Use Of Apparent Diffusion Coefficient Research Articles

Prostate MRI: diffusion-weighted imaging at 1.5T correlates better with prostatectomy Gleason grades than TRUS-guided biopsies in peripheral zone tumours

To investigate the usefulness of Apparent Diffusion Coefficients (ADC) in predicting prostatectomy Gleason Grades (pGG) and Scores (GS), compared with ultrasound-guided biopsy Gleason Grades (bGG). Twenty-four patients with biopsy-proven prostate cancer were included in the study. Diffusion-weighted images were obtained using 1.5-T MR with a pelvic phased-array coil. Median ADC values (b0,500,1000 s/mm²) were measured at the most suspicious areas in the peripheral zone. The relationship between ADC values and pGG or GS was assessed using Pearson's coefficient. The relationship between bGG and pGG or GS was also evaluated. Receiver operating characteristic (ROC) curve analysis was performed to assess the performance of each method on a qualitative level. A significant negative correlation was found between mean ADCs of suspicious lesions and their pGG (r = -0.55; p < 0.01) and GS (r = -0.63; p < 0.01). No significant correlation was found between bGG and pGG (r = 0.042; p > 0.05) or GS (r = 0.048; p > 0.05). ROC analysis revealed a discriminatory performance of AUC = 0.82 for ADC and AUC = 0.46 for bGG in discerning low-grade from intermediate/high-grade lesions. The ADC values of suspicious areas in the peripheral zone perform better than bGG in the correlation with prostate cancer aggressiveness, although with considerable intra-subject heterogeneity. • Prostate cancer aggressiveness is probably underestimated and undersampled by routine ultrasound-guided biopsies. • Diffusion-weighted MR images show good linear correlation with prostate cancer aggressiveness. • DWI information may be used to improve risk-assessment in prostate cancer.

Renal Cell Carcinoma: Diffusion-weighted MR Imaging for Subtype Differentiation at 3.0 T

To assess the usefulness of apparent diffusion coefficients (ADCs) for characterizing renal cell carcinoma (RCC) subtypes at 3.0 T. The Institutional Review Board approved this retrospective study, and informed consent was waived. Eighty-three patients underwent diffusion-weighted (DW) magnetic resonance (MR) imaging of 85 renal masses. In each patient, precontrast single-shot spin-echo echo-planar DW imaging was performed with b values of 0 and 500 and 0 and 800 sec/mm(2) by using a 3.0-T MR imaging system. Differences in ADCs between the RCC lesions and uninvolved renal parenchyma were tested by using a paired-samples t test. One-way analysis of variance was used to compare ADCs of the various RCC subtypes. Receiver operating characteristic (ROC) curve analysis was used to test the ability of ADCs in differentiating clear cell from non-clear cell RCCs. Pathologic diagnoses of the 85 tumors (median diameter, 4.4 cm) in the 83 patients (54 men, 29 women; age range, 23-75 years; mean age, 49.4 years) were clear cell RCC for 49 tumors, papillary RCC for 22 tumors, and chromophobic RCC for 14 tumors. With b values of 0 and 500 sec/mm(2), clear cell RCCs showed a significantly higher mean ADC (1.849 × 10(-3) mm(2)/sec) than papillary (1.087 × 10(-3) mm(2)/sec) and chromophobic (1.307 × 10(-3) mm(2)/sec) RCCs (P < .001); however, the difference between papillary and chromophobic RCCs was not significant (P = .068). With b values of 0 and 800 sec/mm(2), clear cell RCC showed the largest mean ADC (1.698 × 10(-3) mm(2)/sec) of the three subtypes, and the difference between each pair of subtypes was significant (P < .001). ADCs obtained with b values of 0 and 800 sec/mm(2) were more effective for distinguishing clear cell from non-clear cell RCC (area under the ROC curve, 0.973): A threshold value of 1.281 × 10(-3) mm(2)/sec permitted distinction with high sensitivity (95.9%) and specificity (94.4%). DW imaging with b values of 0 and 800 sec/mm(2) allows sensitive and specific differentiation of clear cell, papillary, and chromophobic RCCs, suggesting that DW imaging may be useful in the preoperative characterization of RCC.

Diffusion-Weighted Magnetic Resonance Imaging in Evaluation of Gastric Cancer

To investigate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the diagnosis of gastric tumors and discuss the diagnostic importance and potential use of apparent diffusion coefficient (ADC) measurements. Beginning in March 2009, DW-MRI was added to the routine abdominal and pelvic MR examination for all patients imaged at our institution. A total of 21 patients (12 men and 9 women; mean age 55±6.3SD, range: 39-74 years) with known gastric malignancy were referred to our MR unit. All MRI examinations were performed using a 1.5-T MRI scanner (Magnetom Avanto, Siemens Healthcare). The evaluation of the DW-MRI examinations was made by radiologists' consensus. Changes in the signal intensity of the lesions were determined by their appearance in images at b=50, 400, and 800 s/mm(2) and in ADC maps. Results were compared with histopathological findings. All of the gastric tumors in this study showed high signal intensity in DW-MRI and low signal intensity in ADC maps. Mean ADC values for gastric tumor and normal gastric wall were 0.892±0.23 SD mm(2)/s and 1.453±0.35 SD mm(2)/s respectively. The mean ADC values of gastric tumors were significantly lower than that of the normal gastric wall. DW-MRI and ADC values together can successfully differentiate gastric tumors from normal gastric wall.

Apparent diffusion coefficient vale of the brain in patients with Gaucher’s disease type II and type III

The aim of this work is to assess the usefulness of apparent diffusion coefficient (ADC) value of the brain for diagnosis of patients with Gaucher's disease type II and type III. Prospective study was conducted upon 13 patients (nine boys and four girls aged 8 months-14 years: mean 6.1 years) with Gaucher's disease type II and III and for age-matched control group (n = 13). Diffusion-weighted magnetic resonance imaging using a single-shot echo-planar imaging with a diffusion-weighted factor b of 0, 500, and 1,000 s/mm(2) was done for all patients and volunteers. The ADC value was calculated in ten regions of the brain parenchyma and correlated with genotyping. There was significantly lower ADC value of the cortical frontal (P = 0.003), cortical temporal (P = 0.04), frontal subcortical white matter (P = 0.02), corticospinal tract (P = 0.001), cerebellum (P = 0.001), medulla (P = 0.002), and midbrain (P = 0.02) between patients and volunteers. There was significant difference in the ADC value of the frontal and temporal gray matter (P = 0.04 and 0.05, respectively) between patients with heterozygous and homozygous gene mutation. We concluded that ADC value is a new promising quantitative imaging parameter that can be used for the detection of brain abnormalities in patients with Gaucher's disease type II and type III and has a correlation with genotyping.

Renal Masses: Characterization with Diffusion-weighted MR Imaging—A Preliminary Experience

To retrospectively assess the usefulness of apparent diffusion coefficients (ADCs) for characterizing renal masses (ie, viable solid tumors, necrotic or cystic tumor areas, and benign cysts). The institutional review board waived the requirement for informed consent for this retrospective HIPAA-compliant study. The data of 25 consecutive patients (15 men, 10 women; age range, 39-75 years) who underwent renal magnetic resonance (MR) imaging, including diffusion-weighted imaging, before nephrectomy were included. Renal MR examinations were performed by using transverse T1-weighted dual-echo in-phase and out-of-phase sequences and transverse and coronal T2-weighted single-shot fast spin-echo sequences. Three-dimensional fat-saturated T1-weighted dynamic gadopentetate dimeglumine-enhanced sequences also were performed. Precontrast single-shot spin-echo echo-planar diffusion-weighted images were obtained with b values of 0, 500, and 1000 sec/mm(2) at 1.5 T. Regions of interest were placed on renal lesions to measure the ADC of whole lesions, enhancing viable soft tissue, and nonenhancing necrotic or cystic areas. The T1 signal characteristics of the renal lesions and necrotic or cystic areas were recorded. The Wilcoxon rank sum test was used to compare the median ADC values of the various types of lesions and areas. Twenty-six renal tumors were found in the 25 patients. Eight patients were found to have 11 benign cysts. Renal tumors had significantly lower ADCs (median, 189.3 x 10(-5) mm(2)/sec; range, [102.0-262.0] x 10(-5) mm(2)/sec) compared with benign cysts (median, 322.8 x 10(-5) mm(2)/sec; range, [217.0-421.0] x 10(-5) mm(2)/sec; P < .001). Solid enhancing tumors had significantly lower ADCs (median, 162.3 x 10(-5) mm(2)/sec; range, [102.0-284.0] x 10(-5) mm(2)/sec) compared with nonenhancing necrotic or cystic regions (median, 247.7 x 10(-5) mm(2)/sec; range, [85.2-310.0] x 10(-5) mm(2)/sec; P = .007) [corrected]. T1 hyperintense lesions had lower ADCs compared with their hypointense counterparts. The T1 signal characteristics of a renal lesion appear to be related to the ADC of the lesion. ADC may be helpful in characterizing and differentiating renal masses.

Apparent Diffusion Coefficients of Breast Tumors: Clinical Application

To evaluate the usefulness of apparent diffusion coefficient (ADC) for the differential diagnosis of breast tumors and to determine the relation between ADC and tumor cellularity. One hundred and thirty-six female patients (age range, 17-83 years; average age, 51.7 years) with 140 histologically proven breast tumors underwent diffusion-weighted magnetic resonance (MR) imaging (DWI) using the spin-echo echo-planar technique, and the ADCs of the tumors were calculated using 3 different b values, 0, 500, and 1000 s/mm(2). The diagnoses consisted of fibroadenoma (FA, n=16), invasive ductal carcinoma, not otherwise specified (IDC, n=117), medullary carcinoma (ME, n=3) and mucinous carcinoma (MU, n=4). Tumor cellularity was calculated from surgical specimens. The ADCs of breast tumors and cellularity were compared between different histological types by analysis of variance and Scheffe's post hoc test. The correlation between tumor cellularity and ADC was analyzed by Pearson correlation test. Significant differences were observed in ADCs between FA and all types of cancers (P<0.05) and between MU and other types of cancers (P<0.01) and in cellularity between FA and cancers except MU (P<0.01) and between MU and other types of cancers (P<0.01). There was an inverse correlation between ADC and tumor cellularity (P<0.01, r(2)=0.451). The ADC may potentially help in differentiating benign and malignant breast tumors. Tumor ADC correlates inversely with tumor cellularity.

Sulci density map to aid in use of apparent diffusion coefficient for therapy evaluation

In order to more accurately asses variations in the apparent diffusion coefficient used for therapy evaluation, we have studied the variation in sulci density in the human brain. Sagittal, axial and coronal magnetic resonance imaging scans have been analyzed to determine the change of the coefficient of variance of pixel intensity as a function of position. In the sagittal direction, relative to the 50% most medial slices, we find an 11.0%+/-4.8% (S.D.) decrease in the next 25% (12.5% on each side) of the slices. The most lateral 25% of the slices had less of a decrease and more variation: 7.0%+/-12.2%. Similar variations were observed in axial and coronal scans.

Diffusion-Weighted Imaging of the Prostate at 3 T for Differentiation of Malignant and Benign Tissue in Transition and Peripheral Zones

To evaluate prospectively the use of apparent diffusion coefficients (ADCs) for the differentiation of malignant and benign tissue in the transition (TZ) and peripheral (PZ) zones of the prostate diffusion-weighted imaging (DWI) at 3 T magnetic resonance imaging (MRI) using a phased-array coil. The DWI at 3-T MRI was performed on a total of 35 patients before radical prostatectomy. A single-shot echo-planar imaging DWI technique with b = 0 and b = 1000 s/mm2 was used. The ADC values were measured in both benign and malignant tissues in the PZ and TZ using regions of interest. Differences between PZ and TZ ADC values were estimated using a paired Student t test. Presumed ADC cutoff values in the PZ and TZ for the diagnosis of cancer were assessed by receiver operating characteristic analysis. The ADC values of malignant tissues were significantly lower than those of benign tissues in the PZ and TZ (P < 0.001; 1.32 +/- 0.24 x 10(-3) mm2/s vs 1.97 +/- 0.25 x 10(-3) mm2/s, and 1.37 +/- 0.29 x 10(-3) mm2/s vs 1.79 +/- 0.19 x 10(-3) mm2/s, respectively). For tumor diagnosis, cutoff values of 1.67 x 10(-3) mm2/s (PZ) and 1.61 x 10(-3) mm2/s (TZ) resulted in sensitivities and specificities of 94% and 91% and 90% and 84%, respectively. The DWI of the prostate at 3T MRI using a phased-array coil was useful for the differentiation of malignant and benign tissues in the TZ and PZ.

Apparent diffusion coefficient measurements with diffusion‐weighted magnetic resonance imaging for evaluation of hepatic fibrosis

To evaluate the use of apparent diffusion coefficient (ADC) measurements based on diffusion-weighted MRI (DWI) to assess stage of liver disease. A total of 31 patients who underwent both a liver biopsy and DWI and 132 patients who only underwent DWI were enrolled. Biopsy specimens were scored for fibrosis and necroinflammation according to the Knodell histology activity index (HAI). The 31 patients consisted of 21 patients with chronic hepatitis and 10 with cirrhosis (Child-Pugh stage A in nine and stage B in one), and the 132 patients consisted of 56 patients with cirrhosis (Child-Pugh stage A in 41, stage B in 10, and stage C in five), 42 with chronic hepatitis, and 34 with normal liver function. The ADCs in the liver parenchyma were measured using DWI with relatively low b factors (b = 0.01 and 128.01 seconds/mm(2)) and were compared among the HAI scores and among patients with cirrhosis, chronic hepatitis, and normal liver function. The ADCs decreased as the fibrosis score in the HAI increased, and the correlation was statistically significant (P < 0.0001). No relationship between the ADCs and the necroinflammation scores in the HAI was found. The ADCs decreased as the stage of liver disease progressed or as the Child-Pugh stage progressed, and these relationships were statistically significant (P < 0.0001). ADC measurements are potentially useful for the evaluation of fibrosis staging in the liver.

Usefulness of Apparent Diffusion Coefficient in Ovarian Cystic Tumors Using Diffusion-Weighted Magnetic Resonance Imaging

Purpose: To evaluate the usefulness of apparent diffusion coefficient (ADC) values using diffusion-weighted magnetic resonance imaging (DWI) in patients with ovarian cystic tumors. Materials and Methods: During past 12 months, we studied 30 patients who were clinically suspected of having ovarian cystic tumors and who underwent DWI using a 1.5 T MR unit. Eight patients with small cystic ovarian lesions of less than 3 cm in diameter and insufficient DWI were excluded from the calculation of the ADC values. The remaining twenty-six cystic ovarian lesions in 22 patients were classified into four groups; ovarian cysts, cystadenomas, other benign tumors, and malignant tumors. DWI was obtained using single-shot spin echo planar imaging and two gradient steps (b values of 0, 800 sec/). The ADC values were measured using regions-of-interest (ROI) in the cystic components of the DWI located in the same section as the T2- weighted image and away from the septation and solid components. Results: The mean ADC values were 0.1960.10510-3 /sec in the ovarian cysts, 1.3121.06410-3 /sec in the cystadenomas, 0.2740.12410-3 /sec in the other benign tumors, and 1.0110.08010-3 /sec in the malignant tumors. The differences in the ADC values between the ovarian cysts and cystadenomas, the ovarian cysts and malignant tumors, the cystadenomas and other benign tumors, and the other benign tumors and malignant tumors were statistically significant (p 0.05). Conclusion: The calculated ADC values using DWI should be helpful in the differential diagnosis of cystic ovarian tumors.