Respiratory-Triggered Versus Breath-Hold Diffusion-Weighted MRI of Liver Lesions: Comparison of Image Quality and Apparent Diffusion Coefficient Values (original) (raw)
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Diffusion-weighted MRI in a liver protocol: Its role in focal lesion detection
World Journal of Radiology, 2012
AIM: To evaluate the role of diffusion-weighted imaging (�WI) in the detection of focal liver lesions (FLLs), using a conventional magnetic resonance imaging (MRI) protocol. METHODS: Fifty-two patients (22 males, average age 55.6 years, range: 25-82 years), studied using a 1.5 Tesla magnetic resonance scanner, were retrospectively analyzed; detection of FLLs was evaluated by considering the number of lesions observed with the following sequences: (1) respiratory-triggered diffusion-weighted single-shot echo-planar (�W SS-EP) sequences; (2) fat-suppressed fast spin-echo (fs-FSE) T2 weighted sequences; (3) steady-state free precession (SSFP) images; and (4) dynamic triphasic gadolinium-enhanced images, acquired with three-dimensional fast spoiled gradient-echo (3� FSPGR). Two radiologists independently reviewed the images: they were blinded to their respective reports. �W SS-EP sequences were compared to fs-FSE, SSFP and dynamic gadolinium-enhanced acquisitions using a t-test. Pairs were compared for the detection of: (1) all FLLs; (2) benign FLLs; (3) malignant FLLs; (4) metastases; and (5) hepatocellular carcinoma (HCC). RESULTS: Interobserver agreement was very good (weighted k = 0.926, CI = 0.880-0.971); on the consensus reading, 277 FLLs were detected. In the comparison with fs-FSE, DW SS-EP sequences had a significantly higher score in the detection of all FLLs, benign FLLs, malignant FLLs and metastases; no statistical difference was observed in the detection of hepatocellular carcinoma (HCCs). In the comparison with SSFP sequences, DW SS-EP had significantly higher scores (P < 0.05) in the detection of all lesions, benign lesions, malignant lesions, metastases and HCC. All FLLs were better detected by dynamic 3� FSGR enhanced acquisition, with P = 0.0023 for reader 1 and P = 0.0086 for reader 2 in the comparison with �W SS-EP sequences; with reference to benign FLLs, �W SS-EP showed lower values than 3� FSPGR enhanced acquisition (P < 0.05). No statistical differences were observed in the detection of malignant lesions and metastases; considering HCCs, a very slight difference was reported by reader 1 (P = 0.049), whereas no difference was found by reader 2 (P = 0.06). CONCLUSION: In lesion detection, �WI had higher scores than T2 sequences; considering malignant FLLs, no statistical difference was observed between �WI and dynamic gadolinium images.
Diffusion-weighted MRI: In differential diagnosis of liver masses
Marmara Medical Journal, 2017
Objectives: The purpose of our study was to determine apparent diffusion coefficients (ADCs) of focal liver lesions on the basis of respiratory triggered diffusion-weighted single-shot echo-planar MR imaging (DWI-SS-EPI) sequence and to evaluate whether ADC measurements can be used to characterize lesions. Patients and Methods: One hundred and eighteen patients with 134 focal liver lesions [35 cysts, 48 hemangiomas, 4 focal noduler hyperplasias (FNH), 31 metastases, 14 hepatocellular carsinomas (HCCs), 1 fibrolamellar carsinoma, 1 cholangiocellular carcinoma; mean size 18.4 mm; range 10-140 mm] were examined on a 1.5-T system using respiratory triggered DWI-SS-EPI (b-values: 50, 400, 800 s/mm 2). Results: Results were correlated with characteristic MRI findings, histopathologic data and follow-up imagings. The ADCs of different lesion types were compared and lesion differentiation using optimal thresholds for ADCs was evaluated. Mean ADCs (x10-3 mm 2 /s) were 2.15, 1.57, 1.16, 1.08, 1.03 for cysts, hemangiomas, FNHs, metastases and HCCs, respectively. Mean ADCs differed significantly for all lesion types except metastases, HCCs and FNHs. Overall, 88.5% of lesions were correctly classified as benign or malignant using a treshold value of 1.20x10-3 mm 2 /s. Conclusion: Measurements of the ADCs of focal liver lesions on the basis of a respiratory triggered DWI-SS-EPI sequence may constitute a useful supplementary method for lesion characterization.
Diffusion-weighted imaging of the liver: a comprehensive review
Current problems in diagnostic radiology
Diffusion-weighted magnetic resonance imaging is based on the Brownian motion of water and enables quantification of the apparent diffusion coefficient throughout the body. This article discusses the principles of diffusion-weighted magnetic resonance imaging, as well as the possible applications and limitations as they apply to liver imaging. This will introduce the readers to this novel magnetic resonance imaging tool, which has a promising future.
Alexandria Journal of Medicine, 2014
Introduction: Diffusion weighted imaging (DWI) offers molecular information that complements the morphologic information obtained with conventional magnetic resonance imaging (MRI) and can reflect the functions and structures of the body without trauma. Aim of the work: To assess the role of DWI as a routine sequence in a MRI study to help in differentiating liver lesions. Patients and methods: The study included 50 patients referred to do a MRI study to diagnose and/or to confirm the ultrasonographic or CT findings of focal hepatic lesions. The examination was done on 1.5T superconducting magnet MRI machines; Philips Gyroscan Intera version 12.1.1.2 (Best, The Netherlands) and Siemens Magnetom Avanto (Erlangen, Germany) machine. Results: All studied patients had a focal hepatic lesion either on top of cirrhotic liver or non cirrhotic liver. DWI was found to be helpful with the routine MRI sequences to reach the diagnosis. The final diagnosis was confirmed by histopathological examination or follow up. A cutoff value of ADC for benign lesions was found to be 1.25 • 10 À3 mm 2 /s. Conclusions: DWI should be included as a basic sequence in the routine MRI study of the liver as it helps in diagnosis and so reaching a final diagnosis or at least trying to narrow the list of differential diagnosis.
Diffusion-Weighted MR Imaging of Focal Liver Lesions in the Left and Right Lobes
Academic Radiology, 2013
Rationale and Objectives: To determine possible differences between the left and right hepatic lobes in apparent diffusion coefficient (ADC) values of benign and malignant focal liver lesions (FLLs) and normal liver parenchyma. Materials and Methods: Thirty-six patients (16 males, 20 females; mean age 56.8 years) with FLLs of the same etiology in both the left and right hepatic lobes (13 patients with 26 benign FLLs and 23 patients with 46 malignant FLLs) who underwent 1.5T magnetic resonance imaging (MRI) including diffusion-weighted MRI (b values: 0 and 800 seconds/mm) with respiratory gating and without cardiac gating were included in this Health Insurance Portability and Accountability Act-compliant and institutional review board-approved study. ADC values of normal liver parenchyma and FLLs in each hepatic lobe were calculated and compared by using Student's t-test and Wilcoxon signed-rank test, respectively.
The Medical Journal of Cairo University, 2021
Background: DWI is done by quantifying the amount of diffusion through tissues and calculating ADC values. Tumors, which consist of excessive proliferation of cells, would expectantly show restricted diffusion. ADC values can aid in characterizing focal liver lesions as benign vs. malignant. DWI when used in combination with dynamic MRI can be used to enhance the accuracy of liver lesion characterization and diagnosis. Aim of Study: To assess the role of diffusion-weighted magnetic resonance imaging (DWI) in detection and characterization of hepatic focal lesions, and its value in differentiating benign from malignant masses. Patients and Methods: A total of 60 liver disease patients (21 males and 39 females) with ages ranged from 20 to 63 years old were included in the study. All of the patients underwent MRI examination including pre-contrast imaging, dynamic study and diffusion study. The morphological features of each lesion were recorded and diffusion images were reviewed for final radiological characterization and detection of focal lesions. ADC values were calculated for all patients. Results: This study included 60 patients with various types of lesions, 40 of which had benign lesions and 20 with malignant lesions. The diffusion images aided in diagnosis of malignant lesions with different components. Absolute ADC values of different types of lesions were not similar. Benign hepatic lesions have generally higher ADC values compared with malignant lesions. The ADC values we found for different lesions were consistent with previous studies. Conclusion: Diffusion-weighted MRI sequence with quantitative ADC measurement should be used as an additional sequence to supplement conventional MRI protocol studies for proper detection and characterization of solid liver lesions.
Simultaneous Multislice Accelerated Free-Breathing Diffusion-Weighted Imaging of the Liver at 3T
Abdominal Imaging, 2015
Purpose: To perform image quality comparison between accelerated multiband diffusion acquisition (mb2-DWI) and conventional diffusion acquisition (c-DWI) in patients undergoing clinically indicated liver MRI. Methods: In this prospective study 22 consecutive patients undergoing clinically indicated liver MRI on a 3-T scanner equipped to perform multiband diffusionweighed imaging (mb-DWI) were included. DWI was performed with single-shot spin-echo echo-planar technique with fat-suppression in free breathing with matching parameters when possible using c-DWI, mb-DWI, and multiband DWI with a twofold acceleration (mb2-DWI). These diffusion sequences were compared with respect to various parameters of image quality, lesion detectability, and liver ADC measurements. Results: Accelerated mb2-DWI was 40.9% faster than c-DWI (88 vs. 149 s). Various image quality parameter scores were similar or higher on mb2-DWI when compared to c-DWI. The overall image quality score (averaged over the three readers) was significantly higher for mb-2 compared to c-DWI for b = 0 s/mm 2 (3.48 ± 0.52 vs. 3.21 ± 0.54; p = 0.001) and for b = 800 s/mm 2 (3.24 ± 0.76 vs. 3.06 ± 0.86; p = 0.010). Total of 25 hepatic lesions were visible on mb2-DWI and c-DWI, with identical lesion detectability. There was no significant difference in liver ADC between mb2-DWI and c-DWI (p = 0.12). Bland-Altman plot demonstrates lower mean liver ADC with mb2-DWI compared to c-DWI (by 0.043 9 10-3 mm 2 /s or 3.7% of the average ADC). Conclusion: Multiband technique can be used to increase acquisition speed nearly twofold for free-breathing DWI of the liver with similar or improved overall image quality and similar lesion detectability compared to conventional DWI.
Open Journal of Medical Imaging, 2013
To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from 20 -400 s/mm 2 were designed with identical parameters but with different handling of respiratory motion [respiratory triggered (RT), free breathing (FB), breath hold (BH)] on 3 T and 1.5 T. Thirteen volunteers were examined at a 3 T and six of them also at a 1.5 T magnet. DW images were analyzed quantitatively and qualitatively. Regions of interest were placed in cranial, middle and caudal parts of the right liver lobe (RLL) and ADC and SNR were calculated. Results: ADC in RLL tended to be lower at 3 T MRI. Least inter-subject ADC variability was found with RT in the middle RLL at 3 T. Highest ADCs were found caudally in the RLL. Significant differences in ADC between middle and caudal RLL were calculated in FB and RT at 3 T and FB and BH at 1.5 T, respectively. No significant difference in SNR was found between 3 T and 1.5 T. There were significantly more artifacts in the left liver lobe (LLL) compared to the RLL in all sequences and in the LLL at 3 T compared to 1.5 T. Conclusion: Our study suggests that longitudinal hepatic ADC measurements should be performed using equivalent field strength, b-values, and acquisition technique, given influence of these factors on ADC measurements.