Triple Arterial Phase Research Articles

Application of a deep learning algorithm for three-dimensional T1-weighted gradient-echo imaging of gadoxetic acid-enhanced MRI in patients at a high risk of hepatocellular carcinoma.

To evaluate the efficacy of a vendor-specific deep learning reconstruction algorithm (DLRA) in enhancing image quality and focal lesion detection using three-dimensional T1-weighted gradient-echo images in gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) in patients at a high risk of hepatocellular carcinoma. In this retrospective analysis, 83 high-risk patients with hepatocellular carcinoma underwent gadoxetic acid-enhanced liver MRI using a 3-T scanner. Triple arterial phase, high-resolution portal venous phase, and high-resolution hepatobiliary phase images were reconstructed using conventional reconstruction techniques and DLRA (AIRTM Recon DL; GE Healthcare) for subsequent comparison. Image quality and solid focal lesion detection were assessed by three abdominal radiologists and compared between conventional and DL methods. Focal liver lesion detection was evaluated using figures of merit (FOMs) from a jackknife alternative free-response receiver operating characteristic analysis on a per-lesion basis. DLRA-reconstructed images exhibited significantly improved overall image quality, image contrast, lesion conspicuity, vessel conspicuity, and liver edge sharpness and reduced subjective image noise, ringing artifacts, and motion artifacts compared to conventionally reconstructed images (all P < 0.05). Although there was no significant difference in the FOMs of non-cystic focal liver lesions between the conventional and DL methods, DLRA-reconstructed images showed notably higher pooled sensitivity than conventionally reconstructed images (P < 0.05) in all phases and higher detection rates for viable post-treatment HCCs in the arterial and hepatobiliary phases (all P < 0.05). Implementing DLRA can enhance the image quality in 3D T1-weighted gradient-echo sequences of gadoxetic acid-enhanced liver MRI examinations, leading to improved detection of viable post-treatment HCCs.

Confirmed and presumed canine insulinomas and their presumed metastases are most conspicuous in the late arterial phase in a triple arterial phase CT protocol.

Arterial enhancement is the commonly described characteristic of canine insulinomas in contrast-enhanced computed tomography (CECT). However, this finding is also reported as inconsistent. The main aim of this single-center retrospective observational study was to describe the contrast enhancement (CE) pattern of canine presumed and confirmed insulinomas and presumed metastases in three consecutive (early, mid, and late) arterial phases. Included dogs had a medical-record-based clinical or cytological/histopathological diagnosis of insulinoma and quadruple-phase CECT.The arterial phases were identified according to published literature. The arterial enhancement of confirmed and presumed lesions was assessed using a visual grading score. Twelve dogs with a total of 17 pancreatic nodules were analyzed. Three dogs had multiple pancreatic nodules and nine had solitary findings. Four insulinomas were histopathologically confirmed. Late arterial phase (LAP) images demonstrated the largest number of pancreatic nodules reaching the highest enhancement scores (n=13, 76%). All analyzed dogs had CT evidence of arterially enhancing nodules in the liver (n=12), seven in the hepatic, splenic, or colic lymph nodes, and three in the spleen. Three out of five sampled livers and three lymph nodes were metastatic. All sampled spleens were benign. Avid arterial enhancement was the most dominant feature of canine presumed and confirmed insulinomas and presumed metastases in quadruple-phase CECT. The highest enhancement scores were observed primarily in LAP, followed by MAP. Authors, therefore, recommend including LAP in the standard CT protocol for dogs with suspected pancreatic insulinomas.

Triple arterial phase in the dynamic post-contrastografic MRI study of liver lesions: comparative study

The objective of our work was to assess the accuracy in terms of spatial and contrast resolution, respiratory movement artifacts and synchronization of the “triple arterial phase” (TAP) sequence and compare it with the conventionally acquired arterial phase (AP). Between June 2021 and September 2021 16 patients underwent liver MRI for characterization and/or follow-up of focal hepatic lesions, and the TAP sequence was used. With the aim to obtain a TAP sequence we applied the KEYHOLE technique (modified to 35%) and the CENTRA-Keyhole method (Contrast Enhanced Timing Robust Angiography) for the K-space sampling, to the basic e-THRIVE sequence. 6/16 patients had previous MRI examinations performed with the classic single AP. Five radiologists experienced in the interpretation of liver imaging independently examined MRI studies. They were asked to provide their opinion, by using a qualitative evaluation scale, on spatial resolution, contrast/noise ratio (CNR), presence of breath-hold artifacts, synchronization of the TAP and its quality and usefulness for the characterization of liver lesions. The same questions were used for the evaluation of the 6/16 previous MRI examinations acquired with the conventional AP. For all readers, with TAP, the synchronization of the arterial study, the spatial resolution, the evaluation of artifacts from incorrect breath-hold were deemed good or excellent. The contrast resolution in the TAP was excellent for almost all cases. TAP was overall judged superior to AP. These preliminary results obtained are promising and require confirmation on a larger sample study to assess the diagnostic benefit of the TAP.

Triple arterial phase in the dynamic post-contrastografic MRI study of liver lesions: comparative study

The objective of our work was to assess the accuracy in terms of spatial and contrast resolution, respiratory movementartifacts and synchronization of the “triple arterial phase” (TAP) sequence and compare it with the conventionallyacquired arterial phase (AP). Between June 2021 and September 2021 16 patients underwent liver MRI forcharacterization and/or follow-up of focal hepatic lesions, and the TAP sequence was used. With the aim to obtain aTAP sequence we applied the KEYHOLE technique (modified to 35%) and the CENTRA-Keyhole method (ContrastEnhanced Timing Robust Angiography) for the K-space sampling, to the basic e-THRIVE sequence. 6/16 patients hadprevious MRI examinations performed with the classic single AP. Five radiologists experienced in the interpretationof liver imaging independently examined MRI studies. They were asked to provide their opinion, by using a qualitativeevaluation scale, on spatial resolution, contrast/noise ratio (CNR), presence of breath-hold artifacts, synchronizationof the TAP and its quality and usefulness for the characterization of liver lesions. The same questions were used forthe evaluation of the 6/16 previous MRI examinations acquired with the conventional AP. For all readers, with TAP,the synchronization of the arterial study, the spatial resolution, the evaluation of artifacts from incorrect breathhold were deemed good or excellent. The contrast resolution in the TAP was excellent for almost all cases. TAP wasoverall judged superior to AP. These preliminary results obtained are promising and require confirmation on a largersample study to assess the diagnostic benefit of the TAP.

Effects of gadoxetic acid on image quality of arterial multiphase magnetic resonance imaging of liver: comparison study with gadoteric acid-enhanced MRI.

To compare the effects of gadoxetic acid and gadoteric acid on the image quality of single-breath-hold, triple (first, second, and third) arterial hepatic magnetic resonance imaging (MRI). Two hundred and eleven patients were divided into two groups according to the contrast materials used (gadoxetic acid, 108 patients and gadoteric acid, 103 patients). All 3.0-T MR examinations included triple arterial phase acquisition using the 4D enhanced T1-weighted high-resolution isotropic volume examination (eTHRIVE) keyhole technique. The image qualities of the pre-contrast and triple arterial phases were assessed in terms of image artifacts, sharpness of the intrahepatic vessel and liver edge, and overall image quality with a 5-point scale for qualitative analysis. The image quality of gadoxetic acid-enhanced liver MRI in the triple arterial phases was significantly degraded compared with that of gadoteric acid-enhanced liver MRI, although better image scores were observed in the pre-contrastimages in the gadoxetic acid group (P < 0.001). The overall image quality gradually improved from the first to the third arterial phases in both groups (P < 0.003). Intravenous gadoxetic acid could have a detrimental effect on image quality of triple arterial phase MRI with the 4D eTHRIVE Keyhole technique. The third arterial phase images had the best image qualities; thus, they could be used as key scans.

Comparison of Triple Arterial Phase between TWIST-VIBE by View Sharing Technique and Independent-VIBE for Liver MRI

Comparison of Triple Arterial Phase between TWIST-VIBE by View Sharing Technique and Independent-VIBE for Liver MRI

Triple Arterial Phase CT of the Liver with Radiation Dose Equivalent to That of Single Arterial Phase CT: Initial Experience.

Purpose To develop and evaluate a triple arterial phase CT liver protocol with a similar radiation dose to that of standard single arterial phase CT in study subjects suspected of having hepatocellular carcinoma (HCC). Materials and Methods The study consisted of a retrospective part A for protocol development (n = 15) and a prospective part B to evaluate diagnostic accuracy (n = 38). All 53 participants underwent perfusion CT with 50 mL contrast material between August 2013 and September 2014. Group B underwent an additional standard multiphasic liver CT examination with 120 mL of contrast material (range, 70-143 mL). Image sets from triple arterial phase imaging were reconstructed from perfusion CT by fusing images from three dedicated arterial time points. Triple arterial phase CT and standard single arterial phase CT were compared by two readers, who assessed subjective image quality and HCC detection rate. A third reader served as reference reader and assessed objective image quality. The paired Student t test, Wilcoxon signed rank test, jackknife alternative free-response receiver operating characteristic (JAFROC), and JAFROC curve were applied. Results The mean volume CT dose index was 11.6 mGy for triple arterial phase CT and 11.9 mGy for standard single arterial phase CT (P = .73). Triple arterial phase CT showed lower image noise and better contrast-to-noise ratio compared with standard single arterial phase CT (P < .001 and P = .032, respectively); however, there was no significant difference in lesion-to-liver-contrast ratio (P = .31). Subjective image quality was good for both protocols. The detection rate of the 65 HCC lesions was 82% for reader 1 and 83% for reader 2 at triple arterial phase CT and 80% for reader 1 and 77% for reader 2 at standard single arterial phase CT (P = .4). Conclusion Triple arterial phase imaging is feasible at the same radiation dose as that used for standard single arterial phase CT. Triple arterial phase imaging provides equivalent to superior image quality and equal HCC detection rate despite the use of less than half the contrast material dose used at standard single arterial phase CT. © RSNA, 2018.

Multiple arterial phase MRI of arterial hypervascular hepatic lesions: improved arterial phase capture and lesion enhancement.

To establish if triple-phase arterial imaging improves the detection of arterial phase hyperintense lesions based on arterial phase capture, motion artifact degradation, and lesion enhancement when compared to single-phase imaging. Patients at risk for hepatocellular carcinoma were imaged at 3.0T. Seventy-three consecutive patients with a standard single-phase MRI and eighty-five consecutive patients were imaged using extracellular contrast with triple arterial phase MRI using three sequential accelerated acquisitions of 8s. Arterial phase capture and image quality were qualitatively categorized. Forty single-phase and forty-four triple-phase studies contained arterially enhancing lesions>1cm with washout appearance. The contrast-to-noise ratio (CNR) of the lesions was calculated. We compared the differences in means with Student t-tests and those in arterial phase capture with a Chi squared test with Yates correction. The triple-phase acquisitions captured the early or late arterial phases more frequently than did the single-phase acquisition (99% vs 86%; P value=0.006). Triple-phase also provided greater number of patients with early or late arterial phase imaging without motion artifact (92% vs 79%, P-value=0.05). The lesion analysis revealed increased maximum CNR in the triple-phase imaging (704.4) vs. single-phase imaging (517.2), P-value<0.001. Triple-phase acquisition provides more robust arterial phase imaging for hepatic lesions, with increased lesion CNR, compared to standard single-phase arterial phase imaging.

Optimal visualization of focal nodular hyperplasia: quantitative and qualitative evaluation of single and multiphasic arterial phase acquisition at 1.5T MR imaging.

To evaluate the qualitative and quantitative benefit of multiple arterial phase acquisitions for the depiction of hypervascularity in FNH explored MR imaging using an extracellular contrast agent. Between 2007 and 2014, all patients who underwent MR imaging for the exploration of FNH were included. The protocol included a single or a triple arterial phase ("single" and "triple" group, respectively). Arterial phases were visually divided into four types: (1) angiographic, (2) early, (3) late, and (4) portal. Signal intensity on arterial phase images was visually recorded as intense, moderate, or low for each lesion. Lesion-to-liver contrast (LLC) and relative lesion enhancement (RE) were calculated and compared between the two groups using the Mann-Whitney test. Thirty-five women were included (mean 45-year old, range 20-66), with 50 FNH (mean size 30mm). Single and triple groups included 20 patients (30 FNH) and 15 patients (20 FNH), respectively. Signal intensity was intense in all lesions in the triple group and in 22/30 (73%) in the single group (p=0.041). Intense signals were more frequently found in the early arterial phase (p<0.001). RE was not significantly different (1.78±0.84 vs. 1.98±1.81 p=0.430, in the single and triple groups, respectively) but LLC was significantly higher in the triple group (0.32±0.10 vs. 0.22±0.10, p=0.005). LLC was significantly higher in the first two arterial phases in the triple group (p<0.001). Acquisition of three arterial phases improves the visualization of hypervascularity of FNH, as lesions show high visual signal intensity and contrast. Optimal visualization is obtained in the early arterial phase.

Respiratory Motion Artifact Affecting Hepatic Arterial Phase Imaging with Gadoxetate Disodium: Examination Recovery with a Multiple Arterial Phase Acquisition

To determine whether the use of a multiple arterial phase imaging technique provides adequate image quality in patients experiencing transient severe motion (TSM) in the arterial phase on abdominal magnetic resonance (MR) images obtained with gadoxetate disodium. This retrospective study was approved by the institutional review board and was compliant with HIPAA. The requirement to obtain informed consent was waived. Five hundred forty-nine consecutive MR examinations were evaluated, 345 performed with gadoxetate disodium and 204 performed with gadobenate dimeglumine. All examinations included single-breath-hold triple arterial phase acquisition. Five radiologists blinded to the contrast material rated motion on a scale of 1 (no motion) to 5 (nondiagnostic images) for the precontrast phase, the three arterial phases, the portal venous phase, and the late dynamic phase. Adequacy of late hepatic arterial timing was also rated for the each of the three arterial phases. Mean motion scores were compared by using the Wilcoxon signed rank test. The number of patients with TSM, as well as the number of those with "adequate" arterial phases, was compared with the χ(2) or Fisher exact test, as appropriate. Mean motion scores in all three arterial phases in the gadoxetate disodium cohort were significantly worse than those in the gadobenate dimeglumine cohort (P < .005). TSM occurred at a higher rate with gadoxetate disodium than with gadobenate dimeglumine (10.7% [37 of 345 examinations] vs 0.5% [one of 204 examinations], P < .001). However, 30 of 37 examinations affected by TSM had at least one well-timed arterial phase with a mean motion score of 3 or less and were thus considered adequate. Use of single-breath-hold multiple arterial phase acquisition in abdominal MR imaging with gadoxetate disodium recovers most arterial phases that would otherwise have been compromised by transient motion.

Triple Arterial Phase Hepatic MRI Using Four Dimensional T1-Weighted High Resolutions Imaging with Volume Excitation Keyhole Techniques: Feasibility and Initial Clinical Experience in Focal Liver Lesions

Triple Arterial Phase Hepatic MRI Using Four Dimensional T1-Weighted High Resolutions Imaging with Volume Excitation Keyhole Techniques: Feasibility and Initial Clinical Experience in Focal Liver Lesions

Triple Arterial Phase Dynamic MRI with Sensitivity Encoding for Hypervascular Hepatocellular Carcinoma: Comparison of the Diagnostic Accuracy Among the Early, Middle, Late, and Whole Triple Arterial Phase Imaging

We assessed and compared the diagnostic accuracy of the early, middle, late, and whole triple arterial phase MRI with sensitivity encoding (SENSE) for the detection of hypervascular hepatocellular carcinoma (HCC). Thirty-one patients with 102 HCCs underwent dynamic MRI with SENSE. The findings of CT examinations, combined with those of visceral angiography or histopathologic examination, were used as the gold standard. After acquisition of T1- and T2-weighted images, gadolinium-enhanced triple arterial, portal, and delayed phase images were obtained. Acquisition of the triple arterial phase imaging was started at the timing of peak aortic enhancement and completed within a single breath-hold. Acquisition time for each phase was 8.4 sec. Four image sets including the early, middle, late, and whole triple arterial phase imaging were interpreted separately by four observers. The mean values of area under alternative-free-response receiver operating characteristic (AFROC) curve and of sensitivity were compared among the four image sets. The mean values of area under AFROC curve were 0.52, 0.66, 0.53, and 0.68 and of sensitivity were 45%, 64%, 48%, and 65% for the image sets with the early, middle, late, and whole triple arterial phase imaging, respectively. Both mean values were significantly higher for the image sets with the middle and whole triple arterial phase imaging than for those with the early and late arterial phase imaging. The middle arterial phase imaging with k-space centered at 12.6 sec after the peak aortic enhancement was optimal for detecting HCC and showed diagnostic accuracy equivalent to that of the whole triple arterial phase imaging.

Evaluation of optimal timing of arterial phase imaging for the detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography.

We evaluated the optimal timing of arterial phase imaging for detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography. Forty-nine patients with 90 hypervascular hepatocellular carcinomas (3 to 50 mm in diameter; mean, 18.7 mm) underwent triple arterial phase imaging of the whole liver using a multidetector-row helical computed tomography. At 20 seconds, 30 seconds, and 40 seconds after intravenous administration of 100 mL of 300 mgI/mL of nonionic contrast medium at a rate of 4 mL/s, early, middle, and late arterial phase images were obtained serially during a single breath-hold with an interscan delay of 5 seconds. Detector-row configurations of 4 mm x 4, scan pitch of 5.5, and scan time of 5 seconds for each phase were used. Forty prospective reconstruction images of 5-mm thickness for each phase were obtained. The images from each phase were interpreted separately for detection of hypervascular hepatocellular carcinoma by 3 observers independently who were unaware of tumor burden in the liver. Sensitivity, positive predictive value, and area under the receiver operating characteristic curve values for each arterial phase were calculated and compared statistically. The mean sensitivity and positive predictive values for hypervascular hepatocellular carcinoma diagnosis of blind readers were 37% and 87% for the early arterial phase, 73% and 85% for the middle arterial phase, and 49% and 81% for the late arterial phase, respectively. The middle arterial phase imaging showed significantly superior sensitivity compared with the early and late arterial phase for detecting hepatocellular carcinoma (P < 0.05). Mean area under the receiver operating characteristic curve value of the middle arterial phase imaging (0.84) was significantly higher that that of the early (0.56) or late arterial phase (0.62; P < 0.05). If a single arterial phase is used for diagnosis of hypervascular hepatocellular carcinoma, the middle phase (delay time of 30 seconds) is optimal.