Initial experience with magnetic resonance fluoroscopy in the evaluation of oesophageal motility disorders. Comparison with manometry and barium fluoroscopy

Novel use of dynamic MR hydrography to rule out esophageal perforation post atrial fibrillation ablation in a patient with anaphylaxis to gadolinium

Esophageal thermal injury is one of the most devastating complications of atrial radiofrequency ablation, and its diagnosis can be challenging. In this report, we highlight the novel use of free water as a contrast material to better visualize the esophageal lumen in a patient with anaphylaxis to Iodinated contrast media and Gadolinium who recently underwent atrial fibrillation ablation. This becomes particularly handy in patients with contrast allergy, and further emphasizes the role of multimodality imaging.

MRI-MECH: mechanics-informed MRI to estimate esophageal health

Dynamic magnetic resonance imaging (MRI) is a popular medical imaging technique that generates image sequences of the flow of a contrast material inside tissues and organs. However, its application to imaging bolus movement through the esophagus has only been demonstrated in few feasibility studies and is relatively unexplored. In this work, we present a computational framework called mechanics-informed MRI (MRI-MECH) that enhances that capability, thereby increasing the applicability of dynamic MRI for diagnosing esophageal disorders. Pineapple juice was used as the swallowed contrast material for the dynamic MRI, and the MRI image sequence was used as input to the MRI-MECH. The MRI-MECH modeled the esophagus as a flexible one-dimensional tube, and the elastic tube walls followed a linear tube law. Flow through the esophagus was governed by one-dimensional mass and momentum conservation equations. These equations were solved using a physics-informed neural network. The physics-informed neural network minimized the difference between the measurements from the MRI and model predictions and ensured that the physics of the fluid flow problem was always followed. MRI-MECH calculated the fluid velocity and pressure during esophageal transit and estimated the mechanical health of the esophagus by calculating wall stiffness and active relaxation. Additionally, MRI-MECH predicted missing information about the lower esophageal sphincter during the emptying process, demonstrating its applicability to scenarios with missing data or poor image resolution. In addition to potentially improving clinical decisions based on quantitative estimates of the mechanical health of the esophagus, MRI-MECH can also be adapted for application to other medical imaging modalities to enhance their functionality.

Assessment of esophagogastric junction morphology by dynamic real-time MRI: comparison of imaging features to high-resolution manometry

Purpose

To assess the esophagogastric junction (EGJ) on real-time MRI and compare imaging parameters to EGJ morphology on high-resolution manometry (HRM).

Methods

A total of 105 of 117 eligible patients who underwent real-time MRI and high-resolution manometry for GERD-like symptoms between 2015 and 2018 at a single center were retrospectively evaluated (male n = 57; female n = 48; mean age 52.5 ± 15.4 years). Real-time MRI was performed at a median investigation time of 15 min (1 frame/40 ms). On HRM, EGJ morphology was assessed according to the Chicago classification of esophageal motility disorders. Real-time MRI was performed at 3 T using highly undersampled radial fast low-angle shot acquisitions with NLINV image reconstruction. A 10 mL pineapple juice bolus served as oral contrast agent at supine position. Real-time MRI films of the EGJ were acquired during swallowing events and during Valsalva maneuver. Anatomic and functional MRI parameters were compared to EGJ morphology on HRM.

Results

On HRM, n = 42 patients presented with EGJ type I (40.0%), n = 33 with EGJ type II (31.4%), and n = 30 with EGJ type III (28.6%). On real-time MRI, hiatal hernia was more common in patients with EGJ type III (66.7%) than in patients with EGJ type I (26.2%) and EGJ type II (30.3%; p < 0.001). Sliding hiatal hernia was more frequent in patients with EGJ type II (33.3%) than in patients with EGJ type III (16.7%) and EGJ type I (7.1%; p = 0.017). The mean esophagus–fundus angle of patients was 85 ± 31° at rest and increased to 101 ± 36° during Valsalva maneuver.

Conclusion

Real-time MRI is a non-invasive imaging method for assessment of the esophagogastric junction. Real-time MRI can visualize dynamic changes of the EGJ during swallowing events.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11604-021-01210-9.

New frontiers in esophageal radiology

Esophageal cancer is the sixth most common cause of cancer related mortality worldwide. Advances in treatment have translated into steadily improving survival rates. Accurate preoperative staging of esophageal cancer is imperative in order to provide an accurate prognosis and direct patients to the most appropriate treatment. Current preoperative staging relies on imaging, most commonly endoscopic ultrasound (EUS), computed tomography (CT) and positron emission tomography (PET). A combination of these modalities should be used in preoperative staging, as each has advantages over another. Magnetic resonance imaging (MRI) has always shown promise in its ability to accurately stage esophageal cancer, though it has not been consistently adopted as a common tool for this purpose. Recent research has demonstrated that MRI can become an integral part of esophageal cancer clinical staging. Advances in MR technology that utilize radial sampling allow for shorter, free breathing techniques without degradation of image quality, resulting in improved capability for T and N staging of esophageal cancer. MRI enhanced with superparamagnetic iron oxide (SPIO) and ultrasmall SPIO (USPIO) nanoparticles has been shown to be useful for the detection of metastatic disease in lymph nodes. This article will review the current evidence in the role that imaging plays in staging esophageal cancer.

Assessment of esophageal motility disorders by real-time MRI

PURPOSE

To investigate imaging findings of esophageal motility disorders on dynamic real-time.

MATERIAL AND METHODS

102 patients with GERD-like symptoms were included in this retrospective study between 2015-2018. Dynamic real-time MRI visualized the transit of a 10 mL pineapple juice bolus through the esophagus and EGJ with a temporal resolution of 40 ms. Dynamic and anatomic parameters were measured by consensus reading. Imaging findings were compared to HRM utilizing the Chicago classification of esophageal motility disorders, v3.0.

RESULTS

All 102 patients completed real-time MRI in a median examination time of 15 min. On HRM, 14 patients presented with disorders with EGJ outlet obstruction (EGJOO) (13.7 %), 7 patients with major disorders of peristalsis (6.9 %), and 32 patients with minor disorders of peristalsis (31.4 %). HRM was normal in 49 patients (48.0 %). Incomplete bolus clearance was significantly more frequent in patients with esophageal motility disorders on HRM than in patients with normal HRM (p = 0.0002). In patients with motility disorders with EGJOO and major disorders of peristalsis, the esophageal diameter tended to be wider (23.6 ± 8.0 vs. 21.2 ± 3.5 mm, p = 0.089) and the sphincter length longer (19.7 ± 7.3 vs. 16.7 ± 3.0 mm, p = 0.091) compared to patients with normal HRM. 3/7 patients with achalasia type II were correctly identified by real-time MRI and one further achalasia type II patient was diagnosed with a motility disorder on MRI films. The other 3/7 patients presented no specific imaging features.

CONCLUSION

Real-time MRI is an auxiliary diagnostic tool for the assessment of swallowing events. Imaging parameters may assist in the detection of esophageal motility disorders.

Contribution of magnetic resonance imaging to the management of esophageal diseases: A systematic review

PURPOSE

Currently available imaging modalities used to investigate the esophagus are irradiating or limited to the analysis of the esophageal lumen. Magnetic resonance imaging (MRI) is a non-invasive and non-radiating imaging technique that provides high degrees of soft tissue contrast. Newly developed fast MRI sequences allow for both morphological and functional assessment of the esophageal body and esophagogastric junction. The purpose of this systematic review was to identify the contribution of MRI to the diagnosis and management of esophageal diseases, such as gastroesophageal reflux, esophageal motility disorders, esophageal neoplasms, and portal hypertension.

METHODS

We performed a systematic search of the Medline (via Ovid), EMBASE (via Ovid), PubMed and Cochrane Library databases from inception to December 2018 inclusively, using the MESH major terms "magnetic resonance imaging" AND "esophagus".

RESULTS

The initial search retrieved 310 references, of which 56 were found to be relevant for the study. References were analysed and classified in different subheadings: MRI protocols for the esophagus, gastroesophageal reflux disease, achalasia and other esophageal motility disorders, esophageal cancer, portal hypertension and other esophageal conditions.

CONCLUSION

MR Esophagography might become a non-invasive, non-irradiating technique of choice following diagnostic esophagogastroduodenoscopy for the assessment of esophageal diseases.

Continuous imaging of esophagogastric junction in patients with reflux esophagitis using 320-row area detector CT: a feasibility study

BACKGROUND AND AIM

The function of the lower esophageal sphincter (LES) is evaluated using an esophageal manometric study. However, information regarding the surrounding organs is difficult to obtain with use of a sensor catheter. We investigated the utility of 320-row area detector computed tomography (CT) to evaluate morphological changes of the esophagogastric junction and surrounding organs.

METHODS

The study subjects were 18 healthy volunteers and 29 patients with reflux esophagitis (RE). Immediately after swallowing a diluted contrast agent, continuous imaging of the esophagogastric junctional area was performed for 15 s. Using CT images, the presence or absence of esophageal hiatal hernia, His angle before and after swallowing, size of the diaphragmatic hiatus, morphologically identified-LES (MI-LES) length, intraluminal horizontal area of MI-LES during relaxation phase, MI-LES thickness, abdominal esophagus length, subcutaneous fat area, visceral fat area, and esophagogastric junction fat area were evaluated.

RESULTS

Analysis of CT images showed more frequent occurrence of hiatal hernia, greater His angle, and a larger diaphragmatic hiatus in patients with severe RE, while the lengths of MI-LES and abdominal esophagus were shorter in those patients. Visceral and esophagogastric junction fat areas tended to be greater in patients with RE. In all subjects, the posterior wall of the MI-LES was thicker than the anterior wall.

CONCLUSION

Continuous imaging with 320-row area detector CT is useful to evaluate morphological changes in the esophagogastric junction area in both normal individuals and patients with reflux esophagitis.

Magnetic resonance imaging for simultaneous morphological and functional evaluation of esophageal motility disorders

PURPOSES

The purpose of this study was to evaluate the feasibility and safety of esophageal functional magnetic resonance imaging (fMRI) for the diagnosis of achalasia.

METHODS

Eleven patients with suspected achalasia and three normal subjects underwent fMRI while swallowing clear liquid with original sequences; "T2-weighed single-shot fast spin-echo" and "Fast Imaging Employing Steady-state Acquisition". The fMRI-based diagnosis was compared with that based on manometry. The luminal fluctuation index (LFI) and Dd/Ds ratio were used for the objective evaluation of the esophageal peristalsis and relaxation of the lower esophageal sphincter (LES).

RESULTS

Functional MRI showed a dilated tortuous esophagus with no tumor, poor clearance, simultaneous waves, aperistalsis, and impaired LES relaxation in all but one case, allowing the diagnosis of achalasia with accuracy similar to that of manometry. The LFI (median 0.08, range 0.03-0.25) and Dd/Ds ratio (1.40, 1.0-2.3) of the patient group were significantly lower than those of the normal subjects [1.50, 2.32-4.05, and 2.59 (2.32-4.05)]. No severe adverse events directly related to fMRI were noted.

CONCLUSIONS

Using our protocol, fMRI was considered to be safe and feasible for the diagnosis of achalasia. Given the widespread use of MRI, esophageal fMRI, which does not require exposure to radiation, could be a potentially useful diagnostic tool for patients with esophageal motility disorders.

Functional magnetic resonance in the evaluation of oesophageal motility disorders

Functional magnetic resonance imaging (fMRI) has been recently proposed for the evaluation of the esophagus. Our aim is to assess the role of fMRI as a technique to assess morphological and functional parameters of the esophagus in patients with esophageal motor disorders and in healthy controls. Subsequently, we assessed the diagnostic efficiency of fMRI in comparison to videofluoroscopic and manometric findings in the investigation of patients with esophageal motor disorders. Considering that fMRI was shown to offer valuable information on bolus transit and on the caliber of the esophagus, variations of these two parameters in the different types of esophageal motor alterations have been assessed. fMRI, compared to manometry and videofluoroscopy, showed that a deranged or absent peristalsis is significantly associated with slower transit time and with increased esophageal diameter. Although further studies are needed, fMRI represents a promising noninvasive technique for the integrated functional and morphological evaluation of esophageal motility disorders.

Assessment of gastrointestinal motor functions by MRI: a comprehensive review

BACKGROUND

Magnetic resonance imaging (MRI) is a useful technique for evaluating gastrointestinal (GI) motor functions because it provides multi-planar imaging capability, high imaging speed, good spatial resolution and excellent soft tissue contrast. Moreover, multiple parameters of GI function can be assessed non-invasively during a single study.

PURPOSE

This critical review of the literature discusses the strengths and limitations of MRI for evaluating GI motor functions.

Morpho-functional patterns of physiologic oropharyngeal swallowing evaluated with dynamic fast MRI

With the advent of dynamic fast MRI sequences the act of deglutition can be dynamically visualized in cine-mode. Twenty-three healthy volunteers were enrolled in this study to define the morpho-functional patterns of oral and pharyngeal deglutition using new dynamic MRI techniques. All subjects were previously submitted to video endoscopic assessment, to exclude swallowing abnormalities. As contrast material a combination of yogurt mixed with gadolinium-diethylene diamine pentaacetic acid was used. The protocol was divided into three parts: (a) preliminary assessment of the oral cavity, pharynx and laryngeal structures; (b) morphologic assessment of tongue, soft palate, pharynx, epiglottis and larynx-hyoid bone; (c) dynamic assessment of swallowing without administrating any contrast media and, in subsequent phase, by injecting 5 ml of yogurt-based contrast medium in the patient's mouth. The time resolution was 3-4 images/s. The MR protocol revealed to be effective in the evaluation of normal motility patterns of the structures involved in swallowing. Moreover, the evaluation of the bolus progression, slowdown or stagnation, was possible. On the contrary problems were encountered in calculating precisely the bolus progression time, because of the insufficient temporal resolution. However, more energy should be invested to optimize the spatial and temporal resolution of turbo-FLASH sequences, to obtain a better dynamic representation of a complex function such as deglutition.