dual-energy integrating detector CT

PURPOSE

To investigate the value of photon-counting detector CT (PCD-CT) derived virtual non-contrast (VNC) reconstructions to identify renal cysts in comparison with conventional dual-energy integrating detector (DE EID) CT-derived VNC reconstructions.

MATERIAL AND METHODS

We prospectively enrolled consecutive patients with simple renal cysts (Bosniak classification-Version 2019, density ≤ 20 HU and/or enhancement ≤ 20 HU) who underwent multiphase (non-contrast, arterial, portal venous phase) PCD-CT and for whom non-contrast and portal venous phase DE EID-CT was available. Subsequently, VNC reconstructions were calculated for all contrast phases and density as well as contrast enhancement within the cysts were measured and compared. MRI and/or ultrasound served as reference standards for lesion classification.

RESULTS

19 patients (1 cyst per patient; age 69.5 ± 10.7 years; 17 [89.5%] male) were included. Density measurements on PCD-CT non-contrast and VNC reconstructions (arterial and portal venous phase) revealed no significant effect on HU values (p = 0.301). In contrast, a significant difference between non-contrast vs. VNC images was found for DE EID-CT (p = 0.02). For PCD-CT, enhancement for VNC reconstructions was < 20 HU for all evaluated cysts. DE EID-CT measurements revealed an enhancement of > 20 HU in five lesions (26.3%) using the VNC reconstructions, which was not seen with the non-contrast images.

CONCLUSION

PCD-CT-derived VNC images allow for reliable and accurate characterization of simple cystic renal lesions similar to non-contrast scans whereas VNC images calculated from DE EID-CT resulted in substantial false characterization. Thus, PCD-CT-derived VNC images may substitute for non-contrast images and reduce radiation dose and follow-up imaging.

Effects of salt supplementation in uninephrectomized KK-Ay mice: Examining the potential of a diabetic kidney disease model

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD). Although current therapeutic strategies for DKD, including sodium-glucose cotransporter-2 inhibitors and mineralocorticoid receptor antagonists, have shown some degree of efficacy, they have failed to completely halt the progression of DKD to ESRD owing to the complexity of DKD pathogenesis. Elucidating the pathophysiological mechanism of DKD is essential for the development of novel therapeutic strategies. In this study, we investigated the pathophysiological characteristics of uninephrectomized (UNx) KK-Ay mice and examined the effects of salt supplementation on the acceleration of renal injury in these mice. UNx KK-Ay mice exhibited pathophysiological renal abnormalities with glomerular and tubulointerstitial fibrosis. Additionally, salt supplementation exacerbated renal injury, particularly tubular injury. These results suggest that UNx KK-Ay mice are useful models for advanced DKD and that salt exacerbates tubular damage in DKD.

Virtual monochromatic spectral attenuation curve analysis for evaluation of incidentally detected small renal lesions using rapid kilovoltage-switching dual-energy computed tomography

PURPOSE

To determine whether the spectral attenuation curve on a rapid kilovoltage-switching dual-energy computed tomography (DECT) scan can distinguish enhancing from nonenhancing incidental small (1-4 cm) renal lesions compared with conventional single-energy attenuation changes.

METHODS

This retrospective study enrolled 46 patients with 78 renal lesions (24 enhancing; 54 nonenhancing) who underwent DECT with DE mode performed during the portovenous or nephrographic phase. Final diagnosis of enhancing and nonenhancing masses was confirmed by pathology or imaging following the established criteria. Virtual monochromatic images (VMI) were reconstructed, and the slopes between the VMI dataset at 40-70 keV (Slope HU_40-70), 40-100 keV (Slope HU_40-100), and 40-140 keV (Slope HU_40-140) were measured. Visual assessment of the curve pattern was recorded. Diagnostic accuracies were calculated with a cross-validated Mann-Whitney U test, and correlations of quantitative spectral parameters and intraclass correlation coefficient (ICC) were calculated using Spearman's rho correlation.

RESULTS

All quantitative and qualitative spectral analysis parameters significantly differentiated the enhancing and nonenhancing lesions (P < 0.001). The optimal slope thresholds calculated by cross-validation for Slope HU_40-70, Slope HU_40-100, and Slope HU_40-140 were 3.0, 1.8 and 1.2, respectively for reader 1 and 3.0, 1.9 and 1.15, respectively for reader 2. Using a slope threshold at all datasets yielded a high diagnostic accuracy of 96 for reader 1 and 95 for reader 2. Using a ∆HU threshold of 20 HU yielded an accuracy of 100. Visual analysis of the curve pattern also yielded high accuracy of 94.

CONCLUSIONS

The spectral attenuation curve on rapid kilovoltage-switching DECT gives excellent diagnostic accuracy differentiating between incidental enhancing and nonenhancing renal lesions. This benefit of DECT will be most helpful when the true unenhanced phase is not performed.

A high-fat, high-fructose diet induced hepatic steatosis, renal lesions, dyslipidemia, and hyperuricemia in non-obese rats

Excessive consumption of fat and sugar is associated with various chronic diseases. However, the variation of fat and sugar content in the diet greatly affected the outcome. In this study, a high-fat, high-fructose diet (HFHFD) formula was made with a composition of 31.99% carbohydrate, 40.7% fat, 11.8% protein, and an additional 30% fructose drink to confirm the effects of HFHFD on metabolic health and pathological changes in organs, especially the liver, kidneys, pancreas, muscles, and spleen. A total of 24 male Wistar rats aged 8–12 weeks were divided into four groups: standard chow (SC), HFHFD, SC + carbon tetrachloride (CCl4), and HFHFD + CCl4. After eight weeks of dietary intervention, body mass index, obesity index, lipid profiles, liver function tests, fasting blood glucose, serum uric acid and urea levels, and tissue histopathology were examined. HFHFD with the main unsaturated fatty acids of linoleic acid (14.57%) and palmitoleic acid (8.28%), the main saturated fatty acids of stearic acid (13.62%) and myristic acid (10.09%), and a low trans-fatty acids content, did not promote the rats to become obese. However, liver histology examination showed severe hepatic steatosis (78.33%), leading to steatohepatitis accompanied by an increase in serum ALP (p < 0.01), triglyceride (p < 0.001), total cholesterol (p < 0.05), and uric acid (p < 0.001) levels. Other histological features showed moderate lesions (45%) of the kidney, slight vacuolization of the pancreas, and a mild increase of inflammatory cells in the spleen and muscle. So, this study found that although HFHFD did not promote obesity within 8 weeks of administration, it induced hepatic and renal lesions, dyslipidemia, and hyperuricemia as a metabolic consequence of excessive fatty acids and fructose.

Genetic spectrum and clinical characteristics of 3β-hydroxy-Δ5-C27-steroid oxidoreductase (HSD3B7) deficiency in China

BACKGROUND

Biallelic variants in HSD3B7 cause 3β-hydroxy-Δ5-C27-steroid oxidoreductase (HSD3B7) deficiency, a life-threatening but treatable liver disease. The goal of this study was to obtain detailed information on the correlation between the genotype and phenotype of HSD3B7 deficiency and to report on responses to primary bile acid therapy.

METHODS

The medical records of a cohort of 39 unrelated patients with genetically and biochemically confirmed HSD3B7 deficiency were examined to determine whether there exist genotype-phenotype relationships in this bile acid synthesis disorder.

RESULTS

In all, 34 of the 44 variants identified in HSD3B7 were novel. A total of 32 patients presented early with neonatal cholestasis, and 7 presented after 1-year of age with liver failure (n = 1), liver cirrhosis (n = 3), cholestasis (n = 1), renal cysts and abnormal liver biochemistries (n = 1), and coagulopathy from vitamin K1 deficiency and abnormal liver biochemistries (n = 1). Renal lesions, including renal cysts, renal stones, calcium deposition and renal enlargement were observed in 10 of 35 patients. Thirty-three patients were treated with oral chenodeoxycholic acid (CDCA) resulting in normalization of liver biochemistries in 24, while 2 showed a significant clinical improvement, and 7 underwent liver transplantation or died. Remarkably, renal lesions in 6 patients resolved after CDCA treatment, or liver transplantation. There were no significant correlations between genotype and clinical outcomes.

CONCLUSIONS

In what is the largest cohort of patients with HSD3B7 deficiency thus far studied, renal lesions were a notable clinical feature of HSD3B7 deficiency and these were resolved with suppression of atypical bile acids by oral CDCA administration.

Cost-effectiveness of dual-energy CT versus multiphasic single-energy CT and MRI for characterization of incidental indeterminate renal lesions

PURPOSE

To evaluate the cost-effectiveness of DECT versus multiphasic CT and MRI for characterizing small incidentally detected indeterminate renal lesions using a Markov Monte Carlo decision-analytic model.

BACKGROUND

Incidental renal lesions are commonly encountered due to the increasing utilization of medical imaging and the increasing prevalence of renal lesions with age. Currently recommended imaging modalities to further characterize incidental indeterminate renal lesions have some inherent drawbacks. Single-phase DECT may overcome these limitations, but its cost-effectiveness remains uncertain.

MATERIALS AND METHODS

A decision-analytic (Markov) model was constructed to estimate life expectancy and lifetime costs for otherwise healthy 64-year-old patients with small (≤ 4 cm) incidentally detected, indeterminate renal lesions on routine imaging (e.g., ultrasound or single-phase CT). Three strategies for evaluating renal lesions for enhancement were compared: multiphase SECT (e.g., true unenhanced and nephrographic phase), multiphasic MRI, and single-phase DECT (nephrographic phase in dual-energy mode). The model incorporated modality-specific diagnostic test performance, incidence, and prevalence of incidental renal cell carcinomas (RCCs), effectiveness, costs, and health outcomes. An incremental cost-effectiveness analysis was performed to identify strategy preference at willingness-to-pay (WTP) thresholds of $50,000 and $100,000 per quality-adjusted life-year (QALY) gained. Deterministic and probabilistic sensitivity analysis were performed.

RESULTS

In the base case analysis, expected mean costs per patient undergoing characterization of incidental renal lesions were $2567 for single-phase DECT, $3290 for multiphasic CT, and $3751 for multiphasic MRI. Associated quality-adjusted life-years were the highest for single-phase DECT at 0.962, for multiphasic MRI it was 0.940, and was the lowest for multiphasic CT at 0.925. Because of lower associated costs and higher effectiveness, the single-phase DECT strategy dominated the other two strategies.

CONCLUSIONS

Single-phase DECT is potentially more cost-effective than multiphasic SECT and MRI for evaluating small incidentally detected indeterminate renal lesions.

Sex differences in the development of vascular and renal lesions in mice with a simultaneous deficiency of Apoe and the integrin chain Itga8

Background

Apoe-deficient (Apoe^−/−) mice develop progressive atherosclerotic lesions with age but no severe renal pathology in the absence of additional challenges. We recently described accelerated atherosclerosis as well as marked renal injury in Apoe^−/− mice deficient in the mesenchymal integrin chain Itga8 (Itga8^−/−). Here, we used this Apoe^−/−, Itga8^−/− mouse model to investigate the sex differences in the development of atherosclerosis and concomitant renal injury. We hypothesized that aging female mice are protected from vascular and renal damage in this mouse model.

Methods

Apoe^−/− mice were backcrossed with Itga8^−/− mice. Mice were kept on a normal diet. At the age of 12 months, the aortae and kidneys of male and female Apoe^−/−Itga8^+/+ mice or Apoe^−/−Itga8^−/− mice were studied. En face preparations of the aorta were stained with Sudan IV (lipid deposition) or von Kossa (calcification). In kidney tissue, immunostaining for collagen IV, CD3, F4/80, and PCNA and real-time PCR analyses for Il6, Vegfa, Col1a1 (collagen I), and Ssp1 (secreted phosphoprotein 1, synonym osteopontin) as well as ER stress markers were performed.

Results

When compared to male mice, Apoe^−/−Itga8^+/+ female mice had a lower body weight, equal serum cholesterol levels, and lower triglyceride levels. However, female mice had increased aortic lipid deposition and more aortic calcifications than males. Male Apoe^−/− mice with the additional deficiency of Itga8 developed increased serum urea, glomerulosclerosis, renal immune cell infiltration, and reduced glomerular cell proliferation. In females of the same genotype, these renal changes were less pronounced and were accompanied by lower expression of interleukin-6 and collagen I, while osteopontin expression was higher and markers of ER stress were not different.

Conclusions

In this model of atherosclerosis, the female sex is a risk factor to develop more severe atherosclerotic lesions, even though serum fat levels are higher in males. In contrast, female mice are protected from renal damage, which is accompanied by attenuated inflammation and matrix deposition. Thus, sex affects vascular and renal injury in a differential manner.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-017-0141-y) contains supplementary material, which is available to authorized users.

MRI and contrast enhanced ultrasound (CEUS) image fusion of renal lesions

Ultrasound is a common and established imaging method for the initial characterization of renal lesions. The widespread used Bosniak classification (I-IV) classifies renal lesions in five individual groups using contrast-enhanced computer tomography (CE-CT), magnetic resonance imaging (MRI) and/or contrast-enhanced ultrasound (CEUS) imaging criteria. For complex pathologies, CEUS/MRI image fusion is a novel imaging technique for the differentiation of benign and malignant renal lesions. Compared to CE-CT and MRI alone, ultrasound image fusion offers the additional possibility of being a real-time imaging technique that can be used together with other cross-sectional imaging techniques.This article describes the newest possibilities of image fusion with CEUS and MRI in detection and characterization of unclear renal lesions.

Impact of contrast-enhanced ultrasound in patients with renal function impairment

AIM

To investigate the role of contrast enhanced ultrasound (CEUS) in evaluating patients with renal function impairment (RFI) showing: (1) acute renal failure (ARF) of suspicious vascular origin; or (2) suspicious renal lesions.

METHODS

We retrospectively evaluated patients addressed to CEUS over an eight years period to rule-out vascular causes of ARF (first group of 50 subjects) or assess previously found suspicious renal lesions (second group of 41 subjects with acute or chronic RFI). After preliminary grey-scale and color Doppler investigation, each kidney was investigated individually with CEUS, using 1.2-2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent. Image analysis was performed in consensus by two readers who reviewed digital clips of CEUS. We calculated the detection rate of vascular abnormalities in the first group and performed descriptive statistics of imaging findings for the second group.

RESULTS

In the first group, CEUS detected renal infarction or cortical ischemia in 18/50 patients (36%; 95%CI: 23.3-50.9) and 1/50 patients (2%; 95%CI: 0.1-12), respectively. The detection rate of infarction was significantly higher (P = 0.0002; McNemar test) compared to color Doppler ultrasonography (10%). No vascular causes of ARF were identified in the remaining 31/50 patients (62%). In the second group, CEUS detected 41 lesions on 39 patients, allowing differentiation between solid lesions (21/41; 51.2%) vs complex cysts (20/41; 48.8%), and properly addressing 15/39 patients to intervention when feasible based on clinical conditions (surgery and cryoablation in 13 and 2 cases, respectively). Cysts were categorized Bosniak II, IIF, III and IV in 8, 5, 4 and 3 cases, respectively. In the remaining two patients, CEUS found 1 pseudolesion and 1 subcapsular hematoma.

CONCLUSION

CEUS showed high detection rate of renal perfusion abnormalities in patients with ARF, influencing the management of patients with acute or chronic RFI and renal masses throughout their proper characterization.

Papillary renal cell carcinoma and clear cell renal cell carcinoma: Differentiation of distinct histological types with contrast - enhanced ultrasonography

PURPOSE

Papillary renal cell carcinoma (pRCC) and clear cell renal cell carcinoma (ccRCC) have different biological behaviours and imaging features. The role of contrast-enhanced ultrasound (CEUS) in differentiating these two carcinoma subtypes has not been comprehensively studied.

MATERIALS AND METHODS

Forty-eight patients with 49 pRCC lesions and 153 patients with 156 ccRCC lesions underwent preoperative conventional ultrasound (US) and CEUS. Among them, 91 patients (25 pRCCs and 66 ccRCCs) also underwent preoperative contrast-enhanced computed tomography (CECT) in our hospital. The characteristics of CEUS and CECT images for each patient imaged were analysed by each of two blinded observers.

RESULTS

Images for five (5/25, 20%) pRCC patients demonstrated equivocal or no enhancement using CECT, while all lesions were enhanced using CEUS. From CEUS, images of pRCCs, when compared with ccRCC images, demonstrated significantly higher frequencies of slow wash-in (59.2% vs. 5.8%), fast wash-out (87.7% vs. 46.1%), and hypo-enhancement (57.1% vs. 7.1%) patterns, p<0.001, as well as the presence of pseudocapsule (42.9% vs. 23.1%), p=0.007. For lesions with large diameters (> 3 cm), a higher percentage of pRCC images demonstrated homogeneous enhancement compared with ccRCC images. Using the combination of slow wash-in, fast wash-out, and hypoenhancement patterns at peak as criteria to differentiate pRCC from ccRCC, positive and negative predictive value, and sensitivity and specificity were found to be 86.7%, 86.9%, 53.1%, and 97.4%, respectively.

CONCLUSIONS

CEUS imaging features of slow-in, fast-out, and hypo-enhancement patterns may be useful for differentiating pRCC and ccRCC. In addition, CEUS may be helpful for diagnosing hypovascular renal lesions that demonstrate equivocal or no enhancement by CECT and, thus, for improving diagnostic confidence.

Clinical and laboratory indices of severe renal lesions in children with febrile urinary tract infection

AIM

To evaluate the predictive value of various clinical and laboratory parameters on the identification of acute extensive and/or multifocal renal involvement in children with febrile urinary tract infections (UTI).

METHODS

The medical records of 148 children (median age: 2.4 months, range: 11 days-24 months), who were admitted during a 3-year period with a first episode of febrile UTI, were analysed. Acute dimercaptosuccinic acid scintigraphy (DMSA), clinical and laboratory parameters were evaluated.

RESULTS

Seventy six children (51%) had abnormal findings on the acute DMSA. Of them, 20 had DMSA grade 2, while 56 had grade 3 and 4. Patients with a DMSA grade 3 and 4 were more likely to have shivering (OR 3.4), white blood count (WBC) ≥ 18 000/μL (OR 2.4), absolute neutrophil count (ANC) ≥ 9300/μL (OR 4.4), C-reactive protein (CRP) ≥ 50 mg/L (OR 2.7) and procalcitonin (PCT) ≥ 1.64 ng/mL (OR diagnostic). There was a significant difference of WBC (p = 0.004), ANC, CRP and PCT levels (p < 0.001) between children with normal and grade 2 aDMSA versus those with aDMSA grade 3 and 4.

CONCLUSIONS

Shivering and elevated inflammatory markers increase the risk of acute extensive and/or multifocal kidney involvement in children with febrile UTI. Procalcitonin seems to be an excellent marker of the severity of acute parenchymal involvement.

Computer-aided detection of exophytic renal lesions on non-contrast CT images

Renal lesions are important extracolonic findings on computed tomographic colonography (CTC). They are difficult to detect on non-contrast CTC images due to low image contrast with surrounding objects. In this paper, we developed a novel computer-aided diagnosis system to detect a subset of renal lesions, exophytic lesions, by (1) exploiting efficient belief propagation to segment kidneys, (2) establishing an intrinsic manifold diffusion on kidney surface, (3) searching for potential lesion-caused protrusions with local maximum diffusion response, and (4) exploring novel shape descriptors, including multi-scale diffusion response, with machine learning to classify exophytic renal lesions. Experimental results on the validation dataset with 167 patients revealed that manifold diffusion significantly outperformed conventional shape features (p<1e-3) and resulted in 95% sensitivity with 15 false positives per patient for detecting exophytic renal lesions. Fivefold cross-validation also demonstrated that our method could stably detect exophytic renal lesions. These encouraging results demonstrated that manifold diffusion is a key means to enable accurate computer-aided diagnosis of renal lesions.

Multiphase renal CT in the evaluation of renal masses: is the nephrographic phase necessary?

The aim of this study is to investigate the feasibility of eliminating the nephrographic phase from the four-phase renal computed tomography (CT) imaging to a three-phase protocol without affecting its diagnostic value. Thirty patients undergoing four-phase renal CT scans for assessment of renal lesions (>10 mm) were included in the study. A three-phase renal CT, without nephrographic phase, had similar diagnostic ability to a four-phase renal CT in the detection and characterization of renal lesions. A three-phase CT (plain, corticomedullary, and excretory phase) is therefore adequate in the clinical diagnosis of renal lesions.

Amelioration of cisplatin-induced mouse renal lesions by a cyclooxygenase (COX)-2 selective inhibitor

In this study, we investigated the effects of the cyclooxygenase (COX)-2 selective inhibitor, meloxicam, on cisplatin-induced inflammation, oxidative stress and renal lesions in BALB/c mice. A single cisplatin injection (13 mg/kg, i.p.) significantly increased plasma creatinine, blood urea nitrogen and urinary glucose accompanied by a concomitant increase in COX-2 mRNA and COX-2 protein levels. These changes in renal lesion parameters were diminished by simultaneous treatment of meloxicam (0.7 mg/kg/day in drinking water). The expression of oxidative stress markers, p47(phox), p67(phox), hemoxygenase-1 (HO-1), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and 4-hydroxy-2-nonenal (4-HNE)-modified protein were increased with cisplatin injection. Simultaneous treatment of meloxicam with cisplatin significantly inhibited the increase in p47(phox), HO-1 and 4-HNE-modified protein. The phosphorylation of extracellular regulated kinase (ERK) and c-jun-N-terminal kinase (JNK) were increased with cisplatin injection, but these changes were inhibited by meloxicam. Moreover, concomitant meloxicam treatment also prevented the cisplatin-induced infiltration of macrophages to the tubulointerstitial area. These results suggest that meloxicam can ameliorate cisplatin-induced mouse renal lesions, potentially through the inhibition of inflammatory and oxidative stress responses.