Performance of a new natural oral contrast agent (LumiVision®) in dynamic MR swallowing.

OBJECTIVES: To evaluate image quality by first use of LumiVision® in dynamic MR swallowing, a contrast medium consisting of biological substances versus a gadolinium-buttermilk mixture in patients who underwent Nissen fundoplication due to gastroesophageal reflux disease (GERD). METHODS: The protocol of this retrospective study was approved by the local Institutional Review Board. A hundred twenty-nine patients (146 examinations) underwent a dynamic MR swallowing study (at 1.5 T or 3.0 T) and received an oral contrast agent. Two readers evaluated the distention of the esophagus, contrast, and traceability of the bolus in a 3-point scale. A steady-state coherent sequence (B-FFE, TrueFISP) was used. The patients were divided into 3 different groups: 53 patients received gadolinium chelate (Dotarem®)-buttermilk mixture (GBM) in a dilution of 1:40 as an oral contrast agent; 44 patients received LumiVision® water mixture (LWM) in a dilution of 1:1 and 49 patients received LumiVision® (L) undiluted. RESULTS: GBM showed significantly better results in overall evaluation for both readers in contrast to LWM (p = .003, p = .002). L also reached significantly better results in overall evaluation than LWM in both readers (p = .004, p = .042). There was no significant difference in the overall evaluation between L and GBM (p = .914, p = .376).According to Landis and Koch, interobserver agreement was "substantial" (Cohen's kappa = 0.738) between both readers. CONCLUSION: LumiVision® undiluted showed equal image quality compared to gadolinium-buttermilk mixture. The constellation of LumiVision® water mixture led to a clearly negative result in relation to the image quality compared to LumiVision® undiluted. Therefore, oral ingestion of LumiVision® undiluted is recommended for MR swallowing examinations. KEY POINTS: • LumiVision® undiluted shows significantly better image quality in comparison to LumiVision® diluted in oral application in swallowing MRI. • LumiVision® undiluted shows equal image quality in comparison to gadolinium-buttermilk mixture in oral application. • Oral ingestion of LumiVision® undiluted can replace gadolinium-buttermilk mixture in oral MR examinations.

Swallowing MRI-a reliable method for the evaluation of the postoperative gastroesophageal situs after Nissen fundoplication.

PURPOSE: To evaluate the diagnostic performance of swallowing MRI of the gastroesophageal junction (GEJ) in the postoperative care of patients after laparoscopic antireflux surgery (LARS) MATERIAL AND METHODS: In this institutional review board-approved prospective study, 79 symptomatic patients (mean age, 52.3 years; range, 26-80 years) were evaluated after laparoscopic Nissen fundoplication. MRI findings were correlated with revision surgery, endoscopy, and high-resolution manometry (HRM) as standard of reference. MRI was performed on a 3.0-T unit using T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE) sequences for anatomical assessment of the GEJ followed by dynamic MR swallowing (fast low-angle shot sequences). Four independent readers (two radiologists, two surgeons) rated 83 MR scans according to defined criteria, such as wrap disruption, slipping, recurrent hiatal hernia, and esophageal motility disorder. RESULTS: Wrap disruption was correctly diagnosed concordantly with the standard of reference in 87.8%, slipping in 81.5%, and recurrent hiatal hernia in 84.9% of the cases. For esophageal motility disorder, MRI interpretation was consistent with manometry in 66.2% of the subjects. Interobserver analysis showed substantial agreement for recurrent hiatal hernia (k = 0.703), moderate agreement for wrap disruption (k = 0.585), and fair agreement for motility disorder and slipping (k = 0.234 and k = 0.200, respectively). CONCLUSION: MR swallowing readily depicts the major failure mechanisms of LARS and has good reliability even in non-experienced readers. KEY POINTS: • MR swallowing accurately readily depicts the major failure mechanisms of laparoscopic antireflux surgery and has good reliability even in non-experienced readers. • It should be included in the preoperative workup for revision surgery after fundoplication. • It will be of great benefit to surgeons in considering and planning a reoperation.

TrueFisp versus HASTE sequences in 3T cine MRI: Evaluation of image quality during phonation in patients with velopharyngeal insufficiency.

OBJECTIVE: To evaluate the image quality of two fast dynamic magnetic resonance imaging (MRI) sequences: True fast imaging with steady state precession (TrueFisp) was compared with half-Fourier acquired single turbo-spin-echo (HASTE) sequence for the characterization of velopharyngeal insufficiency (VPI) in repaired cleft palate patients. METHODS: Twenty-two patients (10 female and 12 male; mean age, 17.7 ± 10.6 years; range, 9-31) with suspected VPI underwent 3-T MRI using TrueFisp and HASTE sequences. Imaging was performed in the sagittal plane at rest and during phonation of "ee" and "k" to assess the velum, tongue, posterior pharyngeal wall and a potential VP closure. The results were analysed independently by one radiologist and one orthodontist. RESULTS: HASTE performed better than TrueFisp for all evaluated items, except the tongue evaluation by the orthodontist during phonation of "k" and "ee". A statistically significant difference in favour of HASTE was observed in assessing the velum at rest and during phonation of "k" and "ee", and also in assessing VP closure in both raters (p < 0.05). TrueFisp imaging was twice as fast as HASTE (0.36 vs. 0.75 s/image). CONCLUSION: Dynamic HASTE images were of superior quality to those obtained with TrueFisp, although TrueFisp imaging was twice as fast. KEY POINTS: • Dynamic MRI is an invaluable tool for diagnosing VPI. • Dynamic HASTE images were of superior quality to those obtained with TrueFisp. • TrueFisp imaging was twice as fast as HASTE imaging.

MRI patterns of Nissen fundoplication: normal appearance and mechanisms of failure.

PURPOSE: The purpose of the study was to assess the role of MR fluoroscopy in the evaluation of post-surgical conditions of Nissen fundoplication due to gastro-oesophageal reflux disease (GERD). METHODS: A total of 29 patients (21 patients with recurrent/persistent symptoms and eight asymptomatic patients as the control group) underwent MRI of the oesophagus and gastro-oesophageal junction (GEJ) at 1.5 T. Bolus transit of a buttermilk-spiked gadolinium mixture was evaluated with T2-weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE) and dynamic gradient echo sequences (B-FFE) in three planes. The results of MRI were compared with intraoperative findings, or, if the patients were treated conservatively, with endoscopy, manometry, pH-metry and barium swallow. RESULTS: MRI was able to determine the position of fundoplication wrap in 27/29 cases (93% overall accuracy) and to correctly identify 4/6 malpositions (67%), as well as all four wrap disruptions. All five stenoses in the GEJ were identified and could be confirmed intraoperatively or during dilatation. MRI correctly visualized three cases with motility disorders, which were manometrically confirmed as secondary achalasia. Three patients showed signs of recurrent reflux without anatomical failure. CONCLUSION: MRI is a promising diagnostic method to evaluate morphologic integrity of Nissen fundoplication and functional disorders after surgery. KEY POINTS: MRI offers simultaneous morphological and functional imaging in one diagnostic method. MR fluoroscopy offers the possibility to identify the wrap position. MRI enables a non-invasive diagnosis, providing detailed information for the surgeon.

Is there a role for dynamic swallowing MRI in the assessment of gastroesophageal reflux disease and oesophageal motility disorders?

OBJECTIVES: To evaluate the diagnostic value of dynamic MRI swallowing in patients with symptoms of Gastroesophageal Reflux Disease (GERD). METHODS: Thirty-seven patients (17 m/20f) with typical signs of GERD underwent MR swallowing in the supine position at 1.5 T with a phased-array body coil. Using dynamic, gradient echo sequences (B-FFE) in the coronal, sagittal and axial planes, the bolus passages of buttermilk spiked with gadolinium chelate were tracked. MRI, pH-metry and manometry were performed within 31 days and results were compared. RESULTS: MRI results were concordant with pH-metry in 82% (23/28) of patients diagnosed with abnormal oesophageal acid exposure by pH-metry. Five patients demonstrated typical symptoms of GERD and had positive findings with pH monitoring, but false negative results with MRI. In four of six patients (67%), there was a correct diagnosis of oesophageal motility disorder, according to manometric criteria, on dynamic MRI. The overall accuracy of MRI diagnoses was 79% (27/34). A statistically significant difference was found between the size of hiatal hernia, grade of reflux in MRI, and abnormal acid exposure on pH-monitoring. CONCLUSIONS: MR fluoroscopy may be a promising radiation-free tool in assessing the functionality and morphology of the GE junction. KEY POINTS: • Swallowing MRI can assess anatomy and function of the gastroesophageal-junction • Swallowing MRI can help identifying reflux and motility disorders • Definition of the size of hiatal hernias is possible in all three planes in MR. • Short duration of swallowing MRI enables its application in routine clinical practice.

Pouch volume and pouch migration after Roux-en-Y gastric bypass: a comparison of gastroscopy and 3 D-CT volumetry: is there a "migration crisis"?

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is the second most frequently performed bariatric procedure worldwide. While pouch migration is a common phenomenon after sleeve gastrectomy, it has hardly been documented after RYGB so far. OBJECTIVES: The aim of this study was to correlate the diagnostic performance of gastroscopy of the gastroesophageal junction with 3-dimensional computed tomography (CT) during postoperative care of patients revised due to weight regain after RYGB, with particular attention to intrathoracic pouch migration (ITM) and pouch volume. SETTING: University Hospital Setting, Austria. METHODS: Thirty RYGB patients that were revised owing to weight regain (median age 37.5 yr) before December 2017 were included in this prospective study. CT findings were correlated with gastroscopy regarding pouch size and ITM. Pouch distention was achieved with both oral contrast and effervescent granules. All patients had CT and gastroscopy on the same day. In addition, patients were evaluated for reflux disease based on clinical history. RESULTS: ITM was found in 20 of 30 (66.7%) patients in CT, whereas gastroscopy did not correctly identify any herniation. In 16 of 28 (57.1%) patients pouch measurements at gastroscopy and CT showed a difference <40%. In 2 patients, pouch distention was not sufficient for CT volumetry. The intraclass correlation coefficient proved to be .594. Symptomatic reflux was present in 10 of 30 (33.3%) patients, 5 of whom had ITM. CONCLUSION: ITM is an underreported finding after revised RYGB and missed in gastroscopy. In terms of pouch volume, 3-dimensional-CT volumetry demonstrated only moderate agreement with gastroscopy.

Swallow Magnetic Resonance Imaging Compared to 3D-Computed Tomography for Pouch Assessment and Hiatal Hernias After Roux-en-Y Gastric Bypass.

INTRODUCTION/PURPOSE: Weight regain and weight loss failure after bariatric surgery are important issues that may require a weight regain procedure. Three-dimensional-computed tomography (3D-CT) is a well-established method allowing exact measurements of pouch volume. The aims of this study were to prove the applicability of swallow MRI as a non-ionizing procedure and compare it to 3D-CT in patients after weight regain procedures following RYGB. MATERIALS AND METHODS: Twelve post-RYGB patients who had a follow-up operation for weight regain before 12/2017 were included in this prospective study. Swallow MRI and 3D-CT were performed in each patient to evaluate the size of the anastomosis, pouch volume, and intrathoracic pouch migration (ITM). RESULTS: Mean pouch volume in swallow MRI and 3D-CT were 40.4 ± 21.0 ml and 43.5 ± 30.2 ml, respectively (p = 0.83), and pouch diameter at the maximal distention was 35.3 ± 5.9 ml (MRI) and 31.0 ± 10.0 ml (CT) (p = 0.16). The rate of ITM was 75% in both examinations (p = 1.0). CONCLUSION: Swallow MRI is a valid method for the assessment of pouch volume in different phases of the swallowing process and is comparable to 3D-CT. The diagnosis of ITM using swallow MRI was equal to 3D-CT.

Image quality, lesion detection, and diagnostic efficacy in digital mammography: full-field digital mammography versus computed radiography-based mammography using digital storage phosphor plates.

OBJECTIVE: To compare image quality, the lesion detection, and the diagnostic efficacy of full-field digital mammography (FFDM) and computed radiography-based mammography using digital storage phosphor plates (DSPM) in the evaluation of breast lesions. MATERIALS AND METHODS: In this prospective study, 150 patients with suspicious breast lesions underwent FFDM and DSPM. Nine aspects of image quality (brightness, contrast, sharpness, noise, artifacts, and the detection of anatomic structures, i.e., skin, retromamillary space, glandular tissue, and calcifications) were evaluated by five radiologists. In addition, the detection of breast lesions and the diagnostic efficacy, based on the BI-RADS classification, were evaluated with histologic and follow-up correlation. RESULTS: For contrast, sharpness, and the detection of all anatomic structures, FFDM was rated significantly better (p<0.05). Mass lesions were equally detected, whereas FFDM detected more lesions consisting of calcifications (85 versus 75). DSPM yielded two false-negative results. Both lesions were rated BI-RADS 4 with FFDM, but BI-RADS 2 with DSPM. Both were invasive carcinoma at histology. The sensitivity, specificity, PPV, NPV, and accuracy of FFDM were 1.0, 0.397, 0.636, 1.0, and 0.707, compared to 0.974, 0.397, 0.630, 0.935, and 0.693 of DSPM. CONCLUSION: Based on image quality parameters, FFDM is, in part, significantly better than DSPM. Furthermore, the detection of breast lesions with calcifications is favorable with FFDM. However, the diagnostic efficacy of FFDM and DSPM was equal. The interpretation of the false-negative results suggests that the perception and characterization of breast lesions is not defined solely by the digital mammography system but is strongly influenced by the radiologist, who is one of the determinants in the interpretation of breast imaging.

Pancreatic adenocarcinoma.

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head of the pancreas in 60-70% of cases. By the time of diagnosis, at least 80% of tumors are unresectable. Helical computed tomography (CT) is very effective in detecting and staging adenocarcinoma, with a sensitivity of up to 90% for detection and an accuracy of 80-90% for staging, but it has limitations in detecting small cancers. Moreover, it is not very accurate for determining nonresectability because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. Multidetector-row CT (MDCT) has brought substantial improvements with its inherent ability to visualize vascular involvement in three dimensions. MDCT has been found to be at least equivalent to contrast-enhanced magnetic resonance imaging (MRI) for detecting adenocarcinoma. MRI can be used as a problem-solving tool in equivocal CT: MRI may help rule out pitfalls, such as inflammatory pseudotumor, focal lipomatosis, abscess, or cystic tumors. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps in diagnosing small cancers. Endosonography is, if available, also a very accurate tool for detecting small cancers, with a sensitivity of up to 98%. It is the technique of choice for image-guided biopsy if a histologic diagnosis is required for further therapy.

Lossy three-dimensional JPEG2000 compression of abdominal CT images: assessment of the visually lossless threshold and effect of compression ratio on image quality.

PURPOSE: To retrospectively determine the maximum compression ratio at which compressed images are indistinguishable from the original by using a three-dimensional (3D) wavelet algorithm. MATERIALS AND METHODS: The protocol of this study was approved by the local Institutional Review Board and informed consent was waived. Sixty emergency abdominal computed tomographic (CT) scans of patients (31 men, 29 women; mean age +/- standard deviation, 50.8 years +/- 20.1; range, 17-80 years) with acute abdominal pain were subjected to lossy irreversible three-dimensional Joint Photographic Experts Group 2000 (3D-JPEG2000) compression by using four compression ratios (4:1, 8:1, 12:1, and 16:1). Groups contained five patients for each of 12 common diagnoses for acute abdominal pain. Images were obtained by using a multidetector CT scanner (Sensation Cardiac 64; Siemens, Forcheim, Germany) with 3- and 6-mm-thick sections. Three radiologists independently compared one case-relevant image per patient with the original image at different compression ratios. They had to determine which image was the original by using a forced-choice, two-alternative model and to subjectively rank image quality. For analysis, a binomial test was used, a Bonferroni correction was applied, and a P value of .01 indicated a significant difference. RESULTS: Images compressed at ratios of 4:1 and 8:1 were visually indistinguishable and essentially indistinguishable, respectively, from the original images (P > .01 for all readers). For the 12:1 and 16:1 ratios, all readers definitively (P < .001) identified the original images. CONCLUSION: The highest 3D-JPEG2000 compression ratio for abdominal CT scans, at which compressed images are essentially indistinguishable from the original, is 8:1.