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

The timing phase affected the inconsistency of APHE subtypes of liver observations in patients at risk for HCC on the multi-hepatic arterial phase imaging

OBJECTIVE

To investigate whether liver observations in patients at risk for hepatocellular carcinoma (HCC) display inconsistent arterial phase hyperenhancement (APHE) subtypes on the multi-hepatic arterial phase imaging (mHAP) and to further investigate factors affecting inconsistent APHE subtype of observations on mHAP imaging.

METHODS

From April 2018 to June 2021, a total of 141 patients at high risk of HCC with 238 liver observations who underwent mHAP MRI acquisitions were consecutively included in this retrospective study. Two experienced radiologists reviewed individual arterial phase imaging independently and assessed the enhancement pattern of each liver observation according to LI-RADS. Another two experienced radiologists identified and recorded the genuine timing phase of each phase independently. When a disagreement appeared between the two radiologists, another expert participated in the discussion to get a final decision. A separate descriptive analysis was used for all observations scored APHE by the radiologists. The Kappa coefficient was used to determine the agreement between the two radiologists. Univariate analysis was performed to investigate the factors affecting inconsistent APHE subtype of liver observations on mHAP imaging.

RESULTS

The interobserver agreement was substantial to almost perfect agreement on the assessment of timing phase (κ = 0.712-0.887) and evaluation of APHE subtype (κ = 0.795-0.901). A total of 87.8% (209/238) of the observations showed consistent nonrim APHE and 10.2% (24/238) of the observations showed consistent rim APHE on mHAP imaging. A total of 2.1% (5/238) of the liver observations were considered inconsistent APHE subtypes, and all progressed nonrim to rim on mHAP imaging. 87.9% (124/141) of the mHAP acquisitions were all arterial phases and 12.1% (17/141) of the mHAP acquisitions obtained both the arterial phase and portal venous phase. Univariate analysis was performed and found that the timing phase of mHAP imaging affected the consistency of APHE subtype of liver observations. When considering the timing phase and excluding the portal venous phase acquired by mHAP imaging, none of the liver observations showed inconsistent APHE subtypes on mHAP imaging.

CONCLUSION

The timing phase which mHAP acquisition contained portal venous phase affected the inconsistency of APHE subtype of liver observations on mHAP imaging. When evaluating the APHE subtype of liver observations, it's necessary to assess the timing of each phase acquired by the mHAP technique at first.

Time resolved DCE-MRI of the kidneys: Evaluation of the renal vasculatures and tumors using F-DISCO with and without compressed sensing in normal and wide-bore 3T systems

Dynamic contrast-enhanced MR imaging (DCE-MRI) has been widely used for the evaluation of renal arteries. This method is also useful for tumor and renal parenchyma characterization. The very fast MRI may provide stable and precise information regarding vasculature and soft tissues. The purpose of this study was to evaluate the ability of DCE-MRI to assess renal vasculatures and tumor perfusions using Differential subsampling with Cartesian ordering with spectrally selected inversion recovery with adiabatic pulses (F-DISCO) with and without compressed sensing (CS) in normal and wide-bore 3T systems. Fifty-one patients who underwent DCE-MRI using F-DISCO with or without CS for evaluation of renal or adrenal regions were included. Image quality, artifacts, fat saturation, and selective visual recognition of renal vasculatures were assessed by using a 5-point scale. Tumor recognition was verified by using a 5-point scale of confidence level. Signal intensities of each structure were also measured. In all cases, the temporal resolution of each phase for DCE-MRI was 1.9 to 2.0 seconds. Image quality, artifacts, fat saturation, and selective visual recognition of vasculatures were all acceptable (mean score 4.2-4.9). The selective visualization of renal arteries and veins was successfully accomplished (mean score 4.0-4.9). Contrast media perfusion for renal vasculature, renal parenchyma, and tumors was also recognized. DCE-MRI for the evaluation of renal vasculatures and tumors using F-DISCO with or without CS can be performed with high temporal and spatial resolutions in normal and wide-bore 3T systems. This information can be obtained in a stable fashion throughout the dynamic contrast study. CS can additionally provide benefits that the total imaging time may be shorter than without CS.

Evaluation of late arterial acquisition and image quality after gadoxetate disodium injection using the CDT-VIBE sequence

To explore the applicability of multi-arterial phase imaging technique in gadoxetate disodium-enhanced MRI. We studied 140 consecutive patients with suspected liver lesions who underwent gadoxetate disodium-enhanced MRI before surgery. All patients were randomized into three groups: group A (n = 50) was examined with VIBE-based single-artery phase imaging, group B (n = 44) with StarVIBE, and group C (n = 46) with CAIPIRINHA-Dixon-TWIST-VIBE (CDT-VIBE)-based multi-artery phase imaging. We evaluated the display rate of late arterial images and image quality in arterial phase images. We performed a study of 140 consecutive patients suspected with liver lesions who received gadoxetate disodium-enhanced MRI examination before surgery. All patients were randomly divided into three groups: group A (n = 50) was examined with single arterial phase imaging based on VIBE, group B (n = 44) was based on StarVIBE and group C (n = 46) was analyzed with multi-arterial phase imaging based on CAIPIRINHA-Dixon-TWIST-VIBE (CDT-VIBE). We evaluated the display rate of late arterial images and the image quality of dynamically enhanced images. Both radiologists had an almost perfect agreement (Kappa value > 0.8) in the assessment of late arterial and image quality. For late arterial acquisition, group C was superior to groups A and B (x² = 18.940, P < 0.05); The image of phase 4 had the highest display rate in the late artery phase. For arterial phase image quality, there was no difference between groups A, B and C at five phases (H = 10.481, P = 0.106); and the best image quality score was lower in group C than in groups A and B (H = 8.573, P = 0.014).For the quality of the late arterial images, there was a statistical difference between the best images in groups A, B and C (H = 6.619, P = 0.037), and the images in group C were significantly better than those in group A (P_.adj < 0.05). By applying multi-arterial phase acquisition based on CDT-VIBE, gadoxetate disodium-enhanced MRI scanning can obtain a better late arterial phase and provide high-quality images with fewer motion artifacts.

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

Objective

To 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 Methods

Thirty 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.

Results

Using 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.

Conclusion

CE-DISCO imaging can be an effective method for preoperative perforator imaging before ALT flap transplantation.

Clinical usefulness of multiple arterial-phase images in gadoxetate disodium-enhanced magnetic resonance imaging: a systematic review and meta-analysis

OBJECTIVES

The multiple arterial-phase (AP) technique was introduced for liver MRI, but it is not really known if multiple AP MRI (MA-MRI) improves image quality and lesion detection rate on gadoxetate disodium-enhanced MRI in comparison with single AP MRI (SA-MRI). We aimed to determine the clinical usefulness of MA-MRI in comparison with SA-MRI.

METHODS

Original articles reporting the percentage of adequate AP imaging and the lesion detection rate on gadoxetate disodium-enhanced MA-MRI were identified in PubMed, EMBASE, and Cochrane Library databases. The pooled percentage of adequate AP imaging and lesion detection rate were calculated using random-effects meta-analysis of single proportions. Subgroup analysis was performed to explain causes of study heterogeneity, and publication bias was evaluated using Egger's test.

RESULTS

Of 772 articles screened, 22 studies in 12 articles were included: 18 studies (ten MA-MRI and eight SA-MRI) suitably defined the percentage of adequate AP imaging and four (three MA-MRI and one SA-MRI) defined the lesion detection rate. MA-MRI had 16.1% higher pooled percentage of adequate AP imaging than SA-MRI (94.8% vs. 78.7%, p < 0.01). MA-MRI additionally detected 33.2% of lesions than SA-MRI (83.2% vs. 50.0%, p = 0.06). Substantial study heterogeneity was found in MA-MRI, and the definition of adequate AP imaging, lesion characteristics, and reference standards were significant factors affecting study heterogeneity (p ≤ 0.02). Significant publication bias was found in MA-MRI (p < 0.01) but not in SA-MRI studies (p = 0.87).

CONCLUSIONS

Gadoxetate disodium-enhanced MA-MRI may be more clinically useful than SA-MRI, but further study is necessary to validate this finding because of study heterogeneity and publication bias.

KEY POINTS

• Multiple arterial-phase MRI (MA-MRI) had a 16.1% higher pooled percentage of adequate AP imaging than single arterial-phase MRI (SA-MRI) (94.8% vs. 78.7%, p < 0.01). • MA-MRI additionally detected an extra 33.2% of lesions compared with SA-MRI (83.2% vs. 50.0%, p = 0.06). • Substantial study heterogeneity and significant publication bias were found across MA-MRI studies.

A New Diagnostic Criterion with Gadoxetic Acid-Enhanced MRI May Improve the Diagnostic Performance for Hepatocellular Carcinoma

BACKGROUND

To prospectively establish and validate new diagnostic criterion (DC) for liver-specific contrast agents and further compared the diagnostic sensitivity and specificity with conventional DC.

METHODS

Institutional Review Board approved and written informed consent were obtained for this prospective study. Two board-certified reviewers established the reference standard as hepatocellular carcinoma (HCC), non-HCC lesions by using marks on all cross-sectional MR images. Another 2 abdominal radiologists independently performed the marked lesion observations using 5 different DCs, including DC-1: arterial phase hyperenhancement (APHE) and portal venous phase washout; DC-2: APHE and hepatobiliary phase (HBP) hypointensity; DC-3: APHE and diffusion-weighted imaging (DWI) hyperintensity; DC-4: HBP hypointensity and DWI hyperintensity; DC-5: HBP hypointensity, DWI hyperintensity and excluded these markedly T2 hyperintensity. Diagnostic performance of sensitivity, specificity, and accuracy for each imaging DC was calculated, per-lesion diagnostic sensitivity and specificity of imaging criteria were compared by using McNemars test.

RESULTS

A total of 215 patients were included (mean age 53.82 ± 11.24 years; range 24-82 years) with 265 hepatic nodules (175 HCCs and 90 non-HCCs). The DC-4 (93.71%; 164/175) and DC-5 (92.57%; 162/175) yielded the highest diagnostic sensitivity and was better than DC-1 (72.57%; 127/175), DC-2 (82.86%; 145/175), and DC-3 (82.29%; 144/175) (all p < 0.001). The specificity of DC-1 (94.44%; 85/90) was significantly higher than that with DC-2 (83.33%; 75/90), DC-3 (84.44%; 76/90), DC-4 (74.44%; 67/90), and DC-5 (82.22%; 74/90) (all p < 0.05). Additionally, the DC-4 and DC-5 achieved the highest area under curve value of 0.841 (95% CI 0.783-0.899) and 0.874 (95% CI 0.822-0.925).

CONCLUSIONS

The combined use of HBP hypointensity and DWI hyperintensity as a new DC for HCC enables a high diagnostic sensitivity and comparable specificity.

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

BACKGROUND

In clinical practice arterial anatomy evaluation is often determined using computed tomographic angiography (CTA); the effect of enhanced MRI has been neglected.

PURPOSE

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.

STUDY TYPE

A prospective, randomized trial.

SUBJECTS

In all, 130 patients (mean age, 55.81 ± 9.43 years; range, 35-78 years) including 89 men and 41 women.

FIELD STRENGTH/SEQUENCE

3.0T, DISCO, liver acquisition with volume acceleration-flexible (LAVA-Flex), CTA.

ASSESSMENT

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.

STATISTICAL TESTS

Kendall's W-test, χ² test, Mann-Whitney U-test, and Kruskal-Wallis one-way analysis of variance (ANOVA) test.

RESULTS

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.

DATA CONCLUSION

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.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1766-1776.