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The purpose of this study was to evaluate the image quality of compressed-sensing accelerated single-shot fast spin-echo (SSFSECS) sequences acquired within a single breath-hold in comparison with conventional SSFSE (SSFSECONV) and multishot TSE (mTSE). A total of 101 patients who underwent liver MRI at 3 T, including SSFSECONV (acquisition time (TA) = 58−62 s), mTSE (TA = 108 s), and SSFSECS (TA = 18 s), were included in this retrospective study. Two radiologists assessed the three sequences with respect to artifacts, organ sharpness, small structure visibility, overall image quality, and conspicuity of main lesions of liver and pancreas using a five-point evaluation scale system. Descriptive statistics and the Wilcoxon signed-rank test were used for statistical analysis. SSFSECS was significantly better than SSFSECONV and mTSE for artifacts, small structure visibility, overall image quality, and conspicuity of main lesions (p < 0.005). Regarding organ sharpness, mTSE and SSFSECS did not significantly differ (p = 0.554). Conspicuity of liver lesion did not significantly differ between SSFSECONV and mTSE (p = 0.404). SSFSECS showed superior image quality compared with SSFSECONV and mTSE despite a more than three-fold reduction in TA, suggesting a remarkable potential for saving time in liver imaging.

Purpose: To investigate the clinical feasibility of accelerated free-breathing stack-of-spirals (spiral) three-dimensional (3D) ultrashort echo time (UTE) lung magnetic resonance imaging (MRI) using iterative self-consistent parallel imaging reconstruction from arbitrary k-space (SPIRiT) algorithm in patients with breast cancer., Methods: The institutional review board approved this prospective study and patients' informed consents were obtained. Between June and August 2018, 29 female patients with breast cancer underwent 3-T MRI including accelerated free-breathing spiral 3D UTE (0.98-mm isotropic spatial resolution; echo time, 0.05 msec) of the lungs and thin-section chest computed tomography (CT). Two radiologists evaluated the image quality and pulmonary nodules on MRI were assessed and compared, CT as a reference., Results: The pulmonary vessels and bronchi were visible consistently up to the sub-sub-segmental and sub-segmental branch levels, respectively, on accelerated spiral 3D UTE. The overall image quality was evaluated as good and excellent for 70.7% of accelerated spiral 3D UTE images (reviewer [R]1, 72.4% [21/29]; R2, 69.0% [20/29]) and acceptable for 20.7% (both R1 and R2, 20.7% [6/29]). Five patients on CT revealed 141 pulmonary metastatic nodules (5.3 ± 2.6 mm); the overall nodule detection rate of accelerated spiral 3D UTE was sensitivity of 90.8% (128/141), accuracy of 87.7%, and positive predictive value of 96.2%. In the Bland-Altman plot analysis comparing nodule size between CT and MRI, 132/141 nodules (93.6%) were inside the limits of agreement., Conclusion: Accelerated free-breathing spiral 3D UTE using the SPIRiT algorithm could be a potential alternative to CT for oncology patients., Competing Interests: TB, JP, and MYP are employed by Siemens Healthcare. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Cha, Ahn, Choi, Park, Benkert, Pfeuffer and Paek.)

Objective: Motion-corrected averaging with a single-shot technique was introduced for faster acquisition of late-gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging while free-breathing. We aimed to evaluate the image quality (IQ) of free-breathing motion-corrected single-shot LGE (moco-ss-LGE) in patients with hypertrophic cardiomyopathy (HCM)., Materials and Methods: Between April and December 2019, 30 patients (23 men; median age, 48.5; interquartile range [IQR], 36.5-61.3) with HCM were prospectively enrolled. Breath-held single-shot LGE (bh-ss-LGE) and free-breathing moco-ss-LGE images were acquired in random order on a 3T MR system. Semi-quantitative IQ scores, contrast-to-noise ratios (CNRs), and quantitative size of myocardial scar were assessed on pairs of bh-ss-LGE and moco-ss-LGE. The mean ± standard deviation of the parameters was obtained. The results were compared using the Wilcoxon signed-rank test., Results: The moco-ss-LGE images had better IQ scores than the bh-ss-LGE images (4.55 ± 0.55 vs. 3.68 ± 0.45, p < 0.001). The CNR of the scar to the remote myocardium (34.46 ± 11.85 vs. 26.13 ± 10.04, p < 0.001), scar to left ventricle (LV) cavity (13.09 ± 7.95 vs. 9.84 ± 6.65, p = 0.030), and LV cavity to remote myocardium (33.12 ± 15.53 vs. 22.69 ± 11.27, p < 0.001) were consistently greater for moco-ss-LGE images than for bh-ss-LGE images. Measurements of scar size did not differ significantly between LGE pairs using the following three different quantification methods: 1) full width at half-maximum method; 23.84 ± 12.88% vs. 24.05 ± 12.81% ( p = 0.820), 2) 6-standard deviation method, 15.14 ± 10.78% vs. 15.99 ± 10.99% ( p = 0.186), and 3) 3-standard deviation method; 36.51 ± 17.60% vs. 37.50 ± 17.90% ( p = 0.785)., Conclusion: Motion-corrected averaging may allow for superior IQ and CNRs with free-breathing in single-shot LGE imaging, with a herald of free-breathing moco-ss-LGE as the scar imaging technique of choice for clinical practice., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2021 The Korean Society of Radiology.)

Magnetic resonance cholangiopancreatography (MRCP) has been widely used in clinical practice, and recently developed compressed-sensing accelerated MRCP (CS-MRCP) has shown great potential in shortening the acquisition time. The purpose of this prospective study was to evaluate the clinical feasibility and image quality of optimized breath-hold CS-MRCP (BH-CS-MRCP) and conventional navigator-triggered MRCP. Data from 124 consecutive patients with suspected pancreaticobiliary diseases were analyzed by two radiologists using a five-point Likert-type scale. Communication between a cyst and the pancreatic duct (PD) was analyzed. Signal-to-noise ratio (SNR) of the common bile duct (CBD), contrast ratio between the CBD and periductal tissue, and contrast-to-noise ratio (CNR) of the CBD and liver were measured. Optimized BH-CS-MRCP showed significantly fewer artifacts with better background suppression and overall image quality. Optimized BH-CS-MRCP demonstrated communication between a cyst and the PD better than conventional MRCP (96.7% vs. 76.7%, p = 0.048). SNR, contrast ratio, and CNR were significantly higher with optimized BH-CS-MRCP ( p < 0.001). Optimized BH-CS-MRCP showed comparable or even better image quality than conventional MRCP, with improved visualization of communication between a cyst and the PD., Competing Interests: The authors declare no conflicts of interest.

Background: Metastasis and multiple myeloma are common malignant bone marrow lesions which may be difficult to distinguish because of similar imaging findings. The purpose of this study was to determine the value of adding diffusion-weighted imaging (DWI) to standard MR imaging to differentiate multiple myeloma from metastasis., Methods: 25 patients with metastasis and 18 patients with multiple myeloma underwent 3T MR imaging with DWI (b = 0, 800 s/mm2) were enrolled. They all had pathologically confirmed bone lesions and were in a treatment naïve state. Two readers who were blind of final diagnosis measured the average ADC (ADCav) and minimum ADC (ADCmin) on the DWI. They then estimated the diagnosis, based on the standard MR imaging and measured ADC values. Another reader performed histogram analysis on the whole tumor volume and obtained mean ADC (ADCvol), standard deviation (SDvol), skewness, and kurtosis. Comparison of the obtained values from DWI was performed by the t-test or Mann-Whitney U test. The receiver operating characteristic (ROC) curve with areas under the curve (AUC) was used to obtain the cut off values and to evaluate the diagnostic performance of the two readers., Results: ADCav, ADCmin, and ADCvol of multiple myeloma were significantly lower than those of metastasis: ADCav, 752 μm2/sec versus 1081 μm2/sec; ADCmin, 704 μm2/sec vs 835 μm2/sec; ADCvol 761 μm2/sec vs 1184 μm2/sec (p < .001). In histogram analysis, ADC values of multiple myeloma showed narrow distribution than metastasis: SDvol, 144 vs 257 (p < .001). Areas under the receiver operating characteristic curve was significantly higher with additive DWI than standard MR alone: 0.762 vs 0.953; 0.706 vs 0.950 (p < .05) for two readers., Conclusions: This study suggested that the addition of axial DWI to standard MR imaging can be helpful to diagnose multiple myeloma from metastasis at 3T., Competing Interests: All the authors are nothing to declare. In this study, we used software (WIP) provided by Siemens Healthcare Ltd and received some advices about this software from some of authors working at the company. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

A reliable, non-invasive diagnostic method is needed for early detection and serial monitoring of cardiotoxicity, a well-known side effect of chemotherapy. This study aimed to assess the feasibility of T1-mapping cardiac magnetic resonance imaging (CMR) for evaluating subclinical myocardial changes in a doxorubicin-induced cardiotoxicity rabbit model. Adult male New Zealand White rabbits were injected twice-weekly with doxorubicin and subjected to CMR on a clinical 3T MR system before and every 2-4 weeks post-drug administration. Native T1 and extracellular volume (ECV) values were measured at six mid-left ventricle (LV) and specific LV lesions. Histological assessments evaluated myocardial injury and fibrosis. Three pre-model and 11 post-model animals were included. Myocardial injury was observed from 3 weeks. Mean LV myocardium ECV values increased significantly from week 3 before LV ejection fraction decreases (week 6), and ECVs of the RV upper/lower insertion sites and papillary muscle exceeded those of the LV. The mean native T1 value in the mid-LV increased significantly increased from week 6, and LV myocardium ECV correlated strongly with the degree of fibrosis (r = 0.979, p < 0.001). Myocardial T1 mapping, particularly ECV values, reliably and non-invasively detected early cardiotoxicity, allowing serial monitoring of chemotherapy-induced cardiotoxicity.

Objectives: This study sought to evaluate whether patterns of myocardial change in doxorubicin-induced dilated cardiomyopathy determined using dual-energy computed tomography (CT) were similar to characterization by extracellular volume fraction (ECV) using cardiac magnetic resonance (CMR) T1-mapping and collagen volume fraction (CVF) measured using histology., Background: Anthracycline chemoagents are effective against a wide range of malignant conditions. However, cardiotoxicity is a well-known adverse effect of these drugs. Dual-energy CT could be as useful as magnetic resonance (MR) to evaluate myocardial change in anthracycline-induced cardiotoxicity., Methods: A dilated cardiomyopathy rabbit model was generated by injecting 11 adult New Zealand rabbits with 1.0 mg/kg of doxorubicin twice weekly for 16 weeks. Contrast-enhanced dual-energy CT and pre-contrast and post-contrast T1-mapping CMR using a prototype modified Look-Locker inversion recovery on a clinical 3-T scanner were performed on 15 rabbits, including 4 control animals, to calculate ECV at baseline, and at 6, 12, and 16 weeks after doxorubicin administration., Results: The mean ECV values (%) on CT and CMR at 6, 12, and 16 weeks after modeling were significantly higher than those measured at baseline (CT ECV: 35.3%, 41.9%, 42.1% vs. 28.5%; MR ECV: 32.6%, 35.8%, 41.3% vs. 28.8%, respectively; all p < 0.001). CT ECV and MR ECV values were well correlated (r = 0.888; p < 0.001). Both were well correlated with CVF on histology (CT ECV vs. CVF, r = 0.925, p < 0.001 and MR ECV vs. CVF, r = 0.961, p < 0.001, respectively)., Conclusions: Dual-energy CT ECV correlated well with CMR and histology. Dual-energy CT is useful for characterizing doxorubicin-induced cardiomyopathy by measuring ECV fraction; however, further technical improvements are desirable to lower motion artifact and improve image quality of the iodine map., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To assess whether multi-echo Dixon magnetic resonance (MR) imaging with simultaneous T2* estimation and correction yields more accurate fat-signal fraction (FF) measurement of the lumbar paravertebral muscles, in comparison with non-T2*-corrected two-echo Dixon or T2*-corrected three-echo Dixon, using the FF measurements from single-voxel MR spectroscopy as the reference standard., Materials and Methods: Sixty patients with low back pain underwent MR imaging with a 1.5T scanner. FF mapping images automatically obtained using T2*-corrected Dixon technique with two (non-T2*-corrected), three, and six echoes, were compared with images from single-voxel MR spectroscopy at the paravertebral muscles on levels L4 through L5. FFs were measured directly by two radiologists, who independently drew the region of interest on the mapping images from the three sequences., Results: A total of 117 spectroscopic measurements were performed either bilaterally (57 of 60 subjects) or unilaterally (3 of 60 subjects). The mean spectroscopic FF was 14.3 ± 11.7% (range, 1.9-63.7%). Interobserver agreement was excellent between the two radiologists. Lin's concordance correlation between the spectroscopic findings and all the imaging-based FFs were statistically significant (p < 0.001). FFs obtained from the T2*-corrected six-echo Dixon sequences showed a significantly better concordance with the spectroscopic data, with its concordance correlation coefficient being 0.99 and 0.98 (p < 0.001), as compared with two- or three-echo methods., Conclusion: T2*-corrected six-echo Dixon sequence would be a better option than two- or three-echo methods for noninvasive quantification of lumbar muscle fat quantification.

Objective: To assess the feasibility of T2*-corrected fat-signal fraction (FF) map by using the three-echo volume interpolated breath-hold gradient echo (VIBE) Dixon sequence to differentiate between malignant marrow-replacing lesions and benign red marrow deposition of vertebrae., Materials and Methods: We assessed 32 lesions from 32 patients who underwent magnetic resonance imaging after being referred for assessment of a known or possible vertebral marrow abnormality. The lesions were divided into 21 malignant marrow-replacing lesions and 11 benign red marrow depositions. Three sequences for the parameter measurements were obtained by using a 1.5-T MR imaging scanner as follows: three-echo VIBE Dixon sequence for FF; conventional T1-weighted imaging for the lesion-disc ratio (LDR); pre- and post-gadolinium enhanced fat-suppressed T1-weighted images for the contrast-enhancement ratio (CER). A region of interest was drawn for each lesion for parameter measurements. The areas under the curve (AUC) of the parameters and their sensitivities and specificities at the most ideal cutoff values from receiver operating characteristic curve analysis were obtained. AUC, sensitivity, and specificity were respectively compared between FF and CER., Results: The AUCs of FF, LDR, and CER were 0.96, 0.80, and 0.72, respectively. In the comparison of diagnostic performance between the FF and CER, the FF showed a significantly larger AUC as compared to the CER (p = 0.030), although the difference of sensitivity (p = 0.157) and specificity (p = 0.157) were not significant., Conclusion: Fat-signal fraction measurement using T2*-corrected three-echo VIBE Dixon sequence is feasible and has a more accurate diagnostic performance, than the CER, in distinguishing benign red marrow deposition from malignant bone marrow-replacing lesions.

The diagnosis of myocarditis can be challenging given that symptoms, clinical exam findings, electrocardiogram results, biomarkers, and echocardiogram results are often non-specific. Endocardial biopsy is an established method for diagnosing myocarditis, but carries the risk of complications and false negative results. Cardiac magnetic resonance imaging (MRI) has become the primary non-invasive imaging tool in patients with suspected myocarditis. Myocarditis can be diagnosed by using three tissue markers including edema, hyperemia/capillary leak, and necrosis/fibrosis. The interpretation of cardiac MR findings can be confusing, especially when the myocardium is diffusely involved. Using T1 and T2 maps, the diagnosis of myocarditis can be made even in cases of global myocarditis with the help of quantitative analysis. We herein describe a case of acute global myocarditis which was diagnosed by using quantitative T1 and T2 mapping.

Background: Post-contrast T1 mapping by modified Look-Locker inversion recovery (MOLLI) sequence has been introduced as a promising means to assess an expansion of the extra-cellular space. However, T1 value in the myocardium can be affected by scanning time after bolus contrast injection. In this study, we investigated the changes of the T1 values according to multiple slicing over scanning time at 15 minutes after contrast injection and usefulness of blood T1 correction., Methods: Eighteen reperfused acute myocardial infarction (AMI) patients, 13 cardiomyopathy patients and 8 healthy volunteers underwent cardiovascular magnetic resonance with 15 minute-post contrast MOLLI to generate T1 maps. In 10 cardiomyopathy cases, pre- and post-contrast MOLLI techniques were performed to generate extracellular volume fraction (Ve). Six slices of T1 maps according to the left ventricular (LV) short axis, from apex to base, were consecutively obtained. Each T1 value was measured in the whole myocardium, infarcted myocardium, non-infarcted myocardium and LV blood cavity., Results: The mean T1 value of infarcted myocardium was significantly lower than that of non-infarcted myocardium (425.4 ± 68.1 ms vs. 540.5 ± 88.0 ms, respectively, p < 0.001). T1 values of non-infarcted myocardium increased significantly from apex to base (from 523.1 ± 99.5 ms to 561.1 ± 81.1 ms, p = 0.001), and were accompanied by a similar increase in blood T1 value in LV cavity (from 442.1 ± 120.7 ms to 456.8 ± 97.5 ms, p < 0.001) over time. This phenomenon was applied to both left anterior descending (LAD) territory (from 545.1 ± 74.5 ms to 575.7 ± 84.0 ms, p < 0.001) and non-LAD territory AMI cases (from 501.2 ± 124.5 ms to 549.5 ± 81.3 ms, p < 0.001). It was similarly applied to cardiomyopathy patients and healthy volunteers. After the myocardial T1 values, however, were adjusted by the blood T1 values, they were consistent throughout the slices from apex to base (from 1.17 ± 0.18 to 1.25 ± 0.13, p > 0.05). The Ve did not show significant differences from apical to basal slices., Conclusion: Post-contrast myocardial T1 corrected by blood T1 or Ve, provide more stable measurement of degree of fibrosis in non-infarcted myocardium in short- axis multiple slicing.