Objectives
To develop technical guidelines for magnetic resonance imaging aimed at characterising renal masses (multiparametric magnetic resonance imaging, mpMRI) and at imaging the bladder and upper ...urinary tract (magnetic resonance urography, MRU).
Methods
The French Society of Genitourinary Imaging 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
Forty-two expert uroradiologists completed both survey rounds with no attrition between the rounds. Fifty-six of 84 (67%) statements of the mpMRI questionnaire and 44/71 (62%) statements of the MRU questionnaire reached 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/mm
2
) and fat-saturated single-bolus multiphase (unenhanced, corticomedullary, nephrographic) contrast-enhanced imaging; late imaging (more than 10 min after injection) was judged 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/mm
2
) 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.
Key Points
• Multiparametric magnetic resonance imaging (mpMRI) aims at characterising renal masses; magnetic resonance urography (MRU) aims at imaging the urinary bladder and the collecting systems.
• For mpMRI, no injection of furosemide is needed.
• For MRU, an intravenous injection of furosemide is mandatory before the injection of contrast medium; heavily T2-weighted cholangiopancreatography-like imaging is optional.
Objectives
To develop technical guidelines for computed tomography urography.
Methods
The French Society of Genitourinary Imaging organised a Delphi consensus conference with a two-round Delphi ...survey followed by a face-to-face meeting. Consensus was strictly defined using a priori criteria.
Results
Forty-two expert uro-radiologists completed both survey rounds with no attrition between the rounds. Ninety-six (70%) of the initial 138 statements of the questionnaire achieved final consensus. An intravenous injection of 20 mg of furosemide before iodinated contrast medium injection was judged mandatory. Improving the quality of excretory phase imaging through oral or intravenous hydration of the patient or through the use of an abdominal compression device was not deemed necessary. The patient should be imaged in the supine position and placed in the prone position only at the radiologist’s request. The choice between single-bolus and split-bolus protocols depends on the context, but split-bolus protocols should be favoured whenever possible to decrease patient irradiation. Repeated single-slice test acquisitions should not be performed to decide of the timing of excretory phase imaging; instead, excretory phase imaging should be performed 7 min after the injection of the contrast medium. The optimal combination of unenhanced, corticomedullary phase and nephrographic phase imaging depends on the context; suggestions of protocols are provided for eight different clinical situations.
Conclusion
This expert-based consensus conference provides recommendations to standardise the imaging protocol for computed tomography urography.
Key Points
•
To improve excretory phase imaging, an intravenous injection of furosemide should be performed before the injection of iodinated contrast medium.
•
Systematic oral or intravenous hydration is not necessary to improve excretory phase imaging.
•
The choice between single-bolus and split-bolus protocols depends on the context, but split-bolus protocols should be favoured whenever possible to decrease patient irradiation.
Objective
To assess PI-RADSv2.1 and PI-RADSv2 descriptors across readers with varying experience.
Methods
Twenty-one radiologists (7 experienced (≥ 5 years) seniors, 7 less experienced seniors and 7 ...juniors) assessed 240 ‘predefined’ lesions from 159 pre-biopsy multiparametric prostate MRIs. They specified their location (peripheral, transition or central zone) and size, and scored them using PI-RADSv2.1 and PI-RADSv2 descriptors. They also described and scored ‘additional’ lesions if needed. Per-lesion analysis assessed the ‘predefined’ lesions, using targeted biopsy as reference; per-lobe analysis included ‘predefined’ and ‘additional’ lesions, using combined systematic and targeted biopsy as reference. Areas under the curve (AUCs) quantified the performance in diagnosing clinically significant cancer (csPCa; ISUP ≥ 2 cancer). Kappa coefficients (
κ
) or concordance correlation coefficients (CCC) assessed inter-reader agreement.
Results
At per-lesion analysis, inter-reader agreement on location and size was moderate-to-good (
κ
= 0.60–0.73) and excellent (CCC ≥ 0.80), respectively. Agreement on PI-RADSv2.1 scoring was moderate (
κ
= 0.43–0.47) for seniors and fair (
κ
= 0.39) for juniors. Using PI-RADSv2.1, juniors obtained a significantly lower AUC (0.74; 95% confidence interval 95%CI: 0.70–0.79) than experienced seniors (0.80; 95%CI 0.76–0.84;
p
= 0.008) but not than less experienced seniors (0.74; 95%CI 0.70–0.78;
p
= 0.75). As compared to PI-RADSv2, PI-RADSv2.1 downgraded 17 lesions/reader (interquartile range IQR: 6–29), of which 2 (IQR: 1–3) were csPCa; it upgraded 4 lesions/reader (IQR: 2–7), of which 1 (IQR: 0–2) was csPCa. Per-lobe analysis, which included 60 (IQR: 25–73) ‘additional’ lesions/reader, yielded similar results.
Conclusions
Experience significantly impacted lesion characterization using PI-RADSv2.1 descriptors. As compared to PI-RADSv2, PI-RADSv2.1 tended to downgrade non-csPCa lesions, but this effect was small and variable across readers.
Key points
Juniors characterized aggressive cancers less well than experienced seniors on prostate MRI.
Agreement between readers remained moderate even for experienced readers.
As compared to version 2, PI-RADSv2.1 descriptors tended to show improved specificity.
Transitional cell carcinoma with osseous metaplasia of the stroma is a rare variant of urothelial carcinoma which must be distinguished from sarcomatoid carcinoma. We report here a further ...observation of this tumor variant, in a very unusual location, the ureter, in order to underline the radiological and pathological characteristics useful for the correct diagnosis, and to point out the problems of differential diagnosis. The diagnosis was made in an 85-year-old patient, presenting with chronic right lombalgias. Imaging studies showed a calcified thickening of the right ureter, associated with a major dilatation of the right excretory cavities and a parenchymal atrophy of the right kidney. A right nephro-ureterectomy was performed. Macroscopical examination showed an ossified, ill-limited tumor, measuring 4 cm in diameter, infiltrating the right ureteral wall. At histological examination, the lesion was identified as a high grade transitional cell carcinoma with extensive osseous metaplasia of the stroma. There was no evidence for a sarcomatous component (absence of mesenchymal cell proliferation, absence of mitosis in stromal cells). An early locoregional recurrence was observed three months after surgery. Our case report underlines the radiological and histological features of a rare variant of transitional cell carcinoma, which may be diagnosed by pre-operative imaging studies and which must be distinguished from a highly aggressive sarcomatoid carcinoma.
