Development of Convolutional Neural Network to Segment Ultrasound Images of Histotripsy Ablation.

OBJECTIVE: Histotripsy is a focused ultrasound therapy that ablates tissue via the action of bubble clouds. It is under investigation to treat a number of ailments, including renal tumors. Ultrasound imaging is used to monitor histotripsy, though there remains a lack of definitive imaging metrics to confirm successful treatment outcomes. In this study, a convolutional neural network (CNN) was developed to segment ablation on ultrasound images. METHODS: A transfer learning approach was used to replace classification layers of the residual network ResNet-18. Inputs to the classification layers were based on ultrasound images of ablated red blood cell phantoms. Digital photographs served as the ground truth. The efficacy of the CNN was compared to subtraction imaging, and manual segmentation of images by two board-certified radiologists. RESULTS: The CNN had a similar performance to manual segmentation, though was improved relative to segmentation with subtraction imaging. Predictions of the network improved over the course of treatment, with the Dice similarity coefficient less than 20% for fewer than 500 applied pulses, but 85% for more than 750 applied pulses. The network was also applied to ultrasound images of ex vivo kidney exposed to histotripsy, which indicated a morphological shift in the treatment profile relative to the phantoms. These findings were consistent with histology that confirmed ablation of the targeted tissue. CONCLUSION: Overall, the CNN showed promise as a rapid means to assess outcomes of histotripsy and automate treatment. SIGNIFICANCE: Data collected in this study indicate integration of CNN image segmentation to gauge outcomes for histotripsy ablation holds promise for automating treatment procedures.

Measurement of the Tumor-to-Normal Ratio for Radioembolization of Hepatocellular Carcinoma: A Prospective Study Comparing 2-Dimensional Perfusion Angiography, Technetium-99m Macroaggregated Albumin, and Yttrium-90 SPECT/CT.

PURPOSE: To calculate the preradioembolic tumor-to-normal (T:N) ratio in hepatocellular carcinoma (HCC) using 2-dimensional (2D) perfusion angiography and compare it with that calculated using technetium-99m macroaggregated albumin (99mTc MAA) single-photon emission computed tomography (SPECT)/computed tomography (CT). MATERIALS AND METHODS: This prospective single-arm study enrolled 15 participants with HCC who underwent 2D perfusion angiography immediately before the enrollment and with the microcatheter located at the same location as 99mTc MAA injection, after which SPECT/CT was performed. Quantitative digital subtraction angiography was used to calculate the area under the curve for the tumor and normal hepatic parenchyma and subsequently calculate the T:N ratio. The T:N ratio was calculated from the 99mTc MAA SPECT/CT and post-yttrium-90 bremsstrahlung SPECT/CT using dosimetry software. RESULTS: The mean participant age was 64.1 years ± 9.8, and the study included 14 (93%) men and 1 (7%) woman. The mean tumor size was 4.1 cm (SD ± 2.4), and all participants received segmental treatments with glass microspheres. The mean T:N ratio calculated by 99mTc MAA SPECT/CT was 2.28 (SD ± 0.89) vs 2.25 (SD ± 0.99) calculated by 2D perfusion angiography (P = .45). For the 13 participants who underwent selective internal radiation therapy (transarterial radioembolization), there was no significant difference between the T:N ratios calculated by 2D perfusion angiography and post-90Y SPECT/CT (2.25 [SD ± 1.05] vs 1.91 [SD ± 0.39]; P = .12). CONCLUSIONS: The T:N ratio calculated by 2D perfusion angiography correlated well with that calculated by 99mTc MAA SPECT/CT.

Transarterial therapies in patients with hepatocellular carcinoma eligible for transarterial embolization: a US cost-effectiveness analysis.

OBJECTIVES: To assess the cost-effectiveness of transarterial radioembolization (TARE) versus conventional transarterial chemoembolization (cTACE) and drug-eluting beads chemoembolization (DEE-TACE) for patients with unresectable early- to intermediate-stage hepatocellular carcinoma (HCC). DESIGN: A cohort-based Markov model with a five-year time horizon was developed to evaluate the cost-effectiveness of the three embolization treatments. Upon entering the model, patients with HCC received either TARE or one of the two other embolization treatments. Patients remained in a "watch and wait" state for tumor downstaging that allowed them to move to health states such as liver transplant, resection, systemic therapies, or cure. Clinical input parameters were retrieved from the published literature, and where values could not be sourced, assumptions were made and validated by clinical experts. Health benefits were quantified using quality-adjusted life years (QALYs). Cost input parameters were obtained from various sources, including the Medicare Cost Report, IBM® Micromedex RED BOOK, and published literature. RESULTS: At five years, TARE was found to be cost-saving (saving $15,779 per person compared to cTACE) and produced 0.33 more QALYs per person than cTACE. TARE cost $13,696 more but produced 0.33 more QALYs than DEE-TACE, with an incremental cost-effectiveness ratio of $41,474 per QALY gained at five years. After accounting for parameter uncertainty, the likelihood of TARE being cost-effective was at least 90% against all comparators at a cost-effectiveness threshold of $100,000 per QALY gained. CONCLUSIONS: TARE produces more QALYs than cTACE and DEE-TACE, with a high probability of being cost-effective against both comparators.

The Barcelona Clinic Liver Cancer guideline recommends the use of transarterial radioembolization (TARE), conventional (cTACE), or drug-eluting bead transarterial chemoembolization (DEE-TACE) for treating hepatocellular carcinoma (HCC). This study evaluated the cost-effectiveness of TARE versus two alternative embolization treatments (cTACE and DEE-TACE) in treating patients with unresectable early- to intermediate-stage HCC.A cohort-based Markov model was developed to analyze the costs and benefits of these treatments from a US healthcare perspective within a 5-year time horizon. A 20-year time horizon was assessed as a scenario. In the model, patients were assigned to receive TARE, cTACE, or DEE-TACE and remained in the "watch and wait" stage for tumor downstaging. Data used in the model was taken from previous studies and in consultation with clinical experts. The benefits of the treatments were measured by considering the impact on the patient's quality of life. The costs associated with the treatments were obtained from various sources, including reports, publicly available databases, and published literature.The findings show that TARE is not only cost-saving compared to cTACE but also results in a higher number of quality-adjusted life years (QALYs) per person. While TARE was more expensive than DEE-TACE, it produced more QALYs, further indicating more favorable patient outcomes and overall treatment effectiveness. These findings could potentially impact resource allocation and decision-making for the treatment of HCC.

Dealing with Complications: First Address the Emotional Response.

Medical complications often leave the responsible physicians with strong negative emotional responses. Through self-compassion, physicians can overcome these negative emotions and continue to improve.

Prior ablation and progression of disease correlate with higher tumor-to-normal liver 99mTc-MAA uptake ratio in hepatocellular carcinoma.

PURPOSE: Factors affecting tumor-to-normal tissue ratio (T:N) have implications for patient selection, dosimetry, and outcomes when considering radioembolization for HCC. This study sought to evaluate patient, disease specific, and technical parameters that predict T:N as measured on planning pre-90Y radioembolization 99mTc-MAA scintigraphy for hepatocellular carcinoma (HCC). METHODS: 99mTc-MAA hepatic angiography procedures with SPECT/CT over a 4-year period were reviewed. Data recorded included patient demographics, details of underlying liver disease, tumor size, history of prior treatments for HCC and technical parameters from angiography. Anatomic-based segmentation was performed in 93 cases for measurement of tumor and perfused liver volumes and SPECT counts. T:N were calculated and correlated with collected variables. RESULTS: Mean calculated T:N was 2.52. History of prior ablation was significantly correlated with higher T:N (mean 3.39 vs 2.24, p = 0.003). Cases in which mapping was being performed for treatment of disease progression was significantly correlated with higher T:N (mean 3.35 vs 2.14, p = 0.001). Larger tumor size trended toward lower T:N (p = 0.052). CONCLUSION: Patients with history of ablation and those undergoing treatment for disease progression have higher T:N and, therefore, could be considered for radioembolization preferentially over alternative treatments.

Efficacy and Safety of Mechanical IVC Filtration for Preventing Pulmonary Embolism in High-Risk Orthopedic Patients Undergoing Total Hip or Knee Arthroplasty.

BACKGROUND: To determine the efficacy and safety of inferior vena cava (IVC) filters in preventing pulmonary embolism (PE) in high-risk patients undergoing hip or knee arthroplasty. METHODS: 2857 hip or knee arthroplasty procedures between January 2013 and December 2018 were retrospectively reviewed. Patients with a preoperative history of venous thromboembolism (VTE), either PE or deep venous thrombosis (DVT), were categorized as high-risk patients. The incidence of overall VTE, PE, and DVT were compared between patients with filters and those without. The subgroup analysis was also performed by patient risk, and filter status and the incidence of VTE, PE, and DVT were compared. Variables such as filter placement, history of hypercoagulability etcetra were evaluated as risk factors for the development of postoperative VTE. RESULTS: In the high-risk group, the use of IVC filters was significantly associated with a lower incidence of pulmonary embolism (0.8% vs 5.5%, P = .028). When compared with the low-risk group, the high-risk group had significantly higher incidence of PE (3.8% vs 2.0%, P = .038), DVT (11.6% vs 5.3%, P < .001), and overall VTE (15.0% vs 6.8%, P < .001). The history of VTE was associated with postoperative VTE (P < .001), PE (P = .042), and DVT (P < .001). There was no significant correlation between filter placement and postoperative VTE, DVT, or PE in the low-risk group. Filter retrieval was successful in 100% (96/96) of attempted patients with no complications. CONCLUSION: The use of IVC filters is significantly associated with a lower incidence in pulmonary embolism in high-risk arthroplasty patients. High-risk patients demonstrated an incidence of postoperative VTE over two times greater than other patients. Prophylactic placement of IVC filters in hip/knee arthroplasty is safe.

Social Media Growth at Annual Medical Society Meetings: A Comparative Analysis of Diagnostic and Interventional Radiology to Other Medical Specialties.

OBJECTIVE: To understand social media growth in both diagnostic and interventional radiology compared to other related specialties by quantifying and comparing hashtag utilization at annual medical conferences. METHODS: Official annual conference hashtags for Society of Interventional Radiology (SIR), American College of Radiology (ACR), Radiological Society of North America, American College of Cardiology, American Heart Association, and American Society of Clinical Oncology were analyzed from 2015 to 2019, along with the IR hashtag #IRad. Twitter analytics were obtained with the use of Symplur Signals, a healthcare social media analytics platform. Linear regression analysis was performed on the number of tweets and users for each hashtag. RESULTS: For annual ACR meetings, the number of tweets/user (6.96 in 2019), retweets/user (4.39 in 2019), and impressions/user (40,051 in 2019) were among the highest of all the specialties studied. This trend was observed despite a smaller number of users among ACR than most other conferences. SIR tweets increased significantly at a rate of 1032.8 tweets/year (P = 0.008) while users also significantly grew at a rate of 212.5 users/years (P = 0.007). #IRad tweets are also growing at a rate of 13,234.8 tweets/year (P = 0.026) while #IRad users are growing at a rate of 1309.5 users/year (P = 0.003). Radiological Society of North America users were significantly decreasing at -1207.1 users/year (P = 0.018). CONCLUSION: ACR consistently had one of the highest counts of tweets/user, retweets/user, and impressions/user compared to the other studied specialties, suggesting that ACR's Twitter users are more active than users outside of the field of radiology. SIR was the only studied specialty conference that had statistically significant increases in the number of tweets and users.

Increasing Volume of Bone Marrow Biopsies by Radiology Providers: Evaluation of Trends by Physician Specialty and Practice Setting.

PURPOSE: The aim of this study was to evaluate trends in bone marrow biopsies performed in the United States by physician specialty and practice setting. METHODS: The CMS Medicare Physician Supplier Procedure Summary database was queried from 2005 to 2016 for bone marrow biopsies and aspirations (BMBs). Data were categorized according to the largest subspecialty groups (medicine, surgery, radiology, pathology, and other) and encounter setting (office, inpatient hospital, and outpatient hospital). Trends in procedure volume by specialty and practice setting were evaluated. RESULTS: Between 2005 and 2016, an annual average of 11,417 BMBs were performed (range, 10,380-14,204), with no significant year-over-year change in volume. Medicine was the largest provider of BMBs by specialty, although their market share over this time period declined from 60.2% to 36.6%. Radiology saw the greatest growth in BMB market share from 4.1% to 16.2%. The compound annual growth rate (CAGR) of BMBs performed by medicine subspecialists demonstrated a decrease in year-over-year procedural volume at -5.16% (P < .001). Both surgery and radiology demonstrated positive trends in the number of BMBs performed, with CAGRs of 6.20% (P < .001) and 12.43% (P < .001), respectively. Independent of physician specialty, there was a decrease in the number of biopsies performed in the office setting, decreasing by a CAGR of -5.59% (P < .001). CONCLUSIONS: From 2005 to 2016, medicine has remained the primary provider of BMBs, although their market share has declined. Radiology has experienced the greatest rate of growth in this time period and now represents the third largest individual specialty providing this service.

A Single-Institutional Comparative Analysis of Advanced Versus Standard Snare Removal of Inferior Vena Cava Filters.

PURPOSE: To investigate differences in procedure time, radiation exposure, and periprocedural complications associated with advanced inferior vena cava (IVC) filter retrieval compared with standard snare retrieval. MATERIALS AND METHODS: A total of 378 patients underwent standard or advanced IVC filter retrieval over a 5-year period. Technical success, retrieval techniques, fluoroscopy time, radiation dose, and complications were analyzed. All retrieval procedures with techniques other than a "snare-and-sheath" method were categorized as advanced, including failed standard attempts requiring intraprocedural conversion to advanced techniques. RESULTS: A total of 462 filter retrieval attempts were made in 378 patients (57% female). Success rates for standard and advanced retrieval attempts were 86.8% (317 of 365) and 91.8% (89 of 97), respectively. The rate of periprocedural complications was significantly higher in the advanced retrieval group (P = .006). Complication rates for standard and advanced retrievals were 0.6% (2 of 318; all minor) and 5.2% (5 of 97; 3 minor [3.1%] and 2 major [2.1%]), respectively. The 2 major complications during advanced retrievals included filter fracture and embolization. Average fluoroscopy time for advanced retrievals was significantly higher than for standard retrievals (23.1 min vs 4.3 min; P < .001). Average radiation dose for advanced retrievals was also significantly higher than for standard retrievals (557.2 mGy vs 156.9 mGy; P < .001). Use of general anesthesia was also significantly more common in advanced retrievals compared with standard retrievals (6.2% vs 0.9%; P = .002). CONCLUSIONS: Advanced filter retrieval results in a similarly high rate of technical success compared with standard snare retrieval but is associated with greater fluoroscopy time, anesthesia requirements, and radiation exposure.

Value of follow-up angiography: additional interventions in patients undergoing catheter-directed thrombolysis for massive and submassive pulmonary embolism.

PURPOSE: Catheter-directed thrombolysis (CDT) is an emerging, minimally invasive treatment for patients with massive and submassive pulmonary embolism (PE). The value of follow-up pulmonary angiography for evaluating improvement after CDT is limited by a paucity of large studies assessing its utility and role for additional intervention. The purpose of our study was to assess the role of next-day pulmonary angiography for CDT in patients with acute massive and submassive PE undergoing continuous pulmonary arterial pressure monitoring, and secondarily, determine factors that are correlated with a need for further therapy. METHODS: Patients who underwent CDT from 2006 to 2016 for massive and submassive PE were reviewed. Patient demographics, comorbidities, preprocedural lab results, noninvasive hemodynamic studies, and technical variables were recorded. Among patients receiving next-day angiography, those requiring further therapy, defined as continued CDT beyond the standard 24 hours (with or without catheter repositioning or exchange) and/or mechanical or suction thrombectomy were contrasted with those not requiring additional therapy to assess for the role of angiography and patient factors that correlate with need for further therapy. RESULTS: Thirty-two patients underwent CDT for massive (n=14) and submassive (n=18) PE. Eighteen (56.3%) were male, 14 (43.7%) were Caucasian, 18 (56.3%) were African-American, with a mean age of 66.2 years (range, 26-87 years). Of the 27 (84.4%) patients that underwent next-day pulmonary angiography, 16 (59.3%) did not require additional therapy and 11 (40.7%) did require additional therapy. Additional therapy included extended CDT beyond 24 hours (n=4), mechanical/suction thrombectomy (n=5), or both extended CDT and mechanical/suction thrombectomy (n=2). Younger age (50.1 vs. 62.2 years, P = 0.039) was correlated with a need for further therapy. Initial (40.7 vs. 34.8 mmHg, P = 0.248), next-day (31.5 vs. 26.3 mmHg, P = 0.259), and interval change (4.6 vs. 8.0 mmHg, P = 0.669) in pulmonary artery pressures were not statistically significant between patient subsets. Preprocedural right ventricular/left ventricular ratio (RV/LV) also did not differ significantly (1.74 vs. 1.75, P = 0.961). Thirty-day mortality was comparable (2 vs. 1, P = 0.332). CONCLUSION: Next-day pulmonary angiography is a useful method to identify patients needing additional therapy including extended CDT and/or mechanical or suction thrombectomy in acute PE management. Pulmonary arterial pressures and preprocedural RV/LV ratios were not found to be predicative of those requiring further intervention.

Inability of conventional imaging findings to predict response to laparoscopic release of the median arcuate ligament in patients with celiac artery compression.

OBJECTIVE: The objective of this study was to identify duplex ultrasound (DUS) or computed tomography angiography (CTA) imaging findings that can predict clinical response to laparoscopic release of the median arcuate ligament (MAL) in patients with celiac artery compression. METHODS: There were 299 patients who were evaluated for MAL syndrome (MALS) between January 2009 and November 2015. Of these, 29 underwent laparoscopic MAL release and completed 1-year follow-up. The patients' preoperative and postoperative symptoms, use of analgesics, and body mass index were recorded. Patients' demographics and DUS and CTA findings were reviewed. Fisher exact and Student t-tests were used to identify correlation between patient or imaging variables and clinical outcomes. RESULTS: There were 19 patients (66%) who reported improvement in symptoms, and 18 (62%) decreased their use of analgesics; average body mass index increased by 0.2 (standard deviation, 1.97; range, -3.35 to 5.11). No celiac artery DUS finding (peak celiac artery velocity, angle of deflection, or change in preoperative to postoperative velocity) was predictive of successful clinical outcomes (P > .05). Similarly, no CTA finding (characteristic morphology, cross-sectional area, diameter, or location of the focal stenosis of the celiac artery) was associated with clinical outcomes (P > .05). CONCLUSIONS: Clinical response to laparoscopic MAL release was favorable in two-thirds of patients; however, no specific imaging finding of stenosis was predictive of this response. Given that the severity of stenosis on conventional imaging had no impact on treatment efficacy, vascular compromise may not be the primary cause of pain in patients presenting with this syndrome. Future investigation incorporating the neurogenic basis of MALS pain, such as with diagnostic celiac ganglion blockade, would be helpful in further elucidating the enigmatic pathophysiologic process of MALS.

Percutaneous Vertebral Augmentation for Vertebral Compression Fractures: National Trends in the Medicare Population (2005-2015).

STUDY DESIGN: Retrospective analysis of Medicare data OBJECTIVE.: To analyze trends of vertebral augmentation in the elderly Medicare population in the context of evolving evidence and varied medical society opinions. SUMMARY OF BACKGROUND DATA: Percutaneous vertebral augmentation offers a minimally invasive therapy for vertebral compression fractures. Numerous trials have been published on this topic with mixed results. The impact of these studies and societal recommendations on physician practice patterns is not well understood. METHODS: The Centers for Medicare and Medicaid Services annual Medicare Physician Supplier Procedure Summary database was examined for kyphoplasty and vertebroplasty procedures from 2005 through 2015. Top provider specialties were determined based on annual procedural volume, and grouped into the three broad categories of radiology, surgery, and anesthesia/pain medicine. Data entries were independently analyzed by provider type, site of service, submitted charges, and reimbursement rates for interventions during the study period. RESULTS: Between 2005 and 2015 total annual claims for vertebral augmentation procedures in the Medicare population increased from 108.11% (37,133-77,276) peaking in 2008 and declining by 15.56% in 2009. Radiology is the largest provider of vertebral augmentation by specialty with declining market shares from 71% in 2005 to 43% in 2015. The frequency of vertebroplasty declined by 61.7% (35,409-13,478) from 2005 to 2015 with reduction in Medicare reimbursement. Annual volume of kyphoplasty grew by 18.3% (48,725-57,646) with significant increase in reimbursement for office-based procedures ($728.50/yr, P < 0.001, R = 0.69). CONCLUSION: The annual volume of vertebral augmentation declined in 2009 following two negative trials on vertebroplasty. Although these publications had a persistent negative impact on practice of vertebroplasty, the overall frequency of vertebral augmentation in the Medicare population has not changed significantly between 2005 and 2015. Instead, there has been a significant shift in provider practice patterns in favor of kyphoplasty in increasingly outpatient and office-based settings. LEVEL OF EVIDENCE: 3.

Rising Retrieval Rates of Inferior Vena Cava Filters in the United States: Insights From the 2012 to 2016 Summary Medicare Claims Data.

BACKGROUND: To determine recent inferior vena cava filter (IVCF) retrieval volumes and rates in the Medicare population. METHODS: The summary Medicare claims data were searched for the years 2012 to 2016 to identify the frequency of IVCF placements and retrievals. The new Healthcare Common Procedure Coding System code for filter retrieval introduced in 2012, 37193, was used to track filter retrievals. Trends in number of IVCF placements and retrievals over the study period were evaluated, both of which were further stratified by physician specialty and site of service. Aggregate and compound annual growth rates for retrievals were also computed. RESULTS: A total of 255,034 filters were placed over the study period, with the filter placement volume declining from 61,889 in 2012 to 38,095 in 2016. Filter retrievals, however, increased from 4,327 in 2012 to 8,405 in 2016. The net filter retrieval rate per annual filters placed increased from 6.9% in 2012 to 22.1% in 2016, yielding an average filter retrieval rate and compound annual growth rate of 11.6% and 18.1% respectively. Radiologists placed and retrieved the majority of filters (60.4% placed, 63.5% retrieved) compared with nonradiologists. The inpatient setting was the dominant site for filter placement compared with the outpatient setting for filter retrieval across all years and specialties. CONCLUSIONS: Since introduction of the unique Healthcare Common Procedure Coding System code for IVCF retrieval in 2012, IVCF placements in the Medicare population have been declining and net retrieval rates have risen. Radiologists continue to place and retrieve the majority of filters.

Hemodialysis Access Maintenance in the Medicare Population: An Analysis Over a Decade of Trends by Provider Specialty and Site of Service.

PURPOSE: To evaluate annual national trends in hemodialysis access maintenance procedures in the Medicare population by specialty and setting. METHODS: Medicare Physician Supplier Procedure Summary Master Files between 2005 and 2015 were analyzed for procedure codes of hemodialysis access angiography and percutaneous thrombectomy. Using physician specialty codes, component procedure volume for endovascular services were queried for radiology, medicine, and surgery. Data entries were analyzed by provider specialty and place of service. Average submitted and allowed charges per intervention were extracted. Linear regression modeling was used to identify trends in number of and allowed charges by specialty and practice setting. RESULTS: Between 2005 and 2015, the frequency of dialysis access angiography for Medicare fee-for-service beneficiaries increased by a total of 74.71% (211,181 to 368,955). Specialty-specific analysis demonstrated volume increases of 220.21% (22,128 to 101,109) for surgery, 249.02% (32,690 to 114,094) for medicine, and 2.81% (135,564 to 139, 367) for radiology. By 2015, an increased trend from hospital-based to non-hospital-based procedures associated with significantly higher reimbursement rates to providers (+18,798 non-hospital-based cases/year, $46.95/year, P ≤ .001) was also observed, with medicine performing the highest volume of non-hospital-based procedures. In this period, there was also a modest total overall increase of percutaneous thrombectomy procedures by 7.75% (61,485 to 66,250). CONCLUSIONS: The frequency of endovascular hemodialysis access maintenance procedures in the Medicare fee-for-service program has increased from 2005 to 2015, with the majority market share transitioning from radiologists to non-radiologists. Similarly, most access maintenance in this time period changed from hospital-based to non-hospital-based interventions.