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Imaging Newsletter, July 2009
Front row: Daniel S. Berman, MD FACC; John Friedman, MD. Back Row: Victor Cheng, MD; Louise E J Thomson, MBChB; Sean Hayes, MD.
Contact Numbers and Information for the S. Mark Taper Foundation Imaging Center
(Select Option 1)
|Imaging MD Line:||310-423-6500|
|Interventional Neuroradiology:|| |
- Consultation with a Cardiac Imaging Physician
- Thorough Cholesterol test, including: HDL, LDL, VLDL and triglycerides
- Scan on a 64-slice CT Scanner
- Same-day electronic reports
Coronary CTA: We routinely use a dose reduction protocol that has greatly reduced the radiation dose, flowing a strategy we published in the Journal of Cardiovascular CT in 2008 (Gutstein, et al JCCT 2008;2:311-322). Most patients can have our optimal protocol which has a 4 mSv dose.
Cardiac MRI: We routinely perform rest/adenosine MRI scans which are particularly helpful in women with suspected microvascular disease (angina with normal coronary angiograms). This is the only modality able to directly visualize the pattern of myocardial fibrosis, which is particularly helpful in evaluation of cardiomyopathy.
Nuclear Cardiology: We are installing a new fast SPECT camera that allows us to routinely perform a very rapid (one-half hour, similar to PET) low radiation dose thallium-201 studies (as low a dose as a standard technetium study).
Cardiac PET: We have the latest high resolution reconstruction software on our 64 slice PET/CT, and our work was featured in press releases at the Society of Nuclear Medicine meeting in Toronto in June, 2009. See the image shown in this letter.
We are one of two sites in LA currently performing research with a new cardiac PET myocardial perfusion tracer that has clearly superior characteristics as an imaging agent than all available tracers. We may be able to offer this unique imaging on a research basis to some of your patients.
Daniel S. Berman, MD, FACC
Chief, Cardiac Imaging and Nuclear Cardiology
The cardiac imaging team at the S. Mark Taper Foundation Imaging Center has more than 30 years of experience in patient care and cardiac imaging research. We currently have a staff of five fellowship-trained cardiologists who lead a team of physicists, technologists, nurses, and researchers. This exceptional combination of state-of-the-art equipment in all cardiac imaging fields, superb technologists, and specialized cardiac imaging clinicians--results in world-class patient care, and an unparalleled reputation for excellence. The center is known for pioneering research in cardiac imaging. We have developed imaging applications and software techniques for image interpretation that are being used worldwide.
Technetium-99m Shortage: As you may be aware, there is a worldwide shortage of technetium-99m, the radioisotope used for most nuclear cardiology procedures (sestamibi, tetrofosmin). This will not affect the availability of cardiac scans at Cedars-Sinai, since we have two excellent procedures that are equally good or superior to the standard rest/stress technetium scan.
Thallium-201 is an excellent tracer and can be substituted for technetium for exercise or pharmacologic stress. With the latest gamma camera technology, smaller doses can be used without compromising quality, leading to a decrease in exposure for the patient. For pharmacologic stress, we also offer Rubidium-82 PET studies. Cardiac PET is very fast for the patient (about 1/2 hour total imaging time) and permits assessment of peak stress ventricular function. Artifacts are minimal due to routine use of CT attenuation correction, which also often provides important structural information.
Radiation Doses: Due to heightened awareness of radiation exposure through medical imaging procedures, Cedars-Sinai has implemented radiation reduction approaches for all cardiac imaging studies. Our dual source CT is twice as fast as a standard single tube X-ray scanner, and is also equipped to modulate the X-Ray dose. The result is a substantial reduction in exposure, because we only scan at full energy during the small segment of the cardiac cycle needed for imaging the coronary arteries. The following table summarizes the amount of radiation with the methods as we are currently employing them. Everything is currently being expressed as milliSieverts (mSv) the standard, which is 1/10th of a rad.
Fast Turn-Around Time: Real time interpretation of studies throughout the day allows us to provide expedited service in this area. Our Nuclear Cardiology and Cardiac CT reports are sent (via fax, email and WebVS) the day they are performed and Cardiac MRI reports are provided within one day.
* mean from all of our protocols; including patients with irregular heart rhythm or other technical issue where dose reduction is not as marked.
- Background for a year: 3 mSv
- Coronary Calcium Scan: 2 mSv
- Coronary CT Angiogram: 3-8 mSv*
- Technetium-99m Rest/Stress: 10 mSv
- Thallium-201 "Fast Camera": 11 mSv
- Rubidium-82: 10 mSvDose is dependent on heart rate and weight of patient.
Cardiac MRI In Patient With IHSS
Cardiovascular magnetic resonance offers comprehensive non invasive assessment of cardiac structure, function and tissue characterization for patients with a variety of cardiomyopathies.
'Hypertrophic heart disease' includes a spectrum of diseases with increased thickness of the myocardium. Whereas normal wall thickness is approximately 8mm, hypertrophied muscle can measure over 3cm. This muscle becomes stiff and may obstruct normal blood flow within the heart. Symptoms include presence of chest pain and breathlessness and this process may be associated with increased risk of sudden cardiac death related to arrhythmia, or onset of heart failure. Hypertrophic heart disease may be inherited, and screening imaging is performed for the offspring of patients with this form of disease.
The images A-D (click on the images to see larger size) demonstrate the thickened appearance of the myocardium in a patient with an apical variant of hypertrophic cardiomyopathy (Yamaguchi's Syndrome).
The long axis image (A) shows four cardiac chambers with marked wall thickness increase in the distal left ventricle (*).
The corresponding contrast enhanced image demonstrates presence of scar within the abnormal myocardium (1).
Images C and D are corresponding short axis slices through the distal ventricle demonstrating the circumferential nature of the process with near obliteration of the ventricular cavity by hypertrophied muscle.
The images E - F demonstrate a case of asymmetric hypertrophy of the myocardium immediately below the ventricular outflow tract, with the turbulent flow below the aortic valve in a velocity coded MR image (E, arrow) and the corresponding anatomic image (F). Tagged imaging (H) is used to confirm the abnormal pattern of contraction within the diseased segment.
Cardiovascular magnetic resonance enhances the assessment of left ventricular hypertrophy, and represents a powerful supplemental imaging test to echocardiography with distinct diagnostic advantages for selected patients (2).
The non-invasive demonstration of dynamic obstruction, scar and extreme wall thickness aids in risk assessment (3).
- J Am Coll Cardiol. 2004 Jun 16;43(12):2260-4
- Circulation 2005;112(6):855-861
- J Am Coll Cardiol. 2003 May 7;41(9):1561-7.