The role of directional power Doppler in early detection of the onset of neoangiogenesis in a case of small hyperechoic renal lesion.

CASE REPORT: A small hyperechoic renal mass was detected in a 57 year old female. This renal mass was further characterized by the absence of peripheral or intratumoral vascularity using directional power Doppler (dpD); however, there were intralesion spots colored after Levovist (pattern 1, according to Jinzaki). By computer tomography (CT) scan, the renal mass was considered a benign lesion. Three months later, no changes were detected using ultrasonography (US), while there was evidence of a focal intra-lesion neovascular zone using dpD (pattern 1 of Jinzaki). Magnetic resonance imaging (MRI) did not display evidence for malignancy. After six months, the MRI considered the mass an angiomyolipoma (AML). However, a vascular pattern around and inside the mass (pattern 4 of Jinzaki) was evident by using US-dpD and a percutaneous renal biopsy revealed a renal cell carcinoma. CONCLUSION: This case suggests that directional power Doppler is useful for the detection of small hyperechoic renal masses considered benign by both CT scan and MRI, since dpD allows for early detection of the onset and development of neo-vascular structures. Therefore, directional power Doppler sonography would be useful in the follow up of renal masses which mimic benign lesions.

The role of directional power Doppler in vascular characterization of renal masses.

OBJECTIVES: The purpose of our study was to characterize the vascularization of frequently detected renal masses with directional power Doppler (dpD). MATERIALS AND METHODS: We analyzed 38 renal masses with B-mode sonography (US), dpD, computer tomography (CT) and/or magnetic resonance (MR) and, in some cases, also with percutaneous renal biopsy (RB). The study population included 14 renal cell carcinomas (RCC), 10 angiomyolipomas (AML), 5 other types of lesions, as complex cysts, anatomical malformations and focal pyelonephritis (PLN), 9 mass lesions classified indeterminate by imaging studies and have defied characterization by RB. The dpD evaluated the peri or intra-lesional vessels distribution according to Jinzaki vascular patterns, the presence of artero-venous fistulas (AVF) and Doppler spectrum of these lesions, especially blood-flow systolic peak velocity (SPV). RESULTS: At US, there was no statistically significant difference in lesion size, but significant difference was found in echogenicity of AML resulted all hyperechoic in respect of other types of lesions. At dpD, the vascular distribution in most of CCRs (11/14) was classified as pattern 3 or 4 (peripheral and mixed penetrating/peripheral, respectively) and was significantly different in respect to AMLs, that showed patterns 1 and 2 (intratumoral focal and penetrating, respectively), in respect to other types of lesions, that were with prevalent pattern 2, and in respect of indeterminate lesions, that presented all patterns (from 1 to 4). The SPV was more elevated in CCRs than in all other types of lesions. Three CCRs presented AVF. CONCLUSIONS: The dpD adds very important information to simple US in vascular pattern evaluation of small solid renal lesions and improve the diagnostic accuracy.

[Role of directional power-Doppler in the identification of renovascular malformations]. / Ruolo del power-Doppler direzionale nell'identificazione di malformazioni vascolari renali.

OBJECTIVE: The directional power-Doppler (dPD) is a useful tool in evaluating the renal vascularization for its high sensibility and availability. Renal vascular malformations like the arteriovenous fistulas (avF) are rare and their real incidence is unknown. We evaluated the diagnostic role of dpD in renal avF. MATERIAL AND METHODS: From January 1999 to 2002 1518 subjects (875 males, 643 females, mean age: 62 years, range: 22-87 years) have been studied by both B-mode ultrasound and by dpD. All ultrasonographies were taken with a Toshiba Power Vision 6000 by the same skilled operator. RESULTS: Among 1518 patients examined, 17 avF have been identified (diameter range: 3-18 mm) by using dPD. Four of these have an unclear etiology (congenital?) and they have been considered idiopathic. On the contrary, five are acquired: two are caused by renal biopsy, two by renal tumors and one by ureteral stent positioning, respectively. Eight patients, all affected by polycystic kidney disease, showed multiple avF. The four subjects with idiopathic avF are suffering from chronic renal failure (CRF--CrCl = 8-35 ml/min); on the contrary, among patients with polycystic kidney, five of them are on CRF (CrCl = 14-27 ml/min), three have normal renal function. The acquired avF caused by renal biopsy or by ureteral catheterization have spontaneously disappeared after 15-20 days from the causative event. CONCLUSIONS: The dPD allows to individualize the arteriovenous malformations of renal vasculature which could be underestimated or not evidenced by other instrumental methods.