Should We Biopsy Complex Cystic Renal Masses (Bosniak Category III)?

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.

Multilocular Cystic Nephroma: A Systematic Literature Review of the Radiologic and Clinical Findings

OBJECTIVE

The objective of our study was to systematically summarize the published evidence of demographic, clinical, diagnostic imaging, and therapeutic characteristics of patients with multilocular cystic nephroma (MLCN).

CONCLUSION

Cross-sectional imaging evaluation is important for suggesting the diagnosis of MLCN but has several limitations. The number of radical nephrectomies reported for MLCN encourages discussion concerning the utility of percutaneous presurgical biopsy and frozen-section intraoperative biopsy as a more conservative diagnostic approach.

Journal club: Renal masses detected at abdominal CT: radiologists' adherence to guidelines regarding management recommendations and communication of critical results

OBJECTIVE

The purpose of this study was to assess radiologists' adherence to published guidelines for managing renal masses detected at abdominal CT at one institution and to a critical results communication policy.

MATERIALS AND METHODS

A validated natural language processing tool supplemented by manual review was used to randomly assemble a cohort of 97 radiology reports from all abdominal CT reports (n = 11,952) generated from July 2010 to June 2011. Critical renal mass findings warranted consideration for surgery, intervention, or imaging follow-up and required direct, separate, and timely communication to the referrer in addition to the radiology report. Primary outcomes were adherence to guidelines and institutional policy for communicating critical results. Sample size allowed a 95% CI ± 5% for primary outcome. Pearson chi-square test was performed to assess whether radiology subspecialization was predictive of the primary outcome.

RESULTS

Of all abdominal CT reports, 35.6% contained at least one renal mass finding (4.3% critical). Guideline adherence was lower for patients with critical than for those with noncritical findings (48/57 [84.2%] vs 40/40 [100%]; p = 0.01). Adherence to critical result communication policy was 73.7% (42/57). For critical findings, abdominal radiologists had higher guideline adherence (40/43 [93.0%] vs 8/14 [57.1%]; p = 0.001) and critical result communication policy adherence (36/43 [83.7%] vs 6/14 [42.9%]; p = 0.002) than nonabdominal radiologists.

CONCLUSION

In reporting renal masses detected at abdominal CT, radiologists largely adhered to management guidelines but did not adhere to the critical results communication policy in one of four reports. Subspecialization improved adherence to both management guidelines and the institution's critical result communication policy.

Imaging techniques for the patient with renal cell carcinoma

The imaging of renal cell carcinoma continues to evolve from radiographic tomography to state-of-the-art three-dimensional imagery using computed tomography (CT) or magnetic resonance imaging (MRI). This article reviews the current techniques of imaging the patient with renal cell carcinoma. Careful and accurate imaging of these patients allows for the appropriate diagnosis, treatment planning, and follow-up care. At each point in the care of these patients, imaging plays an important role. In particular, the diagnosis and staging of renal cell carcinoma can be accomplished with CT and MRI, with each modality having strengths and weaknesses that are contrasted. Intraoperative ultrasound is used during laparoscopic or conventional partial nephrectomies, whereas ultrasound, CT, and MRI can be used for guiding ablative technologies. Imaging also plays an important role in the follow-up care of these patients. The particular follow-up care is dependent on the stage and grade of the lesion and the treatment modality used. In summary, this article reviews the current imaging approaches for the diagnosis, staging, treatment, and follow-up care of patients with renal cell carcinoma.

Complex cystic renal masses: characterization with contrast-enhanced US

PURPOSE

To prospectively compare contrast material-enhanced ultrasonography (US) with computed tomography (CT) in the classification of complex cystic renal masses with the Bosniak system.

MATERIALS AND METHODS

Ethics committee approval and written informed consent were obtained. Forty patients (17 women, 23 men; age range, 31-77 years) with 44 complex cystic renal masses detected with conventional US were prospectively examined by using second-harmonic US with a second-generation contrast agent and multiphasic helical CT. Thirty-six patients had one lesion, and four patients had two lesions. Surgical resection in nine patients and imaging follow-up in 31 patients were used to determine the outcome.

RESULTS

On contrast-enhanced US images, masses were classified as Bosniak category II (n = 18), IIF (ie, lesions were classified as category II and follow-up was needed) (n = 16), III (n = 7), or IV (n = 3) lesions. On CT images, masses were classified as Bosniak category II (n = 24), IIF (n = 10), III (n = 7), or IV (n = 3) lesions. Interobserver agreement was high (kappa = 0.86, P < .001) for classification with US. Complete concordance between the readers was found for classification with CT. Complete concordance between contrast-enhanced US and CT was observed in the differentiation of surgical and nonsurgical complex cysts. Complete concordance among the three readers in the assessment of vascularity with contrast-enhanced US was found. Interobserver agreement in the evaluation of enhancement on CT images was high (kappa = 0.88, P < .001). Concordance between contrast-enhanced US and CT in the evaluation of vascularization was high (kappa = 0.77, P < .001).

CONCLUSION

The study data suggest that contrast-enhanced second-harmonic US is appropriate for renal cyst classification with the Bosniak system.

Renal Mass Core Biopsy: Accuracy and Impact on Clinical Management

OBJECTIVE

The objective of our study was to determine the accuracy of imaging-guided percutaneous renal mass biopsy and its impact on clinical management.

MATERIALS AND METHODS

With institutional review board approval, we retrospectively reviewed imaging-guided renal biopsies performed by radiologists at our institution between February 1999 and July 2005. Patient records, pathology reports, and imaging studies were reviewed. Concordance of biopsy diagnosis and follow-up data was assessed. Significant impact on clinical management was determined in collaboration with two experienced urologists and was defined as a change from no therapy to therapy, including surgery, tumor ablation, chemotherapy, or radiation.

RESULTS

Two hundred seventy-six renal biopsies were performed during the study period. Of these, 123 were random biopsies and fine-needle technique was used for one; these 124 were excluded. One hundred fifty-two renal mass biopsies were performed using coaxial 18-gauge core needle technique in 125 patients (55 women, 70 men; average age, 60 years; range, 28-90 years). There were two (1.3%) postprocedural hematomas (one [0.7%] requiring blood transfusion) and one (0.7%) delayed renal pseudoaneurysm attributed to biopsy. No tumor seeding was identified. In 85 biopsies (56%), malignant neoplasm was found, 61 biopsies (40%) yielded benign findings, and six (4%) were nondiagnostic. The sensitivity for malignancy was 97.7%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 100%. At least 92 (60.5%) biopsy results significantly impacted clinical management.

CONCLUSION

Imaging-guided percutaneous core needle biopsy of renal masses is safe and highly accurate. Tissue diagnosis alters clinical decision making in a majority of the cases and may allow a number of unnecessary nephrectomies to be avoided.

From the RSNA Refresher Courses

The pathologic and imaging features of the renal cyst have been well described. A fluid-filled lesion is considered a cystic mass (ie, not a simple cyst) when it has any of the following features: calcification, high attenuation (>20 HU) at computed tomography, signal intensity not typical of water at magnetic resonance imaging, septations, multiple locules, enhancement, wall thickening, or nodularity. There are two important causes of a cystic renal mass: a complicated simple cyst (eg, one with hemorrhage, infection, or ischemia) and cystic renal cell carcinoma. At radiologic evaluation of such masses, it is imperative that optimal imaging techniques be used. Masses with calcification, high attenuation or high signal intensity, or septations can be categorized as benign (no further evaluation required), as requiring follow-up (probably benign), or as requiring surgery. Lesions requiring surgery can be benign or malignant at microscopic examination. Lesions that are multiloculated or demonstrate enhancement, wall thickening, or nodularity usually require surgery. When multiple features are present (eg, calcification and enhancement), the mass should be managed according to its most aggressive feature. Likewise, when there are conflicting findings at evaluation with different imaging modalities, the mass should be managed according to the most aggressive finding.