ABSTRACT
Background: Current evidence indicates that erectile dysfunction (ED) is an independent risk factor for future cardiovascular events. This study aimed to estimate the cost-effectiveness of screening and subsequent preventive treatment for cardiovascular risk factors among men newly diagnosed with ED from the Swiss healthcare system perspective. Methods: Based on known data on ED and cardiovascular disease (CVD) prevalence and incidence costs and effects of a screening intervention for cardiovascular risk including corresponding cardiovascular prevention in men with ED were calculated for the Swiss population over a period of 10 years. Results: Screening and cardiovascular prevention over a period of 10 years in Swiss men with ED of all seriousness degrees, moderate and severe ED only, or severe ED only can probably avoid 41,564, 35,627, or 21,206 acute CVD events, respectively. Number needed to screen (NNS) to prevent one acute CVD event is 30, 23, and 10, respectively. Costs for the screening intervention are expected to be covered at the seventh, the fifth, and the first year, respectively. Conclusion: Screening and intervention for cardiovascular risk factors in men suffering from ED is a cost-effective tool not only to strengthen prevention and early detection of cardiovascular diseases but also to avoid future cardiovascular events.
Subject(s)
Cardiovascular Diseases , Erectile Dysfunction , Male , Humans , Erectile Dysfunction/diagnosis , Erectile Dysfunction/epidemiology , Erectile Dysfunction/therapy , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/prevention & control , Cost-Benefit Analysis , Risk Factors , Switzerland/epidemiology , Heart Disease Risk FactorsABSTRACT
BACKGROUND: A 3D sequence was introduced to unenhanced post-mortem cardiac magnetic resonance imaging (PMCMR) to enable multiplanar coronary artery image analysis and to investigate its diagnostic accuracy for the diagnosis of coronary artery stenosis and thrombosis. MATERIALS AND METHODS: N = 200 forensic cases with suspected coronary artery pathology underwent 3 Tesla PMCMR (sequence used: T2 weighted transversal 3D turbo spin echo) before autopsy. Main coronary artery stenosis and thrombosis were assessed in PMCMR by multiplanar image analysis by two observers. Coronary artery histology was determined as the gold standard and compared to PMCMR. Sensitivity, specificity, negative (NPV) and positive predictive values (PPV) with 95% confidence intervals were calculated. RESULTS: For all coronary arteries combined, sensitivity was 75% (PPV 73%) for the diagnosis of stenosis and 72% (PPV 71%) for the diagnosis of thrombosis. Specificity was 92% (NPV 90%) for correct diagnosis of non-existing stenosis and 97% (NPV 97%) for non-existing thrombosis. Sensitivity for correct diagnosis of different degrees of stenosis ranged between 67% and 80% (PPVs 67-82%); specificity ranged between 96% and 99% (NPVs 96-99%). CONCLUSION: Multiplanar PMCMR coronary artery stenosis and thrombosis assessment based on an unenhanced T2 weighted 3D sequence provide moderate sensitivity and high specificity for the diagnosis of coronary artery stenosis and/or thrombosis. Hence, 3D T2w PMCMR cannot reliably detect existing coronary artery stenosis and thrombosis but may be particularly useful for the exclusion of stenosis or thrombosis of the main coronary arteries.
Subject(s)
Coronary Stenosis , Thrombosis , Humans , Constriction, Pathologic , Sensitivity and Specificity , Magnetic Resonance Imaging/methods , Thrombosis/diagnostic imaging , Coronary Stenosis/diagnostic imagingABSTRACT
BACKGROUND: Venous leak appears to be the most common cause of vasculogenic erectile dysfunction (ED), which can be treated with venous embolization. Traditionally, conventional cavernosography was used for the diagnosis and treatment planning of venous leak. Recently, computed tomography (CT) cavernosography was introduced as a novel cross-sectional imaging method proposed to be advantageous over conventional cavernosography. We created a novel management algorithm for diagnosing venous leak including CT cavernosography as an imaging modality. In order to provide a broader basis for our management algorithm, a systematic literature review was conducted. MAIN BODY: In this article we systematically review relevant literature on using CT cavernosography for the diagnosis and treatment planning in ED patients with venous leak following the PRISMA selection process. Nine full-text articles were included in the review and assigned a level of evidence grade (all grade II). Two studies (2/9) compared the results of conventional cavernosography with those of CT cavernosography which was superior for site-specific venous leak identification (19.4% vs. 100%, respectively). CT cavernosography is a more detailed imaging method that is faster to perform, exposes the patient to less radiation, and requires less contrast material. In one study (1/9), CT cavernosography was used for diagnostic purposes only. Eight studies (8/9) cover both, diagnostic imaging and treatment planning including embolization (1/9) and sclerotherapy (2/9) of venous leak in patients with venogenic ED. Three studies (3/9) describe anatomical venous leak classifications that were established based on CT cavernosography findings for accurate mapping of superficial and/or deep venous leak and identification of mixed or more complex forms of venous leak present in up to 84% of patients. In addition to treatment planning, one study (1/9) used CT cavernosography also for follow-up imaging post treatment. CONCLUSION: CT cavernosography is superior to conventional cavernosography for diagnosis and treatment planning in patients with ED caused by venous leak (grade II levels of evidence). Consequently, CT cavernosography should be included in management algorithms for ED patients with suspected venous leak.
ABSTRACT
PURPOSE: Endovascular therapy of erection-related arteries was shown to be a promising treatment option for patients with severe erectile dysfunction. Purpose of this study was to assess the longer-term safety and clinical success rate of endovascular revascularization of erection-related arteries with the Angiolite BTK stent in patients with arteriogenic erectile dysfunction. MATERIALS AND METHODS: A total of 147 consecutive men (63.5±9.3 years) with erectile dysfunction due to 345 atherosclerotic lesions underwent endovascular revascularization. Patients received an International Index of Erectile Function (IIEF)-15 questionnaire at 30.3±7.2 months (follow-up [FU] period no less than 18 months) after stenting. An improvement by 4 points in the erectile function domain consisting of 6 questions (IIEF-6) was defined as minimal clinically important difference (MCID). RESULTS: Technical success was achieved in 99% of lesions. One major adverse event occurred after endovascular revascularization. Sixty-eight (46%) patients completed their latest FU at least 18 months following the last intervention. Minimal clinically important difference was achieved in 54% (37/68) of patients. CONCLUSIONS: In patients with arteriogenic erectile dysfunction not responding to phosphodiesterase-5-inhibitors (PDE-5-Is), endovascular therapy with a novel thin-strut sirolimus-eluting stent is a safe and effective treatment option during short- and longer-term FU. CLINICAL IMPACT: Patients with severe erectile dysfunction profit greatly from endovascular therapy of erection-related arteries. Stable clinical outcomes are seen beyond a 1-year timeframe. It is proven that, the drug-eluting stent therapy for atherosclerotic ED in patients who have not responded to PDE-5-I therapy is safe and effective during longer-term follow-up.
ABSTRACT
Background: Atherosclerotic disease of erection-related arteries is a major reason for erectile dysfunction (ED). Lp(a) has been implied in the pathophysiology of atherosclerosis in the coronary and lower limb arteries. Here, we investigated if Lp(a) plays a specific role in ED due with symptomatic pelvic artery atherosclerosis. Patients and methods: Out of 276 consecutive patients treated for ED with angioplasties on proximal (69%) and distal (31%, distal to Alcock channel) erection-related arteries, 236 patients (age: 62±10 years) of which Lp(a) values were available were retrospectively analyzed. Results: The baseline International Index of Erectile Function-15 (IIEF-15) score was 29±15 and significantly increased to 43±20 (increase: 14±21) after treatment at average follow up of 286±201 days. In 25%, Lp(a) values were elevated to more than 30 mg/dL. Hypercholesterolemia, coronary, lower extremity peripheral, and polyvascular disease were more common in patients with Lp(a) ≥60 mg/dl. Anatomic arterial lesion distribution (proximal/distal), improvement in IIEF-15 and clinically driven re-intervention rate (overall 7%) did not differ between patients with <30, 30-59, and ≥60 mg/dL Lp(a). Conclusions: While angioplasty is an effective therapy for ED of arterial origin in patients with obstruction of erection-related arteries, Lp(a) does not seem to play a major role for clinical outcomes in these patients.
Subject(s)
Atherosclerosis , Erectile Dysfunction , Impotence, Vasculogenic , Male , Humans , Middle Aged , Aged , Erectile Dysfunction/diagnosis , Erectile Dysfunction/therapy , Retrospective Studies , Impotence, Vasculogenic/diagnosis , Impotence, Vasculogenic/therapy , Angioplasty/adverse effects , ArteriesABSTRACT
ABSTRACT: Interstitial lung disease (ILD) is now diagnosed by an ILD-board consisting of radiologists, pulmonologists, and pathologists. They discuss the combination of computed tomography (CT) images, pulmonary function tests, demographic information, and histology and then agree on one of the 200 ILD diagnoses. Recent approaches employ computer-aided diagnostic tools to improve detection of disease, monitoring, and accurate prognostication. Methods based on artificial intelligence (AI) may be used in computational medicine, especially in image-based specialties such as radiology. This review summarises and highlights the strengths and weaknesses of the latest and most significant published methods that could lead to a holistic system for ILD diagnosis. We explore current AI methods and the data use to predict the prognosis and progression of ILDs. It is then essential to highlight the data that holds the most information related to risk factors for progression, e.g., CT scans and pulmonary function tests. This review aims to identify potential gaps, highlight areas that require further research, and identify the methods that could be combined to yield more promising results in future studies.
Subject(s)
Artificial Intelligence , Lung Diseases, Interstitial , Humans , Lung Diseases, Interstitial/diagnostic imaging , Prognosis , Tomography, X-Ray Computed/methods , Radiologists , Lung/diagnostic imagingABSTRACT
The purpose of this study was to define relevant intercostal artery (ICA) anatomy potentially impacting the safety of thoracic percutaneous interventional procedures. An ICA abutting the upper rib and running in the subcostal groove was defined as the lowest risk zone for interventions requiring a supracostal needle puncture. A theoretical high-risk zone was defined by the ICA coursing in the lower half of the intercostal space (ICS), and a theoretical moderate-risk zone was defined by the ICA coursing below the subcostal groove but in the upper half of the ICS. Arterial phase computed tomography data from 250 patients were analyzed, revealing demographic variability, with high-risk zones extending more laterally with advancing age and with more cranial ribs. Overall, within the 97.5th percentile, an ICS puncture >7-cm lateral to the spinous process incurs moderate risk and >10-cm lateral incurs the lowest risk.
Subject(s)
Ribs , Thoracic Wall , Arteries/anatomy & histology , Arteries/diagnostic imaging , Humans , Punctures , Ribs/diagnostic imaging , Tomography, X-Ray Computed/methodsABSTRACT
BACKGROUND: The underlying etiologies of erectile dysfunction may be manifold. Among them, vasculogenic etiologies are of increasing relevance and are not strictly limited to the elderly population. According to recent study, venogenic erectile dysfunction appears to be even more relevant than arteriogenic erectile dysfunction. Venogenic erectile dysfunction due to venous leakage causes insufficient penile blood retention. Proper diagnosis of venous leakage should include both color Doppler flow analysis and computed tomography cavernosography for adequate patient selection and treatment planning. Besides surgical ligation of penile draining veins, endovascular treatment methods may demonstrate more promising results. Especially endovascular embolization of venous leakage using an anterograde access via deep dorsal penile veins appears to be more beneficial for patients' clinical outcome and awareness of this technique should be raised among endovascular interventionalists. CASE PRESENTATION: A 47-year-old man was diagnosed with venogenic erectile dysfunction due to venous leakage on color Doppler flow analysis and computed tomography cavernosography. He did not respond to PDE-5-inhibitors. This patient demonstrated major venous leakage of paired deep dorsal penile veins via periprostatic veins and internal pudendal veins draining into both iliohypogastric veins. This patient's venous leak was treated with endovascular embolization using an anterograde access via deep dorsal penile veins. CONCLUSION: This patient's erectile dysfunction due to venous leakage, based on findings in color Doppler flow analysis and computed tomography cavernosography, was embolized using an anterograde access via deep dorsal penile veins as a minimally-invasive endovascular treatment option.
ABSTRACT
Erectile dysfunction is a defined as recurring inability to achieve and maintain satisfactory erection for sexual intercourse associated with relevant life impairment. The underlying etiologies may be manifold and complex. Currently, vascular etiologies are highly prevalent especially amongst elderly men. Of special interest, especially venogenic causes are of increasing relevance. Therapeutic options comprise risk factor modification, pharmacotherapy, surgical treatment, and endovascular treatment. Especially endovascular treatment options have recently increased in popularity including transcatheter embolization procedures for veno-occlusive dysfunction.
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PURPOSE: To evaluate the efficacy of superselective transcatheter arterial embolization (TAE) in the treatment of acute peripancreatic bleeding complications. METHODS: During a 9-year period, 44 patients with acute bleeding of the peripancreatic arteries underwent TAE in our institution. Thirty-eight patients were treated using microcatheters and 6 patients with a diagnostic catheter. Embolic agents included coils (n = 38), polyvinyl alcohol (PVA) particles (n = 2), isobutyl cyanoacrylate (n = 2), coils plus PVA particles (n = 1), and coils plus isobutyl cyanoacrylate (n = 1). Outcome measures included technical success, clinical success, and the rate of complications. RESULTS: Identified bleeding sources included gastroduodenal artery (n = 14), splenic artery (n = 9), pancreaticoduodenal artery (n = 6), common hepatic artery (n = 5), superior mesenteric artery branches (n = 4), proper hepatic artery (n = 3), and dorsal/transverse pancreatic artery (n = 3). Technical success with effective control of active bleeding was achieved in 41/44 patients (93 %). Clinical success attributed to TAE alone was documented in 40/44 patients (91 %). The rate of major complications was 2 % including death in one patient. CONCLUSIONS: Superselective TAE allows effective, minimally invasive control of acute peripancreatic bleeding complications with a low rate of therapeutically relevant complications.
Subject(s)
Embolization, Therapeutic , Hemorrhage , Hepatic Artery , Humans , Pancreas , Retrospective Studies , Treatment OutcomeABSTRACT
To evaluate the sensitivity of postmortem computed tomography (PMCT) in rib fracture detection validated against autopsy. Fifty-one forensic cases underwent a postmortem CT prior to forensic autopsy. Two image readers (radiologist and forensic pathologist) assessed high resolution CT data sets for rib fractures. Correct recognition rates (CRR), sensitivity and specificity values were calculated over all observations as well as individually for every rib and region. Additionally, for partial rib fractures the sensitivity of autopsy was calculated vice versa. 3876 entries in each study protocol (autopsy, PMCT radiologist and PMCT forensic pathologist) were investigated. A total of 690 fractures (autopsy), 491 (PMCT and radiologist) and 559 (PMCT and forensic pathologist) were detected. The CRR was 0.85. Sensitivity and specificity of PMCT for rib fracture detection were 0.63 (0.58 radiologist, 0.68 forensic pathologist) and 0.97 (both readers 0.97), respectively. Low CRR and sensitivity values were obtained for antero-lateral fractures. Partial rib fractures were better detected by PMCT. PMCT has a rather low sensitivity for rib fracture detection when validated against autopsy and indicates that clinical CT may also demonstrate a reasonable number of false negatives. Partial rib fractures often remain undetected at autopsy.
Subject(s)
Autopsy , Multidetector Computed Tomography , Rib Fractures/diagnostic imaging , Rib Fractures/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Male , Middle Aged , Observer Variation , Sensitivity and Specificity , Young AdultABSTRACT
Within the past 15 years, significant advances in the imaging of multiorgan and complex trauma primarily due to the improvement of cross-sectional imaging have resulted in the optimization of the expedient diagnosis and management of the polytrauma patient. At the forefront, multidetector computed tomography (MDCT) has become the cornerstone of modern emergency departments and trauma centers. In many institutions, MDCT is the de facto diagnostic tool upon trauma activation. In the setting of pelvic imaging, MDCT (with its high spatial resolution and sensitivity as well as short acquisition times) allows for rapid identification and assessment of pelvic hemorrhage leading to faster triage and definitive management. In trauma centers throughout the world, angiography and minimally invasive catheter-based embolization techniques performed by interventional radiologists have become the standard of care for patients with acute pelvic trauma and related multiorgan hemorrhage. In an interdisciplinary setting, embolization may be performed either alone or as an adjunct procedure with open or closed reduction and stabilization techniques. A team-based approach involving multiple disciplines (e.g., radiology, traumatology, orthopedic surgery, intensive care medicine) is crucial to monitor and treat the actively bleeding patient appropriately.
Subject(s)
Embolization, Therapeutic , Fractures, Bone/complications , Fractures, Bone/diagnostic imaging , Hemorrhage/diagnostic imaging , Hemorrhage/etiology , Hemorrhage/therapy , Pelvis/diagnostic imaging , Pelvis/injuries , Tomography, X-Ray Computed/methods , Wounds, Nonpenetrating/complications , Acute Disease , Angiography/methods , Contrast Media , Humans , Imaging, Three-DimensionalSubject(s)
Elbow , Nerve Sheath Neoplasms/secondary , Soft Tissue Neoplasms/diagnosis , Thoracic Neoplasms/secondary , Adult , Diagnosis, Differential , Disease Progression , Elbow/surgery , Fatal Outcome , Female , Humans , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Neoplasm Grading , Nerve Sheath Neoplasms/diagnosis , Nerve Sheath Neoplasms/pathology , Nerve Sheath Neoplasms/surgery , Palliative Care , Soft Tissue Neoplasms/pathology , Soft Tissue Neoplasms/surgery , Thoracic Neoplasms/diagnosis , Thoracic Neoplasms/pathology , Thoracic Neoplasms/surgery , Tomography, X-Ray Computed , UltrasonographyABSTRACT
OBJECTIVE: Comparison of arterial and venous coronary artery bypass flow measurements using 3-T magnetic resonance (MR) phase contrast in correlation with intraoperative Doppler flow measurements. METHODS: Fifty-six coronary bypasses (right coronary artery n=18, left internal mammary artery to left anterior descending artery n=16, marginal artery n=7, circumflex artery n=7, diagonal artery n=6, left anterior descending artery n=1, and right internal mammary artery to right coronary artery n=1) were studied in 27 asymptomatic patients. In this prospective study, each bypass was studied intra-operatively using Doppler flow measurement. Within one week post surgery, patients were studied using a 3-T MR scanner (Magnetom Verio, Siemens, Erlangen, Germany) using velocity encoded phase-contrast flow measurements. RESULTS: Intraoperative Doppler flow measurements demonstrated regular flow patterns in all vascular territories supplied. All bypasses were patent on MRI and flow measurement results were as follows: median flow 60ml/min (interquartile range (IQR): 37.5-78.5ml/min). For comparison, the corresponding median intraoperative flow was 58ml/min (IQR: 41-80ml/min) (p<0.001; R=0.44). Linear regression analysis demonstrated a significant correlation for venous bypasses (p=0.0002; R=0.48), but not for arterial bypasses (p=0.09; R=0.24). CONCLUSION: This study demonstrated that MR flow measurements of venous bypass grafts agreed more with Doppler than arterial bypass grafts. However, bypass patency was confirmed for all patients. In the future, this technique may be used for non invasive coronary bypass graft follow-up.
Subject(s)
Arteries/transplantation , Coronary Artery Bypass/methods , Coronary Artery Disease/physiopathology , Coronary Artery Disease/surgery , Coronary Circulation , Magnetic Resonance Angiography/methods , Saphenous Vein/transplantation , Aged , Aged, 80 and over , Blood Flow Velocity , Coronary Artery Disease/pathology , Female , Humans , Male , Middle Aged , Saphenous Vein/physiopathology , Treatment OutcomeABSTRACT
INTRODUCTION: Preoperative mapping of the arterial spinal supply prior to thoracoabdominal aortic aneurysm repair is highly relevant because of high risk for postoperative ischemic spinal cord injuries such as paraparesis or paraplegia. METHODS: Twenty-four consecutive patients prior to surgical thoracoabdominal aortic aneurysm repair were investigated. All patients underwent steady-state MR angiography (MRA) of the spinal vasculature with 3-T MRI. The sequence used was a steady-state coronary 3D FLASH with 0.7-mm isotropic voxels. MRA was performed using an intravasal contrast agent. Studies were evaluated by three readers including delineation of arterial spinal supply including both aortic origin and spinal canal entry by three readers. RESULTS: Identification and localization of the Adamkiewicz artery and its spinal canal entry was successful in all patients. Overall depiction of the vascular anatomy was graded as very good in 3 (12.5%), good in 14 (58.4%), sufficient in 5 (20.8%), and poor in 2 (8.3%) patients. Depiction of segmental artery aortic exit level was graded as good in 6 (25.0%), sufficient in 10 (41.7%), poor in 4 (16.7%) and not identifiable in 4 (16.7%) patients. Delineation of segmental artery entry level into the spinal canal was graded as very good in 4 (16.7%), good in 11 (45.8%), sufficient in 6 (25.0%), and poor in 3 (12.5%) patients. CONCLUSIONS: The use of 3-T MRA with an intravascular contrast agent and steady-state enables AKA localization including its segmental arteries with regard to the level of aortic origin and spinal canal entry in most patients.
Subject(s)
Aortic Aneurysm/pathology , Aortic Aneurysm/surgery , Arteries/pathology , Gadolinium , Magnetic Resonance Angiography/methods , Organometallic Compounds , Spinal Cord/blood supply , Spinal Cord/pathology , Adult , Aged , Contrast Media/administration & dosage , Female , Gadolinium/administration & dosage , Humans , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Injections, Intra-Arterial , Male , Middle Aged , Organometallic Compounds/administration & dosage , Preoperative Care/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
OBJECTIVE: The purpose of this study was to simulate pulmonary emboli (PE) and image quality at low tube energy and reduced contrast material volume in normal-dose pulmonary CT angiography (CTA) images and to analyze the diagnostic accuracy with normal- and low-dose pulmonary CTA. MATERIALS AND METHODS: Normal-dose pulmonary CTA examinations using 120 kVp and 100 mL of contrast material in 10 patients with no PE were retrospectively selected. The image characteristics of an 80-kVp low-dose pulmonary CTA protocol (patient exposure reduction, 57%) with 75 mL of contrast material were simulated. Four different sets of filling defects were computer simulated in identical locations in each normal-dose and corresponding low-dose examination, equaling 783 PE in 40 normal-dose and 40 low-dose datasets. Ten normal-dose and 10 low-dose examinations contained no emboli and were used as controls. The 100 pulmonary CTA studies were randomly assessed by three readers blinded to PE location and image quality. The results were assessed by nonparametric tests and Student t tests. RESULTS: No difference was found between the CT protocols in terms of sensitivity, specificity, and positive and negative diagnostic likelihood ratios at all ramification levels of the pulmonary arteries (p = 0.343-1). The overall sensitivity and specificity with the normal and simulated low-dose protocols were 79.9% versus 81.3% and 98.0% versus 98.2% (p = 0.444 and 0.702), respectively. The diagnostic confidence (2.81 ± 0.39 vs 2.77 ± 0.47; p = 0.297) and overall image quality (3.92 ± 0.52 vs 3.83 ± 0.54; p = 0.216) were similar at 120 kV and 80 kV. CONCLUSION: The intraindividual comparison of diagnostic accuracy with normal-dose and simulated low-dose pulmonary CTA protocols revealed no difference under experimental conditions.
Subject(s)
Angiography/methods , Pulmonary Embolism/diagnostic imaging , Tomography, X-Ray Computed/methods , Aged , Algorithms , Computer Simulation , Contrast Media/administration & dosage , Female , Humans , Male , Radiation Dosage , Retrospective Studies , Sensitivity and Specificity , Statistics, NonparametricABSTRACT
PURPOSE: To assess if finite element (FE) models can be used to predict deformation of the femoropopliteal segment during knee flexion. METHODS: Magnetic resonance angiography (MRA) images were acquired on the lower limbs of 8 healthy volunteers (5 men; mean age 28 ± 4 years). Images were taken in 2 natural positions, with the lower limb fully extended and with the knee bent at ~ 40°. Patient-specific FE models were developed and used to simulate the experimental situation. The displacements of the artery during knee bending as predicted by the numerical model were compared to the corresponding positions measured on the MRA images. RESULTS: The numerical predictions showed a good overall agreement between the calculated displacements of the motion measures from MRA images. The average position error comparing the calculated vs. actual displacements of the femoropopliteal intersection measured on the MRA was 8 ± 4 mm. Two of the 8 subjects showed large prediction errors (average 13 ± 5 mm); these 2 volunteers were the tallest subjects involved in the study and had a low body mass index (20.5 kg/m²). CONCLUSION: The present computational model is able to capture the gross mechanical environment of the femoropopliteal intersection during knee bending and provide a better understanding of the complex biomechanical behavior. However, results suggest that patient-specific mechanical properties and detailed muscle modeling are required to provide accurate patient-specific numerical predictions of arterial displacement. Further adaptation of this model is expected to provide an improved ability to predict the multiaxial deformation of this arterial segment during leg movements and to optimize future stent designs.
Subject(s)
Computer Simulation , Femoral Artery/physiology , Finite Element Analysis , Knee/blood supply , Models, Cardiovascular , Muscle Contraction , Numerical Analysis, Computer-Assisted , Popliteal Artery/physiology , Adult , Biomechanical Phenomena , Body Height , Body Mass Index , Female , Femoral Artery/anatomy & histology , Humans , Magnetic Resonance Angiography , Male , Pilot Projects , Popliteal Artery/anatomy & histology , Stress, MechanicalABSTRACT
OBJECTIVE: The purpose of this article is to assess the impact of large patient size on the detection of hypovascular liver tumors with MDCT and the effect of a noise filter on image quality and lesion detection in obese patients. MATERIALS AND METHODS: A liver phantom with 45 hypovascular tumors (diameters of 5, 10, and 15 mm) was placed into two water containers mimicking intermediate and large patients. The containers were scanned with a 64-MDCT scanner. The CT dataset from the large phantom was postprocessed using a noise filter. The image noise was measured and the contrast-to-noise ratio (CNR) of the tumors was calculated. Tumor detection was independently performed by three radiologists in a blinded fashion. RESULTS: The application of the noise filter in the large phantom yielded a reduction of image noise by 42% (p < 0.0001). The CNR values of the tumors in the nonfiltered and filtered large phantom were lower than that in the intermediate phantom (p < 0.05). In the non-filtered and filtered large phantom, 25% and 19% fewer tumors, respectively, were detected on average compared with the intermediate phantom (p < 0.01). CONCLUSION: The risk of missing hypovascular liver tumors with CT is substantially increased in large patients. A noise filter improves image quality in obese patients.