- Email: [email protected]
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Abstracts Conclusion: Ultrasound is essential for preoperative assessment to plan for appropriate surgery.
DOPPLER ULTRASOUND OF HEAD AND NECK 1149 Carotid waveforms: Diagnostic patterns Gooding GAW, University of California, San Francisco (UCSF), United States of America Carotid and vertebral arteries are examined by ultrasound in three basic ways: (1) Grey Scale; (2) color Doppler and power Doppler; (3) Spectral analysis. Grey scale defines the morphology of the wall, the character and extent of plaque in the carotid artery and the thickness of intimal hyperplasia. Color Doppler may override and obscure some of these grey scale findings. Color Doppler depicts average velocity; it directs the operator to areas of turbulence, narrowing and stenosis. Color Doppler depends on an accurate angle of insonation, an angle of insonation between transducer and blood flow of less than 60 degrees. Greater angles introduce large errors in calculating velocity in cm/s. Power Doppler is angle independent; its use is to detect flow, often of low velocity, but the direction of flow or its nature, arterial or venous, is not distinguished. Duplex Doppler introduces not only a color Doppler image, but the spectral waveform. Peak systole and end diastole are the two parameters most commonly identified with spectral analysis, care taken to maintain an angle of insonation between transducer and vessel flow of 60 degrees or less. Waveform analysis adds immense value to the carotid and vertebral examination and pattern recognition is key to understanding the underlying pathology. These waveforms and their significance is the focus of this presentation. 1150 Vertebral, subclavian, and innominate artery ultrasound Gooding GAW, University of California, San Francisco (UCSF), United States of America Spectral waveforms are mainly of two types: (1) The waveform of organ flow. (2) The waveform of peripheral vascular flow. Organ flow, whether to the brain (ICA and vertebral arteries), the liver, spleen, gallbladder, testis, thyroid, lymph node etc., is typically low resistant flow, that is, flow does not reverse below baseline as a rule and diastolic flow is prominently above baseline throughout the diastolic component of the cycle. Peripheral vascular flow, which feeds a muscular bed, is highly resistant flow with a typical triphasic waveform. Velocity rises rapidly perpendicular to the baseline in systole, then falls dramatically below baseline in initial diastole, followed by a third forward thrust above baseline, well below the diastolic velocity that would be seen in organ flow. Peripheral arteries with triphasic flow are the subclavian artery, the arteries of the arms and legs, the iliac artery, the distal abdominal aorta and the external carotid artery. When a peripheral artery has spectral waveforms with an appearance of organ flow, it is abnormal. When the arteries feeding an organ have spectral waveforms that suggest peripheral vascular flow, it is abnormal. Specific waveforms in the vertebral, subclavian and innominate arteries reflect the pathologic processes involved. 1151 Use of B-flow in head and neck practice Karstrup S, Roskilde Hospital, Denmark B-flow is an US technique to visualise blood flow by means of B-mode imaging (gray scale). Thus, it is a non-Doppler technique. The technique (codescan) makes it possible to visualise echoes from the blood
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cells simultaneously with visualisation of the surrounding anatomical structures. There are several advantages of B-flow as compared to the colour Doppler techniques. (1) Practical advantages: it is easy to use, almost an “one button technique”. (2) Technical advantages: higher frame rate, higher dynamic rate, improved resolution, angle independent, no blooming artefacts and no aliasing. (3) Imaging advantages: visualisation of smaller vessels; visualisation of the true vessel lumen and internal morphology; simultaneous visualisation of venous (slow) and arterial (fast) blood flow. Disadvantages: B-flow has a limited depth penetration. The above advantages of B-flow are truly being reflected in the clinical examination of patients using high frequency probes. Thus, B-flow can give additional information when examining patients for carotid stenosis as it can show the relative reduction (degree of stenosis in percent) of the vessel calibre simultaneously with information of the internal condition ( i.e., plaques and ulcerations) of the vessel lumen. Another advantage of B-flow seems to be the possibility of visualising microcirculation in lymph nodes and organs (i.e., thyroid) and thus the technique opens up for a closer definition of the neo-angiogenesis. 1152 Color Doppler ultrasound of major salivary glands Chou Y-H, Dept. of Radiology, Veterans General Hospital, Taiwan Color Doppler ultrasound (CDU) is an important imaging technique for analyzing the vascularity of the salivary glands and, in conjunction with gray-scale imaging, can be used to characterize some pathologic conditions. Patients with Sjogren’s syndrome may or may not show parenchymal changes on high-resolution gray-scale ultrasound (US). Gray-scale changes mainly consist of a decrease of parenchymal echogenicity up to a total derangement of parenchymal texture, cyst-like ectasia of peripheral ducts, undefined margins and decreased volume of the gland. CDU show a higher number of color flow signals (CFS) in all heterogeneous glands than in normal glands. The hypervascularity is generally diffuse and can be subjectively graded (e.g., minimal, ⫾ or ⫹; intermediate, ⫹⫹; or profuse, ⫹⫹⫹ or ⫹⫹⫹⫹). Patients with salivary gland involvement in sarcoidosis had marked parotid swelling and a high grade of parenchymal heterogeneity on US.CDU shows diffuse hypervascularity of the glands similar to that seen in Sjogren’s disease. In chronic sclerosing sialadenitis the most common US appearances are the diffuse cirrhotic-like patterns. The involved gland shows prominent vascularity (⫹⫹–⫹⫹⫹) on CDU, with no mass effect or obvious displacement of the vessels. Both benign and malignant tumors have a higher grade of vascularity than the surrounding salivary parenchyma. Generally, malignant parotid tumors demonstrate a higher degree of tumor vascularization (profuse or intermediate) and higher peak systolic velocities (PSV) than benign tumors. Pleomorphic adenomas are oval hypoechoic lesions. Most had intermediate grade of vascularity and a peripheral basket-like pattern consisting of a fine vascular network surrounding the nodule. Spectral Doppler analysis (SDA) shows a wide range of resistivity index (RI) values (0.6 to 1.0), and a PSV below 50 cm s. Adenolymphomas are well-demarcated tumors, frequently associated with one or more cystic components and posterior enhancement. The larger the lesion, the more predominant the cystic portion. CDU depicts a hilar disposition of CFS with centrifugal distribution through one or more vascular pedicles in a relatively regular pattern. The RI and PSV are not significantly different from those in pleomorphic adenoma. Non-Hodgkin’s lymphomas appeared on US as single or occasionally multiple hypoechoic nodules in the parotid gland, similar to the pleomorphic adenomas, and have feeding and draining vessels that enter or leave and branch into the nodule through a centrally located pedicle, although a real hilum is not visible on gray-scale US. CDU shows profuse (graded ⫹⫹⫹ or ⫹⫹⫹⫹) vascularity. The accuracy of evaluating parotid tumors by gray-scale
DOPPLER ULTRASOUND OF HEAD AND NECK 1149 Carotid waveforms: Diagnostic patterns Gooding GAW, University of California, San Francisco (UCSF), United States of America Carotid and vertebral arteries are examined by ultrasound in three basic ways: (1) Grey Scale; (2) color Doppler and power Doppler; (3) Spectral analysis. Grey scale defines the morphology of the wall, the character and extent of plaque in the carotid artery and the thickness of intimal hyperplasia. Color Doppler may override and obscure some of these grey scale findings. Color Doppler depicts average velocity; it directs the operator to areas of turbulence, narrowing and stenosis. Color Doppler depends on an accurate angle of insonation, an angle of insonation between transducer and blood flow of less than 60 degrees. Greater angles introduce large errors in calculating velocity in cm/s. Power Doppler is angle independent; its use is to detect flow, often of low velocity, but the direction of flow or its nature, arterial or venous, is not distinguished. Duplex Doppler introduces not only a color Doppler image, but the spectral waveform. Peak systole and end diastole are the two parameters most commonly identified with spectral analysis, care taken to maintain an angle of insonation between transducer and vessel flow of 60 degrees or less. Waveform analysis adds immense value to the carotid and vertebral examination and pattern recognition is key to understanding the underlying pathology. These waveforms and their significance is the focus of this presentation. 1150 Vertebral, subclavian, and innominate artery ultrasound Gooding GAW, University of California, San Francisco (UCSF), United States of America Spectral waveforms are mainly of two types: (1) The waveform of organ flow. (2) The waveform of peripheral vascular flow. Organ flow, whether to the brain (ICA and vertebral arteries), the liver, spleen, gallbladder, testis, thyroid, lymph node etc., is typically low resistant flow, that is, flow does not reverse below baseline as a rule and diastolic flow is prominently above baseline throughout the diastolic component of the cycle. Peripheral vascular flow, which feeds a muscular bed, is highly resistant flow with a typical triphasic waveform. Velocity rises rapidly perpendicular to the baseline in systole, then falls dramatically below baseline in initial diastole, followed by a third forward thrust above baseline, well below the diastolic velocity that would be seen in organ flow. Peripheral arteries with triphasic flow are the subclavian artery, the arteries of the arms and legs, the iliac artery, the distal abdominal aorta and the external carotid artery. When a peripheral artery has spectral waveforms with an appearance of organ flow, it is abnormal. When the arteries feeding an organ have spectral waveforms that suggest peripheral vascular flow, it is abnormal. Specific waveforms in the vertebral, subclavian and innominate arteries reflect the pathologic processes involved. 1151 Use of B-flow in head and neck practice Karstrup S, Roskilde Hospital, Denmark B-flow is an US technique to visualise blood flow by means of B-mode imaging (gray scale). Thus, it is a non-Doppler technique. The technique (codescan) makes it possible to visualise echoes from the blood
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cells simultaneously with visualisation of the surrounding anatomical structures. There are several advantages of B-flow as compared to the colour Doppler techniques. (1) Practical advantages: it is easy to use, almost an “one button technique”. (2) Technical advantages: higher frame rate, higher dynamic rate, improved resolution, angle independent, no blooming artefacts and no aliasing. (3) Imaging advantages: visualisation of smaller vessels; visualisation of the true vessel lumen and internal morphology; simultaneous visualisation of venous (slow) and arterial (fast) blood flow. Disadvantages: B-flow has a limited depth penetration. The above advantages of B-flow are truly being reflected in the clinical examination of patients using high frequency probes. Thus, B-flow can give additional information when examining patients for carotid stenosis as it can show the relative reduction (degree of stenosis in percent) of the vessel calibre simultaneously with information of the internal condition ( i.e., plaques and ulcerations) of the vessel lumen. Another advantage of B-flow seems to be the possibility of visualising microcirculation in lymph nodes and organs (i.e., thyroid) and thus the technique opens up for a closer definition of the neo-angiogenesis. 1152 Color Doppler ultrasound of major salivary glands Chou Y-H, Dept. of Radiology, Veterans General Hospital, Taiwan Color Doppler ultrasound (CDU) is an important imaging technique for analyzing the vascularity of the salivary glands and, in conjunction with gray-scale imaging, can be used to characterize some pathologic conditions. Patients with Sjogren’s syndrome may or may not show parenchymal changes on high-resolution gray-scale ultrasound (US). Gray-scale changes mainly consist of a decrease of parenchymal echogenicity up to a total derangement of parenchymal texture, cyst-like ectasia of peripheral ducts, undefined margins and decreased volume of the gland. CDU show a higher number of color flow signals (CFS) in all heterogeneous glands than in normal glands. The hypervascularity is generally diffuse and can be subjectively graded (e.g., minimal, ⫾ or ⫹; intermediate, ⫹⫹; or profuse, ⫹⫹⫹ or ⫹⫹⫹⫹). Patients with salivary gland involvement in sarcoidosis had marked parotid swelling and a high grade of parenchymal heterogeneity on US.CDU shows diffuse hypervascularity of the glands similar to that seen in Sjogren’s disease. In chronic sclerosing sialadenitis the most common US appearances are the diffuse cirrhotic-like patterns. The involved gland shows prominent vascularity (⫹⫹–⫹⫹⫹) on CDU, with no mass effect or obvious displacement of the vessels. Both benign and malignant tumors have a higher grade of vascularity than the surrounding salivary parenchyma. Generally, malignant parotid tumors demonstrate a higher degree of tumor vascularization (profuse or intermediate) and higher peak systolic velocities (PSV) than benign tumors. Pleomorphic adenomas are oval hypoechoic lesions. Most had intermediate grade of vascularity and a peripheral basket-like pattern consisting of a fine vascular network surrounding the nodule. Spectral Doppler analysis (SDA) shows a wide range of resistivity index (RI) values (0.6 to 1.0), and a PSV below 50 cm s. Adenolymphomas are well-demarcated tumors, frequently associated with one or more cystic components and posterior enhancement. The larger the lesion, the more predominant the cystic portion. CDU depicts a hilar disposition of CFS with centrifugal distribution through one or more vascular pedicles in a relatively regular pattern. The RI and PSV are not significantly different from those in pleomorphic adenoma. Non-Hodgkin’s lymphomas appeared on US as single or occasionally multiple hypoechoic nodules in the parotid gland, similar to the pleomorphic adenomas, and have feeding and draining vessels that enter or leave and branch into the nodule through a centrally located pedicle, although a real hilum is not visible on gray-scale US. CDU shows profuse (graded ⫹⫹⫹ or ⫹⫹⫹⫹) vascularity. The accuracy of evaluating parotid tumors by gray-scale