Diagnostic ultrasound ( PDFDrive )

344 PART II Abdominal and Pelvic Sonography
A
B
C
D
FIG. 9.50 Value of Color Doppler and Microbubble-Enhanced Sonography for Determining Vascularity of a Renal Mass. (A) Sagittal
sonogram shows an isoechoic lower-pole mass and an adjacent cyst; the simultaneous power Doppler image shows low within the mass (biopsy
conirmed renal cell carcinoma). (B) Sonogram of a patient with renal failure shows a large complex cyst containing low-level echoes. The simultaneous
microbubble enhanced image shows no enhancement of the center of the mass, but it conirms enhancement of the nodular, thick wall of a cystic
renal cell carcinoma. (C) Baseline transverse sonogram of exophytic hypoechoic midpole renal mass. (D) Nephrographic phase image shows
enhancement of both normal kidney and relatively hypovascular renal cell carcinoma (arrow). (C and D courtesy of Ed Grant, MD.)
continue to increase the role of imaging-directed, particularly
ultrasound-guided, renal mass biopsy 177 (Fig. 9.51).
For patients with imaging indings (or biopsy results) deinitive
for RCC, the stage at diagnosis directly impacts prognosis. he
Robson staging classiication for RCC is the following:
I: Tumor conined within renal capsule
II: Tumor invasion of perinephric fat
III: Tumor involvement of regional lymph nodes or venous
structures
IV: Invasion of adjacent organs or distant metastases
Five-year survival rates for patients with Robson stages I, II,
III, and IV are 67%, 51%, 33.5%, and 13.5%, respectively. 178
Patients with stage I and stage II disease are treated surgically
(partial or radical nephrectomy). Patients with stage III disease,
with extensive metastatic lymphadenopathy, are oten treated
palliatively. Patients with stage III disease and tumor thrombus
are treated with radical nephrectomy and thrombectomy. Patients
with stage IV disease usually receive palliative treatment only, 179
although greater understanding of the molecular biology of RCC
has led to clinical trials of novel, small-molecule-targeted inhibitors
and monoclonal antibodies. 180
Pitfalls in Interpretation
Ultrasound is inferior to CT and MRI for staging RCC. Unfortunately,
obesity and overlying bowel gas oten make it diicult
to assess for lymphadenopathy or vascular involvement. In
thin patients and in those with minimal bowel gas, however,
the renal veins and retroperitoneum can be well assessed with
ultrasound. Sonography is excellent for assessment of the
intrahepatic IVC and for determination of the cephalad extent
of venous tumor thrombus with RCC (Fig. 9.52). Habboub
et al. 181 found the accuracy of detecting renal vein and IVC
involvement at sonography was 64% and 93%, respectively.
he addition of color Doppler sonography improved accuracy
for diagnosing both renal vein and IVC thrombus to 87%
and 100%, respectively. It is crucial to determine the location
and extent of vascular tumor thrombus to plan the surgical
approach.