Utility of Shear Wave Elastography for Assessing Allograft Fibrosis in Renal Transplant Recipients: A Pilot Study.

OBJECTIVES: To evaluate the utility of ultrasound-based shear wave elastography (SWE) as a noninvasive method to accurately detect and potentially stage the severity of renal allograft fibrosis and assess its user reproducibility. METHODS: In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant prospective study, 70 renal transplant recipients underwent an SWE evaluation of their allograft followed directly by biopsy. Two radiologists performed separate SWE measurement acquisitions and the mean, median, and standard deviation of 10 SWE measurements, obtained separately within the cortex and the medulla, were automatically computed. Each patient's SWE results were subsequently compared to their histologic fibrosis scores. The Fisher exact test and univariate logistic regression models were fit to test for associations between the presence of fibrosis (yes/no) as well as categorical SWE results based on the fibrosis severity, ranging from F0 (no fibrosis) to F3 (severe fibrosis), correlating with histologic scores according to the 2007 Banff classification system. Interobserver and intraobserver correlations were also examined. RESULTS: Our median medulla SWE values reached statistical significance (P = .04) in association with fibrosis. Furthermore, for every unit increase in the median medulla SWE measurement, the odds of fibrosis increased by approximately 20%. No statistical significance was found for mean cortical, median cortical, or mean medullary SWE values (P = .32, .37, and .06, respectively) in association with fibrosis. CONCLUSIONS: The use of SWE for assessing renal allograft fibrosis is challenging but promising. Further investigation with a larger sample size remains to validate our initial results and establish clinical relevance.

Pitfalls of Sonographic Imaging of Uterine Leiomyoma.

Leiomyomas are the most common uterine tumor and the most common cause of uterine enlargement in the nonpregnant patient. Sonography is the imaging modality of choice for the initial diagnosis and imaging workup of uterine leiomyomas and is also extremely helpful in determining the etiology of a broad range of pelvic symptoms in the female patient. Although the classic sonographic appearance of uterine leiomyomas is well established and easily recognizable, other pelvic masses may occasionally be confused with uterine leiomyomas, and the ability to distinguish between these entities is crucial in optimizing appropriate patient care. This article will review pelvic abnormalities that can be confused on ultrasound with uterine leiomyomas and potential methods that can be used to avoid these pitfalls.

Renal Cell Carcinomas: Sonographic Appearance Depending on Size and Histologic Type.

OBJECTIVES: Prior studies have demonstrated that approximately 10% of malignant renal cell carcinomas are as echogenic as angiomyolipomas on sonography. However, a recent presentation suggested that small (<1-cm) echogenic renal masses are always angiomyolipomas or other benign entities. We therefore examined our own cases of renal cell carcinoma, with corresponding sonography, to confirm that some renal cell carcinomas may also be detected as hyperechoic masses on sonography. METHODS: Institutional Review Board approval and Health Insurance Portability and Accountability Act compliance were maintained for this retrospective review of 91 pathologically proven cases of renal cell carcinoma, with corresponding sonography. Tumors were first differentiated by histologic cell type (clear cell, papillary, and chromophobe). Tumors were then stratified according to 2 size group parameters, falling into those that were 3 cm or larger and those that were smaller than 3 cm in diameter, with the less than 3-cm group further subdivided into 2 cm or smaller and greater than 2 cm. Tumor echogenicity was graded on a 5-point scale with respect to the renal parenchyma. RESULTS: Forty-six tumors (51%) were 3 cm in diameter or smaller, and most were found to be either isoechoic (35%) or mildly hyperechoic (26%) to the surrounding renal parenchyma. Of tumors smaller than 2 cm, most were either mildly hyperechoic (29%) or as hyperechoic as renal sinus fat (very hyperechoic; 29%). Tumors larger than 3 cm were found most often to be either isoechoic (49%) or mildly hyperechoic (33%), with only 4% found to be very hyperechoic. CONCLUSIONS: The sonographic appearances of renal cell carcinomas include a small population that are very hyperechoic on sonography and thus could potentially be misdiagnosed as angiomyolipomas.