Magnetic Resonance Sequences Research Articles

Soil microbial communities under wheat and maize straw incorporation are closely associated with soil organic carbon fractions and chemical structure

The incorporation of different types of crop straw may lead to distinct forms and chemical structures of soil organic matter (SOM), which are closely associated with the communities of soil microorganisms in agricultural ecosystems. However, the relationships between the physiochemical composition of SOM and soil microbial communities in response to the incorporation of different types of crop straw remain largely unknown. In this study, we sought to gain insights into these relationships based on a long-term (10 year) field experiment, in which we examined the effects of five treatments [no fertilizer (control), mineral fertilizer (F), mineral fertilizer and wheat straw return (WF), mineral fertilizer and maize straw return (MF), and mineral fertilizer with wheat and maize straw (WMF)]. Using advanced solid-state 13carbon (C) nuclear magnetic resonance and high-throughput sequencing techniques, we investigated the associations between SOM physical fractions and chemical composition and the compositions of soil fungal and bacterial communities Our observations indicated that compared with treatment MF, the long-term incorporation of wheat straw increased the proportions of carbohydrate carbons in light-fraction and coarse-particulate organic matter (cPOM), which were significantly correlated with soil bacterial community composition. Long-term maize straw incorporation was found to increase the proportions of course and fine-POM fractions relative to the WF treatment, as well as the proportions of their aromatic carbons, which were significantly correlated with soil fungal community composition. Collectively, the findings of this study revealed that bacterial and fungal communities are characterized by two distinct responses to wheat and/or maize straw incorporation, which are strongly associated with the physical fractions and chemical structure of SOM, particularly in the case of POM. These findings provide valuable insights for understanding the associations between soil microbial communities and SOM fractions following crop straw incorporation, which will contribute to the development of optimal strategies for crop straw management.

Prenatal diagnosis of fetal ectopia cordis by fetal cardiovascular magnetic resonance imaging.

The purpose of this retrospective study was to report our cases of fetal ectopia cordis (EC) and to evaluate the utility of fetal cardiovascular magnetic resonance imaging (MRI) for the diagnosis of this rare anomaly. This retrospective study included 11 fetuses with EC. The multiplane steady-state free precession (SSFP) sequence, single-shot turbo spin-echo sequence and non-gated SSFP cine cardiovascular magnetic resonance were used to evaluate the fetal heart and abdomen. The 11 fetal cases with EC were examined by fetal cardiovascular MRI and confirmed by postnatal or post-mortem findings. Of these 11 cases, two were isolated thoracic EC, six had pentalogy of Cantrell, and three had an omphalocele and EC. Among all 11 fetuses, nine were associated with congenital heart defects. In four cases, fetal MRI added additional information compared to fetal ultrasound, however, in two cases, fetal MRI missed the diagnosis of a ventricular septal defect noted by echocardiography. Fetal MRI combined with prenatal echocardiography can improve the accuracy of the prenatal diagnosis of EC.

Identification of salmoniformes aquaculture conditions to increase creatine and anserine levels using multiomics dataset and nonnumerical information.

Aquaculture is attracting attention as a sustainable protein source. Salmoniformes, which are generally called salmon, are consumed in large quantities worldwide and are popularly used for aquaculture. In this study, the relationship between muscle metabolites, intestinal microbiota, and nonnumerical information about the ecology of salmoniformes was investigated to improve the efficiency of aquaculture using nuclear magnetic resonance and next-generation sequencing with bioinformatics approach. It was revealed that salmoniformes are rich in anserine and creatine, which are useful for human health care, along with collagen and lipids. The important factors in increasing these useful substances and manage the environment of salmoniformes aquaculture should be noted.

Cardiac magnetic resonance characterization and prediction of left ventricular thrombus after ST-segment elevation myocardial infarction

Abstract Background Left ventricular thrombus (LVTh) is an uncommon yet serious complication after ST-segment elevation myocardial infarction (STEMI). Late gadolinium enhancement (LGE) sequences in cardiac magnetic resonance (CMR) imaging allows for accurate detection of LVTh. However, the implications of CMR to predict and characterize LVTh occurrence is this population is unclear. Purpose We aim to characterize the incidence, outcomes, and predictors of LVTh after STEMI by CMR imaging. Methods Our registry comprised 455 patients admitted for a first reperfused STEMI in our university hospital. Baseline characteristics were recorded. All patients underwent early (1-week) and late (6-month) CMR. Left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments) were measured. LGE sequences were used to analyze the presence of LVTh. Patients with LVTh at 6-month CMR underwent an additional CMR 1 year after admission. Univariate and multivariate comparisons were performed to study the ocurrence of LVTh in the first 6 months after STEMI. Results Mean age was 58.24±11.69 years, most patients were male (82.6%) and anterior infarction occurred in more than half of the cohort (52.7%). LVTh was detected in 36 (7.9%) patients in the first 6 months after STEMI. Anticoagulation was initiated in all cases. Of these, 27 patients had LVTh at early (1-week) CMR, but 9 had LVTh at late (6-month) CMR with no prior evidence of LVTh at early CMR. A total of 6 patients had persisting LVTh at 1-year CMR (37.5% of patients with 6-month LVTh). In multivariable analysis, anterior infarction (HR 6.6 [1.91–22.83], p<0.001) and 1-week CMR-LVEF (HR 0.97 [0.93–0.99], p=0.04) and MVO (HR 1.19 [1.02–1.39], p=0.03) independently predicted the occurrence of LVTh in the first 6 months after STEMI. We computed a risk score of LVTh assigning 1 point to each of these variables (anterior infarction, CMR-LVEF <50% and MVO >3.5 segments), which allowed us to stratify the risk of LVTh in the first 6 months after STEMI (0.6% if 0 points, 3.8% if 1 point, 14.4% if 2 points, and 31.2% if 3 points). Conclusions CMR imaging soon after STEMI can contribute relevant prognostic value regarding LVTh occurrence after the acute event. Patients with anterior infarction, LVEF <50% and MVO in >3.5 segments at early (1-week) CMR have the highest risk of LVTh in the first 6 months after STEMI. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Instituto de Salud Carlos III and “Fondos Europeos de Desarrollo Regional FEDER” and Conselleria de Educaciόn – Generalitat Valenciana.

Impact of compressed sensing (CS) acceleration of two-dimensional (2D) flow sequences in clinical paediatric cardiac magnetic resonance (CMR)

Abstract Background Two-dimensional (2D) through-plane phase-contrast (PC) cine flow imaging assesses shunts and valve regurgitations in paediatric CMR, and is considered the reference standard for Clinical quantification Of blood Flow (COF). However, the longer breath-hold (BH) for a flow cine can reduce patient compliance with possibly large respiratory maneuvers altering flow. Compressed sensing (CS) flow has not been widely evaluated in pediatric clinical CMR, although CS flow reduces scan time with persistent accuracy [1–3]. Kocaoglu et al applied CS to ascending and descending aorta and SVC with good results. We used main pulmonary artery (MPA) and sinotubular junction (STJ) planes as usual for clinical CMR. Purpose We hypothesise that reduced BH time by modest application of CS to 2D cine through-plane flows (Short BH quantification of Flow) (SBOF) retains accuracy while enabling faster and potentially more reliable paediatric flows. We therefore investigate the variance between conventional COF and new SBOF cine flows in paediatric CMR. Methods Paediatric patients were enrolled. Aortic (AO) and MPA COFs were planned from cines of the left and right ventricular outflow tracts. For AO flow the plane was placed at the STJ, and MPA flow was acquired above the pulmonary valve. The same planes were used for COF and SBOF flows at nominally similar parameters except the moderate application of CS exploiting redundancy across the cine frames, SBOF being segmented CS cines not real-time. CVI42 (5.10; Circle CVI) was used for flow analysis (single observer, 3 years' experience). Paired t-tests found the overall differences, and variability was defined at ±2SD for STJSV, MPASV, STJCO, MPACO, and Qp/Qs. Results and discussion 20 patients (mean age 13.7, range 10–17y) were enrolled (12 CHDs, 7 cardiomyopathies or other diseases). The BH times were COF mean 11.7s (range 8.4–20.9s) vs SBOF mean 6.5s (min 3.6–9.1s). For STJ flows the differences and variabilities between the COF and SBOF flows were SV 6.95±13.6 (ml/beat), CO 0.16±1.35 (l/min) and for MPA flows SV 2.95±12.3 (ml/beat), CO 0.27±0.96 (l/min) and for Qp/Qs were 0.04±0.19 by ml/beat and 0.02±0.23 by l/min. The mean differences were non significant, and variability between SBOF and COF was similar to intrasession repeatability of COF in a separate paediatric population at our centre (unpublished), that might arise from physiological flow changes, possibly in terms of pre and post load and heart rate. With shorter BHs also assisting patient compliance of the SBOF, physiological flow effects might be reduced, although given the variability in COV this was unconfirmed. Conclusion Moderate CS applied to clinical segmented-cine paediatric phase-contrast flows in the STJ and MPA planes did not degrade flow repeatability or cause bias. SBOF assists clinical flows by shorter BHs and also may aid compliance and reduce physiological variations. Funding Acknowledgement Type of funding sources: None.

A comparative study of conventional magnetic resonance sequences with 2D time of flight sequence versus contrast enhanced magnetic resonance venography in diagnosing cerebral venous sinus thrombosis

Background: The present study aimed to compare the accuracy between conventional MRV with 2D Time of Flight sequence versus contrast enhanced MRV in Cerebral venous sinus thrombosis.Materials and methods: This was a hospital based ambispective study that was conducted from Jan 2021 to Jun 2022 in Department of Radiodiagnosis in Mahatma Gandhi Medical College and Research Institute (MGMCRI), Pondicherry after obtaining approval from Ethical Committee. Patients admitted in MGMCRI as clinically suspected cases of CVT was included for the study. It was an ambispective study, so included records of patients retrospectively from JAN 2019 to DEC 2020 and prospectively from JAN 2021 to MAY 2022 in Mahatma Gandhi Medical College and Research Institute.Results: The study was conducted as a hospital based ambispective study comprising 30 patients of either sex.Majority of the study participants were in the age group of less than 25 years and were females (73.3%). Majority of the female study participants were in puerperium. Majority of the study patients had headache on presentation (73.3%). Sensitivity and specificity of MR TOF in diagnosing SSS thrombosis was 92.31% and 50% respectively. Sensitivity and specificity of MR TOF in diagnosing LS thrombosis was 79.17% and 33.33% respectively. Sensitivity and specificity of MR TOF in diagnosing STS thrombosis was 100% and 34.78% respectively.Conclusion: Multicentric large scale studies involving patients from different backgrounds of variable demography was required to clearly establish the accuracy of MRI investigations. The performance of contrast enhanced 3D MRV was superior in terms of picture quality and evaluation of all sinuses and veins. The findings of our study contributed to the body of data supporting the advantages of contrast enhanced 3D MR venography over 2D TOF MR Venography in the routine clinical diagnosis or exclusion of acute CVT.

Quantitative assessment of lumbar spine bone marrow in patients with different severity of CKD by IDEAL-IQ magnetic resonance sequence.

BackgroundChronic kidney disease (CKD) has a significant negative impact on bone health. Bone marrow is an essential component of bone, mainly composed of trabecular bone and fat. The IDEAL-IQ sequence of MRI allows indirect quantification of trabecular bone mass by R2* and direct quantification of bone marrow fat content by FF map, respectively.ObjectiveOur objective was to explore the association of CKD severity with bone marrow using IDEAL-IQ and whether mineral and bone metabolism markers alter this association.MethodWe recruited 68 CKD patients in this cross-sectional research (15 with CKD stages 3-4, 26 with stage 5, and 27 with stage 5d). All patients underwent lumbar spine IDEAL-IQ, BMD, and several bone metabolism markers (iPTH, 25-(OH)-VitD, calcium and phosphorus). Multiple linear regression analysis was used to examine the association of CKD severity with MRI measurements (R2* and FF).ResultsMore severe CKD was associated with a higher R2* value [CKD 5d versus 3-4: 30.077 s-1 (95% CI: 12.937, 47.217), P for trend < 0.001], and this association was attenuated when iPTH was introduced [CKD 5d versus 3-4: 19.660 s-1 (95% CI: 0.205, 39.114), P for trend = 0.042]. Furthermore, iPTH had an association with R2* value [iPTH (pg/mL): 0.033 s-1 (95% CI: 0.001, 0.064), P = 0.041]. Besides, FF was mainly affected by age and BMI, but not CKD.ConclusionsThe bone marrow R2* value measured by IDEAL-IQ sequence is associated with CKD severity and iPTH. The R2* of IDEAL-IQ has the potential to reflect lumbar bone changes in patients with CKD.

Impact of Prosthetic Valve Regurgitation Assessed by Echocardiography and Magnetic Resonance Imaging on Long-Term Clinical Outcomes after TAVR

Background: Prosthetic valve regurgitation (PVR) impairs early and mid-term outcomes after transcatheter aortic valve replacement (TAVR). We explored the impact of PVR assessed by transthoracic echocardiography (TTE) and magnetic resonance imaging-regurgitation fraction (MRI-RF) on long-term clinical outcomes. Methods: PVR was assessed by TTE applying the Valve Academic Research Consortium criteria and MRI-RF (from velocity-encoded phase contrast magnetic resonance sequence) in 424 patients. Results: MRI-RF correlated modestly with the echocardiographic grades of PVR (Spearman’s rank correlation coefficient = 0.32, p < 0.001). Using an MRI-RF ≥20% to define ≥ moderate PVR, echocardiography and MRI-RF agreed on PVR classification in 412 patients (97.2%; kappa statistic = 0.56, p < 0.001). Five-year mortality or reintervention was higher in patients with echocardiographic ≥ moderate PVR (83.3% vs. 45.0%, log rank p value = 0.002; HR [95% CI]: 3.18 [1.48–6.84]) as well as in patients with MRI-RF ≥20% (79.3% vs. 43.2%, log rank p value <0.001; HR [95% CI]: 2.68 [1.53–4.70]), while the outcomes of patients with echocardiographic mild PVR were not significantly different from those with none-trace PVR. In the two latter groups (echocardiographic < moderate PVR), MRI-RF ≥20% was associated with a significantly higher 5-year mortality or reintervention as compared with MRI-RF <20% (79.5% vs. 42.2%, log rank p value = 0.023; HR [95% CI]: 2.26 [1.10–4.65]). Conclusions: Greater than mild PVR as defined by TTE or MRI-RF is associated with impaired long-term clinical outcomes after TAVR. MRI-RF can be used to further risk-stratify patients with echocardiographic less-than-moderate PVR.

Refocus flip angle modulation on the pd tse sequences in the magnetic resonance imaging of the knee, for the evaluation of meniscal injuries

The Radiofrequency Refocused Echo Spin-Echo Echo-Train Rapid-Acquisition sequences, known as Turbo Spin Echo(TSE) or Fast Spin Echo (FSE) are the most commonly used sequences in Magnetic Resonance as they provide anotable contribution in morphological and anatomical terms, thanks to their high spatial and contrast resolution.Furthermore, they allow a higher signal noise ratio than the other families of sequences thanks to the numerous refocusing pulses and thanks to a TR so long as to allow sampling as many K-space phase encodings as possible and witha complete recovery of the Longitudinal Magnetization. Finally, the multiple 180 ° pulses of these sequences reducethe inhomogeneities of the Magnetic Field by minimizing the phenomena of magnetic susceptibility. However, theirapplication, especially in scanners with a high intensity of static magnetic field B0 (1.5T and/or 3T) is prevented bythe deposition of RF due to the long echo trains, which sometimes involve exceeding the limits of the specific absorption rate (SAR) for patient safety. Over time, a common solution to the SAR problem has been the use of refocusingangles smaller than 180 ° (160 °-140 °-120 °), which lead to its reduction at the cost, however, of an obvious penaltyin terms of signal-to-noise ratio (SNR). In this study we present a modulation method of the Refocus Flip Angle applied to the DP-TSE sequences in the evaluation of meniscal lesions in the study protocol of the Magnetic Resonanceof the Knee, which exploits the phenomenon of the Pseudo-Steady-State (PSS), leading to a noticeable SAR reductionwithout loss of SNR and also providing excellent contrast resolution.

Magnetic resonance imaging characteristics of polypoid endometriosis and review of the literature.

Polypoid endometriosis is a rare variant of endometriosis and may mimic malignancy. The purpose of this study is to evaluate magnetic resonance (MR) imaging characteristics of polypoid endometriosis for the differential diagnosis with malignancy. MR imaging findings of four histologically proven polypoid endometriosis were retrospectively evaluated with the review of the literature. All polypoid endometriosis exhibited high signal intensity on T2-weighted images reflecting abundant dilated endometrial glands. Peritoneal lesions were surrounded by low signal intensity rim represented the "black rim sign" reflecting endometriotic fibrous adhesion. Two cases arising from endometriotic cysts showed transmural extension (peritoneal extension and myometrial infiltration). Endometriotic hemorrhagic foci were demonstrated in four lesions as high signal intensity on T1-weighted images and/or susceptibility-induced signal voids on susceptibility-weighted MR sequence. Diffusion-weighted images showed high signal intensity with relatively high apparent diffusion coefficient (ADC) due to T2 shine-through effect but no diffusion restriction, and dynamic contrast-enhanced (DCE) MR imaging showed gradually increasing contrast-enhancement pattern like benign pathologies. Polypoid endometriosis may mimic malignancy; however, black rim sign may be a characteristic MR imaging finding for the peritoneal lesions, and no diffusion restriction and gradually increasing contrast-enhancement pattern may reflect its benign nature.

Diagnostic performance of synthetic magnetic resonance imaging in the prognostic evaluation of rectal cancer.

Numerous factors are related to the prognosis of rectal cancer, including T stage, N stage, metastasis, extramural venous invasion (EMVI), circumferential resection margin (CRM), and tumor differentiation. However, it is still a challenge to precisely evaluate them before therapy; therefore, we investigate whether synthetic magnetic resonance imaging and apparent diffusion coefficient (ADC) values could help predict the prognostic factors of rectal cancer. Eighty-seven patients (55 men and 32 women; mean age, 59±11 years) with pathologically confirmed rectal cancer were enrolled. Preoperative quantitative metrics, including T1, T2, proton density (PD), and ADC values, were measured with diffusion-weighted imaging (DWI) acquired by a single-shot echo-planar sequence and synthetic magnetic resonance imaging acquired by a multi-dynamic multi-echo sequence at 3.0 T, in patients with rectal cancer by two radiologists. We evaluated the diagnostic performance of synthetic magnetic resonance imaging using the independent sample t-test or Mann-Whitney U test and receiver operating characteristic (ROC) curve and multivariate logistic regression analyses and compared the area under the ROC curve of quantitative values using the DeLong test. The T2 and PD values showed a significant reduction among patients with poor differentiation and lymph node metastasis in rectal cancer. The area under the ROC curve values of T2 and PD values for predicting magnetic resonance imaging N stage and differentiation were 0.734, 0.682, and 0.673, 0.686, respectively. Moreover, combining T2 and PD values for magnetic resonance imaging N stage slightly improved the area under the ROC curve value of 0.774 (95% CI, 0.673-0.876). In the present study, the ADC and T1 values were not significant in the differentiation or clinical stage of rectal cancer (RC). Quantitative T2 and PD values obtained by synthetic magnetic resonance imaging might be used for evaluating prognostic factors of rectal cancer noninvasively. Furthermore, combining T2 and PD values further improved the diagnostic performance of magnetic resonance imaging N staging in rectal cancer. The ADC and T1 values were not significant in the differentiation or clinical stage of RC.

HGG-19. Co-occurrences of a high-grade glioma with cavernous malformations and pathogenic variants inPDCD10 andSMARCA4

INTRODUCTION: The co-occurrence of multiple disease processes can make for more challenging diagnoses. Here we report an unusual case of a patient found to have an IDH1-mutant high-grade glioma along with multiple cerebral cavernous malformations and pathogenic germline variants in PDCD10 and SMARCA4. CASE DESCRIPTION: A 17-year-old female presented with left arm paresthesia and weakness along with persistent headaches within the frontal and occipital regions that progressed in intensity to include nausea and emesis. A fast sequence magnetic resonance imaging (MRI) of her head was obtained that revealed the presence of multiple bilateral cystic lesions suspicious for cavernomas, with the most notable lesion in the right parietal lobe. Ophthalmology consultation revealed grade III papilledema bilaterally. A full brain MRI with and without contrast was obtained and demonstrated a right anterior parietal lobe lesion with associated mass effect, as well as multiple bilateral supratentorial and left cerebellar cavernous malformations. The patient underwent tumor debulking of her dominant lesion. Pathology revealed an IDH1-mutant diffuse astrocytoma, WHO grade III. Tumor genetic testing was done and identified a SMARCA4 and two TP53 variants. Germline genetic testing was then pursued which revealed a PDCD10 pathogenic variant consistent with familial cerebral cavernous malformation syndrome and a likely pathogenic variant in SMARCA4. Treatment of her high-grade-glioma included radiation therapy followed by maintenance oral temozolomide. DISCUSSION: This case illustrates the unusual co-occurrences of a high-grade glioma with familial cavernous malformation syndrome and germline pathogenic variants in PDCD10 and SMARCA4. Our patient continues to do well clinically, but because of her risk of developing small cell carcinoma of the ovary she has elected to undergo a prophylactic bilateral salpingo-oophorectomy. Recognition of abnormal genetic results is critical in the setting of multiple disease processes and can play a crucial role in the on-going care for a patient.

A Novel Framework With Weighted Decision Map Based on Convolutional Neural Network for Cardiac MR Segmentation.

For diagnosing cardiovascular disease, an accurate segmentation method is needed. There are several unresolved issues in the complex field of cardiac magnetic resonance imaging, some of which have been partially addressed by using deep neural networks. To solve two problems of over-segmentation and under-segmentation of anatomical shapes in the short-axis view from different cardiac magnetic resonance sequences, we propose a novel two-stage framework with a weighted decision map based on convolutional neural networks to segment the myocardium (Myo), left ventricle (LV), and right ventricle (RV) simultaneously. The framework comprises a decision map extractor and a cardiac segmenter. A cascaded U-Net++ is used as a decision map extractor to acquire the decision map that decides the category of each pixel. Cardiac segmenter is a multiscale dual-path feature aggregation network (MDFA-Net) which consists of a densely connected network and an asymmetric encoding and decoding network. The input to the cardiac segmenter is derived from processed original images weighted by the output of the decision map extractor. We conducted experiments on two datasets of multi-sequence cardiac magnetic resonance segmentation challenge 2019 (MS-CMRSeg 2019) and myocardial pathology segmentation challenge 2020 (MyoPS 2020). Test results obtained on MyoPS 2020 show that the average Dice coefficients of the proposed method on the segmentation tasks of Myo, LV and RV are 84.70%, 86.00%, and 86.31%, respectively.

Detection of Ablation Boundaries Using Different MR Sequences in a Swine Liver Model

PurposeTo determine the magnetic resonance (MR) sequences best suited for the assessment of ablation zones after radiofrequency ablation (RFA).MethodsThree percutaneous MR-guided RFA of the liver were performed on three swine. Four pre-contrast and two hepatobiliary post-contrast sequences were obtained after ablation. Tissue samples were extracted and stained for nicotinamide adenine dinucleotide diaphorase hydride (NADH) and with hematoxylin and eosin. Post-ablation MR images and NADH slides were segmented to determine the total ablation zone, their Dice similarity coefficient (DSC), and the contrast-to-noise ratio (CNR) of the visible ablation boundary to normal liver tissue.ResultsTwo distinct layers were combined to determine the ablation zone: an inner layer of coagulation necrosis and an outer layer defined as the peripheral transition zone. Corresponding zones could be found in the MR images as well. Compared to histology, the total area of the MR ablation zone was significantly smaller on the pre-contrast T1 images (p < 0.01) and significantly larger with T2 turbo spin-echo (p = 0.025). No significant difference in size of the ablation zone depiction could be found between histology, post-contrast T1 volumetric interpolated breath-hold examination (VIBE), and post-contrast T1 3D Turboflash (TFL) as well as T2 SPACE images. All sequences but the pre-contrast T1 VIBE sequence showed a DSC above 80% and a high CNR.ConclusionsPost-contrast T1 3DTFL performs best when assessing ablation zones after RFA. Since the sequence requires a long acquisition time, T1 VIBE post-contrast offers the best compromise between acquisition time and estimation accuracy.

Diagnostic accuracy of a fast MRI T2-sequence for the diagnosis of internal herniation after Roux-and-Y gastric bypass during pregnancy: A retrospective single center study

PurposeThe objective of this retrospective study was to evaluate the diagnostic accuracy of a fast sequence Magnetic Resonance Imaging (MRI) sequence, T2- half-Fourier acquisition single-shot turbo spin echo (HASTE) for the diagnosis of internal herniation (IH) in pregnant patients with a history of Roux-en-Y gastric bypass (RYGB). MethodsAbdominal MRI studies, performed for the clinical suspicion of IH of pregnant patients with a history of RYGB, were analyzed by two abdominal radiologists. Thirty-one cases were included and for each case both readers independently evaluated the T2 HASTE sequence in different planes (axial, coronal and sagittal) to determine the presence or absence of IH. Diagnostic performance of T2 HASTE MRI was evaluated by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy compared to the clinical diagnosis of IH as the gold standard. IH was diagnosed as the presence of herniated bowel through the mesenteric defect at the time of surgical exploration. IH was deemed absent if the surgical exploration showed no herniated bowel or if patients had no subsequent clinical symptoms of IH after 90 days of clinical follow-up. ResultsThe results in this study, with 16 patients with IH and 15 patients without IH, portray a high accuracy for the detection of IH, ranging from 87.9% to 90.3%. This fast T2 sequence shows a high NPV (86.7% - 100.0% 87.7), sensitivity (88.9% - 100.0%) and specificity (80.0% - 86.7%). This study also portrayed a substantial interobserver agreement (0.741) for the evaluation of IH. ConclusionT2 HASTE MRI shows an excellent sensitivity and NPV for the detection of IH in pregnant patients. The fast acquisition time makes this sequence useful in the emergency setting, and it can be used for the diagnosis or exclusion of IH in pregnant patients.

Measuring Strain in Diffusion-Weighted Data Using Tagged Magnetic Resonance Imaging.

Accurate strain measurement in a deforming organ has been essential in motion analysis using medical images. In recent years, internal tissue's in vivo motion and strain computation has been mostly achieved through dynamic magnetic resonance (MR) imaging. However, such data lack information on tissue's intrinsic fiber directions, preventing computed strain tensors from being projected onto a direction of interest. Although diffusion-weighted MR imaging excels at providing fiber tractography, it yields static images unmatched with dynamic MR data. This work reports an algorithm workflow that estimates strain values in the diffusion MR space by matching corresponding tagged dynamic MR images. We focus on processing a dataset of various human tongue deformations in speech. The geometry of tongue muscle fibers is provided by diffusion tractography, while spatiotemporal motion fields are provided by tagged MR analysis. The tongue's deforming shapes are determined by segmenting a synthetic cine dynamic MR sequence generated from tagged data using a deep neural network. Estimated motion fields are transformed into the diffusion MR space using diffeomorphic registration, eventually leading to strain values computed in the direction of muscle fibers. The method was tested on 78 time volumes acquired during three sets of specific tongue deformations including both speech and protrusion motion. Strain in the line of action of seven internal tongue muscles was extracted and compared both intra- and inter-subject. Resulting compression and stretching patterns of individual muscles revealed the unique behavior of individual muscles and their potential activation pattern.

Contrast-enhanced double inversion recovery sequence for patients with multiple sclerosis: feasibility of subtraction images between pre- and post-contrast images.

Few reports have examined the feasibility of a post-contrast double inversion recovery (DIR) magnetic resonance (MR) sequence in patients with multiple sclerosis (MS) because of partial or complete signal loss of enhancing MS lesions. To compare subtracted images of DIR (pre-contrast - post-contrast DIR images) with contrast enhanced T1-weighted (CE-T1W) images in the depiction of contrast enhancement of MS lesions. In total, 27 patients were included. Two neuroradiologists interpreted both images of CE-T1W imaging and subtracted DIR, and interpretation of the images was classified into a score of 1-5 (from 5, definitely superior contrast of lesions on DIR subtraction compared to conventional CE-T1W imaging, to 1, definitely superior contrast of lesions on CE-T1W imaging. The interrater agreement (κ coefficient) was measured. The signal-to-noise ratio (SNR) and contrast-noise-ratio (CNR) of the lesion were compared. A significant difference (P < 0.001) in scoring was seen between conventional CE-T1W imaging (2.1 ± 1.5 with one reviewer and 2.4 ± 1.5 with the other) and DIR subtraction (4.4 ± 1.0 with one reviewer and 4.7 ± 0.8 with the other). SNR from conventional CE-T1W imaging (24.8 ± 14.7) was significantly superior to that from DIR subtraction (4.0 ± 1.0; P < 0.001). CNR in DIR subtraction (326.4 ± 250.0) was significantly superior to that in conventional CE-T1W imaging (0.8 ± 5.5; P < 0.001). For interrater agreement in the evaluation of contrast enhancement of the lesions, κ coefficients were 0.84 for conventional CE-T1W imaging and 0.72 for DIR subtraction. Subtracted DIR image enables more obvious contrast enhancement of the MS lesions compared with conventional CE-T1W imaging.

3-Dimensional Fluid and White Matter Suppression Magnetic Resonance Imaging Sequence Accelerated With Compressed Sensing Improves Multiple Sclerosis Cervical Spinal Cord Lesion Detection Compared With Standard 2-Dimensional Imaging.

Fluid and white matter suppression (FLAWS) is a recently proposed magnetic resonance sequence derived from magnetization-prepared 2 rapid acquisition gradient-echo providing 2 coregistered datasets with white matter- and cerebrospinal fluid-suppressed signal, enabling synthetic imaging with amplified contrast. Although these features are high potential for brain multiple sclerosis (MS) imaging, spinal cord has never been evaluated with this sequence to date. The objective of this work was therefore to assess diagnostic performance and self-confidence provided by compressed-sensing (CS) 3-dimensional (3D) FLAWS for cervical MS lesion detection on a head scan that includes the cervical cord without changing standard procedures. Prospective 3 T scans (MS first diagnosis or follow-up) acquired between 2019 and 2020 were retrospectively analyzed. All patients underwent 3D CS-FLAWS (duration: 5 minutes 40 seconds), axial T 2 turbo spin echo covering cervical spine from cervicomedullary junction to the same inferior level as FLAWS, and sagittal cervical T 2 /short tau inversion recovery imaging. Two readers performed a 2-stage double-blind reading, followed by consensus reading. Wilcoxon tests were used to compare the number of detected spinal cord lesions and the reader's diagnostic self-confidence when using FLAWS versus the reference 2D T 2 -weighted imaging. Fifty-eight patients were included (mean age, 40 ± 13 years, 46 women, 7 ± 6 years mean disease duration). The CS-FLAWS detected significantly more lesions than the reference T 2 -weighted imaging (197 vs 152 detected lesions, P < 0.001), with a sensitivity of 98% (T 2 -weighted imaging sensitivity: 90%) after consensual reading. Considering the subgroup of patients who underwent sagittal T2 + short tau inversion recovery imaging (Magnetic Resonance Imaging for Multiple Sclerosis subgroup), +250% lesions were detected with FLAWS (63 vs 25 lesions detected, P < 0.001). Mean reading self-confidence was significantly better with CS-FLAWS (median, 5 [interquartile range, 1] [no doubt for diagnosis] vs 4 [interquartile range, 1] [high confidence]; P < 0.001). Imaging with CS-FLAWS provides an improved cervical spinal cord exploration for MS with increased self-confidence compared with conventional T 2 -weighted imaging, in a clinically acceptable time.

Can Metal Artifact Reduction Sequence Magnetic Resonance Imaging (MARS-MRI) Help In The Diagnosis Of Periprosthetic Shoulder Infection?

The purpose of our study was to determine the reliability, repeatability, and diagnostic performance of metal artifact reduction magnetic resonance imaging (MARS-MRI) findings for the diagnosis of peri-prosthetic shoulder infection (PSI).

State-of-the-art myocardial strain by CMR feature tracking: clinical applications and future perspectives.

Based on conventional cine sequences of cardiac magnetic resonance (CMR), feature tracking (FT) is an emerging tissue tracking technique that evaluates myocardial motion and deformation quantitatively by strain, strain rate, torsion, and dyssynchrony. It has been widely accepted in modern literature that strain analysis can offer incremental information in addition to classic global and segmental functional analysis. Furthermore, CMR-FT facilitates measurement of all cardiac chambers, including the relatively thin-walled atria and the right ventricle, which has been a difficult measurement to obtain with the reference standard technique of myocardial tagging. CMR-FT objectively quantifies cardiovascular impairment and characterizes myocardial function in a novel way through direct assessment of myocardial fiber deformation. The purpose of this review is to discuss the current status of clinical applications of myocardial strain by CMR-FT in a variety of cardiovascular diseases. KEY POINTS: • CMR-FT is of great value for differential diagnosis and provides incremental value for evaluating the progression and severity of diseases. • CMR-FT guides the early diagnosis of various cardiovascular diseases and provides the possibility for the early detection of myocardial impairment and additional information regarding subclinical cardiac abnormalities. • Direct assessment of myocardial fiber deformation using CMR-FT has the potential to provide prognostic information incremental to common clinical and CMR risk factors.