Objectives The aims of this study were to identify higher-grade clear cell renal cell carcinoma (cRCC) with native T1 mapping and to histologically correlate the results with the collagen volume fraction. Materials and Methods For this institutional review board–approved, single-center prospective study, 68 consecutive patients received abdominal magnetic resonance imaging scans at 1.5 T between January 2017 and July 2018, using a Modified Look-Locker Inversion Recovery (MOLLI) sequence. Thirty patients with cRCC (20 men; mean age, 61.9 ± 13.1 years) who underwent partial or radical nephrectomy and histological grading according to the International Society of Urological Pathology (ISUP) classification and a separate healthy cohort of 30 individuals without renal malignancies or complex cysts (16 men; mean age, 59.7 ± 14.6 years) met the eligibility criteria. T1 values were quantitatively measured with region of interest measurements in T1 maps. Quantification of the collagen volume fraction was performed on histological sections (picrosirius red staining). Results Native T1 values were significantly lower for lower-grade cRCC (ISUP 1 and 2) compared with higher-grade cRCC (ISUP 3 and 4; P < 0.001). A cutoff value of 1101 milliseconds distinguished higher-grade from lower-grade tumors with a sensitivity of 100% (95% confidence interval [CI], 0.69–1.00), a specificity of 85% (95% CI, 0.62–0.97), and an accuracy of 90% (95% CI, 0.73–0.98). Native T1 values were significantly associated with the histological collagen volume fraction (P < 0.05). Furthermore, T1 times in the renal cortex, medulla, and tumor tissue showed an excellent interobserver agreement. Conclusions Native T1 mapping could represent an in vivo biomarker for the differentiation of lower- and higher-grade cRCCs, providing incremental diagnostic value beyond qualitative magnetic resonance imaging features.

Background Correct staging and grading of patients with clear cell renal cell carcinoma (cRCC) is of clinical relevance for the prediction of operability and for individualized patient management. As partial or radial resection with postoperative tumor grading currently remain the methods of choice for the classification of cRCC, non-invasive preoperative alternatives to differentiate lower grade from higher grade cRCC would be beneficial. Methods This institutional-review-board approved cross-sectional study included twenty-seven patients (8 women, mean age ± SD, 61.3 ± 14.2) with histopathologically confirmed cRCC, graded according to the International Society of Urological Pathology (ISUP). A native, balanced steady-state free precession T2 mapping sequence (TrueFISP) was performed at 1.5 T. Quantitative T2 values were measured with circular 2D ROIs in the solid tumor portion and also in the normal renal parenchyma (cortex and medulla). To estimate the optimal cut-off T2 value for identifying lower grade cRCC, a Receiver Operating Characteristic Curve (ROC) analysis was performed and sensitivity and specificity were calculated. Students’ t-tests were used to evaluate the differences in mean values for continuous variables, while intergroup differences were tested for significance with two-tailed Mann-Whitney-U tests. Results There were significant differences between the T2 values for lower grade (ISUP 1–2) and higher grade (ISUP 3–4) cRCC ( p < 0.001), with higher T2 values for lower grade cRCC compared to higher grade cRCC. The sensitivity and specificity for the differentiation of lower grade from higher grade tumors were 83.3% (95% CI: 0.59–0.96) and 88.9% (95% CI: 0.52–1.00), respectively, using a threshold value of ≥110 ms. Intraobserver/interobserver agreement for T2 measurements was excellent/substantial. Conclusions Native T2 mapping based on a balanced steady-state free precession MR sequence might support an image-based distinction between lower and higher grade cRCC in a two-tier-system and could be a helpful addition to multiparametric imaging. Electronic supplementary material The online version of this article (10.1186/s40644-019-0222-8) contains supplementary material, which is available to authorized users.

Incidental DVT was prevalent in 11% of patients with clinically suspected PAOD. MRA with blood pool contrast agent has a potential role in the simultaneous assessment of arteries and veins and can detect concomitant venous disease affecting therapeutic management.

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To evaluate the use of susceptibility-weighted MRI for the differentiation of predominantly osteoblastic and osteolytic spine metastases. Materials and Methods: For this prospective study, 53 study participants (mean age, 54.5 years 6 14.3 [range, 22-88 years]; 27 men with a mean age of 55.3 years 6 12.7 [range, 22-72 years] and 26 women with a mean age of 53.8 years 6 15.7 [range, 23-88 years]) with clinically suspected spine metastases underwent imaging with standard MRI sequences, susceptibility-weighted MRI, and CT. Sensitivities and specificities of MRI sequences for the detection of predominantly osteoblastic and osteolytic metastases were determined by using CT as the reference standard. The metastases-to-vertebral body signal intensity ratio (MVR) was calculated to compare modalities. Phantom measurements were obtained to correlate bone densities between MRI sequences and CT. Results: A total of 64 metastases (38 predominantly osteoblastic, 26 predominantly osteolytic) were detected. Susceptibilityweighted MRI achieved a sensitivity of 100% (38 of 38) and specificity of 96% (25 of 26) for predominantly osteoblastic metastases and a sensitivity of 96% (25 of 26) and specificity of 100% (38 of 38) for predominantly osteolytic metastases. Standard MRI sequences achieved a sensitivity of 89% (34 of 38) and specificity of 73% (19 of 26) for predominantly osteoblastic metastases and a sensitivity of 73% (19 of 26) and specificity of 92% (35 of 38) for predominantly osteolytic metastases. MVR measurements obtained with susceptibility-weighted MRI demonstrated a strong correlation with those obtained with CT (R 2 = 0.75), whereas those obtained with T1-weighted MRI, T2-weighted MRI, and turbo inversion-recovery magnitude MRI showed a weak to moderate correlation (R 2 = 0.00, R 2 = 0.35, and R 2 = 0.39, respectively). Susceptibility-weighted MRI showed a strong correlation with CT with regard to metastases size (R 2 = 0.91). In phantom measurements, susceptibility-weighted MRI enabled the reliable differentiation of different degrees of mineralization (R 2 = 0.92 compared with CT). Conclusion: Susceptibility-weighted MRI enables the reliable differentiation between predominantly osteoblastic and osteolytic spine metastases with a higher accuracy than standard MRI sequences.

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Background: Magnetic resonance relaxometry (MRR) offers highly reproducible pixel-wise parametric maps of T1 and T2 relaxation times, reflecting specific tissue properties, while diffusion-tensor imaging (DTI) is a promising technique for the characterization of microstructural changes, depending on the directionality of molecular motion. Both MMR and DTI may be used for non-invasive assessment of parenchymal changes caused by kidney injury or graft dysfunction. Methods: We examined 46 patients with kidney transplantation and 16 healthy controls, using T1/T2 relaxometry and DTI at 3 T. Twenty-two early transplants and 24 late transplants were included. Seven of the patients had prior renal biopsy (all of them dysfunctional allografts; 6/7 with tubular atrophy and 7/7 with interstitial fibrosis). Results: Compared to healthy controls, T1 and T2 relaxation times in the renal parenchyma were increased after transplantation, with the highest T1/T2 values in early transplants (T1: 1700 ± 53 ms/T2: 83 ± 6 ms compared to T1: 1514 ± 29 ms/T2: 78 ± 4 ms in controls). Medullary and cortical ADC/FA values were decreased in early transplants and highest in controls, with medullary FA values showing the most pronounced difference. Cortical renal T1, mean medullary FA and corticomedullary differentiation (CMD) values correlated best with renal function as measured by eGFR (cortical T1: r = −0.63, p < 0.001; medullary FA: r = 0.67, p < 0.001; FA CMD: r = 0.62, p < 0.001). Mean medullary FA proved to be a significant predictor for tubular atrophy (p < 0.001), while cortical T1 appeared as a significant predictor of interstitial fibrosis (p = 0.003). Conclusion: Cortical T1, medullary FA, and FA CMD might serve as new imaging biomarkers of renal function and histopathologic microstructure.