Focal Renal Lesions Research Articles

Diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound in renal focal lesions.

To investigate the diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound (CEUS) of focal renal lesions. Ninety eligible patients admitted were selected as the study subjects. The incidence rate of annular hyperenhancement in different benign and malignant focal lesions during angiography and the shape of annular enhancement were counted. The correlation between the occurrence of benign and malignant renal tumors and annular hyperenhancement and unenhanced areas was also analyzed. Capsule enhancement was observed in 56 cases, including 50 cases of malignant tumors (89.3%, 50/56) and 6 cases of benign tumors (10.7%, 6/56). Pearson correlation analysis showed that renal malignancy was positively associated with the occurrence of pseudocapsule ring hyperenhancement (γ = 0.489, P < 0.001). Benign and malignant renal tumors were positively correlated with the occurrence of non-enhancing areas (γ = 0.215, P = 0.042). The thickness and peak intensity of pseudocapsule ring enhancement in renal malignant tumors were significantly higher than those in benign tumors (all P < 0.001), while the time to peak was significantly lower than that in benign tumors (P < 0.001). The results of receiver operating characteristic (ROC) curve showed that the ring enhancement thickness, time to peak, and area under ROC curve of peak intensity of tumor reached more than 0.9. In CEUS, the pseudocapsule of focal renal lesions is a characteristic feature of renal malignant tumors, which can be used as a differential basis for benign and malignant tumors to improve the accuracy of benign and malignant renal tumors.

Comparison of sonographic and CT findings for the identification of renal nodules in dogs and cats.

Ultrasonography (US) and computedtomography(CT) are used to diagnose neoplastic and non-neoplastic focal renal lesionsindogsandcats; however, comparative studies between these two diagnostic tools are lacking. The aim of this retrospective, methods comparison study was to evaluate and compare the performance of US compared to CT in identifying at least one renal nodule in animals with confirmed focal renal lesions. Imaging studies of animals with uni- or bilateral renal nodules smaller than 3cm that underwent both US and CT andthathadapathologicallyconfirmeddiagnosiswere reviewed. Animals with renal cysts and infarcts were excluded. Recorded features for both modalitiesincludedthefollowing: shape, size, number, localization, margins, renal profile. For CT only, recordedfeaturesalsoincludedattenuation (HU) and pattern of enhancement. For US only,recordedfeaturesalsoincluded echogenicity, echostructure, and rate of visibility. Final diagnosis was obtained by cytology or histopathology. Using CT, lesions were identified in all 39 (100%) kidneys of 18 dogs and seven cats. Most lesions were multiple, cortical, well-defined, iso-attenuating (precontrast), hypo-attenuating, and moderately enhancing (postcontrast). Using US, lesions were identified in 29 of 39 (74%) kidneys. Overall, nine (31%) lesions were poorly visible; 10 (26%) kidneys appeared normal; in 17 (59%) organs, lesions' number was underestimated. Isoechoic, non-protruding lesions were difficult to identify by US. Ultrasonography underestimated renal lesions compared to CT in 59% of the kidneys (P=0.001). Final diagnoses included metastatic disease (n=16), infiltration by feline lymphoma (n=4), primary neoplasia (n=3), and non-neoplastic benign lesions (n=2).

Multimodality imaging evaluation of pseudotumors in chronic renal dysfunction: exposing the masquerade!

Focal renal lesions in the background of chronic kidney disease (CKD) present a diagnostic challenge. Contrast administration is usually avoided in such a setting, undermining the usefulness of computed tomography and magnetic resonance imaging. Focal regenerating nodules may occur in the background of CKD and closely mimic renal neoplasms. The aim of the present article was to highlight the salient manifestations of such CKD pseudotumors on different imaging modalities and also to depict the differentiating features from malignancy. Radiologists must be aware of the imaging appearance of this uncommonly talked about entity so as to avoid inadvertent surgery or cause undue anxiety to the patient.

Which criteria can be used to predict benignity in solid renal lesions lower-equal to 2cm?

To evaluate magnetic resonance imaging (MRI) criteria of solid renal lesions lower-equal to 2cm to differentiate benign and malignant tumors, using histopathology as gold standard. Three radiologists independently evaluated objective and subjective MRI criteria of focal renal lesions. A total of 105 nodules of patients who had MRI and histopathological results in our institution were included. Subjective criteria evaluated were signal on T2-weighted imaging, presence of microscopic and macroscopic fat, hemosiderin, hemorrhage, central scar, segmented inversion enhancement and enhancement type; objective criteria were gender, ADC value, heterogeneity on T2-weighted imaging and proportion of enhancement in late post-contrast phases. Finally, the readers classified the lesions in probably benign or malignant. Interobserver agreement was evaluated by the Gwet method, and the quantitative variables by intraclass correlation coefficients. To adjust the predictive model, the logistic regression model was used considering the benignity variable as outcome. A total of 26 nodules (24.5%) were benign and 79 (75.2%) were malignant, with size ranging from 7 to 20mm (median: 14mm). The most frequent subtype was papillary renal cell carcinoma (RCC) (35.2%), followed by clear-cell RCC (24.8%) and oncocytoma (12.4%). The univariate and multivariate analysis showed, among all categories evaluated, that microscopic fat (p: 0.072), intermediate (p: 0.004) and hyper-enhancement (p: 0.031) and female sex (p: 0.0047) had the best outcome for benignity, within odds ratios of 4.29, 5.75, 4.07 and 2.86, respectively. In small solid renal lesions lower-equal to 2cm, microscopic fat, moderate and hyper-enhancement and female sex were associated with benignity.

Evaluation of Cystic and Solid Renal Lesions with Contrast-Enhanced Ultrasound: A Retrospective Study.

Purpose Renal lesions are frequent random findings on CT, MRI, and conventional ultrasound. Since they are usually found accidentally, the respective examinations have not been performed optimally to provide a conclusive diagnosis, making additional multiphase contrast-enhanced examinations necessary. The aim of the study is to correlate CEUS findings with the final diagnosis and to determine whether it is a suitable method for the conclusive characterization of undetermined renal lesions. Materials and Methods All CEUS examinations of focal renal lesions performed at our institute between 2007 and 2014 were retrospectively examined. 437 patients with a total of 491 lesions and 543 examinations were included. 54 patients had bilateral lesions. One patient had three lesions in one kidney. Histology was available in 49 cases and follow-ups in 124 cases. The sensitivity, specificity, positive and negative predictive value as well as positive and negative likelihood ratios were calculated. Results There were 54 malignant and 437 benign lesions. The sensitivity and specificity were 0.981/0.954 overall, 1.000/0.956 for cystic lesions, 0.977/0.906 for solid lesions, and 0.971/0.071 for the histologically confirmed lesions. Bosniak classification was consistent in 289 of 301 lesions (96%). Only 12 lesions (3.9%) were falsely assessed as malignant. Conclusion CEUS is an appropriate method for the clarification of undetermined renal lesions. The characterization of cystic lesions according to Bosniak is adequately possible, especially for potentially malignant lesions (types III and IV).

Quality Assessment of CEUS in Individuals with Small Renal Masses-Which Individual Factors Are Associated with High Image Quality?

Obesity and bowel gas are known to impair image quality in abdominal ultrasound (US). The present study aims at identifying individual factors in B-mode US that influence contrast-enhanced US (CEUS) image quality to optimize further imaging workup of incidentally detected focal renal masses. We retrospectively analyzed renal CEUS of focal renal masses ≤ 4 cm performed at our center in 143 patients between 2016 and 2020. Patient and lesion characteristics were tested for their influence on focal and overall image quality assessed by two experienced radiologists using Likert scales. Effects of significant variables were quantified by receiver operating characteristics (ROC) curve analysis with area under the curve (AUC), and combined effects were assessed by binary logistic regression. Shrunken kidney, kidney depth, lesion depth, lesion size, and exophytic lesion growth were found to influence focal renal lesion image quality, and all factors except lesion size also influenced overall image quality. Combination of all parameters except kidney depth best predicted good CEUS image quality showing an AUC of 0.91 (p < 0.001, 95%-CI 0.863–0.958). The B-mode US parameters investigated can identify patients expected to have good CEUS image quality and thus help select the most suitable contrast-enhanced imaging strategy for workup of renal lesions.

Visualisation of focal renal lesions on ultrasound: A review of 518 lesions with contrast CT correlation.

Conventional ultrasound (US) is a common imaging investigation of the kidneys; however, the current diagnostic performance of US in the visualisation of focal renal lesions is unknown. This study was a retrospective sequential review of 518 focal renal lesions (FRLs) in 200 patients aged 50years or older who received an US of the kidneys followed by contrast-enhanced computed tomography (CECT). Patient's age ranged from 50 to 94years. The majority were hospital inpatients. 518 FRLs were identified on CECT ranging from 3 to 165mm (median 8mm). The majority of FRLs (96.1%) were benign. The visualisation rate of FRLs on US was size-dependent: <5mm, 10.2%; 5-9mm, 22.3 mm; 10-14mm, 48.0%; 15-19mm, 82.1%; and 20-24mm, 100%. The visualisation of simple cysts was 49.1% and hyperdense lesions 81.8%. Follow-up was available on 58% of lesions. Benign lesions generally remained stable. Seven patients had concerning heterogeneous hyperdense masses on CECT, and US had visualised six of these (85.7%). Visualisation of FRLs is size-dependent. High rate of visualisation is achieved once the lesion exceeds 15mm in size. Small FRLs are associated with a low rate of visualisation on ultrasound; however, they are rarely concerning. Hyperdense lesions on CECT that carry high suspicion of malignancy are associated with a high rate of US visualisation.

Performance of simultaneous multi-slice accelerated diffusion-weighted imaging for assessing focal renal lesions in pediatric patients with tuberous sclerosis complex.

Diffusion-weighted imaging (DWI) is a useful MRI technique to characterize abdominal lesions in children, but long acquisition times can lead to image degradation. Simultaneous multi-slice accelerated DWI is a promising technique to shorten DWI scan times. To test the feasibility of simultaneous multi-slice DWI of the kidneys in pediatric patients with tuberous sclerosis complex (TSC) and to evaluate the accelerated protocol regarding image quality and quantitative apparent diffusion coefficient (ADC) values compared to standard echoplanar DWI sequence. We included 33 children and adolescents (12 female, 21 male; mean age 10±5years) with TSC and renal cyst or angiomyolipoma on 3-tesla (T) MRI from 2017 to 2019. All studies included both free-breathing standard echoplanar DWI and simultaneous multi-slice DWI sequences. Subjective and quantitative image quality was evaluated using a predefined 5-point scale. ADC values were obtained for all renal cysts and angiomyolipomas ≥5mm. All statistical analysis was performed using Stata/SE v15.1. Simultaneous multi-slice DWI ADC values were slightly lower compared to standard echoplanar DWI for both renal cysts and angiomyolipomas (mean difference 0.05×10-3mm2/s, 95% confidence interval [CI] 0.40-0.50 and 0.024×10-3mm2/s, 95% CI 0.17-0.21, respectively, with P>0.1). Our results showed that renal lesions with ADC values >1.69×10-3mm2/s were all cysts, whereas lesions with values <1.16×10-3mm2/s were all angiomyolipomas. However, ADC values could not discriminate between lipid-rich and lipid-poor angiomyolipomas (P>0.1, for both sequences). A 55% reduction in scan time was achieved using simultaneous multi-slice DWI for abdominal imaging in children with TSC, with near identical image quality as standard DWI. These results suggest that multi-slice techniques should be considered more broadly as an MRI acceleration technique in children.

Distinguishing Renal Cell Carcinoma From Other Focal Renal Lesions on Multidetector Computed Tomography

Background: The increased use of imaging modalities has led to a greater incidence in depicting solid renal mass. These lesions comprise a wide spectrum of malignant such as renal cell carcinoma (RCC) and benign histologies.&#x0D; Objective: To determine the multidetector computed tomography (MDCT) features that discriminate RCC from other focal renal lesions.&#x0D; Methods: A retrospective review was performed on 148 patients who underwent renal CT scan followed by renal surgery or biopsy during January 2008 to July 2014. Specific predictive MDCT features of RCC were determined by logistic regression analysis. Interobserver agreement (kappa [K] values) was also calculated for each CT feature.&#x0D; Results: In 148 pathologic proved focal renal lesions, 91 (61.5%) were RCCs and 57 (38.5%) were non-RCCs. RCCs were more likely to be in male patients (OR, 5.39; 95% CI, 2.25 - 12.90), no internal fat component (OR, 46.50; 95% CI, 5.25 - 411.90), locate at peripheral (OR, 7.41; 95% CI, 1.63 - 33.73), and mixed central-peripheral locations (OR, 26.22; 95% CI, 4.23 - 162.58) of the kidney. There was moderate-to-excellent agreement among the readers over all these features (K = 0.43 - 0.91).&#x0D; Conclusions: Focal renal lesion with no internal fat component in MDCT is the most useful characteristic in differentiating RCCs from others.&#x0D;

European Society of Paediatric Radiology abdominal imaging task force: recommendations for contrast-enhanced ultrasound and diffusion-weighted imaging in focal renal lesions in children.

Contrast-enhanced ultrasound (CEUS) and diffusion-weighted imaging (DWI) are safe, repeatable imaging techniques. The aim of this paper is to discuss the advantages, technical factors and possible clinical applications of these imaging tools in focal renal lesions in children.

Common pitfalls in renal mass evaluation: a practical guide.

More than half of patients over 50 years of age have had at least one focal renal lesion detected as an incidental finding during an ultrasound, computed tomography, or magnetic resonance imaging examination. Although the majority of such lesions can be easily detected and correctly characterized, misdiagnoses may occur and are often related to methodological limitations, inappropriate imaging protocols, or misinterpretation. This pictorial essay provides recommendations on how to recognize benign and malignant renal processes that can be potentially missed or mischaracterized in imaging studies.

3:00 PM Abstract No. 91 Population-based analysis of percutaneous renal biopsies: complications, utilization, and predictors of outcomes

Percutaneous renal biopsies are commonly performed minimally invasive interventions to determine etiologies of renal failure and characterize focal renal lesions. Data regarding utilization and outcomes for these procedures are generally limited to retrospective series from high volume centers. The purpose of this study was to establish population-based measurements for percutaneous renal biopsy procedure complications and their risk factors. Using administrative data from all inpatient and outpatient hospital encounters in California (2009-2011), patients undergoing percutaneous renal biopsies were identified. The demographic characteristics of this patient cohort as well as risk factors for complications were analyzed. 14,973 percutaneous renal biopsies were performed in 13,372 patients during the study period. Comorbidities included renal failure (35.1%), hypertension (58.8%), atherosclerosis (8.7%), diabetes (20.5%), obesity (10.0%), congestive heart failure (9.6%), coagulopathy (6.9%), and malignancy (11.7%). Biopsies were performed across 282 hospitals, with yearly procedural volumes ranging from 1 to 312.6. Of the 4, 796 patients who underwent biopsies as outpatients, 183 patients (3.8%) had unscheduled hospital visits within 7 days of the procedure with a median length of stay of 3 days (range, 0 - 68 days). Post-biopsy hemorrhage was identified in 6.1% of patients undergoing biopsy, and 1.8% of patients required blood transfusions within 30 days of the biopsy. The all cause 30-day inpatient mortality rate was 2.8%. History of renal failure (OR 1.03 [1.01 – 1.05]) and hypertension (OR 1.02 [1.00 -1.04]) were significantly associated with post-biopsy hemorrhage, and history of renal failure (OR 1.03 [1.01 – 1.04]), hypertension (OR 1.03 [1.02 – 1.05]), and diabetes (OR 1.02 [1.00 – 1.03]) were significantly associated with - day unscheduled hospitalization. Percutaneous renal biopsies are a commonly performed procedure with low complication risks. These population-level estimates should help establish patient and physician expectations as well as societal guidelines for complication rate thresholds.

Comparison of MDCT, MRI and MRI with diffusion-weighted imaging in evaluation of focal renal lesions: The defender, challenger, and winner!

Purpose:To compare the diagnostic performance of multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and MRI with diffusion-weighted imaging (DWI) in the characterization of focal renal lesions. We also compared MDCT and MRI in the staging of renal cell carcinoma (RCC).Materials and Methods:One hundred and twenty adult patients underwent MDCT (40-row and 128-row scanners), MRI (at 1.5 T), and DWI (at b-values of 0 and 500 s/mm2) for characterization of 225 renal lesions. There were 65 malignant neoplasms (44 RCCs), 25 benign neoplasms, 25 abscesses, 45 pseudotumors, 15 hemorrhagic cysts, and 50 benign cysts. A composite gold standard including histology, typical imaging criteria, and follow-up imaging was employed. To determine the diagnostic performance of imaging modalities, area-under-curve (AUC) was calculated by receiver-operating-characteristic analysis and compared. Fisher's exact test was used to compare the diagnostic accuracies and confidence levels with MDCT, MRI, and MRI + DWI. Cross-tabulation was used to assess the precision of MDCT and MRI in RCC staging.Results:AUC for MDCT (0.834) and MRI (0.841) in the classification of benign and malignant lesions were within corresponding 95% confidence interval (CI) (P = 0.88) whereas MRI + DWI had significantly better performance (AUC 0.968, P = 0.0002 and 0.0004, respectively). Both CT and MRI had low specificity (66.9% and 68.8%, respectively), which increased substantially with DWI (93.8%) owing to correct diagnosis of pseudotumors. MRI was superior to CT in diagnosing necrotic RCC and hemorrhagic cysts. MRI + DWI had the highest accuracy (94.2%) in assigning the definitive diagnosis and 97.6% lesions were diagnosed with very high confidence, significantly better than CT and MRI. Both CT and MRI had the same accuracy (86.1%) in RCC staging and evaluation of intravascular thrombi.Conclusions:Characterization of renal lesions was most accurate with MRI + DWI. The latter is also the most suitable modality in diagnosing pseudotumors and evaluating patients with renal dysfunction. CT and MRI were equivalent in RCC staging.

How (not) to misdiagnose focal renal lesions: lessons learned?

More than half of patients over the age of 50 years old may have at least one incidental renal lesion detected on imaging studies, such as ultrasonography, computed tomography or magnetic resonance imaging. Although the majority can be easily detected and correctly characterized, misdiagnoses may occur and are often related to methods limitations, inadequate imaging protocols and misinterpretation. This pictorial essay addresses recommendations on how to recognize benign and malignant renal processes that can be potentially missed or mischaracterized on imaging studies.

Chemical shift magnetic resonance imaging for distinguishing minimal-fat renal angiomyolipoma from renal cell carcinoma: a meta-analysis.

To determine the performance of chemical shift signal intensity index (CS-SII) values for distinguishing minimal-fat renal angiomyolipoma (mfAML) from renal cell carcinoma (RCC) and to assess RCC subtype characterisation. We identified eligible studies on CS magnetic resonance imaging (CS-MRI) of focal renal lesions via PubMed, Embase, and the Cochrane Library. CS-SII values were extracted by lesion type and evaluated using linear mixed model-based meta-regression. RCC subtypes were analysed. Two-sided p value <0.05 indicated statistical significance. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Eleven articles involving 850 patients were included. Minimal-fat AML had significantly higher CS-SII value than RCC (p < 0.05); there were no significant differences between mfAML and clear cell RCC (cc-RCC) (p = 0.112). Clear cell RCC had a significantly higher CS-SII value than papillary RCC (p-RCC) (p < 0.001) and chromophobe RCC (ch-RCC) (p = 0.045). The methodological quality was relatively high, and Begg's test data points indicated no obvious publication bias. The CS-SII value for differentiating mfAML from cc-RCC remains unproven, but is a promising method for differentiating cc-RCC from p-RCC and ch-RCC. • RCC CS-SII values are significantly lower than those of mfAML overall. • CS-SII values cannot aid differentiation between mfAML and cc-RCC. • CS-SII values might help characterise RCC subtypes.

Characterization of Small (< 4 cm) Focal Renal Lesions: Diagnostic Accuracy of Spectral Analysis Using Single-Phase Contrast-Enhanced Dual-Energy CT.

The purpose of this study is to determine whether single-phase contrast-enhanced dual-energy quantitative spectral analysis improves the accuracy of diagnosis of small (< 4.0 cm) renal lesions, compared with conventional single-energy attenuation measurements. In this retrospective study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign and 33 malignant) underwent single-energy unenhanced and dual-energy contrast-enhanced CT of the abdomen. For each renal lesion, attenuation measurements were obtained, and an attenuation change of 15 HU or greater was considered evidence of enhancement. Dual-energy spectral attenuation curves were generated for each lesion. The slope of each curve was measured between 40 and 50 keV (λHU40-50), 40 and 70 keV (λHU40-70), and 40 and 140 keV (λHU40-140). Mean lesion attenuation values and spectral attenuation curve parameters were compared between benign and malignant renal lesions by use of the two-sample t test. Diagnostic accuracy was assessed and validated using cross-validation analysis. With the use of cross-validated optimal thresholds at 100% sensitivity, specificity for differentiating between benign and malignant renal lesions improved significantly when both λHU40-70 and λHU40-140 were used, compared with conventional enhancement measurements (93% [103/111; 95% CI, 86-97%] vs 81% [90/111; 95% CI, 73-88%]) (p = 0.02). The sensitivity of λHU40-70 and λHU40-140 was also higher than that of conventional enhancement measurements, although it was not statistically significant. Single-phase contrast-enhanced dual-energy quantitative spectral analysis significantly improves the specificity for characterization of small (< 4.0 cm) renal lesions, compared with conventional single-energy attenuation measurements.

Distinctive inflammatory profile between acute focal bacterial nephritis and acute pyelonephritis in children

BackgroundAcute focal bacterial nephritis (AFBN) is a severe form of upper urinary tract infection (UTI) with neurological manifestations and focal renal mass lesions on computed tomography (CT). Prolonged antibiotic therapy may improve the renal outcome, but the early differential diagnosis of AFBN from acute pyelonephritis (APN) is challenging. We searched for effective biomarkers of AFBN based on the pathophysiology of upper UTIs. MethodsOf 52 upper UTI cases treated at Yamaguchi University between 2009 and 2016, 38 pediatric patients with AFBN (n=17) or APN (n=21) who underwent ultrasonography and/or CT were enrolled. The clinical data and serum cytokine concentrations were analyzed to differentiate AFBN from APN. ResultsAFBN patients tended to be older, and have a higher body temperature, longer febrile period, more frequent neurological symptoms, higher immature neutrophil count, lower lymphocyte count, higher procalcitonin and urine β2-microglobulin levels. AFBN patients showed higher serum levels of IFN-γ, IL-6, IL-10 and soluble TNF-receptor 1 (sTNFR1) (all p<0.05). Although the cytokine levels were variably correlated among each other, multiple logistic regression analysis revealed that combination of IFN-γ and IL-6 levels were most relevant for distinguishing AFBN from APN. The discriminant power of the logistic equation was 0.86 in terms of the area under the curve by the ROC analysis. ConclusionsCirculating 4 out of 7 cytokines in AFBN patients were at higher levels compared with those in APN patients. IFN-γ and IL-6 levels might most effectively distinguish AFBN from APN.

The role of magnetic resonance diffusion tensor imaging in differentiation of benign from malignant focal renal lesions

Amac: Fokal bobrek lezyonlarinin benign, malign ayiriminda gorunusteki difuzyon katsayisi (apparent diffusion coefficient - ADC) ve fraksiyonel anizotropi (Fa) olcumlerinin diagnostik performanslarinin belirlenmesi. Gerec ve Yontem: Calismamiza, bilgisayarli tomografi (BT) ve ultrason (US) gibi degisik goruntuleme modaliteleri ile tani konulan ve manyetik rezonans diffuzyon tensor goruntulemesi (DTI) yapilmis 21 hastada (9 kadin and 12 erkek ; ortalama yas 54,1 ), 25 fokal renal lezyon dahil edildi. Lezyonlar 6 solid renal hucreli karsinom (RCC), 1 kistik RCC, 1 anjiomyolipom (AML) ve 17 kistik lezyondan ( 16 Bosniak tip I kist, 1 Bosniak tip II kist) olusmaktaydi. ADC ve Fa olcumleri iki radyolog tarafindan, konsensusa varilarak yapildi. Malign ve benign lezyonlara ait ADC ve Fa degerleri ANOVA ve Tukey testleri kullanilarak karsilastirildi. ROC analizi kullanildi; sensitivite ve spesifite hesaplandi. Bulgular: Malign lezyonlarin ortalama ADC ve Fa degerleri sirasiyla 1.29±0.4 mm2/sn ve 0.34±0.1 olculdu. Benign lezyonlarin ortalama ADC ve Fa degerleri sirasiyla 2.6±0.7 mm2/sn ve 0.19±0.12 olculdu. Aralarindaki fark istatistiksel olarak anlamli idi (P<0.05). Malign lezyonlari, benign lezyonlardan ayirmada ADC ve Fa olcumlerinin, Az degerleri sirasiyla 0.95 ve 0.83 bulundu. ADC ve Fa olcumlerinin sensitivite ve spesifite degerleri sirasiyla 100%-83.3% ve 100%-77.8% bulundu. Sonuc: Malign ve benign fokal renal lezyonlarin ADC ve Fa olcumleri degerleri arasinda istatistiksel anlamli farklar mevcuttur. Malign renal lezyonlarda dusuk ADC ve yuksek Fa degerleri izlenirken, benign renal lezyonlarda yuksek ADC ve dusuk Fa degerleri izlenir.

Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements. © RSNA, 2017 Online supplemental material is available for this article.

The role of contrast-enhanced ultrasound in the classification of CT-indeterminate renal lesions

Objective: Focal renal lesions are common incidental findings on computed tomography (CT). For lesions with a cystic appearance, the Bosniak classification system has enabled an important separation of benign and (potentially) malignant cysts, giving a practical guide for management. The purpose of this study was to evaluate contrast-enhanced ultrasound (CEUS) as a problem-solving modality for classification of indeterminate renal lesions detected with CT.Materials and methods: In total, 140 consecutive patients with 148 indeterminate renal lesions were examined with ultrasound combined with CEUS (81 men and 59 women with mean age 63.8 years).Results: Altogether, 146 lesions were classified by CEUS in categories according to the Bosniak classification system, or as solid lesions. Mean lesion diameter was 30 mm (range 5–166 mm). Nine lesions were classified as category I, 32 as category II and 59 as category IIF (“non-surgical lesions”). 48 IIF cysts were followed for a minimum of 2 years (mean 4 years and 8 months): three lesions were upgraded to category III (6%) and 45 were stable category. 19 lesions had a more complex cystic appearance: 12 were classified as category III and seven as category IV cysts. 27 lesions were diagnosed as solid, enhancing tumors. In total, 25 patients with lesions of category III, IV and solid (“surgical lesions”) underwent renal surgery, with malignancy diagnosed in 18.Conclusion: In the common setting of indeterminate renal lesions incidentally detected with a CT exam, CEUS has the potential to classify lesions into “non-surgical” and “surgical” categories, providing a platform for urological decision making, while avoiding radiation exposure.