- Email: [email protected]
CTA
Friday, March 26, 2004 8:00 a.m.-9:30 a.m.
Coordinator/Moderator: Tony P. Smith, MD
Objectives: 1. integrate information regarding appropriate patient
screening and selection for carotid stenting. 2. Discuss complications of carotid stenting highlighting avoidance and treatmenl. 3. Relate information regarding choices of latest equipment including problems encountered.
Panelists: Patient Selection: It's Not What You Do-It's Who You Do
Tony P Smith, MD Duke University Medical Center Durham, NC Tools of the Trade: What Works and What Does Not Michael H. Wholey, MD University of Texas Health Science Center-San Antonio San AntoniO, IX Complications: What I've Learned and How to Avoid Them Gustav R. Eles, MD Pittsburgh Cardiac & Vascular Assoc., PC Pittsburgh, PA
Coordinator/Moderator: Matthew S. johnson, MD
Objectives: 1. Compare the technical and practical aspects of MRA
and erA. 2. Discuss the CUlTen! status, promise, and limitations of MRA and CTA in the evaluation of the carotid arteries, renal arteries, of the aorta, iliac arteries, and arteries of the lower extremity. 8:00 a.m. Carotid MRA/CTA jay Cinnamon, MD Emory University Atlanta, GA 8:20 a.m. Renal MRA!CTA jonas Rydberg, MD [ndiana University School of Medicine Indianapolis, IN
Renal vascular imaging was previously done with conventional angiographic technique. It also had its focus
on arterial imaging since venous evaluation was difficult to perform and rarely requested. Today renal vascular imaging is done with er and MR and may comprise both the arteries and the veins. The arterial evaluations can be divided into two categories: • Incidenta l evaluations • Dedicated evaluations The incidental evaluations refer to situations where the renal arteries have to be evaluated as part of a larger imaging scope such as: • Abdominal aortic aneurysm • Abdominal aortic dissection • Abdominal aortic stentgraft surgelY follow-up • Radiological work-up related to acute trauma. The dedicated evaluations refer to situations where the renal arteries are in sole focus such as: • Suspicion for renal artelY hypertension (stenosis or fibromu scular dysplasia , FMD) • Renal artery stentgrafl surgery follow-up • Preoperative evaluation of living renal donors Renal venous evaluation is mainly related to the preoperative work-up of potential living renal donors. Evaluation of renal artery stenosis has been done with CT on a routine basis ever since helical er was introdu ced almost 15 years ago. er has replaced arteriography for evaluating renal vasculature before living renal donations. Multichannel er has significantly improved the ability to show pathological changes in the main renal arteries as well as raised the ability to depict branching main renal arteries and small accessory renal arteries. Efforts have also been done with er in the evaluation of fibromuscul ar dysplasia. Over the last years there has been a fast development of detailed and fast MRI scanning techniques of the renal vasculature. Non-enhanced 2D time-of-flight protocols have been replaced by gadolinium enhanced 3D gradienl echo protocols. The current state-of-the-art MRI scanners equipped with improved gradient strengths allow for high resolution datasets acquired during one breath hold. Contrast Media Administration The scan times for both CTA and MRA exams are currently between 10 and 30 seconds long. The sholt scan times raises the demand for proper timing with the contrast media injection. If the injection is started too early the re is a risk for inadequate opacification of the vessels and if the scanning is done too late it may result in venous contamination of the arterial images. Proper timing can be acquired for both CTA and j\1RA in three ways:
Empirical Timing The "empirical timing" is really a matter of guessing the appropriate delay from injection start to maximum contrast enhancement in the target vessels. For young patients with good cardiovascular status the delay time for arterial evaluation is around 20 seconds and for venou s
P37
evaluation around 1 minute. For patients with decreased cardiovascular function the delay time for the arterial phase may have to be lengthened to 30 seconds or more. When the "empirical timing" technique is applied a larger amount of contrast media (i.e. longer bolus train) has to be utilized in order to be certain that contrast media will fill out the vessels when the scanning is done. Test bolus technique. By injecting a small amount of contrast media and then scan continuously at the level of the renal arteries the individual transit time to the target vessels for each patient can be calculated. This will allow for reduction in the total amount of contrast media utilized without risk of loosing the correct timing for the main exam. Software Triggering By using automated triggering software the total contrast media amount can be injected initially, without having to do a test bolus. Continuous scanning at a predefined localization is done. When a certain Hounsfield unit (CT) or a certain signal intensity level (MR) is reached within the aorta the scanning starts automatically. The automated software triggering technique is becoming standard on most CT scanners but many MR protocols are based on test bolus utilization. CT Angiography In most institutions where CT arteriography is done on a routine basis multichannel CT is used (synonyms for multichannel CT are "multislice CT" and "multi-detector row CT"). The scanners may be equipped with 2, 4, 8,10 or 16 channel capacity. With higher number of channels more slices can be acquired per second and the scanning can be performed faster. An increase in number of channels usually allows for acquisition of thinner slice. Typical scan time for renal altery evaluations are 10-15 seconds yielding a slice thickness less than 1 mm. MR Angiography State-of-the-art MR scanners have fast gradient systems that allow for fast 3D T1 weighted gradient echo acquisition techniques. The scan time can be limited to 20-30 seconds thereby allowing "breath-hold scanning". The typical slice thickness for MR angiography is thicker than the one for CT angiography. cr and MR: Postprocessing The source images from both modalities are always sent to a workstation for postprocessing. The postprocessing techniques for CT and MR are basically the same and are either 2D reformats or 3D reconstructions. Reformats (2D) may be coronal, coronal oblique, sagittal or radial. The 3D techniques are usually Maximum Intensity Projection (MIP) and Volume rendering (VR). The choice of postprocessing technique may vary due to individual preference. The MIP reconstructions usually take longer time to create than VR images. With VR there is a higher risk of missing small vessels. The current workstations allow for very fast postprocessing times. On state-of-the-
P38
art workstations the time required for postprocessing is about 10-30 minutes. The time needed is often related to the skill level of the person doing the postprocessing. The postprocessed images are helpful for the diagnostic work as well for the purpose of demonstrating anatomy and abnormalities for referring clinicians. Pro and Con cr-angiography Pro: Robust technique Very high spatial resolution Short examination times Con: Vessel wall calcifications limiting evaluation of stenosis Risk for contrast media induced nephropathy Ionizing radiation Pro and Con MR-angiography Pro: Breath hold scanning High spatial resolution Fast image postprocessing Con: Demand on patient to keep still during scanning Inability to show calcium Artifacts caused by turbulent blood flow Risk for overestimating vessel stenosis Contraindicated for certain stent grafts Living Renal Donors and Renal Venous Evaluation Laparoscopic living renal donor nephrectomy, which was introduced in 1995, has created raised demands on the evaluation of the venous system. Without accurate pre-operative venous mapping, intra-operative venous injury may occur more often, increasing blood loss and increasing the frequency of conversion of a laparoscopic nephrectomy to open nephrectomy. The venous "road mapping" before laparoscopic nephrectomy has become possible with both CT and MR. Both methods can depict the renal veins, including variants. Only CT has so far been able to depict the smallest retroperitoneal contributories. Summary During the last 3-4 years there has been a fast development of CTA and MRA. Multichannel CT and 3D MR allow for detailed analysis of renal vasculature, both arterial and venous. For work-up of renal artery hypertension and preoperative for abdominal aortic aneurysms CT and MR show equally good results . For evaluation of renal vasculature in ER patients and in patients with metallic stentgrafts CT is the method of choice. The role for conventional diagnostic angiography has become very limited.
References
10:30 a.m.-12:00 p.m.
l. Mallouhi A, Schocke M, Judmaier et al. 3D MR an-
giography of renal arteries: Comparison of volume rendering and maximum intensity projection algorithms. Radiology 2002;223:509-516
:-··"i;";'l'J-,...,,,"
":jj
2. Israel G. Lee V, Edye 1VI et a l. Comprehensive MR imaging in the preoperative evaluation of living donor candidates for laparoscopic nephrectomy: Initial experience. Radiology 2002;225:427-432 3. Kawamoto S, Montgomery R, Lawler L et al. Multidetector cr angiography for preoperative evaluation of living laparoscopic kidney donors. AJR 2003; 180: 1633-1638 4. Hussain S, Kock M, Ijzermans et al. MR imaging: A "one-stop-shop" modality for preoperative evaluation of potential living kidney donors. Radiographics 2003;23:505-520 5. Willman ] , Wildermuth S, Pfammatter et al. Aorroiliac and renal arteries: Prospective intraindividual comparison of contrast-enhanced three-dimensional MR angiography and multi-detector row cr angiography. Radiology 2003;226:798-811 6. Van Hoe L, De Jaegere T, Bosmans H. Breath-hold contrast-enhanced three-dimensional MR angiography of the abdomen: Time resolved imaging versus single-phase imaging. Radiology 2000;214:149-156 7. N Rofsky and M Adelman. MR angiography in the eva luation of atherosclerotic peripheral vascular disease. Radiology 2000;214:325-338 8. Earls], DeSena Sa nd Bluemke D. Gadolinium-enhanced three-dimensional MR angiography of the entire aOl1a and iliac arteries with dynamic manual table translation. Radiology 1998;209:844-849 9. Rydberg], Kopecky KK, Shalhav Al e( al. Evaluation of Prospective Living Renal Donors for Laparoscopic Nephrectomy with Multisection CT: The Marriage of Minimally Invasive Imaging with Minimally Invasive Surgery. RadioGraphics 2001 ;2 1:223S-236S 10. Berg M, Maninen H, Vanninen el al. Assessment of renal artery stenosis with cr angiography: usefulness of multiplanar reformation, quantitative stenosis measurements, and densitometric analysis of renal parenchymal enhancement as adjuncts to MIP film reading. ]CAT 1998;22:533-540
8:46 a.m. CTA of the Aorta and Lower Extremities GeoffelY Rubin, MD Stanford University School of Medicine Stanford, CA
9:09 a.m. MRA of the Aorta and Lower Extremities Martin R. Prince, MD, PhD Camel! Medical University New York, NY
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nsufficien~y: -
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iVloderator: Rodney D. Raabe, MD
Objectives: l. Distinguish trends in percutaneous vein ablatio n.
2. Examine strategies for clinical assessment of patients with vein insufficiency. 3. Describe available devices and ancillary techniques_ 10:30 a.m. Welcome Brian F. Stainken, MD Roger Williams Medical Center Providence, RI 10:35 a.m. Office Based Workup Neil M. Khilnani, MD Cornel! Vascular New York, NY History A directed problem specific patient history is obtained to understand the nature of the problems that e ncouraged the patient to seek a medical opinion or treatment. A standard medical history is supplemented with specific questions for patients with varicose and spider veins: 1. The presence of associated symptoms. Symptoms which are typically associated with varicose veins include pruritis, leg pain or heaviness, pal1icularly al the end of a day after prolonged standing, leg fatigue , restless or night cramps. One should quely abo ul the presence a history of any skin changes as well.
2. Previous treatments which the patient has undergone including surgery, endovenous and sclerotherapy. The response to each of these treatment and any complications should be speCifically addressed. The use of graduated support stockings, their effect on symptoms and how the patients tolerated this intervention should also be discussed with the patient. 3. Whether the patient has had any superfiCial or deep venous thrombosis is also an important pan of the history; this may help identify a patient with varicose veins secondary to deep vein occlusion or a patient with a hyper-coagulability syndrome. 4. Hormone medications or periods of hormonal flux , including the perimenopausal period can predispose to pigmentation following Sclerotherapy and shou ld be asked about 5. Concomitant disease may predispose some patients to complication or failure. These include peripheral arterial disease which can preclude the use of graduated compression hose.
P39
Coordinator/Moderator: Tony P. Smith, MD
Objectives: 1. integrate information regarding appropriate patient
screening and selection for carotid stenting. 2. Discuss complications of carotid stenting highlighting avoidance and treatmenl. 3. Relate information regarding choices of latest equipment including problems encountered.
Panelists: Patient Selection: It's Not What You Do-It's Who You Do
Tony P Smith, MD Duke University Medical Center Durham, NC Tools of the Trade: What Works and What Does Not Michael H. Wholey, MD University of Texas Health Science Center-San Antonio San AntoniO, IX Complications: What I've Learned and How to Avoid Them Gustav R. Eles, MD Pittsburgh Cardiac & Vascular Assoc., PC Pittsburgh, PA
Coordinator/Moderator: Matthew S. johnson, MD
Objectives: 1. Compare the technical and practical aspects of MRA
and erA. 2. Discuss the CUlTen! status, promise, and limitations of MRA and CTA in the evaluation of the carotid arteries, renal arteries, of the aorta, iliac arteries, and arteries of the lower extremity. 8:00 a.m. Carotid MRA/CTA jay Cinnamon, MD Emory University Atlanta, GA 8:20 a.m. Renal MRA!CTA jonas Rydberg, MD [ndiana University School of Medicine Indianapolis, IN
Renal vascular imaging was previously done with conventional angiographic technique. It also had its focus
on arterial imaging since venous evaluation was difficult to perform and rarely requested. Today renal vascular imaging is done with er and MR and may comprise both the arteries and the veins. The arterial evaluations can be divided into two categories: • Incidenta l evaluations • Dedicated evaluations The incidental evaluations refer to situations where the renal arteries have to be evaluated as part of a larger imaging scope such as: • Abdominal aortic aneurysm • Abdominal aortic dissection • Abdominal aortic stentgraft surgelY follow-up • Radiological work-up related to acute trauma. The dedicated evaluations refer to situations where the renal arteries are in sole focus such as: • Suspicion for renal artelY hypertension (stenosis or fibromu scular dysplasia , FMD) • Renal artery stentgrafl surgery follow-up • Preoperative evaluation of living renal donors Renal venous evaluation is mainly related to the preoperative work-up of potential living renal donors. Evaluation of renal artery stenosis has been done with CT on a routine basis ever since helical er was introdu ced almost 15 years ago. er has replaced arteriography for evaluating renal vasculature before living renal donations. Multichannel er has significantly improved the ability to show pathological changes in the main renal arteries as well as raised the ability to depict branching main renal arteries and small accessory renal arteries. Efforts have also been done with er in the evaluation of fibromuscul ar dysplasia. Over the last years there has been a fast development of detailed and fast MRI scanning techniques of the renal vasculature. Non-enhanced 2D time-of-flight protocols have been replaced by gadolinium enhanced 3D gradienl echo protocols. The current state-of-the-art MRI scanners equipped with improved gradient strengths allow for high resolution datasets acquired during one breath hold. Contrast Media Administration The scan times for both CTA and MRA exams are currently between 10 and 30 seconds long. The sholt scan times raises the demand for proper timing with the contrast media injection. If the injection is started too early the re is a risk for inadequate opacification of the vessels and if the scanning is done too late it may result in venous contamination of the arterial images. Proper timing can be acquired for both CTA and j\1RA in three ways:
Empirical Timing The "empirical timing" is really a matter of guessing the appropriate delay from injection start to maximum contrast enhancement in the target vessels. For young patients with good cardiovascular status the delay time for arterial evaluation is around 20 seconds and for venou s
P37
evaluation around 1 minute. For patients with decreased cardiovascular function the delay time for the arterial phase may have to be lengthened to 30 seconds or more. When the "empirical timing" technique is applied a larger amount of contrast media (i.e. longer bolus train) has to be utilized in order to be certain that contrast media will fill out the vessels when the scanning is done. Test bolus technique. By injecting a small amount of contrast media and then scan continuously at the level of the renal arteries the individual transit time to the target vessels for each patient can be calculated. This will allow for reduction in the total amount of contrast media utilized without risk of loosing the correct timing for the main exam. Software Triggering By using automated triggering software the total contrast media amount can be injected initially, without having to do a test bolus. Continuous scanning at a predefined localization is done. When a certain Hounsfield unit (CT) or a certain signal intensity level (MR) is reached within the aorta the scanning starts automatically. The automated software triggering technique is becoming standard on most CT scanners but many MR protocols are based on test bolus utilization. CT Angiography In most institutions where CT arteriography is done on a routine basis multichannel CT is used (synonyms for multichannel CT are "multislice CT" and "multi-detector row CT"). The scanners may be equipped with 2, 4, 8,10 or 16 channel capacity. With higher number of channels more slices can be acquired per second and the scanning can be performed faster. An increase in number of channels usually allows for acquisition of thinner slice. Typical scan time for renal altery evaluations are 10-15 seconds yielding a slice thickness less than 1 mm. MR Angiography State-of-the-art MR scanners have fast gradient systems that allow for fast 3D T1 weighted gradient echo acquisition techniques. The scan time can be limited to 20-30 seconds thereby allowing "breath-hold scanning". The typical slice thickness for MR angiography is thicker than the one for CT angiography. cr and MR: Postprocessing The source images from both modalities are always sent to a workstation for postprocessing. The postprocessing techniques for CT and MR are basically the same and are either 2D reformats or 3D reconstructions. Reformats (2D) may be coronal, coronal oblique, sagittal or radial. The 3D techniques are usually Maximum Intensity Projection (MIP) and Volume rendering (VR). The choice of postprocessing technique may vary due to individual preference. The MIP reconstructions usually take longer time to create than VR images. With VR there is a higher risk of missing small vessels. The current workstations allow for very fast postprocessing times. On state-of-the-
P38
art workstations the time required for postprocessing is about 10-30 minutes. The time needed is often related to the skill level of the person doing the postprocessing. The postprocessed images are helpful for the diagnostic work as well for the purpose of demonstrating anatomy and abnormalities for referring clinicians. Pro and Con cr-angiography Pro: Robust technique Very high spatial resolution Short examination times Con: Vessel wall calcifications limiting evaluation of stenosis Risk for contrast media induced nephropathy Ionizing radiation Pro and Con MR-angiography Pro: Breath hold scanning High spatial resolution Fast image postprocessing Con: Demand on patient to keep still during scanning Inability to show calcium Artifacts caused by turbulent blood flow Risk for overestimating vessel stenosis Contraindicated for certain stent grafts Living Renal Donors and Renal Venous Evaluation Laparoscopic living renal donor nephrectomy, which was introduced in 1995, has created raised demands on the evaluation of the venous system. Without accurate pre-operative venous mapping, intra-operative venous injury may occur more often, increasing blood loss and increasing the frequency of conversion of a laparoscopic nephrectomy to open nephrectomy. The venous "road mapping" before laparoscopic nephrectomy has become possible with both CT and MR. Both methods can depict the renal veins, including variants. Only CT has so far been able to depict the smallest retroperitoneal contributories. Summary During the last 3-4 years there has been a fast development of CTA and MRA. Multichannel CT and 3D MR allow for detailed analysis of renal vasculature, both arterial and venous. For work-up of renal artery hypertension and preoperative for abdominal aortic aneurysms CT and MR show equally good results . For evaluation of renal vasculature in ER patients and in patients with metallic stentgrafts CT is the method of choice. The role for conventional diagnostic angiography has become very limited.
References
10:30 a.m.-12:00 p.m.
l. Mallouhi A, Schocke M, Judmaier et al. 3D MR an-
giography of renal arteries: Comparison of volume rendering and maximum intensity projection algorithms. Radiology 2002;223:509-516
:-··"i;";'l'J-,...,,,"
":jj
2. Israel G. Lee V, Edye 1VI et a l. Comprehensive MR imaging in the preoperative evaluation of living donor candidates for laparoscopic nephrectomy: Initial experience. Radiology 2002;225:427-432 3. Kawamoto S, Montgomery R, Lawler L et al. Multidetector cr angiography for preoperative evaluation of living laparoscopic kidney donors. AJR 2003; 180: 1633-1638 4. Hussain S, Kock M, Ijzermans et al. MR imaging: A "one-stop-shop" modality for preoperative evaluation of potential living kidney donors. Radiographics 2003;23:505-520 5. Willman ] , Wildermuth S, Pfammatter et al. Aorroiliac and renal arteries: Prospective intraindividual comparison of contrast-enhanced three-dimensional MR angiography and multi-detector row cr angiography. Radiology 2003;226:798-811 6. Van Hoe L, De Jaegere T, Bosmans H. Breath-hold contrast-enhanced three-dimensional MR angiography of the abdomen: Time resolved imaging versus single-phase imaging. Radiology 2000;214:149-156 7. N Rofsky and M Adelman. MR angiography in the eva luation of atherosclerotic peripheral vascular disease. Radiology 2000;214:325-338 8. Earls], DeSena Sa nd Bluemke D. Gadolinium-enhanced three-dimensional MR angiography of the entire aOl1a and iliac arteries with dynamic manual table translation. Radiology 1998;209:844-849 9. Rydberg], Kopecky KK, Shalhav Al e( al. Evaluation of Prospective Living Renal Donors for Laparoscopic Nephrectomy with Multisection CT: The Marriage of Minimally Invasive Imaging with Minimally Invasive Surgery. RadioGraphics 2001 ;2 1:223S-236S 10. Berg M, Maninen H, Vanninen el al. Assessment of renal artery stenosis with cr angiography: usefulness of multiplanar reformation, quantitative stenosis measurements, and densitometric analysis of renal parenchymal enhancement as adjuncts to MIP film reading. ]CAT 1998;22:533-540
8:46 a.m. CTA of the Aorta and Lower Extremities GeoffelY Rubin, MD Stanford University School of Medicine Stanford, CA
9:09 a.m. MRA of the Aorta and Lower Extremities Martin R. Prince, MD, PhD Camel! Medical University New York, NY
:.,.-
1'-
!~.~~~
_...
nsufficien~y: -
--:to.:. ......::
~
.•,;:u.-;':""'l~.~.. ~j!;:r.
The, EndoluQ1inal', .,.,. ';.' ott
~ ~~.
,;.._.:
II
':I~ .,~r~tl~l!{~
iVloderator: Rodney D. Raabe, MD
Objectives: l. Distinguish trends in percutaneous vein ablatio n.
2. Examine strategies for clinical assessment of patients with vein insufficiency. 3. Describe available devices and ancillary techniques_ 10:30 a.m. Welcome Brian F. Stainken, MD Roger Williams Medical Center Providence, RI 10:35 a.m. Office Based Workup Neil M. Khilnani, MD Cornel! Vascular New York, NY History A directed problem specific patient history is obtained to understand the nature of the problems that e ncouraged the patient to seek a medical opinion or treatment. A standard medical history is supplemented with specific questions for patients with varicose and spider veins: 1. The presence of associated symptoms. Symptoms which are typically associated with varicose veins include pruritis, leg pain or heaviness, pal1icularly al the end of a day after prolonged standing, leg fatigue , restless or night cramps. One should quely abo ul the presence a history of any skin changes as well.
2. Previous treatments which the patient has undergone including surgery, endovenous and sclerotherapy. The response to each of these treatment and any complications should be speCifically addressed. The use of graduated support stockings, their effect on symptoms and how the patients tolerated this intervention should also be discussed with the patient. 3. Whether the patient has had any superfiCial or deep venous thrombosis is also an important pan of the history; this may help identify a patient with varicose veins secondary to deep vein occlusion or a patient with a hyper-coagulability syndrome. 4. Hormone medications or periods of hormonal flux , including the perimenopausal period can predispose to pigmentation following Sclerotherapy and shou ld be asked about 5. Concomitant disease may predispose some patients to complication or failure. These include peripheral arterial disease which can preclude the use of graduated compression hose.
P39