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1.
Radiology ; 309(3): e230555, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38085076

ABSTRACT

Background Benign prostatic hyperplasia (BPH) is a disease that affects millions of U.S. men and is costly to treat. Purpose To compare the cost-effectiveness of four minimally invasive therapies (MITs) and medical management for the treatment of BPH. Materials and Methods A cost-effectiveness analysis from a payer's perspective with Markov modeling was performed, comparing prostatic artery embolization (PAE), prostatic urethral lift, aquablation, water vapor thermal therapy, and medical management for BPH spanning a time horizon of 5 years. The model incorporated the probability of procedural complications and recurrent symptoms necessitating retreatment, which were extracted from published studies with long-term follow-up. Costs were based on Medicare reimbursements using CPT codes for ambulatory surgery centers. Outcomes were measured using the quality-adjusted life year (QALY), incorporating both life quality and expectancy. Statistical analyses included a base case calculation (using the most probable value of each parameter) and probabilistic and deterministic sensitivity analyses. Results In the base case calculation, outcomes for the strategies were comparable, with a difference of 0.030 QALY (11 days of life in perfect health) between the most (PAE) and least (medical management) effective strategies. PAE was the most cost-effective strategy relative to medical management, with an incremental cost-effectiveness ratio of $64 842 per QALY. Probabilistic sensitivity analysis showed PAE was more cost-effective compared with prostatic urethral lift, aquablation, water vapor therapy, and medical management in pairwise comparisons. In sensitivity analysis of retreatment risk, PAE remained the most cost-effective strategy until its repeat treatment rates exceeded 2.30% per 6 months, at which point water vapor therapy became the optimal choice. PAE was the most cost-effective procedure when its procedural cost was lower than $4755. Aquablation and prostatic urethral lift became more cost-effective when their procedural costs were lower than $3015 and $1097, respectively. Conclusion This modeling-based study showed that PAE appears to be a cost-effective modality among medical management and MITs for patients with BPH, with comparable outcomes to prostatic urethral lift, water vapor therapy, and aquablation at a lower expected cost. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.


Subject(s)
Embolization, Therapeutic , Lower Urinary Tract Symptoms , Prostatic Hyperplasia , Transurethral Resection of Prostate , United States , Male , Humans , Aged , Prostate/surgery , Prostatic Hyperplasia/surgery , Prostatic Hyperplasia/complications , Cost-Effectiveness Analysis , Transurethral Resection of Prostate/adverse effects , Transurethral Resection of Prostate/methods , Embolization, Therapeutic/methods , Steam , Medicare , Minimally Invasive Surgical Procedures , Treatment Outcome , Lower Urinary Tract Symptoms/etiology
2.
J Vasc Interv Radiol ; 33(12): 1605-1615, 2022 12.
Article in English | MEDLINE | ID: mdl-35964881

ABSTRACT

PURPOSE: To compare the cost effectiveness of prostatic artery embolization (PAE) with that of transurethral resection of the prostate (TURP) for the treatment of medically refractory benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A cost-effectiveness analysis with Markov modeling was performed, comparing the clinical course after PAE with that after TURP for 3 years. Probabilities were obtained from the available literature, and costs were based on Medicare reimbursements and published cost analyses. Outcomes were measured using quality-adjusted life-year (QALY). Statistical analyses included base case calculation, probabilistic sensitivity analysis, and deterministic sensitivity analysis to assess the robustness of the conclusion under different clinical scenarios. RESULTS: Base case calculation showed comparable outcomes (PAE, 2.845 QALY; TURP, 2.854 QALY), with a cost difference of $3,104 (PAE, $2,934; TURP, $6,038). The incremental cost-effectiveness ratio was $360,249/QALY. PAE was dominant in 23.2% and more cost effective in 48.4% of the probabilistic sensitivity analysis simulations. PAE was better if its recurrence risk was <20.4% per year and even when the TURP recurrence risk was assumed to be 0%. TURP would be more cost effective when its procedural cost was <$3,367 or the PAE procedural cost >$4,409. PAE remained cost effective when varying the risks and costs of the minor and major short-term or long-term adverse events of both procedures. TURP would be the better strategy if the utility of BPH recurrence was <0.85 QALY. CONCLUSIONS: PAE is a cost-effective strategy to treat medically refractory BPH, resulting in comparable health benefits at a lower cost than that of TURP even when accounting for extreme alterations in adverse events, costs, and recurrence rates.


Subject(s)
Embolization, Therapeutic , Prostatic Hyperplasia , Transurethral Resection of Prostate , Aged , United States , Male , Humans , Prostatic Hyperplasia/diagnostic imaging , Prostatic Hyperplasia/therapy , Transurethral Resection of Prostate/adverse effects , Cost-Benefit Analysis , Prostate/blood supply , Embolization, Therapeutic/methods , Treatment Outcome , Medicare , Arteries
3.
CVIR Endovasc ; 5(1): 11, 2022 Feb 08.
Article in English | MEDLINE | ID: mdl-35133515

ABSTRACT

BACKGROUND: Aneurysms are rare anomalies of the portomesenteric venous system. Thrombotic complications of these lesions can lead to mesenteric venous ischemia and bowel infarction, potentially requiring surgical intervention. Herein we describe a case of mesenteric ischemia due to a large thrombosed portomesenteric aneurysm treated with endovascular techniques. CASE PRESENTATION: A 37-year-old previously healthy male who presented with abdominal pain to his local emergency department was found to have a thrombosed 12.0 × 5.1 cm portomesenteric venous aneurysm with evidence of mesenteric ischemia on CT. When conservative management with anticoagulation failed, transhepatic pharmacomechanical thrombolysis was initially performed. This was followed by TIPS placement with additional trans-TIPS thrombectomy to improve sluggish portal outflow and prevent re-thrombosis. The patient's symptoms and imaging findings of ischemia resolved after endovascular therapy. No surgical intervention was required, and the patient was discharged on enoxaparin before being transitioned to apixaban. The TIPS remained patent at 2-year follow-up, with no change in the size of the aneurysm or re-thrombosis noted. The patient's synthetic liver function was preserved with no evidence of hepatic encephalopathy during the follow-up period. CONCLUSIONS: Endovascular therapies may be used to manage thrombotic complications of portomesenteric venous aneurysms, obviating the need for surgical intervention in selected patients.

4.
Article in English | MEDLINE | ID: mdl-33796444

ABSTRACT

Central venous stenosis in hemodialysis patients rarely causes venous hypertension and intracranial hemorrhage. A 54 year-old male with right arm arteriovenous fistula was transferred to our institution in a comatose state following right parietal venous infarction. Fistulography showed right brachiocephalic vein (BCV) occlusion with reflux into the right transverse sinus and obstruction of left internal jugular vein outflow due to the styloid process. Balloon venoplasty of the right BCV occlusion failed to improve the patient's status because of the delayed diagnosis. Headaches and neurologic symptoms in hemodialysis patients can herald intracranial hypertension due to central venous occlusion and needs prompt assessment with fistulography.

7.
J Vasc Interv Radiol ; 31(8): 1242-1248, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32522505

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the effectiveness and adverse outcomes of percutaneous cryoablation (CA) for treatment of renal masses in a large cohort of patients. MATERIALS AND METHODS: This retrospective analysis included 299 CA procedures (297 masses in 277 patients) performed between July 2007 and May 2018 at a single institution. The mean patient age was 66.1 years (range, 30-93 years) with 65.8% being male. A total of 234 (78.8%) masses were biopsy-proven renal cell carcinoma (RCC). The mean maximal tumor diameter was 2.5 cm (range, 0.7-6.6 cm). Efficacy was assessed only for ablations of biopsy-proven RCC, whereas the evaluation of adverse events and renal function included all masses. Complications were graded according to the Society of International Radiology classification. RESULTS: Major complications occurred in 3.0% of procedures (n = 9), none of which resulted in death or permanent disability. The mean imaging follow-up period was 27.4 months (range, 1-115) for the 199 RCC patients (204 ablated tumors) with follow-up imaging available. Complete response on initial follow-up imaging at mean 4.2 months (range, 0.3-75.6) was achieved in 195 of 204 tumors (95.6%) after a single session and in 200 of 204 tumors (98.0%) after 1 or 2 sessions. Of the RCC patients achieving complete response initially, local recurrence during the follow-up period occurred in 3 of 200 tumors (1.5%). Metastatic progression occurred in 10 of 193 (5.2%) RCC patients without prior metastatic disease during follow-up. CONCLUSIONS: CA for renal masses is safe and remains efficacious through intermediate- and long-term follow-up.


Subject(s)
Carcinoma, Renal Cell/surgery , Cryosurgery , Kidney Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Biopsy , Carcinoma, Renal Cell/secondary , Cryosurgery/adverse effects , Disease Progression , Female , Humans , Kidney Neoplasms/pathology , Male , Middle Aged , Neoplasm Recurrence, Local , Postoperative Complications/etiology , Retrospective Studies , Risk Assessment , Risk Factors , Time Factors , Treatment Outcome , Tumor Burden
8.
J Hepatocell Carcinoma ; 6: 93-103, 2019.
Article in English | MEDLINE | ID: mdl-31355158

ABSTRACT

Purpose: To determine whether chemoembolization using drug-eluting beads (DEB-TACE) is safe and effective for liver transplantation candidates with liver-limited hepatocellular carcinoma (HCC) without vascular invasion and baseline hepatic dysfunction. Materials and methods: Seventeen adult liver transplantation candidates (median age 66 years, range 58-73 years; 13 men) with HCC were treated with DEB-TACE as a part of Stage 1 of a prospective single-institution Phase II trial. All patients had marginal hepatic reserve based on at least one of the following criteria: ascites (n=14), bilirubin between 3 and 6 mg/dL (n=5), AST 5-10 times upper normal limit (n=1), INR between 1.6 and 2.5 (n=4), portal vein thrombosis (n=2), and/or portosystemic shunt (n=2). Primary study objectives were safety and best observed radiographic response. Results: Thirty-seven DEB-TACE procedures were performed. Objective response rate and disease control rate were 63% and 88%, respectively. HCC progression was observed in 12 patients. Median time to progression was 5.6 months (range 0.9-13.6 months). Within 1 month following DEB-TACE, 13 patients (76%) developed grade 3 or 4 AE attributable to the procedure. Four patients (all within Milan Criteria) were transplanted (2.7-6.9 months after DEB-TACE), and 12 patients died (1.8-32 months after DEB-TACE). All deaths were due to liver failure that was either unrelated to HCC (n=5), in the setting of metastatic HCC (n=5), or in the setting of locally advanced HCC (n=2). Mortality rate at 1 month was 0%. Conclusions: DEB-TACE achieves tumor responses but carries a high risk of hepatotoxicity for liver transplant candidates with HCC and marginal hepatic reserve.

9.
J Vasc Interv Radiol ; 30(6): 918-921, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30982638

ABSTRACT

PURPOSE: To determine the clinical outcomes of patients who underwent image-guided drainage of peripancreatic fluid collections after simultaneous pancreas-kidney (SPK) transplantation. MATERIALS AND METHODS: A retrospective review of all patients who underwent peripancreatic fluid collection drainage after SPK, from January 2000 to August 2017, at a single institution was performed. Patient characteristics, surgical technique, medication regimen, microbial analysis, and clinical outcomes were reviewed. Thirty-one patients requiring a total of 41 drainages were included in this study. The median age was 44 years (range 30-58 years), and median time between SPK and drainage was 28 days (range 8 to 3,401 days). Fisher's exact test, unpaired Student t-tests, and Pearson correlations were used for statistical analysis. RESULTS: Fever (51%) and abdominal pain (31%) were the most common presenting symptoms. The average amount of fluid drained at the time of drain placement was 97 mL (SD 240 mL). The average time spent with a drain in place was 33 days (SD 31 days). Microorganisms were isolated in the fluid of 22 of 41 drainages (54%), with mixed gastrointestinal flora being the most common. No further intervention was needed in 34 of 41 drainages (82%). However, drainage failed in 5 of 31 patients (16%), requiring surgical intervention with removal of the pancreas transplant. CONCLUSIONS: Percutaneous drainage of peripancreatic fluid collections after SPK transplantation is a safe and effective treatment option.


Subject(s)
Drainage/methods , Kidney Transplantation/adverse effects , Pancreas Transplantation/adverse effects , Postoperative Complications/therapy , Adult , Drainage/adverse effects , Drainage/instrumentation , Female , Humans , Male , Middle Aged , Postoperative Complications/diagnostic imaging , Postoperative Complications/etiology , Retrospective Studies , Risk Factors , Time Factors , Treatment Outcome
10.
J Vasc Interv Radiol ; 30(4): 589-593.e3, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30910181

ABSTRACT

Opportunities for interventional radiology (IR) education and exposure remain limited at medical institutions without a local IR presence, thereby excluding a medical student population with potential to pursue careers in IR or become referring providers to IR. The purpose of this study was to evaluate the efficacy of a Webinar-based IR elective as an educational tool for outreach to US medical schools lacking local preclinical IR exposure. Our early results indicate that a Webinar-based IR lecture series can serve as an effective method for educating future physicians about the field of IR and when to consult IR for patient management.


Subject(s)
Career Choice , Computer-Assisted Instruction/methods , Education, Medical, Undergraduate/methods , Internet , Radiologists/education , Radiology, Interventional/education , Specialization , Students, Medical , Curriculum , Female , Humans , Male
11.
J Vasc Interv Radiol ; 30(7): 1043-1047, 2019 Jul.
Article in English | MEDLINE | ID: mdl-30772167

ABSTRACT

PURPOSE: To evaluate efficacy and safety of transjugular liver biopsy (TJLB) via the left hepatic vein in patients with left lobe-only liver transplants (LLOTs). MATERIALS AND METHODS: Retrospective review revealed 43 TJLBs performed in 26 patients with LLOTs (mean age 51.3 y; range, 18-73 y) between January 2009 and June 2016 at a single institution. A comparison group of 44 randomly selected TJLBs performed in 37 orthotopic whole liver transplant (OWLT) recipients (mean age 57.6 y; range, 35-74 y) during the same time period was evaluated. Patient demographics, type and age of transplant, technical success, adequacy of samples, number of portal tracts obtained, pathologic diagnosis, and complication rate were reviewed. RESULTS: Technical success was achieved in 98% (42/43) of LLOT procedures. TJLB failed in 1 patient with LLOT, in whom no patent hepatic veins were identified. Technical success was achieved in 100% (44/44) in the OWLT group. Mean (SD) number of needle passes was 4.12 (1.25) in the LLOT group vs 3.95 (1.28) in the OWLT group (P = .54). Mean (SD) specimen length was 1.16 (0.75) cm in the LLOT group vs 1.19 (0.58) cm in the OWLT group (P = .78). Mean (SD) number of portal tracts obtained in the LLOT group was 10.7 (5.26) vs 12.3 (4.68) in the OWLT group (P = .17). No major complications were observed in either group. CONCLUSIONS: TJLB in adult patients with LLOTs appears safe and feasible, with favorable rates of technical success and adequacy of sampling.


Subject(s)
Biopsy, Needle/methods , Catheterization, Central Venous/methods , Hepatic Veins , Image-Guided Biopsy/methods , Jugular Veins , Liver Transplantation , Postoperative Complications/pathology , Adolescent , Adult , Aged , Angiography, Digital Subtraction , Biopsy, Needle/adverse effects , Catheterization, Central Venous/adverse effects , Female , Hepatic Veins/diagnostic imaging , Humans , Image-Guided Biopsy/adverse effects , Jugular Veins/diagnostic imaging , Liver Transplantation/adverse effects , Male , Middle Aged , Phlebography , Postoperative Complications/etiology , Predictive Value of Tests , Radiography, Interventional , Retrospective Studies , Risk Assessment , Risk Factors , Young Adult
12.
J Vasc Interv Radiol ; 29(9): 1248-1253, 2018 09.
Article in English | MEDLINE | ID: mdl-30061059

ABSTRACT

PURPOSE: To assess the effectiveness of disposable radiation-absorbing surgical drapes on operator radiation dose during transjugular liver biopsy (TJLB). MATERIALS AND METHODS: This dual-arm prospective, randomized study was conducted between May 2017 and January 2018 at a single institution. TJLB procedures (N = 62; patient age range, 19-80 y) were assigned at a 1:1 ratio to the use of radiation-absorbing surgical drapes or standard surgical draping. The primary outcome was cumulative radiation equivalent dose incident on the operator, as determined by an electronic personal dosimeter worn at the chest during each procedure. Cumulative kerma-area product (KAP), total fluoroscopy time, and total number of exposures used during each liver biopsy procedure were also determined. RESULTS: Mean radiation dose incident on the operator decreased by 56% with the use of radiation-absorbing drapes (37 µSv ± 35; range, 4-183 µSv) compared with standard draping (84 µSv ± 58; range, 11-220 µSv). Radiation incident on the patient was similar between groups, with no significant differences in mean KAP, total fluoroscopy time, and number of exposures acquired during the procedures. CONCLUSIONS: Use of disposable radiation-absorbing drapes reduces scatter radiation to interventionalists performing TJLB.


Subject(s)
Image-Guided Biopsy/instrumentation , Liver Diseases/diagnostic imaging , Occupational Exposure/prevention & control , Occupational Health , Radiation Exposure/prevention & control , Radiation Protection/instrumentation , Radiography, Interventional/instrumentation , Radiologists , Surgical Drapes , Adult , Aged , Aged, 80 and over , Disposable Equipment , Female , Humans , Image-Guided Biopsy/adverse effects , Liver Diseases/pathology , Male , Middle Aged , Occupational Exposure/adverse effects , Pilot Projects , Prospective Studies , Protective Factors , Radiation Dosage , Radiation Dosimeters , Radiation Exposure/adverse effects , Radiography, Interventional/adverse effects , Risk Factors , San Francisco , Scattering, Radiation , Young Adult
13.
J Vasc Interv Radiol ; 28(8): 1129-1135.e1, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28457758

ABSTRACT

PURPOSE: To assess radiation dose reduction during uterine fibroid embolization (UFE) using an optimized angiographic processing and acquisition platform. MATERIALS AND METHODS: Radiation dose data for 70 women (mean age, 46 y; range, 34-67 y) who underwent UFE were retrospectively analyzed. Twenty-one patients underwent UFE using the baseline fluoroscopic and angiographic image acquisition platform, and 49 underwent UFE after implementing an optimized imaging platform in otherwise identical angiography suites. Cumulative kerma-area product (CKAP), cumulative air kerma (CAK), total fluoroscopy time, and image exposure number were collected for each procedure. Image quality was assessed by 3 interventional radiologists blinded to the platform used for image acquisition and processing. RESULTS: Patients undergoing UFE using the new x-ray fluoroscopy platform had significantly lower CKAP and CAK indicators than patients for whom baseline settings were used. Mean CKAP decreased by 60% from 438.5 Gy · cm2 (range, 180.3-1,081.1 Gy · cm2) to 175.2 Gy · cm2 (range, 47.1-757.0 Gy · cm2; P < .0001). Mean CAK decreased by 45% from 2,034.2 mGy (range, 699.3-5,056.0 mGy) to 1,109.8 mGy (range, 256.6-4,513.6 mGy; P = .001). No degradation of image quality was identified through qualitative evaluation. CONCLUSIONS: Significant reduction in patient radiation dose indicators can be achieved with use of an optimized image acquisition and processing platform.


Subject(s)
Embolization, Therapeutic/methods , Leiomyoma/diagnostic imaging , Leiomyoma/therapy , Radiation Protection/methods , Radiography, Interventional , Uterine Neoplasms/diagnostic imaging , Uterine Neoplasms/therapy , Adult , Aged , Angiography, Digital Subtraction , Female , Fluoroscopy , Humans , Middle Aged , Radiation Dosage , Retrospective Studies , Tomography, X-Ray Computed , Treatment Outcome
14.
Cardiovasc Diagn Ther ; 6(6): 599-611, 2016 Dec.
Article in English | MEDLINE | ID: mdl-28123980

ABSTRACT

Venous thromboembolism (VTE) is an extremely common form of vascular disease and impacts a great number of patients worldwide. Acute deep vein thrombosis (DVT) is a subset of VTE and is traditionally been treated with anticoagulation. There is good quality data which suggests the use of catheter directed interventions for the treatment of acute DVT with the aim of reducing post-thrombotic syndrome (PTS). The present review will discuss the various therapies available for acute DVT, focusing on catheter directed interventions, ranging from traditional anticoagulation to the most novel forms of aspiration thrombectomy.

15.
J Vasc Interv Radiol ; 26(9): 1331-8, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26212556

ABSTRACT

PURPOSE: To evaluate radiation dose reduction in patients undergoing transarterial chemoembolization with the use of a new image acquisition and processing platform. MATERIALS AND METHODS: Radiation-dose data were obtained from 176 consecutive chemoembolization procedures in 135 patients performed in a single angiography suite. From January 2013 through October 2013, 85 procedures were performed by using our institution's standard fluoroscopic settings. After upgrading the x-ray fluoroscopy system with an image acquisition and processing platform designed to reduce image noise and reduce skin entrance dose, 91 chemoembolization procedures were performed from November 2013 through December 2014. Cumulative dose-area product (CDAP), cumulative air kerma (CAK), and total fluoroscopy time were recorded for each procedure. Image quality was assessed by three interventional radiologists blinded to the x-ray acquisition platform used. RESULTS: Patient radiation dose indicators were significantly lower for chemoembolization procedures performed with the novel imaging platform. Mean CDAP decreased from 3,033.2 dGy·cm(2) (range, 600.3-9,404.1 dGy·cm(2)) to 1,640.1 dGy·cm(2) (range, 278.6-6,779.9 dGy·cm(2); 45.9% reduction; P < .00001). Mean CAK decreased from 1,445.4 mGy (range, 303.6-5,233.7 mGy) to 971.7 mGy (range, 144.2-3,512.0 mGy; 32.8% reduction; P < .0001). A 20.3% increase in mean total fluoroscopy time was noted after upgrading the imaging platform, but blinded analysis of the image quality revealed no significant degradation. CONCLUSIONS: Although a small increase in fluoroscopy time was observed, a significant reduction in patient radiation dose was achieved by using the optimized imaging platform, without image quality degradation.


Subject(s)
Angiography/instrumentation , Chemoembolization, Therapeutic/instrumentation , Fluoroscopy/instrumentation , Radiation Dosage , Radiation Protection/instrumentation , Radiography, Interventional/instrumentation , Adult , Aged , Aged, 80 and over , Equipment Design , Equipment Failure Analysis , Female , Humans , Male , Middle Aged , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Young Adult
16.
AJR Am J Roentgenol ; 197(4): W706-12, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21940543

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate automated CT volumetry in the assessment of living-donor livers for transplant and to compare this technique with software-aided interactive volumetry and manual volumetry. MATERIALS AND METHODS: Hepatic CT scans of 18 consecutively registered prospective liver donors were obtained under a liver transplant protocol. Automated liver volumetry was developed on the basis of 3D active-contour segmentation. To establish reference standard liver volumes, a radiologist manually traced the contour of the liver on each CT slice. We compared the results obtained with automated and interactive volumetry with those obtained with the reference standard for this study, manual volumetry. RESULTS: The average interactive liver volume was 1553 ± 343 cm(3), and the average automated liver volume was 1520 ± 378 cm(3). The average manual volume was 1486 ± 343 cm(3). Both interactive and automated volumetric results had excellent agreement with manual volumetric results (intraclass correlation coefficients, 0.96 and 0.94). The average user time for automated volumetry was 0.57 ± 0.06 min/case, whereas those for interactive and manual volumetry were 27.3 ± 4.6 and 39.4 ± 5.5 min/case, the difference being statistically significant (p < 0.05). CONCLUSION: Both interactive and automated volumetry are accurate for measuring liver volume with CT, but automated volumetry is substantially more efficient.


Subject(s)
Liver Transplantation , Liver/anatomy & histology , Liver/diagnostic imaging , Living Donors , Tomography, X-Ray Computed/methods , Adult , Automation , Contrast Media/administration & dosage , Female , Humans , Imaging, Three-Dimensional , Iohexol/administration & dosage , Male , Middle Aged , Organ Size , Radiographic Image Interpretation, Computer-Assisted , Retrospective Studies , Software
17.
Med Phys ; 37(5): 2159-66, 2010 May.
Article in English | MEDLINE | ID: mdl-20527550

ABSTRACT

PURPOSE: Computerized liver extraction from hepatic CT images is challenging because the liver often abuts other organs of a similar density. The purpose of this study was to develop a computer-aided measurement of liver volumes in hepatic CT. METHODS: The authors developed a computerized liver extraction scheme based on geodesic active contour segmentation coupled with level-set contour evolution. First, an anisotropic diffusion filter was applied to portal-venous-phase CT images for noise reduction while preserving the liver structure, followed by a scale-specific gradient magnitude filter to enhance the liver boundaries. Then, a nonlinear grayscale converter enhanced the contrast of the liver parenchyma. By using the liver-parenchyma-enhanced image as a speed function, a fast-marching level-set algorithm generated an initial contour that roughly estimated the liver shape. A geodesic active contour segmentation algorithm coupled with level-set contour evolution refined the initial contour to define the liver boundaries more precisely. The liver volume was then calculated using these refined boundaries. Hepatic CT scans of 15 prospective liver donors were obtained under a liver transplant protocol with a multidetector CT system. The liver volumes extracted by the computerized scheme were compared to those traced manually by a radiologist, used as "gold standard." RESULTS: The mean liver volume obtained with our scheme was 1504 cc, whereas the mean gold standard manual volume was 1457 cc, resulting in a mean absolute difference of 105 cc (7.2%). The computer-estimated liver volumetrics agreed excellently with the gold-standard manual volumetrics (intraclass correlation coefficient was 0.95) with no statistically significant difference (F = 0.77; p(F < or = f) = 0.32). The average accuracy, sensitivity, specificity, and percent volume error were 98.4%, 91.1%, 99.1%, and 7.2%, respectively. Computerized CT liver volumetry would require substantially less completion time (compared to an average of 39 min per case by manual segmentation). CONCLUSIONS: The computerized liver extraction scheme provides an efficient and accurate way of measuring liver volumes in CT.


Subject(s)
Algorithms , Image Processing, Computer-Assisted/methods , Liver/anatomy & histology , Liver/diagnostic imaging , Tomography, X-Ray Computed/methods , Humans , Image Processing, Computer-Assisted/standards , Organ Size , Reference Standards
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