Doctor insights on:
Is The Picture Different Between Contrast And Non Contrast
What to look for: CT venogram is a study for the veins of the body. Looking for something in the veins. Site of injection may be different timing different. CT with contrast has contrast material also. Timing also different ...Read more
Difficult to get: into the physics of it here, but a "traditional" or single slice scanner requires a separate scan for each slice. A spiral ct or multislice scanner employs a single scan with multiple detectors to acquire the entire volume of of data in the region being scanned. The patient moves through the scanner as the tube scans/rotates around the patient hence the descriptor "spiral". ...Read more
Liver lesions can have different measrmnts in CT vs US, where CT is more acurate.Can measurements also be differece between CT and MRI?
Yes and no.: The lesion could still be the same size, but the reported measurements can differ because of slight differences in the manual placement of the measurement calipers, as well as potentially measuring the lesion in different planes. ...Read more
Technique: Routine CT with contrast is usu. done with images taken with about a 90 sec delay after contrast is given IV. Images are viewed as cross sections and often sagittal (side views). Some places include coronal (frontal) too. CT urography also includes a set of 12-15 minute delayed images which are then reformatted in 3D. See picture. Both techniques often also employ non-contrast imaging as well. ...Read more
MRI/CT: A CT scan uses x-ray radiation to generate an image. An MRI uses magnetic fields "tuned" to the frequency of protons in the body. Since each scan essentially measures a different property of tissues in the body, they are complementary tests. That is why if one doesn't provide a definitive answer, often the other will be ordered. ...Read more
How do non contrast CT scans detect strokes? I was wondering how non contrast CT scans help diagnose strokes, since the non contrast would means that the parts of the brain with and without blood would all look the same, right?
A screening test: The earliest sign of a stoke on a ct scan is edema or swelling of the part of the brain that had the stroke. It may take several hours for this to show up on a ct scan, but ct scans are widely available 24/7, while MRI may not be. Ct can will show if the stroke is hemorrhagic, which will mean that treating the stroke with tpa (alteplase) is contraindicated. ...Read moreSee 2 more doctor answers
What is the difference between an enteroclysis CT and a normal CT? I drank two bottles and had an IV. Is the contrast different?
The CT: enteroclysis is specifically tailored to evaluate the small bowel, so the technical parameters of the scan are different than a standard abdomen CT. The intravenous contrast is the same. The oral contrast for the enteroclysis is generally different from the standard oral contrast. ...Read more
CT : Ct and MRI are complementary exams in many cases, which means that we can examine the same body area and get different "looks" to help us figure out what we are seeing. Ct uses ionizing radiation, while MRI uses magnetic fields to create images. (a physicist once reminded me that a magnetic field is also radiation, but the kind that people talk so much about, in relation to cancer potential, is the ionizing type.) example: when a kidney or liver mass is seen at ct, a radiologist might suggest that an MRI could help to further clarify (1) whether it is real, or (2) what it is. We don't always need an MRI to clarify a ct finding, just sometimes. That "sometimes" is determined by the radiologist, depending on how the abnormality looks at ct. ...Read moreSee 1 more doctor answer
What is the difference in diagnostics between mri, cat scan and colonoscopy? Which one is best for identifying problems?
Depends: Mri and ct scans are noninvasive imaging techniques. They have their own inherent advantages and disadvantages, and to compare them would be too complicated here. Colonoscopy is invasive, where a camera is extended via the rectum into the colon to see what the inside of the colon looks like, usually for cancer screening. ...Read moreSee 1 more doctor answer
Physics: The physical phenomena on which these imaging techniques are built are very different, each is best suited for different purposes. Cat scans are sophisticated x ray, they rely on the degree of absorption of gamma rays (bones, ca, other metals will contrast most). Mri is better for softer tissue imaging because it depends more on the behavior of hydrogen atoms and h2o in the strong magnetic field. ...Read more
MRV: Mri of the brain evaluates the brain tissue for any abnormal signal, lesions, or masses. An mrv (mr venography) uses special sequences to look at the venous structures (dural venous sinuses) around the brain. The main indication for mrv is to look for a clot or stenosis. Typically this is also done with IV contrast for better image quality. ...Read more
Why would a MRI of the back be ordered without, and with contrast? What is the contrast enhancing?
It depends: It depends what they are looking for. It is common to perform a spine MRI without/with contrast. If you had prior back surgery, it will help differentiate post surgical scarring(which enhances) from other processes like disc extrusion. Inflammatory and malignant abnormalities will also generally enhance. Vascular abnormalities will enhance. ...Read more
They give U choice?: May learn more from this link: https://www.insideradiology.com.au/gadolinium-contrast-medium/ ...Read more
Is there a lot of radiation associated with a CT scan with contrast for the renal area? Can the contrast cause an allergic reaction?
No: CT of abdomen is a fairly routine test and not considered a radiation danger. Th incidence of allergic reaction to contrast is 1-3% with non-ionic agents and 4-12% with ionic contrast agents.Non-contrast agents are the type generally used today. The benefit from the diagnostic value of the test far exceeds the risk of these 2 issues. Hope this answers your question. ...Read moreSee 1 more doctor answer
Are there different types of CT scans to clearly identify cervical stenosis? Just like there is a 32 slice MRI (extremely effective) vs. Just an mri?
Is an abdominal ct scan with & without contrast considered multiple scans or just one. Meaning is it more radiation, and how many scans are performed?
One scan: That is one scan. No worries about excess radiation exposure unless a patient needs serial scans, such as to monitor the abdomen every few months for many years after cancer treatment. In real life, having a few CT scans makes no difference compared to the total radiation one receives merely by living on planet Earth. ...Read more
Everything: Intravenous contrast helps show blood vessels, solid organs like the liver, and improves visualization of disease like tumors and infection. ...Read more
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