between experimental group and control group demonstrated that the differences were statistically significant ( $P<0.05$ ). When the optimal interval of implementing LC after PTGD was realized, the corresponding values of the early group were 88.5 minutes, 16.67%, 8.13 days, and 13.75%. Those of the metaphase group were 49.91 minutes, 3.13%, 4.97 days, and 9.52%. Those of the late stage group were 68.78 minutes, 10.71%, 7.09 days, and 11.96%. To sum up, the diagnostic accuracy and comprehensive effectiveness of intelligent algorithm were higher than those of conventional ultrasound, and the optimal interval time of implementing LC after PTGD was 2 to 4 months.

ACCURACY OF ABBREVIATED PROTOCOL OF MAGNETIC RESONANCE CHOLANGIO-PANCREATOGRAPHY IN THE DIAGNOSIS OF CHOLEDOCHOLITHIASIS

BACKGROUND

Abbreviated magnetic resonance imaging protocols have emerged to reduce the examination time of the long protocols eliminating unnecessary pulse sequences to answer a targeted clinical question, without compromising diagnostic information.

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of an abbreviated magnetic resonance cholangiopancreatography (A-MRCP) protocol in patients with suspected choledocholithiasis.

METHODS

This retrospective study evaluated patients (ages 10 + years) that performed consecutive MRCP examination from October 2019 to June 2020, with the clinical suspicion of choledocholithiasis. Readers first evaluated the biliary tree using a four-sequence A-MRCP protocol and later reviewed the entire conventional eleven-sequence MRCP. Presence of choledocholithiasis, stone size, common bile duct caliber, and additional findings were evaluated.

RESULTS

A total of 148 patients with MRCP were included (62.8% female, mean 50.9 years). The prevalence of choledocholithiasis was 32.2%. The accuracy of the abbreviated MRCP protocol for choledocholithiasis was 98.7%. There was no difference between the performance of the abbreviated and conventional MRCP image sets for detection of choledocholithiasis (kappa=0.970), with a sensitivity of 98% and a specificity of 99%. There was excellent inter-reader agreement evaluating for choledocholithiasis on both imaging sets of MRCP protocols (kappa values were 0.970).

CONCLUSION

An abbreviated MRCP protocol to evaluate for choledocholithiasis provides similar diagnostic over the conventional MRCP protocol, offering potential for decreased scanning time and improved patient tolerability.

ACR Appropriateness Criteria® Jaundice

Jaundice is the end result of myriad causes, which makes the role of imaging in this setting particularly challenging. In the United States, the most common causes of all types of jaundice fall into four categories including hepatitis, alcoholic liver disease, blockage of the common bile duct by a gallstone or tumor, and toxic reaction to a drug or medicinal herb. Clinically, differentiating between the various potential etiologies of jaundice requires a detailed history, targeted physical examination, and pertinent laboratory studies, the results of which allow the physician to categorize the type of jaundice into mechanical or nonmechanical causes. Imaging modalities used to evaluate the jaundiced patient (all etiologies) include abdominal ultrasound (US), CT, MR cholangiopancreatography, endoscopic retrograde cholangiopancreatography and endoscopic US. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Improving MR sequence of 18F-FDG PET/MR for diagnosing and staging gastric Cancer: a comparison study to 18F-FDG PET/CT

Purpose

Evaluate the feasibility of fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging in patients with gastric cancer by optimizing the scan protocol and to compare the image quality to ¹⁸F FDG PET and computed tomography (CT).

Methods

The PET/CT and PET/MR imaging were sequentially performed in 30 patients with gastric cancer diagnosed by gastroscope using a single-injection-with-dual-imaging protocol. After intravenous injection of ¹⁸F-FDG (mean, 249 MBq), PET/CT imaging including low-dose CT was performed (mean uptake time, 47 ± 6 min), and PET/MR imaging including a T1-weighted Dixon sequence for attenuation correction and two different T2-weighted sequences was subsequently acquired (88 ± 15 min after ¹⁸F-FDG injection). Four series of images (CT from PET/CT, T1W, T2W Half-Fourier acquisition single-shot turbo spin-echo [T2W-HASTE] and T2W-BLADE from PET/MR) were visually evaluated using a 3–4 points scale for: (1) image artifacts, (2) lesion conspicuity and (3) image fusion quality. The characteristics of the primary lesions were assessed and compared between the PET/CT and PET/MR acquisitions.

Results

The image quality and lesion conspicuity of the T2W-HASTE images were significantly improved compared to that of the T2W-BLADE images. A significantly higher number of artifacts were seen in the T2W-HASTE images compared with the T1W and CT images (p < 0. 05). No differences in the accuracy of image fusion between PET/MR and PET/CT (p > 0. 05); however, significant difference was seen in the lesion conspicuity measurements (p < 0.05) with T2W-HASTE being superior. For information about the primary lesion characteristics, the T2W-HASTE images provided the most successful identifications compared with those of the T1W and PET/CT (13vs7vs5) images.

Conclusions

PET/MR with the T2W-HASTE was better at revealing the details of local stomach lesions compared with PET/CT imaging. Combining the PET/MR with the T2W-HASTE technique is a promising imaging method for diagnosing and staging gastric cancer.

Is MRCP necessary to diagnose pancreas divisum?

Background

The purpose of this study is to compare the performance of three-dimensional magnetic resonance cholangiopancreatography (3D-MRCP) with non-MRCP T2-weighted magnetic resonance imaging (MRI) sequences for diagnosis of pancreas divisum (PD).

Methods

This is a retrospective study of 342 consecutive patients with abdominal MRI including 3D-MRCP. 3D-MRCP was a coronal respiration-navigated T2-weighted sequence with 1.5 mm slice thickness. Non-MRCP T2-weighted sequences were (1) a coronal inversion recovery sequence (TIRM) with 6 mm slice thickness and (2) a transverse single shot turbo spin echo sequence (HASTE) with 4 mm slice thickness. For 3D-MRCP, TIRM, and HASTE, presence of PD and assessment of evaluability were determined in a randomized manner. A consensus read by two radiologists using 3D-MRCP, non-MRCP T2-weighted sequences, and other available imaging sequences served as reference standard for diagnosis of PD. Statistical analysis included performance analysis of 3D-MRCP, TIRM, and HASTE and testing for noninferiority of non-MRCP T2-weighted sequences compared with 3D-MRCP.

Results

Thirty-three of 342 patients (9.7%) were diagnosed with PD using the reference standard. Sensitivity/specificity of 3D-MRCP for detecting PD were 81.2%/69.7% (p < 0.001). Sensitivity/specificity of TIRM and HASTE were 92.5%/93.9 and 98.1%/97.0%, respectively (p < 0.001 each). Grouped sensitivity/specificity of non-MRCP T2-weighted sequences were 99.8%/91.0%. Non-MRCP T2-weighted sequences were non-inferior to 3D-MRCP alone for diagnosis of PD. 20.2, 7.3%, and 2.3% of 3D-MRCP, TIRM, and HASTE, respectively, were not evaluable due to motion artifacts or insufficient duct depiction.

Conclusions

Non-MRCP T2-weighted MRI sequences offer high performance for diagnosis of PD and are noninferior to 3D-MRCP alone.

Trial registration

Not applicable.