Assessment of Response to Neoadjuvant Systemic Treatment in Triple-Negative Breast Cancer Using Functional Tumor Volumes from Longitudinal Dynamic Contrast-Enhanced MRI.

Early assessment of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) is critical for patient care in order to avoid the unnecessary toxicity of an ineffective treatment. We assessed functional tumor volumes (FTVs) from dynamic contrast-enhanced (DCE) MRI after 2 cycles (C2) and 4 cycles (C4) of NAST as predictors of response in TNBC. A group of 100 patients with stage I-III TNBC who underwent DCE MRI at baseline, C2, and C4 were included in this study. Tumors were segmented on DCE images of 1 min and 2.5 min post-injection. FTVs were measured using the optimized percentage enhancement (PE) and signal enhancement ratio (SER) thresholds. The Mann-Whitney test was used to compare the performance of the FTVs at C2 and C4. Of the 100 patients, 49 (49%) had a pathologic complete response (pCR) and 51 (51%) had a non-pCR. The maximum area under the receiving operating characteristic curve (AUC) for predicting the treatment response was 0.84 (p < 0.001) for FTV at C4 followed by FTV at C2 (AUC = 0.82, p < 0.001). The FTV measured at baseline was not able to discriminate pCR from non-pCR. FTVs measured on DCE MRI at C2, as well as at C4, of NAST can potentially predict pCR and non-pCR in TNBC patients.

Assessment of Early Response to Neoadjuvant Systemic Therapy in Triple-Negative Breast Cancer Using Amide Proton Transfer-weighted Chemical Exchange Saturation Transfer MRI: A Pilot Study.

Purpose To determine if amide proton transfer-weighted chemical exchange saturation transfer (APTW CEST) MRI is useful in the early assessment of treatment response in persons with triple-negative breast cancer (TNBC). Materials and Methods In this prospective study, a total of 51 participants (mean age, 51 years [range, 26-79 years]) with TNBC were included who underwent APTW CEST MRI with 0.9- and 2.0-µT saturation power performed at baseline, after two cycles (C2), and after four cycles (C4) of neoadjuvant systemic therapy (NAST). Imaging was performed between January 31, 2019, and November 11, 2019, and was a part of a clinical trial (registry number NCT02744053). CEST MR images were analyzed using two methods-magnetic transfer ratio asymmetry (MTRasym) and Lorentzian line shape fitting. The APTW CEST signals at baseline, C2, and C4 were compared for 51 participants to evaluate the saturation power levels and analysis methods. The APTW CEST signals and their changes during NAST were then compared for the 26 participants with pathology reports for treatment response assessment. Results A significant APTW CEST signal decrease was observed during NAST when acquisition at 0.9-µT saturation power was paired with Lorentzian line shape fitting analysis and when the acquisition at 2.0 µT was paired with MTRasym analysis. Using 0.9-µT saturation power and Lorentzian line shape fitting, the APTW CEST signal at C2 was significantly different from baseline in participants with pathologic complete response (pCR) (3.19% vs 2.43%; P = .03) but not with non-pCR (2.76% vs 2.50%; P > .05). The APTW CEST signal change was not significant between pCR and non-pCR at all time points. Conclusion Quantitative APTW CEST MRI depended on optimizing acquisition saturation powers and analysis methods. APTW CEST MRI monitored treatment effects but did not differentiate participants with TNBC who had pCR from those with non-pCR. © RSNA, 2021 Clinical trial registration no. NCT02744053 Supplemental material is available for this article.Keywords Molecular Imaging-Cancer, Molecular Imaging-Clinical Translation, MR-Imaging, Breast, Technical Aspects, Tumor Response, Technology Assessment.

Clinical utility and value contribution of an MRI-positive line marker for image-guided brachytherapy in gynecologic malignancies.

PURPOSE: The purpose of this study was to investigate the utility of a novel MRI-positive line marker, composed of C4:S (cobalt chloride-based contrast agent) encapsulated in high-density polyethylene tubing, in permitting dosimetry and treatment planning directly on MRI. METHODS AND MATERIALS: We evaluated the clinical feasibility of the C4:S line markers in nine sequential brachytherapy procedures for gynecologic malignancies, including six tandem-and-ovoid and three interstitial cases. We then quantified the internal resource utilization of an intraoperative MRI-guided procedural episode via time-driven activity-based costing, identifying opportunities for cost-containment with use of the C4:S line markers. RESULTS: The C4:S line markers demonstrated the strongest positive signal visibility on 3D constructive interference in steady state (CISS)/FIESTA-C followed by T1-weighted sequences, permitting accurate delineation of the applicator lumen and thus the source path. These images may be fused along with traditional T2-weighted sequences for optimal tumor and anatomy contouring, followed by treatment planning directly on MRI. By eliminating postoperative CT for fusion and applicator registration from the procedural episode, use of the C4:S line markers could decrease workflow time and lower total delivery costs per procedure. CONCLUSIONS: This analysis supports the clinical utility and value contribution of the C4:S line markers, which permit accurate MRI-based dosimetry and treatment planning, thereby eliminating the need for postoperative CT for fusion and applicator registration.

Feasibility of a reduced field-of-view diffusion-weighted (rFOV) sequence in assessment of myometrial invasion in patients with clinical FIGO stage I endometrial cancer.

PURPOSE: To compare the clinical usefulness of reduced field-of-view diffusion-weighted imaging (rFOV) with other imaging techniques in determining the depth of myometrial invasion (DMI) in endometrial cancer. MATERIALS AND METHODS: In this prospective study we reviewed 3T magnetic resonance images of 51 patients with clinical Stage I endometrial cancer who underwent total abdominal hysterectomy with bilateral salphingoopherectomy within 3 days after imaging. rFOV with apparent diffusion coefficient reconstruction was obtained in three standard planes followed by sagittal T2 -weighted (T2 WI) images and 3D dynamic T1 -weighted and contrast-enhanced imaging (DCE MRI). Two radiologists with expertise in imaging gynecologic cancers evaluated images independently. The DMI was recorded on imaging and correlated with surgical pathology results. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for DMI were calculated (<50% vs. >50%). RESULTS: Compared with sagittal T2 WI + DCE MRI, rFOV imaging yielded greater specificity (82.2% vs. 90.0%, positive predictive value (42.8% vs. 60.0%), and accuracy (84.0% vs. 92%) for DMI determined by reader 1 and greater the sensitivity (83.3% vs. 100%) for DMI determined by reader 2. The error of measurement of DMI as a continuous variable in millimeters did not differ significantly between the rFOV and pathology results (P < 0.21). However, there was a statistically significant difference for the DMI measured on the dynamic sequence. The DMI on DCE was greater than that seen on pathology at P = 0.02. CONCLUSION: rFOV can be used to assess DMI in clinical Stage I endometrial cancer.

Robust phase sensitive inversion recovery imaging using a Markov random field model.

This paper presents a novel method for phase sensitive inversion recovery (PSIR) imaging for improved T/sub 1/ contrast. This method models the phase of the complex magnetic resonance image using a statistical model based on Markov random fields. A computationally efficient optimization method is developed. Computer simulations and in-vivo brain imaging experiments show that the proposed method can produce PSIR images with enhanced T/sub 1/ contrast and it is robust against high levels of data noise even when rapid phase variations are presented.