ABSTRACT
Objective@#It is uncertain why a b-value range of 1500–2000 s/mm2 is optimal. This study was aimed at qualitatively and quantitatively analyzing the optimal b-value range of synthetic diffusion-weighted imaging (sDWI) for evaluating prostatic index lesions. @*Materials and Methods@#This retrospective study included 92 patients who underwent DWI and targeted biopsy for magnetic resonance imaging (MRI)-suggested index lesions. We generated sDWI at a b-value range of 1000–3000 s/mm2 using dedicated software and true DWI data at b-values of 0, 100, and 1000 s/mm2 . We hypothesized that lesion conspicuity would be best when the background (i.e., MRI-suggested benign prostatic [bP] and periprostatic [pP] regions) signal intensity (SI) is suppressed and becomes homogeneous. To prove this hypothesis, we performed both qualitative and quantitative analyses.For qualitative analysis, two independent readers analyzed the b-value showing the best visual conspicuity of an MRIsuggested index lesion. For quantitative analysis, the readers assessed the b-value showing the same bP and pP region SI.The 95% confidence interval (CI) or interquartile range of qualitatively and quantitatively selected optimal b-values was assessed, and the mean difference between qualitatively and quantitatively selected b-values was investigated. @*Results@#The 95% CIs of optimal b-values from qualitative and quantitative analyses were 1761–1805 s/mm2 and 1640– 1771 s/mm2 (median, 1790 s/mm2 vs. 1705 s/mm2 ; p = 0.003) for reader 1, and 1835–1895 s/mm2 and 1705–1841 s/mm2 (median, 1872 s/mm2 vs. 1763 s/mm2 ; p = 0.022) for reader 2, respectively. Interquartile ranges of qualitatively and quantitatively selected optimal b-values were 1735–1873 s/mm2 and 1573–1867 s/mm2 for reader 1, and 1775–1945 s/mm2 and 1591–1955 s/mm2 for reader 2, respectively. Bland-Altman plots consistently demonstrated a mean difference of less than 100 s/mm2 between qualitatively and quantitatively selected optimal b-values. @*Conclusion@#b-value range showing a homogeneous background signal may be optimal for evaluating prostatic index lesions on sDWI. Our qualitative and quantitative data consistently recommend b-values of 1500–2000 s/mm2 .
ABSTRACT
Purpose@#To evaluate the accuracy of magnetic resonance imaging (MRI)-guided breast biopsy. @*Methods@#We retrospectively reviewed the clinical data of 111 consecutive patients referred for MRI-guided breast biopsy after mammography and breast ultrasound between May 2009 and April 2019. After excluding 37 patients without follow-up images (> 2 years), 74 patients (74 lesions) were finally included. We reviewed the histologic results of MRI-guided biopsy and subsequent surgery, post-biopsy management, and breast cancer development during followup. We investigated the false-negative rate, ductal carcinoma in situ (DCIS) underestimation, atypical ductal hyperplasia (ADH) underestimation rate, and technical failure rate of MRIguided biopsy. @*Results@#Among 74 scheduled MRI-guided biopsies, six were canceled because biopsy was deemed unnecessary, while three failed due to technical difficulties (technical failure rate:3/68, 4.4%). MRI-guided biopsy was performed in 65 patients, of which 18 patients were diagnosed with malignant lesions, 46 with benign lesions, and one with ADH bordering on DCIS. Subsequent surgery (n = 27) showed DCIS underestimation in three cases (3/7, 43%), ADH underestimation in two cases (1/2, 50%), as well as seven concordant benign and 11 concordant malignant lesions. The overall false-negative rate was 4.3% (2/46). Thirty-eight out of 48 benign lesions were followed-up (median period, 5.8 years; interquartile range, 4.1 years) without subsequent surgery. Thirty-seven concordant benign lesions were stable (n = 27) or disappeared (n = 10); however, the size of one discordant benign lesion increased on follow-up MRI and it was diagnosed as DCIS after 1 year. @*Conclusion@#MRI-guided biopsy is an accurate method for exclusion of malignancy with a very low false-negative rate.
ABSTRACT
Objective@#It is uncertain why a b-value range of 1500–2000 s/mm2 is optimal. This study was aimed at qualitatively and quantitatively analyzing the optimal b-value range of synthetic diffusion-weighted imaging (sDWI) for evaluating prostatic index lesions. @*Materials and Methods@#This retrospective study included 92 patients who underwent DWI and targeted biopsy for magnetic resonance imaging (MRI)-suggested index lesions. We generated sDWI at a b-value range of 1000–3000 s/mm2 using dedicated software and true DWI data at b-values of 0, 100, and 1000 s/mm2 . We hypothesized that lesion conspicuity would be best when the background (i.e., MRI-suggested benign prostatic [bP] and periprostatic [pP] regions) signal intensity (SI) is suppressed and becomes homogeneous. To prove this hypothesis, we performed both qualitative and quantitative analyses.For qualitative analysis, two independent readers analyzed the b-value showing the best visual conspicuity of an MRIsuggested index lesion. For quantitative analysis, the readers assessed the b-value showing the same bP and pP region SI.The 95% confidence interval (CI) or interquartile range of qualitatively and quantitatively selected optimal b-values was assessed, and the mean difference between qualitatively and quantitatively selected b-values was investigated. @*Results@#The 95% CIs of optimal b-values from qualitative and quantitative analyses were 1761–1805 s/mm2 and 1640– 1771 s/mm2 (median, 1790 s/mm2 vs. 1705 s/mm2 ; p = 0.003) for reader 1, and 1835–1895 s/mm2 and 1705–1841 s/mm2 (median, 1872 s/mm2 vs. 1763 s/mm2 ; p = 0.022) for reader 2, respectively. Interquartile ranges of qualitatively and quantitatively selected optimal b-values were 1735–1873 s/mm2 and 1573–1867 s/mm2 for reader 1, and 1775–1945 s/mm2 and 1591–1955 s/mm2 for reader 2, respectively. Bland-Altman plots consistently demonstrated a mean difference of less than 100 s/mm2 between qualitatively and quantitatively selected optimal b-values. @*Conclusion@#b-value range showing a homogeneous background signal may be optimal for evaluating prostatic index lesions on sDWI. Our qualitative and quantitative data consistently recommend b-values of 1500–2000 s/mm2 .
ABSTRACT
Purpose@#To evaluate the accuracy of magnetic resonance imaging (MRI)-guided breast biopsy. @*Methods@#We retrospectively reviewed the clinical data of 111 consecutive patients referred for MRI-guided breast biopsy after mammography and breast ultrasound between May 2009 and April 2019. After excluding 37 patients without follow-up images (> 2 years), 74 patients (74 lesions) were finally included. We reviewed the histologic results of MRI-guided biopsy and subsequent surgery, post-biopsy management, and breast cancer development during followup. We investigated the false-negative rate, ductal carcinoma in situ (DCIS) underestimation, atypical ductal hyperplasia (ADH) underestimation rate, and technical failure rate of MRIguided biopsy. @*Results@#Among 74 scheduled MRI-guided biopsies, six were canceled because biopsy was deemed unnecessary, while three failed due to technical difficulties (technical failure rate:3/68, 4.4%). MRI-guided biopsy was performed in 65 patients, of which 18 patients were diagnosed with malignant lesions, 46 with benign lesions, and one with ADH bordering on DCIS. Subsequent surgery (n = 27) showed DCIS underestimation in three cases (3/7, 43%), ADH underestimation in two cases (1/2, 50%), as well as seven concordant benign and 11 concordant malignant lesions. The overall false-negative rate was 4.3% (2/46). Thirty-eight out of 48 benign lesions were followed-up (median period, 5.8 years; interquartile range, 4.1 years) without subsequent surgery. Thirty-seven concordant benign lesions were stable (n = 27) or disappeared (n = 10); however, the size of one discordant benign lesion increased on follow-up MRI and it was diagnosed as DCIS after 1 year. @*Conclusion@#MRI-guided biopsy is an accurate method for exclusion of malignancy with a very low false-negative rate.