Pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography: a preliminary evaluation

Non-medicinal oral contrast in upper abdominal MRI for MR-guided radiotherapy: A scoping review

INTRODUCTION

Using non-medicinal oral contrast agents may aid safe delivery of magnetic resonance image-guided (MR-guided) radiotherapy by improving the ability to visualise and avoid excessive radiation dose to adjacent bowel/stomach. This scoping review aims to map the literature on non-medicinal oral contrasts used in upper-abdominal diagnostic or therapeutic magnetic resonance imaging (MRI) to find potential candidates for employing in MR-guided radiotherapy and identify gaps in knowledge for further study.

METHODS

A scoping review of non-medicinal oral contrast used in upper-abdominal MRI research followed a pre-defined protocol based on Arksey and O'Malley's framework. Data were charted and reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses for Scoping Reviews reporting guidelines.

RESULTS

Forty-seven studies from 1955 screened abstracts were charted. Thirty-one distinct non-medicinal oral contrast were identified, used primarily to enhance tissue visualisation (89 %) or observe motility (11 %) in diagnostic studies. All studies reported to be predominantly quantitative; only 13 % included participant experience via questionnaires and none used qualitative methods. No studies have examined the efficacy of non-medicinal oral contrasts in MR-guided radiotherapy planning or delivery.

CONCLUSION

Non-medicinal oral contrasts have been extensively investigated in diagnostic MRI to enhance gastrointestinal visualisation and assess motility. However, non-medicinal oral contrasts have not been investigated in the context of radiotherapy planning and treatment. Qualitative evaluation of the patient experience of non-medicinal oral contrasts in magnetic resonance image-guided radiotherapy should be considered alongside studies quantifying the potential clinical benefit.

IMPLICATIONS FOR PRACTICE

This review summarises the properties of non-medicinal oral contrasts and identifies critical gaps in the current evidence, particularly the absence of qualitative research in this domain and the unexplored potential for their application in MR-guided radiotherapy planning and delivery.

Imaging cholangiocarcinoma: CT and MRI techniques

Cross-sectional imaging plays a crucial role in the detection, diagnosis, staging, and resectability assessment of intra- and extrahepatic cholangiocarcinoma. Despite this vital function, there is a lack of standardized CT and MRI protocol recommendations for imaging cholangiocarcinoma, with substantial differences in image acquisition across institutions and vendor platforms. In this review, we present standardized strategies for the optimal imaging assessment of cholangiocarcinoma including contrast media considerations, patient preparation recommendations, optimal contrast timing, and representative CT and MRI protocols with individual sequence optimization recommendations. Our recommendations are supported by expert opinion from members of the Society of Abdominal Radiology's Disease-Focused Panel (DFP) on Cholangiocarcinoma, encompassing a broad array of institutions and practice patterns.

Feasibility, classification and potential clinical impact of non-invasive delineation of abdominal lymphatic vessels in patients following TCPC with T2 weighted MRI

Recent research in patients with functionally univentricular hearts (UVH) is focusing on pathologies of the lymphatic vessels. Morphology of the abdominal lymphatic vessels was analyzed by MRI in patients with UVH following total cavopulmonary connection (TCPC) and it was examined, if clinical and laboratory parameters correlate with changes after TCPC. We prospectively examined 33 patients at the age of 19.8 (14.6;30.2) years [median (Q1;Q3)] after TCPC (follow-up 14.3 years (9.7;24.9) with a heavily T2-weighted MRI sequence on a 3.0 T scanner. Examinations in coronal orientation were performed with respiratory gating, slice thickness 0.6 mm, TR 2400 ms, TE 692 ms, FoV 460 mm (covering thoracic and abdominal regions), scan time 14:41 min (13:18;16:30) after a solid meal and a cup of pineapple juice. The findings were classified according to delineation of abdominal lymphatic vessels. Type 1: <3 abdominal vessels (av) definable; type 2: 4-6 av definable; type 3: >6 av and/or oedematous changes or ascites. The results were correlated with parameters obtained at the annual routine check-up. Statistical analysis was performed using U-test and Chi-square test. Fifteen patients (group 1) showed type 3 lymphatic morphologies, two of which had ascites. Eighteen patients (group 2) showed lower grade morphologies (type 1-2). Image quality was rated considering the delineation of the common hepatic duct and did not differ between groups (p = 0.134). "Lymphatic burden" was automatically examined and was indexed to the number of delineated abdominal vessels and showed quantification according to the chosen categories type 1-3. Patients in group 1 were younger at MRI examination (17.4;14.3/18.9 vs. 26.2;18.2/32.3 years, p = 0.03). Superior cavopulmonary connection (SCPC) had been performed earlier in group 1 (9.9;7.9/25.5 vs. 29.2;13.7/66.6 months, p = 0.018). Laboratory examinations in group 1 showed lower levels for Immunoglobulin G (IgG), Lipase, α-Antitrypsin, Cystatin C and TSH. There were no significant differences for total protein, NTproBNP, lymphocytes or platelets. A history of chylothorax was present in 7/15 versus 2/18 p = 0.022. Protein-losing enteropathy (PLE) occurred in 4/15 versus 1/18 (p = 0.092). T2 weighted MRI is feasible for noninvasive delineation of abdominal lymphatic vessel in patients following TCPC. In the long-term follow-up, patients with more pronounced changes of the abdominal lymphatic vessels were younger at SCPC and were more likely to show a history of chylothorax and lower IgG values.

Optimized flow compensation for contrast-enhanced T1-weighted Wave-CAIPI 3D MPRAGE imaging of the brain

Flow-related artifacts have been observed in highly accelerated T1-weighted contrast-enhanced wave-controlled aliasing in parallel imaging (CAIPI) magnetization-prepared rapid gradient-echo (MPRAGE) imaging and can lead to diagnostic uncertainty. We developed an optimized flow-mitigated Wave-CAIPI MPRAGE acquisition protocol to reduce these artifacts through testing in a custom-built flow phantom. In the phantom experiment, maximal flow artifact reduction was achieved with the combination of flow compensation gradients and radial reordered k-space acquisition and was included in the optimized sequence. Clinical evaluation of the optimized MPRAGE sequence was performed in 64 adult patients, who all underwent contrast-enhanced Wave-CAIPI MPRAGE imaging without flow-compensation and with optimized flow-compensation parameters. All images were evaluated for the presence of flow-related artifacts, signal-to-noise ratio (SNR), gray-white matter contrast, enhancing lesion contrast, and image sharpness on a 3-point Likert scale. In the 64 cases, the optimized flow mitigation protocol reduced flow-related artifacts in 89% and 94% of the cases for raters 1 and 2, respectively. SNR, gray-white matter contrast, enhancing lesion contrast, and image sharpness were rated as equivalent for standard and flow-mitigated Wave-CAIPI MPRAGE in all subjects. The optimized flow mitigation protocol successfully reduced the presence of flow-related artifacts in the majority of cases.Relevance statementAs accelerated MRI using novel encoding schemes become increasingly adopted in clinical practice, our work highlights the need to recognize and develop strategies to minimize the presence of unexpected artifacts and reduction in image quality as potential compromises to achieving short scan times.Key points• Flow-mitigation technique led to an 89-94% decrease in flow-related artifacts.• Image quality, signal-to-noise ratio, enhancing lesion conspicuity, and image sharpness were preserved with the flow mitigation technique.• Flow mitigation reduced diagnostic uncertainty in cases where flow-related artifacts mimicked enhancing lesions.

Thoracic lymphatic anomalies in patients with univentricular hearts: correlation of morphologic findings in isotropic T2-weighted MRI with the outcome after fontan palliation

Objectives

In this study we examined the correlation between the extent of thoracic lymphatic anomalies in patients after surgical palliation by total cavopulmonary connection (TCPC) and their outcome in terms of clinical and laboratory parameters.

Materials and methods

We prospectively examined 33 patients after TCPC with an isotropic heavily T2-weighted MRI sequence on a 3.0 T scanner. Examinations were performed after a solid meal, slice thickness of 0.6 mm, TR of 2400 ms, TE of 692 ms, FoV of 460 mm, covering thoracic and abdominal regions. Findings of the lymphatic system were correlated with clinical and laboratory parameters obtained at the annual routine check-up.

Results

Eight patients (group 1) showed type 4 lymphatic abnormalities. Twentyfive patients (group 2) presented less severe anomalies (type 1-3). In the treadmill CPET, group 2 reached step 7.0;6.0/8.0 vs. 6.0;3.5/6.8 in group 1 (p = 0.006*) and a distance of 775;638/854 m vs. 513;315/661 m (p = 0.006*). In the laboratory examinations, group 2 showed significantly lower levels of AST, ALT and stool calprotectin as compared to group 1. There were no significant differences in NT-pro-BNP, total protein, IgG, lymphocytes or platelets, but trends. A history of ascites showed 5/8 patients in group 1 vs. 4/25 patients in group 2 (p = 0.02*), PLE occurred in 4/8 patient in group 1 vs. 1/25 patients in group 2 (p = 0.008*).

Conclusion

In the long-term follow-up after TCPC, patients with severe thoracic and cervical lymphatic abnormalities showed restrictions in exercise capacity, higher liver enzymes and an increased rate of symptoms of imminent Fontan-failure such as ascites and PLE.

Cine gastric MRI reveals altered Gut-Brain Axis in Functional Dyspepsia: gastric motility is linked with brainstem-cortical fMRI connectivity

BACKGROUND

Functional dyspepsia (FD) is a disorder of gut-brain interaction, and its putative pathophysiology involves dysregulation of gastric motility and central processing of gastric afference. The vagus nerve modulates gastric peristalsis and carries afferent sensory information to brainstem nuclei, specifically the nucleus tractus solitarii (NTS). Here, we combine MRI assessment of gastric kinematics with measures of NTS functional connectivity to the brain in patients with FD and healthy controls (HC), in order to elucidate how gut-brain axis communication is associated with FD pathophysiology.

METHODS

Functional dyspepsia and HC subjects experienced serial gastric MRI and brain fMRI following ingestion of a food-based contrast meal. Gastric function indices estimated from 4D cine MRI data were compared between FD and HC groups using repeated measure ANOVA models, controlling for ingested volume. Brain connectivity of the NTS was contrasted between groups and associated with gastric function indices.

KEY RESULTS

Propagation velocity of antral peristalsis was significantly lower in FD compared to HC. The brain network defined by NTS connectivity loaded most strongly onto the Default Mode Network, and more strongly onto the Frontoparietal Network in FD. FD also demonstrated higher NTS connectivity to insula, anterior cingulate and prefrontal cortices, and pre-supplementary motor area. NTS connectivity was linked to propagation velocity in HC, but not FD, whereas peristalsis frequency was linked with NTS connectivity in patients with FD.

CONCLUSIONS & INFERENCES

Our multi-modal MRI approach revealed lower peristaltic propagation velocity linked to altered brainstem-cortical functional connectivity in patients suffering from FD suggesting specific plasticity in gut-brain communication.

MR, T. PP, Jayabalan J. Combined Use of Negative Oral Contrast and Ranitidine for Magnetic Resonance Cholangiopancreatography: A Randomized Controlled Trial

Objective Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive imaging modality to study pancreaticobiliary tree. The primary aim of this study was to compare the image quality of MRCP obtained with the use of ferric ammonium chloride (negative oral contrast) with that of combined use of ferric ammonium chloride and ranitidine (administered orally). Secondary aim was to determine the interobserver agreement between the assessing radiologists.

Materials and Methods The study was a single-center randomized-controlled trial. The patients were randomized into two groups. One group received ranitidine orally and ferric ammonium chloride (Dexorange) and the other group received only the ferric ammonium chloride. The images were qualitatively analyzed independently by the two blinded radiologists. Two scoring systems were used for grading the diagnostic quality of the images: the gastrointestinal tract signal intensity score (range: 1–4) and the structure visibility score (range: 0–3). The mean score of contrast effect and image effect of the two groups were compared by using Mann–Whitney U test. A p-value < 0.05 was considered statistically significant. Interobserver agreement was studied using Cohen kappa coefficient.

Results A total of 93 patients were eligible for the study. Forty-one patients were randomly assigned to the group that received only negative oral contrast and 52 group that received both ranitidine and negative oral contrast. The mean score of the images obtained with using both ranitidine and negative oral contrast was significantly higher when compared with the other group (3.02 vs. 2.7) (p-value = 0.018). However, there was no significant difference in mean structure visualization score of various parts of the pancreaticobiliary system. The interobserver agreement between the two readers in our study was acceptable.

Conclusion Combined use of hematinic syrup and ranitidine increases the image quality by improving the suppression of gastrointestinal fluid signal as compared with the use of only hematinic syrup as negative oral contrast.

Not only manganese, but fruit component effects dictate the efficiency of fruit juice as an oral magnetic resonance imaging contrast agent

Several fruit juices are used as oral contrast agents to improve the quality of images in magnetic resonance cholangiopancreatography. They are often preferred to conventional synthetic contrast agents because of their very low cost, natural origin, intrinsic safety, and comparable image qualities. Pineapple and blueberry juices are the most employed in clinical practice due to their higher content of manganese(II) ions. The interest of pharmaceutical companies in these products is testified by the appearance in the market of fruit juice derivatives with improved contrast efficacy. Here, we investigate the origin of the contrast of blueberry juice, analyze the parameters that can effect it, and elucidate the differences with pineapple juice and manganese(II) solutions. It appears that, although manganese(II) is the paramagnetic ion responsible for the contrast, it is the interaction of manganese(II) with other juice components that modulates the efficiency of the juice as a magnetic resonance contrast agent. On these grounds, we conclude that blueberry juice concentrated to the same manganese concentration of pineapple juice would prove a more efficient contrast agent than pineapple juice.

Main Duct Thresholds for Malignancy Are Different in Intraductal Papillary Mucinous Neoplasms of the Pancreatic Head and Body-Tail

BACKGROUND & AIMS

The risk of malignancy is uncertain for intraductal papillary mucinous neoplasms (IPMNs) with main pancreatic duct (MPD) of 5-9 mm. No study has correlated MPD size and malignancy considering the anatomic site of the gland (head versus body-tail). Our aim was to analyze the significance of MPD in pancreatic head/body-tail as a predictor of malignancy in main-duct/mixed IPMNs.

METHODS

Retrospective analysis of resected patients between 2009-2018 was performed. Malignancy was defined as high-grade dysplasia and invasive carcinoma. MPD diameter was measured with magnetic resonance imaging. Receiver operating characteristic curve (ROC) analysis was utilized to identify optimal MPD cut-off for malignancy. Independent predictors of malignancy were searched.

RESULTS

Malignancy was detected in 74% of 312 identified patients. 213 patients (68.3%) had IPMNs of the pancreatic head and 99 (31.7%) of the body-tail. ROC analysis identified 9 and 7 mm as the optimal MPD cut-offs for malignancy in IPMNs of head and body-tail of the pancreas, respectively. Multivariate analysis confirmed that MPD ≥9 mm (pancreatic head) and ≥7 mm (body-tail) were independent predictors of malignancy along with macroscopic solid components, positive cytology and elevated CA 19-9. The risk of malignancy was low for IPMNs with MPD ≤8 mm (pancreatic head) or ≤6 mm (pancreatic body-tail) unless high-risk stigmata or multiple worrisome features were present.

CONCLUSIONS

Different thresholds of MPD dilation are associated with malignancy in IPMNs of the head and body-tail of the pancreas. The risk of malignancy for IPMNs with MPD ≤8 mm (pancreatic head) or ≤6 mm (pancreatic body-tail) lacking high-risk stigmata or multiple worrisome features is low.

Optimization of pineapple juice amount used as a negative oral contrast agent in magnetic resonance cholangiopancreatography

To evaluate the potential variability of Manganese (Mn2+) in commercial pineapple juice (PJ) produced in different years and to identify the optimal Mn2+ concentration in the correct amount of PJ to be administered prior to Magnetic Resonance Cholangiopancreatography (MRCP) in order to suppress the gastroduodenal (GD) liquid signal. The Mn2+ concentration in PJ produced in different years was defined using Atomic Absorption Spectrometry. The optimal Mn2+ concentration and the amount of PJ, were estimated in an in-vitro analysis, and were then prospectively tested in a population of patients who underwent MRCP. The results were compared with those achieved with the previous standard amount of PJ used in a similar population. The concentrations of Mn2+ in commercial PJ produced in different years did not differ. A total amount of 150 ml (one glass) of PJ having a high Mn2+ content (2.37 mg/dl) was sufficient for the suppression of the GD liquid signal, despite the additional dilution caused by GD liquids since it led to a final concentration of Mn2+ of 0.5-1.00 mg/dl. The optimized single-dose oral administration of 150 ml (approximately one glass) of PJ having a high Mn2+ concentration prior to MRCP was adequate to guarantee the correct amount of Mn2+ to suppress the GD signal.

T2-Weighted High-Resolution Isotropic Magnetic Resonance Lymphangiography of the Thoracic and Abdominal Lymphatic Vessels with and without Previous High-Fat Meal

RATIONALE AND OBJECTIVES

The aim of this study was to assess the potential benefit of a high-fat meal for preparation of patients before lymphangiography of the thoracic and abdominal lymphatic vessels by a heavily T2-weighted 3D magnetic resonance sequence at 3T.

MATERIALS AND METHODS

A heavily T2-weighted 3D Fast-Spin-Echo sequence was applied twice for lymphangiography in 15 healthy volunteers. One examination was performed following overnight fasting and the second examination was conducted 3 hours after a drinking of 200 ml of cream and a solid meal. The effect of a high-fat meal on the visualization of different segments of the thoracic and abdominal lymphatic vessels was analyzed by scoring of the image quality.

RESULTS

Evaluation of the summarized score of all four segments of the thoracic duct showed significantly improved general visualization of the lymphatic system in the postprandial examination when compared to the results obtained after overnight fasting (mean ± SD: 4.5 ± 1.7 vs. 5.9 ± 1.8, p = 0.007*). Regarding different segments of the lymphatic system significant differences between pre and post cream lymphangiographies were found in the cervical segment (p = 0.012*), the inferior thoracic segment (p = 0.003*) and the abdominal segment (p = 0.035*). In contrast, the visualization of the superior thoracic segment was not significantly improved by high fat meal preparation of the subjects (p = 0.388).

CONCLUSION

A high-fat meal 3 hours prior to T2-weighted MR-lymphangiography improves the visualization of the main lymphatic thoracic and abdominal vessels, particularly the abdominal and cervical part as well as the inferior segment of the thoracic duct.

Non-uniform gastric wall kinematics revealed by 4D Cine magnetic resonance imaging in humans

BACKGROUND

Assessment of gastric function in humans has relied on modalities with varying degrees of invasiveness, which are usually limited to the evaluation of single aspects of gastric function, thus requiring patients to undergo a number of often invasive tests for a full clinical understanding. Therefore, the development of a non-invasive tool able to concurrently assess multiple aspects of gastric function is highly desirable for both research and clinical assessments of gastrointestinal (GI) function. Recently, technological advances in magnetic resonance imaging (MRI) have provided new tools for dynamic (or "cine") body imaging. Such approaches can be extended to GI applications.

METHODS

In the present work, we propose a non-invasive assessment of gastric function using a four-dimensional (4D, volumetric cine imaging), free-breathing MRI sequence with gadolinium-free contrast enhancement achieved through a food-based meal. In healthy subjects, we successfully estimated multiple parameters describing gastric emptying, motility, and peristalsis propagation patterns.

KEY RESULTS

Our data demonstrated non-uniform kinematics of the gastric wall during peristaltic contraction, highlighting the importance of using volumetric data to derive motility measures.

CONCLUSIONS & INFERENCES

MRI has the potential of becoming an important clinical and gastric physiology research tool, providing objective parameters for the evaluation of impaired gastric function.

Origin of the MRI Contrast in Natural and Hydrogel Formulation of Pineapple Juice

Magnetic resonance imaging (MRI) often requires contrast agents to improve the visualization in some tissues and organs, including the gastrointestinal tract. In this latter case, instead of intravascular administration, oral agents can be used. Natural oral contrast agents, such as fruit juice, have the advantages of better taste, tolerability, and lower price with respect to the artificial agents. We have characterized the relaxometry profiles of pineapple juice in order to understand the origin of the increase in relaxation rates (and thus of the MRI contrast) in reference to its content of manganese ions. Furthermore, we have characterized the relaxometry profiles of pineapple juice in the presence of alginate in different amounts; the interaction of the manganese ions with alginate slows down their reorientation time to some extent, with a subsequent increase in the relaxation rates. The relaxometry profiles were also compared with those of manganese(II) solutions in 50 mmol/dm³ sodium acetate solution (same pH of pineapple juice), which revealed sizable differences, mostly in the number of water molecules coordinated to the metal ion, their lifetimes, and in the constant of the Fermi-contact interaction. Finally, the fit of the transverse relaxivity shows that the increased viscosity in the hydrogel formulations can improve significantly the negative contrast of pineapple juice at the magnetic fields relevant for clinical MRI.

Diagnostic accuracy of magnetic resonance imaging for the detection of pulmonary nodules simulated in a dedicated porcine chest phantom

OBJECTIVE

CT serves as gold standard for the evaluation of pulmonary nodules. However, CT exposes patients to ionizing radiation, a concern especially in screening scenarios with repeated examinations. Due to recent technological advances, MRI emerges as a potential alternative for lung imaging using 3D steady state free precession and ultra-short echo-time sequences. Therefore, in this study we assessed the performance of three state-of-the-art MRI sequences for the evaluation of pulmonary nodules.

METHODS

Lesions of variable sizes were simulated in porcine lungs placed in a dedicated chest phantom mimicking a human thorax, followed by CT and MRI examinations. Two blinded readers evaluated the acquired MR-images locating and measuring every suspect lesion. Using the CT-images as reference, logistic regression was performed to investigate the sensitivity of the tested MRI-sequences for the detection of pulmonary nodules.

RESULTS

For nodules with a diameter of 6 mm, all three sequences achieved high sensitivity values above 0.91. However, the sensitivity dropped for smaller nodules, yielding an average of 0.83 for lesions with 4 mm in diameter and less than 0.69 for lesions with 2 mm in diameter. The positive predictive values ranged between 0.91 and 0.96, indicating a low amount of false positive findings. Furthermore, the size measurements done on the MR-images were subject to a bias ranging from 0.83 mm to -1.77 mm with standard deviations ranging from 1.40 mm to 2.11 mm. There was no statistically significant difference between the three tested sequences.

CONCLUSION

While showing promising sensitivity values for lesions larger than 4 mm, MRI appears to be not yet suited for lung cancer screening. Nonetheless, the three tested MRI sequences yielded high positive predictive values and accurate size measurements; therefore, MRI could potentially figure as imaging method of the chest in selected follow-up scenarios, e.g. of incidental findings subject to the Fleischner Criteria.

The efficacy of pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography

Background

During magnetic resonance cholangiopancreatography (MRCP), the pancreatobiliary ducts can be obscured by the high-intensity signal from the stomach and duodenum. Pineapple juice may be an alternative to commercially available negative contrast agents, but has not been evaluated locally.

Objectives

To evaluate the efficacy of a local, off-the-shelf pineapple juice preparation as a negative oral contrast agent for MRCP.

Method

An observational, analytical study was conducted during January–December 2017. A 1.5 Tesla MRCP sequence was performed immediately before and after ingestion of 250 mL of a local, commercially-available pineapple juice preparation. Image evaluation was performed by two radiologists with independent, blind assessment of gastric/duodenal signal intensity and biliary /pancreatic duct visibility, before and after pineapple juice.

Results

Fifty adult patients (F = 44, 88%) with median age 44 years (IQR: 34.75, 57) were included. After pineapple juice administration, there was significant measured (1661.51 vs. 1409.94, p < 0.01) and perceived (2.16 vs. 2.72, p < 0.01) duodenal signal reduction but no significant change in measured (1081.17 vs. 1044.38, p = 0.34) or perceived (2.73 vs. 2.84, p = 0.14) gastric signal intensity. Visibility of the common bile duct was significantly improved (3.67 vs. 3.86, p < 0.01), whilst that of the main pancreatic duct showed no significant change (2.92 vs. 2.86, p = 0.44).

Conclusion

The local pineapple juice preparation used in this study is an effective, affordable and natural negative oral contrast agent for enhancement of MRCP images, and specifically improves visualisation of the common bile duct.

Advanced MR Imaging of the Pancreas

MR imaging can be optimized to evaluate a spectrum of pancreatic disorders with advanced sequences aimed to provide quantitative results and increase MR diagnostic capabilities. The pancreas remains a challenging organ to image because of its small size and location deep within the body. Besides its anatomic limitations, pancreatic pathology can be difficult to identify in the early stages. For example, subtle changes in ductal anatomy and parenchymal composition seen in early chronic pancreatitis are imperceptible with other modalities, such as computed tomography. This article reviews the application of MR imaging techniques and emerging MR sequences used in pancreas imaging.

Magnetic resonance cholangiopancreatography at 3T in a single breath-hold: comparative effectiveness between three-dimensional (3D) gradient- and spin-echo and two-dimensional (2D) thick-slab fast spin-echo acquisitions

Background

To compare the depiction conspicuity of three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP) based on gradient- and spin-echo (GRASE) and two-dimensional (2D) thick-slab MRCP using fast spin-echo (FSE) in different segments of hepatic and pancreatic ducts at 3T.

Methods

Both 3D GRASE and 2D thick-slab FSE MRCP, with parameters adjusted under the constraints of specific absorption rate and scan time within single breath-hold, were performed for 95 subjects (M/F =49:46; age range, 25-75) at 3T. Conspicuity of eight ductal segments was graded by two experienced raters using a 4-point score. Situations where one technique is superior or inferior to the other were recorded.

Results

3D GRASE MRCP outperformed 2D thick-slab FSE MRCP in the common bile duct and common hepatic ducts (both with P<0.001), but compared inferiorly in the right hepatic ducts (P<0.001), right posterior hepatic ducts (P<0.005) and pancreatic duct distal (P<0.05). Performing both 3D and 2D MRCP would reduce the number of non-diagnostic readings in the left hepatic duct to 10 remaining (5.3%), compared with 31 (16.3%) or 21 (11.1%) out of 190 readings if using 3D GRASE or 2D thick-slab FSE alone, respectively.

Conclusions

Although 3D GRASE MRCP is preferential to visualize the common bile duct and common hepatic duct within one single breath-hold, the complementary role of 2D thick-slab FSE MRCP in smaller hepatic and pancreatic ducts makes it a useful adjunct if performed additionally.

Rapid 3D navigator-triggered MR cholangiopancreatography with SPACE sequence at 3T: only one-third acquisition time of conventional 3D SPACE navigator-triggered MRCP

PURPOSE

The purpose of this study was to compare the proposed rapid NT-MRCP protocol and the conventional NT-MRCP protocol with respect to image quality as well as the acquisition time.

MATERIALS AND METHODS

Between January 2019 and May 2019, a total number of 67 consecutive patients with suspected pancreaticobiliary diseases were included in this prospective study and underwent 3D rapid MRCP and 3D conventional MRCP sequences. Both acquisition protocols were set from the same navigator-triggered 3D SPACE sequence. The acquisition time was recorded. Two blinded radiologists performed qualitative analyses with respect to overall image quality, motion artifacts, and CBD visibility using a four-point scale. Quantitative evaluation included the contrast, signal-noise ratio (SNR), and contrast-noise ratio (CNR) between the common bile duct (CBD) and periductal tissues. A paired t test was used to assess differences in the qualitative and quantitative evaluations between the two acquisition methods.

RESULTS

All MRCP studies were completed successfully. The mean acquisition time of rapid NT-MRCP (96.64 ± 30.55 s) was significantly lower than that of the conventional NT-MRCP (271.42 ± 61.63 s; p < 0.001).The contrast ratio, SNR, and CNR of the CBD were significantly higher for conventional NT-MRCP than with rapid NT-MRCP images (0.95 ± 0.02 vs. 0.93 ± 0.03, p < 0.001; 10.36 ± 4.63 vs. 8.90 ± 4.71, p = 0.011; 14.01 ± 6.02 vs. 12.22 ± 6.36, p = 0.020, respectively). The rapid MRCP depicted the overall image quality, artifacts, CBD visibility, right and left hepatic duct, segment 2 branch, main pancreatic duct, and cystic duct significantly better compared with conventional MRCP (p < 0.05). There were no statistically significant differences between the two methods regarding visibility of anterior, posterior, and segment 3 branches (p > 0.05).

CONCLUSIONS

In conclusion, the proposed rapid MRCP protocol yielded significantly higher overall image quality and better visualization of the pancreaticobiliary tree with a significantly reduced imaging time without deterioration of image quality compared with the conventional MRCP at 3T.

Advances in Contrast Agents for Contrast-Enhanced Magnetic Resonance Imaging

INTRODUCTION

Magnetic resonance imaging (MRI) is a well-established medical invention in modern medical technology diagnosis. It is a nondestructive, versatile, and sensitive technique with a high spatial resolution for medical diagnosis. However, MRI has some limitations in differentiating certain tissues, particularly tiny blood vessels, pathological to healthy tissues, specific tumors, and inflammatory conditions such as arthritis, atherosclerosis, and multiple sclerosis. The contrast agent (CA) assisted imaging is the best possible solution to resolve the limitations of MRI.

METHOD

The literature review was carried out using the keywords, "MRI, T1&T2 relaxation, MRI CAs, delivery and adverse effects, classification of CAs." The tools used for the literature search were PubMed, Scopus, and Google Scholar.

RESULT AND DISCUSSION

The literature findings focus on MRI technique, limitations, and possible solutions. Primarily, the review focuses on the mechanism of CAs in image formation with detailed explanations of T1 and T2 relaxations, the mechanism of the MRI-CA image formations. This review presents the adverse effects of CA as well as available marketed formulations and recent patents to extent complete information about the MRI-CA.

CONCLUSION

MRI generates detailed visual information of various tissues with high resolution and contrast. The proton present in the biological fluid plays a crucial role in MR image formation, and it is unable to distinguish pathological conditions in many cases. The CAs are the best solution to resolve the limitation by interacting with native protons. The present review discusses the mechanism of CAs in contrast enhancement and its broad classification with the latest literature. Furthermore, the article presents information about CA biodistribution and adverse effects. The review concludes with an appropriate solution for adverse effects and presents the future prospective for researchers to develop advanced formulations.

Signal suppressions of grape syrup and grape syrup/lemon aqueous solutions in magnetic resonance cholangiopancreatography using heavily T2-weighted pulse sequence

Signal suppression of the gastrointestinal tract fluids in magnetic resonance cholangiopancreatography (MRCP) has been performed using various natural and chemical substances with the different MRCP pulse sequences. This study aimed to investigate the signal suppressions of the grape syrup and the grape syrup/lemon aqueous solutions in MRCP using the heavily T2-weighted sequences. For this purpose, the potassium, iron and manganese contents of grape syrup were measured by atomic absorption spectroscopy. The grape syrup and the grape syrup/lemon solutions with the various grape syrup percentages were imaged using the heavily T2-weighted sequences of MRCP such as T2 HASTE thick slab and T2 SPACE. MRCP in the volunteers was performed before and 10 minutes after oral administration of the grape syrup solution. The concentrations of potassium, iron, and manganese in grape syrup were 34.8, 2.4 and 1 mg/l, respectively. The in vitro study showed significantly lower signal to noise ratio using the grape syrup samples comparing to the grape syrup/lemon. The effective signal suppression for the in vitro study and considerable enhancement of negative contrast in the post-contrast MRCP was obtained using a T2 HASTE thick slab sequence. As a conclusion, the grape syrup solution can be used for signal suppression of the gastrointestinal tract fluid in MRCP as an oral negative contrast material. A T2 HASTE thick slab sequence produces suitable contrast in MRCP images using the grape syrup solution.

What is the best fruit juice to use as a negative oral contrast agent in magnetic resonance cholangiopancreatography?

AIM

To identify, in vitro, the best fruit juice to use as oral contrast agent in magnetic resonance cholangiopancreatography (MRCP) and to test, in vivo, the best natural juice and the new parameters in MRCP sequences identified in vitro.

MATERIALS AND METHODS

The in vitro evaluations consisted of measuring the T2 values of a pure solution of manganese (Mn) and iron (Fe) at different concentrations, measuring the content of Mn and Fe in five commercial juices and their T2 relaxation times, and identifying the optimal juice dilution for suppressing the gastrointestinal fluid signal. The new parameters of MRCP sequences were tested in vivo.

RESULTS

Manganese alone strongly influenced the shortening of the T2 values (p=0.004). The T2 value with an echo time (TE) of ≥1,000 ms enabled sufficient intestinal fluid suppression in the case of high juice dilution. A flip angle of 90° maximised the differences between the high signal from static fluids, such as the bile and the fluid in the gastrointestinal tract, using fast imaging employing steady-state acquisition (FIESTA) sequences (p<0.001).

CONCLUSION

The shortening of the T2 relaxation time depended only on the Mn concentration. All the commercial juices had an Mn concentration sufficient to suppress the gastrointestinal fluid signal using long TE sequences. The oral ingestion of commercial juice before MRCP was enough to suppress the signal from the gastrointestinal fluids, regardless of its dilution after ingestion. When using FIESTA sequences, a flip angle of 90° allowed the best suppression of gastrointestinal fluid signals.

Concentrated pineapple juice for visualisation of the oesophagus during magnetic resonance angiography before atrial fibrillation radiofrequency catheter ablation

The purpose of this study was to compare in vitro pineapple juice and a solution of concentrated pineapple juice with a paramagnetic contrast agent in order to determine the feasibility of using the solution of concentrated pineapple juice in vivo for oesophagus visualisation at magnetic resonance angiography (MRA) before the radiofrequency catheter ablation procedure for atrial fibrillation. The pineapple juice was concentrated by a microwave heating evaporation process performed in a domestic microwave oven. Five grams of modified potato starch for every 40 mL of concentrated pineapple juice were added to the concentrated pineapple juice in order to thicken the solution. The solution resulted visually and quantitatively as hyperintense as the contrast agent in vitro (ratio = 1.02). in vivo, no technical difficulties were encountered during the MRA acquisition and a complete enhanced oesophagus was obtained in 37/38 patients (97.4%). The volumetric analysis and the three-dimensional reconstruction were feasible; the quality was rated as diagnostic in every patient. The intensified oesophagus was successfully merged into the electro-anatomical maps in all the patients. In summary, we demonstrated that this technique allows a feasible and safe oesophagus visualisation during MRA.

Repeatability and correlations of dynamic contrast enhanced and T2* MRI in patients with advanced pancreatic ductal adenocarcinoma

BACKGROUND

In current oncological practice of pancreatic ductal adenocarcinoma (PDAC), there is a great demand for response predictors and markers for early treatment evaluation. In this study, we investigated the repeatability and the interaction of dynamic contrast enhanced (DCE) and T2* MRI in patients with advanced PDAC to enable for such evaluation using these techniques.

MATERIALS & METHODS

15 PDAC patients underwent two DCE, T2* and anatomical 3 T MRI sessions before start of treatment. Parametric maps were calculated for the transfer constant (K^trans), rate constant (k_ep), extracellular extravascular space (v_e) and perfusion fraction (v_p). Quantitative R2* (1/T2*) maps were obtained from the multi-echo T2* images. Differences between normal and cancerous pancreas were determined using a Wilcoxon matched pairs test. Repeatability was obtained using Bland-Altman analysis and relations between DCE and T2*/R2* were observed by Spearman correlation and voxel-wise binned plots of tumor voxels.

RESULTS

PDAC K^trans (p = 0.007), k_ep (p < 0.001), v_p (p = 0.035) were lower and v_e (p < 0.001) was higher compared to normal pancreas. The coefficient of variation between sessions was 21.8% for K^trans, 9.9% for k_ep, 19.3% for v_e, 18.2% for v_p and 18.7% for R2*. Variation between patients ranged from 20.2% for k_ep to 43.6% for K^trans. In the tumor both K^trans (r = 0.56, p = 0.030) and v_e (r = 0.54, p = 0.037) showed a positive correlation with T2*. Voxel wise analysis showed a steep increase in R2* for tumor voxels with lower K^trans and v_e.

CONCLUSION

We showed good repeatability of DCE and T2* related MRI parameters in advanced PDAC patients. Furthermore, we have illustrated the relation of DCE K^trans and v_e with tissue T2* and R2* indicating substantial value of these parameters for detecting tumor hypoxia in future studies. The results from our study pave the way for further response evaluation studies and patient selection based on DCE and T2* parameters.

Performance survey on a new standardized formula for oral signal suppression in MRCP

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Recently, a new biological standardized product for MRCP became available.

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The product is considered effective as oral signal suppressor in T2-w images.

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Obtained MRCP imagery show a good image quality.

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Patients’ feedback on taste and palatability is very high.

Background

Orally administered substances, which reduce image contamination by overlying gastrointestinal fluid signals, can be used to enhance the quality of MRCP images. Recently, a new standardized formula consisting of biological substances has become available. The objective of this study is to provide a first assessment of achievable MRCP image quality, taste and palatability of this new dedicated agent.

Methods

In January 2015 to May 2015 practicing radiologists in Germany, Austria and Switzerland were asked to evaluate image quality as well as taste and palatability when using the new agent (LumiVision^®; b.e. imaging; Baden-Baden; Germany) in MRCP questionnaire. Both criteria were rated with a 6-point Likert scale ranging from “1” (best) to “6” (worst).

Results

A total 185 of 475 radiologic institutions (39%) submitted feedback on image quality, 187 (39%) on the taste/palatability. Assessments of image quality regarding presence of disturbing gastrointestinal fluid signal resulted in a median of 2. The majority of patients rated the subjective taste as very good (median of 1). No side effects of relevance were recorded.

Conclusion

This large survey shows that the tested product is considered effective by radiologists regarding MRCP image quality. Patients’ feedback on taste and palatability was very positive.

Efficacy of oral contrast agents for upper gastrointestinal signal suppression in MRCP: A systematic review of the literature

Background

Orally administered substances which suppress signals from gastrointestinal fluid can be used to enhance image quality in magnetic resonance cholangiopancreatography (MRCP). In daily practice, the available substances range from commercial products to regular viands such as fruit juices.

Purpose

To provide an overview on the significance of and the substances used as gastrointestinal fluid signal suppressors in MRCP.

Material and Methods

A systematic review of the existing literature was performed to evaluate the efficacy and efficiency of oral T2-signal suppressors in MRCP.

Results

Twenty-five publications on 16 different oral contrast media were identified. The most commonly used substances were ferumoxsil, ferric ammonium citrate, and pineapple juice. Twenty-three out of 25 publications supported the use of oral signal suppressors in MRCP. Advantages of oral signal suppressors include improved visualization of the pancreatobiliary ductal system, increased help with differential diagnoses, and higher detection rates of relevant diagnoses due to a reduction of overlaying signals.

Conclusion

The application of oral substances for gastrointestinal signal suppression in MRCP is recommendable. A variety of substances are used in daily routine with good but varying effectivity and patient tolerance.

Magnetic resonance cholangiopancreatography (MRCP) using new negative per-oral contrast agent based on superparamagnetic iron oxide nanoparticles for extrahepatic biliary duct visualization in liver cirrhosis

BACKGROUND AND AIMS

Magnetic resonance cholangiopancreatography (MRCP) is often used for imaging of the biliary tree and is required by surgeons before liver transplantation. Advanced liver cirrhosis and ascites in patients however present diagnostic problems for MRCP. The aim of this study was to find out if the use of our negative per-oral contrast agent containing superparamagnetic iron oxide nanoparticles (SPIO) in MRCP is helpful for imaging of hepatobiliary tree in patients with liver cirrhosis.

METHODS

Forty patients with liver cirrhosis were examined on a 1.5 T MR unit using standard MRCP protocol. Twenty patients (group A) underwent MRCP after administration of per-oral SPIO contrast agent 30 min before examination. In group B, twenty patients were examined without per-oral bowel preparation. Ascites was present in eleven patients from group A and in thirteen patients in group B. Four radiologists analyzed MR images for visibility and delineation of the biliary tree. χ² tests were used for comparison of the visibility of intrahepatic and extrahepatic biliary ducts in patients with and without ascites.

RESULTS

Better extrahepatic biliary duct visualization and visibility of extraluminal pathologies in patients with ascites was proved after administration of SPIO contrast agent. No statistically significant difference between group A and B was found for visualization of extrahepatic biliary ducts in patients without ascites. Delineation of intrahepatic biliary ducts was independent on bowel preparation.

CONCLUSIONS

Application of our negative per-oral SPIO contrast agent before MRCP improves the visualization of extrahepatic biliary ducts in patients with ascites which is helpful during the liver surgery, mainly in liver transplantation.

Errors in imaging the pregnant patient with acute abdomen

Pregnant women with an acute abdomen present a critical issue due to the necessity for an immediate diagnosis and treatment; in fact, a diagnostic delay could worsen the outcome for both the mother and the fetus. There is evidence that emergencies during pregnancy are subject to mismanagement; however, the percentage of errors in the diagnosis of emergencies in pregnancy has not been studied in depth. The purpose of this article is to review the most common imaging error emergencies. The topics covered are divided into gynecological and non-gynecological entities and, for each pathology, possible errors have been dealt with in the diagnostic pathway, the possible technical errors in the exam execution, and finally the possible errors in the interpretation of the images. These last two entities are often connected owing to a substandard examination, which can cause errors in the interpretation. Consequently, the systemization of errors reduces the possibility of reoccurrences in the future by providing a valid approach in helping to learn from these errors.

How we do it: MR enterography

Magnetic resonance enterography (MRE) now plays a central role in diagnosing pediatric inflammatory bowel disease (IBD), and its role in other intestinal pathologies such as scleroderma is gradually expanding. MRE helps distinguish between Crohn disease and ulcerative colitis, defining extent and severity. Standard MRE protocols can be optimized in children and adolescents to be diagnostic and well tolerated, both of which are important with increasing use of serial MRE in pediatric IBD for monitoring treatment response and evaluating complications. MRI is especially suited to this role given its lack of ionizing radiation. MRE compliance can be improved through patient education. Differing from adult MRE, pediatric MRE protocols use weight-based formulas to calculate oral and intravenous contrast media and antispasmodic agent doses, using either hyoscine-N-butylbromide or glucagon. Nausea is more commonly experienced with glucagon; however vomiting occurs in <10% of children with either agent. Standard and advanced sequences applied in adults are also used in children and adolescents. These include static and cinematic balanced steady-state free precession sequences, single-shot T2-weighted sequences, diffusion-weighted imaging and pre- and post-contrast 3-D T1-weighted gradient echo sequences. Magnetization transfer imaging and quantitative assessment of bowel to distinguish inflammation and fibrosis are not yet standard in pediatric MRE, but show promise.

[A Low-temperature Manganese Chloride Tetrahydrate Improves the Image Quality of Magnetic Resonance Cholangiopancreatography]

Manganese chloride tetrahydrate (MCT) is one of the oral negative contrast agents which is indispensable for imaging of magnetic resonance cholangiopancreatography (MRCP). In this study, improvement of the image quality of MRCP by using low-temperature MCT is verified. All MR imagings were performed using 1.5 T scanner. The T(1) and T(2) values of the different temperature MCTs were measured in the phantom study. Different concentrations of MCT-doped water (30%, 50%, 70%, and 90%) were measured at several temperature conditions (10°C, 15°C, 23°C, 35°C, and 40°C). As a result, the T(1) and T(2) values became larger with a temperature rise. It was more remarkable in low-concentration MCT. Then, 17 healthy subjects were scanned two times with different temperatures of MCT. The MCT of the normal temperature (23°C) and low temperature (10°C) were taken at consecutive 2 days. The contrast between the stomach and the spleen were significantly higher in 2D half Fourier acquisition single shot turbo spin echo (HASTE) images by use of the low-temperature MCT. The contrast between the common bile duct and the adjacent background were significantly higher in the source images of 3D MRCP by use of the low temperature MCT. In addition, 76% of subjects answered in the questionnaire that the low temperature MCT is easier to drink. The low temperature MCT improves the image quality of MRCP and contributes to performing noninvasive examination.

Evaluation of date syrup as an oral negative contrast agent for MRCP

OBJECTIVE

The purpose of this study was to compare the in vitro effects of date syrup with those of other contrast agents by qualitative and quantitative analysis and in vivo evaluation of the use of date syrup to improve the quality of MRCP images.

MATERIALS AND METHODS

Phantoms containing date syrup, ferumoxsil, pineapple juice, and water were imaged by 1.5-T MRI with T2-weighted and MRCP sequences, and signal-to-noise ratios were calculated. Biochemical analysis of date syrup was performed to find the nature of iron in it, and the iron content was quantified by energy-dispersive x-ray spectroscopy. Sixty patients underwent MRCP before and 30 minutes after ingestion of 100 mL of date syrup. Unenhanced and contrast-enhanced images were scored for gastrointestinal tract signal suppression and visualization of various pancreaticobiliary structures.

RESULTS

In vitro evaluation showed that images obtained with date syrup had a signal-to-noise ratio comparable to that of images obtained with ferumoxsil in T2-weighted and MRCP sequences. The iron concentration in date syrup was 2.6 mg/dL, and it was in ferric form. Images obtained after oral contrast administration had statistically significant improvement in gastrointestinal tract signal suppression (p < 0.001) and an increase in visibility of the common bile duct, cystic duct, and pancreatic duct (all p < 0.001). No adverse effects were noted in any of the patients.

CONCLUSION

Date syrup can be used as a negative oral contrast agent for gastrointestinal tract signal suppression during MRCP and for improving visualization of various pancreaticobiliary structures.

Comparative study of pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography

OBJECTIVES

The aim of this study was to compare the image quality of magnetic resonance Cholangiopancreatography (MRCP) using Pineapple Juice (PJ) or ranitidine as negative oral contrast agents and no agent.

MATERIALS AND METHODS

MRCP images of patients administered PJ (n = 117) or Ranitidine (n = 110) at random, and patients without an agent (n = 50) were evaluated. The subjective image quality of the overall, extra hepatic bile duct and pancreatic duct and the degree of elimination of gastrointestinal fluid were scored by two blinded radiologists. RESULTS were compared using Mann-Whitney's U-test.

RESULTS

The degrees of elimination of gastro duodenal fluid of PJ and ranitidine were significantly better than those without an agent (p < 0.01 and p < 0.01, respectively). The subjective image quality of PJ of the overall and extra hepatic bile duct were significantly better, although no significant differences for ranitidine were observed compared with those without an agent (p < 0.01 and p =0.23, p = 0.025 and p = 0.18). There were no significant differences for the pancreatic duct (p = 0.13 and p = 0.20), nor were there any significant differences in the evaluations between PJ and ranitidine (p = 0.21 and p = 0.96).

CONCLUSION

PJ showed better performance compared to that of conventional ranitidine in terms of pancreatic and biliary depiction and safety.

Interactive neonatal gastrointestinal magnetic resonance imaging using fruit juice as an oral contrast media

BACKGROUND

The objective was to evaluate the use of fruit juice with an interactive inversion recovery (IR) MR pulse sequence to visualise the gastrointestinal tract.

METHODS

We investigated the relaxation properties of 12 different natural fruit juices in vitro, to identify which could be used as oral contrast. We then describe our initial experience using an interactive MR pulse sequence to allow optimal visualisation after administering pineapple juice orally, and suppressing pre-existing bowel fluid contents, with variable TI in three adult and one child volunteer.

RESULTS

Pineapple juice (PJ) had both the shortest T1 (243 ms) and shortest T2 (48 ms) of the fruit juices tested. Optimal signal differentiation between pre-existing bowel contents and oral PJ administration was obtained with TIs of between 900 and 1100 ms.

CONCLUSION

The use of an inversion recovery preparation allowed long T1 pre-existing bowel contents to be suppressed whilst the short T1 of fruit juice acts as a positive contrast medium. Pineapple juice could be used as oral contrast agent for neonatal gastrointestinal magnetic resonance imaging.

The effective use of acai juice, blueberry juice and pineapple juice as negative contrast agents for magnetic resonance cholangiopancreatography in children

Magnetic resonance cholangiopancreatography (MRCP) is commonly performed in the evaluation of known or suspected pancreaticobiliary disease in children. The administration of a negative oral contrast agent can improve the quality of the examination without significant additional cost. We describe our experience with certain brands of acai juice, blueberry juice and pineapple juice as negative oral contrast agents in children. We believe these fruit juices are safe, palatable and may improve MRCP image quality.

On the physiology of normal swallowing as revealed by magnetic resonance imaging in real time

The aim of this study was to assess the physiology of normal swallowing using recent advances in real-time magnetic resonance imaging (MRI). Therefore ten young healthy subjects underwent real-time MRI and flexible endoscopic evaluations of swallowing (FEES) with thickened pineapple juice as oral contrast bolus. MRI movies were recorded in sagittal, coronal, and axial orientations during successive swallows at about 25 frames per second. Intermeasurement variation was analyzed and comparisons between real-time MRI and FEES were performed. Twelve distinct swallowing events could be quantified by real-time MRI (start time, end time, and duration). These included five valve functions: oro-velar opening, velo-pharyngeal closure, glottal closure, epiglottic retroflexion, and esophageal opening; three bolus transports: oro-velar transit, pharyngeal delay, pharyngeal transit; and four additional events: laryngeal ascent, laryngeal descent, vallecular, and piriform sinus filling and pharyngeal constriction. Repetitive measurements confirmed the general reliability of the MRI method with only two significant differences for the start times of the velo-pharyngeal closure (t(8) = −2.4, P ≤ 0.046) and laryngeal ascent (t(8) = −2.6, P ≤ 0.031). The duration of the velo-pharyngeal closure was significantly longer in real-time MRI compared to FEES (t(8) = −3.3, P ≤ 0.011). Real-time MRI emerges as a simple, robust, and reliable tool for obtaining comprehensive functional and anatomical information about the swallowing process.

Whole-body MRI with diffusion-weighted sequence for staging of patients with suspected ovarian cancer: a clinical feasibility study in comparison to CT and FDG-PET/CT

OBJECTIVES

To evaluate whole-body MRI with diffusion-weighted sequence (WB-DWI/MRI) for staging and assessing operability compared with CT and FDG-PET/CT in patients with suspected ovarian cancer.

METHODS

Thirty-two patients underwent 3-T WB-DWI/MRI, (18) F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and CT before diagnostic open laparoscopy (DOL). Imaging findings for tumour characterisation, peritoneal and retroperitoneal staging were correlated with histopathology after DOL and/or open surgery. For distant metastases, FDG-PET/CT or image-guided biopsies were the reference standards. For tumour characterisation and peritoneal staging, WB-DWI/MRI was compared with CT and FDG-PET/CT. Interobserver agreement for WB-DWI/MRI was determined.

RESULTS

WB-DWI/MRI showed 94 % accuracy for primary tumour characterisation compared with 88 % for CT and 94 % for FDG-PET/CT. WB-DWI/MRI showed higher accuracy of 91 % for peritoneal staging compared with CT (75 %) and FDG-PET/CT (71 %). WB-DWI/MRI and FDG-PET/CT showed higher accuracy of 87 % for detecting retroperitoneal lymphadenopathies compared with CT (71 %). WB-DWI/MRI showed excellent correlation with FDG-PET/CT (κ = 1.00) for detecting distant metastases compared with CT (κ = 0.34). Interobserver agreement was moderate to almost perfect (κ = 0.58-0.91).

CONCLUSIONS

WB-DWI/MRI shows high accuracy for characterising primary tumours, peritoneal and distant staging compared with CT and FDG-PET/CT and may be valuable for assessing operability in ovarian cancer patients.

KEY POINTS

• Whole-body MRI with diffusion weighting (WB-DWI/MRI) helps to assess the operability of suspected ovarian cancer. • Interobserver agreement is good for primary tumour characterisation, peritoneal and distant staging. • WB-DWI/MRI improves mesenteric/serosal metastatic spread assessment compared with CT and FDG-PET/CT. • Retroperitoneal/cervical-thoracic nodal staging using qualitative DWI criteria was reasonably accurate. • WB-DWI/MRI and FDG-PET/CT showed the highest diagnostic impact for detecting thoracic metastases.

Magnetic resonance imaging of the postoperative pancreas

Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography provides the comprehensive evaluation of patients following pancreatic surgery regarding parenchymal pancreatic changes, ductal abnormalities, evaluation of anastomoses, and detection of tumor recurrence. Normal and pathologic MRI presentations in patients who underwent pancreatic surgery are reviewed. The MRI/magnetic resonance cholangiopancreatography techniques used in the patients after pancreatic surgery are presented, and a concise review of the current array of pancreatic surgical procedures is provided.

Dynamic real-time magnetic resonance imaging for the analysis of voice physiology

PURPOSE OF REVIEW

For a number of years, it has been possible to use dynamic real-time magnetic resonance imaging (MRI) to analyse the dynamic processes which occur in the human body. In the fields of laryngology and phoniatrics, such dynamic processes are found not only in swallowing, but also in voice and speech production. This article aims to present an overview of how the use of MRI might add to our current understanding of the dynamic processes involved in voice production.

RECENT FINDINGS

It is shown that up to now the analysis of vocal fold oscillations has been limited by MRI's relatively low sampling rate of up to 50 Hz. Nevertheless, more detailed analysis does seem possible with regard to the modulation of the power source and vocal tract.

SUMMARY

Dynamic real-time MRI offers a great opportunity for the analysis of voice production in all stages of the voice production system.

Papel da ranitidina como meio de aprimorar a qualidade do exame de colangiopancreatografia por ressonância magnética

OBJETIVO: Avaliar o impacto da ranitidina por via oral na qualidade do exame de colangiopancreatografia por ressonância magnética (CPRM). MATERIAIS E MÉTODOS: Trinta e dois pacientes realizaram CPRM com aquisições 3D e 2D, com três estratégias de supressão do sinal líquido gastrintestinal: a) apenas em jejum; b) 12 horas após ingerir 300 mg de ranitidina; c) após a ingestão de solução de gadolínio. Três observadores avaliaram os estudos, atentos para o grau de visualização da árvore biliopancreática. Foi medida a concordância interobservador com o teste kappa. A diferença entre técnicas e formas de aquisição foi avaliada pela média da soma dos escores de graduação. RESULTADOS: As três estratégias de supressão do sinal líquido gastrintestinal apresentaram elevada reprodutibilidade. A supressão do sinal líquido gastrintestinal com a ranitidina foi semelhante ao jejum e ambas foram piores do que a solução de gadolínio. As aquisições 3D superaram a 2D apenas na visualização do ducto cístico e da vesícula biliar, sendo inferior ou equivalente nos demais segmentos ductais biliopancreáticos. CONCLUSÃO: O uso da ranitidina não parece justificado para aprimorar a avaliação da árvore biliopancreática em exames de CPRM. A CPRM 2D apenas em jejum permite a visualização ductal com elevada qualidade e reprodutibilidade na maioria dos casos.

Use of pineapple juice with gadopentetate dimeglumine as a negative oral contrast for magnetic resonance cholangiopancreatography: a multicentric study

We evaluated the efficacy of pineapple juice with gadopentetate dimeglumine as a negative oral contrast agent for magnetic resonance cholangiopancreatography (MRCP). Images were obtained before and after the intake of a negative oral contrast agent. Images obtained from six different areas of the biliary tree were analyzed by three different radiologists, who were blind to the exams; scores regarding image quality were given to each area. The statistical analysis showed a significant difference between images before and after the use of the contrast agent (P < 0.001) for the three radiologists (R1-R3). Mean scores given by radiologists before the intake of the contrast agent were 2.49 ± 0.42 (R1), 2.62 ± 0.32 (R2), and 2.22 ± 0.46 (R3). After the intake, mean scores were 3.38 ± 0.62 (R1), 3.48 ± 0.55 (R2), and 2.89 ± 0.69 (R3). The ducts that showed the highest scores were the common bile duct and duct of Wirsung, the distal portion of the common bile duct and the cystic duct. We suggest herein that the contrast agent pineapple juice with gadopentate dimeglumine constitutes an efficient negative oral contrast agent for MRCP, for it efficiently eliminates the signal of the digestive tube in MRCP images.