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Rogers AJ, Light ED, Smith SW. 3-D ultrasound guidance of autonomous robot for location of ferrous shrapnel. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2009; 56:1301-1303. [PMID: 19574140 PMCID: PMC2810201 DOI: 10.1109/tuffc.2009.1185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vibrations can be induced in ferromagnetic shrapnel by a variable electromagnet. Real time 3-D color Doppler ultrasound located the induced motion in a needle fragment and determined its 3-D position in the scanner coordinates. This information was used to guide a robot which moved a probe to touch the shrapnel fragment.
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Smith SW, Clark M, Nelson J, Heegaard W, Lufkin KC, Ruiz E. Emergency department skull trephination for epidural hematoma in patients who are awake but deteriorate rapidly. J Emerg Med 2009; 39:377-83. [PMID: 19535215 DOI: 10.1016/j.jemermed.2009.04.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 12/30/2008] [Accepted: 04/11/2009] [Indexed: 11/20/2022]
Abstract
BACKGROUND Blunt head trauma patients who have been alert but are deteriorating (talk and deteriorate [T&D]) due to a rapidly expanding epidural hematoma (EDH) usually have poor outcome if they must wait for hospital transfer for evacuation. We therefore have continued to teach skull trephination to emergency physicians (EPs). We are unaware of any literature on EP trephination for EDH in the age of computed tomography (CT) scanning. METHODS Patients with EDH from blunt trauma, either in our institution or known to our graduate network, who were T&D with anisocoria despite intubation plus medical therapy, and who had pre-transfer EP trephination, were compared to those who were transferred without trephination. RESULTS There were 5 patients with blunt trauma and CT-proven EDH who were T&D with anisocoria who underwent Emergency Department (ED) trephination at outlying hospitals before transfer. All 5 had improvement in condition and good outcomes. Three had complete recovery without disability and 2 others had mild disability with good cognitive function. None had complications. Two patients with T&D and anisocoria were transferred without trephination. Both had good neurologic outcomes. The mean time to pressure relief in the trephination group vs. transfer group was 55 vs. 207 min, respectively. CONCLUSION In T&D patients with CT-proven EDH and anisocoria, ED skull trephination before transfer resulted in uniformly good outcomes without complications. Time to relief of intracranial pressure was significantly shorter with trephination. Neurologic outcomes were not different.
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Smith SW. Electrocardiographic Research on Left Bundle Branch Block Must Use Angiographic Outcomes and Proportionality If It Is to Guide Reperfusion Therapy. Ann Emerg Med 2009; 53:691-2; author reply 692-3. [DOI: 10.1016/j.annemergmed.2008.10.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 10/22/2008] [Accepted: 10/22/2008] [Indexed: 11/25/2022]
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Herickhoff CD, Light ED, Bing KF, Mukundan S, Grant GA, Wolf PD, Smith SW. Dual-mode intracranial catheter integrating 3D ultrasound imaging and hyperthermia for neuro-oncology: feasibility study. ULTRASONIC IMAGING 2009; 31:81-100. [PMID: 19630251 PMCID: PMC2810199 DOI: 10.1177/016173460903100201] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this study, we investigated the feasibility of an intracranial catheter transducer with dual-mode capability of real-time 3D (RT3D) imaging and ultrasound hyperthermia, for application in the visualization and treatment of tumors in the brain. Feasibility is demonstrated in two ways: first by using a 50-element linear array transducer (17 mm x 3.1 mm aperture) operating at 4.4 MHz with our Volumetrics diagnostic scanner and custom, electrical impedance-matching circuits to achieve a temperature rise over 4 degrees C in excised pork muscle, and second, by designing and constructing a 12 Fr, integrated matrix and linear-array catheter transducer prototype for combined RT3D imaging and heating capability. This dual-mode catheter incorporated 153 matrix array elements and 11 linear array elements diced on a 0.2 mm pitch, with a total aperture size of 8.4 mm x 2.3 mm. This 3.64 MHz array achieved a 3.5 degrees C in vitro temperature rise at a 2 cm focal distance in tissue-mimicking material. The dual-mode catheter prototype was compared with a Siemens 10 Fr AcuNav catheter as a gold standard in experiments assessing image quality and therapeutic potential and both probes were used in an in vivo canine brain model to image anatomical structures and color Doppler blood flow and to attempt in vivo heating.
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MESH Headings
- Animals
- Brain Neoplasms/diagnostic imaging
- Brain Neoplasms/therapy
- Catheterization/instrumentation
- Catheterization/methods
- Dogs
- Equipment Design
- Feasibility Studies
- Hyperthermia, Induced/instrumentation
- Hyperthermia, Induced/methods
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Phantoms, Imaging
- Swine
- Transducers
- Ultrasonography, Doppler, Color/instrumentation
- Ultrasonography, Doppler, Color/methods
- Ultrasonography, Interventional/instrumentation
- Ultrasonography, Interventional/methods
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180
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Zvosec DL, Smith SW, Hall BJ. Three deaths associated with use of Xyrem®. Sleep Med 2009; 10:490-3. [PMID: 19269893 DOI: 10.1016/j.sleep.2009.01.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 01/10/2009] [Accepted: 01/14/2009] [Indexed: 10/21/2022]
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181
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Rokos IC, French WJ, Koenig WJ, Stratton SJ, Nighswonger B, Strunk B, Jewell J, Mahmud E, Dunford JV, Hokanson J, Smith SW, Baran KW, Swor R, Berman A, Wilson BH, Aluko AO, Gross BW, Rostykus PS, Salvucci A, Dev V, McNally B, Manoukian SV, King SB. Integration of Pre-Hospital Electrocardiograms and ST-Elevation Myocardial Infarction Receiving Center (SRC) Networks. JACC Cardiovasc Interv 2009; 2:339-46. [DOI: 10.1016/j.jcin.2008.11.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 11/18/2008] [Accepted: 11/19/2008] [Indexed: 01/04/2023]
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182
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Apple FS, Pearce LA, Smith SW, Kaczmarek JM, Murakami MM. Role of monitoring changes in sensitive cardiac troponin I assay results for early diagnosis of myocardial infarction and prediction of risk of adverse events. Clin Chem 2009; 55:930-7. [PMID: 19299542 DOI: 10.1373/clinchem.2008.114728] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND We sought to determine the diagnostic accuracy of the cardiac troponin I (cTnI) VITROS(R) Troponin I-ES assay for early detection of acute myocardial infarction (AMI) and for risk prediction of adverse events in patients with symptoms of acute coronary syndrome (ACS). METHODS cTnI was measured on admission and approximately 6 h postadmission in 381 patients. The 99th percentile cTnI concentration (0.034 microg/L) and change [delta (delta)] between admission and follow-up concentrations were evaluated in diagnostic sensitivity and specificity calculations. Risk of cardiac event or death within 60 days was evaluated by Cox proportional hazards regression. RESULTS AMI occurred in 52 patients. Diagnostic sensitivities (95% CI) of admission and follow-up cTnIs for AMI were 69% (55%-81%) and 94% (84%-99%), respectively. The corresponding specificities (95% CI) were 78% (73%-82%) and 81% (77%-85%), and ROC curve areas were 0.82 vs 0.96 (P < 0.001). Deltas between admission and follow-up cTnI >30% had a sensitivity of 75% (95% CI 61%-86%) and a specificity of 91% (95% CI 87%-94%). During follow-up, 1 cardiac death, 2 noncardiac deaths, 52 AMIs, 6 coronary artery bypass grafts, and 43 percutanous coronary interventions occurred in 62 patients. A delta cTnI >30%, when added to either initial cTnI >0.034 microg/L or follow-up cTnI >0.034 microg/L, improved risk stratification for cardiac event or death (P < 0.001). CONCLUSIONS Admission cTnI measured by the VITROS ES assay is a sensitive biomarker for detection of AMI. Utilizing >30% cTnI delta in addition to either the baseline or follow-up concentration improved both specificity and risk assessment in patients presenting with symptoms of ACS.
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183
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Smith SW, Ivancevich NM, Lindsey BD, Whitman J, Light E, Fronheiser M, Nicoletto HA, Laskowitz DT. The ultrasound brain helmet: feasibility study of multiple simultaneous 3D scans of cerebral vasculature. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:329-338. [PMID: 18947918 DOI: 10.1016/j.ultrasmedbio.2008.08.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 06/25/2008] [Accepted: 08/21/2008] [Indexed: 05/27/2023]
Abstract
We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time three-dimensional (3D) scans of the cerebral vasculature from temporal and suboccipital acoustic windows of the skull. The transducer hardware and software of the Volumetrics Medical Imaging (Durham, NC, USA) real-time 3D scanner were modified to support dual 2.5 MHz matrix arrays of 256 transmit elements and 128 receive elements which produce two simultaneous 64 degrees pyramidal scans. The real-time display format consists of two coronal B-mode images merged into a 128 degrees sector, two simultaneous parasagittal images merged into a 128 degrees x 64 degrees C-mode plane and a simultaneous 64 degrees axial image. Real-time 3D color Doppler scans from a skull phantom with latex blood vessel were obtained after contrast agent injection as a proof of concept. The long-term goal is to produce real-time 3D ultrasound images of the cerebral vasculature from a portable unit capable of internet transmission thus enabling interactive 3D imaging, remote diagnosis and earlier therapeutic intervention. We are motivated by the urgency for rapid diagnosis of stroke due to the short time window of effective therapeutic intervention.
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184
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Apple FS, Smith SW, Pearce LA, Murakami MM. Assessment of the multiple-biomarker approach for diagnosis of myocardial infarction in patients presenting with symptoms suggestive of acute coronary syndrome. Clin Chem 2008; 55:93-100. [PMID: 19028826 DOI: 10.1373/clinchem.2008.102905] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Cardiac troponin is the preferred biomarker for detecting acute myocardial injury and infarction (MI). We studied whether multiple biomarkers of numerous pathophysiological pathways would increase the diagnostic accuracy for detecting MI. METHODS Seven biomarkers [myeloperoxidase, soluble CD40 ligand, placental growth factor, matrix metalloproteinase 9 (MMP-9), high-sensitivity C-reactive protein (hsCRP), cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic peptide] and estimated glomerular filtration rate were measured in 457 patients presenting on admission with symptoms suggestive of acute coronary syndrome. Twenty-five patients (5.4%) received MI diagnoses. Clinical sensitivities and specificities were evaluated from 99th-percentile reference values. Forward and backward stepwise logistic regression modeling techniques were used to identify biomarkers that were independently predictive of MI. RESULTS Biomarker sensitivities ranged from 20% to 96%, and specificities ranged from 19% to 89%. MMP-9 had the highest sensitivity, but its specificity was 19%. cTnI demonstrated a sensitivity of 72% (95% CI, 51%-88%) and a specificity of 89% (95% CI, 85%-92%). In multivariate models, cTnI (P < 0.001) and either hsCRP (P = 0.009) or MMP-9 (P = 0.03) were independently predictive of MI. Addition of hsCRP or MMP-9 increased the specificity to 95% (95% CI, 92%-97%) or 91% (95% CI, 88%-94%), respectively, but reduced the sensitivity to 56% (95% CI, 35%-76%) and 68% (95% CI, 47%-85%) relative to cTnI alone. CONCLUSIONS Our findings indicate that the most clinically accurate biomarker for the early diagnosis of MI is the use of cTnI alone, rather than a multiple-biomarker approach, when an analytically robust cardiac troponin assay based on the 99th percentile is used.
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185
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Reddy KE, Light ED, Rivera DJ, Kisslo JA, Smith SW. Color Doppler imaging of cardiac catheters using vibrating motors. ULTRASONIC IMAGING 2008; 30:247-250. [PMID: 19514134 PMCID: PMC2804844 DOI: 10.1177/016173460803000408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A miniature motor rotating at 11,000 rpm was attached onto the proximal end of cardiac electrophysiological (EP) catheters in order to produce vibrations at the tip that were then visualized by color Doppler on ultrasound scanners. The catheter tip was imaged within a vascular graft submerged in a water tank using the Volumetrics Medical Imaging 3D scanner, the Siemens Sonoline Antares 2D scanner and the Philips ie33 3D ultrasound scanner with TEE probe. The vibrating catheter tip was visualized in each case, although results varied with the color Doppler properties of the individual scanner.
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186
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Ivancevich NM, Pinton GF, Nicoletto HA, Bennett E, Laskowitz DT, Smith SW. Real-time 3-D contrast-enhanced transcranial ultrasound and aberration correction. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:1387-95. [PMID: 18395321 PMCID: PMC2597560 DOI: 10.1016/j.ultrasmedbio.2008.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 12/13/2007] [Accepted: 01/18/2008] [Indexed: 05/11/2023]
Abstract
Contrast-enhanced (CE) transcranial ultrasound (US) and reconstructed 3-D transcranial ultrasound have shown advantages over traditional methods in a variety of cerebrovascular diseases. We present the results from a novel ultrasound technique, namely real-time 3-D contrast-enhanced transcranial ultrasound. Using real-time 3-D (RT3D) ultrasound and microbubble contrast agent, we scanned 17 healthy volunteers via a single temporal window and nine via the suboccipital window and report our detection rates for the major cerebral vessels. In 71% of subjects, both of our observers identified the ipsilateral circle of Willis from the temporal window, and in 59% we imaged the entire circle of Willis. From the suboccipital window, both observers detected the entire vertebrobasilar circulation in 22% of subjects, and in 44%, the basilar artery. After performing phase aberration correction on one subject, we were able to increase the diagnostic value of the scan, detecting a vessel not present in the uncorrected scan. These preliminary results suggest that RT3D CE transcranial US and RT3D CE transcranial US with phase aberration correction have the potential to greatly impact the field of neurosonology.
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187
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Light ED, Angle JF, Smith SW. Real-time 3-D ultrasound guidance of interventional devices. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:2066-78. [PMID: 18986903 PMCID: PMC2656286 DOI: 10.1109/tuffc.898] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We have previously developed 2-D array transducers for many real-time volumetric imaging applications. These applications include transducers operating up to 7 MHz for transthoracic imaging, up to 15 MHz for intracardiac echocardiography (ICE), 5 MHz for transesophageal echocardiography (TEE) and intracranial imaging, and 7 MHz for laparoscopic ultrasound imaging (LUS). Now we have developed a new generation of miniature ring-array transducers integrated into the catheter deployment kits of interventional devices to enable real-time 3-D ultrasound scanning for improved guidance of minimally invasive procedures. We have constructed 3 new ring transducers. The first consists of 54 elements operating at 5 MHz. Typical measured transducer element bandwidth was 25%, and the 50 Ohm round trip insertion loss was -65 dB. Average nearest neighbor cross talk was -23.8 dB. The second is a prototype 108-element transducer operating at 5 MHz. The third is a prototype 108-element ring array with a transducer center frequency of 8.9 MHz and a -6 dB bandwidth of 25%. All transducers were integrated with an 8.5 French catheter sheath of a Cook Medical, Inc. vena cava filter deployment device.
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188
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Thomas SH, Smith SW, Slater NG, Pearson TC, Treacher DF. The haemodynamic responses to venesection and the effects of cardiovascular disease. CLINICAL AND LABORATORY HAEMATOLOGY 2008; 14:201-8. [PMID: 1451400 DOI: 10.1111/j.1365-2257.1992.tb00366.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The haemodynamic effects of the venesection of one unit (450 ml) of blood over 9 min were measured using non-invasive techniques, in 14 healthy controls and 18 patients with coronary heart disease or hypertension. Venesection was associated with significant reductions in supine and standing systolic and diastolic blood pressure, stroke volume index and cardiac index, and increases in standing heart rate, in both patient groups. No significant differences were observed between the responses of subjects with and without cardiovascular disease. The authors conclude that, in contrast to established teaching, blood loss can be detected in its early stages by careful haemodynamic monitoring and that venesection can be performed safely without volume replacement in patients with stable cardiovascular disease.
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189
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Whitman J, Fronheiser MP, Smith SW. 3-D ultrasound guidance of surgical robotics using catheter transducers: feasibility study. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:1143-1145. [PMID: 18519222 DOI: 10.1109/tuffc.2008.766] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The goal of this study was to test the feasibility of using a real-time 3-D (RT3D) ultrasound scanner with matrix array catheter probes to guide a surgical robot. We tested the accuracy of using 3-D catheter transducers with the 3-D measurement software of the scanner to direct automatically a robot arm that touched two needle tips together within a water tank and inside a vascular graft. RMS measurement error ranged from 2.4 to 3.4 mm for two catheter designs.
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190
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Smith SW. From the farm to the city: Using agricultural supplies to irrigate urban landscapes. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/j.1551-8833.2008.tb09632.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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191
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Smith SW. Comment on "A Bayesian sensitivity analysis of out-of-hospital 12-lead electrocardiograms: implications for regionalization of cardiac care". Acad Emerg Med 2008; 15:488; author reply 488-9. [PMID: 18439209 DOI: 10.1111/j.1553-2712.2008.00089.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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192
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Apple FS, Smith SW, Pearce LA, Ler R, Murakami MM. Use of the Centaur TnI-Ultra Assay for Detection of Myocardial Infarction and Adverse Events in Patients Presenting With Symptoms Suggestive of Acute Coronary Syndrome. Clin Chem 2008; 54:723-8. [DOI: 10.1373/clinchem.2007.097162] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Abstract
Background: We determined the diagnostic accuracy of the Advia Centaur TnI-Ultra assay for detecting myocardial infarction (MI) and assessing risk of adverse events in patients presenting with ischemic symptoms suggestive of acute coronary syndrome.
Methods: We measured cardiac troponin I (cTnI) on admission and 6–24 h after admission (follow-up) in plasma specimens from 371 consecutive patients. The end point was the first of cardiac event or death within 60 days. We estimated survival curves using the Kaplan-Meier method and compared groups with the log rank statistic.
Results: MI was established in 49 patients (13%). Clinical sensitivities and specificities for MI based on the 99th percentile (0.04 μg/L) were 74% and 84%, respectively, on admission and 94% and 81% at follow-up. ROC curves showed significantly higher accuracy for MI in the follow-up specimen compared with admission (P = 0.001). Overall there were 2 cardiac deaths, 1 noncardiac death, 49 MIs, 7 coronary artery bypass grafts, and 36 percutaneous coronary interventions in 59 patients during follow-up. The event rate in those with cTnI <0.006 μg/L was significantly lower than in groups with cTnI 0.006–0.04 μg/L, >0.04–0.10 μg/L, or >0.10 μg/L (2.8% vs 11.1%, 24.1%, 55.1%, respectively; P <0.0001). Relative risks for the increasing cTnI cutoff groups were 3.9 (95% CI 1.2–13), 8.9 (2.4–34), and 25 (7.3–82) after adjustment for age, diabetes, history of hypertension, previous MI, and estimated glomerular filtration rate.
Conclusions: The TnI-Ultra assay is a sensitive, early diagnostic biomarker for MI and an independent predictor of adverse events at any measurable cTnI in patients with symptoms of acute coronary syndrome.
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193
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Hsu SJ, Hubert JL, Smith SW, Trahey GE. Intracardiac echocardiography and acoustic radiation force impulse imaging of a dynamic ex vivo ovine heart model. ULTRASONIC IMAGING 2008; 30:63-77. [PMID: 18939609 DOI: 10.1177/016173460803000201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Intracardiac echocardiography (ICE) has demonstrated utility in providing high-resolution cardiac ultrasound images for guidance of numerous catheter-based interventions, including radiofrequency ablations (RFA). However, the training of interventionalists and refinement of procedures involving intracardiac catheters is costly and time consuming due to necessary clinical and animal studies. As a result, research and development of ICE for other purposes is gradual and deliberate. Intracardiac acoustic radiation force impulse (ARFI) imaging has been demonstrated to be a suitable modality to monitor the progress of RFA procedures; however, a clinical protocol has been slow to develop due to the expense and demands of clinical experiments. We report on the development and use of an ex vivo heart model to evaluate ICE and intracardiac ARFI imaging. The ability of this model to provide clinically-relevant intracardiac imaging angles was investigated by inserting an intracardiac probe into the heart and imaging it from various positions and orientations. ARFI images of all four chambers also were formed. RFAs were also performed to create stiffer lesions within the right and left ventricles. Upon completion of the ablation, ARFI imaging was used to visualize the lesion and compared with images taken from pathology.The results show the ovine heart model to be a suitable apparatus for recreating several clinically-relevant intracardiac viewing angles of the heart. Also, the results indicate the potential of the heart model to be a valuable tool in the future development and refinement of a clinical protocol for intracardiac ARFI imaging based guidance and assessment of cardiac radiofrequency ablations.
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194
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Smith SW, Heegaard W, Bachour FA, Brady WJ. Acute myocardial infarction with left bundle-branch block: disproportional anterior ST elevation due to right ventricular myocardial infarction in the presence of left bundle-branch block. Am J Emerg Med 2008; 26:342-7. [DOI: 10.1016/j.ajem.2007.05.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 05/25/2007] [Indexed: 11/27/2022] Open
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195
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Fronheiser MP, Idriss SF, Wolf PD, Smith SW. Vibrating interventional device detection using real-time 3-D color Doppler. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:1355-62. [PMID: 18599423 PMCID: PMC2639786 DOI: 10.1109/tuffc.2008.798] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Ultrasound image guidance of interventional devices during minimally invasive surgery provides the clinician with improved soft tissue contrast while reducing ionizing radiation exposure. One problem with ultrasound image guidance is poor visualization of the device tip during the clinical procedure. We have described previously guidance of several interventional devices using a real-time 3-D (RT3-D) ultrasound system with 3-D color Doppler combined with the ColorMark technology. We then developed an analytical model for a vibrating needle to maximize the tip vibrations and improve the reliability and sensitivity of our technique. In this paper, we use the analytical model and improved radiofrequency (RF) and color Doppler filters to detect two different vibrating devices in water tank experiments as well as in an in vivo canine experiment. We performed water tank experiments with four different 3- D transducers: a 5 MHz transesophageal (TEE) probe, a 5 MHz transthoracic (TTE) probe, a 5 MHz intracardiac catheter (ICE) transducer, and a 2.5 MHz commercial TTE probe. Each transducer was used to scan an aortic graft suspended in the water tank. An atrial septal puncture needle and an endomyocardial biopsy forceps, each vibrating at 1.3 kHz, were inserted into the vascular graft and were tracked using 3-D color Doppler. Improved RF and wall filters increased the detected color Doppler sensitivity by 14 dB. In three simultaneous planes from the in vivo 3-D scan, we identified both the septal puncture needle and the biopsy forceps within the right atrium using the 2.5 MHz probe. A new display filter was used to suppress the unwanted flash artifact associated with physiological motion.
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196
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Klein SM, Fronheiser MP, Reach J, Nielsen KC, Smith SW. Piezoelectric Vibrating Needle and Catheter for Enhancing Ultrasound-Guided Peripheral Nerve Blocks. Anesth Analg 2007; 105:1858-60, table of contents. [DOI: 10.1213/01.ane.0000286814.79988.0a] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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197
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Whitman J, Fronheiser MP, Ivancevich NM, Smith SW. Autonomous surgical robotics using 3-D ultrasound guidance: feasibility study. ULTRASONIC IMAGING 2007; 29:213-219. [PMID: 18481593 DOI: 10.1177/016173460702900402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The goal of this study was to test the feasibility of using a real-time 3D (RT3D) ultrasound scanner with a transthoracic matrix array transducer probe to guide an autonomous surgical robot. Employing a fiducial alignment mark on the transducer to orient the robot's frame of reference and using simple thresholding algorithms to segment the 3D images, we tested the accuracy of using the scanner to automatically direct a robot arm that touched two needle tips together within a water tank. RMS measurement error was 3.8% or 1.58 mm for an average path length of 41 mm. Using these same techniques, the autonomous robot also performed simulated needle biopsies of a cyst-like lesion in a tissue phantom. This feasibility study shows the potential for 3D ultrasound guidance of an autonomous surgical robot for simple interventional tasks, including lesion biopsy and foreign body removal.
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198
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Light ED, Mukundan S, Wolf PD, Smith SW. Real-time 3-d intracranial ultrasound with an endoscopic matrix array transducer. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1277-84. [PMID: 17478032 PMCID: PMC2755488 DOI: 10.1016/j.ultrasmedbio.2007.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 12/04/2006] [Accepted: 02/08/2007] [Indexed: 05/10/2023]
Abstract
A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting and 252 receive channels placed in a regular pattern in the array. The operating frequency is 4.5 MHz with a -6 dB bandwidth of 30%. The transducer is fabricated on a 10-layer flexible circuit from Microconnex (Snoqualmie, WA, USA). The purpose of this study is to evaluate the clinical feasibility of real-time 3-D intracranial ultrasound with this device. The Volumetrics Medical Imaging (Durham, NC, USA) 3-D scanner was used to obtain images in a canine model. A transcalvarial acoustic window was created under general anesthesia in the animal laboratory by placing a 10-mm burr hole in the high parietal calvarium of a 50-kg canine subject. The burr-hole was placed in a left parasagittal location to avoid the sagittal sinus, and the transducer was placed against the intact dura mater for ultrasound imaging. Images of the lateral ventricles were produced, including real-time 3-D guidance of a needle puncture of one ventricle. In a second canine subject, contrast-enhanced 3-D Doppler color flow images were made of the cerebral vessels including the complete Circle of Willis. Clinical applications may include real-time 3-D guidance of cerebrospinal fluid extraction from the lateral ventricles and bedside evaluation of critically ill patients where computed tomography and magnetic resonance imaging techniques are unavailable.
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Fronheiser MP, Smith SW. Analysis of a vibrating interventional device to improve 3-D colormark tracking. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2007; 54:1700-7. [PMID: 17703675 DOI: 10.1109/tuffc.2007.442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Ultrasound guidance of interventional devices during minimally invasive surgical procedures has been investigated by many researchers. Previously, we extended the methods used by the Colormark tracking system to several interventional devices using a real-time, three-dimensional (3-D) ultrasound system. These results showed that we needed to improve the efficiency and reliability of the tracking. In this paper, we describe an analytical model to predict the transverse vibrations along the length of an atrial septal puncture needle to enable design improvements of the tracking system. We assume the needle can be modeled as a hollow bar with a circular cross section with a fixed proximal end and a free distal end that is suspended vertically to ignore gravity effects. The initial results show an ability to predict the natural nodes and antinodes along the needle using the characteristic equation for free vibrations. Simulations show that applying a forcing function to the device at a natural antinode yields an order of magnitude larger vibration than when driving the device at a node. Pulsed wave spectral Doppler data was acquired along the distal portion of the needle in a water tank using a 2-D matrix array transesophageal echocardiography probe. This data was compared to simulations of forced vibrations from the model. These initial results suggest that the model is a good first order approximation of the vibrating device in a water tank. It is our belief that knowing the location of the natural nodes and antinodes will improve our ability to drive the device to ensure the vibrations at the proximal end will reach the tip of the device, which in turn should improve our ability to track the device in vivo.
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200
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Ramireddy A, Light ED, Smith SW. Ultrasound probe with integrated ECG lead: feasibility study. ULTRASONIC IMAGING 2007; 29:195-198. [PMID: 18092675 DOI: 10.1177/016173460702900305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We integrated electrocardiogram (ECG) leads onto the face of a cardiac ultrasound transducer and the exterior chassis of a simulated small, portable scanner to minimize the number of devices needed to collect cardiac information. Since the ECG leads were not placed on their standard locations, a precordial ECG was recorded.
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