scholarly journals Synthetic Apparent Diffusion Coefficient for High b-Value Diffusion-Weighted MRI in Prostate

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Prativa Sahoo ◽  
Russell C. Rockne ◽  
Alexander Jung ◽  
Pradeep K Gupta ◽  
Ram K. S. Rathore ◽  
...  

Purpose. It has been reported that diffusion-weighted imaging (DWI) with ultrahigh b-value increases the diagnostic power of prostate cancer. DWI with higher b-values is challenging as it commonly suffers from low signal-to-noise ratio (SNR), distortion, and longer scan time. The aim of our study was to develop a technique for quantification of apparent diffusion coefficient (ADC) for higher b-values from lower b-value DW images. Materials and Methods. Fifteen patients (7 malignant and 8 benign) were included in this study retrospectively with the institutional ethical committee approval. All images were acquired at a 3T MR scanner. The ADC values were calculated using a monoexponential model. Synthetic ADC (sADC) for higher b-value was computed using a log-linear model. Contrast ratio (CR) between prostate lesion and normal tissue on synthetic DWI (sDWI) was computed and compared with original DWI and ADC images. Results. No significant difference was observed between actual ADC and sADC for b-2000 in all prostate lesions. However, CR increased significantly (p=0.002, paired t-test) in sDWI as compared to DWI. Malignant lesions showed significantly lower sADC as compared to benign lesions (p=0.0116, independent t-test). Mean (±standard deviation) of sADC of malignant lesions was 0.601 ± 0.06 and for benign lesions was 0.92 ± 0.09 (10−3 mm2/s). Discussion/Conclusion. Our initial investigation suggests that the ADC values corresponding to higher b-value can be computed using log-linear relationship derived from lower b-values (b ≤ 1000). Our method might help clinicians to decide the optimal b-value for prostate lesion identification.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sherif Abugamra ◽  
Aya Yassin ◽  
Asmaa Saber Mostafa Abdel-Rehim ◽  
Dina Sayed Sheha

Abstract Background The aim of this study was to prospectively evaluate the role of diffusion weight MRI (DWI) in the characterization of hepatic focal lesions by using apparent diffusion coefficient (ADC). Thirty patients (18 women, 12 men; mean age 48.5 years) with hepatic focal lesions were included in this study. Patients underwent DW MR imaging with the SPLICE sequence. ADC of each focal lesion carcinoma was calculated from DW MR Images obtained with low and high b values. ADCs were compared among pathological types of focal lesions. Results Among the 30 patients included in the study, 46 focal lesions were detected. Twenty-four lesions were metastatic lesions from primary cancer, 7 lesions were hepatocellular carcinoma (HCC), 9 lesions were hemangiomas, and 6 lesions were simple cysts. There was highly significant difference between the mean ADC of the malignant lesions (metastasis and HCC) and the mean ADC of benign lesions (hemangiomas and cysts). The ADC of malignant lesion was much less than that of benign lesion. The mean ADC of malignant lesions (n = 31) was 0.73 ± 0.19 × 10−3 mm2/s, and the mean ADC of benign lesions (n = 15) was 1.94 ± 0.68 × 10−3 mm2/s (p value < 0.001). There was no significant difference between the cysts and hemangiomas. There was no statistically significant difference between the metastases and hepatocellular carcinoma. Conclusion ADCs values were able to differentiate benign from malignant lesions. ADC should be considered in the work up of patients with hepatic focal lesions.


2019 ◽  
Author(s):  
Prativa Sahoo ◽  
Russell Rockne ◽  
Jung Alexander ◽  
Pradeep K Gupta ◽  
Rakesh K Gupta

AbstractPurposeIt has been reported that diffusion weighted imaging (DWI) with ultrahigh b-value increases the diagnostic power of prostate cancer. DWI imaging with higher b-values is challenging as it commonly suffers from low signal to noise ratio (SNR), distortion and longer scan time. The aim of our study was to develop a technique for quantification of apparent diffusion coefficient (ADC) for higher b-values from lower b-value DW images.Materials and MethodsFifteen patient (7 malignant, 8 benign) with prostate cancer were included in this study retrospectively with the institutional ethical committee approval. All images were acquired at 3T MR scanner. The ADC values were calculated using mono-exponential model. Synthetic ADC (sADC) for higher b-value were computed using a log-linear model. Contrast ratio (CR) between prostate lesion and normal tissue on synthetic DWI (sDWI) was computed and compared with original DWI and ADC images.ResultsNo significant difference was observed between actual ADC and sADC for b-2000 in all prostate lesions. However; CR increased significantly (p=0.002, paired t-test) in sDWI as compared to DWI. Malignant lesions showed significantly lower sADC as compared to benign lesion (p=0.0116, independent t-test). Mean (±standard deviation) of sADC of malignant lesions was 0.601±0.06 and for benign lesions was 0.92 ± 0.09 (10−3mm2/s).Discussion / ConclusionOur initial investigation suggests that the ADC values corresponding to higher b-value can be computed using log-linear relationship derived from lower b-values (b≤1000). Our method might help clinician to decide the optimal b-value for prostate lesion identification.


QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
K A A Sabry ◽  
O F Kamel ◽  
A Y Ahmed ◽  
H M Abuzeid

Abstract Purpose to assess the role of Diffusion-weighted MRI in diagnosis of acute pancreatitis by measure the apparent diffusion coefficient (ADC) values detected by diffusion-weighted imaging (DWI) in acute pancreatitis and compare them with the control group Methods and Material sixteen patients with acute pancreatitis and sixteen normal controls underwent DWI with b values (0,200 & 800). Apparent diffusion coefficient (ADC) maps are generated from DWI and ADC values were calculated for pancreas and compared the results between the two groups Results The mean pancreatic ADC in the AP group (1.17 × 10(-3) mm(2)/s ± 0.2) was significantly lower than in the normal group (1.6 × 10(-3) mm(2)/s ± 0.32). There was no significant difference in mean ADCs between each of the pancreatic segments in the controls. A threshold ADC value of 1.38 × 10-3 mm(2)/s yielded a sensitivity of 93% and specificity of 87% for detecting acute pancreatitis. Pancreatic ADCs are significantly lower in patients with AP than normal controls. Conclusion MR diffusion imaging could be an important supportive tool in diagnosis of acute pancreatitis


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247301
Author(s):  
Jelena Djokić Kovač ◽  
Marko Daković ◽  
Aleksandra Janković ◽  
Milica Mitrović ◽  
Vladimir Dugalić ◽  
...  

Background The utility of intravoxel incoherent motion (IVIM) related parameters in differentiation of hypovascular liver lesions is still unknown. Purpose The purpose of this study was to evaluate the value of IVIM related parameters in comparison to apparent diffusion coefficient (ADC) for differentiation among intrahepatic mass-forming cholangiocarcinoma (IMC), and hypovascular liver metastases (HLM). Methods Seventy-four prospectively enrolled patients (21 IMC, and 53 HLM) underwent 1.5T magnetic resonance examination with IVIM diffusion-weighted imaging using seven b values (0–800 s/mm2). Two independent readers performed quantitative analysis of IVIM-related parameters and ADC. Interobserver reliability was tested using a intraclass correlation coefficient. ADC, true diffusion coefficient (D), perfusion-related diffusion coefficient (D*), and perfusion fraction (ƒ) were compared among the lesions using Kruskal-Wallis H test. The diagnostic accuracy of each parameter was assessed by receiver operating characteristic (ROC) curve analysis. Results The interobserver agreement was good for ADC (0.802), and excellent for D, D*, and ƒ (0.911, 0.927, and 0.942, respectively). ADC, and D values were significantly different among IMC and HLM (both p < 0.05), while there was no significant difference among these lesions for ƒ and D* (p = 0.101, and p = 0.612, respectively). ROC analysis showed higher diagnostic performance of D in comparison to ADC (AUC = 0.879 vs 0.821). Conclusion IVIM-derived parameters in particular D, in addition to ADC, could help in differentiation between most common hypovascular malignant liver lesions, intrahepatic mass—forming cholangiocarcinoma and hypovascular liver metastases.


Author(s):  
Nada Gamal El-Husseiny ◽  
Sayed Mohamed Mehana ◽  
Sherif Farouk El Zawawy

Abstract Background Colorectal cancer is considered one of the most common causes of cancer-related deaths worldwide. We aim to evaluate the efficacy of DWI-MRI in predicting response to chemotherapy in this cohort. The study included 30 lesions in 20 biopsy proven-colorectal cancer patients with hepatic metastasis larger than 1 cm. All patients underwent both triphasic CT with intravenous contrast, pre-chemotherapy MRI (axial T2 and DW sequences) which was repeated 21 days following chemotherapy. A follow-up CT was done 2 months later. The response of the lesions was evaluated using the RESCIST criteria. On MRI, the lesions corresponding to the ones chosen on CT were identified and the apparent diffusion coefficient (ADC) values of pre- and post-chemotherapy images were recorded and correlated with the CT results. Results In the study, 17 (56.7%) of the lesions showed response to chemotherapy while 13 (43.3%) were non-responding. There was no significant difference in pretreatment ADC values between responding and non-responding lesions (p = 0.14). The mean percentage increase in ADC values in responding lesions was 42% compared to 18% in non-responding lesions (p < 0.001). Lesions that showed less than 18% increase were all found to be non-responsive Conclusion DWI-MRI has an emerging role in early assessment of early treatment response that can be detected before morphological response for patients with hepatic metastasis from colorectal cancer. Based on our study, the use of 25 % as the cutoff point of percent difference in ADC for detection of non-responding lesions proved to be successful only 21 days after the 1st chemotherapy cycle.


2017 ◽  
Vol 59 (8) ◽  
pp. 902-908
Author(s):  
Valentina Cipolla ◽  
Daniele Guerrieri ◽  
Giacomo Bonito ◽  
Simone Celsa ◽  
Carlo de Felice

Background The effect of gadolinium-based contrast agents on diffusion-weighted imaging (DWI) measurements of breast lesions is still not clear. Purpose To investigate gadolinium effects on DWI and apparent diffusion coefficient (ADC) in breast lesions and normal parenchyma with 3 Tesla contrast-enhanced MRI. Material and Methods Pre- and post-contrast DWI (b = 0 and b = 1000 s/mm2) were acquired in 47 patients. Measured ADC values, pre- and post-contrast T2 signal intensity (T2 SI) and contrast-to-noise ratio (CNR) were compared with Wilcoxon signed-rank and rank-sum test ( P < 0.05). Results Post-contrast ADC was reduced only in malignant lesions (−34%), T2 SI was reduced both in malignant (−50%) and benign (−36%) lesions. Post-contrast CNR was reduced in all groups except for benign lesions. Conclusion Gadolinium-based contrast agent causes a significant reduction in ADC values of malignant breast lesions.


Author(s):  
Anu Sarah Easo ◽  
Rajeev Anand ◽  
Mini Issac

Background: To determine whether diffusion-weighted imaging (DWI) with measurement of apparent diffusion coefficient (ADC) will help in differentiating endometrial cancer from normal endometrium and to determine whether the grades of endometrial cancer will show significant difference in ADC values.Methods: This is a retrospective study done in MOSC medical college hospital Kolencherry. on patients on whom preoperative MRI was done before hysterectomy. Cases from July 2017 to March 2021 were included. Study cases included 40 females with pathologically confirmed endometrial cancer and 30 females with pathologically proven normal endometrium in cases of uterine leiomyoma and cervical cancer. The exclusion criteria for the study were patients with endometrial cancer in whom surgery was not done within 2 weeks of MRI, patients who were treated with chemotherapy or radiotherapy before surgery, patients who had hydrometra or pyometra.Results: The mean ADC value (10−3 mm2/second) of endometrial cancer was 0.77±0.04, which was significantly lower (p<0.05) than that of normal endometrium (1.323±0.05). The ADC values of different grades of endometrial cancers did not show any statistically significant difference (p>0.05).Conclusions: Our study showed that ADC measurement can differentiate between normal endometrium and endometrial cancer. The ADC values of different grades of endometrial cancers did not show any statistically significant difference.  


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