Diagnostic Imaging

---

An ultrasound of the abdominal aorta is a non-invasive, painless test that uses high-frequency sound waves to image the "aorta," the main artery (blood vessel) which carries blood away from the heart to the rest of the body. Abdominal ultrasound testing can be used to evaluate the integrity of the artery walls, diameter of the artery at different locations and the presence and characteristics of atherosclerotic plaque. The ultrasound can be used to evaluate structural integrity of the aorta, as well as, evaluate the dynamics of blood flow through the artery. 

Weakness of the abdominal artery wall can lead to abnormal dilation (dictation) or in more severe cases to ballooning (aneurysm) of the artery .If the diameter of the order exceeds 3 centimeters it is referred to as an abdominal aortic aneurysm (AAA). Thoracic or abdominal aortic aneurysm can exist without symptoms until an emergent event occurs. As an aneurysm increases in size, the risk for a spontaneous rupture of the artery increases. Ultrasound imaging of the aorta can be used to screen for AAA. Quantitative arterial wall, arterial lumen and hemodynamic measures can be performed for future comparison. 

Screening is recommended for men over the age of 60 who have ever smoked and for anyone with a family history of AAA. The non-invasive ultrasound approach can be used as a safe and effective tool for monitoring the integrity of early-stage artery disease. .

A bone scan refers to a detailed imaging survey of bone to help identify a region of abnormality. The bone scan is capable of covering a large area in contrast to a regional X-ray of CT study. A bone scan may be performed to rule out an active inflammatory process within or involving bone such as a tumor, infection or fracture. A bone scan is performed by introducing a radioactive chemical marker into the blood through an intravenous (IV) line. A few hours after the administration of a radioactive chemical the patient is placed through a special scanner capable of detecting the radioactive marker wherever there is increased concentration. The distribution pattern of the radioisotope helps reveal and characterize disease states.

The bone scan is particularly sensitive at detecting disorders associated with a region of altered or increased bone metabolism. The study can help ascertain whether a bone fracture is new (active) or old (chronic). More recent fractures are generally associated with a region of increased signal on the bone scan due to greater concentration of the radioactive marker at the site of high bone turnover at the site of healing and repair. A bone scan is relatively good at identifying the region or regions of involvement but is not very good at revealing exactly what is going on at the tissue level. A positive bone scan typically warrants additional imaging such as an MRI or CT to further characterize pathology. Refined characterization of pathology helps direct personalized care.

 Computerized Axial Tomography often referred to as a CAT or CT scan is an advanced form of X-ray imaging. The CT device looks like a large square or donut with a whole in the middle. To perform a CT study the patient is placed onto a table (gantry), which slides into the hole within the imaging unit. CT scans provides two-dimensional detailed cross sectional images of the body. CT scanning is fast, painless and simple involving relatively limited radiation exposure. The CT study usually takes from 15 to 30 minutes to perform.

The CT scan can be performed using very thin slices. It therefore, provides excellent bone detail. It is advantageous for evaluating complex injuries and abnormalities of the head and spine. The CT scan can view of tissues at angles that can help identify soft tissue pathology and mass lesions including tumors. It can be helpful in the assessment of degenerative bone and joint conditions. A contrast agent may be administered by I.V. prior to the study to enhance the sensitivity of the evaluation process.

Like an X-ray a CT scan also works by sending an X-ray beam through the body. The information is captured, processed and formatted in a computer with sophisticated software. The computer can reformat and depict the tissue images at different angles. In some cases the information may be reconstructed in three dimensions and rotated to help with therapeutic planning. CT scans like routine X-rays studies do not provide the level of soft tissue detail available through the use of MRI. Specialized types of CT imaging are listed below:

Intrathecal Contrast Enhanced CAT Scan (Computerized Tomography with Myelography)

• This procedure is somewhat similar to a myelogram. The CT imaging study is performed after the administration of a contrast agent (radio-opaque dye) into the subarachnoid space (space within the spinal canal). The contrast agent offers a detailed view of the integrity of the spinal canal and nerve root sleeves. The patient can be moved or positioned so that the flow of contrast is directed to particular areas of interest. This dynamic option provides unique views of areas surrounding the spinal cord and spinal nerve roots. The use of contrast helps assess whether there is any physical compression or deviation of structures within the spinal canal and neuroforamen.

3D-CT scan

• The reformatted 3D CT scan is a computerized X-ray study which provides detailed information about bones and soft tissues in a three dimensional format. A 3D-CT is a longer test than a routine CT scan because more X-ray images are acquired in smaller sections at a variety of angles. At the completion of the study the technician uses a computer workstation to adjust gray scales, add color and digitally remove tissue signals to render tissues in a three-dimensional format for diagnostic assessment or therapeutic planning.

The coronary arteries are the blood vessels which supply oxygen containing blood to the heart tissue and muscle. The development of atherosclerotic plaque within the coronary arteries is often associated with a build-up of fat, calcium and other substances. Atherosclerotic plaque development and progression within the coronary arteries compromise blood flow to the heart muscle leading to impaired function, injury or death of the involved area. The latter is often referred to as a “heart attack”. Many of the risk factors for heart attack are able to be detected, monitored and modified to reduce risk. This includes the risk factors for developing progressive atherosclerosis.

The development of atherosclerosis is often asymptomatic or silent. The presence of high levels of calcium within one or more coronary arteries increases the likelihood of the presence of atherosclerosis with the calcium score correlating to the degree of atherosclerosis in many cases. Symptoms of plaque buildup in the coronary arteries may include exertional chest pain, chest discomfort and/or shortness of breath. Patient may also experience preferred pain to the mid back, to the jaw or into the left shoulder and arm. A specialized form of x-ray referred to as computed tomography (CT) can be used to perform screening heart scan which includes scoring of the calcium level within the coronary arteries. The scores are stratified on a report based upon risk. Coronary calcium scoring test is often used as a non-invasive CT screen of the heart. It can be used to calculate your risk of developing Coronary Artery Disease (CAD.

Discography is a provocative test used to help identify whether a specific intervertebral disc is contributing to back pain and/or extremity symptoms. The intervertebral discs are soft cushion-like pads which lie between the hard bony vertebral bodies of the spine. Standard diagnostic imaging tests such as plain X-rays, CT, MRI and myelography are not always helpful at detecting the primary source of back pain. In fact, these scans are limited to primarily revealed structure (anatomy) and therefore may not confirm the definitive source of spine pain. 

Pain which principally arises from an intervertebral disc is referred to as discogenic pain. Discogenic pain may radiate away from the spine. It may refer pain to the neck, mid-back, low back, chest, abdomen or extremities. Discogenic pain is often associated with disc degeneration and occasionally disc herniation. Discography may be performed to address whether a patient is a candidate for an interventional procedure or surgical fusion at the site of the involved disc. A negative discogram may help prevent unnecessary surgery. Because of the invasive nature of discography it is typically performed only if an invasive procedure such surgery is being considered. 

During the discogram procedure, an IV is used to administer antibiotics and medication to help the patient relax. The attending physician numbs the skin and then carefully inserts a needle into the back and then into the center of the suspected or control disc guided by X-ray (fluoroscopy). After the needle is properly positioned, a small amount of contrast (radiographically opaque dye) is administered into the center of the disc. The application of contrast contributes to elevated pressure within the intervertebral disc. If the injected dye reproduces the patients primary complaints the discography findings are referred to as concordant (correlates with) the patients pain. If the pain is not like the patients primary complaints the reproduced pain is referred to as discordant or not related to the primary painful complaints. A discogram is not performed to treat pain.

Often after a discogram is performed a thin slice CT scan is ordered to evaluate the morphology structural integrity (morphology) of the intervertebral disc. The radio-opaque dye that was injected helps to define the anatomical borders within the center of the disc. There are many risks associated with a discogram, which include but are not limited to infection, nerve damage and chronic pain.

A dexa scan is typically used to evaluate bone density of the hip or spine to assess the risk for fractures. It is a valid method for measuring the degree of osteoporosis, which refers to thinning of the bones. A dexa scan takes approximately 10-15 minutes to perform and is associated with minimal radiation exposure. The study is perfomed by sending low energy x-rays through the area to be visualized. Scan results may lead to appropriate treatment to reduce the risk for progressive thinning of the bone.

Neurosonography is an imaging procedure that uses ultra-high frequency sound waves to enable the physician to analyze blood flow or the integrity of neurological tissues. Neurosonography may be used to evaluate and localize intrinsic spinal cord pathology during neurosurgical procedures.  

The pedoscopic evaluation is performed by placing the patient on a specialized imaging platform. The weight bearing patterns along the undersurface of the feet are displayed and recorded. The study is usually performed as part of a postural or gait evaluation. It may also be performed as part of the diagnostic workup of a patient who has lower extremity weakness secondary to neurological compromise. Static weight bearing images may be compared to dynamic weight bearing assessment.

Positron Emission Tomography (PET) is a technique used for measuring the concentrations of positron-emitting radioisotopes within tissues of living subjects. PET can be broken down into several stages: (1) the labeling of a selected compound with a positron- emitting radionuclide (2) the administration of a compound to the patient to be studied (3) imaging of the distribution of the positron activity as a function of time by emission tomography and (4) eliciting, through the application of a suitable model, from the information thus acquired an understanding of the biological handling of the compound. PET provides a method for evaluating biochemical and physiologic states of tissue and organs including the brain and spinal cord. PET combined with CT 9PET/CT) is often used to reveal hypermetabolic regions which may represent metastatic disease in Individuals with known cancer. 

Computerized dynamic posturography is a specialized procedure used to evaluate balance and risk for abnormal gait. During the test, the patient is asked to open or close their eyes for brief periods of time. The platform and/or the surrounding booth may (dynamic) or may not (static) move. The body normally will automatically respond to pertubations of balance in a manner which restores balance and equilibrium. The use of a harness or hand rails helps prevent the patient from falling. A computer is used to automatically record test responses. The procedure is painless and takes about 15 to 30 minutes to complete. 

During posturography an individual may experience minor feelings of dizziness or imbalance. The presentation of abnormal signs or symptoms during the procedure provides your doctor with valuable information about your condition. A healthcare provider can learn a lot about the cause of dizziness or imbalance using posturography. The test examines an individual’s ability to use their sense of balance, the eyes, inner ear mechanism, as well as, proprioceptive input from their joints and muscles to adapt and achieve postural equilibrium. Testing scores the ability to achieve equilibrium while challenged on an unstable base. Used in this context represents a stress test. The ability to perform effective movements to regain balance is referred to as postural adaptation or recovery. The results of dynamic posturography can help your doctor determine the best course of treatment. 

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. 

X-rays utilize ionizing radiation to provide imaging of soft tissue and bony regions of the body including the spine. X-ray studies are particularly helpful in providing anatomic or structural detail about the integrity of bone and the relationship between bony structures. X-ray can be sued to reveal some soft tissue abnormalities. X-ray can be used to help identify spinal segment instability, joint subluxation, degenerative arthritis, degenerative disc disease, fracture, dislocations and tumors. X-ray assessment is one of the best methods for imaging the level and degree of vertebral segment malposition or dysfunction. 

X-ray studies are performed by sending an X-ray beam through the body region to be imaged. The dense calcium level in the bone blocks some of the X-ray beam penetration therefore providing a characteristic radio-opaque (white) appearance of the bone on the X-ray film. Normal intervertebral discs and nerve roots do not contain calcium and therefore, do not normally show up on X-ray studies. For this reason traditional plain x-rays of the spine cannot be used to confirm or deny the presence of a disc herniation or soft tissue compression of a spinal nerve root. A specialized multiplane form of x-ray referred to as a computerized tomographic (CT) scan can be used to provide greater detail of soft tissues than plain x-ray. Another specialized application of x-ray referred to as fluoroscopy can be used to document and analyze skeletal movement. 

Weight bearing spinal X-rays may be used for biomechanical assessment and to evaluate scoliosis. Functional or positional X-ray studies may be performed to characterize joint mobility and to rule out joint instability. Spinal X-rays provide the attending physician with the opportunity to evaluate the relationship between joint pathology (disease) and joint biomechanics (movement).