Background: Currently, multi‐parametric prostate MRI (mpMRI) consists of a qualitative T₂, diffusion weighted, and dynamic contrast enhanced imaging. Quantification of T₂ imaging might further standardize PCa detection and support artificial intelligence solutions.Purpose: To evaluate the value of T₂ mapping to detect prostate cancer (PCa) and to differentiate PCa aggressiveness.Study Type: Retrospective single center cohort study.Population: Forty‐four consecutive patients (mean age 67 years; median PSA 7.9 ng/mL) with mpMRI and verified PCa by subsequent targeted plus systematic MR/ultrasound (US)‐fusion biopsy from February 2019 to December 2019.Field Strength/Sequence: Standardized mpMRI at 3 T with an additionally acquired T₂ mapping sequence.Assessment: Primary endpoint was the analysis of quantitative T₂ values and contrast differences/ratios (CD/CR) between PCa and benign tissue. Secondary objectives were the correlation between T₂ values, ISUP grade, apparent diffusion coefficient (ADC) value, and PI‐RADS, and the evaluation of thresholds for differentiating PCa and clinically significant PCa (csPCa).Statistical Tests: Mann–Whitney test, Spearman's rank (r_s) correlation, receiver operating curves, Youden's index (J), and AUC were performed. Statistical significance was defined as P < 0.05.Results: Median quantitative T₂ values were significantly lower for PCa in PZ (85 msec) and PCa in TZ (75 msec) compared to benign PZ (141 msec) or TZ (97 msec) (P < 0.001). CD/CR between PCa and benign PZ (51.2/1.77), respectively TZ (19.8/1.29), differed significantly (P < 0.001). The best T₂‐mapping threshold for PCa/csPCa detection was for TZ 81/86 msec (J = 0.929/1.0), and for PZ 110 msec (J = 0.834/0.905). Quantitative T₂ values of PCa did not correlate significantly with the ISUP grade (r_s = 0.186; P = 0.226), ADC value (r_s = 0.138; P = 0.372), or PI‐RADS (r_s = 0.132; P = 0.392).Data Conclusion: Quantitative T₂ values could differentiate PCa in TZ and PZ and might support standardization of mpMRI of the prostate. Different thresholds seem to apply for PZ and TZ lesions. However, in the present study quantitative T₂ values were not able to indicate PCa aggressiveness.Level of Evidence: 2Technical Efficacy: Stage 2

BACKGROUND AND PURPOSE: Impairment of tissue oxygenation caused by inhomogeneous microscopic blood flow distribution, the so-called capillary transit time heterogeneity, is thought to contribute to delayed cerebral ischemia after aneurysmal SAH but has so far not been systematically evaluated in patients. We hypothesized that heterogeneity of the MTT, derived from CTP parameters, would give insight into the clinical course of patients with aneurysmal SAH and may identify patients at risk of poor outcome. MATERIALS AND METHODS: We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation in CTP scans from 132 patients. A multivariable logistic regression model was used to model the dichotomized mRS outcome. Linear regression was used to eliminate variables with high linear dependence. T tests were used to compare the means of 2 groups. Furthermore, the time of the maximum coefficient of variation for MTT after bleeding was evaluated for correlation with the mRS after 6 months. RESULTS: On average, each patient underwent 5.3 CTP scans during his or her stay. Patients with high coefficient of variation for MTT presented more often with higher modified Fisher (P = .011) and World Federation of Neurosurgical Societies grades (P = .014). A high coefficient of variation for MTT at days 3–21 after aneurysmal SAH correlated significantly with a worse mRS score after 6 months (P = .016). We found no correlation between the time of the maximum coefficient of variation for MTT after bleeding and the patients’ outcomes after 6 months (P = .203). CONCLUSIONS: Heterogeneity of MTT in CTP after aneurysmal SAH correlates with the patients’ outcomes. Because the findings are in line with the pathophysiologic concept of the capillary transit time heterogeneity, future studies should seek to verify the coefficient of variation for MTT as a potential imaging biomarker for outcome.

Objectives: To investigate the specific strengths of MRI and PET components in ⁶⁸Ga-PSMA-11 PET/MRI for staging of patients with biochemically recurrent prostate cancer (PCa). Methods: Patients with biochemical recurrence of PCa and contrast-enhanced whole-body ⁶⁸Ga-PSMA-11 PET/MRI including a dedicated pelvic multiparametric MRI were included in this retrospective study. Imaging datasets of MRI and PET were evaluated separately regarding local PCa recurrence (Tr), pelvic lymph node metastases (N1), distant lymph node metastases (M1a), bone metastases (M1b), and soft tissue metastases (M1c) according to PROMISE version 1. Data evaluation was performed patient- and region-/lesion-based. Cox regression revealed a PSA of 1.69 ng/mL as a cut-off for subgroup analysis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were evaluated for each image component. Differences in staging accuracy were assessed using the Wilcoxon and McNemar test. Results: Altogether 102 patients (mean aged 68 ± 8 years, median PSA 1.33 ng/mL) were included. PCa was found in 70/102 (68%) patients. Accuracy of MRI in the detection of Tr, N1, M + , M1a, and M1b was 100%, 79%, 90%, 97%, and 95% for PSA < 1.69 ng/mL and 100%, 87%, 87%, 91%, and 96% for PSA > 1.69 ng/mL. Accuracy of ⁶⁸Ga-PSMA-11 PET was 93%, 97%, 93%, 98%, and 100% for PSA < 1.69 ng/mL and 87%, 91%, 96%, 100%, and 96% for PSA > 1.69 ng/mL. Conclusions: Combined assessment of ⁶⁸Ga-PSMA-11 PET/MRI improves tumor localization in men with biochemical recurrence. The MRI detected local recurrence of PCa more often whereas ⁶⁸ Ga-PSMA-11 PET detected lymph node metastases more often, especially for PSA < 1.69 ng/mL. Clinical relevance statement: This study gives a scientific baseline to improve the understanding and reading of ⁶⁸Ga-PSMA-11 PET/MRI imaging in patients with biochemically recurrent PCa by showing the specific strength of each imaging component. Key Points: • Combining the individual modality strengths of ⁶⁸Ga-PSMA-11 PET/MRI improves tumor localization in men with biochemical recurrence of prostate cancer. • MRI component of ⁶⁸ Ga-PSMA-11 PET/MRI shows its strength in detecting local recurrence of prostate cancer, especially at PSA < 1.69 ng/mL. • ⁶⁸ Ga-PSMA-11 PET component shows its strength in detecting local and distant lymph node metastases, especially at PSA < 1.69 ng/mL.

Background: This study compares the diagnostic potential of conventional staging (computed tomography (CT), axillary sonography and bone scintigraphy), whole-body magnetic resonance imaging (MRI) and whole-body ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET/)MRI for N and M staging in newly diagnosed breast cancer. Methods: A total of 208 patients with newly diagnosed breast cancer were prospectively included in this study and underwent contrast-enhanced thoracoabdominal CT, bone scintigraphy and axillary sonography as well as contrast-enhanced whole-body ¹⁸F-FDG PET/MRI. The datasets were analyzed with respect to lesion localization and characterization. Histopathology and follow-up imaging served as the reference standard. A McNemar test was used to compare the diagnostic performance of conventional staging, MRI and ¹⁸F-FDG PET/MRI and a Wilcoxon test was used to compare differences in true positive findings for nodal staging. Results: Conventional staging determined the N stage with a sensitivity of 80.9%, a specificity of 99.2%, a PPV (positive predictive value) of 98.6% and a NPV (negative predictive value) of 87.4%. The corresponding results for MRI were 79.6%, 100%, 100% and 87.0%, and were 86.5%, 94.1%, 91.7% and 90.3% for ¹⁸F-FDG PET/MRI. ¹⁸F-FDG PET/MRI was significantly more sensitive in determining malignant lymph nodes than conventional imaging and MRI (p < 0.0001 and p = 0.0005). Furthermore, ¹⁸F-FDG PET/MRI accurately estimated the clinical lymph node stage in significantly more cases than conventional imaging and MRI (each p < 0.05). Sensitivity, specificity, PPV and NPV for the M stage in conventional staging were 83.3%, 98.5%, 76.9% and 98.9%, respectively. The corresponding results for both MRI and ¹⁸F-FDG PET/MRI were 100.0%, 98.5%, 80.0% and 100.0%. No significant differences between the imaging modalities were seen for the staging of distant metastases. Conclusions:¹⁸F-FDG PET/MRI detects lymph node metastases in significantly more patients and estimates clinical lymph node stage more accurately than conventional imaging and MRI. No significant differences were found between imaging modalities with respect to the detection of distant metastases.

Objectives: To investigate the diagnostic feasibility of a shortened breast PET/MRI protocol in breast cancer patients. Methods: Altogether 90 women with newly diagnosed T1_tumor-staged (T1_ts) and T2_tumor-staged (T2_ts) breast cancer were included in this retrospective study. All underwent a dedicated comprehensive breast [¹⁸F]FDG-PET/MRI. List-mode PET data were retrospectively reconstructed with 20, 15, 10, and 5 min for each patient to simulate the effect of reduced PET acquisition times. The SUV_max/mean of all malign breast lesions was measured. Furthermore, breast PET data reconstructions were analyzed regarding image quality, lesion detectability, signal-to-noise ratio (SNR), and image noise (IN). The simultaneously acquired comprehensive MRI protocol was then shortened by retrospectively removing sequences from the protocol. Differences in malignant breast lesion detectability between the original and the fast breast MRI protocol were evaluated lesion-based. The 20-min PET reconstructions and the original MRI protocol served as reference. Results: In all PET reconstructions, 127 congruent breast lesions could be detected. Group comparison and T1_ts vs. T2_ts subgroup comparison revealed no significant difference of subjective image quality between 20, 15, 10, and 5 min acquisition times. SNR of qualitative image evaluation revealed no significant difference between different PET acquisition times. A slight but significant increase of IN with decreasing PET acquisition times could be detected. Lesion SUV_max group comparison between all PET acquisition times revealed no significant differences. Lesion-based evaluation revealed no significant difference in breast lesion detectability between original and fast breast MRI protocols. Conclusions: Breast [¹⁸F]FDG-PET/MRI protocols can be shortened from 20 to below 10 min without losing essential diagnostic information. Key Points: • A highly accurate breast cancer evaluation is possible by the shortened breast [¹⁸F]FDG-PET/MRI examination protocol. • Significant time saving at breast [¹⁸F]FDG-PET/MRI protocol could increase patient satisfaction and patient throughput for breast cancer patients at PET/MRI.

Purpose: This study seeks to evaluate MR imaging morphological factors and other covariates that influence the presence of residual glandular tissue after risk-reducing mastectomy in patients with a familial predisposition. Methods: We analyzed women of a high-risk collective with pathogenic mutation (BRCA1 (n = 49), BRCA2 (n = 24), or further mutation (n = 9)). A total of 117 breasts were analyzed, 63 left and 54 right, from a cohort of 81 patients, who were on average 40 years old. The mean follow-up was 63 months (range 12–180 months, SD = 39.67). Retrospective analysis of MR imaging data from 2006–2022 of patients of a high-risk collective (all carriers of a pathogenic mutation) with contralateral (RRCM) or bilateral risk-reducing mastectomy (RRBM) was performed. In the image data the remaining skin flap thickness by distance measurements at eight equally distributed, clockwise points and the retromamillary area, as well as by volumetry of each breast, was elected. Residual glandular tissue was also volumetrized. In addition, patient-related covariates were recorded and their influence on postoperative residual glandular tissue and skin flap thickness was analyzed by uni- and multivariate regressions. Results: A significant association with postoperative residual glandular tissue was shown in multivariate analysis for the independent variables breast density, skin flap mean, and surgical method (all p-values < 0.01). A negatively significant association could be seen for the variables preoperative breast volume (p-values < 0.01) and surgeon experience (most p-values < 0.05–<0.1). Conclusion: Postoperative residual glandular tissue is an important tool for quantifying the risk of developing breast cancer after risk-reducing mastectomy. Different effects on residual glandular tissue were shown for the independent variables breast density, skin flap, surgical method, preoperative breast volume, and surgeon experience, so these should be considered in future surgical procedures preoperatively as well as postoperatively. Breast MRI has proven to be a suitable method to analyze the skin flap as well as the RGT.