Quantification of Enhancement of Renal Parenchymal Masses with Contrast-Enhanced Ultrasound

Abstract

The purpose of this study was to investigate the value of quantitative assessment of enhancement in diagnosing renal cell carcinoma (RCC) with contrast-enhanced ultrasound (CEUS). A total of 73 solid renal parenchymal masses underwent both conventional ultrasound and CEUS. We compared the difference in maximum diameters on conventional ultrasound and CEUS between the benign and malignant groups. Enhancement features derived from a time-intensity curve were also analyzed. The diameters of renal cancer were found to be larger on CEUS than on conventional ultrasound (p < 0.05). When cutoff values of 4.74 s for washout time and 8.52% for enhancement intensity at 60 s for diagnosing RCCs were applied, the sensitivity, specificity and area under the receiver operating characteristic curve were 67.3%, 95.2%, 86.5% and 65.4%, 81.0%, 68.4%, respectively. The sensitivity and specificity for these two enhancement characteristics combined as a criterion for differentiating RCCs from benign lesions were 44.0% and 99.1%, respectively. Early washout in the area of maximal intensity in the interior of the lesion and prolonged washout in the whole area of the lesion are specific CEUS manifestations suggestive of RCC.

Contrast-enhanced ultrasound (CEUS) of cystic and solid renal lesions: a review

“…The second criterion evaluated the lesion as a whole at 60 s post-injection; this was termed the ''washout phase,'' a time point not to be confused with qualitatively observed or quantitatively analyzed washout of contrast. The authors found that the lesion still hyperenhanced overall at this 60 s time (the ''washout phase'') relative to background renal parenchyma, with a cutoff of the whole lesion enhancing >8.52% more than background renal cortex at 60 s was specific for malignancy [62]. Of note, we have not replicated this final finding; in our subjects, we have seen delayed phase hypoenhancement (''washout'') of ccRCCs relative to normal renal parenchyma, with both qualitative (Figs.…”

Contrast enhanced ultrasound of renal masses. A reappraisal of EFSUMB recommendations and possible emerging applications.

“…Cai Y et al [45] showed that early washout in the area of maximal intensity inside of the lesion and prolonged washout in whole area of the lesion are suggestive for RCC. This behavoir seems to be the imaging expression of heterogeneous angiogenesis.…”

“…This behavoir seems to be the imaging expression of heterogeneous angiogenesis. The authors recommended to combine the hyper-enhancement in the wash-in phase with relative earlier washout of the maximal intensity area in the interior of the lesion to increase the specificity for diagnosing RCC [45].…”

Quantitative assessment of solid renal masses by contrast-enhanced ultrasound with time–intensity curves: how we do it

“…The optimal length of time to observe renal mass enhancement has not been established, but we obtain cines for at least 2 min, so that enhancement can be observed to well past nephrographic phase. From the cine, a time-intensity curve (TIC) can be created, from which quantitative perfusion parameters can be extracted [18,23,24].…”