The detection and discrimination of malignant and benign focal hepatic lesions:T₂weightedvsdiffusion-weighted MRI

Abstract

Objective: The purpose of this study was to evaluate the use of diffusion-weighted imaging (DWI) for the detection and characterisation of focal hepatic lesions compared with the use of T 2 weighted imaging. Method: 45 patients with 97 hepatic lesions (51 malignant lesions and 46 benign lesions) were included in this retrospective study. Malignant hepatic lesions included 12 hepatocellular carcinomas, 26 metastases and 13 intrahepatic cholangiocarcinomas. Benign hepatic lesions included 19 haemangiomas and 27 cysts. The MRI protocol for the upper abdomen included T 2 weighted images, in-and opposed-phase T 1 weighted images and dynamic T 1 weighted images. Breath-hold fat-suppressed single-shot echo planar DWI was performed with the following parameters: 1338/66; b factors, 0, 50 and 800 s mm -2 . Two independent observers reviewed the T 2 weighted images and the DWI to detect and to characterise the hepatic lesions. Results: For detection of malignant hepatic lesions, the use of DWI showed a significantly higher detection rate than the use of T 2 weighted images (p,0.05). However, there was no significant difference between the use of DWI and T 2 weighted images for benign hepatic lesions. For the differentiation between malignant and benign hepatic lesions, there was no significant difference in sensitivity, specificity and accuracy between the use of T 2 weighted images and the use of DWI. Conclusion: The use of DWI was better for the detection of malignant hepatic lesions than the use of T 2 weighted images. However, for detection of benign hepatic lesions and characterisation of hepatic lesions, the use of DWI was equivalent to the use of T 2 weighted images. Accurate detection and characterisation of focal hepatic lesions is important for treatment planning in patients with hepatic tumours. For the detection and characterisation of hepatic lesions, CT and MRI are usually employed [1,2]. MRI, T 1 weighted, T 2 weighted and gadoliniumenhanced T 1 weighted imaging have been commonly utilised [3,4].With rapid progress of the use of parallel imaging techniques such as sensitivity encoding (SENSE), the quality of diffusion weighted single-shot echo-planar imaging has improved [5]. Diffusion-weighted MRI of the abdomen has become possible by the use of this technique, which reduces acquisition time, minimises echo-planar imaging artefacts and improves the quality of images [5].Several studies have characterised focal hepatic lesions by measurement of the lesion apparent diffusion coefficient (ADC) [6][7][8][9][10][11] and have evaluated detection of focal hepatic lesion by use of diffusion-weighted imaging (DWI) [12][13][14][15][16]. However, there is still controversy regarding the value of DWI for the characterisation of focal hepatic lesions as the ADC values of different types of lesions overlap [6][7][8][9][10][11]. Furthermore, a limited number of studies have been performed using DWI for the detection of hepatic lesions [12][13][14][15][16].The purpose of this study was to evaluate the use of DWI for the d...

Diffusion-weighted imaging of the liver: Current applications

“…DWI has a higher detection rate of liver tumors than T2WI[64,65], particularly in detecting malignant lesions[66]. However, the ADC of benign solid lesions has been reported to be similar to that of the liver parenchyma[67].…”

Could ADC values be a promising diagnostic criterion for differentiating malignant and benign hepatic lesions in Asian populations

“…The extracted useable data and the study characteristics of each article are summarized in Table 1. In the study by Yang et al, [32] an analysis of DWI images was performed independently by 2 observers; thus, 2 subsets of data from the study were included. Therefore, we extracted 9 subsets of data from all 8 studies.…”

“…[24–26] With the current development of the advanced respiratory gating technique and sensitivity encoding, abdominal DW-MRI has been increasingly used in diseases of the liver, the imaging of which was formerly restricted by respiratory movement. DWI has been used to assess the degree of hepatic fibrosis, [27–30] detect hepatic lesions, [31–34] and differentiate malignant from benign lesions [32,35–41] independently from T1 and T2 relaxation times and without the need for contrast agent administration.…”

“…Therefore, the ADC was thought to have the potential to differentiate benign from malignant hepatic lesions. Several studies [32,35–41] have indicated that the reported ADC values of benign and malignant hepatic lesions ranged from 1.55 to 7.58 and 0.68 to 3.15 (×10 −3  mm 2 /s), respectively, resulting in several recommended ADC cut-off values, but there were also variable degrees of overlap between these values. In these studies, different DWI sequence parameters, such as the set of b values or the use of the parallel imaging technique, may lead to different ADC values for liver lesions, consequently resulting in various cut-off values for differentiating malignant and benign lesions, and overlapping ADC values for malignant and benign lesions.…”

Impact of field strength and RF excitation on abdominal diffusion-weighted magnetic resonance imaging

“…The technique may be useful in determining pathology in the liver (degree of cirrhosis/fibrosis), kidneys (lesion characterization, renal failure, pyelonephritis), pancreas (pancreatitis and pancreatic cancer), bowel (Crohn's disease), and uterus (endometriosis) [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] . In a recent meta-analysis, Li et al [19] has shown a potential future role for this type of sequence to assess for cancers within the liver.…”