Angiography is a test used to image blood vessels. With MRI it can be performed with or without the use of a c0ontrat agent. With CT a contrast agent is entered into an artery. During the procedure a series of X-rays are taken to create a map of the blood vessels. The conventional angiogram provides an accurate way to assess the integrity of arteries of the head, neck, chest, abdomen and extremities. CT and MRI angiography is used to evaluate the degree of narrowing or dilatation of blood vessels and to assess the quality of collateral blood flow to a region. The study may also reveal disruption of the arterial wall such as that seen with arterial dissection. The study is also used to detect aneurysms, as well as, arterial, venous and arterial-venous vascular malformations. A conventional contrast-based angiogram is an invasive procedure requiring the insertion of a catheter. There are risks associated with the use of contrast. A magnetic resonance angiogram (MRA) can be period with or without the use of a contrast agent. The use of contrast can sometime offer greater blood vessel detail than non-contrast studies.
Body composition analysis refers to quantitative assessment of the distribution of muscle, fat, and water in the body. Body composition can be measured using a variety of different methods. One of the most accurate and practical methods is bioimpedance analysis (BIA). Body composition measurements play an important role in health, disease and sports. Excess body fat and abnormal distribution of body fat increases the risk for many diseases. Common disorders include metabolic syndrome and diabetes. In sports, excess fat or an abnormal ratio of fat to muscle impairs physical performance and places more stress on the spine and extremity joints. CNI uses state of art bio impedance technology to assess lean body mass, fat mass, water distribution, the body mass index (BMI), percent body fat (PBF), as well as, muscle and fat distribution.
Doppler ultrasound uses reflected sound waves (sonar) to help evaluate the velocity and quality of blood flow through an artery or vein. The sonar is also used to evaluate structural relationships (anatomy) and structural integrity. During the procedure the patient reclines on a table. The technician or physician applies a hand held transducer over the blood vessels to be evaluated. The transducer emits sound waves, which are reflected from the vessel and moving blood flow.
Specialized applications of doppler ultrasound include:
Carotid duplex scanning is a cost effective and accurate screening test and provides the
attending physician(s) with valuable information about the degree of artery narrowing
(stenosis) and the type of plaque which may be present in the artery. Vertebral artery circulation
may also be assessed before or after exercise in order to assess whether there is a subclavian
steal syndrome. An ultrasound study may be ordered if your physician hears an abnormal
sound over an artery (bruit) or if he or she suspects arterial insufficiency to the brain.
With progressive arterial narrowing there is a corresponding fall of the systolic blood pressure
below the site or sites of artery obstruction or narrowing. The extent to which the systolic
pressure falls is dependent upon the extent of blood vessel occlusion (narrowing) and the
integrity of collateral (additional) blood flow though other less compromised vessels.
To perform the study a pneumatic blood pressure cuff is applied to the limb to be tested and a
sensing unit (often a probe) is placed over a designated artery below the level of the cuff. The
cuff is rapidly inflated above systolic pressures, subsequently obliterating the flow to the region
be evaluated. As the pressure in the cuff is gradually deflated, the point at which flow is
resumed is recorded as the opening or systolic pressure.
The ABI findings are usually correlated with corresponding waveform analysis. A significant
drop in arterial systolic pressure in one limb suggests reduced blood flow secondary to
obstruction of one or more blood vessels. The presence of more subtle arterial obstructive
disease can be detected by increasing blood flow and blood pressure, either by exercise testing
or by inducing reactive hyperemia with an occlusive cuff. Patients with calcified vessels
(arteriocalcinosis) such as that seen in diabetics may present with falsely elevated ankle
pressures. In this case, pressure measurements can be made at the fingers or toes using
photoplethysmography (PPG) for more accurate results.
Cardiac ultrasonography (echocardiography) is a valuable non-invasive tool for imaging the heart and surrounding structures. It can be helpful for establishing a specific diagnosis and estimating the severity of various cardiac diseases. It is important to recognize, however, that the cardiac (heart) ultrasound exam is only a part of a more comprehensive heart work-up. Findings on the echocardiogram must be integrated with information obtained from the history and physical exam, cardiac and pulmonary auscultation, electrocardiogram (ECG), thoracic radiographs (X-rays) and other pertinent ancillary tests in order to accurately render a diagnosis and personalized care plan.
In general, echocardiography is used to evaluate heart chamber size, heart wall thickness, heart wall motion, heart valve configuration and motion, and the integrity of proximal great vessels. Doppler blood flow evaluation in the heart during an echocardiogram will help determine if congestive heart failure is present or whether heart valve insufficiency exists. The study is also used to assess thrombus development during the course of evaluating individuals with signs and symptoms of cerebrovascular disease and those who have had a stroke. Many echocardiographic findings are quantified making it is easy to compare values between studies.
Specialized forms of echocardiography include:
Electrocardiography (ECG), often-abbreviated EKG, is a non-invasive test used for detecting and monitoring heart disease. The multi-channel 12-15 lead ECG is particularly helpful at locating regions of tissue compromise and subsequent electrical abnormalities within the heart. Electrical signals generated inside of the heart triggers the upper muscular chambers (atria) to contract thus moving blood into the lower chambers (ventricles). Electrical signals progress in a specific way to trigger the lower chambers (ventricles) of the heart to contract; thus, propelling blood through the lungs and the body. There are specialized groups of cells within the heart that create the electrical signals. The signals travel over special pathways of cells referred to as the bundle branches. The pattern of electrical signal transmission is influenced by the health of heart tissue, the amount of blood and oxygen delivered to the tissue and by the autonomic nervous system regulation.
The electrocardiogram (ECG) is a test, which acquires an electrical recording of the heart from numerous angles. It is primarily used for the investigation of heart disease, although, it can be used to assess autonomic nervous system influence and regulation of the heart rate, rhythm and function. The resting ECG is performed by having the patient lie on a table on their back. A total of 12 to 15 superficial (stick on) recording electrodes are placed across the chest and on each of the extremities. The recording electrodes are hooked up to an interpretive computer, which provides a detailed printout of the results.
There are many different types of ECG tests which include the 12 lead resting ECG, the ambulatory ECG (Holter), the event recorder and the graded exercise test (GXT) or stress test. The ambulatory ECG refers to recording of the hearts electrical activity for a prolonged period of time such as 24 hours or more. During an ambulatory ECG the patient wears the recording unit on their waist with electrodes hooked to their chest as they go through their normal day. The patient may be asked to keep a time stamped diary while wearing the unit.
Because the routine resting ECG is conducted over a very short period of time (10-15 seconds), the study may not reveal intermittent heart rate, heart rhythm or other forms of electrical irregularities which do not occur during the test period. There are specialized types of ECG protocols which can be applied during the course of a resting study to expand the examination process. The more common electrocardiographic studies are listed below.
Specialized form of ECG studies include:
Pulse oximetry is a simple non-invasive method of monitoring the percentage of hemoglobin (Hb) in the red blood cell, which is saturated with oxygen. The pulse oximeter consists of a probe or special clip, which can be placed onto a patients’ fingertip, toe or ear lobe. Most pulse oximeters have an LED readout, which may be linked to a computer. The unit displays the percentage of hemoglobin saturated with oxygen. The normal value is 66-100%. Audible alarms can be set during a procedure or for general monitoring purposes. Oxygen saturation measurements can be compared between the digits of the upper extremities and the lower extremities by placing the unit on a finger and then on a toe. This approach may help reveal regional variations in blood flow.
Phonoangiography refers to the use of acquiring and analyzing sound to evaluate the integrity of blood flow through an artery. The procedure is performed by placing a sensitive microphone over an artery of interest. Common uses include evaluation of the carotid arteries, aorta, femoral arteries and popliteal arteries behind the knees. The specialized microphone is used to acquire and record blood flow sounds. It can certainly be used to help detect regions of blood vessel narrowing and occlusions, such as those caused by atherosclerosis. Specialized application referred to as digital phonoangiography, offers the user the ability to apply special filters and to adjust the volume and rate of recorded sound without distorting its features. The acquisition of digital information supports quantitative analysis of sounds produced by blood flow.
Phonoangiography, has been used to investigate local fluid motion in arteries narrowed by atherosclerosis. Phonoangiography often is used as an extension of the physical examination. On occasion that they be utilized in a special lab for very detailed assessment which is used to complement other diagnostic findings. Quantitative analysis can be used to infer arterial attributes such as vessel diameter, blood flow velocity, local turbulence intensity, and blood vessel wall pressure fluctuations.
Plethysmography is used to evaluate blood flow. The testing can be performed using a variety of recording devices such as a strain gauge, photocell, air techniques and doppler. All of the methods are well established and are used for the evaluation of peripheral vascular disease; although, with recent advances in ultrasound the need for plethysmography has decreased dramatically. Plethysmography is not as accurate as duplex scanning and is more operator dependent. However, PPG is still routinely used for the evaluation of small blood vessels (microvasculture), suspected thoracic outlet syndrome, digital ischemia and Raynaud's presentations. Recording over a digit allows the limb to be placed in provocative positions to assess whether there is positional impingement of blood flow to the extremity.
A special microscope and camera is used to view and image the back of the eye, an area referred to as the retina. The images reflect the health of numerous tissues including the optic nerve, macula, retina and small blood vessels at the back of the eye. The images and image data is used to diagnose systemic and eye conditions. The information is also used for objective documentation and comparative studies. The integrity of small blood vessels in the back of the eye often represents changes in the brain and other tissues. The retina is the window to small blood vessel health. It is subsequently an important test for individuals with diabetes, clotting disorders, autoimmune disease, arterial hypertension and stroke risk.
There are two types of retinal imaging systems. One requires that the pupil of the eye be dilated with medication to allow for adequate imaging of the eye. The other type of microscope is referred to as a non-mydriatic camera and it is designed to image the inside of the eye without using medication to dilate the pupil. Both imaging system can be linked to a computer which can be network with a data storage and analytic system off site (in the cloud). Retinal imaging data can be sent to a remote expert for interpretation. This process is often refed to as telehealth, or more specifically tele-ophthalmology. In some cases artificial intelligence solutions may be used to assess the image.
A great deal can be learned about the mechanical and functional properties of the pulmonary airways and the lungs from measurements of forced breathing such as maximal expiration and inspiration. Spirometry is the term often applied to the quantitative assessment of breathing. Over the years it has become obvious that the spirometer and peak flow meter used to measure ventilatory function are as deserving of a place in the diagnostic workup as the sphygmomanometer for those individuals with chest or respiratory symptoms. Accurate spirometry measurements are dependent on correct operation and accuracy of the spirometer, performance of the correct breathing maneuvers and use of relevant predicted normal values.
Spirometry can be used to assess neurological function, particularly the integrity of the upper part of the spinal cord. The phrenic nerve carries nerve impulses from the spinal cord to the large muscles of breathing referred to as the diaphragm which lie within the upper abdomen at the base of the lungs. Spirometry can be used to assess the flexibility of the spine and the expansibility of the bony aspects of the rib cage. The rib cage must contract and expand with each breath. Certain disease processes and pain syndromes can restrict excursion of the chest. Spirometry is most often used to assess the health of the lungs.
T-wave Alternates (TWA) represents a specialized form of EKG used to detect the risk for developing irregular heart rhythms. The test requires placement of superficial specialized electrodes on the chest. The individual’s heart rate is typically raised to a submaximal level during which time electrical measurements are acquired and analyzed. T-wave alternans measures beat-to-beat fluctuations in the timing or shape of the ECG T-wave. The T-wave represents one element of the electrical wave complex associated with each individual heartbeat. TWA testing may be performed as part of a more comprehensive heart workup.
T-wave Alternans (TWA) represents a specialized form of EKG used to detect the risk for developing irregular heart rhythms. The test requires placement of superficial specialized electrodes on the chest. The individual’s heart rate is typically raised to a submaximal level during which time electrical measurements are acquired and analyzed. T-wave alternans measures beat-to-beat fluctuations in the timing or shape of the ECG T-wave. The T-wave represents one element of the electrical wave complex associated with each individual heartbeat. TWA testing may be performed as part of a more comprehensive heart workup.
The tilt table study is often used to evaluate patients who have had syncope (loss of consciousness) or near-syncope (near loss of consciousness). It is an extremely simple study, and in most cases quite safe. A tilt table study is performed with the patient strapped to a table, which is then mechanically tilted to a predetermined upright position.
The table is tilted while monitoring an individual’s pulse, blood pressure, electrocardiogram, and sometimes blood oxygen saturation. The patient may be left in a “motionless standing position” for 20 to 30 minutes. When the patient's syncope is reproduced during the test, a "positive" tilt table study is said to have occurred.
During an upright tilt and while standing a person's cardiovascular system has to adapt to main adequate vascular perfusion and to prevent a significant portion of blood volume from pooling in the legs. These adjustments consist of a mild increase in heart rate, and a constriction of the blood vessels in the legs. When a normal individual is placed in an upright tilt, these cardiovascular adaptations occur very quickly, and there is no significant drop in the blood pressure. In patients with neurological conditions such as orthostatic hypotension and vasovagal syncope, the autonomic nervous system regulation of the cardiovascular response does not work right.