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Abstract No. 48: Doppler Vibrometry: Assessment of Arterial Stenoses Using Perivascular Tissue Vibrations without Lumen Visualization
was given in all patients. Periinterventionally, heparin infusions were administered at therapeutical dosage in 20 procedures. Additionally to suction embolectomy, thrombolytics (200.000 to 800.000 I.U. of UK) were administered locally in 24 procedures. The access sutures were tied at completion of the intervention after sheath withdrawal. RESULTS: Immediate angiographic success was achieved in all patients. The fluoroscopy time was 25.7 ⫾ 15.6 Min. Suture-mediated hemostasis was insufficient in five procedures (14%) requiring compression (n⫽3), stent-grafting (n⫽1) or surgical closure (n⫽1). There were no other major access site complications. Calf fasciotomies had been made in 17% (n⫽6) of the procedures. At 30 days, mortality was 6% (n⫽2, MOF). At 3 months, reocclusions had occurred after 17% of the procedures and four patients (13%) had undergone BK-amputation. CONCLUSION: Femoral access preclosing is an efficacious and safe adjunct to suction thrombectomy in acute lower extremity arterial occlusions. 2:06 PM
Abstract No. 48
Doppler Vibrometry: Assessment of Arterial Stenoses Using Perivascular Tissue Vibrations without Lumen Visualization. S. Sikdar,1 S.S. Vaidya,2 M.K. Dighe,2 O. Kolokythas,2 K.W. Beach,3 R.T. Andrews,2 Y. Kim;1 1Department of Bioengineering, University of Washington, Seattle, WA; 2 Department of Radiology, University of Washington, Seattle, WA; 3Department of Surgery, University of Washington, Seattle, WA PURPOSE: Audio-frequency tissue vibrations (bruits) are caused by turbulent flow downstream of an arterial stenosis and can be located and quantified using a new method called Doppler vibrometry. The objective of this pilot study was to correlate vibration characteristics (frequency, duration, amplitude) with stenosis severity determined by catheter angiography. MATERIALS AND METHODS: 11 patients (5 women) clinically indicated for abdominal or pelvic arteriography were recruited for an investigational ultrasound examination following informed consent procedures approved by the University of Wahsington Institutional Review Board. A customized ultrasound system was used to acquire raw ultrasound echoes from tissue regions proximal, mid and distal to renal, hepatic, iliac, and superior mesenteric arterial stenoses prior to arteriography. These were processed using previously-developed phase demodulation methods to quantify the vibration frequency, amplitude and duration. The minimum lumen diameter and the pre- and post-stenotic lumen diameters were quantified from angiograms. One patient with a hepatic stenosis did not yield measurable vibrometry data due to significant bowel gas. RESULTS: Stenoses (range 61-89%) were angiographically measured in the 4 renal, 3 hepatic 2 iliac, and 1 superior mesenteric arteries yielding vibrometry data. For these 10 lesions, the vibration frequency was higher for greater percent stenosis {Pearson’s r⫽0.71 (P⫽0.01)} and was higher for smaller minimum lumen diameter {r⫽0.56 (P ⬍ 0.05)}. The vibration duration increased for greater percent stenosis {r⫽0.75 (P⫽0.006)}. The vibration amplitude was highest for stenoses of intermediate severity (75-80%) and was lower for less severe and more severe stenoses as expected: less severe stenoses yield lower vibration power because of S20
lower pressure drop; more severe stenoses yield lower vibration power because of lower flow rate. CONCLUSION: Preliminary results indicate that the frequency and duration of tissue vibrations may be used to quantitatively estimate the severity of arterial stenoses. Doppler vibrometry is complementary to conventional duplex sonography and does not require visualization of the arterial lumen. 2:18 PM
Abstract No. 49
Effects of Using Nitroglycerin for Diagnostic Accuracy of the ECG-Gated 64-MDCT Coronary Angiography. S.H. Kwon,1 J.H. Oh,2 B.R. Park,3 D.W. Sung,4 S.J. Kim,5 K.S. Kim,6 M.G. Kim,7 S.J. Hwang;8 1Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 2Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 3Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 4Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 5Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 6 Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 7Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 8Kyung Hee University Hospital, Department of Medicine, Seoul, Korea PURPOSE: To compare the diagnostic accuracy of ECGgated 64-MDCT coronary angiography between sublingual nitroglycerin (NTG)-receiving group and non-receiving group. MATERIALS AND METHODS: Between December 2006 and March 2007, 65 patients (M : F ⫽ 34 :31, mean age⫽61.6 ⫾ 9.4) with suspected coronary artery disease underwent ECG-gated 64-MDCT coronary angiography (CTCA) and conventional coronary angiography (CAG). Patients with the heart rates above 65 bpm received oral -blockers 1 hour before CT scan. 34 patients were given of a sublingual NTG (0.6 mg) 1 minute before the CT scan (NTG group), and the others were not (non-NTG group). The optimal reconstruction interval was chosen from different phase settings (range 30%-75% of RR interval). 2 radiologists assessed the significant stenosis (ⱖ 50%) of coronary artery according to the modified 16 segments model of the American Heart Association. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were calculated on a persegment basis in comparison with the CAG as a gold standard. RESULTS: Of 990 segments, 15 were excluded due to bad quality [severe calcification (n⫽5), artifact due to respiration (n⫽3), cardiac motion (n⫽3), adjacent contrast filled structure (n⫽2) and air in contrast (n⫽2)], and 975 were evaluated. There were 510 segments in NTG group and 465 in non-NTG group. There were no statistically significant differences in age, sex, heart rate, BP, interval between CTCA and CAG (19.4 ⫾ 18.8 days). The sensitivity, specificity, PPV, NPV, diagnostic accuracy in NTG group were 91.5%, 99.1%, 91.5%, 99.1% and 98.4% respectively, which were significantly higher than 74.2%, 96.3%, 59.0%, 98.1% and 94.8% of the non-NTG group (p ⬍ 0.05). CONCLUSION: Using sublingual NTG improves diagnostic accuracy of ECG-gated 64-MDCT coronary angiography for the coronary artery stenosis, as compared with non-NTG group.
Abstract No. 48
Doppler Vibrometry: Assessment of Arterial Stenoses Using Perivascular Tissue Vibrations without Lumen Visualization. S. Sikdar,1 S.S. Vaidya,2 M.K. Dighe,2 O. Kolokythas,2 K.W. Beach,3 R.T. Andrews,2 Y. Kim;1 1Department of Bioengineering, University of Washington, Seattle, WA; 2 Department of Radiology, University of Washington, Seattle, WA; 3Department of Surgery, University of Washington, Seattle, WA PURPOSE: Audio-frequency tissue vibrations (bruits) are caused by turbulent flow downstream of an arterial stenosis and can be located and quantified using a new method called Doppler vibrometry. The objective of this pilot study was to correlate vibration characteristics (frequency, duration, amplitude) with stenosis severity determined by catheter angiography. MATERIALS AND METHODS: 11 patients (5 women) clinically indicated for abdominal or pelvic arteriography were recruited for an investigational ultrasound examination following informed consent procedures approved by the University of Wahsington Institutional Review Board. A customized ultrasound system was used to acquire raw ultrasound echoes from tissue regions proximal, mid and distal to renal, hepatic, iliac, and superior mesenteric arterial stenoses prior to arteriography. These were processed using previously-developed phase demodulation methods to quantify the vibration frequency, amplitude and duration. The minimum lumen diameter and the pre- and post-stenotic lumen diameters were quantified from angiograms. One patient with a hepatic stenosis did not yield measurable vibrometry data due to significant bowel gas. RESULTS: Stenoses (range 61-89%) were angiographically measured in the 4 renal, 3 hepatic 2 iliac, and 1 superior mesenteric arteries yielding vibrometry data. For these 10 lesions, the vibration frequency was higher for greater percent stenosis {Pearson’s r⫽0.71 (P⫽0.01)} and was higher for smaller minimum lumen diameter {r⫽0.56 (P ⬍ 0.05)}. The vibration duration increased for greater percent stenosis {r⫽0.75 (P⫽0.006)}. The vibration amplitude was highest for stenoses of intermediate severity (75-80%) and was lower for less severe and more severe stenoses as expected: less severe stenoses yield lower vibration power because of S20
lower pressure drop; more severe stenoses yield lower vibration power because of lower flow rate. CONCLUSION: Preliminary results indicate that the frequency and duration of tissue vibrations may be used to quantitatively estimate the severity of arterial stenoses. Doppler vibrometry is complementary to conventional duplex sonography and does not require visualization of the arterial lumen. 2:18 PM
Abstract No. 49
Effects of Using Nitroglycerin for Diagnostic Accuracy of the ECG-Gated 64-MDCT Coronary Angiography. S.H. Kwon,1 J.H. Oh,2 B.R. Park,3 D.W. Sung,4 S.J. Kim,5 K.S. Kim,6 M.G. Kim,7 S.J. Hwang;8 1Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 2Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 3Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 4Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul, Korea; 5Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 6 Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 7Kyung Hee University Hospital, Department of Medicine, Seoul, Korea; 8Kyung Hee University Hospital, Department of Medicine, Seoul, Korea PURPOSE: To compare the diagnostic accuracy of ECGgated 64-MDCT coronary angiography between sublingual nitroglycerin (NTG)-receiving group and non-receiving group. MATERIALS AND METHODS: Between December 2006 and March 2007, 65 patients (M : F ⫽ 34 :31, mean age⫽61.6 ⫾ 9.4) with suspected coronary artery disease underwent ECG-gated 64-MDCT coronary angiography (CTCA) and conventional coronary angiography (CAG). Patients with the heart rates above 65 bpm received oral -blockers 1 hour before CT scan. 34 patients were given of a sublingual NTG (0.6 mg) 1 minute before the CT scan (NTG group), and the others were not (non-NTG group). The optimal reconstruction interval was chosen from different phase settings (range 30%-75% of RR interval). 2 radiologists assessed the significant stenosis (ⱖ 50%) of coronary artery according to the modified 16 segments model of the American Heart Association. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were calculated on a persegment basis in comparison with the CAG as a gold standard. RESULTS: Of 990 segments, 15 were excluded due to bad quality [severe calcification (n⫽5), artifact due to respiration (n⫽3), cardiac motion (n⫽3), adjacent contrast filled structure (n⫽2) and air in contrast (n⫽2)], and 975 were evaluated. There were 510 segments in NTG group and 465 in non-NTG group. There were no statistically significant differences in age, sex, heart rate, BP, interval between CTCA and CAG (19.4 ⫾ 18.8 days). The sensitivity, specificity, PPV, NPV, diagnostic accuracy in NTG group were 91.5%, 99.1%, 91.5%, 99.1% and 98.4% respectively, which were significantly higher than 74.2%, 96.3%, 59.0%, 98.1% and 94.8% of the non-NTG group (p ⬍ 0.05). CONCLUSION: Using sublingual NTG improves diagnostic accuracy of ECG-gated 64-MDCT coronary angiography for the coronary artery stenosis, as compared with non-NTG group.