Differential Subsampling With Cartesian Ordering Research Articles

Application of Differential Subsampling with Cartesian Ordering in Evaluating Left Ovarian Venous Reflux for Pretreatment Planning for Pelvic Venous Disorders.

The diagnosis of a common cause of chronic pelvic pain can be made by visualizing reflux in the ovarian veins. Fluoroscopic venography is the gold standard for diagnosing ovarian vein reflux, but it is an invasive technique that exposes patients to ionizing radiation. MRI, with its lack of ionizing radiation and capability of high-temporal and spatial-resolution vascular imaging, has the potential to provide similar diagnostic information. This retrospective report describes and assesses the utility of a dynamic contrast-enhanced MRI technique based on Differential Subsampling with Cartesian Ordering (DISCO)-MRI in 30 patients with chronic pelvic pain. Among the 14 patients who underwent both DISCO-MRI and fluoroscopic venograms, 11 (78.6%) exhibited concordant results, while 3 patients (21.4%) had discordant findings. These results suggest the potential of multiphasic contrast-enhanced DISCO-MRI as a non-invasive diagnostic tool for evaluating chronic pelvic pain.

Multiparametric MRI model with synthetic MRI, DWI multi-quantitative parameters, and differential sub-sampling with cartesian ordering enables BI-RADS 4 lesions diagnosis with high accuracy.

To assess the feasibility and diagnostic performances of synthetic magnetic resonance imaging (SyMRI) combined with diffusion-weighted imaging (DWI) and differential subsampling with cartesian ordering (DISCO) in breast imaging reporting and data system (BI-RADS) 4 lesions. A total of 98 BI-RADS 4 patients, including 68 cases assigned to a malignant group and 33 cases assigned to a benign group, were prospectively enrolled, and their MRI and clinical information were collected. Two physicians jointly analyzed the characteristics of conventional MRI. T1, T2, proton density (PD), and ADC values were obtained from three different regions of interest (ROIs). Logistic regression analyses were used to select features and build models, and a nomogram was constructed with the best model. Using the ROI delineation method at the most obvious enhancement to measure the ADC value revealed the best diagnostic performance in diagnosing BI-RADS type 4 mass lesions. The diagnostic efficiency of the maximum level drawing method of the quantitative relaxation model was better than that of the whole drawing method and the most obvious enhancement method. The best relaxation model (model A) was composed of two parameters: T2stand and ΔT1%stand (AUC=0.887), and the BI-RADS model (model B) was constructed by two MRI features of edge and TIC curve (AUC=0.793). Using the quantitative parameters of SyMRI and DWI of the best ROC method combined with DISCO enhanced MRI features to establish a joint diagnostic model (model C: edge, TIC curve type, ADClocal, T2stand, ΔT1%stand) showed the best diagnostic efficiency (AUC=0.953). The nomogram also had calibration curves with good overlap. The combined diagnosis model of SyMRI and DWI quantitative parameters combined with DISCO can improve the diagnostic efficiency of BI-RADS 4 types of mass lesions. Also, the line diagram based on this model can be used as an auxiliary diagnostic tool.

Technical feasibility of uro-dynamic MRI study of voiding biomechanics: a pilot study.

Dynamic volumetric MRI was used to non-invasively assess voiding biomechanics in a healthy male volunteer. Using 3D Differential Subsampling with Cartesian Ordering (DISCO) Flex acquisition sequence, volumetric bladder images were obtained throughout the voiding effort. These were subsequently segmented using MIMICS. Segmented anatomical volumes were used to quantify total voided volume, post-void residual, volumetric displacement of urine over time, bladder neck angle, sphericity index, and prostatic urethral angle through the voiding effort. Bladder sphericity index correlated positively with flow rate. The greatest degree of bladder neck funneling correlated with the maximum urine flow rate. There was straightening of the prostatic urethral angle during voiding that also correlated positively with urine flow. This pilot study confirms the potential of dynamic MRI to provide non-invasive assessment of lower urinary tract anatomy and biomechanics during voiding.

The value of DISCO and MUSE-DWI combined with prostate specific antigen density in the diagnosis and risk stratification of prostate cancer

Objective: To explore the value of differential subsampling with cartesian ordering (DISCO) and multiplexed sensitivity-encoding diffusion weighted-imaging (MUSE-DWI) combined with prostate specific antigen density (PSAD) in the diagnosis and risk stratification of prostate cancer (PCa). Methods: The data of 183 patients [aged from 48 to 86 (68±8) years] with prostate diseases in the General Hospital of Ningxia Medical University from July 2020 to August 2021 were retrospectively collected. Those patients were divided into non-PCa group (n=115) and PCa group (n=68) based on the disease condition. According to the risk degree, PCa group was subdivided into low risk PCa group (n=14) and medium-to-high risk PCa group (n=54). The differences of volume transfer constant (Ktrans), rate constant (Kep), extracellular volume fraction (Ve), apparent diffusion coefficient (ADC) and PSAD between groups were analyzed. Receiver operating characteristic (ROC) curves analysis were conducted for evaluating the diagnostic efficacy of quantitative parameters and PSAD in distinguishing non-PCa and PCa, low-risk PCa and medium-high risk PCa. Multivariate logistic regression model was used for screening out the predictors, which was statistically significant differences between non-PCa group and PCa group, for PCa prediction. Results: Ktrans, Kep, Ve and PSAD of PCa group all were higher than those of non-PCa group, and ADC value was lower than that of non-PCa group, and the differences all were statistically significant (all P<0.001). Ktrans, Kep and PSAD of medium-to-high risk PCa group all were higher than those of low risk PCa group, and ADC value was lower than that of low risk PCa group, and the differences were all statistically significant (all P<0.001). When distinguishing non-PCa from PCa, the area under ROC curve (AUC) of the combined model (Ktrans+Kep+Ve+ADC+PSAD) was higher than that of any single index [0.958 (95%CI: 0.918-0.982) vs 0.881 (95%CI: 0.825-0.924), 0.836 (95%CI: 0.775-0.887), 0.672 (95%CI: 0.599-0.740), 0.940(95%CI: 0.895-0.969), 0.816(95%CI:0.752-0.869), all P<0.05]. When distinguishing low-risk PCa and medium-to-high risk PCa, the AUC of the combined model (Ktrans+Kep+ADC+PSAD) were higher than those of Ktrans, Kep and PSAD[0.933 (95%CI: 0.845-0.979) vs 0.846 (95%CI:0.738-0.922), 0.782 (95%CI:0.665-0.873), 0.84 8(95%CI: 0.740-0.923), all P<0.05]. The multivariate logistic regression analysis showed that Ktrans (OR=1.005, 95%CI:1.001-1.010) and ADC values (OR=0.992, 95%CI:0.989-0.995) were predictors of PCa (P<0.05). Conclusions: DISCO and MUSE-DWI combined with PSAD can distinguish benign and malignant prostate lesions. Ktrans and ADC values were predictors of PCa; Ktrans, Kep, ADC values and PSAD are helpful in predicting the biological behavior of PCa.

Combination of ultrafast dynamic contrast-enhanced MRI-based radiomics and artificial neural network in assessing BI-RADS 4 breast lesions: Potential to avoid unnecessary biopsies.

To investigate whether combining radiomics extracted from ultrafast dynamic contrast-enhanced MRI (DCE-MRI) with an artificial neural network enables differentiation of MR BI-RADS 4 breast lesions and thereby avoids false-positive biopsies. This retrospective study consecutively included patients with MR BI-RADS 4 lesions. The ultrafast imaging was performed using Differential sub-sampling with cartesian ordering (DISCO) technique and the tenth and fifteenth postcontrast DISCO images (DISCO-10 and DISCO-15) were selected for further analysis. An experienced radiologist used freely available software (FAE) to perform radiomics extraction. After principal component analysis (PCA), a multilayer perceptron artificial neural network (ANN) to distinguish between malignant and benign lesions was developed and tested using a random allocation approach. ROC analysis was performed to evaluate the diagnostic performance. 173 patients (mean age 43.1 years, range 18-69 years) with 182 lesions (95 benign, 87 malignant) were included. Three types of independent principal components were obtained from the radiomics based on DISCO-10, DISCO-15, and their combination, respectively. In the testing dataset, ANN models showed excellent diagnostic performance with AUC values of 0.915-0.956. Applying the high-sensitivity cutoffs identified in the training dataset demonstrated the potential to reduce the number of unnecessary biopsies by 63.33%-83.33% at the price of one false-negative diagnosis within the testing dataset. The ultrafast DCE-MRI radiomics-based machine learning model could classify MR BI-RADS category 4 lesions into benign or malignant, highlighting its potential for future application as a new tool for clinical diagnosis.

Customizing Anterolateral Thigh Flap With Magnetic Resonance Angiography Differential Subsampling With Cartesian Ordering Imaging for Individualized Reconstruction of Extremity Defects

IntroductionMagnetic resonance angiography (MRA) with the differential subsampling with cartesian ordering (DISCO) imaging technique is rarely used in anterolateral thigh (ALT) flap. In our series, MRA DISCO imaging technique is used as a tool to customize ALT flaps. The aim of this study was to report the accuracy of cutaneous perforators identified by the MRA DISCO imaging. MethodsNineteen patients underwent the MRA DISCO imaging for perforator mapping before the ALT flap transfer. A total of 38 ALT regions were studied on the MRA DISCO images. Flap thinning was performed under the guidance of MRA DISCO imaging. ResultsThe lateral circumflex femoral artery (LCFA) most commonly stems from the deep femoral artery (84.2%), followed by the common femoral artery (15.8%). The average number of perforator vessels per LCFA was 10.2 ± 1.7. The distinct oblique branch was observed in 16 out of the 38 ALT regions (42.1%). Among the 19 ALT flaps harvested, 5 were septocutaneous perforator flaps and 14 musculocutaneous perforator flaps. Ten were harvested based on the descending branch, and 3 used the oblique branch as the flap vascular pedicle. In addition, the displayed course and types of perforator vessels on the DISCO images of the 18 skin flaps were consistent with the intraoperative findings, with an accuracy of 94.7%. ConclusionsThe state of the cutaneous perforators of LCFA can be identified on the MRA DISCO images. The 3D-CE-MRA DISCO imaging is a practical method, which can ameliorate the design and customization of ALT flap for an individualized reconstruction.

Differential subsampling with cartesian ordering: A high spatial-temporal resolution dixon imaging sequence for assessment of dural arteriovenous fistula.

To evaluate the accuracy of differential subsampling with cartesian ordering (DISCO) in comparison to time of flight (TOF) in detecting dural arteriovenous fistulas (DAVF), cerebral venous thrombosis (CVT) and hemodynamics. Sixty-two cases (24 female; aged 14-75; mean age, 51.3 years) were included in our study, with 42 positive and 20 negative cases via Digital Subtraction Angiography (DSA). Two neuroradiologists independently evaluated the DISCO and TOF. The sensitivity, specificity, and accuracy of the DISCO and TOF-MRA were individually calculated using DSA as the gold standard. Inter-observer reliability was assessed by using a weighted Cohen's kappa (κ) test; P < 0.05 was set as the threshold for statistical significance. Diagnostic sensitivities of DISCO and TOF for DAVF were 92.86 and 64.29%; specificities were 95.0% and 95.0%; while accuracies were 93.55 and 74.19% respectively. For detected CVT, sensitivities of DISCO and TOF were 100 and 92.31%; specificities were 96.55 and 93.10%; with accuracies 97.62 and 92.86% respectively. In hemodynamic analysis, sensitivity of DISCO for reflux was 95.45%; with a specificity of 95.0%; and accuracy 95.24%. The inter-observer kappa values were 0.857 for DISCO (P < 0.001). DISCO showed a high degree of sensitivity and specificity, suggesting its effectiveness in detecting DAVF with or without CVT. Intracranial hemodynamics can be identified using DISCO in DAVF patients, providing accurate evaluation of cerebral blood flow dynamics during the pre-treatment phase.

Differential Subsampling with Cartesian Ordering-MRA for Classifying Residual Treated Aneurysms.

Differential Subsampling with Cartesian Ordering (DISCO), an ultrafast high-spatial-resolution head MRA, has been introduced. We aimed to determine the diagnostic performance of DISCO-MRA in grading residual aneurysm in comparison with TOF-MRA in patients with treated intracranial aneurysms. Patients with endovascular treatment and having undergone DISCO-MRA, TOF-MRA, and DSA were included for review. The voxel size and acquisition time were 0.75 × 0.75 × 1 mm3/6 seconds for DISCO-MRA and 0.6 × 0.6 × 1 mm3/6 minutes for TOF-MRA. Residual aneurysms were determined using the Modified Raymond-Roy Classification on TOF-MRA and DISCO-MRA by 2 neuroradiologists independently and were compared against DSA as the reference standard. Statistical analysis was performed using the κ statistic and the χ2 test. Sixty-eight treated intracranial aneurysms were included. The intermodality agreement was κ = 0.82 (95% CI, 0.67-0.97) between DISCO and DSA and 0.44 (95% CI, 0.28-0.61) between TOF and DSA. Modified Raymond-Roy Classification scores matched DSA scores in 60/68 cases (88%; χ2 = 144.4, P < .001 for DISCO and 46/68 cases (68%; χ2 = 65.0, P < .001) for TOF. The diagnostic accuracy for the detection of aneurysm remnants was higher for DISCO (0.96; 95% CI, 0.88-0.99) than for TOF (0.79; 95% CI, 0.68-0.88). In patients with endovascularly treated intracranial aneurysms, DISCO-MRA provides superior diagnostic performance in comparison with TOF-MRA in delineating residual aneurysms in a fraction of the time.

Differential Subsampling with Cartesian Ordering Contrast-Enhanced Magnetic Resonance Angiography for the Preoperative Assessment of Anterolateral Thigh Flap.

ObjectiveTo investigate the clinical application of differential subsampling with Cartesian ordering (DISCO) contrast-enhanced (CE) magnetic resonance angiography for anterolateral thigh (ALT) flap transplantation, using operative findings as a reference.Materials and MethodsThirty patients (21 males and nine females; mean age ± standard deviation, 45.5 ± 15.6 years) who were scheduled to undergo reconstruction with ALT flaps between June 2020 and June 2021 were included in the prospective study. Before ALT flap transplantation, patients were scanned using CE-DISCO imaging. All acquired DISCO images of the 60 lower limbs (both sides from each patient) were analyzed using maximum intensity projection and volume rendering methods. Two experienced radiologists were employed to examine the patterns of the lateral circumflex femoral artery (LCFA), its branches, and perforators and their skin termini, which were compared with the operative findings.ResultsUsing CE-DISCO, the patterns of the LCFA and its branches were clearly identified in all patients. Four different origins of the LCFA were found among the 60 blood vessels: type I (44/60, 73.3%), type II (6/60, 10.0%), type III (8/60, 13.3%), and type IV (2/60, 3.3%). Owing to a lack of perforators entering the skin, two patients did not undergo ALT flap transplantation. For the remaining 28 patients, the ALT flaps in 26 patients were successfully operated without flap re-selection during the operation, while the remaining two patients underwent other surgical procedures due to the thin diameter of the perforator or injury of the perforator during the operation. The success rate of flap transplantation was 92.8% (26/28). All transplanted flaps exhibited good blood supply and achieved primary healing without infection or delayed healing.ConclusionCE-DISCO imaging can be an effective method for preoperative perforator imaging before ALT flap transplantation.

Transient Respiratory-motion Artifact and Scan Timing during the Arterial Phase of Gadoxetate Disodium-enhanced MR Imaging: The Benefit of Shortened Acquisition and Multiple Arterial Phase Acquisition.

Purpose:To investigate whether shortened acquisition or multiple arterial phase acquisition improves image quality of the arterial phase compared with conventional protocol.Methods:This retrospective study was approved by the relevant Institutional Review Board. A total of 615 consecutive patients who underwent gadoxetate disodium-enhanced MRI including one of the following three sequences in three different periods were included: (i) conventional liver acquisition with volume acceleration (LAVA) (between October 2014 and January 2015, n = 149), (ii) Turbo-LAVA (between March and August 2016, n = 216), and (iii) differential sub-sampling with Cartesian ordering (DISCO) (between January and September 2015, n = 250). We monitored the respiratory bellows waveform during breath holding for each patient and recorded breath-hold fidelity of the patients. Two radiologists independently evaluated the degree of respiratory artifact and scan timing on the arterial phase and compared them between the three protocols (i.e., conventional LAVA, Turbo-LAVA, and DISCO), with conventional LAVA as control.Results:The ratio of patients with breath-hold failure was not significantly different among the three protocols (P = 0.6340 and 0.1085). Respiratory artifact was significantly lower in DISCO than in conventional LAVA (P = 0.0424), while there was no significant difference between Turbo-LAVA and conventional LAVA (P = 0.2593). The ratio of adequate scan timing and diagnosable image defined as no or mild artifact and adequate scan timing were higher in DISCO than in conventional LAVA (P = 0.0025 and 0.0019), while there was no significant difference between Turbo-LAVA and conventional LAVA (P = 0.0780 and 0.0657).Conclusion:Compared with conventional protocol, multiple arterial phase acquisition (DISCO) obtained a higher number of diagnosable images by reducing respiratory motion artifact and optimizing the scan timing of arterial phase.

Improved Display of Hepatic Arterial Anatomy Using Differential Subsampling With Cartesian Ordering (DISCO) With Gadoxetic Acid-Enhanced MRI: Comparison With Single Arterial Phase MRI and Computed Tomographic Angiography.

In clinical practice arterial anatomy evaluation is often determined using computed tomographic angiography (CTA); the effect of enhanced MRI has been neglected. To evaluate whether multiple arterial phase (MAP) images from patients who underwent differential subsampling with Cartesian ordering (DISCO) acquisition would improve the hepatic arterial display compared with single arterial phase (SAP) and CTA. A prospective, randomized trial. In all, 130 patients (mean age, 55.81 ± 9.43 years; range, 35-78 years) including 89 men and 41 women. 3.0T, DISCO, liver acquisition with volume acceleration-flexible (LAVA-Flex), CTA. A simple randomization was conducted and the study was subdivided into study part I (DISCO vs. SAP) and study part II (DISCO vs. CTA). Ten hepatic arterial segments were independently evaluated by three readers in the axial plane and the quality of hepatic arterial display was assessed using a four-point scale. Kendall's W-test, χ2 test, Mann-Whitney U-test, and Kruskal-Wallis one-way analysis of variance (ANOVA) test. Excellent interobserver agreement was obtained for hepatic arterial display (all Kendall's W values >0.80). For study part I, the mean arterial display scores for the common hepatic artery (CHA), proper hepatic artery (PHA), left hepatic artery (LHA), right hepatic artery (RHA), left gastric artery (LGA), and gastroduodenal artery (GDA) obtained with DISCO were higher than that obtained with SAP imaging (all P < 0.01). For study part II, comparable image quality for CHA (P = 0.798), PHA (P = 0.440), LHA (P = 0.211), RHA (P = 0.775) LGA (P = 0.468), and GDA (P = 0.801) was obtained with DISCO and CTA. The use of MAP acquisition with DISCO is superior to the use of SAP in hepatic arterial display and compares favorably with CTA; in the future, DISCO possibly can replace the latter ionization-related method to provide a more comprehensive evaluation of the liver arterial vessels. 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1766-1776.

Multi?arterial phase MRI of hepatic vessels using gadoxetic acid: intraindividual comparison of CTA

Objective To investigate the value of multi-arterial phase differential sub-sampling with cartesian ordering (DISCO) technique in the evaluation of hepatic vascular anatomy with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Methods Forty-eight patients with suspected hepatic malignancy were prospectively enrolled and underwent both of Gd-EOB-DTPA enhanced DISCO MRI and CTA within two weeks. The hepatic arterial anatomy of two examination methods were evaluated by four-point scoring method. The arterial scores between DISCO and CTA images were compared by Wilcoxon test. The difference among multiple arterial scores of DISCO and CTA were compared by Kruskal-Wallis H test respectively. Results There was no difference of arterial scores in celiac artery, common hepatic artery, proper hepatic artery, left hepatic artery, right hepatic artery, first branch of right hepatic artery, splenic artery, left gastric artery and gastroduodenal artery between DISCO and CTA (P>0.05), but the arterial score of first branch of left hepatic artery [2 (2,2)] was lower than that of CTA [2 (2,3)] (Z=-3.138,P=0.002). In the multiple comparison among different arteries, there were differences between PHA and LAH (P 0.05). Conclusion The DISCO sequence with Gd-EOB-DTPA enhancement MRI can supply comparable image quality to CTA in hepatic artery and its main branches display, which has no ionizing radiation and can also provide more diagnostic information for clinic. Key words: Liver; Magnetic resonance imaging; Gadoxetate acid disodium

Evaluation of multiple-arterial-phase aquisition and image quality in gadoxetate acid disodium enhanced liver MRI using differential sub-sampling with cartesian ordering technique: a comparative study with single arterial phase

Objective To investigate the application value of multiple-arterial-phase imaging technique with differential sub-sampling with cartesian ordering (DISCO) in the gadoxetate acid disodium enhanced liver MRI. Methods From September 2017 to March 2018, 56 patients with suspected malignant focal liver disease diagnosed with ultrasound or CT in West China Hospital of Sichuan University were enrolled prospectively, and underwent preoperative enhanced MRI with gadoxetate acid disodium. Patients were divided into 2 groups by random-number table method. Twenty nine patients in group A underwent liver multiple-arterial-phase imaging with DISCO. Twenty seven patients in group B underwent single-arterial-phase imaging with liver acquisition with volume acceleration-flex (LAVA-Flex). The display rate of late-arterial-phase and respiratory motion artifacts of dynamic enhancement images were evaluated. The categorical variables was compared by Chi-square test. The respiratory motion artifacts between the single-arterial-phase and multiple-arterial-phases were compared by Mann-Whitney U test. The artifact scores among the various phases of the multi-arterial phase were compared by Kruskal-Wallis H. Results Compared to LAVA-Flex [74.1%(20/27)], a higher display rate of late-arterial phase [96.6%(28/29)] was found in DISCO (Group A), and the difference was statistically significant (χ2=5.770, P=0.016). In the evaluation of respiratory motion artifacts, the motion artifacts of the late-arterial images obtained by LAVA-Flex [3(3,4)] were more severe than the DISCO [2(2,3)], and the difference was statistically significant (Z=-3.250, P 0.05). Conclusion Compared with single-arterial-phase imaging, multiple-arterial-phases with DISCO using gadoxetate acid disodium can improve the capture rate of late arterial phase and reduce motion artifacts. Key words: Liver; Late-arterial phase; Magnetic resonance imaging; Gadoxetate acid disodium

Differential Subsampling with Cartesian Ordering for Ultrafast High-Resolution MRA in the Assessment of Intracranial Aneurysms.

We aimed to evaluate the feasibility of an ultrafast whole head contrast-enhanced MRA (CE-MRA) in morphometric assessment of intracranial aneurysms in comparison to routinely used time-of-flight (TOF)-MRA. In this prospective single institutional study, patients with known untreated intracranial aneurysm underwent MRA. Routine multislab TOF-MRA was obtained with a 3D voxel sizes of .6 × .6 × 1 (6-minute acquisition time). CE-MRA of whole head was obtained using Differential Subsampling with Cartesian Ordering (DISCO) and 2D Auto-calibrating Reconstruction for Cartesian imaging with a 3D voxel-sizes of .75 × .75 × 1 mm3 during a 6-second temporal resolution. Morphometric features of intracranial aneurysms, including size, aneurysm sac morphology, and the presence of intraluminal thrombosis, were assessed on both techniques. Statistical analysis was performed using a combination of Kappa test, Bland-Altman, and correlation coefficient analysis. A total of 34 aneurysms in 28 patients were included. Aneurysm size measurements (mean ± SD) were similar between DISCO-MRA (4.1 ± 2.3 mm) and TOF-MRA (4.3 ± 2.8 mm) (P = .27). Bland-Altman analysis showed a mean difference of .4 mm and there was excellent correlation r = .91 (95% CI: .87-.96). In six aneurysms (17.6%), TOF-MRA was nonconfidant to exclude intraluminal thrombosis. In seven aneurysms (20%), TOF-MRA was unable or nonconfidant in depicting aneurysm sac morphology. Described ultrafast high spatial-resolution MRA is superior to routinely used TOF-MRA in assessment of morphometric features of intracranial aneurysms, such as intraluminal thrombosis and aneurysm morphology, and is obtained in a fraction of the time (6 seconds).

Gadoxetate acid disodium-enhanced MRI: Multiple arterial phases using differential sub-sampling with cartesian ordering (DISCO) may achieve more optimal late arterial phases than the single arterial phase imaging

BackgroundTo prospectively determine whether the use of a multiple arterial phase imaging (DISCO) improve the capturing rate of late arterial phase with less motion artifact than single arterial phase obtained with gadoxetate acid disodium. Materials and methodsFrom 06/2017 to 10/2018, prospectively acquired data of 132 patients who underwent either single (n = 67) or multiple arterial phase (n = 65) gadoxetate acid-enhanced MR imaging were analyzed. Two readers independently assessed arterial phase timing and the degree of motion artifact using a five-point scale. The kappa test was used to determine the agreement between the two readers, χ2 or fisher exact test were used for the categorical variables and Student t-test or Mann-Whitney U test were used for the comparison of the motion artifacts. ResultsGood to perfect inter-observer agreement was obtained for the arterial phase timing and degree of motion artifact (all kappa value >0.70). Optimal timing of arterial phase was observed in 95.4% (62/65) of multiple arterial phase compared with 73.1% (49/67) of single arterial phase (χ2 = 12.209, p < 0.001). Motion artifact score of the late arterial phase images measured using single arterial phase acquisition (3.22 ± 0.68) was significantly higher than the multiple arterial phase (2.42 ± 0.74) group (t = 5.921, p < 0.001). For the multiple arterial phase comparison, motion artifact score of the 2nd, 3rd and 4th phases were also significant reduced compared with 1st, 5th and 6th phases (all p < 0.05). ConclusionThe use of multiple arterial phase acquisition with gadoxetate acid disodium can improve the capturing rate of well-timed late arterial phase with less motion artifact.

3 T MR perfusion of solid pancreatic lesions using dynamic contrast-enhanced DISCO sequence: Usefulness of qualitative and quantitative analyses in a pilot study

PurposeTo assess the usefulness of qualitative and quantitative analyses of pancreatic focal diseases by using the dynamic contrast-enhanced Differential Subsampling with Cartesian Ordering (DISCO) sequence at 3 T MR device. Materials and methodsTen patients without pancreatic diseases and twenty-five patients with pathologically confirmed pancreatic focal disease (ductal adenocarcinoma, n = 14; endocrine tumour, n = 8; focal chronic pancreatitis, n = 3), underwent MRI by 3 T-device. Multiphasic contrast-enhanced MR perfusion, consisting of a 3D axial navigator, based free-breathing T1-weighted DISCO sequence, was repeated for 5 min. A dose of 0.1 mL/kg of Gadobutrolo with a 20 mL saline flush was injected at a flow rate of 5 mL/s. Perfusion MRI were processed using a dedicated software package (GeniQ; GE Healthcare), obtaining both a time-signal-intensity curve (TSIC) and perfusion maps for each healthy pancreatic parenchyma and focal disease. The TSIC were grouped into four types according to their shapes and the MR perfusion parameters (Ktrans, Kep, Ve, IAUGC) were calculated.The one-way analysis of variance and the Student's t-test were used to correlate the quantitative and qualitative parameters with the tissue histology. ResultsAll 10 patients with healthy pancreas presented a TSIC-type 1; TSIC-type 2 was observed in all 14 ductal adenocarcinomas and in one neuroendocrine tumour; TSIC-type 3 was recognized in the remaining 7 neuroendocrine neoplasms; TSIC-type 4 was identified in all 3 focal chronic pancreatitis. All perfusion parameters were significantly different (p < 0.0001) for each type of lesion. Furthermore, Ve was also very useful to discriminate between normal and pathological tissues (p = 0.0005). ConclusionQualitative and quantitative analyses of contrast-enhanced 3 T MR perfusion, using the dynamic contrast-enhanced DISCO sequence, could be considered an interesting tool to improve the diagnosis of focal pancreatic diseases, of solid lesions in particular. Further investigations with prospective larger sample studies are required to confirm these preliminary results.

MR lymphography for sentinel lymph node detection in patients with oral cavity cancer: Preliminary clinical study.

The purpose of this study was to evaluate the feasibility of MR lymphography with interstitial injection of a gadolinium-based contrast agent for identifying sentinel lymph nodes in patients with oral cavity cancer and clinically negative neck. Pretreatment MR lymphography with a differential subsampling with cartesian ordering (DISCO) sequence was performed in 26 patients with resectable oral cavity cancer and clinically negative neck, after peritumoral injection of 1-mL diluted gadobutrol. The accuracy of sentinel lymph node identification by MR lymphography was assessed and compared with the final histopathological results. The MR lymphography consistently visualized the 44 sentinel lymph nodes in all 26 patients. In all but 1 patient with pathologically positive neck, assumed sentinel lymph nodes revealed metastatic involvement. Pretreatment MR lymphography is a safe and feasible imaging technique that can help clinicians identify sentinel lymph nodes with a high risk of occult metastases in patients with oral cavity cancer, enabling focused preoperative biopsy in these high-risk patients.

Ring-Like Enhancement of Hepatocellular Carcinoma in Gadoxetic Acid–Enhanced Multiphasic Hepatic Arterial Phase Imaging With Differential Subsampling With Cartesian Ordering

The aim of this study was to evaluate the efficacy of multiphasic hepatic arterial phase (HAP) imaging using DISCO (differential subsampling with Cartesian ordering) in increasing the confidence of diagnosis of hepatocellular carcinoma (HCC). This retrospective study was approved by the institutional review board, and the requirement for informed patient consent was waived. Consecutive patients (from 2 study periods) with malignant liver nodules were examined by gadoxetic acid-enhanced magnetic resonance imaging using either multiphasic (6 phases; n = 135) or single (n = 230) HAP imaging, which revealed 519 liver nodules other than benign ones (HCC, 497; cholangiocarcinoma, 11; metastases, 10; and malignant lymphoma, 1). All nodules were scored in accordance with the Liver Imaging Reporting and Data System (LI-RADS v2014), with or without consideration of ring-like enhancement in multiphasic HAP images as a major feature. In the multiphasic HAP group, 178 of 191 HCCs were scored as LR-3 to LR-5 (3 [1.69%], 85 [47.8%], and 90 [50.6%], respectively). Upon considering ring-like enhancement in multiphasic HAP images as a major feature, 5 more HCCs were scored as LR-5 (95 [53.4%]), which was a significantly more confident diagnosis than that with single HAP images (295 of 306 HCCs scored as LR-3 to LR-5: 13 [4.41%], 147 [49.8%], and 135 [45.8%], respectively; P = 0.0296). There was no significant difference in false-positive or false-negative diagnoses between the multiphasic and single HAP groups (P = 0.8400 and 0.1043, respectively). Multiphasic HAP imaging can improve the confidence of diagnosis of HCCs in gadoxetic acid-enhanced magnetic resonance imaging.

Combined parenchymal and vascular imaging: High spatiotemporal resolution arterial evaluation of hepatocellular carcinoma.

To assess the ability of high-resolution arterial phase imaging of hepatocellular carcinoma (HCC) to provide combined vascular characterization and parenchymal evaluation. Thirty-eight consecutive studies in cirrhotic patients with HCC scanned with a view-shared 2-point-Dixon-based Differential Subsampling with Cartesian Ordering (DISCO) sequence were analyzed. Lesion contrast relative to precontrast and adjacent parenchyma was evaluated and compared using a Fisher's exact test. Visibility of hepatic arteries and tumor feeding vessels were graded on a 5-point scale. Catheter angiography was used as a reference standard for arterial anatomy. The high spatiotemporal multiphasic acquisition allowed imaging of both the angiographic and late arterial phase in 30 of 38 studies with good image quality. Maximal lesion enhancement compared to precontrast occurred more frequently during the late arterial phase compared to maximal lesion-to-adjacent, which occurred more frequently during the early arterial phase (P < 0.001). Common and proper hepatic arteries were visualized adequately in 100%, right hepatic artery in 94-97%, left hepatic artery in 94%, and segmental vessel in 83% of cases. Arterial variants were detected with sensitivity of 87-100% and specificity of 100%. High spatiotemporal resolution arterial phase imaging provides multiple angiographic and arterial phases in a single breath-hold, enabling accurate depiction of vascular anatomy while maintain optimal arterial phase imaging for characterization of focal lesions.

High resolution multi-arterial phase MRI improves lesion contrast in chronic liver disease.

To determine the reliability of arterial phase capture and evaluate hypervascular lesion contrast kinetics with a combined view-sharing and parallel imaging dynamic contrast-enhanced acquisition, DIfferential Sub-sampling with Cartesian Ordering (DISCO), in patients with known chronic liver disease. A retrospective review of 3T MR images from 26 patients with known chronic liver disease referred for hepatocellular carcinoma surveillance or post-treatment follow up was performed. After administration of a gadolinium-based contrast agent, a multiphasic acquisition was obtained in a 28 s breath-hold, from which seven sequential post-contrast image volumes were reconstructed. The late arterial phase was successfully captured in all cases (26/26, 95% CI 87-100%). Images obtained 26 s post-injection had the highest frequency of late arterial phase capture (20/26) and lesion detection (23/26) of any individual post-contrast time; however, the multiphasic data resulted in a significantly higher frequency of late arterial phase capture (26/26, p=0.03) and a higher relative contrast (5.37+/-0.97 versus 7.10+/-0.98, p < 0.01). Multiphasic acquisition with combined view-sharing and parallel imaging reliably captures the late arterial phase and provides sufficient temporal resolution to characterize hepatic lesion contrast kinetics in patients with chronic liver disease while maintaining high spatial resolution.