Application of second generation ultrasound contrast agents in renal pseudotumors diagnostics
Article published in Urologia Polska 2008/61/Supl. 1.

authors

Andrzej Lewicki, Maciej Jędrzejczyk, Wojciech Pypno, Wiesław Jakubowski, Andrzej Kidawa, Piotr Marczyński

Oddział Urologii im. J. Kiełkiewicza, Szpital Praski w Warszawie
Zakład Diagnostyki Obrazowej, II Wydział Lekarski AM w Warszawie, Szpital Bródnowski
Klinika Urologii CMKP, Szpital im. Orłowskiego w Warszawie

summary

Introduction.

Renal pseudotumors are varieties of kidney structure which on imaging examinations can suggest neoplastic disease. The definition includes normal anatomic variants (for example hyperthrophic column of Bertin, renal hump) but also pathologic, non- neoplastic lesions like cyst, abscess or hematoma. Ultrasonography (US) gives us limited possibilities to differentiate between true and pseudo-tumor. In many cases expansive masses can not be confidently excluded and further investigations with more sophisticated methods are required.

Objectives.

Evaluation of the usefulness of contrast-enhanced ultrasonography (CEUS) in the diagnostics of renal pseudotumors. Evaluation of pseudotumors frequency occurrence among lesions directed to further investigations after grey scale US.

Materials and methods.

123 patients with 129 renal masses directed to further investigations after grey scale US were examined. The examination was performed with Voluson 730 Expert, probe C2-5 MHz. The kidneys were examined three times: grey scale with Doppler examination, Coded Pulse Inversion option (CPI; parenchymatous enhancement) after bolus injection of UCA and Coded Harmonic Angio option (CHA; vascular enhancement) after second dose of UCA. Vascularization (its regularity, modelling features) and enhancement character of the lesion and normal parenchyma were evaluated. The examination was recorded. Reference examinations were contrastenhanced computer tomography (CT) and histopathologic result of resected lesions.

Results.

Among 129 focal lesions suspected on grey scale US, 28 (21.7%) cases CEUS verified as renal pseudotumors. They were classified as follow: hyperthrophic column of Bertin 7 (25%), focal parenchyma hyperthrophy 3 (10.7%), junctional parenchyma defect 2 (7.1%), renal hump 2 (7.1%), hypoechoic renal sinus fat 1 (3.6 %), infectious lesions (scarred kidney, areas of fibrosis) 4 (14.3%), abscess 1 (3.6%), hematoma 1 (3.6 %), cystic pseudo tumors (cysts I, II according to Bosniak classification system) 5 (17.9%), pseudotumor after nephron-sparing surgery 1 (3.6 %). Differences in evaluation with CT were found in 3 lesions (10.7% of pseudtumors): CEUS: cyst cat. II; CT: solid mass; histopathologic result: cyst without malignancy; CEUS: tumor in the renal hilum; CT: area of parahiliar fatty tissue; Patient lost to for follow-up; CEUS: necrotic area (organized hematoma); CT: tumor suspected for malignancy; histopathologic result: necrosis without neoplastic cells. Compliance with histopathologic result of resected lesions (3) was: CT 33.3%, CEUS 100%. Statistical analysis: CEUS sensitivity 100%, specificity 99%, overall accuracy 99.2%, CT: sensitivity 100%, specificity 98%, overall accuracy 98.4%.

Conclusions.

1. CEUS is an efficacious method in the renal pseudotumors diagnostics. 2. Diagnostic precision of CEUS in the renal pseudotumors diagnostics is similar to CT. 3. Above 20% of lesions directed to further investigations after grey scale US in reference examinations are revealed to be pseudotumors.