Apparent diffusion coefficient (ADC) measurements in pancreatic adenocarcinoma: A preliminary study of the effect of region of interest on ADC values and interobserver variability

Objective: To determine whether the apparent diffusion coefficient (ADC) value obtained by diffusion-weighted magnetic resonance imaging (DW-MRI) can be used as a reliable detector of response of carcinoma of the cervix treated with chemoradiotherapy, compared with conventional T2-weighted MRI.Design: A prospective cohort study was performed.Setting: Department of Oncology, Universitas-National Hospital Complex, Bloemfontein.Subjects: Seventeen women with advanced cervical cancer, FIGO staging IIB - IVB, were selected for chemoradiation.Outcome measures: Patients underwent pelvic MRI before therapy, 14 days after onset of therapy, and in the last week of treatment (5th/6th week). Axial and sagittal conventional T2 was followed by DW-MRI in the axial plane from which a tumour region of interest (ROI) was manually drawn to calculate ADC values using b-values of 500 and 1 000 s/mm2.Results: ADC values for cervical carcinoma increased after treatment with chemoradiation. The most significant observation was seen 14 days after treatment was started. The mean ADC value increased with 20% (b=500 s/mm2) and 24% (b=1 000 s/mm2) (statistically significant, p<0.05) compared with a decrease in tumour size of only 8%, which was not statistically significant (p=0.075). Responders showed a larger change in ADC values than non-responders.Conclusion: The study showed considerable promise in the ability of ADC to identify early tumour response to therapy. DW-MRI is a non-invasive functional imaging technique that may in future change management in oncology by early identification of non-responders, hence avoiding unnecessary treatment.

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Apparent diffusion coefficient measurement in glioma: Influence of region-of-interest determination methods on apparent diffusion coefficient values, interobserver variability, time efficiency, and diagnostic ability

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.25405 ◽

2016 ◽

Vol 45 (3) ◽

pp. 722-730 ◽

Cited By ~ 21

Author(s):

Xu Han ◽

Shiteng Suo ◽

Yawen Sun ◽

Jinyan Zu ◽

Jianxun Qu ◽

...

Keyword(s):

Diffusion Coefficient ◽

Apparent Diffusion Coefficient ◽

Interobserver Variability ◽

Region Of Interest ◽

Diagnostic Ability ◽

Time Efficiency ◽

Apparent Diffusion Coefficient Values ◽

Apparent Diffusion ◽

Coefficient Measurement ◽

Determination Methods

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Diffusion tensor imaging reveals microstructural differences between subtypes of trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2019.4.jns19299 ◽

2020 ◽

Vol 133 (2) ◽

pp. 573-579 ◽

Cited By ~ 1

Author(s):

Matthew S. Willsey ◽

Kelly L. Collins ◽

Erin C. Conrad ◽

Heather A. Chubb ◽

Parag G. Patil

Keyword(s):

Diffusion Coefficient ◽

Diffusion Tensor Imaging ◽

Trigeminal Neuralgia ◽

Apparent Diffusion Coefficient ◽

Diffusion Tensor ◽

Statistical Significance ◽

Region Of Interest ◽

Pain Syndrome ◽

Radial Diffusivity ◽

Apparent Diffusion

OBJECTIVETrigeminal neuralgia (TN) is an uncommon idiopathic facial pain syndrome. To assist in diagnosis, treatment, and research, TN is often classified as type 1 (TN1) when pain is primarily paroxysmal and episodic or type 2 (TN2) when pain is primarily constant in character. Recently, diffusion tensor imaging (DTI) has revealed microstructural changes in the symptomatic trigeminal root and root entry zone of patients with unilateral TN. In this study, the authors explored the differences in DTI parameters between subcategories of TN, specifically TN1 and TN2, in the pontine segment of the trigeminal tract.METHODSThe authors enrolled 8 patients with unilateral TN1, 7 patients with unilateral TN2, and 23 asymptomatic controls. Patients underwent DTI with parameter measurements in a region of interest within the pontine segment of the trigeminal tract. DTI parameters were compared between groups.RESULTSIn the pontine segment, the radial diffusivity (p = 0.0049) and apparent diffusion coefficient (p = 0.023) values in TN1 patients were increased compared to the values in TN2 patients and controls. The DTI measures in TN2 were not statistically significant from those in controls. When comparing the symptomatic to asymptomatic sides in TN1 patients, radial diffusivity was increased (p = 0.025) and fractional anisotropy was decreased (p = 0.044) in the symptomatic sides. The apparent diffusion coefficient was increased, with a trend toward statistical significance (p = 0.066).CONCLUSIONSNoninvasive DTI analysis of patients with TN may lead to improved diagnosis of TN subtypes (e.g., TN1 and TN2) and improve patient selection for surgical intervention. DTI measurements may also provide insights into prognosis after intervention, as TN1 patients are known to have better surgical outcomes than TN2 patients.

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Apparent diffusion coefficient cannot discriminate metastatic and non-metastatic lymph nodes in rectal cancer: a meta-analysis

International Journal of Colorectal Disease ◽

10.1007/s00384-021-03986-8 ◽

2021 ◽

Author(s):

Alexey Surov ◽

Hans-Jonas Meyer ◽

Maciej Pech ◽

Maciej Powerski ◽

Jasan Omari ◽

...

Keyword(s):

Rectal Cancer ◽

Diffusion Coefficient ◽

Apparent Diffusion Coefficient ◽

Lymph Nodes ◽

Meta Analysis ◽

Adc Value ◽

Metastatic Lymph Nodes ◽

Metastatic Lymph ◽

Apparent Diffusion ◽

Adc Values

Abstract Background Our aim was to provide data regarding use of diffusion-weighted imaging (DWI) for distinguishing metastatic and non-metastatic lymph nodes (LN) in rectal cancer. Methods MEDLINE library, EMBASE, and SCOPUS database were screened for associations between DWI and metastatic and non-metastatic LN in rectal cancer up to February 2021. Overall, 9 studies were included into the analysis. Number, mean value, and standard deviation of DWI parameters including apparent diffusion coefficient (ADC) values of metastatic and non-metastatic LN were extracted from the literature. The methodological quality of the studies was investigated according to the QUADAS-2 assessment. The meta-analysis was undertaken by using RevMan 5.3 software. DerSimonian, and Laird random-effects models with inverse-variance weights were used to account the heterogeneity between the studies. Mean DWI values including 95% confidence intervals were calculated for metastatic and non-metastatic LN. Results ADC values were reported for 1376 LN, 623 (45.3%) metastatic LN, and 754 (54.7%) non-metastatic LN. The calculated mean ADC value (× 10−3 mm2/s) of metastatic LN was 1.05, 95%CI (0.94, 1.15). The calculated mean ADC value of the non-metastatic LN was 1.17, 95%CI (1.01, 1.33). The calculated sensitivity and specificity were 0.81, 95%CI (0.74, 0.89) and 0.67, 95%CI (0.54, 0.79). Conclusion No reliable ADC threshold can be recommended for distinguishing of metastatic and non-metastatic LN in rectal cancer.

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