Lack of Anatomical Concordance between Preablation and Postablation CT Images:A Risk Factor Related to Ablation Site Recurrence

Objective. Variation in the position of the liver between preablation and postablation CT images hampers assessment of treatment of colorectal liver metastasis (CRLM). The aim of this study was to test the hypothesis that discordant preablation and postablation imaging is associated with more ablation site recurrences (ASRs). Methods. Patients with CRLM were included. Index-tumor size, location, number, RFA approachs and ablative margins were obtained on CT scans. Preablation and postablation CT images were assigned a “Similarity of Positioning Score” (SiPS). A suitable cutoff was determined. Images were classified as identical (SiPS-id) or nonidentical (SiPS-diff). ASR was identified prospectively on follow-up imaging. Results. Forty-seven patients with 97 tumors underwent 64 RFA procedures (39 patients/63 tumors open RFA, 25 patients/34 tumours CT-targeted RFA, 12 patients underwent >1 RFA). Images of 52 (54%) ablation sites were classified as SiPS-id, 45 (46%) as SiPS-diff. Index-tumor size, tumor location and number, concomitant partial hepatectomy, and RFA approach did not influence the SiPS. ASR developed in 11/47 (23%) patients and 20/97 (21%) tumours. ASR occurred less frequently after open RFA than after CT targeted RFA (P20 mm and CT-targeted RFA as independent risk factors for ASR. Conclusion. Variation in anatomical concordance between preablation and postablation images, index-tumor size, and a CT-targeted approach are risk factors for ASR in CRLM

Diffusion weighted imaging in the liver

Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an apparent diffusion coefficient (ADC), which reflects the diffusion properties unique to each type of tissue. DWI has been originally used in neuroradiology. More recently, DWI has increasingly been used in addition to conventional unenhanced and enhanced magnetic resonance imaging (MRI) in other parts of the body. The reason for this delay was a number of technical problems inherent to the technique, making DWI very sensitive to artifacts, which had to be overcome. With assessment of ADC values, DWI proved to be helpful in characterization of focal liver lesions. However, DWI should always be used in conjunction to conventional MRI since there is considerable overlap between ADC values of benign and malignant lesions. DWI is useful in the detection of hepatocellular carcinoma in the cirrhotic liver and detection of liver metastases in oncological patients. In addition, DWI is a promising tool in the prediction of tumor responsiveness to chemotherapy and the follow-up of oncological patients after treatment, as DWI may be capable of detecting recurrent disease earlier than conventional imaging. This review focuses on the most common applications of DWI in the liver

Increase in Volume of Ablation Zones during Follow-up Is Highly Suggestive of Ablation Site Recurrence in Colorectal Liver Metastases Treated with Radiofrequency Ablation

Purpose: To test the hypothesis that volume changes of ablation zones (AZs) on successive computed tomography (CT) scans could predict ablation site recurrences (ASRs) in patients with colorectal liver metastases treated by radiofrequency (RF) ablation. Materials and Methods: RF ablation was performed in 58 patients with 117 metastases. Metastasis volumes and AZ volumes were measured before RF ablation, 1 week after RF ablation (t1), and every 3 months in the first year after RF ablation (t2-t5). Volumetry was performed semiautomatically on CT scans by drawing freehand regions of interest in the portal venous phase on 2-mm-thickness slices. ASR was defined as contrast enhancement on follow-up imaging or by a hot spot on fludeoxyglucose F 18 positron emission tomography combined with computed tomography (FDG-PET/CT) scanning. Proportional volume change of an AZ was defined as the difference in volume percentages between two successive time points of measurement. Negative values represented a volume decrease, and positive values represented a volume increase. Intraobserver variability and interobserver variability were evaluated by using intraclass correlation coefficients (ICCs). Results: ASRs occurred in 15 patients with 27 AZs. An increase in volume occurred in 26 AZs (96%) with ASRs. AZs without ASR showed no volume increase. Although proportional volume changes at t1-t2 were not predictive for ASR, subsequent volume changes were predictive for ASR. Contrast-enhanced CT-based evaluation detected ASRs in 17 (63%) of 27 AZs, 7 (26%) of 27 AZs were negative, and there was doubt in 3 (11%) of 27 AZs. Intraobserver variability and interobserver variability were good (0.998 [95% confidence interval [CI] 0.996-0.999; P <.001] and 0.993 [95% CI 0.987-0.996; P <.001]). Conclusions: Volumetry of AZs is useful because a volume increase of an AZ during follow-up is highly suggestive of ASR. Negative volume changes of the AZ from t1-t2 were not correlated with the development of ASRs, but subsequent volume changes. were predictive for ASRs

The impact of hepatic steatosis on liver regeneration after partial hepatectomy

<p>Background & Aim Experimental studies in animals have suggested that liver regeneration is impaired in steatotic livers. However, few studies have focused on the impact of steatosis in patients undergoing partial hepatectomy (PH). This study aims to determine the role of steatosis on liver regeneration in humans following PH. Methods Eighty-eight patients undergoing PH were included in this study. All patients underwent CT-scanning of the liver preoperatively and 7days after surgery. Additional CT-scans were performed 6months post-operatively. Preoperative and post-operative volumes of the total liver (TLV), future liver remnant (FLR) and liver remnant (LR) were measured on CT-scans. Regeneration indices (RI) were calculated at 7days and 6months using the formula: (Volume LRVolume FLR)/Volume FLRx100%. Based on histological examination of the resected part of the liver, patients were classified into three groups: (1) no steatosis, (2) mild steatosis (129%) and (3) moderate-to-severe steatosis (30%). Results The early RI (at day 7) was 40%, 24% and 20% for patients in group 1, 2 and 3 respectively. Late RI (at 6months) was 81% for group 1, 44% for group 2 and 22% for group 3 (P=0.019). At 7days, the LR represented 79%, 80% and 79% of the TLV for groups 13. At 6months, this was 93%, 92% and 79% respectively. Conclusion Although early RI after PH did not differ in patients with or without steatosis, the late RI in patients with moderate-to-severe steatosis was lower, suggesting that late liver regeneration is impaired in these patients.</p>

Influence of Preoperative Chemotherapy on CT Volumetric Liver Regeneration Following Right Hemihepatectomy

An increasing number of patients undergo major liver resection following preoperative chemotherapy. Liver regeneration may be impaired in these patients, predisposing them to postoperative liver dysfunction. The aim of the present study was to evaluate the effects of preoperative chemotherapy on liver regeneration after partial liver resection. Patients planned to receive right hepatectomy either with (group B) or without (group A) prior chemotherapy were identified retrospectively from a prospective multi-institutional database created in the conduct of a national randomized controlled trial (RCT). Prior chemotherapy was neither an inclusion nor an exclusion criterion of the trial. Future remnant liver volume (FRLV) was calculated by measuring total functional liver volume and resection specimen on preoperative computed tomography (CT) scans. Remnant liver volume after 7 days (V (RLV7days)) was measured on scheduled postoperative CT scans. The early regeneration index 7 days after surgery (RI (early)) was calculated as [(V (RLV7days) - FRLV) / FRLV] x 100 %. Data are expressed as median (interquartile range). A total of 72 patients were enrolled: 45 in group A and 27 in group B. For the whole group, the liver remnant showed a 58 % (39 %) increase in volume at day 7 (1) day. The RI (early) was not significantly different between groups A and B, 60 % (36 %) and 50 % (43 %), respectively (p = 0.47). The RI (early) was significantly lower in patients who had undergone more than six cycles of chemotherapy. Preoperative chemotherapy does not seem to have a negative impact on early liver regeneration after partial liver resectio