Research Presentation Session

RPS 1707 - Kidney and bladder problem solving: a different approach

Lectures

1
RPS 1707 - Discriminating tumours from inflammatory lesions after treatment for bladder cancer using diffusion kurtosis imaging

RPS 1707 - Discriminating tumours from inflammatory lesions after treatment for bladder cancer using diffusion kurtosis imaging

05:05F. Wang, Shanghai / CN

Purpose:

To investigate whether the parameters of diffusion kurtosis imaging (DKI) could discriminate recurrent or residual bladder tumours (RBT) from post-therapy bladder inflammatory lesions.

Methods and materials:

50 patients underwent magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) with 9 b-values ranging from 0 to 2000 s/mm2 after transurethral resection (TUR) or two cycles of neoadjuvant chemotherapy. The DKI parameters, including the mean diffusion coefficient (MDa,MDb,and MDc) and mean kurtosis (MKa,MKb, and MKc), were obtained from three different measurement methods. The ROI was placed (a) to encompass the entire portion of the thickening bladder wall or to portions that were the most restricted with b-values ranging from (b) 0-2000 s/mm2 or (c) 0-1000 s/mm2. Differences in DKI parameters between RBT and inflammatory lesions groups were assessed using Mann-Whitney tests, while the comparison between these parameters were analysed by comparing the areas under the receiver operating characteristic curves (AUC).

Results:

In patients with RBT, the MK values were significantly higher and the MD values were significantly lower than those in patients in the inflammatory-lesions group (all p<0.01). The AUC of MKb (0.934) was significantly larger than that of MDb, MKa, and MKc (0.793, p<0.05; 0.694, p<0.01; 0.719, p<0.01, respectively).

Conclusion:

MK obtained from DKI could provide better performance than conventional DWI in distinguishing RBT from inflammatory lesions after treatment for bladder cancer.

Limitations:

The samples were relatively small and we did not classify treatment effects into TUR and neoadjuvant chemotherapy groups.

Ethics committee approval

The study protocols were approved by the institutional review board and informed consent was obtained from all patients.

Funding:

National Natural Science Foundation of China; contract grant numbers: Youth Program No. 81601487, 81672514, 81601453.

2
RPS 1707 - Imaging protocols for renal multiparametric MRI and MR urography: results of a consensus conference from the French Society of Genitourinary Imaging

RPS 1707 - Imaging protocols for renal multiparametric MRI and MR urography: results of a consensus conference from the French Society of Genitourinary Imaging

08:11O. Rouviere, Lyon / FR

Purpose:

To develop technical guidelines for magnetic resonance imaging aimed at characterising renal masses (multiparametric magnetic resonance imaging and mpMRI) and the bladder and the upper urinary tract (magnetic resonance urography and MRU).

Methods and materials:

The French Society of Genitourinary organised a Delphi consensus conference with a two-round Delphi survey followed by a face-to-face meeting. Two separate questionnaires were issued for renal mpMRI and for MRU. Consensus was strictly defined using a priori criteria.

Results:

42 expert uro-radiologists completed both survey rounds with no attrition between the rounds. 56/84 (66.7%) statements of the mpMRI questionnaire and 44/71 (62%) statements of the MRU questionnaire reached a final consensus. For mpMRI, there was consensus that no injection of furosemide was needed and that the imaging protocol should include T2-weighted imaging, dual-chemical shift imaging, diffusion-weighted imaging (use of multiple b-values; maximal b-value: 1000 s/mm²) and fat-saturated single-bolus multiphase (unenhanced, corticomedullary, nephrographic) contrast-enhanced imaging; late imaging (more than 10 minutes after injection) was judged as optional. For MRU, the patients should void their bladder before the examination. The protocol must include T2-weighted imaging, anatomical fast T1/T2-weighted imaging, diffusion-weighted imaging (use of multiple b-values; maximal b-value: 1000 s/mm²), and fat-saturated single-bolus multiphase (unenhanced, corticomedullary, nephrographic, excretory) contrast-enhanced imaging. An intravenous injection of furosemide is mandatory before the injection of contrast medium. Heavily T2-weighted cholangiopancreatography-like imaging was judged optional.

Conclusion:

This expert-based consensus conference provides recommendations to standardise magnetic resonance imaging of kidneys, ureter, and bladder.

Limitations:

Consensus statements represent a low level of evidence.

The consensus conference did not address MR examinations aimed at evaluating bladder cancer local staging, nor protocol variations in children or pregnant women.

Ethics committee approval

n/a

Funding:

This work was funded by the French Society of Genitourinary Imaging (Société Française d'Imagerie Génito-urinaire)

3
RPS 1707 - The potential of apparent diffusion coefficient values as an independent marker for tumour aggressiveness in non-muscle-invasive bladder cancer

RPS 1707 - The potential of apparent diffusion coefficient values as an independent marker for tumour aggressiveness in non-muscle-invasive bladder cancer

04:56A. Rahota, Cluj-Napoca / RO

Purpose:

To determine whether the apparent diffusion coefficient (ADC) measured from diffusion-weighted imaging reflects quantitative information of the histological grading and clinical aggressiveness of non-muscle-invasive bladder cancer.

Methods and materials:

We prospectively enrolled 25 bladder tumours that have undergone 1.5T MRI DW images using b-values of 0, 50, and 800 s/mm2 in axial and sagittal planes. ADC values and their relationship with histological factors were measured for each lesion. The pathology report was considered a gold standard diagnosis.

Results:

14 lesions were low grade (LG) and 11 high grade (HG). 11 lesions were staged as pTa and 14 as pT1. The mean ADCs of LG and HG tumours were 1.25 × 10−3 mm2/s, respectively, 0.80 × 10−3 mm2/s, with a difference that was statistically significant (p<0.001). The cut-off value in the receiver operating characteristic (ROC) curve for differentiating LG and HG according to ADC values was 0.87 × 10−3 mm2/s (Se=72.7%, Sp=100%), with an area under curve (AUC) of 0.90. The mean values of ADC of pTa and pT1 tumours were 1.24 × 10−3 mm2/s and 0.80 × 10−3 mm2/s, respectively (p<0.001). No significant difference was found among the values of ADCs of axial versus sagittal acquisitions for tumours located on the lateral walls (1.12 × 10−3 mm2 /s vs. 1.21 × 10−3 mm2/s, p=0.56), or for tumours located on the inferior and superior walls (1.15 × 10−3 mm2/s vs 1.08 × 10−3 mm2/s, p=0.56).

Conclusion:

DW imaging with ADC measurement could become a novel non-invasive method for predicting tumour aggressiveness in bladder cancer.

Limitations:

A preliminary study and small sample size.

Ethics committee approval

All patients gave written informed consent.

Funding:

No funding was received for this work.

4
RPS 1707 - Veno-arterial index (VAI): a promising tool for renal transplant rejection

RPS 1707 - Veno-arterial index (VAI): a promising tool for renal transplant rejection

05:20F. Lubinus, Bucaramanga / CO

Purpose:

In transplant rejection, there is an increase in venous flow velocities and a decrease in arterial flow velocities, probably due to graft hardening.

Methods and materials:

A diagnostic study was carried out between January 2014 and May 2018. Renal transplanted patients who underwent percutaneous renal biopsy were studied. The veno-arterial index (VAI) was obtained by measuring the flow velocity in the segmental vein at the level of the renal medulla (VFV) and dividing this value by the velocity of the systolic peak of the segmental artery (PSV) in this same location.

Results:

78 records of patients who underwent renal biopsy were analysed. 32 patients (41.5%) suffered from transplant rejection, with 29 presenting with acute rejection. Prior to the study, a normal baseline value of the VAI was obtained by measuring the VAI in 70 individuals without known urological pathology, obtaining a VAI with a median value of 0.30 (range 0.18-0.44). In transplant rejection, the median VAI was 0.67. In kidneys with a negative biopsy for rejection, the median VAI was 0.41 (p=0.007), higher than that obtained for the general population which was 0.30 (p=0.0001). In subacute and acute rejection, the index was higher (VAI: 0.725). For the severity of rejection, the difference was also statistically significant (p = 0.0001).

Conclusion:

The results of this study show that the veno-arterial index (VAI) is a useful parameter which could predict transplant rejection when elevated.

Limitations:

Studies with a larger number of patients are required to confirm this hypothesis and to obtain a more accurate value of the VAI.

Ethics committee approval

Approved by the ethics committee.

Funding:

No funding was received for this work.

5
RPS 1707 - Role of diffusion-weighted imaging in the characterisation of renal masses

RPS 1707 - Role of diffusion-weighted imaging in the characterisation of renal masses

05:17A. Sever, Istanbul / TR

Purpose:

To investigate the role of diffusion-weighted imaging in the characterisation of renal masses.

Methods and materials:

Between January 2014 and December 2018, patients who had a histopathologically-proven renal tumour were reviewed retrospectively. Patients who had preoperative MRIs were included for the study. Diffusion-weighted images were taken and ADC maps were calculated automatically by the MRI unit. The average ADC values of masses were measured. SPSS was used to evaluate the statistical data.

Results:

Of the 142 patients, 108 had malignant masses and 34 had benign masses. Of the malignant patients, 59 had clear-cell RCC, 19 had papillary RCC, 14 had chromophobe RCC, 9 had TCC, and 7 had other rare subtypes. Of the benign patients, 6 had oncocytoma, 3 had angiomyolipoma, and 14 had papillary adenomas, metanephric adenomas, and infectious pseudotumours. 11 had benign cystic lesions of the kidneys.

The difference between ADC values of malignant and benign masses wasn’t statistically significant (0.92 vs 0.88 × 10–3 mm2/s; p>0.05). Clear-cell RCCs had higher ADC values than non-clear-cell RCCs (1.09 vs 0.73 × 10–3 mm2/s; p<0.05). RCCs had higher ADC values than non-RCCs (0.96 vs 0.69 × 10–3 mm2/s; p<0.05). Oncocytomas had higher ADC values than chromofobe RCCs (1.27 vs 0.73 × 10–3 mm2/s; p<0.05). The difference between low-grade RCCs (Fuhrman grade 1-2) and high-grade RCCs (Fuhrman grade 3-4) was statistically significant. Low-grade RCCs had higher ADC values (1.06 vs 0.9 × 10–3 mm2/s; p<0.05).

Conclusion:

ADC measurements may help in the differentiation of certain renal masses. It should be encouraged to be used in appropriate situations.

Limitations:

The retrospective nature of the study.

Ethics committee approval

Ethics committee approval obtained.

Funding:

No funding was received for this work.

6
RPS 1707 - Medullary oxygenation: an important index for evaluating renal function in chronic kidney disease

RPS 1707 - Medullary oxygenation: an important index for evaluating renal function in chronic kidney disease

05:51Pei Xin Long, Beijing / CN

Purpose:

BOLD-MRI can provide regional measurements of oxygen content using deoxyhaemoglobin paramagnetic characteristics. Chronic kidney disease (CKD) can affect oxygenation levels in renal parenchyma, which influences the clinical course of the disease. Furosemide may make Na+ -K+ -ATP pump work reduction and oxygen consumption decrease. The goal of this study was to assess renal oxygenation levels in CKD using BOLD-MRI when injecting furosemide.

Methods and materials:

18 healthy subjects and 39 patients with CKD underwent a renal scan using a multi-gradient-recalled-echo (mGRE) sequence with 16 echoes, and 28 of 39 patients underwent the same sequence 7 minutes after injecting furosemide. R2* values of three regions of interest (ROI) of the renal cortex and medulla were measured and their average values were calculated. The difference of R2* was compared between the healthy subjects and all patients. According to eGFR, 28 patients with injected furosemide were divided into a normal eGFR group (group 1,≥90 mL/min/1.73 m2) and an abnormal eGFR group (group 2,<90 mL/min/1.73 m2), and the changes of R2* in the two groups after injection were compared. 28 of the 39 patients were confirmed by ultrasound-guided puncture and the other 11 patients had a similar diagnosis based on clinical symptoms and investigations.

Results:

Medullary R2*(MR2*) were significantly lower in patients (78 kidneys, MR2*=28.81±4.65 s-1) than in controls (36 kidneys, MR2*=31.18±1.87s-1), P<0.05. Medullary to cortical R2* ratios of patients (1.78±0.26) was significantly decreased compared to controls (1.94±1.14), P<0.01. After injecting furosemide, R2* variance of the medulla (ΔMR2*=MR2*pre-MR2*post) in group 1 (6.63±0.66) was higher than that of group 2 (4.03±0.64), p<0.01.

Conclusion:

Medullary R2* values in BOLD-MRI when injecting furosemide were an effective index for evaluating renal oxygenation in CKD.

Limitations:

No differentiating specific pathogenesis of CKD.

Ethics committee approval

Informed consent was obtained from all participants.

Funding:

No funding was received for this work.

7
RPS 1707 - The change of total kidney volume after renal transplant in patients with autosomal polycystic renal disease: does it play a role in the indications and optimal timing decision for native kidney resection?

RPS 1707 - The change of total kidney volume after renal transplant in patients with autosomal polycystic renal disease: does it play a role in the indications and optimal timing decision for native kidney resection?

05:53L. Cacioppa, Bologna / IT

Purpose:

Autosomal dominant polycystic kidney disease (ADPKD) is characterised by a progressive enlargement of kidney cysts, often leading to end-stage disease with the need for renal transplantation (RT) and native kidney nephrectomy (NN). Few studies have investigated the appropriate timing for NN and the role of the change in total kidney volume (TKV) after RT in NN indications.

Methods and materials:

From January 2008 to December 2018, all polycystic patients who underwent RT in our centre were recorded and retrospectively reviewed. TKVs were evaluated with volumetric analyses on computed tomography (CT) scans performed before and one year after RT in patients who underwent RT alone, and in those scheduled for RT who also required NN. Mean TKV values were height/age, adjusted according to imaging classification of ADPKD (hTKV) and compared.

Results:

A total of 182 RTs were collected; 50 patients (27.5%) underwent NN (29 bilateral and 21 unilateral). NN procedures were pre-RT, post-RT, and simultaneous to RT in 54 (76%), 11 (15.5%), and 6 (8.5%), respectively; 34 (47.9%) due to symptoms occurrence and 37 (52.1%) to allow graft positioning. The median age was 54,6 ± 8,7. The mean hTKVs showed a non significant post-RT reduction in the group submitted to RT alone (1866.1±1005.2 vs 1863.2±1075.4 ml/m;p=ns). Compared to those submitted to RT alone, patients who underwent NN showed a higher mean pre-RT hTKV (2301.7±1100.7 vs 1651±994.3 ml/m;p=0.1).

Conclusion:

Despite the natural course of native polycystic kidneys, after RT is not well known and indications and timing of NN in patients scheduled for RT are controversial. Our study showed how TKV could be a measurable tool to determine critical kidney volumes at risk of complication and requiring future NN. Decisions for or against NN should take into account TKV reduction after RT and the presence of symptoms, complications, or unavailable graft space in order to avoid additive risks.

Limitations:

n/a

Ethics committee approval

n/a

Funding:

No funding was received for this work.

8
RPS 1707 - 3T blood-oxygen-level dependent (BOLD) MRI in renal transplants for the differentiation between acute rejection (AR) and acute tubular necrosis (ATN)

RPS 1707 - 3T blood-oxygen-level dependent (BOLD) MRI in renal transplants for the differentiation between acute rejection (AR) and acute tubular necrosis (ATN)

06:44A. Ramadan, Alexandria / EG

Purpose:

To assess the diagnostic accuracy of 3T BOLD-MRI for the differentiation of AR and ATN in the transplanted kidney.

Methods and materials:

This study included 75 renal graft recipients from living donors in 22 months. They were divided into group A, including 32 recipients with stable graft function, group B, and group C, including 25 and 18 recipients with pathologically proven AR and ATN, respectively. Each recipient was subjected to 3T BOLD-MRI using a breath-hold multiple fast-field echo sequence to obtain R2* maps in coronal planes. Qualitative analysis at colour-coded R2* maps and quantitative analysis by placing ROIs on R2* maps, measuring mean ±SD of C-R2* and M-R2*, and calculating MCR were performed. The ANOVA test was applied for comparison between different groups. ROC curve analysis determined the recommended cutoff values with corresponding sensitivity, specificity, PPV, NPV, and accuracy.

Results:

The study included 75 adult recipients; 32 as control and 43 with graft dysfunction. Pathology was 25 AR (group B) and 18 ATN (group C). Qualitative analysis showed a visual difference between different groups. Quantitative analysis revealed significantly higher C-and M-R2* values in the ATN group (21.20±2.54/s and 31.01±3.99/s) than in group A (14.96±1.61/s and 26.38±3.12/s) and the AR group (14.83±2.86/s and 22.28±5.29/s), respectively. For the prediction of ATN versus AR, the recommended cutoff value was >18.93/s and >26.35/s for C-R2* and M-R2*, respectively, with high sensitivity and specificity, and 90.7% accuracy. MCR was lower in the AR and ATN groups than in the control group, but no difference was found between the AR and ATN groups.

Conclusion:

3T BOLD-MRI is promising for the evaluation of renal grafts with the potential ability to differentiate between AR and ATN cases.

Limitations:

n/a

Ethics committee approval

n/a

Funding:

No funding was received for this work.

9
RPS 1707 - Quantitative analysis of wash-out parameters on an MRI DCE T1 weighted-sequence in adrenal lesions with a heterogeneous signal drop on chemical shift imaging

RPS 1707 - Quantitative analysis of wash-out parameters on an MRI DCE T1 weighted-sequence in adrenal lesions with a heterogeneous signal drop on chemical shift imaging

05:56R. Galatola, Napoli / IT

Purpose:

To assess the significance of a qualitative heterogeneous pattern of signal drop on chemical shift (CS) magnetic resonance imaging (MRI) of adrenal lesions (AL) employing quantitative parameters obtained from CS and dynamic contrast-enhanced (DCE) sequences.

Methods and materials:

This retrospective study included 3T MRI examinations with AL, for which histopathology, functional imaging, or follow-up data were available as a reference standard. Two radiologists qualitatively grouped AL on CS sequences, showing homogeneous (group A), heterogeneous (group B), and no (group C) signal drop. They manually drew 2D ROIs on CS and DCE images to obtain three quantitative parameters: adrenal signal intensity index (ASII), absolute (AWO), and relative washout (RWO). ANOVA analysis and a post-hoc Dunn’s test were used to compare these values among the three groups.

Results:

66 AL were included, divided into groups A (n=19), B (n=23), and C (n=24). ASII values resulted as significantly different among the three groups (p<0.001) with the following median values: 71%, 53%, and 0.03%, respectively. AWO and RWO values were not significantly different between groups A and B, showing percentages (AWO: 54% and 46% and RWO: 33% and 29%, respectively) suggestive of a benign nature. Indeed, 98% of lesions were benign, mostly (86%) represented by adenomas. Conversely, AWO and RWO values of group C resulted as significantly different (p<0.001) and lower (20% and 9%, respectively) than other groups. Indeed, 58% of these lesions were non-adenomas and the remaining percentage were lipid-poor adenomas.

Conclusion:

According to our results, AL showing a qualitative heterogeneous pattern of signal drop on CS images are mainly benign and represented by adenomas, showing dynamic quantitative parameters similar to those with a homogeneous signal drop on CS sequence.

Limitations:

A retrospective design and small population.

Ethics committee approval

IRB approved, consent waived.

Funding:

No funding was received for this work.

10
RPS 1707 - VI-RADS: do we really need all multiparametric data?

RPS 1707 - VI-RADS: do we really need all multiparametric data?

06:58J. Gmeiner, Vienna / AT

Purpose:

To investigate the diagnostic performance of the overall VI-RADS score and its individual parameters in assessing muscle invasivness and grade of bladder cancer (BCa).

Methods and materials:

In this IRB-approved, prospective single-centre cross-sectional observational study, patients with BCa underwent preoperative multiparametric MRI at 3T including T2w, DWI, and DCE images. Evaluation according to the VI-RADS scoring system was performed by two radiologists independently, blinded to histological findings. The performance of mpMRI and VI-RADS for determining muscle invasiveness and grade of BCa was compared by using ROC analysis.

Results:

The median age of 45 included patients was 67.6, range 28-90 years. Among 45 BCa, 13 (29%) were identified as muscle-invasive and 32 (71%) as non-invasive BCa. The AUC for VI-RADS to predict muscle invasion was 0.975 (95% CI: 0.877 to 0.999) and 0.866 for VI-RADS to distinguish high-grade from low-grade BCa (95% CI 0.728 to 0.951). There was no significant difference between the AUC of single parameters (DCE, T2w and DWI) compared to the total VI-RADS score (p=1.000, p=0.408, p=0.264 for muscle invasion; p=1.000, p=0.2644, p=0.828 for grading).

Conclusion:

Our results indicate that VI-RADS is an effective clinical decision rule to diagnose BCa grading and invasiveness. The inclusion of multiple parameters does not seem to be necessary. Therefore, contrast-enhanced sequences may be omitted as BCa patients regularly suffer from renal insufficiency.

Limitations:

Besides a small sample size, the main limitation of this study is the observational character that did not investigate the effect of VI-RADS on clinical decision making.

Ethics committee approval

The study protocol was approved by the Ethics Committee of the Medical University of Vienna.

Funding:

No funding was received for this work.

11
RPS 1707 - Validation of a prospective assessment of the vesical imaging-reporting and data system (VI-RADS) in high-risk non-muscle invasive bladder cancers (NMIBC) candidate for repeated transurethral resection

RPS 1707 - Validation of a prospective assessment of the vesical imaging-reporting and data system (VI-RADS) in high-risk non-muscle invasive bladder cancers (NMIBC) candidate for repeated transurethral resection

05:10M. Pecoraro, Rome / IT

Purpose:

To prospective validate VI-RADS in NMI-and-MIBC discrimination at TURBT. To identify HR-NMIBCs who could avoid Re-TURBT and to detect those at a higher risk for under-staging after TURBT.

Methods and materials:

Patients with a BCa suspicion were offered multiparametric magnetic resonance imaging (mpMRI) before TURBT. According to VI-RADS, a cutoff ≥3 to define MIBC was assumed. TURBT reports were compared with preoperative VI-RADS scores to assess the accuracy of mpMRI in discriminating NMI-and-MIBC. HR-NMIBCs Re-TURBT reports were compared with preoperatively recorded VI-RADS scores to assess mpMRI accuracy in predicting Re-TURBT outcomes. Sensitivity, specificity, and positive and negative predictive (PPV, NPV) values were calculated for mpMRI performance in patients undergoing TURBT and for HR-NMIBCs candidate for Re-TURBT. ROC curve and K statistics were calculated

Results:

231 patients were enrolled. MpMRI showed a sensitivity, specificity, PPV, and NPV in discriminating NMI-from-MIBC at initial TURBT of 91.9% (95%CI:82.2–97.3), 91.1% (95%CI: 85.8–94.9), 77.5% (95%CI:65.8–86.7), and 97.1% (95%CI:93.3–99.1), respectively. Area under curve (AUC) was 0.94 (95%CI:0.91–0.97). Within HR-NMIBCs (n=114), mpMRI before TURBT showed a sensitivity, specificity, PPV, and NPV of 85% (95%CI:62.1–96.8), 93.6% (95%CI: 86.6–97.6), 74.5% (95%CI: 52.4–90.1) and 96.6% (95%CI: 90.5–99.3), respectively, to identify patients with MIBC at Re-TURBT. AUC was 0.93 (95%CI: 0.87–0.97).

Conclusion:

VI-RADS is accurate for discriminating NMI-and-MIBC. Within HR-NMIBCs, VI-RADS could improve the selection of patients' candidate for Re-TURBT in the future.

Limitations:

MpMRI cannot yet be adopted for CIS and the sample is small in a single-centre.

Ethics committee approval

Approved by an ethical committee with a waiver of informed consent.

Funding:

No funding was received for this work.

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