Not all head trauma patients require neuroimaging. Studies have found that less than 10% of patients that are considered to have minor head injuries have positive findings on CT and less than 1% require neurosurgical intervention. However, there are still a small number of low risk patients that would benefit from neuroimaging. In the acute setting, early diagnosis and aggressive management may prevent secondary injury from the complications of brain injury. Proper management can significantly improve mortality and morbidity, while reducing hospital stay and health care costs.
WHEN IS A SPECT CT INDICATED WITH TRAUMATIC BRAIN INJURY?
Defining minor versus major head injuries has been problematic. Certain circumstances suggest major injury and almost always merit imaging such as worsening level of consciousness, loss of consciousness for more than 5 min, focal neurological findings, seizure, failure of the mental status to improve over time, penetrating skull injuries, signs of a basal or depressed skull fracture, or confusion or aggression. Even patients with the complete absence of clinical findings and high risk circumstances have been found to have intracerebral hemorrhage on imaging. Nevertheless, most investigators have focused on several criteria:
- Glasgow Coma Scale – The Glasgow Coma Scale (GCS), which rates a patient’s level of consciousness from 3 (worst) to 15 (no impairment) based on a patient’s ability to open his or her eyes, talk, and move, is often used to assess injury severity. Some have suggested that any score below 15 warrants imaging, whereas other investigators have suggested that imaging should not be performed unless the score is below 13
- Vomiting and Headache – Based on the New Orleans Criteria, all TBI patients with headache or vomiting should be imaged. More than two episodes of vomiting is considered by Canadian CT head rules as a high-risk factor for requiring neurosurgical intervention. The presence of headache or vomiting were not predictive of intracranial hemorrhage in the pediatric population though.
- Amnesia – transient amnesia is common after mild head injury. Longer and more severe amnesic episodes imply a greater chance of hemorrhage/brain damage. A SPECT study found that amnesia lasting more than half an hour is associated with bilateral cerebral hypoperfusion.
- Ethanol of Drug Intoxication – The New Orleans criteria list intoxication as an indication for imaging. Series have found that up to 8% of ethanol intoxicated patients had intracerebral injury; the presence of alcohol or other drugs of abuse may potentiate the effect of TBI on neurons and vasculature.
- Age (>60 years of infants) – According to the New Orleans criteria, all head injury patients over 60 years of age should undergo imaging, and according to the Canadian CT head rules, anyone over 65 years of age is at high risk for needing neurosurgical intervention. Studies have also shown a high incidence of intracranial injuries among infants who had no signs or symptoms, suggesting that imaging should be pursued more aggressively in younger children.
- Mechanism of Injury – Traumatic neurovascular injuries should be suspected in patients with a high-velocity mechanism, or low Glasgow Coma Scale score, or high injury severity score, AND mandible fracture, or teeth fractures, or complex skull fractures, or basilar skull fractures (including carotid canal fractures), scalp degloving, any type of cervical spine injury, and/or TBI with thoracic injuries, and/or thoracic vascular imaging, as well as in patients with penetrating neck injury (class I recommendation).
WHAT IS A SPECT CT?
A Single Photon Emission Computed Tomography (SPECT) scan is a type of nuclear imaging test that shows how blood flows to tissues and organs.
A SPECT scan is primarily used to view how blood flows through arteries and veins in the brain. Tests have shown that it might be more sensitive to brain injury than either MRI or CT scanning because it can detect reduced blood flow to injured sites.
SPECT scanning is also useful for presurgical evaluation of medically uncontrolled seizures (Fig. 1). The test can be performed between seizures (interictal) or during a seizure (ictal) to determine blood flow to areas where the seizures originate.
WHAT IS THE DIFFERENCE BETWEEN CT SCAN, SPECT and SPECT CT?
CT Scan (Computed Tomography) – images are obtained while you lie on a bed that moves into a ring, or “donut” shaped X-ray machine; the X-ray machine rotates over a 360 degree arc around the patient, allowing for image reconstruction in three dimensions. The X-ray machine from the CT scanner rotates much faster than the gamma camera, so the CT part of the study takes less time than the SPECT study.
SPECT images are obtained following an injection of a radiopharmaceutical that is used for nuclear medicine scans. The injected medication sticks to specific areas in the body, depending on what radiopharmaceutical is used and the type of scan being performed.
The radiopharmaceutical is detected by a nuclear medicine gamma camera. The camera or cameras rotate over a 360 degree arc around the patient, allowing for reconstruction of an image in three dimensions.
SPECT CT is where two different types of scans are taken and the images or pictures from each are fused or merged together. The fused scan can provide more precise information about how different parts of the body function and more clearly identify problems
The SPECT CT is a nuclear medicine tomographic imaging technique using gamma rays. It is able to provide true 3D information.
HOW IT WORKS
A SPECT scan integrates two technologies to view your body: computed tomography (CT) and a radioactive material (tracer). The tracer is what allows doctors to see how blood
flows to tissues and organs.
The technique requires delivery of a gamma-emitting radioisotope (a radionuclide) into the patient, normally through injection into the bloodstream. Before the SPECT scan, you are injected with a chemical that is radiolabled, meaning it emits gamma rays that can be detected by the scanner. The computer collects the information emitted by the gamma rays and translates them into two-dimensional cross-sections that is seen by the gamma camera. These cross-sections can be added back together to form a 3D image of your brain.
WHO PERFORMS THE SPECT CT?
A specially trained nuclear medicine technologist will perform the test in the Nuclear Medicine department of the hospital, or at an outpatient imaging center.
WHAT IS THE RADIOISOTOPE USED DURING INJECTION?
The radioisotopes typically used in SPECT to label tracers are iodine-123, technetium-99m, xenon-133, thallium-201, and fluorine-18. These radioactive forms of natural elements will pass safely through your body and be detected by the scanner. Various drugs and other chemicals can be labeled with these isotopes.
The type of tracer used depends on what your doctor wants to measure. For example, if your doctor is looking at a tumor, he or she might use radiolabled glucose (FDG) and watch how it is metabolized by the tumor.
The test differs from a PET scan in that the tracer stays in your blood stream rather than being absorbed by surrounding tissues, thereby limiting the images to areas where blood flows. SPECT scans are cheaper and more readily available than higher resolution PET scans.
HISTORY OF SPECT CT THROUGH HISTORY
Single photon emission computed tomography (SPECT) has a long history of development since its initial demonstration by Kuhl and Edwards in 1963. Although clinical utility has been dominated by the rotating gamma camera, there have been many technological innovations with the recent popularity of organ-specific dedicated SPECT systems. The combination of SPECT and CT evolved from early transmission techniques used for attenuation correction with the initial commercial systems predating the release of PET/CT. The development and acceptance of SPECT/CT has been relatively slow with continuing debate as to what cost/performance ratio is justified. Increasingly, fully diagnostic CT is combined with SPECT so as to facilitate optimal clinical utility.
SPECT CT is older than most other imaging modalities, SPECT has been a familiar and useful clinical device. But it didn’t come into widespread use until the 1980s.
In a sense, SPECT could be characterized as a medical and scientific tool that has waited a long time to be fully appreciated.
WHERE CAN I GET A SPECT CT – FOR TRAUMATIC BRAIN INJURY?
Please make sure you let the company know how you learned about SPECT CT and their company. I am hoping the more they are contacted the more facilities will be able to be opened as their is such a great need for this on a Global level.
Their website is http://www.cerescan.com. They have locations in Illinois, Louisiana, Florida, Texas, Alabama, Colorado, and California.
A referral from a doctor IS needed to schedule a SPECT CT with CereScan. Their Chicago/Arlington Heights (Illinois) location is different. Since there is an on site physician, he can write the orders if he deems it necessary. Their other locations do not have an onsite physician. Most people call CereScan directly and they either have a doctor that they educate or they recommend one of their affiliate doctors for patients to see.
CereScan provides different testing at different locations. Make sure you clarify what testing you are getting when scheduling at a particular location.
CereScan does accept various types of insurance. See Payment Options/Insurance Accepted
If your insurance does not qualify, they offer no-interest payments of up to 12 months. The price of one scan, neuropsych testing, clinical assessment and the report is quite affordable.
They no longer work with Care Credit.
You can reach them at 1-800-722-4806. Their FAQ page is at CereScan FAQ
Their website is http://www.amenclinics.com. They have locations in Georgia, Illinois, New York, California, Washington State, Washington DC
A referral from a doctor is NOT needed to schedule a SPECT CT with Amen Clinics.
Amen Clinics do not accept any insurance. They accept private cash pay up front or Care Credit. Their rates vary greatly based on what services you are looking for and what add-ons you agree to from their upselling.
You can reach them at 1-888-288-9834. Their FAQ page is at Amen Clinic FAQ
If you know of any organization that provides SPECT CT for Traumatic Brain Injury, please let us know at HOPE TBI – email us