Treatment planning and volumetric response assessment for Yttrium-90 radioembolization: semiautomated determination of liver volume and volume of tumor necrosis in patients with hepatic malignancy.
OBJECTIVE
The primary purpose of this study was to demonstrate intraobserver/interobserver reproducibility for novel semiautomated measurements of hepatic volume used for Yttrium-90 dose calculations as well as whole-liver and necrotic-liver (hypodense/nonenhancing) tumor volume after radioembolization. The secondary aim was to provide initial comparisons of tumor volumetric measurements with linear measurements, as defined by Response Evaluation Criteria in Solid Tumors criteria, and survival outcomes.


METHODS
Between 2006 and 2009, 23 consecutive radioembolization procedures were performed for 14 cases of hepatocellular carcinoma and 9 cases of hepatic metastases. Baseline and follow-up computed tomography obtained 1 month after treatment were retrospectively analyzed. Three observers measured liver, whole-tumor, and tumor-necrosis volumes twice using semiautomated software.


RESULTS
Good intraobserver/interobserver reproducibility was demonstrated (intraclass correlation [ICC] > 0.9) for tumor and liver volumes. Semiautomated measurements of liver volumes were statistically similar to those obtained with manual tracing (ICC = 0.868), but they required significantly less time to perform (p < 0.0001, ICC = 0.088). There was a positive association between change in linear tumor measurements and whole-tumor volume (p < 0.0001). However, linear measurements did not correlate with volume of necrosis (p > 0.05). Dose, change in tumor diameters, tumor volume, and necrotic volume did not correlate with survival (p > 0.05 in all instances). However, Kaplan-Meier curves suggest that a >10% increase in necrotic volume correlated with survival (p = 0.0472).


CONCLUSIONS
Semiautomated volumetric analysis of liver, whole-tumor, and tumor-necrosis volume can be performed with good intraobserver/interobserver reproducibility. In this small retrospective study, measurements of tumor necrosis were suggested to correlate with survival.
Monsky
Wayne L
WL
Department of Radiology, University of California Davis Medical Center, Sacramento, CA 95817, USA. wayne.monsky@ucdmc.ucdavis.edu
Garza
Armando S
AS
Kim
Isaac
I
Loh
Shaun
S
Lin
Tzu-Chun
TC
Li
Chin-Shang
CS
Fisher
Jerron
J
Sandhu
Parmbir
P
Sidhar
Vishal
V
Chaudhari
Abhijit J
AJ
Lin
Frank
F
Deutsch
Larry-Stuart
LS
Badawi
Ramsey D
RD
D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000628:therapy*; D015331:Cohort Studies; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D015588:Observer Variation; D009929:Organ Size; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes