Radiofrequency ablation of hepatocellular carcinoma guided by real-time physics-based ablation simulation: a prospective study.

OBJECTIVES: To assess the safety and efficacy of radiofrequency ablation (RFA) guidance software that incorporated patient-specific physics-based simulation of each ablation volume. MATERIALS AND METHODS: Patients referred for curative ablation of hepatocellular carcinoma (HCC) of 2-5 cm diameter were prospectively enrolled. RFA was performed under general anesthesia. Procedure planning and intraprocedural modifications were guided by computer simulation of each ablation. The segmented target (tumor with 5 mm margin) was registered to and superimposed on subsequent 3D multiplanar images. The applied RF energy was used to calculate a simulated ablation volume which was displayed relative to the electrode and segmented target, to depict any untreated target tissue. After each additional ablation, the software updated the accumulated simulated ablation volume in relation to the target. The primary endpoints were technical efficacy and rate of local tumor progression (LTP). RESULTS: Sixty-eight tumors were ablated during 57 procedures in 52 patients (68.3 ± 9.2 years old, 78.8% male); 15 (26.3%) had multiple lesions and 23 (39.1%) had prior HCC treatment. The mean tumor diameter was 2.73 (±0.64) cm. The intraprocedural simulation directed additional overlapping ablations in 75.9% of tumors. Technical success and efficacy were 100% at 3-month contrast enhanced CT or MRI follow-up after the single treatment session. Cumulative incidence function estimates for 1- and 2-year LTP were 3.9% and 20.2%, respectively. CONCLUSION: This prospective study found computer-assisted guidance that simulated each ablation was both safe and efficacious. The low rate of LTP was similar to studies that employed stereotactic guidance and ablation confirmation, without requiring a second contrast enhanced study.

Cholecystokinin to Enhance the Safety of Ablation of Liver Tumors Adjacent to the Gallbladder.

This retrospective case review describes the potential for intravenous cholecystokinin (CCK) to improve the safety margin between the hepatic tumor and gallbladder (GB) for hepatic tumor ablation. Eight patients with primary hepatic neoplasms adjacent to the GB underwent CCK administration before ablation. GB volume and contact area measurements were performed before and after CCK administration to assess the degree of contraction. The planned ablation was successful in 7 patients (88%) after CCK administration, although 5 patients (63%) also had hydrodissection. After CCK, the median GB volume reduction was 22%, and tumor contact area with the GB was reduced by 20%. There was no evidence for CCK-related adverse events. CCK administration before ablation of hepatic neoplasms abutting the GB is a safe and simple method that may be an adjunct to needle decompression or hydrodissection of the GB.

Gunther Tulip Filter Strut Penetration: Benign Long-Term Follow-up.

PURPOSE: To describe the natural history of Gunther Tulip filter (GTF) strut penetration based on the computed tomography (CT)-documented distance penetrated over time and any clinical manifestations. MATERIALS AND METHODS: The records of 203 patients (mean age, 59.1 years; 59.4% men) who had had an infrarenal GTF placed for venous thromboembolism (84.2%) with contraindications to anticoagulation (95.1%) and had CT follow-up were reviewed retrospectively for clinical or imaging evidence of complications. Filter strut penetration was measured on axial images from the outer caval wall to the inner edge of the distal end of each strut. Filter strut behavior over time was modeled using a linear mixed model. RESULTS: The extent of penetration correlated positively with filter dwell time (P < .001) but plateaued at 3.3 mm at 10-year follow-up. At median 4.7-year follow-up 79.3% of patients had at least 1 strut that was >0.2 mm and 31% had a strut >3 mm from the inferior vena caval wall. The extent of strut penetration was greater at all time points for women (P = .002). Abutment or entry into an adjacent structure was identified in 183 struts of 105 (52.7%) filters; of the 80 filters with CT follow-up, 47% showed progression and 19% regressed. There were no symptoms referable to filter strut penetration. CONCLUSIONS: GTF struts often penetrate the inferior vena cava progressively; however, this tends to plateau by 10 years. The limited long-term progression and a very low incidence of symptomatic complications together support a noninterventional approach to the finding of an asymptomatic GTF strut penetration.

CT characterization of retractor related liver injuries after pancreaticoduodenectomy: Retrospective analysis of a single institution experience.

PURPOSE: Retractor related liver injuries (RRLI) are reported after upper gastrointestinal tract surgeries; most commonly laparoscopic cholecystectomy and gastric surgeries. The aim of this study was to characterize the incidence, identification, type, severity, clinical features and risk factors for RRLI after open and robotic pancreaticoduodenectomy. METHODS: A 6-year retrospective study of 230 patients was performed. Clinical data was extracted from the electronic medical record. Post-operative imaging was reviewed and graded using the American Association for the Surgery of Trauma (AAST) liver injury scale. RESULTS: 109 patients met eligibility criteria. RRLI occurred in 23/109 (21.1%), with a higher incidence in the robotic/combinedapproach (4/9) compared with open (19/100). Most common injury was an intraparenchymal hematoma (56.5%), grade II (78.3%), located in segments II/III (77%). 39.1% of injuries were not reported on the CT interpretation. There was a statistically significant elevation of postoperative AST/ALT in the RRLI group [median AST 219.5 vs. 72.0 (p < 0.001), ALT 203.0 vs. 69.0 (p < 0.001)]. Trends toward lower preoperative platelet counts and longer operations were observed in the RRLI group. No significant difference in hospital length of stay or post-operative pain scores were noted. CONCLUSION: RRLI occurred frequently after pancreaticoduodenectomy, however most injuries were low grade and the only clinical significance was a transient increase in transaminases. A trend toward higher injury rates was observed in robotic cases. In this population, RRLI was often unrecognized on postoperative imaging.

Validation of Software for Patient-Specific Real-Time Simulation of Hepatic Radiofrequency Ablation.

RATIONALE AND OBJECTIVES: CT-guided radiofrequency ablation (RFA) is a potentially curative minimally invasive treatment for liver cancer. Local tumor recurrence limits the success of RFA for large or irregular tumors as it is difficult to visualize the tissue destroyed. This study was designed to validate a real-time software-simulated ablation volume for intraprocedural guidance. MATERIALS AND METHODS: Software that simulated RFA physics calculated ablation volumes in 17 agar-albumin phantoms (7 with a simulated vessel) and in six in-vivo (porcine) ablations. The software-modeled volumes were compared with the actual ablations (physical lesion in agar, contrast CT in the porcine model) and to the volume predicted by the manufacturer's charts. Error was defined as the distance from evenly distributed points on the segmented true ablation volume surfaces to the closest points on the corresponding computer-generated model, and for the porcine model, to the manufacturer-specified ablation volume. RESULTS: The average maximum error of the simulation was 2.8 mm (range to 4.9 mm) in the phantoms. The heat-sink effect from the simulated vessel was well-modeled by the simulation. In the porcine model, the average maximum error of the simulation was 5.2 mm (range to 8.1 mm) vs 7.8 mm (range to 10.0mm) for the manufacturer's model (p = 0.009). CONCLUSION: A real-time computer-generated RFA model incorporated tine position, energy deposited, and large vessel proximity to predict the ablation volume in agar phantoms with less than 3mm maximum error. Although the in-vivo model had slightly higher maximum error, the software better predicted the achieved ablation volume compared to the manufacturer's ablation maps.

Activation of stem cell up-regulation/mobilization: a cardiovascular risk in both mice and humans with implications for liver disease, psoriasis and SLE.

Experimentally induced injury triggers up-regulation and mobilization of stem cells in Apoe -/- mice that causes accelerated atherosclerosis. Abca1 -/- Abcg1-/- mice have chronic activation of stem cell up-regulation/mobilization and accelerated atherosclerosis. In addition, the Abca1 -/- Abcg1-/- mice have elevation of serum cytokines G-CSF, IL-17 and IL-23, each necessary for stem cell mobilization. IL-17 and IL-23 are elevated in two human illnesses that have cardiovascular (CV) risk independent of traditional risk factors-SLE and psoriasis. Serum G-CSF, which can be elevated in liver disease, predicts major adverse cardiovascular events in humans. These serum cytokine elevations suggest activation of the stem cell mobilization mechanism in humans that results, as in mice, in accelerated atherosclerosis. Efforts to reduce CV disease in these patient populations should include mitigation of the diseases that trigger stem cell mobilization. Since activation of the stem cell up-regulation/mobilization mechanism appears to accelerate human atherosclerosis, use of stem cells as therapy for arterial occlusive disease should distinguish between direct administration of stem cells and activation of the stem cell up-regulation/mobilization mechanism.

Liver Abscesses: Factors That Influence Outcome of Percutaneous Drainage.

OBJECTIVE: The purpose of this study was to identify the details of percutaneous catheter drainage (PCD) of pyogenic liver abscesses, the etiologic factors, and the management techniques that contribute to successful treatment. MATERIALS AND METHODS: The records of 75 consecutively registered patients who underwent PCD of 96 abscesses at a single institution between May 2009 and May 2014 were retrospectively reviewed. Thirty-nine patients (52%) were oncology patients, and 36 (48%) had recently undergone abdominal surgery. Primary success was defined as abscess healing with the primary PCD intervention and 30-day postdrainage survival. Salvage success was defined as abscess healing with follow-up secondary PCD placement for symptomatic hepatic satellite collections or for clinical recurrence. Catheter adjustments were performed during follow-up to optimize existing drains. Univariate, multivariate, and general linear mixed model analyses were performed. The median follow-up time after catheter removal was 6 months (range, 2-62 months). RESULTS: Drains were primarily successful in 54 patients (72%), and 17 patients (23%) needed salvage PCD; thus, overall success was achieved in 71 patients (95%). The other four patients (5%) died of sepsis. The primary success rate was reduced in patients with unresectable malignancies (p = 0.01), multiple abscesses (p = 0.01), and output ≥ 15 mL/d at catheter endpoint (n = 7, p = 0.001). Only unresectable malignancies had slightly lower overall success. Large abscesses (> 150 cm3) required more catheter adjustments and longer drainage duration to reach abscess cavity closure. Successfully drained abscesses reached cavity closure a mean of 23 days (95% CI, 20-27 days) after treatment. CONCLUSION: PCD was effective first-line treatment of complicated pyogenic liver abscesses, which often require catheter adjustment and salvage drainage procedures to reliably achieve success.

Hypersplenism in liver disease and SLE revisited: current evidence supports an active rather than passive process.

BACKGROUND: Active and passive theories have been advanced to explain splenomegaly and cytopenias in liver disease. Dameshek proposed active downregulation of hematopoiesis. Doan proposed passive trapping of blood components in a spleen enlarged by portal hypertension. Recent findings do not support a passive process. DISCUSSION: Cytopenias and splenomegaly in both liver disease and systemic lupus erythematosus (SLE) poorly correlate with portal hypertension, and likely reflect an active process allocating stem cell resources in response to injury. Organ injury is repaired partly by bone-marrow-derived stem cells. Signaling would thus be needed to allocate resources between repair and routine marrow activities, hematologic and bone production. Granulocyte-colony stimulating factor (G-CSF) may play a central role: mobilizing stem cells, increasing spleen size and downregulating bone production. Serum G-CSF rises with liver injury, and is elevated in chronic liver disease and SLE. Signaling, not sequestration, likely accounts for splenomegaly and osteopenia in liver disease and SLE. The downregulation of a non-repair use of stem cells, bone production, suggests that repair efforts are prioritized. Other non-repair uses might be downregulated, namely hematologic production, as Dameshek proposed. SUMMARY: Recognition that an active process may exist to allocate stem-cell resources would provide new approaches to diagnosis and treatment of cytopenias in liver disease, SLE and potentially other illnesses.