title: Radiofrequency ablation of liver metastases-software-assisted evaluation of the ablation zone in MDCT: tumor-free follow-up versus local recurrent disease.
abstract: The purpose of this study was to investigate differences in change of size and CT value between local recurrences and tumor-free areas after CT-guided radiofrequency ablation (RFA) of hepatic metastases during follow-up by means of dedicated software for automatic evaluation of hepatic lesions. Thirty-two patients with 54 liver metastases from breast or colorectal cancer underwent triphasic contrast-enhanced multidetector-row computed tomography (MDCT) to evaluate hepatic metastatic spread and localization before CT-guided RFA and for follow-up after intervention. Sixteen of these patients (65.1 + or - 10.3 years) with 30 metastases stayed tumor-free (group 1), while the other group (n = 16 with 24 metastases; 62.0 + or - 13.8 years) suffered from local recurrent disease (group 2). Applying an automated software tool (SyngoCT Oncology; Siemens Healthcare, Forchheim, Germany), size parameters (volume, RECIST, WHO) and attenuation were measured within the lesions before, 1 day after, and 28 days after RFA treatment. The natural logarithm (ln) of the quotient of the volume 1 day versus 28 days after RFA treament was computed: lnQ1//28/0(volume). Analogously, ln ratios of RECIST, WHO, and attenuation were computed and statistically evaluated by repeated-measures ANOVA. One lesion in group 2 was excluded from further evaluation due to automated missegmentation. Statistically significant differences between the two groups were observed with respect to initial volume, RECIST, and WHO (p < 0.05). Furthermore, ln ratios corresponding to volume, RECIST, and WHO differed significantly between the two groups. Attenuation evaluations showed no significant differences, but there was a trend toward attenuation assessment for the parameter lnQ28/0(attenuation) (p = 0.0527), showing higher values for group 1 (-0.4 + or - 0.3) compared to group 2 (-0.2 + or - 0.2). In conclusion, hepatic metastases and their zone of coagulation necrosis after RFA differed significantly between tumor-free and local-recurrent ablation zones with respect to the corresponding size parameters. A new parameter (lnQ1//28/0(volume/RECIST/WHO/attenuation)) was introduced, which appears to be of prognostic value at early follow-up CT.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany. keil@rad.rwth-aachen.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Keil
authors.forename: Philipp
authors.initials: P
authors.lastname: Bruners
authors.forename: Katharina
authors.initials: K
authors.lastname: Schiffl
authors.forename: Martin
authors.initials: M
authors.lastname: Sedlmair
authors.forename: Georg
authors.initials: G
authors.lastname: Mühlenbruch
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Marco
authors.initials: M
authors.lastname: Das
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D009367:Neoplasm Staging; D010363:Pattern Recognition, Automated; D011336:Probability; D011857:Radiographic Image Interpretation, Computer-Assisted; D015641:Radiography, Interventional / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D012984:Software; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome