Feasibility of Computed Diffusion Weighted Imaging and Optimization of b-value in Cervical Cancer

Abstract

Purpose:To evaluate the feasibility of computed diffusion weighted imaging (DWI) in cervical cancer and investigate the optimal b-value using computed DWI.Methods:The present retrospective study involved 85 patients with cervical cancer in the International Federation of Gynecology and Obstetrics (FIGO) stage IB, IIA or IIB. DWI was obtained with b-values of 0, 100, 500 and 1000 s/mm2. Computed DWI with b-values of 800, 1000, 1300, 1600 and 2000 s/mm2 (cDWI800, cDWI1000, cDWI1300, cDWI1600, cDWI2000) were generated from all measured DWI (mDWI) data. Qualitatively, computed DWI was evaluated in terms of tumor conspicuity, signal suppression of the fat in the imaged area and total image quality by two radiologists independently with reference to mDWI with b-value of 1000 s/mm2. The b-value at which the signal of the endocervical canal was suppressed was recorded. Quantitatively, the signal intensities of tumor, myometrium, endocervical canal, endometrium, and gluteal subcutaneous fat were measured and represented as contrast ratios (CR).Results:Regarding tumor conspicuity and total image quality, significantly higher scores were obtained at cDWI1300 and cDWI1600 compared to the others (post-hoc comparison, P < 0.001), except for the total image quality between cDWI1000 and cDWI1600 in one reader. Signal suppression of the fat was the worst at cDWI2000. The signal intensity of the endocervical canal was suppressed in 24/27 cases on cDWI1600 and in 26/27 cases on cDWI2000. The CRs of tumor to myometrium, cervix, and endometrium increased with higher b-values, while the CRs of tumor to fat decreased and were statistically significant (post-hoc comparison, P < 0.001).Conclusion:Computed DWI with the b-values of 1300 and 1600 would be suitable for the evaluation of cervical cancer due to good tumor conspicuity.

Diffusion‐Weighted MRI of Breast Cancer: Improved Lesion Visibility and Image Quality Using Synthetic b‐Values

“…Different b‐values for breast DWI have been compared by O'Flynn et al; however, in their study only images from b‐values of 1500 and 2000 s/mm 2 were calculated and these performed equally in terms of image quality . Lesion visibility and image quality were rated best at intermediate b‐values (1300 and 1600 s/mm 2 ) in a study on cervical cancer, while in the prostate, optimal b‐values were reported to range between 1500–2500 s/mm 2 , and 2000–3000, respectively …”

“…Accordingly, the results of this study, as well as those of a phantom study published in 2011, show that this is also true for calculated b‐values: tissue SI will decrease heavily with increasing b‐values; diffusion‐restricted, water‐containing tumors such as most breast cancers will lose less signal; and background noise will increase. Similar results using calculated b‐values have been reported, eg, in cervical cancer …”

“…In the case of this study, inter‐ and intrareader agreement was generally moderate to good concerning lesion visibility and image quality. While, to our knowledge, no comparable data are available for breast tumors, these results are similar to those reported by Moribata et al, who found good agreement for lesion conspicuity using calculated b‐values in cervical cancer . The agreement was, however, poor concerning acceptable and preferred b‐values.…”

Feasibility and Diagnostic Performance of Voxelwise Computed Diffusion‐Weighted Imaging in Breast Cancer

“…Computed DWI (cDWI) is a mathematical computation method that generates higher b‐value DWIs from images acquired with lower b‐values . It was reported that cDWI could obtain good image quality and a high contrast‐to‐noise ratio (CNR) by suppressing background signal and, thus, might increase lesion conspicuity . In the detection of breast cancer, it has been shown that cDWI with a higher b‐value has the potential to improve diagnostic sensitivity .…”

“…10 It was reported that cDWI could obtain good image quality and a high contrast-to-noise ratio (CNR) by suppressing background signal and, thus, might increase lesion conspicuity. [11][12][13][14] In the detection of breast cancer, it has been shown that cDWI with a higher bvalue has the potential to improve diagnostic sensitivity. 15 However, as b-value increases, the signal intensity decreases in all tissues.…”