Background:Renal interstitial fibrosis is a well-established prognostic indicator for kidney health, typically assessed via invasive biopsy. Diffusion-weighted magnetic resonance imaging (MRI) provides a non-invasive alternative by measuring the cortico-medullary difference in apparent diffusion coefficient (ΔADC), an inverse correlation with fibrosis has been reported in monocentric studies. This study evaluates the reproducibility of ΔADC across two centres and validates its diagnostic performance in native and allograft kidneys. The performance of T1 and T2 mapping is also assessed. Methods:In this prospective cohort study, patients with chronic kidney disease (CKD) and kidney allograft recipients from two hospitals underwent renal biopsy and MRI within 1 week. Correlations between ΔADC, T1 and T2 mapping, and histological fibrosis were assessed in the overall cohort and subgroups based on kidney type and biopsy indication. Receiver operating characteristic (ROC) analysis evaluated the performance of ΔADC for low and high fibrosis. Additional analyses examined correlation between MRI parameters, eGFR, and histological inflammation. A multivariable logistic regression identified predictors of high fibrosis. Results:Among 337 patients (121 CKD, 216 allografts), ΔADC correlated negatively with fibrosis (R = -0.42), consistently across centres and kidney type (native R = -0.49; allograft R = -0.39) and regardless of biopsy indication; T1 correlated only in native kidneys with fibrosis, whereas T2 correlated with degree of inflammation in biopsies with low fibrosis. ΔADC showed the best diagnostic accuracy for low (<25%) and high (>50%) fibrosis {AUCs 0.71 [CI95% (0.66;0.77)] and 0.83 [CI95% (0.76;0.91)]; cut-offs 41.5 and -32 × 10-6 mm²/s, respectively}. ΔADC, eGFR, proteinuria, and diabetes independently predicted high fibrosis {model AUC = 0.95 [CI95% (0.90; 0.99)]}. Conclusion:ΔADC reliably reflects renal fibrosis across two independent centres and kidney type, supporting diffusion MRI as a non-invasive tool for fibrosis assessment.

Renal interstitial fibrosis is a well-established prognostic indicator for kidney health, typically assessed via invasive biopsy. Diffusion-weighted MRI provides a non-invasive alternative by measuring the cortico-medullary difference in apparent diffusion coefficient (ΔADC), an inverse correlation with fibrosis has been reported in monocentric studies. This study evaluates the reproducibility of ΔADC across two centres and validates its diagnostic performance in native and allograft kidneys. The performance of T1 and T2 mapping is also assessed. In this prospective cohort study, patients with chronic kidney disease (CKD) and kidney allograft recipients from two hospitals underwent renal biopsy and MRI within one week. Correlations between ΔADC, T1 and T2 mapping and histological fibrosis were assessed in the overall cohort and subgroups based on kidney type and biopsy indication. ROC analysis evaluated the performance of ΔADC for low and high fibrosis. Additional analyses examined correlation between MRI parameters, eGFR, and histological inflammation. A multivariable logistic regression identified predictors of high fibrosis. Among 337 patients (121 CKD, 216 allografts), ΔADC correlated negatively with fibrosis (R=-0.42), consistently across centres and kidney type (native R=-0.49; allograft R=-0.39) and regardless of biopsy indication; T1 correlated only in native kidneys with fibrosis, whereas T2 correlated with degree of inflammation in biopsies with low fibrosis. ΔADC showed the best diagnostic accuracy for low (<25%) and high (>50%) fibrosis (AUCs: 0.71 (CI95% [0.66;0.77]) and 0.83 (CI95% [0.76;0.91]); cut-offs: 41.5 and -32 × 10⁻⁶ mm²/s, respectively). ΔADC, eGFR, proteinuria, and diabetes independently predicted high fibrosis (model AUC = 0.95 (CI95% [0.90; 0.99]). ΔADC reliably reflects renal fibrosis across two independent centres and kidney type, supporting diffusion MRI as a non-invasive tool for fibrosis assessment.

Background. Renal cortical interstitial fibrosis, typically assessed by biopsy, is crucial for kidney function prognosis. Magnetic resonance imaging (MRI) is a promising method to assess fibrosis non-invasively. Diffusion-weighted (DW) MRI correlates with renal fibrosis and predicts kidney function decline in chronic kidney disease (CKD) and kidney allograft patients. This study evaluates whether T1 and T2 mapping predict kidney function decline and if their simultaneous use enhances the predictive power of a DW-MRI-based model. Methods. We prospectively included 197 patients (42 CKD, 155 allograft kidneys). Each underwent a biopsy followed by multiparametric MRI without contrast within 1 week. Over a median follow-up of 2.2 years, laboratory parameters were recorded. The primary endpoint was a rapid decline in kidney function [glomerular filtration rate (GFR) reduction >30%] or replacement therapy initiation. The ability of T1 and T2 mapping sequences to predict poor renal outcome was examined using multivariable Cox regression models, incorporating MRI-derived parameters, estimated GFR (eGFR) and proteinuria. Results. Renal outcome occurred in 54 patients after a median of 1.1 years (interquartile range 0.9-2.1). Univariable survival analysis showed cortical T1 was associated with poor renal outcome {hazard ratio [HR] 3.02 [95% confidence interval (CI) 1.44-6.33]}, while T2 sequences had no significant predictive value. Adding cortical T1 to the established model (Delta ADC, eGFR, proteinuria) did not improve the HR [from 4.62 (95% CI 1.56-13.67) to 4.36 (95% CI 1.46-13.02)] and marginally increased Harrell's C-index (0.77 to 0.79). Adjusting the regression model for Delta T2 yielded no enhancement in predictive power. Conclusions. Cortical T1 is strongly associated with poor renal outcome but did not enhance prognostic power of the DW-MRI-based model.

Abstract Background and Aims Renal cortical interstitial fibrosis is a well-established prognostic indicator for renal health, conventionally estimated by biopsy. Our prior research has enhanced DW-MRI sequencing, facilitating precise distinction between the renal cortex and medulla. This has enabled the measurement of the cortico-medullary apparent diffusion coefficient difference (ΔADC), which inversely correlates with the extent of histologically assessed interstitial fibrosis. The present study is designed to validate these findings, assess their reproducibility in a separate institution, and ascertain their significance in delineated subgroups, particularly between allograft recipients and native kidney patients. Method From 2014 to 2023, we orchestrated a prospective cohort study encompassing 309 patients diagnosed with chronic kidney disease (n = 106) or those with a renal allograft (n = 203). Each patient had undergone a biopsy, subsequent to which a multimodal magnetic resonance imaging (MRI) was systematically conducted in the following weeks. Initially, participants were recruited from Geneva hospitals, with subsequent inclusion of patients from Lausanne in Switzerland. The study's objective was to evaluate the correlation between ΔADC and the degree of renal fibrosis at biopsy. We performed subgroup analyses (per center, native/allograft kidneys) and applied linear regression models to investigate these associations rigorously. Results We included 270 participants in Geneva and 39 patients in Lausanne. A significant negative correlation was observed between ΔADC and the degree of fibrosis across the entire cohort (R = −0.41, p < 0.001). Subgroup analyses yielded consistent findings in both Geneva (R = −0.43, p < 0.001) and Lausanne University Hospitals (R = −0.35, p < 0.001). Furthermore, this association remained significant within subgroups of both native and allograft kidneys (respectively: R = −0.48, p < 0.001 and R = −0.38, p < 0.001). Conclusion Our findings reinforce the link between ΔADC and renal fibrosis, indicating that this association is consistent regardless of the center or kidney type (native or allograft). This supports the potential utility of diffusion MRI as a non-invasive tool for the assessment of renal fibrosis.

Abstract Background and Aims Renal cortical interstitial fibrosis, typically measured by biopsy, is a critical factor for kidney function prognosis. Diffusion-weighted magnetic resonance imaging (DW-MRI) has emerged as a novel promising non-invasive method to assess the degree of fibrosis. We have previously shown that there is a strong correlation between the cortico-medullary apparent diffusion coefficient difference (ΔADC) and histologically assessed fibrosis. We also developed a model based on ΔADC, eGFR and proteinuria that calculates a risk score for future renal function decline. Multiparametric MRI combines DW-MRI with other sequences and can provide synchronized insights into perfusion, diffusion, oxygenation, and tissue characterization (T1 and T2 mappings). Our current research evaluates whether additional multiparametric MRI sequences increase the power of the DW-MRI based model to predict renal function decline. Method We used data from 197 patients with either chronic kidney disease (42) or allograft kidneys (155). Each participant underwent a biopsy followed by a multiparametric MRI within the following week. The median follow-up period was 2.2 years, during which laboratory parameters were recorded. The primary endpoint was defined as a rapid decline in kidney function, characterized by a reduction in eGFR of over 30%, or the initiation of dialysis. Prognostic factors for the primary outcome were analyzed using both univariable and multivariable Cox regression models, incorporating MRI parameters (ΔADC, cortical and ΔT1, cortical and ΔT2), eGFR, and proteinuria. Results At baseline, mean eGFR was 54.5 ml/min/1.73 m2 (SD 23.8) and mean proteinuria was 0.90 g/24 h (SD 2.4). Rapid decline of renal function occurred in 54 patients after a median time of 1.1 years (interquartile range, 0.9–2.1 years). In univariable survival analysis, cortical T1 measure and cortico-medullar difference ΔT2 have showed the best association to rapid kidney function decline. Compared to our previously established model incorporating ΔADC, eGFR, and proteinuria, adding cortical T1 did not significantly improve the hazard ratio (from 4.62 (95% CI: 1.56–13.67) to 4.36 (95% CI: 1.46–13.02) with cortical T1 inclusion). Harrell's C-index marginally increased with cortical T1, suggesting no significative improvement in prognostic capacity (0.77 versus 0.79 with cortical T1). Additionally, adjusting the regression model for ΔT2 yielded no enhancement in predictive power. Conclusion Our results did not demonstrate an enhancement of the prognostic power of the composite score with the inclusion of additional MRI sequences. Consequently, no clear benefit of multiparametric MRI on top of DW-MRI was observed. Additional research is required to investigate this issue more thoroughly.

Diffusion weighted imaging (DWI) constitutes a major functional parameter performed in Magnetic Resonance Imaging (MRI). The DW sequence is performed by acquiring a set of native images described by their b-values, each b-value representing the strength of the diffusion MR gradients specific to that sequence. By fitting the data with models describing the motion of water in tissue, an apparent diffusion coefficient (ADC) map is built and allows the assessment of water mobility inside the tissue. The high cellularity of tumors restricts the water diffusion and decreases the value of ADC within tumors, which makes them appear hypointense on ADC maps. The role of this sequence now largely exceeds its first clinical apparitions in neuroimaging, whereby the method helped diagnose the early phases of cerebral ischemic stroke. The applications extend to whole-body imaging for both neoplastic and non-neoplastic diseases. This review emphasizes the integration of DWI in the genitourinary system imaging by outlining the sequence’s usage in female pelvis, prostate, bladder, penis, testis and kidney MRI. In gynecologic imaging, DWI is an essential sequence for the characterization of cervix tumors and endometrial carcinomas, as well as to differentiate between leiomyosarcoma and benign leiomyoma of the uterus. In ovarian epithelial neoplasms, DWI provides key information for the characterization of solid components in heterogeneous complex ovarian masses. In prostate imaging, DWI became an essential part of multi-parametric Magnetic Resonance Imaging (mpMRI) to detect prostate cancer. The Prostate Imaging–Reporting and Data System (PI-RADS) scoring the probability of significant prostate tumors has significantly contributed to this success. Its contribution has established mpMRI as a mandatory examination for the planning of prostate biopsies and radical prostatectomy. Following a similar approach, DWI was included in multiparametric protocols for the bladder and the testis. In renal imaging, DWI is not able to robustly differentiate between malignant and benign renal tumors but may be helpful to characterize tumor subtypes, including clear-cell and non-clear-cell renal carcinomas or low-fat angiomyolipomas. One of the most promising developments of renal DWI is the estimation of renal fibrosis in chronic kidney disease (CKD) patients. In conclusion, DWI constitutes a major advancement in genitourinary imaging with a central role in decision algorithms in the female pelvis and prostate cancer, now allowing promising applications in renal imaging or in the bladder and testicular mpMRI.

OBJECTIVES:The aim of this pilot study was to investigate in two rectal cancer patients undergoing neoadjuvant chemo-radiotherapy (nCRT) the implant feasibility and dosimetric benefit in sexual organ-sparing of an injectable, absorbable, radiopaque hydrogel spacer. METHODS:Two rectal cancer patients (one male and one female) underwent hydrogel implant between rectum and vagina/prostate before nCRT and curative surgery. A CT scan was performed before and after injection and a comparative dosimetric study was performed testing a standard (45/50 Gy) and a dose escalated (46/55.2 Gy) schedule. RESULTS:In both patients, the spacer implant in the recto-prostatic or recto-vaginal space was feasible and well tolerated. For the male, the dosimetric benefit with spacer was minimal for sexual organs. For the female however, doses delivered to the vagina were significantly reduced with spacer with a mean reduction of more than 5 Gy for both regimens. CONCLUSIONS:For organ preservation protocols and selected sexually active female patients, use of hydrogel spacers can be considered to spare sexual organs from the high radiotherapy dose levels. ADVANCES IN KNOWLEDGE:For females with advanced rectal tumor, a spacer implant between the rectum and the vagina before nCRT is feasible and reduces doses delivered to the vagina.

19 kidney allografts patients had repeated biopsies for clinical purposes and parallel MRI examinations. There was no significant correlation between eGFR and renal interstitial fibrosis (IF) at baseline, whereas baseline deltaADC (a MRI derived parameter sensitive to the water diffusion in the tissue) correlated. negatively to renal interstitial fibrosis (IF). Considering the difference between the basal and follow-up values, there was a good correlation between the evolution of IF and deltaADC but not between the evolution of IF and eGFR. These results suggest that deltaADC may be more reliable than eGFR to allow earlier detection of an increase in IF.

To evaluate the diagnostic performance of a whole-body 18F-choline (FCH) hybrid PET/MRI for prostate cancer patients at biochemical relapse after radical prostatectomy (RP) compared to pelvic multiparametric MRI (mpMRI), one of the standard imaging modality for this patient population. From 2010 to 2016, 58 whole-body FCH PET/MRI studies with mpMRI acquisitions were performed in 53 prostate cancer patients relapsing after curative RP. Median PSA and PSA doubling time (PSA DT) at PET study were 1.5 ng/ml and 6.5 months, respectively. The overall positivity rate of FCH PET/MRI was 58.6% (n = 34), dropping to 44% in patients with a PSA ≤ 2 ng/ml (n = 36). Median PSA values in positive and negative PET/MRI studies were 2.2 ng/ml and 0.8 ng/ml, respectively, with no differences in PSA DT (6.5 vs. 6.6 months). A PSA value ≥ 1.5 ng/ml was a significant predictor of positivity on PET/MRI studies. Compared to PET, mpMRI identified more local relapses (17 vs. 14, p = 0.453) while PET outperformed whole-body Dixon MRI for regional (16 vs. 9, p = 0.016) and distant (12 vs. 6, p = 0.031) metastases. Compared to pelvic mpMRI, the treatment approach turned out to be influenced more frequently using whole-body FCH hybrid PET/MRI studies (58.6% vs. 38%). In prostate cancer patients with biochemical recurrence after RP, whole-body FCH PET/MRI achieved a higher detection rate of nodal/distant metastases compared to pelvic mpMRI alone, increasing the change of treatment strategy by more than 20%.

Distinguishing between kidney stones and phleboliths can constitute a diagnostic challenge in patients undergoing unenhanced low-dose CT (LDCT) for acute flank pain. We sought to investigate the accuracy of radiomics and a machine-learning classifier in differentiating between kidney stones and phleboliths on LDCT. Radiomics features were extracted following a semi-automatic segmentation of kidney stones and phleboliths for two independent consecutive cohorts of patients undergoing LDCT for acute flank pain. Radiomics features from the first cohort of patients (n = 369) were ultimately used to train a machine-learning model designed to distinguish kidney stones (n = 211) from phleboliths (n = 201). Classification performance was assessed on the second independent cohort (i.e., testing set) (kidney stones n = 24; phleboliths n = 23) using positive and negative predictive values (PPV and NPV), area under the receiver operating curves (AUC), and permutation testing. Our machine-learning classification model trained on radiomics features achieved an overall accuracy of 85.1% on the independent testing set, with an AUC of 0.902, PPV of 81.5%, and NPV of 90.0%. Classification accuracy was significantly better than chance on permutation testing (p < 0.05, permutation p value). Radiomics and machine learning enable accurate differentiation between kidney stones and phleboliths on LDCT in patients presenting with acute flank pain. • Combining a machine-learning algorithm with radiomics features extracted for abdominopelvic calcification on LDCT offers a highly accurate method for discriminating phleboliths from kidney stones. • Our radiomics and machine-learning model proved robust for CT acquisition and reconstruction protocol when tested in comparison with an external independent cohort of patients with acute flank pain. • The high performance of the radiomics-based automatic classification model in differentiating phleboliths from kidney stones indicates its potential as a future diagnostic tool for equivocal abdominopelvic calcifications in the setting of suspected renal colic.

Background. Kidney cortical interstitial fibrosis (IF) is highly predictive of renal prognosis and is currently assessed by the evaluation of a biopsy. Diffusion magnetic resonance imaging (MRI) is a promising tool to evaluate kidney fibrosis via the apparent diffusion coefficient (ADC), but suffers from inter-individual variability. We recently applied a novel MRI protocol to allow calculation of the corticomedullary ADC difference (Delta ADC). We here present the validation of Delta ADC for fibrosis assessment in a cohort of 164 patients undergoing biopsy and compare it with estimated glomerular filtration rate (eGFR) and other plasmatic parameters for the detection of fibrosis. Methods. This monocentric cross-sectional study included 164 patients undergoing renal biopsy at the Nephrology Department of the University Hospital of Geneva between October 2014 and May 2018. Patients underwent diffusion-weighted imaging, and T1 and T2 mappings, within 1 week after biopsy. MRI results were compared with gold standard histology for fibrosis assessment. Results. Absolute cortical ADC or cortical T1 values correlated poorly to IF assessed by the biopsy, whereas Delta ADC was highly correlated to IF (r= -0.52, P < 0.001) and eGFR (r= 037, P < 0.01), in both native and allograft patients. Delta T1 displayed a lower, but significant, correlation to IF and eGFR, whereas T2 did not correlate to IF nor to eGFR. Delta ADC, Delta T1 and eGFR were independently associated with kidney fibrosis, and their combination allowed detection of extensive fibrosis with good specificity. Conclusion. Delta ADC is better correlated to IF than absolute cortical or medullary ADC values. Delta ADC, Delta T1 and eGFR are independently associated to IF and allow the identification of patients with extensive IF.

Rationale and Objectives: To assess both the complete aorta and coronary artery disease (CAD) using low iodine contrast computed-tomography angiography before transcatheter aortic valve replacement. Materials and Methods: 84 patients underwent computed-tomography angiography before transcath-eter aortic valve replacement: 42 with standard iodine injection protocol (P1:120 mL); 42 with a low dose iodine injection protocol (P2:60 mL). Mean attenuation and subjective image quality were rated at different levels of the aorta, iliac and coronary arteries. Sensitivity, specificity, negative and positive pre-dictive values for depiction of CAD were calculated according to the coronary angiography. Results: Mean attenuation was significantly higher in P1 for the ascending aorta (p < 0.001). No significant difference was observed regarding image quality of the aortic valve (p = 0.876), the ascending aorta (p = 0.306), or the abdominal aorta (p = 1.0). Diagnostic image quality of coronary arteries was excellent for P1 and P2 (94.6% vs 96.5%, p = 0.08). Sensitivity, specificity, negative and positive predictive val-ues, and accuracy for depiction of CAD were excellent for P1 and P2 (100% vs 100%; 79% vs 86%, 70% vs 87%, 100% vs 100% and 86% vs 93%) without significant differences (p = 0.93; p = 0.58; p = 0.90; p = 1.0; p = 0.74), respectively. Conclusion: Despite a difference in aortic mean attenuation, a reduced iodine injection protocol showed similar image quality and detection of CAD in comparison with a standard injection protocol. (C) 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Introduction: The study aimed to evaluate 3 different modalities of transrectal ultrasound (TRUS)-guided prostate biopsies (PBs; 2D-, 3D- and targeted 3D-TRUS with fusion to MRI - T3D). Primary end point was the detection rate of prostate cancer (PC). Secondary end point was the detection rate of insignificant PC according to the Epstein criteria. Patients and Methods: Inclusion of 284 subsequent patients who underwent 2D-, 3D- or T3D PB from 2011 to 2015. All patients having PB for initial PC detection with a serum prostate-specific antigen value ≤20 ng/ml were included. Patients with T4 and/or clinical and/or radiological metastatic disease, so as these under active surveillance were excluded. Results: Patients with T3D PB had a significantly higher detection rate of PC (58 vs. 19% for 2D and 38% for 3D biopsies; p = 0.001), with no difference in Gleason score distribution (p = 0.644), as well as detection rate of low-risk cancers (p = 0.914). Main predictive factor for positive biopsies was the technique used, with respectively a 3- and 8-fold higher detection rate in the 3D- and T3D group. For T3D-PB, there was a significant correlation between radiological cancer suspicion (Prostate Imaging Reporting and Data System Score) and cancer detection rate (p = 0.02). Conclusions: T3D PB should be preferred over 2D PB and 3D PB in patients with suspected PC as it improves the cancer detection rate.

Hematospermia is a clinical symptom that raises anxiety in patients and has various causes, benign and malignant. We report a case of hematospermia for which appropriate multidisciplinary expertise favored a conservative management of a benign prostatic cyst, namely, a prostatic utricle cyst. A cystic lesion found by transrectal ultrasound in the context of hematospermia related to masturbation in a young virgin male patient was investigated with a high-field magnetic resonance imaging (MRI) and an endorectal coil. The association of high-field MRI and endorectal coil leads to high quality images.

Purpose: Tumor hypoxia is associated with radioresistance and poor prognosis after radiation therapy for prostate cancer (PCa). In this prospective pilot study, we assessed the ability of F-18-misonidazole (F-18-MISO) positron emission tomography (PET)-magnetic resonance imaging (MRI) to detect hypoxia in high-grade PCa patients who were candidates for curative radiation therapy, and we evaluated F-18-MISO PET-MRI modulation after 3 months of neoadjuvant androgen deprivation therapy (nADT). Methods and Materials: Eleven PCa patients with a Gleason score (GS) >= 8 underwent F-18-fluorocholine (F-18-FCH) PET-computed tomography at diagnosis and an F-18-MISO hybrid PET-MRI examination before nADT; a second F-18-MISO PET-MRI examination was acquired after 3 months of nADT for all patients but one who dropped out because of noncompliance with nADT. Immunohistochemistry for tissue hypoxia-and proliferation-related biomarkers (glucose transporter 1, carbonic anhydrase IX, vascular endothelial growth factor A, Ki-67, hypoxia-inducible factor 1 alpha, and epidermal growth factor receptor) was performed in lesions bearing the highest GS. We used nonparametric tests to assess (1) the presence of F-18-MISO-positive regions (tumor-to-background ratio [TBR] >= 1.4) at baseline; (2) the correlation between imaging parameters (PET tracer uptake, Prostate Imaging Reporting and Data System [PIRADS] scores, and dynamic contrast enhancement perfusion markers) at baseline; (3) the difference in immunohistochemistry staining between F-18-MISO-positive and -negative lesions; and (4) the changes in F-18-MISO PET-MRI after nADT. Results: Uptake of F-18-MISO was significant in 7 patients, being coincidental with the highest GS region in 5 of them. A significant correlation was found at baseline between GS and F-18-MISO TBR, between F-18-MISO TBR and MRI perfusion markers, between GS and F-18-FCH maximum standardized uptake value, between GS and PIRADS score, and between F-18-FCH maximum standardized uptake value and PIRADS score. No difference was found between F-18-MISO-positive and -negative biopsy specimens with respect to tissue biomarkers. The TBR of F-18-MISO diminished significantly after nADT only in high-grade lesions and in regions with a significant uptake at baseline. Conclusions: PET imaging with F-18-MISO showed variable uptake in PCa, associated with a higher GS, lowering significantly after 3 months of nADT in high-grade lesions. These results suggest the existence of a hypoxic microenvironment in PCa and a reoxygenation effect of nADT. (C) 2018 Elsevier Inc. All rights reserved.

Purpose To compare readout‐segmented echo‐planar imaging (EPI) (RESOLVE) to single‐shot EPI (ss‐EPI) diffusion‐weighted imaging (DWI) for the assessment of renal interstitial fibrosis. Materials and Methods A phantom, eight healthy volunteers (under 30 years to avoid age‐fibrosis related) and 27 chronic kidney disease (CKD) patients (scheduled for kidney biopsy) were scanned (at 3T) with ss‐EPI and 5‐shot RESOLVE DWI (resolution: 2 × 2 × 5 mm 3 , 10 b‐values). The cortico‐medullary difference for each DW parameter from a monoexponential fit (ΔADC) or, segmented biexponential fit (ΔD, ΔD*, ΔF p ) were compared between both sequences. A fibrosis threshold of 40% was defined to separate all 35 subjects into low and high fibrosis groups. The linear relationship between DW parameters and percentage fibrosis (up to 80%) from Masson trichrome was assessed with the Pearson product‐moment correlation coefficient. Fisher Z‐transform was used for R 2 correlation comparison. Results A coefficient of variation between ADCs of 3% was measured between both sequences in the phantom. In healthy volunteers, no significant difference was measured for all DW parameters. Both sequences separated low to high level of fibrosis with a significant decrease of ΔADC (RESOLVE P = 3.1 × 10 ‐6 , ss‐EPI P = 0.003) and ΔD (RESOLVE P = 8.2 × 10 ‐5 , ss‐EPI P = 0.02) in the high level of fibrosis. However, RESOLVE ΔADC had a stronger negative correlation ( P = 0.04 for R 2 comparison) with fibrosis than ss‐EPI ΔADC (RESOLVE R 2 = 0.65, P = 5.9 × 10 ‐9 , ss‐EPI R 2 = 0.29, P = 8.9 × 10 ‐4 ). ΔD (RESOLVE) was correlated (moderately) with fibrosis (R 2 = 0.29, P = 9.2 × 10 ‐4 ); however, ΔD* and ΔF p did not show, in our population, a significant correlation with interstitial fibrosis (0.01 < R 2 < 0.08). Conclusion ΔADC derived from both sequences correlated with fibrosis. ΔADC from RESOLVE showed better correlation with fibrosis than ΔADC from ss‐EPI and therefore has potential to monitor CKD. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1631–1640.

Objective: We demonstrate the use of a magnetic-resonance (MR)-compatible ultrasound (US) imaging probe using spatially resolved Doppler for diagnostic quality cardiovascular MR imaging (MRI) as an initial step toward hybrid US/MR fetal imaging. Methods: A newly developed technology for a dedicated MR-compatible phased array ultrasound-imaging probe acquired pulsed color Doppler carotid images, which were converted in near-real time to a trigger signal for cardiac cine and flow quantification MRI. Ultrasound and MR data acquired simultaneously were interference free. Conventional electrocardiogram (ECG) and the proposed spatially resolved Doppler triggering were compared in 10 healthy volunteers. A synthetic “false-triggered” image was retrospectively processed using metric optimized gating (MOG). Images were scored by expert readers, and sharpness, cardiac function and aortic flow were quantified. Four-dimensional (4-D) flow (two volunteers) showed feasibility of Doppler triggering over a long acquisition time. Results: Imaging modalities were compatible. US probe positioning was stable and comfortable. Image quality scores and quantified sharpness were statistically equal for Doppler- and ECG-triggering (p $= {\text{1.00}}$ ). ECG-, Doppler-triggered, and MOG ejection fractions were equivalent (p $ = {\text{1.00}}$), with false-triggered values significantly lower (p < 0.0005). Aortic flow showed no difference between ECG- and Doppler-triggered and MOG (p > 0.05). 4-D flow quantification gave consistent results between ECG and Doppler triggering. Conclusion: We report interference-free pulsed color Doppler ultrasound during MR data acquisition. Cardiovascular MRI of diagnostic quality was successfully obtained with pulsed color Doppler triggering. Significance: The hardware platform could further enable advanced free-breathing cardiac imaging. Doppler ultrasound triggering is applicable where ECG is compromised due to pathology or interference at higher magnetic fields, and where direct ECG is impossible, i.e., fetal imaging.