Transarterial Radioembolization Ought Not to Borrow Future Liver Function from Patients with Hepatocellular Carcinoma. But Does It?

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MR Imaging–Based In Vivo Macrophage Imaging to Monitor Immune Response after Radiofrequency Ablation of the Liver

PurposeTo establish molecular magnetic resonance (MR) imaging instruments for in vivo characterization of the immune response to hepatic radiofrequency (RF) ablation using cell-specific immunoprobes.Materials and MethodsSeventy-two C57BL/6 wild-type mice underwent standardized hepatic RF ablation (70 °C for 5 minutes) to generate a coagulation area measuring 6–7 mm in diameter. CD68⁺ macrophage periablational infiltration was characterized with immunohistochemistry 24 hours, 72 hours, 7 days, and 14 days after ablation (n = 24). Twenty-one mice were subjected to a dose-escalation study with either 10, 15, 30, or 60 mg/kg of rhodamine-labeled superparamagnetic iron oxide nanoparticles (SPIONs) or 2.4, 1.2, or 0.6 mg/kg of gadolinium-160 (¹⁶⁰Gd)-labeled CD68 antibody for assessment of the optimal in vivo dose of contrast agent. MR imaging experiments included 9 mice, each receiving 10-mg/kg SPIONs to visualize phagocytes using T2¹-weighted imaging in a horizontal-bore 9.4-T MR imaging scanner, ¹⁶⁰Gd-CD68 for T1-weighted MR imaging of macrophages, or 0.1-mmol/kg intravenous gadoterate (control group). Radiological-pathological correlation included Prussian blue staining, rhodamine immunofluorescence, imaging mass cytometry, and immunohistochemistry.ResultsRF ablation–induced periablational infiltration (206.92 μm ± 12.2) of CD68⁺ macrophages peaked at 7 days after ablation (P < .01) compared with the untreated lobe. T2¹-weighted MR imaging with SPION contrast demonstrated curvilinear T2¹ signal in the transitional zone (TZ) (186 μm ± 16.9), corresponsing to Iron Prussian blue staining. T1-weighted MR imaging with ¹⁶⁰Gd-CD68 antibody showed curvilinear signal in the TZ (164 μm ± 3.6) corresponding to imaging mass cytometry.ConclusionsBoth SPION-enhanced T2¹-weighted and ¹⁶⁰Gd-enhanced T1-weighted MR imaging allow for in vivo monitoring of macrophages after RF ablation, demonstrating the feasibility of this model to investigate local immune responses.     

Radioembolization with Yttrium-90 Glass Microspheres as a First-Line Treatment for Unresectable Intrahepatic Cholangiocarcinoma—A Prospective Feasibility Study

PurposeTo evaluate the safety and effectiveness of yttrium-90 (⁹⁰Y) radioembolization as first-line treatment for unresectable intrahepatic cholangiocarcinoma (ICC).Materials and MethodsThis prospective study enrolled patients who had never received chemotherapy, liver embolization, and radiation therapy. The tumors were solitary in 16 patients, multiple in 8 patients, unilobar in 14 patients, and bilobar in 10 patients. Patients underwent transarterial radioembolization with ⁹⁰Y-labeled glass microspheres. The primary end point was hepatic progression-free survival (HPFS). Secondary end points were overall survival (OS), tumor response, and toxicity.ResultsTwenty-four patients (age, 72.3 years ± 9.3; 12 women) were included in the study. The median delivered radiation dose was 135.5 Gy (interquartile range, 77.6 Gy). The median HPFS was 5.5 months (95% CI, 3.9–7.0 months). Analysis failed to identify any prognostic factor associated with HPFS. Imaging response at 3 months showed 56% disease control, and the best radiographic response was 71% disease control. The median OS from the radioembolization treatment was 19.4 months (95% CI, 5.0–33.7). Patients with solitary ICC had significantly longer median OS than patients with multifocal ICC: 25.9 months (95% CI, 20.8–31.0 months) versus 10.7 months (95% CI, 8.0–13.4 months) (P = .02). Patients with progression on the 3-month imaging follow-up had significantly shorter median OS than patients who had stable disease at 3 months: 10.7 months (95% CI, 0.7–20.7 months) versus 37.3 months (95% CI, 16.5–58.1 months) (P = .003). Two (8%) Grade 3 toxicities were reported.ConclusionsFirst-line treatment of ICC with radioembolization showed promising OS and minimal toxicity, especially in patients with solitary tumor. Radioembolization may be considered as a first-line treatment option for unresectable ICC.     

Percutaneous MR Imaging–Guided Laser Ablation for the Treatment of Symptomatic Cervicofacial Vascular Malformations

PurposeTo evaluate the safety and effectiveness of percutaneous magnetic resonance (MR) imaging–guided laser ablation for the treatment of symptomatic soft tissue vascular malformations (VMs) in the face and neck.Materials and MethodsAn institutional review board–approved retrospective review was undertaken of all consecutive patients who underwent MR imaging–guided and monitored laser ablation for treatment of symptomatic, cervicofacial soft tissue VM. Preablation and postablation MR imaging findings were independently reviewed. Preablation and postablation VM sizes were documented. Preablation T2 signal characteristics and enhancement patterns as well as postablation change in both signal and enhancement were semiquantitatively assessed. Changes in VM size were compared using a paired t test.ResultsThirteen patients (women, 9; age, 14.5–69.5 years) with 13 VMs were treated for moderate-to-severe pain (n = 4), swelling/mass effect (n = 8), or predominantly cosmesis (n = 1) with 22 total ablation sessions. The baseline maximum VM diameter was 5.7 cm ± 4.2. At baseline, all VMs (100%) demonstrated variable T2-weighted signal hyperintensity and enhancement. For painful VM, the baseline pain score was 8 ± 1. Clinical follow-up was available for 10 patients. Of patients with available follow-up, 3 (100%) treated for moderate-to-severe pain and 7 (100%) treated for swelling/mass effect reported subjective complete or partial symptomatic relief. The patient treated predominantly for cosmetic reasons was lost to follow-up. Two patients (15.4%) experienced minor adverse events by the Society of Interventional Radiology standards. There were no major adverse events.ConclusionsMR imaging–guided and monitored percutaneous laser ablation is safe and effective for the treatment of symptomatic, cervicofacial VMs.