Utility of MRI in the Characterization of Indeterminate Small Renal Lesions Previously Seen on Screening CT Scans of Potential Renal Donor Patients

Hand-assisted retroperitoneoscopic donor nephrectomy offers more liberal use of right kidneys: lessons learned from 565 cases - a retrospective single-center study

The introduction of laparoscopic donor nephrectomy caused a shift toward' left donor nephrectomy. Some centers report a significantly low rate of endoscopic right donor nephrectomy. Hand-assisted retroperitoneoscopic donor nephrectomy (HARP-DN) was introduced as a novel surgical technique, which aims to avoid intra-abdominal complications. It was also reported to provide technical advantages for right-sided DN. In this retrospective single-center study, we evaluated the impact of HARP-DN technique on utilization of right-sided DNs. After the implementation of HARP-DN on February 2009, a total of 565 DNs were performed until December 2015. The introduction of HARP-DN technique resulted in an immediate increase in the utilization of right kidneys from 6.1% to an average of 19.6% annually. The donors 'outcome was similar to the left-sided and right-sided DN groups, excluding the increased incidence of incisional hernias in left kidney donors. None of the donors developed intra-abdominal complications. In conclusion, the implementation of HARP technique significantly increased the use of right-sided DNs, which enables a more liberal use of donors in LDKT.

CT and MR imaging of cystic renal lesions

Cystic renal lesions are a common incidental finding on routinely imaging examinations. Although a benign simple cyst is usually easy to recognize, the same is not true for complex and multifocal cystic renal lesions, whose differential diagnosis includes both neoplastic and non-neoplastic conditions. In this review, we will show a series of cases in order to provide tips to identify benign cysts and differentiate them from malignant ones.

Comparison of Diagnostic Medical Sonography, Computed Tomography, Magnetic Resonance Imaging, and Contrast-Enhanced Ultrasound in the Investigation of Renal Lesions

This review explores the classification and evaluation of suspicious renal lesions across several radiologic imaging modalities. Diagnostic medical sonography (DMS), computed tomography (CT), magnetic resonance imaging (MRI), and contrast-enhanced ultrasound (CEUS) are the primary modalities used to investigate questionable lesions found within the kidneys. Renal masses may range from completely benign to malignant. They are classified based on many different features and characteristics. These lesions may be simple cystic, complex cystic, or solid in nature. Masses may also exhibit varying degrees of vascularity, septations, and calcifications. The discussed imaging modalities have varying strengths, limitations, and implications for use. Imaging techniques may be used independently or in conjunction to best diagnose and treat a patient with a suspicious renal mass. The aim of this review was to describe the diagnostic value of the imaging modalities (DMS, CT, MRI, and CEUS) and their role in the evaluation of suspicious renal lesions.

Differential diagnosis of the small renal masses: role of the apparent diffusion coefficient of the diffusion-weighted MRI

INTRODUCTION

Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and more than 90% of neoplasms arising from the kidney. Uninformative percutaneous kidney biopsies vary from 10 to 23%. As a result, 7.5-33.6% of partial nephrectomies in patients with small renal masses (SRM) are performed on benign renal tumors. The aim of this study was to assess the feasibility of the apparent diffusion coefficient (ADC) of the diffusion-weighted imaging (DWI) of MRI, as RCC imaging biomarker for differentiation of SRM.

METHOD

Adult patients (n = 158) with 170 SRM were enrolled into this study. The control group were healthy volunteers with normal clinical and radiologic findings (n = 15). All participants underwent MRI with DWI sequence included.

RESULTS

Mean ADC values of solid RCC (1.65 ± 0.38 × 10^-3 mm²/s) were lower than healthy renal parenchyma (2.47 ± 0.12 × 10^-3 mm²/s, p < 0.05). There was no difference between mean ADC values of ccRCC, pRCC and chRCC (1.82 ± 0.22 × 10^-3 vs 1.61 ± 0.07 × 10^-3 vs 1.46 ± 0.09 × 10^-3 mm²/s, respectively, p = ns). An inverse relationship between mean ADC values and Fuhrman grade of nuclear atypia of solid ccRCCs was observed: grade I-1.92 ± 0.11 × 10^-3 mm²/s, grade II-1.84 ± 0.14 × 10^-3 mm²/s, grade III-1.79 ± 0.10 × 10^-3 mm²/s, grade IV-1.72 ± 0.06 × 10^-3 mm²/s. This was significant (p < 0.05) only between tumors of I and IV grades. Significant difference (p < 0.05) between mean ADC values of solid RCCs, benign renal tumors and renal cysts was observed (1.65 ± 0.38 × 10^-3 vs 2.23 ± 0.18 × 10^-3 vs 3.15 ± 0.51 × 10^-3 mm²/s, respectively). In addition, there was a significant difference (p < 0.05) in mean ADC values between benign cysts and cystic RCC (3.36 ± 0.35 × 10^-3 vs 2.83 ± 0.21 × 10^-3 mm²/s, respectively).

CONCLUSION

ADC maps with b values of 0 and 800 s/mm² can be used as an imaging biomarker, to differentiate benign SRM from malignant SRM. Using ADC value threshold of 1.75 × 10^-3 mm²/s allows to differentiate solid RCC from solid benign kidney tumors with 91% sensitivity and 89% specificity; ADC value threshold of 2.96 × 10^-3 mm²/s distinguishes cystic RCC from benign renal cysts with 90% sensitivity and 88% specificity. However, the possibility of differentiation between ccRCC histologic subtypes and grades, utilizing ADC values, is limited.

Magnetic Resonance Imaging and the Use in Small Renal Masses

The incidence of small renal masses (SRM) has been increasing, and this is mainly attributed to the incidental finding of such masses on imaging performed in asymptomatic patients. Consequently, this calls for careful evaluation and management of these masses to determine their nature and need for treatment. This article reviews current literature regarding the evaluation and management of SRM. It focuses on the specific use of MRI in the diagnosis and management of SRM. A Medline review of the literature was performed from 1996 to the present time. Computed tomography (CT) imaging has been the investigation of choice for evaluating SRM. However, some remain difficult to determine their malignant or benign nature and remain indeterminate. In such cases, further imaging with magnetic resonance imaging (MRI) can be performed to evaluate the mass in more detail. It can also be used where CT is contraindicated and where active surveillance is the treatment of choice and radiation exposure is a concern. MRI is a useful tool in evaluating an indeterminate small renal mass. Accurate diagnosis and management of SRM require close collaboration between a urologist and radiologist to identify potentially malignant tumours to subsequently reduce mortality from renal cell cancer.