Importance of imaging-acquisition protocol and post-processing analysis for extracellular volume fraction assessment by computed tomography

BackgroundComputed tomography angiography (CTA) assessment of myocardial extracellular volume fraction (CT-ECV) is feasible, although the protocols for imaging acquisition and post-processing methodology have varied. We aimed to identify a pragmatic protocol for CT-ECV assessment encompassing both imaging acquisition and post-processing methodologies to facilitate its clinical implementation.MethodsWe evaluated consecutive patients with severe aortic stenosis undergoing evaluation for transcatheter aortic valve replacement (TAVR). Pre-contrast and 3-min-delayed CTA were obtained in systole using either helical prospective-ECG-triggered (high-pitch) or axial sequential-ECG-gated acquisition, adding to standard TAVR CTA protocol. Using a dedicated software for co-registration of CTA datasets, three methodologies for ECV measurement were evaluated: (1) mid-septum region of interest (Septal ECV), (2) averaged-global ECV (Global ECV) encompassing 16-AHA segments, and (3) average of septal and lateral segments (Averaged ECVsep and Averaged ECVlat).ResultsAmong the 142 patients enrolled (median ​= ​81 years, 44% females), 8 were excluded due to significant imaging artifacts precluding Global ECV assessment. High-pitch scan mode was performed in 68 patients (48%). Suboptimal image quality for Global ECV assessment was associated with high-pitch scan mode (odds ratio: OR ​= ​2.26, p ​= ​0.036), along with the presence of intracardiac leads (OR ​= ​4.91, p ​= ​0.002), and BMI≥35 ​kg/m² (OR ​= ​2.80, p ​= ​0.026). Septal ECV [median ​= ​29.4%] and Averaged ECVsep [29.0%] were similar (p ​= ​0.108), while Averaged ECVlat [27.5%] was lower than Averaged ECVsep (p ​< ​0.001), resulting in lower Global ECV [28.6%].ConclusionsMyocardial CT-ECV assessment is feasible using a systolic sequential acquisition pre-contrast, and similar additional 3-min delayed scan. Septal ECV measurement provides similar values to Global ECV and is equally reproducible.     

Feasibility of extracellular volume fraction calculation using myocardial CT delayed enhancement with low contrast media administration

BackgroundMyocardial extracellular volume fraction (ECV) derived from CT delayed enhancement (CTDE) may allow assessment of diffuse myocardial fibrosis. However, the amount of contrast medium required for ECV estimation has not been established. Since ECV estimation by CT is typically performed in combination with coronary CT angiography (CCTA) in clinical settings, we aimed to investigate whether reliable ECV estimation is possible using the contrast dose optimized for CCTA without additional contrast administration.MethodsTwenty patients with known or suspected coronary artery disease who underwent CTDE with a dual-source scanner using two protocols (Protocols A and B) within 2 years were retrospectively enrolled. In Protocol A, CTDE was obtained with 0.84 ml/kg of iopamidol (370 mgI/ml) injected for CCTA. In Protocol B, stress CT perfusion imaging, which requires 40 ml of contrast medium, was added to Protocol A. ECV values calculated from the two protocols were compared.ResultsDespite the different contrast doses, no significant difference in mean myocardial ECV was seen between Protocols A and B at the patient level (28.7 ± 4.3% vs. 28.7 ± 4.4%, respectively, P = 0.868). Excellent correlations in ECV were seen between the two protocols (r = 0.942, P < 0.001). Bland-Altman analysis showed slight bias (+0.06%), within a 95% limit of agreement of −2.9% and 3.0%. The coefficient of variation was 5.2%.ConclusionReliable ECV estimation can be achieved with the contrast doses optimized for CCTA. Despite the differing contrast administration schemes and doses, ECV values calculated from the two protocols showed excellent agreement, indicating the robustness of ECV estimation by CT.     

The direct costs of coronary CT angiography relative to contrast-enhanced thoracic CT: Time-driven activity-based costing

BackgroundCoronary CT angiography (CCTA) and contrast-enhanced thoracic CT (CECT) are distinctly different diagnostic procedures that involve intravenous contrast-enhanced CT of the chest. The technical component of these procedures is reimbursed at the same rate by the Centers for Medicare and Medicaid Services (CMS). This study tests the hypothesis that the direct costs of performing these exams are significantly different.MethodsDirect costs for both procedures were measured using a time-driven activity-based costing (TDABC) model. The exams were segmented into four phases: preparation, scanning, post-scan monitoring, and image processing. Room occupancy and direct labor times were collected for scans of 54 patients (28 CCTA and 26 CECT studies), in seven medical facilities within the USA and used to impute labor and equipment cost. Contrast material costs were measured directly. Cost differences between the exams were analyzed for significance and variability.ResultsMean CCTA duration was 3.2 times longer than CECT (121 and 37 ​min, respectively. p ​< ​0.01). Mean CCTA direct costs were 3.4 times those of CECT ($189.52 and $55.28, respectively, p ​< ​0.01). Both labor and capital equipment costs for CCTA were significantly more expensive (6.5 and 1.8-fold greater, respectively, p ​< ​0.001). Segmented by procedural phase, CCTA was both longer and more expensive for each (p ​< ​0.01). Mean direct costs for CCTA exceeded the standard CMS technical reimbursement of $182.25 without accounting for indirect or overhead costs.ConclusionThe direct cost of performing CCTA is significantly higher than CECT, and thus reimbursement schedules that treat these procedures similarly undervalue the resources required to perform CCTA and possibly decrease access to the procedure.     

Potential of employing a quantum iterative reconstruction algorithm for ultra-high-resolution photon-counting detector CT of the hip

IntroductionThis study investigated the image quality of a new quantum iterative reconstruction algorithm (QIR) for high resolution photon-counting CT of the hip.MethodsUsing a first-generation photon-counting CT scanner, five cadaveric specimens were examined with ultra-high-resolution protocols matched for radiation dose. Images were post-processed with a sharp convolution kernel and five different strength levels of iterative reconstruction (QIR 0 – QIR 4). Subjective image quality was rated independently by three radiologists on a five-point scale. Intraclass correlation coefficients (ICC) were computed for assessing interrater agreement. Objective image quality was evaluated by means of contrast-to-noise-ratios (CNR) in bone and muscle tissue.ResultsFor osseous tissue, subjective image quality was rated best for QIR 2 reformatting (median 5 [interquartile range 5–5]). Contrarily, for soft tissue, QIR 4 received the highest ratings among compared strength levels (3 [3–4]). Both ICC_bone (0.805; 95% confidence interval 0.711–0.877; p < 0.001) and ICC_muscle (0.885; 0.824–0.929; p < 0.001) suggested good interrater agreement. CNR in bone and muscle tissue increased with ascending strength levels of iterative reconstruction with the highest results recorded for QIR 4 (CNR_bone 29.43 ± 2.61; CNR_muscle 8.09 ± 0.77) and lowest results without QIR (CNR_bone 3.90 ± 0.29; CNR_muscle 1.07 ± 0.07) (all p < 0.001).ConclusionReconstructing photon-counting CT data with an intermediate QIR strength level appears optimal for assessment of osseous tissue, whereas soft tissue analysis benefitted from applying the highest strength level available.Implications for practiceQuantum iterative reconstruction technique can enhance image quality by significantly reducing noise and improving CNR in ultra-high resolution CT imaging of the hip.     

Diagnostic Performance of CT-Guided Bone Biopsies in Patients with Suspected Osteomyelitis of the Appendicular and Axial Skeleton with a Focus on Clinical and Technical Factors Associated with Positive Microbiology Culture Results

PurposeTo assess diagnostic performance of CT-guided percutaneous needle bone biopsy (CTNBB) in patients with suspected osteomyelitis and analyze whether certain clinical or technical factors were associated with positive microbiology results.Materials and MethodsAll CTNBBs performed in a single center for suspected osteomyelitis of the appendicular and axial skeleton during 2003–2018 were retrospectively reviewed. Specific inclusion criteria were clinical and radiologic suspicion of osteomyelitis. Standard of reference was defined using outcome of surgical histopathology and microbiology culture and clinical and imaging follow-up. Technical and clinical data (needle size, comorbidities, clinical factors, laboratory values, blood cultures) were collected. Logistic regression was performed to assess associations between technical and clinical data and microbiology biopsy outcome.ResultsA total of 142 CTNBBs were included (46.5% female patients; age ± SD 46.10 y ± 22.8), 72 (50.7%) from the appendicular skeleton and 70 (49.3%) from the axial skeleton. CTNBB showed a sensitivity of 42.5% (95% confidence interval [CI], 32.0%–53.6%) in isolating the causative pathogen. A higher rate of positive microbiology results was found in patients with intravenous drug use (odds ratio [OR] = 5.15; 95% CI, 1.2–21.0; P = .022) and elevated white blood cell count ≥ 10 × 10⁹/L (OR = 3.9; 95% CI, 1.62–9.53; P = .002). Fever (≥ 38°C) was another clinical factor associated with positive microbiology results (OR = 3.6; 95% CI, 1.3–9.6; P = .011).ConclusionsCTNBB had a low sensitivity of 42.5% for isolating the causative pathogen. Rate of positive microbiology samples was significantly higher in patients with IV drug use, elevated white blood cell count, and fever.     

Impact of the Ablative Margin on Local Tumor Progression after Radiofrequency Ablation for Lung Metastases from Colorectal Carcinoma: Supplementary Analysis of a Phase II Trial (MLCSG-0802)

PurposeTo explore what extent of ablative margin depicted by computed tomography (CT) immediately after radiofrequency (RF) ablation is required to reduce local tumor progression (LTP) for colorectal cancer (CRC) lung metastases.Materials and MethodsThis retrospective study was undertaken as a supplementary analysis of a previous prospective trial. Seventy patients (49 men and 21 women; mean age ± standard deviation, 64.9 years ± 10.6 years) underwent RF ablation for CRC lung metastases, and 95 tumors that were treated in the trial and followed up with CT at least 12 months after RF ablation were evaluated. The mean tumor size was 1.0 cm ± 0.5 cm. The ablative margin was estimated as the shortest distance between the outer edge of the tumor and the surrounding ground-glass opacity on CT obtained immediately after RF ablation. The impact of the ablative margin on LTP was evaluated using logistic regression analysis. Multivariate logistic regression analysis was also performed to identify the risk factors for LTP. The result was validated with multivariate logistic regression applying a bootstrap method (1,000 times resampling).ResultsThe mean ablative margin was 2.7 mm ± 1.3 (range, 0.4–7.3 mm). LTP developed in 6 tumors (6%, 6/95) 6–19 months after RF ablation. The LTP rate was significantly higher when the margin was less than 2 mm (P = .023). A margin of <2 mm was also found to be a significant factor for LTP (P = .048) on multivariate analysis and validated using the bootstrap method (P = .025).ConclusionsAn ablative margin of at least 2 mm is important to reduce LTP after RF ablation for CRC lung metastases.     

Computed Tomography Evaluation of In Vivo Pulmonary Cryoablation Zone Sizes

PurposeTo evaluate ablation zone sizes in patients undergoing pulmonary tumor cryoablation with 14-gauge cryoablation probes.Materials and MethodsA single-center retrospective analysis of all consecutive patients who underwent cryoablation of pulmonary tumors with 1 or more 14-gauge probes (August 2017 to June 2020) was performed. Intraprocedural and 1–2-month postprocedural chest computed tomography (CT) scans were evaluated to characterize pulmonary lesions, ice balls, and ablation zones. Single-probe 14-gauge ablation zone volumes were compared with manufacturer reference isotherms and single- and 2-probe ablation zones from a prior investigation of 17-gauge probes. Overall survival and local recurrence–free survival were calculated to 3 years.ResultsForty-seven pulmonary malignancies in 42 patients (women, 50%; mean age, 75.2 years ± 11.5) underwent cryoablation with 1 (n = 35), 2 (n = 10), or 3 (n = 2) cryoablation probes. One- to 2-month follow-up CT images were available for 30 of the 42 patients. The mean cryoablation zone volumes at 1–2 months when 1 (n = 21), 2 (n = 8), and 3 (n = 1) probes were used were 5.0 cm³ ± 2.3, 37.5 cm³ ± 20.5, and 28.4 cm³, respectively. The mean single-probe follow-up ablation zone volume was larger than that previously reported for 17-gauge probes (3.0 cm³ ± 0.3) (P < .001) but smaller than manufacturer-reported isotherms (11.6 cm³ for ?40 °C isotherm) and the 2-probe ablation zone volume with 17-gauge devices (12.9 cm³ ± 2.4) (for all, P < 001). The 3-year overall survival and local recurrence–free survival were 69% (95% confidence interval [CI], 53%–89%) and 87% (95% CI, 74%–100%), respectively.ConclusionsFourteen-gauge probes generate larger ablation volumes than those generated by 17-gauge probes. Manufacturer-reported isotherms are significantly larger than actual cryoablation zones. Cryoablation can attain low rates of local recurrence.     

Baseline global longitudinal strain by computed tomography is associated with post transcatheter aortic valve replacement outcomes

BackgroundsSubclinical myocardial dysfunction detected by global longitudinal strain (GLS) using echocardiography is associated with poor outcomes in patients with severe aortic stenosis (AS) despite normal left ventricular ejection fraction (LVEF). Computed tomography angiography derived GLS (CTA-GLS) has recently shown to be feasible, however the prognostic value remains unclear in severe AS patients treated with transcatheter aortic valve replacement (TAVR).MethodsWe analyzed consecutive patients who underwent TAVR with pre-TAVR retrospective gated acquisition CTA study with adequate image quality covering the entire left ventricle. CTA-GLS analysis was performed using 2D CT-Cardiac Performance Analysis prototype software (TomTec GmbH). Kaplan-Meier and Cox regression analyses were performed to evaluate the association of baseline CTA-GLS with all-cause mortality and a composite outcome of all-cause death and hospitalization for heart failure after TAVR.ResultsA total of 223 patients were included (mean age 83.5 ± 6.8 years, 45.7% female, mean CTA-LVEF 50.7 ± 14.5%). During a median follow-up of 32 months, 81 all-cause deaths and 134 composite outcomes occurred. When compared to patients with normal LVEF (≥50%) and preserved CTA-GLS (≤-20.5%), patients with normal LVEF but reduced CTA-GLS (>-20.5%) had higher all-cause mortality (Chi-square 6.89, p = 0.032) and the risk of composite outcome (Chi-square 7.80, p = 0.020) which was no different than those with impaired LVEF. Reduced CTA-GLS was independently associated with all-cause mortality (HR 1.71, 95% CI 1.01–2.90, p = 0.049) and the risk of composite outcome (HR 1.51, 95% CI 1.01–2.25, p = 0.044) on multivariable Cox regression analysis.ConclusionsReduced CTA-GLS provides independent prognostic value above multiple clinical and echocardiographic characteristics.     

Evaluation of the Benefit of Extended Catheter-Directed Thrombolysis with Serial Angiography for Acute Pulmonary Embolism

PurposeTo evaluate whether extended catheter-directed thrombolysis (CDT) with repeat visits to the angiography suite provide added benefit in treatment of acute pulmonary embolism (PE).Materials and MethodsThis was a retrospective review of CDT procedures performed for acute PE in 156 patients (age 56.1 y ± 15.3, 46.2% women) between 2009 and 2019. All patients underwent at least 1 follow-up visit to the angiography suite for evaluation of pulmonary artery pressure (PAP) and thrombus burden (Miller score) before termination (111/156, 71.2%) or continuation of CDT (45/156, 28.8%).ResultsPatients who had CDT extended beyond the first follow-up visit required a higher total dose of tissue plasminogen activator (40.7 mg ± 14.3 vs 22.6 mg ± 9.9, P < .001) to achieve a similar final Miller score (6.4 ± 3.8 vs 7.6 ± 3.9, P = .1) and a similar reduction in systolic PAP (?14.4 mm Hg ± 10.2 vs ?12.6 mm Hg ± 11.9, P = .6). The initial Miller scores were similar in both groups (19.7 ± 5.8 vs 19 ± 4, P = .4) but were significantly higher during the first follow-up visit (after 18 hours ± 5.5 vs 20 hours ± 4.8, P = .06) in patients requiring multiple follow-up visits (12.2 ± 5 vs 7.6 ± 3.9, P < .001). Multiple regression analyses identified heart rate > 100 beats/min and systolic PAP > 55 mm Hg as associated with the need for extended CDT. Extended CDT did not result in a higher hemorrhagic complication rate (1/45 vs 6/111, P = .7).ConclusionsPatients presenting with higher heart rates and systolic PAP may benefit from extended CDT to achieve similar reductions in PAP and thrombus burden, without clear added risk of hemorrhage.     

Juxtametallic Bipolar Bone Radiofrequency Ablation: Thermal Monitoring in an Ex-Vivo Model with Specimen MRI and Histopathologic Correlation

PurposeTo measure the ablation zone temperature and nontarget tissue temperature during radiofrequency (RF) ablation in bone containing metal instrumentation versus no metal instrumentation (control group).Materials and MethodsEx vivo experiments were performed on 15 swine vertebrae (control, n = 5; titanium screw, n = 5; stainless steel screw, n = 5). Screws and RF ablation probe were inserted identically under fluoroscopy. During RF ablation (3 W, 5 minutes), temperature was measured 10 mm from RF ablation centerpoint and in muscle contacting the screw. Magnetic resonance (MR) imaging, gross pathologic, and histopathologic analyses were performed on 1 specimen from each group.ResultsAblation zone temperatures at 2.5 and 5 minutes increased by 12.2 °C ± 2.6 °C and 21.5 °C ± 2.1 °C (control); 11.0 °C ± 4.1 °C and 20.0 °C ± 2.9 °C (juxta-titanium screw), and 10.0 °C ± 3.4 °C and 17.2 °C ± 3.5 °C (juxta–stainless steel) screw; differences among groups did not reach significance by analysis of variance (P = .87). Mixed-effects linear regression revealed a statistically significant increase in temperature over time in all 3 groups (4.2 °C/min ± 0.4 °C/min, P < .001). Compared with the control, there was no significant difference in the temperature change over time for titanium (?0.3 °C/min ± 0.5 °C/min, P = .53) or steel groups (?0.4 °C/min ± 0.5 °C/min, P = .38). The mean screw temperature at the final time point did not show a statistically significant change compared with baseline in either the titanium group (?1.2 °C ± 2.3 °C, P = .50) or steel group (2.6 °C ± 2.9 °C, P = .11). MR imaging and pathologic analyses revealed homogeneous ablation without sparing of the peri-hardware zones.ConclusionsAdjacent metallic instrumentation did not affect the rate of or absolute increase in temperature in the ablation zone, did not create peri–metallic ablation inhomogeneities, and did not result in significant nontarget heating of muscle tissue in contact with the metal instrumentation.     

Single-Use versus Reusable Endoscopes for Percutaneous Biliary Endoscopy with Lithotripsy: Technical Metrics,Clinical Outcomes,and Cost Comparison

PurposeTo compare procedure and fluoroscopy time, technical and clinical success, and costs between single-use and reusable endoscopes in patients undergoing percutaneous biliary endoscopy (PBE) with lithotripsy.Material and MethodsThirty-four patients (67 procedures) were retrospectively included in the study. The patients were treated with PBE for gallstone removal from October 24, 2014, to February 12, 2020, using reusable (28 procedures) or single-use (39 procedures) endoscopes. The procedure time, fluoroscopy time, technical success rate (accessing the biliary system and locating the gallstone), clinical success rate (at least partial gallstone removal), complication rate, and cost of use were compared between the procedures.ResultsThe mean (± standard deviation) procedure time was not significantly different between single-use (136 minutes ± 45) and reusable endoscopes (136 minutes ± 51) (P = .47). The mean fluoroscopy time was significantly shorter for single-use endoscopes (11 minutes ± 8.4) than for reusable endoscopes (18 minutes ± 12) (P = .01). When comparing single-use versus reusable endoscopes, the technical success (95% [n = 37] vs 93% [n = 26]) and the clinical success (90% [n = 35] vs 75% [n = 21]) rates were not significantly different (both, P > .05). Only 1 complication was noted in the reusable endoscope group (P = .42). The cost per case was lower for single-use ($1,500) than for reusable ($3,987) endoscope procedures, primarily due to differences in capital costs and repair costs.ConclusionsSingle-use endoscopes offer the potential for lower patient radiation exposure and lower cost per case, which may reduce the financial barriers to offering PBE in interventional radiology practices. The clinical and technical success rates did not differ by endoscope type.     

Prostatic Artery Embolization Using 100–300-μm Trisacryl Gelatin Microspheres to Treat Lower Urinary Tract Symptoms Attributable to Benign Prostatic Hyperplasia: A Single-Center Outcomes Analysis with Medium-Term Follow-up

PurposeTo report medium-term outcomes of prostatic artery embolization (PAE) using 100–300-μm trisacryl gelatin microspheres to treat lower urinary tract symptoms (LUTS) from benign prostatic hyperplasia (BPH) and to evaluate how cone-beam computed tomography-measured prostate gland volume (PGV), median lobe enlargement (MLE), age, and Charlson Comorbidity Index (CCI) affect these results.Materials and MethodsSeventy-four consecutive patients who underwent PAE from April 2014 through August 2018 were retrospectively reviewed. Patients had International Prostate Symptom Score (IPSS) >12, Quality of Life (QoL) score >2, prostate gland volume (PGV) >40 mL, age older than 45 years, and medical therapy failure. Twelve patients were excluded for bladder pathology or prostate cancer. Patients (n = 62, age = 71.8 ± 9.3 years, CCI = 3.5 ± 1.7, PGV = 174 ± 110 mL) had pre-procedure IPSS = 22.4 ± 5.6, QoL score = 4.4 ± 0.9, and post-void residual (PVR) = 172 ± 144 mL. Post-procedure values were compared to baseline at 1, 3, 6, 12, and 24 months. Associations between outcomes and PGV, MLE, age, and CCI were evaluated. Adverse event recording used Clavien-Dindo classification.ResultsOne month after PAE (n = 37), IPSS improved to 7.6 ± 5.2 (P < .0001) and QoL score improved to 1.7 ± 1.4 (P < .0001). At 3 months (n = 32), improvements continued, with IPSS = 6.4 ± 5.1 (P < .0001), QoL score = 1.2 ± 1.2 (P < .0001), PVR = 53 ± 41 mL (P < .001), and PGV = 73 ± 38 mL (P < .0001). Results were sustained at 6 months (n = 35): IPSS = 6.4 ± 4.1 (P < .0001), QoL score = 1.2 ± 1.2 (P < .0001), PVR = 68 ± 80 mL (P < .0001), PGV = 60 ± 19 mL (P < .001). At 12 months, patients (n = 26) had IPSS = 7.3 ± 5.5 (P < .0001), QoL score = 1.2 ± 0.8 (P <.0001), PVR = 89 ± 117 mL (P < .0001), PGV = 60 ± 48 mL (P < .01). At 24 months, patients (n = 8) had IPSS = 8.0 ± 5.4 (P < .0001), QoL score = 0.7 ± 0.5 (P < .0001), PVR = 91 ± 99mL (P = 0.17), and PGV = 30 ± 5mL (P = .11). Improvements were independent of PGV, MLE, age, and CCI. Two grade II urinary infections occurred.ConclusionsPAE with 100–300-μm microspheres produced sustained substantial improvements in LUTS, PGV, and PVR, which were independent of baseline PGV, MLE, age, or CCI.     

Yttrium-90 Radiation Segmentectomy of Hepatocellular Carcinoma: A Comparative Study of the Effectiveness,Safety, and Dosimetry of Glass-Based versus Resin-Based Microspheres

PurposeTo evaluate the differences in safety, effectiveness, and dosimetry between glass-based and resin-based ablative yttrium-90 (⁹⁰Y) transarterial radioembolization (TARE) of hepatocellular carcinoma (HCC).Materials and MethodsUsing the modified Response Evaluation Criteria in Solid Tumors and Common Terminology Criteria for Adverse Events, both tumor response and adverse events (AEs) were assessed at 3 months after ⁹⁰Y-TARE. Post procedure ⁹⁰Y-bremsstrahlung single-photon emission computed tomography/computed tomography voxel-based dosimetry analysis was used to create tumor dose (TD) and normal tissue dose (NTD) volume histograms, and to calculate tumor particle loading and specific activity. The TD and NTD receiver operating characteristic curves evaluated the dose threshold able to predict objective (partial or complete) and complete tumor responses in addition to any-grade and grade ≥3 AE incidences. The chi-square test and Student t-test were used to assess variable differences where appropriate.ResultsBetween 2019 and 2020, 81 patients with HCC (20 in the resin-based cohort and 61 in the glass-based cohort) underwent ablative ⁹⁰Y-TARE. The resin-based cohort had more males (89% vs 65%, P = .03), lower tumor-to-normal ratio (1.81 ± 0.39 vs 2.22 ± 0.94, P = .03), higher tumor particle loading (40,172 particles/mL ± 28,039 vs 17,081 particles/mL ± 12,555, P = .0001), lower specific activity (158 Bq/particle ± 3 vs 1,058 Bq/particle ± 331, P = .001), and lower mean TD (308 Gy ± 210 vs 794 Gy ± 523, P = .0002) than the glass-based cohort. No significant differences in baseline characteristics or posttreatment AEs were noted. The overall objective and complete response rates were 85% (95% resin-based vs 82% glass-based; P = .1) and 65% (95% resin-based vs 56% glass-based; P = .003), respectively. The mean TD thresholds able to predict the objective and complete responses were 176 Gy and 247 Gy for resin-based radioembolization and 290 Gy and 481 Gy for glass-based radioembolization, respectively. A maximum NTD of 999 Gy predicted any-grade AEs in glass-based ablative ⁹⁰Y-TARE.ConclusionsCompared with glass-based ablative ⁹⁰Y-TARE, resin-based ablative ⁹⁰Y-TARE can offer comparable safety and effectiveness profiles for patients with HCC. The impact of the significantly different tumor particle loading, particle specific activities, and delivered TDs on tumor response outcomes merits further investigation.     

Sex-Related Differences in the Long-Term Outcomes of Patients with Femoropopliteal Arterial Disease Treated with the IN.PACT Drug-Coated Balloon in the IN.PACT SFA Randomized Controlled Trial: A Post Hoc Analysis

PurposeTo evaluate sex-related disparities in long-term outcomes of patients with peripheral artery disease (PAD) treated with IN.PACT drug-coated balloon (DCB) or percutaneous transluminal angioplasty (PTA).Materials and MethodsA post hoc analysis of the IN.PACT SFA trial was performed. Participants with Rutherford Clinical Classification 2–4 PAD and femoropopliteal artery lesions up to 18 cm long were randomly assigned to treatment with DCB (n = 220) or PTA (n = 111). Effectiveness outcomes were evaluated, including 36-month primary patency (freedom from binary restenosis and freedom from clinically driven [CD] target lesion revascularization [TLR]).ResultsIn the DCB group, women were significantly older (69.4 y ± 9.9) than men (66.4 y ± 9.1; P = .025). Mean reference vessel diameter (RVD) was significantly smaller in women (4.4 mm ± 0.68) compared with men (4.8 mm ± 0.89, P < .001). Primary patency was 65.4% in women and 71.8% in men (P = .302). Freedom from CD-TLR was 81.1% in women and 86.4% in men (P = .285). Women treated with PTA were older (70.4 y ± 8.3) than men (66.9 y ± 9.5; P = .063). Mean RVD was significantly smaller in women (4.2 mm ± 0.77) compared with men (4.9 mm ± 0.77, P < .001). Primary patency was 42.3% in women and 46.7% in men (P = .551). Freedom from CD-TLR was 59.4% in women and 75.5% in men (P = .109). No significant differences were noted in safety and mortality outcomes.ConclusionsIn both groups, women were older and had smaller vessels. Particularly in the PTA group, women had worse clinical outcomes, though not reaching statistical significance. Further evaluation is necessary to understand the disparate nature of disease progression and outcomes following endovascular treatment in women compared with men.     

Dynamic Contrast-Enhanced MR Imaging Evaluation of Perfusional Changes and Ablation Zone Size after Combination Embolization and Ablation Therapy

PurposeThe objectives of this study were to assess the utility of dynamic contrast-enhanced magnetic resonance (MR) imaging in quantifying parenchymal perfusional changes after embolization and to characterize the association between pharmacokinetic (PK) parameters and final microwave ablation volume.Materials and MethodsPK parameters from dynamic contrast-enhanced MR imaging were used to quantify perfusional changes in the liver after transarterial embolization of the right or left lobe in a swine liver model (n = 5). Each animal subject subsequently underwent microwave ablation (60 W for 5 minutes) of the embolized and nonembolized liver lobes. Changes in PK parameters from dynamic contrast-enhanced MR imaging were correlated with their respective final microwave ablation volumes in each liver lobe.ResultsMicrowave ablation volumes of embolized liver lobes were significantly larger than those of nonembolized liver lobes (28.0 mL ± 6.2 vs 15.1 mL ± 5.2, P < .001). PK perfusion parameters were significantly lower in embolized liver lobes than in nonembolized liver lobes (K^trans = 0.69 min^?1 ± 0.15 vs 1.52 min^?1 ± 0.37, P < .001; k_ep = 0.69 min^?1 ± 0.19 vs 1.54 min^?1 ± 0.42, P < .001). There was a moderate but significant correlation between normalized k_ep and ablation volume, with each unit increase in normalized k_ep corresponding to a 9.8-mL decrease in ablation volume (P = .035).ConclusionsPK-derived parameters from dynamic contrast-enhanced MR imaging can be used to quantify perfusional changes after transarterial embolization and are directly inversely correlated with final ablation volume.     

4D Flow MR Imaging to Improve Microwave Ablation Prediction Models: A Feasibility Study in an In Vivo Porcine Liver

PurposeTo characterize the effect of hepatic vessel flow using 4-dimensional (4D) flow magnetic resonance (MR) imaging and correlate their effect on microwave ablation volumes in an in vivo non-cirrhotic porcine liver model.Materials and MethodsMicrowave ablation antennas were placed under ultrasound guidance in each liver lobe of swine (n = 3 in each animal) for a total of 9 ablations. Pre- and post-ablation 4D flow MR imaging was acquired to quantify flow changes in the hepatic vasculature. Flow measurements, along with encompassed vessel size and vessel-antenna spacing, were then correlated with final ablation volume from segmented MR images.ResultsThe linear regression model demonstrated that the preablation measurement of encompassed hepatic vein size (β = –0.80 ± 0.25, 95% confidence interval [CI] –1.15 to –0.22; P = .02) was significantly correlated to final ablation zone volume. The addition of hepatic vein flow rate found via 4D flow MRI (β = –0.83 ± 0.65, 95% CI –2.50 to 0.84; P = .26), and distance from antenna to hepatic vein (β = 0.26 ± 0.26, 95% CI –0.40 to 0.92; P = .36) improved the model accuracy but not significantly so (multivariate adjusted R² = 0.70 vs univariate (vessel size) adjusted R² = 0.63, P = .24).ConclusionsHepatic vein size in an encompassed ablation zone was found to be significantly correlated with final ablation zone volume. Although the univariate 4D flow MR imaging-acquired measurements alone were not found to be statistically significant, its addition to hepatic vein size improved the accuracy of the ablation volume regression model. Pre-ablation 4D flow MR imaging of the liver may assist in prospectively optimizing thermal ablation treatment.     

Increased coronary pericoronary adipose tissue attenuation in diabetic patients compared to non-diabetic controls: A propensity score matching analysis

BackgroundPericoronary adipose tissue (PCAT) attenuation is an indicator of active inflammation of perivascular adipose tissue, which is supposed to increase in diabetic patients. We aimed to investigate the PCAT attenuation values and high-risk plaque (HRP) features in diabetic and non-diabetic subjects with different stenotic extents.MethodsConsecutive type 2 diabetes patients and non-diabetic patients with chest pain and intermediate pre-test probability of coronary artery disease (CAD) were prospectively enrolled and underwent coronary computed tomography angiography (CCTA). At per-patient level, PCAT attenuation values of three major epicardial coronary vessels, as well as HRP features were measured. PCAT attenuation values and HRP features were compared between diabetic and non-diabetic subjects according to the presence or absence of obstructive stenosis.Results1700 patients (mean age: 65.5 ?± ?11.7, 940 males) were divided into two groups according to presence of obstructive stenosis on CCTA. Propensity score matching was performed in further analysis. RCA_PCAT was significantly higher in diabetic subjects than that in non-diabetic subjects, regardless of the presence of obstructive stenosis (?83.60 ?± ?9.51 HU vs. ?88.58 ?± ?9.37 HU, p ?< ?0.001) or absence of obstructive stenosis (?83.70 ?± ?10.32 HU vs. ?88.76 ?± ?8.28 HU, p ?< ?0.001). In contrast, HRP features were more commonly presented in diabetic patients with obstructive stenosis than in those without obstructive stenosis. According to subgroup analysis based on acquisition tube voltage, RCA_PCAT was the only parameter showing consistent difference between diabetic and non-diabetic patients.ConclusionsRCA_PCAT was significantly higher in diabetic patients than that in non-diabetic patients regardless of stenotic severity and plaque vulnerability.     

Prognostic Factors for Local Recurrence after Cryoablation of Desmoid Tumors

PurposeTo determine the risk factors for local of adult patients treated for desmoid tumors by cryoablation.Materials and MethodsEighty-four patients treated for nonabdominopelvic desmoid tumors by cryoablation from July 2012 to July 2020 were included in a retrospective study. The population was composed of 64 women (76.19%) and 20 men (23.81%), aged from 16 to 75 years (median, 35 years ± 14.25). Each patient underwent preprocedural gadolinium-enhanced magnetic resonance imaging and was followed up to 36 months with the same technique. Clinical features, such as tumor size and previous treatment, epidemiological features, and the technical parameters of cryoablation, were studied.ResultsLocal relapse was found in 19 (22.62%) of 84 patients. The 12-, 24-, and 36-month progression-free survival rates were 89% (95% confidence interval [CI], 79–94), 74% (95% CI, 60–83), and 68% (95% CI, 53–79), respectively. In univariate analysis, significant prognostic factors associated with local recurrence were non–abdominal wall location (P = .042), debulking strategy (P = .0105), risk of visceral injury (P = .034) or peripheral nerve injury during cryoablation (P = .033), previous radiation therapy (P = .043), and treatment before 2016 (P = .008). In multivariate analysis, abdominal wall tumors displayed the best outcome, whereas the neck and trunk showed a high rate of recurrence (hazard ratio, 7.307 [95% CI, 1.396–38.261]).ConclusionsThe local recurrence of desmoid tumors after cryoablation depends on a number of prognostic factors, in particular, a non–abdominal wall location of the tumor and previous local treatment such as surgery or radiation therapy.     

Association between Baseline Osteoarthritic Features on MR Imaging and Clinical Outcome after Genicular Artery Embolization for Knee Osteoarthritis

PurposeTo explore the association between baseline osteoarthritis (OA)-related magnetic resonance (MR) imaging features and pain reduction after genicular artery embolization (GAE) in patients with mild-to-moderate symptomatic knee OA resistant to conservative therapy.Materials and MethodsThis was a retrospective analysis of patients with mild-to-moderate symptomatic knee OA treated with GAE using imipenem-cilastatin sodium. The clinical outcome was scored at baseline and 6 months after treatment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). MR images were scored using the MR imaging osteoarthritis knee score. Linear regression was used to evaluate associations of before-treatment MR imaging scores with WOMAC_pain and WOMAC_total reduction after 6 months.ResultsFifty-four patients (22.2% male; median age, 69.4 years; median WOMAC_pain at baseline, 12) were evaluated. Of all OA features scored, a higher cartilage full-thickness defect score showed the strongest association with less reduction of both WOMAC_pain (B,?0.63 [95% confidence interval (CI), ?0.91 to ?0.34]; P < .001) and WOMAC_total scores (B, ?1.77 [95% CI, ?2.87 to ?0.67]; P < .001) following treatment. The presence of grade 2–3 effusion synovitis (B, ?2.99 [95% CI, ?5.39 to ?0.60]) bone marrow lesions (B, ?0.52 [95% CI, ?0.86 to ?0.19]), osteophytes (B, ?0.21 [95% CI, ?0.36 to ?0.06]), and cartilage defect surface area score (B, ?0.25 [95% CI ?0.42 to ?0.08]) all showed a significant association with less WOMAC_pain reduction (all P < .05).ConclusionsIn patients with mild-to-moderate symptomatic knee OA treated with GAE, the presence and severity of full-thickness cartilage defects, effusion synovitis, bone marrow lesions, osteophytes, and cartilage surface area scores at baseline are associated with less favorable clinical outcomes at 6 months.     

Age related compositional plaque burden by CT in patients with future ACS

BackgroundWe examined age differences in whole-heart volumes of non-calcified and calcified atherosclerosis by coronary computed tomography angiography (CCTA) of patients with future ACS.MethodsA total of 234 patients with core-lab adjudicated ACS after baseline CCTA were enrolled. Atherosclerotic plaque was quantified and characterized from the main epicardial vessels and side branches on a 0.5 ?mm cross-sectional basis. Calcified plaque and non-calcified plaque were defined by above or below 350 Hounsfield units. Patients were categorized according to their age by deciles. Also, coronary artery calcium scores (CACS) were evaluated when available.ResultsPatients were on average 62.2 ?± ?11.5 years old. On the pre-ACS CCTA, patients showed diffuse, multi-site, predominantly non-obstructive atherosclerosis across all age categories, with plaque being detected in 93.5% of all ACS cases. The proportion calcified plaque from the total plaque burden increased significantly with older presentation (10% calcification in those <50 years, and 50% calcification in those >80 years old). Patients with ACS <50 years had remarkably lower atherosclerotic burden compared with older patients, but a high proportion of high risk markers such as low-attenuation plaque. CACS was >0 in 85% of the patients older than 50 years, and in 57% of patients younger than 50 years.ConclusionThe proportion of calcified plaque varied depending on patient age at the time of ACS. Only a small proportion of plaque was calcified when ACS occurred at <50 years old, while this increased gradually with older age. Purely non-calcified atherosclerotic plaque was not uncommon in patients <50 years.