Renal arteriovenous malformation treated using glue embolization under inflow and outflow control by balloon occlusion.

A 45-year-old female presented with gross hematuria. Right renal arteriovenous malformation on abdominal contrast-enhanced computed tomography necessitated urgent transcatheter arterial embolization. Right renal digital subtraction angiography revealed a single tortuous and dilated vessel converging to an aneurysmal dilated vein. To selectively embolize the malformation, we closed the arterial side with a microballoon and attempted glue embolization; filling occurred unexpectedly early, and another balloon on the vein side helped control the renal vein blood flow. Glue embolization was performed without adverse events. Glue embolization for high-flow arteriovenous malformation under balloon occlusion-mediated inflow and outflow control can effectively and safely embolize complete target vessels.

Correlation between CT Value on Lung Subtraction CT and Radioactive Count on Perfusion Lung Single Photon Emission CT in Chronic Thromboembolic Pulmonary Hypertension.

Background: Lung subtraction CT (LSCT), the subtraction of noncontrast CT from CT pulmonary angiography (CTPA) without spatial misregistration, is easily applicable by utilizing a software-based deformable image registration technique without additional hardware and permits the evaluation of lung perfusion as iodine accumulation, similar to that observed in perfusion lung single photon emission CT (PL-SPECT). The aim of this study was to use LSCT to newly assess the quantitative correlation between the CT value on LSCT and radioactive count on PL-SPECT as a reference and validate the quantification of lung perfusion by measuring the CT value in chronic thromboembolic pulmonary hypertension (CTEPH). Methods: We prospectively enrolled 47 consecutive patients with CTEPH undergoing both LSCT and PL-SPECT; we used noncontrast CT, CTPA, and LSCT to measure CT values and PL-SPECT to measure radioactive counts in areas representing three different perfusion classes­no perfusion defect, subsegmental perfusion defect, and segmental perfusion defect; we compared CT values on noncontrast CT, CTPA, and LSCT and radioactive counts on PL-SPECT among the three classes, then assessed the correlation between them. Results: Both the CT values and radioactive counts differed significantly among the three classes (p < 0.01 for all) and showed weak correlation (ρ = 0.38) by noncontrast CT, moderate correlation (ρ = 0.61) by CTPA, and strong correlation (ρ = 0.76) by LSCT. Conclusions: The CT value measurement on LSCT is a novel quantitative approach to assess lung perfusion in CTEPH and only correlates strongly with radioactive count measurement on PL-SPECT.

Image quality and radiologists' subjective acceptance using model-based iterative and deep learning reconstructions as adjuncts to ultrahigh-resolution CT in low-dose contrast-enhanced abdominopelvic CT: phantom and clinical pilot studies.

PURPOSE: In contrast-enhanced abdominopelvic CT (CE-APCT) for oncologic follow-up, ultrahigh-resolution CT (UHRCT) may improve depiction of fine lesions and low-dose scans are desirable for minimizing the potential adverse effects by ionizing radiation. We compared image quality and radiologists' acceptance of model-based iterative (MBIR) and deep learning (DLR) reconstructions of low-dose CE-APCT by UHRCT. METHODS: Using our high-resolution (matrix size: 1024) and low-dose (tube voltage 100 kV; noise index: 20-40 HU) protocol, we scanned phantoms to compare the modulation transfer function and noise power spectrum between MBIR and DLR and assessed findings in 36 consecutive patients who underwent CE-APCT (noise index: 35 HU; mean CTDIvol: 4.2 ± 1.6 mGy) by UHRCT. We used paired t-test to compare objective noise and contrast-to-noise ratio (CNR) and Wilcoxon signed-rank test to compare radiologists' subjective acceptance regarding noise, image texture and appearance, and diagnostic confidence between MBIR and DLR using our routine protocol (matrix size: 512; tube voltage: 120 kV; noise index: 15 HU) for reference. RESULTS: Phantom studies demonstrated higher spatial resolution and lower low-frequency noise by DLR than MBIR at equal doses. Clinical studies indicated significantly worse objective noise, CNR, and subjective noise by DLR than MBIR, but other subjective characteristics were better (P < 0.001 for all). Compared with the routine protocol, subjective noise was similar or better by DLR, and other subjective characteristics were similar or worse by MBIR. CONCLUSION: Image quality, except regarding noise characteristics, and acceptance by radiologists were better by DLR than MBIR in low-dose CE-APCT by UHRCT.

Improved delineation of CT virtual bronchoscopy by ultrahigh-resolution CT: comparison among different reconstruction parameters.

PURPOSE: We compared the maximal recognizable bronchial bifurcation order (MRBBO) in CT virtual bronchoscopy (CTVB) using ultrahigh-resolution CT (UHRCT) and different reconstruction parameters. MATERIALS AND METHODS: We enrolled 38 patients undergoing noncontrast chest CT by UHRCT and reconstructed CTVB utilizing 3 different combinations of reconstruction parameters, as classified into Group A (matrix size, 512; slice thickness, 1.0 mm), Group B (matrix size, 512; slice thickness, 0.5 mm), and Group C (matrix size, 1024; slice thickness, 0.25 mm). In right S1, left S1 + 2, and both S3 and S10, two reviewers counted the number of consecutively identified bronchial bifurcations to compare MRBBO among these groups using Kruskal-Wallis test. RESULTS: In these segments, MRBBO increased from Group A to C. MRBBO was significantly higher in Group C than in both Groups A and B in all the segments except left S10 (P < 0.05 for all). In left S10, it was significantly higher in Group C than in Group A (P < 0.05) but comparable between Groups B and C (P = 0.122). CONCLUSIONS: MRBBO is higher in CTVB by UHRCT utilizing 1024-matrix size and 0.25-mm thickness than parameters currently recommended for CTVB (matrix size, 512; slice thickness, 0.5-1.0 mm).