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PurposeTo assess image quality and diagnostic accuracy of low-dose computed tomography (CT) angiography using adaptive statistical iterative reconstruction V (ASiR-V) for evaluating the anatomy of renal vasculature in potential living renal donors.Materials and methodsEighty of 100 potential living renal donors were prospectively enrolled and underwent multiphase CT angiography (e.g., unenhanced, arterial, and venous phases) to evaluate the kidney for donation. Either low-dose using ASiR-V or standard protocol was randomly applied. Image quality was analyzed qualitatively and quantitatively with contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Renal artery and vein number, early branching vessel from renal arteries, and drainage of left-sided ascending lumbar vein to left renal vein were assessed. Reference standard for renal vasculature was surgical confirmation.ResultsSize-specific dose estimate of low-dose CT angiography (9.5 ± 0.8 mGy) was significantly lower than standard CT angiography (22.7 ± 4.1 mGy) (p < 0.001). Thus, radiation dose was reduced by 58.2% with low-dose CT. Both CNR and SNR of low-dose CT were significantly higher than those of standard CT (p < 0.001). Between the two CT methods, image quality was similar qualitatively (p > 0.05). Of 80 participants, 44 (55.0%) underwent nephrectomy. Both CT methods accurately predicted the anatomy of renal vasculature (standard CT, 100% for all variables; low-dose CT, 96.6% for renal vessel number or early branching vessel and 85.7% for drainage of left-sided ascending lumbar vein to left renal vein; p > 0.05 for all comparisons).ConclusionLow-dose CT angiography using ASiR-V is useful to evaluate renal vasculature for potential living renal donors.Key Points• In this prospective study, adaptive statistical iterative reconstruction V (ASiR-V) allowed 58.2% dose reduction while maintaining diagnostic image quality for renal vessels.• As compared with the standard protocol, the dose with ASiR-V was significantly lower (9.5 ± 0.8 mGy) than with standard computed tomography (CT) angiography (22.7 ± 4.1 mGy).• Low-dose CT using ASiR-V is useful for living donor evaluation before nephrectomy.

Objectives: To determine the effect of age and gender on diameters and lengths of the renal arteries. Methods: This is a retrospective study. A total of 50 asymptomatic volunteers were selected randomly and scanned by multi-detector CT to assess the diameters and lengths of the renal arteries. The study conducted at King Abdulaziz Specialized Hospital (KAASH) and King Faisal Hospitals, Taif, Saudi Arabia between October 2017 and March 2018. The lengths and diameters of the main arteries were measured and compared to age and gender of the participants. Results: The mean length of right renal artery was significantly longer than the left one (4.47[+ or -].70 versus 3.714[+ or -].68 cm, p<0.001). Length of right and left renal arteries were significantly higher in males than females (p=0.02 and p =0.03). Diameters of both left and right renal arteries were higher in males than females (5.482[+ or -]1.37 versus 5.288[+ or -]1.09 cm, and 5.544[+ or -]1.14 versus 5.188[+ or -]1.05 cm). The diameters of renal arteries varied significantly with age, specifically in elders (p=0.001). Conclusion: The mean length and mean diameter were significantly different between females and males, and between left and right main renal arteries. Age and gender have a significant impact on the length and diameters of main renal arteries. Keywords: renal arteries, computerized tomography, diameters, males, females [phrase omitted]

BackgroundAcute renal infarction (ARI) is a rare disease with atrial fibrillation being its main cause. The possible laterality of ARI is controversial. This study aimed to evaluate the association between anatomical features of the renal arteries and ARI.MethodsThis was a single-center cross-sectional study that evaluated the anatomical and clinical features of renal arteries. The anatomical features of the renal arteries were assessed using computed tomography.ResultsA total of 46 patients (mean age 71.3 ± 14.0 years; men, 59%) were enrolled. ARI involved the left kidney in 63%, right kidney in 28%, and both kidneys in 9% of patients. The right renal artery orifice was often higher than that of the left renal artery (71%). The angle of divergence from the abdominal aorta was similar on both sides. The left renal artery orifice was larger than that of the right (83 ± 24, 72 ± 24 mm2; p = 0.03, respectively). A larger left orifice was present in 72% of all cases. ARI involved the side with the larger orifice in 64% of patients.ConclusionThe size of the renal artery orifice may be a factor that contributes to the laterality of ARI. Assessment of anatomical features is important when considering the laterality of the disease.

The purpose was to evaluate the image quality of high-spatial resolution MRA of the renal arteries at 1.5 T after contrast-agent injection of 0.2 mmol/kg body weight (BW) in an interindividual comparison to 3.0 T after contrast-agent injection of 0.1 mmol/kg BW contrast agent (CA). After IRB approval and informed consent, 40 consecutive patients (25 men, 15 women; mean age 53.9 years) underwent MRA of the renal arteries either at a 1.5-T MR system with 0.2 mmol/kg BW gadobutrol or at a 3.0-T MR scanner with 0.1 mmol/kg BW gadobenate dimeglumine used as CA in a randomized order. A constant volume of 15 ml of these contrast agents was applied. The spatial resolution of the MRA sequences was 1.0 × 0.8 × 1.0 mm 3 at 1.5 T and 0.9 × 0.8 × 0.9 mm 3 at 3.0 T, which was achieved by using parallel imaging acceleration factors of 2 at 1.5 T and 3 at 3.0 T, respectively. Two radiologists blinded to the administered CA and the field strength assessed the image quality and the venous overlay for the aorta, the proximal and distal renal arteries independently on a four-point Likert-type scale. Phantom measurements were performed for a standardized comparison of SNR at 1.5 T and 3.0 T. There was no significant difference (p > 0.05) between the image quality at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine compared to the exams at 1.5 T with 0.2 mmol/kg BW gadobutrol. The median scores were between 3 and 4 (good to excellent vessel visualization) for the aorta (3 at 1.5 T/4 at 3.0 T for reader 1 and 2). For the proximal renal arteries, median scores were 3 for the left and right renal artery at 1.5 T for both readers. At 3.0 T, median scores were 3 (left proximal renal artery) and 4 (right proximal renal artery) for reader 1 and 3 (left/right) for reader 2 at 3.0 T. For the distal renal arteries, median scores were between 2 and 3 at both field strengths (moderate and good) for both readers. The κ values for both field strengths were comparable and ranged between 0.571 (moderate) for the distal renal arteries and 0.905 (almost perfect) for the proximal renal arteries. In the phantom measurements, a 40% higher SNR was found for the measurements at 3 T with gadobenate dimeglumine. High-spatial resolution renal MRA at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine yields at least equal image quality compared with renal MRA at 1.5 T with 0.2 mmol/kg BW gadobutrol.

Ultrasonography with color Doppler is the most quantitative analysis method for intra-renal parameters. There is a wide variation between authors in the measurement site and referencing the inter-lobar resistivity index (RI) in felines. Our objective is to morphometrically and ultrasonographically investigate the normal renal dimensions and vasculatures and draw up a normal reference value for the renal inter-lobar artery resistivity index (RI) using a Pulsed wave-Doppler ultrasonography. A total of twelve adult domestic cats were sedated and treated according to IACUC regulation guidelines to be examined using Doppler ultrasound. The same cats were used for morphometric investigation and divided into three groups regarding the used technique. The size difference between the right and left kidneys is slight, measuring 17 g (weight), 3.65 ± 0.06 cm (length), 2.54 ± 0.08 cm (width), and 2.21 ± 0.03 cm (thickness) for the right kidney, and about 15 g, 3.42 ± 0.06 cm, 2.32 ± 0.05 cm, and 2.13 ± 0.03 cm for the left one, respectively. There are three patterns of renal arteries’ point of origin. The mean RI values of both kidneys were 0.57 ± 0.08 (0.50–0.67) in the right kidney and 0.60 ± 0.08 (0.51–0.69) in the left kidney. The gross examination and ultrasonography measurements did not have a statistically different effect on the actual renal dimensions. Moreover, 0.69 is considered the standard resistivity index (RI) threshold of the feline inter-lobar artery with no correlation to the animal’s body weight.

Background Anatomical variations in the renal vasculature complicate surgical techniques and necessitate meticulous preoperative planning. This study aims to ascertain the prevalence and patterns of renal vascular variations in potential kidney transplant donors at Ahmed Gasim Teaching Hospital, Khartoum, Sudan, via computed tomography angiography (CTA). Methods A descriptive cross-sectional study was performed on 160 potential kidney donors who underwent renal CTA from January to December 2022. Data were collected via a checklist and analyzed with SPSS version 28. Variations in renal arteries, such as accessory renal arteries and premature bifurcations, have been reported and classified. Additional vascular variations were noted. Results Of the 160 subjects, 57.5% had normal single renal arteries bilaterally, whereas 42.5% had variations in renal artery anatomy. Accessory renal arteries were identified in 25.6% of the participants, whereas early branching occurred in 17%. Variations were more common in males, with 37% exhibiting accessory renal arteries compared with 16.1% in females ( p  = 0.008). Bilateral accessory renal arteries were identified in 3.8% of the donors. Circum-aortic left renal vein (1.3%) and Transposition of the inferior vena-cava (1.3%) were also detected. Conclusion A notable prevalence of renal artery variations was identified among these potential Sudanese kidney donors, with accessory arteries and early branching being the most common. Recognising such variations is crucial for safe surgical planning and optimal outcomes in kidney transplantation. While this study utilised CT angiography to delineate these vascular patterns, the importance lies in employing accurate and reliable imaging assessments—of which CTA is one valuable option—to guide preoperative evaluation and reduce surgical risks. Clinical trial registration Not applicable (this is an observational study).

This study was planned as an open-label, single-centre trial with blinded evaluations by two independent radiologists, aimed at the intra-individual comparison of single-dose and double-dose Gd-DTPA-enhanced MRA in the renal arterial territory. Ten healthy volunteers were included in the study. Renal MRAs were carried out on a clinical 1.5-T MR system using a body phased-array coil. Images were acquired with three-dimensional fast spoiled gradient echo sequence. Contrast agent was injected with a power injector keeping the injection time constant for single dose and double dose. Both readers found at least 96% of vascular segments evaluable. Median overall image quality was rated excellent, and diagnostic confidence was rated confident. No statistically significant difference between the dosage groups could be demonstrated. Signal intensity, SNR and CNR were significantly higher for the double-dose group. Our results demonstrate that while a double dose of contrast agent increases SNR, it does not lead to further improvement in visual and perceptual image quality. A single dosage of approximately 0.1 mmol/kg bw Gd-DTPA may be the preferable dosage to demonstrate the renal arteries.

Renal denervation (RDN) is a minimally invasive, endovascular catheter-based procedure using radiofrequency, ultrasound, or alcohol-mediated ablation to treat resistant hypertension. As more attention is focused on the renal sympathetic nerve as a cause and treatment target of hypertension, understanding the anatomy of the renal artery may have important implications for determining endovascular treatment strategies as well as for future selection of devices and appropriate candidates for RDN treatment. However, the anatomical structure of the renal artery (RA) is complex, and standardized morphological evaluations of the RA structure are lacking. Computed tomography angiography or magnetic resonance angiography imaging is useful for assessing RA anatomy before conducting RDN. RA echocardiography is an established noninvasive screening method for significant stenosis. Major randomized controlled trials have limited enrollment to patients with preserved renal function, usually defined as an estimated glomerular filtration rate (eGFR) ≥ 45 mL/min/1.73 m 2 . Therefore, the level of renal function at which RDN is indicated has not yet been determined. This mini-review summarizes the characteristics of renal artery anatomy and renal function that constitute indications for renal denervation. (Role of Clinical Trials: K. Kario is an Executive Committee Principal Investigator for the Spyral OFF MED, the Spyral ON MED, the DUO and the REQUIRE; a Coordinating investigator for the TCD-16164 study; a Site Principal Investigator for the HTN-J, the Spyral OFF MED, the Spyral ON MED, the DUO, the REQUIRE and the TCD-16164 study). Evaluation of renal arteries for radiofrequency renal denervation. A Simultaneous quadrantal ablations at four sites in the main renal artery or the equivalent renal artery to the main renal artery. B If there is a renal artery branch with a diameter >3 mm in the middle of the main renal artery, this branch is the distal end of the main renal artery. In this case, four simultaneous and quadrantal ablations can be performed on the equivalent renal arteries. C Four simultaneous and quadrantal ablations can be performed in the branch renal artery. D Sonication should be spaced at least 5 mm (one transducer*) apart. Perform 2 to 3 mm proximal to the arterial bifurcation. Perform 2 to 3 mm distal to the abdominal aortic inlet. Evaluation of renal arteries for radiofrequency renal denervation. (A) Simultaneous quadrantal ablations at four sites in the main renal artery or the equivalent renal artery to the main renal artery. (B) If there is a renal artery branch with a diameter >3 mm in the middle of the main renal artery, this branch is the distal end of the main renal artery. In this case, four simultaneous and quadrantal ablations can be performed on the equivalent renal arteries. (C) Four simultaneous and quadrantal ablations can be performed in the branch renal artery. (D) Sonication should be spaced at least 5 mm (one transducer*) apart. Perform 2 to 3 mm proximal to the arterial bifurcation. Perform 2 to 3 mm distal to the abdominal aortic inlet.

Through regulation of the extracellular fluid volume, the kidneys provide important long-term regulation of blood pressure. At the level of the individual functional unit (the nephron), pressure and flow control involves two different mechanisms that both produce oscillations. The nephrons are arranged in a complex branching structure that delivers blood to each nephron and, at the same time, provides a basis for an interaction between adjacent nephrons. The functional consequences of this interaction are not understood, and at present it is not possible to address this question experimentally. We provide experimental data and a new modeling approach to clarify this problem. To resolve details of microvascular structure, we collected 3D data from more than 150 afferent arterioles in an optically cleared rat kidney. Using these results together with published micro-computed tomography (μCT) data we develop an algorithm for generating the renal arterial network. We then introduce a mathematical model describing blood flow dynamics and nephron to nephron interaction in the network. The model includes an implementation of electrical signal propagation along a vascular wall. Simulation results show that the renal arterial architecture plays an important role in maintaining adequate pressure levels and the self-sustained dynamics of nephrons.

Renal sinus fat (RSF) is a perivascular fat compartment located around renal arteries. In this in vitro and in vivo study we hypothesized that the hepatokine fetuin-A may impair renal function in non alcoholic fatty liver disease (NAFLD) by altering inflammatory signalling in RSF. To study effects of the crosstalk between fetuin-A, RSF and kidney, human renal sinus fat cells (RSFC) were isolated and cocultured with human endothelial cells (EC) or podocytes (PO). RSFC caused downregulation of proinflammatory and upregulation of regenerative factors in cocultured EC and PO, indicating a protective influence of RFSC. However, fetuin-A inverted these benign effects of RSFC from an anti- to a proinflammatory status. RSF was quantified by magnetic resonance imaging and liver fat content by 1 H-MR spectroscopy in 449 individuals at risk for type 2 diabetes. Impaired renal function was determined via urinary albumin/creatinine-ratio (uACR). RSF did not correlate with uACR in subjects without NAFLD (n = 212, p = 0.94), but correlated positively in subjects with NAFLD (n = 105, p = 0.0005). Estimated glomerular filtration rate (eGRF) was inversely correlated with RSF, suggesting lower eGFR for subjects with higher RSF (r = 0.24, p < 0.0001). In conclusion, our data suggest that in the presence of NAFLD elevated fetuin-A levels may impair renal function by RSF-induced proinflammatory signalling in glomerular cells.