Multimodality imaging assessment of the deleterious role of the intraluminal thrombus on the growth of abdominal aortic aneurysm in a rat model.

OBJECTIVES: To evaluate imaging changes occurring in a rat model of elastase-induced abdominal aortic aneurysm (AAA), with emphasis on the intraluminal thrombus (ILT) occurrence. METHODS: The post-induction growth of the AAA diameter was characterized using ultrasound in 22 rats. ILT was reported on 13 rats that underwent 14 magnetic resonance imaging (MRI) 2-18 days post-surgery, and on 10 rats that underwent 18 fluoro-deoxyglucose (FDG) positron emission tomography (PET)/microcomputed tomography examinations 2-27 days post-surgery. Logistic regressions were used to establish the evolution with time of AAA length, diameter, ILT thickness, volume, stratification, MRI and FDG PET signalling properties, and histological assessment of inflammatory infiltrates. RESULTS: All of the following significantly increased with time post-induction (p < 0.001): AAA length, AAA diameter, ILT maximal thickness, ILT volume, ILT iron content and related MRI signalling changes, quantitative uptake on FDG PET, and the magnitude of inflammatory infiltrates on histology. However, the aneurysm growth peak followed occurrence of ILT approximately 6 days after elastase infusion. CONCLUSION: Our model emphasizes that occurrence of ILT precedes AAA peak growth. Aneurysm growth is associated with increasing levels of iron, signalling properties changes in both MRI and FDG PET, relating to its biological activities. KEY POINTS: • ILT occurrence in AAA is associated with increasing FDG uptake and growth. • MRI signalling changes in ILT reflect activities such as haemorrhage and RBC trapping. • Monitoring ILT activities using MRI may require no exogenous contrast agent.

Prospective comparison of freehand and electromagnetic needle tracking for US-guided percutaneous liver biopsy.

PURPOSE: To prospectively compare electromagnetic needle tracking (EMT) and freehand ultrasound (US)-guided liver biopsies. MATERIALS AND METHODS: Among 60 consecutive US-guided liver biopsies performed by staff radiologists (senior operators) and residents (junior operators), 30 were performed freehand and 30 with EMT. Needle placement time, numbers of needle punctures and pullbacks, and subjective scores of procedure difficulty were compared by χ(2) or Student t test. RESULTS: Diagnostic success rates, defined by the procurement of an adequate histopathologic specimen, were 96.6% for freehand biopsy and 100% with EMT. Needle placement time was significantly lower for EMT (mean ± standard deviation, 45.8 s ± 48.1) than for freehand procedures (143.2 s ± 122.1; P < .01). In the freehand group, needle placement times were 179.6 seconds ± 133.3 for junior operators and 106.8 seconds ± 101.3 for senior operators (P = .15). In the EMT group, needle placement times were 49.2 seconds ± 55 for junior operators and 42.5 seconds ± 41.2 for senior operators (P = .53). The number of needle pullbacks was significantly lower for senior operators (1.2 ± 0.80) compared with junior operators (2.4 ± 1.4) in the freehand group (P = .01), with no significant difference (junior, 0.47 ± 0.92; senior, 0.67 ± 0.72; P = .24) in the EMT group. The postprocedural difficulty score was lower in the EMT group (1.5 ± 0.7) than in the freehand group (2.1 ± 1.1; P = .02). Needle placement time and number of needle pullbacks were lower in the EMT group, even after taking into account tumor size and depth and operator experience. CONCLUSIONS: The EMT procedure shortens needle placement time and reduces the number of needle pullbacks needed for redirection, regardless of operator experience.

Long Term Efficacy and Assessment of Tumor Response of Transarterial Chemoembolization in Neuroendocrine Liver Metastases: A 15-Year Monocentric Experience.

BACKGROUND: transarterial chemoembolization (TACE) is an established treatment for neuroendocrine tumor (NET) liver metastases. The aim was to evaluate the long-term treatment efficacy of TACE for NET liver metastases, and correlate imaging response with survival. METHODS: this IRB-approved, single-center, retrospective study evaluated all TACE procedures performed for NET liver metastases from 2003-2017 for imaging tumor response (RECIST and mRECIST), time to liver progression (TTLP), time to untreatable progression with TACE (TTUP), and overall survival (OS). Patient, tumor, and treatment characteristics were analyzed as prognostic factors. Survival curves according to the Kaplan-Meier method were compared by Log-rank test. Tumor responses according to RECIST and mRECIST were correlated with OS. RESULTS: 555 TACE procedures were performed in 202 NET patients (38% grade 1, 60% grade 2) with primary tumors originating from pancreas, small bowel, and lung (39, 26, and 22% respectively). Median follow-up was 8.2 years (90-139 months). Median TTLP and TTUP were 19.3 months (95%CI 16.3-22.3) and 26.2 months (95%CI 22.3-33.1), respectively. Median OS was 5.3 years (95%CI 4.2-6.7), and was higher among mRECIST responders (80.5 months; 95%CI 64.6-89.8) than in non-responders (39.6 months; 95%CI = 32.8-60.2; p < 0.001). In multivariable analysis, age, tumor grade and liver involvement predicted worse OS, whereas administration of somatostatin analogs correlated with improved OS. CONCLUSION: TACE for NET liver metastases provides objective response and sustained local disease control rates. RECIST and mRECIST responses correlate with OS.

Percutaneous bone biopsies: comparison between flat-panel cone-beam CT and CT-scan guidance.

PURPOSE: This study was designed to compare the accuracy of targeting and the radiation dose of bone biopsies performed either under fluoroscopic guidance using a cone-beam CT with real-time 3D image fusion software (FP-CBCT-guidance) or under conventional computed tomography guidance (CT-guidance). METHODS: Sixty-eight consecutive patients with a bone lesion were prospectively included. The bone biopsies were scheduled under FP-CBCT-guidance or under CT-guidance according to operating room availability. Thirty-four patients underwent a bone biopsy under FP-CBCT and 34 under CT-guidance. We prospectively compared the two guidance modalities for their technical success, accuracy, puncture time, and pathological success rate. Patient and physician radiation doses also were compared. RESULTS: All biopsies were technically successful, with both guidance modalities. Accuracy was significantly better using FP-CBCT-guidance (3 and 5 mm respectively: p = 0.003). There was no significant difference in puncture time (32 and 31 min respectively, p = 0.51) nor in pathological results (88 and 88 % of pathological success respectively, p = 1). Patient radiation doses were significantly lower with FP-CBCT (45 vs. 136 mSv, p < 0.0001). The percentage of operators who received a dose higher than 0.001 mSv (dosimeter detection dose threshold) was lower with FP-CBCT than CT-guidance (27 vs. 59 %, p = 0.01). CONCLUSIONS: FP-CBCT-guidance for bone biopsy is accurate and reduces patient and operator radiation doses compared with CT-guidance.

Predisposing factors of liver necrosis after transcatheter arterial chemoembolization in liver metastases from neuroendocrine tumor.

PURPOSE: To investigate predictive factors for liver necrosis after transcatheter arterial chemoembolization (TACE) of neuroendocrine liver metastases. METHODS: A total of 164 patients receiving 374 TACE were reviewed retrospectively to analyze predictive factors of liver necrosis. We analyzed patient age and sex; metastasis number and location; percentage of liver involvement; baseline liver function test; and pretreatment imaging abnormalities such as bile duct dilatation (BDD), portal vein narrowing (PVN), and portal vein thrombosis (PVT). We analyzed TACE technique such as Lipiodol or drug-eluting beads (DEB) as the drug's vector; dose of chemotherapy; diameter of DEB; and number, frequency, and selectivity of TACE. RESULTS: Liver necrosis developed after 23 (6.1 %) of 374 TACE. In multivariate analysis, DEB > 300 µm in size induced more liver necrosis compared to Lipiodol (odds ratio [OR] 35.20; p < 0.0001) or with DEB < 300 µm in size (OR 19.95; p < 0.010). Pretreatment BDD (OR 119.64; p < 0.0001) and PVT (OR 9.83; p = 0.030) were predictive of liver necrosis. BDD or PVT responsible for liver necrosis were present before TACE in 59 % (13 of 22) and were induced by a previous TACE in 41 % (9 of 22) of cases. CONCLUSION: DEB > 300 µm in size, BDD, and PVT are responsible for increased rate of liver necrosis after TACE. Careful analysis of BDD or PVT on pretreatment images as well as images taken between two courses can help avoid TACE complications.

Ruptured subscapular artery aneurysm and subclavian artery occlusion in a patient with type 1 neurofibromatosis: a case report.

INTRODUCTION: Collateral muscular artery aneurysm is exceedingly rare. We report the first case of subscapular artery aneurysm in a patient with type 1 neurofibromatosis and ipsilateral chronic subclavian artery occlusion. CASE PRESENTATION: A 74-year-old Caucasian woman with a medical history of type 1 neurofibromatosis, presented a sudden left pectoral mass, later diagnosed as a ruptured aneurysm of the left subscapular artery. It was caused by a chronic occlusion of the left subclavian artery, diagnosed on angiographies prior to embolization. CONCLUSIONS: Collateral artery aneurysm in the event of a mainstream muscular artery chronic occlusion may occur in type 1 neurofibromatosis.

Polytetrafluoroethylene-covered nitinol stent graft for treatment of carotid artery blowout syndrome in head and neck cancer patients.

OBJECTIVES/HYPOTHESIS: To evaluate the efficacy, tolerance, and outcomes of covered stents in the treatment of carotid blowout syndrome (CBS) in head and neck cancer patients. STUDY DESIGN: Individual retrospective cohort study. METHODS: We retrospectively reviewed the medical and image files of all 20 consecutive head and neck cancer patients treated with covered stent grafts for CBS. Six acute, 12 impending, and two threatened cases of CBS were treated in patients who all had previously received radiation therapy. We evaluated the feasibility, hemostatic efficacy, survival without bleeding, and complications. RESULTS: The etiologies of CBS were as follows: group 1, 13 carotid axis (common or internal carotid artery) pseudoaneurysms and one rupture; group 2, six patients with no identifiable source of bleeding on angiography but with a threatened carotid axis on computed tomography (CT). In all patients, a polytetrafluoroethylene-covered nitinol stent graft (Fluency; Bard/Angiomed GmbH & Co, Karlsruhe, Germany) was successfully placed. All of the stents were patent at the end of the procedure. Immediate hemostasis was achieved in the six hemorrhagic cases. Immediate transient ischemic attacks were observed in two patients, and carotid sinus syndrome was observed in one patient. Post-treatment bleeding was observed in five patients in group 2 and no patients in group 1. Survival without bleeding was 251 days in group 1 and 35 days in group 2. During follow-up, three asymptomatic stent thromboses occurred at a mean of 58 days. CONCLUSIONS: Covered stent placement is highly feasible and proved effective without major complications in CBS due to carotid axis bleeding.