Diffusion-weighted MR imaging of uterine leiomyomas following uterine artery embolization.

PURPOSE: To test whether variations in apparent diffusion coefficient (ADC) values of uterine leiomyomas after uterine artery embolization (UAE) may correlate with outcome and assess the effects of UAE on leiomyomas and normal myometrium with magnetic resonance imaging (MRI). METHODS: Data of 49 women who underwent pelvic MRI before and after UAE were retrospectively reviewed. Uterine and leiomyoma volumes, ADC values of leiomyomas, and normal myometrium were calculated before and after UAE. RESULTS: By comparison with baseline ADC values, a significant drop in leiomyoma ADC was found at 6-month post-UAE (1.096 × 10(-3) mm(2)/s vs. 0.712 × 10(-3) mm(2)/s, respectively; p < 0.0001), but not at 48-h post-UAE. Leiomyoma devascularization was complete in 40/49 women (82 %) at 48 h and in 37/49 women (76 %) at 6 months. Volume reduction and leiomyoma ADC values at 6 months correlated with the degree of devascularization. There was a significant drop in myometrium ADC after UAE. Perfusion defect of the myometrium was observed at 48 h in 14/49 women (28.5 %) in association with higher degrees of leiomyoma devascularization. CONCLUSION: Six months after UAE, drop in leiomyoma ADC values and volume reduction correlate with the degree of leiomyoma devascularization. UAE affects the myometrium as evidenced by a drop in ADC values and initial myometrial perfusion defect. KEY POINTS: • A drop in leiomyoma ADC values is observed 6 months after UAE. • Drop in leiomyoma ADC value is associated with leiomyoma devascularizarion after UAE. • MR 48 h post-UAE allows assessing leiomyoma devascularization. • Myometrium perfusion defect occurs more often in women with a smaller uterus.

Diffusion-weighted MR imaging for the diagnosis of abscess complicating fistula-in-ano: preliminary experience.

OBJECTIVE: To investigate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of abscess-complicating fistula-in-ano. METHODS: This retrospective study was approved by our Institutional Review Board and informed consent was waived. MRI examinations, including fat-suppressed T2-weighted turbo spin-echo (T2-TSE) MRI and DWMRI, of 24 patients with a fistula-in-ano, were reviewed by two independent readers for the presence and number of visible fistulas, conspicuity and apparent diffusion coefficient (ADC) measurement of suspected fistula tracks and pelvic collections. The reference standard was surgical with follow-up findings. RESULTS: Sensitivity was 91.2 % [95 % CI: 76 %-98 %] for T2-weighted TSE MRI and 100 % [95 % CI: 90 %-100 %] for DWMRI detecting fistulas. ADC values were lower in abscesses than in inflammatory masses (P = 0.714.10(-6)). The area under the ROC curve was 0.971 and the optimal cut-off ADC value was 1.186 × 10(-3) mm(2)/s, yielding a sensitivity of 100 % [95 % CI: 77 %-100 %], a specificity of 90 % [95 % CI: 66 %-100 %], a positive predictive value of 93 % [95 % CI: 82.8 %-100 %] and a negative predictive value of 90 % [95 % CI: 78 %-100 %] for an abscess diagnosis. Fistula conspicuity was greater with DWMRI than with T2-TSE MRI for the two observers (P = 0.0034 and P = 0.0007). CONCLUSION: DWMRI shows high sensitivity and specificity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass. Conspicuity of fistulas-in-ano is greater with DWMRI than with T2-weighted TSE MRI. KEY POINTS: • DWMRI can differentiate between pelvic abscess and inflammatory mass. • DWMRI helps avoid gadolinium-chelate administration in patients with a suspected fistula-in-ano. • DWMRI provides high degrees of conspicuity for fistula-in-ano. • Conspicuity of fistulas is better with DWMRI imaging than with T2-TSE-weighted MRI.

Peroxynitrite activity of hemin-functionalized reduced graphene oxide.

Conducting interfaces modified with reduced graphene oxide (rGO) have shown improved electrochemical response for different analytes. The efficient formation of functionalized rGO based materials is thus of current interest for the development of sensitive and selective biosensors. Herein, we report a simple and environmentally friendly method for the formation of a hemin-functionalized rGO hybrid nanomaterial that exhibits remarkable sensitivity to peroxynitrite (ONOO(-)) in solution. The hemin-functionalized rGO hybrid nanomaterial was formed by mixing an aqueous solution of graphene oxide (GO) with hemin and sonicating the suspension for 5 h at room temperature. In addition to playing a key role in biochemical and electrocatalytic reactions, hemin has been proven to be a good reducing agent for GO. The sensitivity of the peroxynitrite sensor is ≈7.5 ± 1.5 nA mM(-1) with a detection limit of 5 ± 1.5 nM.