Li-Yun Xue

Contrast-enhanced ultrasonography for evaluation of cystic renal mass: in comparison to contrast-enhanced CT and conventional ultrasound

AbsractPurposeTo assess the value of contrast-enhanced ultrasonography (CEUS) in evaluating cystic renal lesions compared with conventional ultrasound (US) and contrast-enhanced computed tomography (CECT).MethodsOne hundred and three patients with complex cystic renal masses underwent preoperative US and CEUS, among which 70 conducted CECT at our institution. The images were analyzed with the number of septa, septa and wall thickness and the presence of solid component, and final diagnosis was made.ResultsIn malignancies, CEUS demonstrated more septa, thicker wall or septa, and more solid components than US and CECT. CEUS permitted categorization of 51.7% (30/58) and 28.6% (10/35) of malignant tumors in higher grade than by US and CECT, respectively. In benign lesions, CEUS detected more septa than CECT and correctly diagnosed benign cysts which appeared as solid lesions in US. CEUS permitted downgrading of 71.1% (32/45) and 17.1% (6/35) of benign lesions compared to US and CECT. The diagnostic performance of CEUS was better than US for benign cystic lesions. The phenomenon that solid-like component by US did not enhance by CEUS was a strong predictor of benign disease, with a positive predictive value (PPV) of 100%. Enhancement of solid, soft tissue by CEUS was highly predictive of malignancy, with a PPV of 100%.ConclusionsCEUS was superior to US and CECT in visualizing the number of septa septa and wall thickness, and the presence of solid component of cystic renal lesions. CEUS may play a similar role to CECT in the diagnosis of renal cystic lesions, and better than US.

Evaluation of renal urothelial carcinoma by contrast-enhanced ultrasonography.

PURPOSE To observe ultrasonographic features of urothelial carcinoma in renal pelvis and evaluate contrast-enhanced ultrasound (CEUS) in diagnosis. MATERIALS AND METHODS Fifty-two patients with urothelial carcinoma underwent preoperative conventional US, colour Doppler flow imaging (CDFI) and CEUS. RESULTS Of 52 total lesions, 41 (78.8%) could be clearly identified by US, and 49 (94.2%) were enhanced by CEUS. Among US-imaged lesions, 39 (95.1%) were solid tumours, and two (4.9%) were mixed solid-cystic; 25 (61.0%) were isoechoic, 11 (26.8%) hypoechoic, and five (12.2%) hyperechoic. Analysis of tumour blood flow by CDFI characterised 17 avascular lesions (41.5% of total), 16 hypovascular (39.0%), and 8 hypervascular (19.5%). The resistance index ranged from 0.65 to 0.88 (mean of 0.71). Enhancement was seen in 49 lesions after injection of SonoVue. A slow enhancement pattern was observed in 36 lesions (73.5%) relative to renal cortex, and 13/49 (26.5%) showed simultaneous enhancement. At peak enhancement, 38 lesions (77.6%) were hypo-enhanced, six (12.2%) iso-enhanced, and five (10.2%) hyper-enhanced. There were 12 lesions with intertumoural necrosis or haemorrhage (24.5%) that were heterogeneously enhanced, and 37 (75.5%) were homogeneously enhanced. A fast washout pattern was observed in 46 lesions (93.9%), synchronous washout in two (4.08%), and slow washout in one (2.04%). CONCLUSIONS Slow-in, fast-out, and hypo-enhancement properties are associated with renal urothelial carcinoma and may thus have diagnostic value. We found that CEUS is able to identify tumours that are ambiguous by conventional US, and it thus significantly improves the confidence of diagnosis.

Papillary renal cell carcinoma and clear cell renal cell carcinoma: Differentiation of distinct histological types with contrast - enhanced ultrasonography

PURPOSE Papillary renal cell carcinoma (pRCC) and clear cell renal cell carcinoma (ccRCC) have different biological behaviours and imaging features. The role of contrast-enhanced ultrasound (CEUS) in differentiating these two carcinoma subtypes has not been comprehensively studied. MATERIALS AND METHODS Forty-eight patients with 49 pRCC lesions and 153 patients with 156 ccRCC lesions underwent preoperative conventional ultrasound (US) and CEUS. Among them, 91 patients (25 pRCCs and 66 ccRCCs) also underwent preoperative contrast-enhanced computed tomography (CECT) in our hospital. The characteristics of CEUS and CECT images for each patient imaged were analysed by each of two blinded observers. RESULTS Images for five (5/25, 20%) pRCC patients demonstrated equivocal or no enhancement using CECT, while all lesions were enhanced using CEUS. From CEUS, images of pRCCs, when compared with ccRCC images, demonstrated significantly higher frequencies of slow wash-in (59.2% vs. 5.8%), fast wash-out (87.7% vs. 46.1%), and hypo-enhancement (57.1% vs. 7.1%) patterns, p<0.001, as well as the presence of pseudocapsule (42.9% vs. 23.1%), p=0.007. For lesions with large diameters (> 3 cm), a higher percentage of pRCC images demonstrated homogeneous enhancement compared with ccRCC images. Using the combination of slow wash-in, fast wash-out, and hypoenhancement patterns at peak as criteria to differentiate pRCC from ccRCC, positive and negative predictive value, and sensitivity and specificity were found to be 86.7%, 86.9%, 53.1%, and 97.4%, respectively. CONCLUSIONS CEUS imaging features of slow-in, fast-out, and hypo-enhancement patterns may be useful for differentiating pRCC and ccRCC. In addition, CEUS may be helpful for diagnosing hypovascular renal lesions that demonstrate equivocal or no enhancement by CECT and, thus, for improving diagnostic confidence.

Non-invasive Assessment of Liver Fibrosis in a Rat Model: Shear Wave Elasticity Imaging Versus Real-Time Elastography

The purpose of this study was to investigate the diagnostic value of shear wave elasticity imaging (SWEI) and real-time elastography (RTE) in liver fibrosis induced by dimethylnitrosamine (DMN) and to compare the accuracy of these methods. Seventy male Wistar rats given a single intra-peritoneal injection of DMN and 10 control rats given a saline injection underwent SWEI and RTE to determine their shear wave velocity (V(s)) and liver fibrosis (LF) index, respectively. Correlations between V(s) or the LF index and histologic stage of liver fibrosis (S0-S4) were analyzed, and the diagnostic values of the techniques were assessed using a receiver operating characteristic curve. A positive correlation was found between V(s) and stage of liver fibrosis (r = 0.947, p < 0.001) and between LF index and stage (S) of liver fibrosis (r = 0.662, p < 0.001). For Vs, the areas under the receiver operating characteristic curve for the diagnosis of fibrosis, S ≥ S1, S ≥ S2, S ≥ S3 and S = S4, were 0.983, 0.995, 0.999 and 0.964, respectively; for the LF index, the values were 0.871, 0.887, 0.761 and 0.839, respectively (all p < 0.001). Vs and the LF index values in rats with severe inflammatory activity were significantly higher than those in controls (p < 0.001). In conclusion, positive correlations exist between V(s) or the LF index and the severity of liver fibrosis in rats. Vs is more accurate than the LF index in predicting liver fibrosis in rats. However, severe inflammatory activity may reduce the accuracy of both techniques.

Differentiation of Renal Tumor Histotypes: Usefulness of Quantitative Analysis of Contrast-Enhanced Ultrasound

OBJECTIVE The purpose of this study is to evaluate quantitative analysis of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of renal tumor histotypes. MATERIALS AND METHODS Between January 2010 and December 2013, 106 clear cell renal cell carcinomas (RCCs) (mean [± SD] diameter, 3.7 ± 1.8 cm), 34 angiomyolipomas (mean diameter, 4.1 ± 1.4 cm), 25 papillary RCCs (mean diameter, 3.5 ± 1.1 cm), and 28 chromophobe RCCs (mean diameter, 2.9 ± 0.9 cm) underwent CEUS quantitative analysis. The dynamic vascular pattern was analyzed with the Fisher exact chi-square test, and rise time, time to peak (TTP), and tumor-to-cortex enhancement ratio were analyzed with the independent-sample t test. RESULTS Dynamic vascular pattern types I and III (hyperenhancement) were more common among clear cell RCCs, whereas type II (hypoenhancement) was more common among angiomyolipomas, papillary RCCs, and chromophobe RCCs. Irrespective of dynamic vascular pattern class, the rise time and TTP were the shortest in clear cell RCCs and were equal in angiomyolipomas, papillary, and chromophobe RCCs. The tumor-to-cortex enhancement ratio was the highest in clear cell RCCs, was second highest in angiomyolipomas, and was lowest but equal in papillary and chromophobe RCCs. Clear cell RCCs and angiomyolipomas accounted for the majority of the hyperenhancing group. The tumor-to-cortex enhancement ratio of clear cell RCCs was higher than that of angiomyolipomas. With tumor-to-cortex enhancement ratio greater than 146.0% as the cutoff to differentiate clear cell RCC from angiomyolipoma in the hyperenhanced group, the sensitivity and specificity were each 71.4%. In the hypoenhanced group, the tumor-to-cortex enhancement ratio was the same in clear cell RCCs and angiomyolipomas but was higher in papillary and chromophobe RCCs. With tumor-to-cortex enhancement ratio greater than 54.2% as the cutoff point to differentiate clear cell RCCs from papillary and chromophobe RCCs, the sensitivity and specificity were 95.5% and 94.8%, respectively, whereas with a tumor-to-cortex enhancement ratio greater than 57.4% as the cutoff point to differentiate angiomyolipomas from papillary and chromophobe RCCs, the sensitivity and specificity were 90.0% and 96.4%, respectively. CONCLUSION Quantitative analysis of CEUS can show quantification of enhancement features of different renal tumor histotypes and may be helpful in their differential diagnosis.

Differentiation of subtypes of renal cell carcinoma with contrast-enhanced ultrasonography

We aimed to assess the difference of enhancement patterns among the three RCC subtypes with contrast-enhanced ultrasound (CEUS). Two hundreds cases of pathologically proved clear cell renal cell carcinomas (ccRCC), 58 papillary renal cell carcinomas (pRCC) and 51 chromophobe renal cell carcinomas (chRCC) underwent preoperative conventional ultrasound and CEUS. The wash-in and wash-out pattern, peak enhancement degree and homogeneity, and the presence of pseudocapsule were evaluated by two blinded observers respectively. The interreader agreement in the characterization of CEUS features between two observers was good (κ  = 0.649-0.775). Compared with pRCCs and chRCCs, ccRCCs demonstrated higher frequency of simultaneous wash-in pattern, hyperenhancement and heterogeneity with necrotic areas. Most pRCCs and chRCCs manifested hypoenhancement, homogeneity, fast wash-out and presence of pseudocapsule. The only difference we obtained between pRCC and chRCC was the wash-in pattern, with slow wash-in in pRCC and simultaneous wash-in in chRCC. In small lesions with long diameter≤3 cm, the majority of the three subtypes of RCC showed homogeneous enhancement and there was no difference among them. CEUS was a useful method to preoperatively differentiate the ccRCC from non-ccRCC subtypes. There were no distinguishing features identifid on CEUS that allowed reliable differentiation of pRCC from chRCC.

Qualitative and Quantitative Analysis with Contrast-Enhanced Ultrasonography: Diagnosis Value in Hypoechoic Renal Angiomyolipoma

Objective To evaluate the value of enhancement features and quantitative parameters of contrast-enhanced ultrasonography (CEUS) in differentiating solid hypoechoic renal angiomyolipomas (AMLs) from clear cell renal cell carcinomas (ccRCCs). Materials and Methods We analyzed the enhancement features and quantitative parameters of CEUS in 174 hypoechoic renal masses (32 AMLs and 142 ccRCCs) included in the study. Results Centripetal enhancement pattern was more common in AMLs than in ccRCCs on CEUS (71.9% vs. 23.2%, p < 0.001). At peak enhancement, all AMLs showed homogeneous enhancement (100% in AML, 27.5% in ccRCCs; p < 0.001). Quantitative analysis showed no significant difference between rise time and time to peak. Tumor-to-cortex (TOC) enhancement ratio in AMLs was significantly lower than that in ccRCCs (p < 0.001). The criteria of centripetal enhancement and homogeneous peak enhancement together with TOC ratio < 91.0% used to differentiate hypoechoic AMLs from ccRCCs resulted in a sensitivity and specificity of 68.9% and 95.8%, respectively. Conclusion Both qualitative and quantitative analysis with CEUS are valuable in the differential diagnosis of hypoechoic renal AMLs from ccRCCs.

Virtual Touch quantification using acoustic radiation force impulse (ARFI) technology for the evaluation of focal solid renal lesions: preliminary findings

AIM To evaluate potential value of Virtual Touch quantification (VTQ) of acoustic radiation force impulse (ARFI) imaging for characterising focal solid renal lesions. MATERIALS AND METHODS Two independent operators performed 10 and five measurements of each lesion and adjacent renal cortex, respectively. Mean shear wave velocity (SWV) and shear wave velocity ratio (SWR) of histotypes were compared. RESULTS One hundred and ninety-seven renal lesions were evaluated, including 155 renal cell carcinomas (RCCs; 129 clear-cell RCCs [ccRCCs], 14 papillary RCCs [pRCCs], and 12 chromophobe RCCs [cRCCs]) and 42 angiomyolipomas (AMLs). The interoperator reproducibility of SWV of renal tumours and renal cortex were good (ICC=0.852, and 0.903, respectively). SWV of the renal cortex at a depth of <4 cm was significant higher than that at a depth of >4 cm. Regardless of the subtypes of RCC, SWV and SWR of RCCs differed significantly from those of AMLs (2.28±0.85 versus 1.98±0.85; 1.09±0.56 versus 0.78±0.34; p=0.045 and p<0.001, respectively). At cut-off points of SWV >1.87 m/s or SWR >0.84 to differentiate RCCs from AMLs, the sensitivity and specificity were 47.5%, 33.2% or 47.5%, 30.2%, respectively. When the subtypes of RCCs were taken into account, SWV and SWR of ccRCCs were significantly higher than those of pRCCs, cRCCs, and AMLs, while there was no significant difference among the latter. With SWV >1.98 m/s or SWR >0.80 as the cut-off point to differentiate ccRCCs from other renal tumours, the sensitivity and specificity were 69.8%, 65% or 76.8%, 73.4%, respectively. CONCLUSION The ARFI technique offers additional information regarding renal tumour elasticity with good reproducibility. SWV and SWR are potential biomarkers in this setting, helping to differentiate ccRCC from other renal tumour histotypes.

Contrast-enhanced ultrasound characterization of renal mucinous tubular and spindle cell carcinoma: report of two cases.

Mucinous tubular and spindle cell carcinoma of the kidney is a relatively rare pathologic entity that has recently been described in the World Health Organization 2004 renal cell carcinoma classification. We report two cases of mucinous tubular and spindle cell carcinoma in which contrast‐enhanced ultrasound was used.