Transient severe motion in the arterial phase during gadoxetate disodium-enhanced MR imaging: evaluation of patients with multiple MR examinations

CT perfusion and MRI: A combined approach for hepatocellular carcinoma diagnosis and follow-up after locoregional treatment

OBJECTIVE

CT liver perfusion (CTLP) has been well validated for hepatocellular carcinoma (HCC) detection, characterization, and treatment response evaluation. However, its role in HCC management algorithms remains unclear. This study aims to assess the diagnostic performance of CTLP alone or as an adjunct to MRI in patients considered for- or undergoing locoregional treatment for HCC.

MATERIAL AND METHODS

Thirty-nine patients under HCC surveillance (36 male, 31 cirrhotic, 16 pretreatment, 19 post-transarterial chemoembolization, 2 post-ablation) underwent MRI and CTLP in a single center within a 45-day interval. Two readers identified and characterized all observations on MRI using Liver Imaging Reporting and Data System (LI-RADS) v2018 criteria. CTLP assessment was based on Mean Slope of Increase (MSI), Time To Peak (TTP), Hepatic arterial Blood Flow (HaBF) and Hepatic Arterial Fraction (HAF) maps and established cut-offs. Diagnostic performance of MRI, CTLP, and their combination was evaluated for treated and untreated lesions using imaging or pathology as reference standard.

RESULTS

Of the total 33 treated and 61 untreated lesions, 13 and 41 were considered viable HCCs. CTLP demonstrated 75.9 % sensitivity and 95 % specificity compared to 72.2 % and 100 % for MRI (p > 0.05). Combining both modalities increased sensitivity to 85.2 % (p < 0.05) and maintained specificity at 97.5 % (p > 0.05). The combined approach led to an LR category change in 5 treated and 19 untreated lesions and affected management in 5 cases.

CONCLUSION

CTLP and MRI have comparable diagnostic performance for HCC. A combined approach improves sensitivity, without sacrificing specificity. This approach might enable more efficient patient selection for early and individualized loco-regional treatment.

Reducing transient severe motion artifacts of gadoxetate disodium-enhanced MRI by oxygen inhalation: effective for pleural effusion but not ascites

OBJECTIVES

To evaluate the efficacy of low-flow oxygen inhalation in mitigating transient severe motion (TSM) artifacts associated with gadoxetate disodium-enhanced hepatic magnetic resonance imaging (MRI).

METHODS

Patients undergoing gadoxetate disodium-enhanced MRI were included. During the examination, the experimental group received oxygen at 2 L/min via nasal cannula, while the control group did not. Images and TSM scores were evaluated and compared across precontrast, arterial, venous, and hepatobiliary phases. Subgroup analyses were conducted based on the presence of pleural effusion or ascites.

RESULTS

A total of 325 patients were included. The motion scores were highest in the arterial phase and lowest in the hepatobiliary phase in both groups, but were significantly lower in the experimental group (p < 0.05). The incidence of TSM was significantly lower in the experimental group (3.29%) compared to the control group (13.29%, p = 0.01). While pleural effusion was associated with reduced image quality in both groups (p < 0.05), the image quality in the pleural effusion category was higher in the experimental group than in the control group. Oxygen inhalation showed limited efficacy in mitigating TSM related to ascites.

CONCLUSIONS

Low-flow oxygen inhalation can effectively reduce the occurrence of gadoxetate disodium-related TSM. Pleural effusion may impair respiratory function and contribute to TSM, which can be alleviated by oxygen supplementation. However, Oxygen inhalation is less effective under the condition of ascites.

Optimized Breath-Hold Compressed-Sensing 3D MR Cholangiopancreatography at 3T: Image Quality Analysis and Clinical Feasibility Assessment

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.

Respiratory motion artefacts in Gd-EOB-DTPA (Primovist/Eovist) and Gd-DOTA (Dotarem)-enhanced dynamic phase liver MRI after intensified and standard pre-scan patient preparation: A bi-institutional analysis

Objective

The objective of this study is to evaluate if intensified pre-scan patient preparation (IPPP) that comprises custom-made educational material on dynamic phase imaging and supervised pre-imaging breath-hold training in addition to standard informative conversation with verbal explanation of breath-hold commands (standard pre-scan patient preparation–SPPP) might reduce the incidence of gadoxetate disodium (Gd-EOB-DTPA)-related transient severe respiratory motion (TSM) and severity of respiratory motion (RM) during dynamic phase liver MRI.

Material and methods

In this bi-institutional study 100 and 110 patients who received Gd-EOB-DTPA for dynamic phase liver MRI were allocated to either IPPP or SPPP at site A and B. The control group comprised 202 patients who received gadoterate meglumine (Gd-DOTA) of which each 101 patients were allocated to IPPP or SPPP at site B. RM artefacts were scored retrospectively in dynamic phase images (1: none– 5: extensive) by five and two blinded readers at site A and B, respectively, and in the hepatobiliary phase of the Gd-EOB-DTPA-enhanced scans by two blinded readers at either site.

Results

The incidence of TSM was 15% at site A and 22.7% at site B (p = 0.157). IPPP did not reduce the incidence of TSM in comparison to SPPP: 16.7% vs. 21.6% (p = 0.366). This finding was consistent at site A: 12% vs. 18% (p = 0.401) and site B: 20.6% vs. 25% (p = 0.590). The TSM incidence in patients with IPPP and SPPP did not differ significantly between both sites (p = 0.227; p = 0.390). IPPP did not significantly mitigate RM in comparison to SPPP in any of the Gd-EOB-DTPA-enhanced dynamic phases and the hepatobiliary phase in patients without TSM (all p≥0.072). In the Gd-DOTA control group on the other hand, IPPP significantly mitigated RM in all dynamic phases in comparison to SPPP (all p≤0.031).

Conclusions

We conclude that Gd-EOB-DTPA-related TSM cannot be mitigated by education and training and that Gd-EOB-DTPA-related breath-hold difficulty does not only affect the subgroup of patients with TSM or exclusively the arterial phase as previously proposed.

Multiparametric imaging for detection and characterization of hepatocellular carcinoma using gadoxetic acid-enhanced MRI and perfusion-CT: which parameters work best?

Background

MRI and perfusion-CT (PCT) are both useful imaging techniques for detection and characterization of liver lesions. The aim of this study was to compare the diagnostic accuracy of imaging parameters derived from PCT and gadoxetic acid-enhanced MRI in patients with hepatocellular carcinoma (HCC).

Methods

36 patients with liver cirrhosis and a total of 67 lesions referred to our hospital for multi-parametric diagnosis of HCC-suspected liver lesions in the setting of liver cirrhosis were prospectively enrolled and underwent PCT and MRI. HCC diagnosis was confirmed either by histology (n = 60) or interval growth (n = 7). For PCT, mean/max blood flow (BF), blood volume (BV), k-trans, arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI) were quantified. Two readers identified the lesions based on single maps each being blinded to the number of lesions.

MRI-protocol included fat-suppressed T1w-VIBE sequences obtained before, 2, 5, 10 and 20 min after the injection of gadoxetic acid as well as non-enhanced coronal HASTE, axial T1w-VIBE, fat-suppressed T2w-TSE and DWI. Quantitative analysis was performed using enhancement ratios between tumor and liver parenchyma for post-contrast in the hepatobiliary phase (RIR_HB), arterial (ER_a) and late-venous (ER_v) phases as well as signal intensity ratios (liver/parenchyma) on T1w (RIR_T1) and T2w (RIR_T2).

Results

In PCT analysis, all lesions exhibited high BF_max values (63–250 mL/100 g tissue) and were visible on HPI maps with high degrees of arterial blood supply of (HPI > 96%).

In MRI, RIR_HB was negative in 8/67. 12/67 HCCs were missed on DWI. 46/67 HCCs showed wash-in and 47/67 HCC showed wash-out of contrast agent. 6/67 HCCs were missed on T1w and 11/67 were missed on T2w-sequences when analyzed separately, while analysis of multiparametric MRI combining typical enhancement pattern, visibility on hepatobiliary phase and T1w-images the same number of lesions as PCT irrespective of their size (1–19 cm) were detected. Quantification of early enhancement by ER_a or ER_v did not improve detection rates.

Conclusions

Perfusion-CT and gadoxetic acid-enhanced MRI were comparable in detecting HCC lesions. For PCT a mean HPI > 96% proved to be a very robust parameter for detection and characterization of HCC.