Question 1

please explain difference between ct, mri,  and pet scans. thank you?

Accepted Answer

Scans: Ct uses xrays and can visualize bone and soft tissue. Mri uses magnetic fields and can see soft tissue with much better detail if there is little motion. Pet scans are used to see tissue that is more active than surrounding tissue, looking for cancer or metastasis. It measures metabolic activity.

Question 2

what is better, a mri or a pet scan?

Accepted Answer

Depends on the ?: It depends on what you're investigating. If you want to know the metabolic activity of an area of brain in a disease state or in response to certain medications, then pet is the study of choice. However, if you want to visualize small or large lesions, vascular abnormalities, destruction of myelin, trauma etc. Then MRI is a better choice. Pet is used primarily for physiologic studies & research.

Question 3

how do a pet scan and a mri scan differ?

Accepted Answer

See below: An MRI or magnetic resonance imaging is a study that provides anatomical description of a part of your body. A pet scan can provide further information aside from how it looks or appears. It utilizes radioactive material or tracers that see how cells in your body function. It can detect cancer cells not evident on MRI or ct, heart disease, infection and even neurological conditions like dementia.

Question 4

what is a pet scan vs mri? what is the difference between a pet scan and an mri? is either one more comfortable from a patient's perspective?

Accepted Answer

The : The main differences between a pet scan and an MRI in terms of the information gained from the study are that a pet scan gives functional information whereas an MRI gives anatomic information. In terms of patient comfort, both examinations will require laying very still, usually on the back with arms either overhead or at the sides, for up to 30 to 60 minutes. The pet scan also involves more preparation and time before the actual scanning. For example, fasting for 4 to 6 hours and avoiding exercise for 24 hours, as well as laying quietly for one hour after the injection but before the scanning. A pet scan always involves an intravenous injection of radiotracer. An MRI is sometimes done with an injection (of gadolinium-based contrast medium), but other times is done without any injection, depending on what information is needed from the examination. Typically MRI exams that are performed for tumors or infection will use IV gadolinium, unless there is a specific contraindication to the use of contrast.

Question 5

what's the best test to detect a pheocromocytoma? besides a mibg? is it better to go with a pet scan or mri? i seem to have a sporadic pheo......

Accepted Answer

Neither: Serum or urine catecholamines, especially metanephrines.  Pheo is exceptionally rare - truly a one in a million incidence.

Question 6

can mri detect tumors(benign/malignant)? the mri only shws a lesion but do not knw if its benign. is it necessary to do a pet scan to find out more?

Accepted Answer

Yes: The  MRI is an effective way of defining a tumor.  The histologic diagnosis is suspected  mostly by presence and possible involvement of adjacent tissue.  When there is a question of trying to define the presence of a primary in the face of metastastic disease, the PET/CAT most often defines the presence of a Ca.

Question 7

how can i preparing myself for a pet scan? i am going to have a pet scan done soon and i wanted to know what to expect.  what are they? what do they look like? what do they detect? does it hurt? does it involve a tube like an mri does?

Accepted Answer

PET : Pet imaging is based on the positron-emitting radionuclide fluorine-18 (f-18), which is used as a labelling tracer on a glucose molecule that is injected intravenously before the scan. This labeled glucose molecule concentrates in areas of high metabolic activity such as tumor cells. F-18 decay releases a positron, which annihilates with a nearby electron, to produce two photons that leave the body in opposite directions and are detected by a ring of detectors. The raw data are reconstructed by a computer into cross-sectional images of the body. Many new pet scanners are hybrid instruments that combine a pet scanner with a ct scanner for combined anatomic and physiologic imaging. A patient couch runs through both scanning assemblies, and computer software fuses the two sets of images.

Before the scan, patients fast for 4 to 6 hours, and exercise is avoided for 24 hours. The radiotracer will be injected intravenously, and there may be mild pain or discomfort when the technologist first places the iv. Following the injection, the patient typically rests quietly for about one hour, without moving or talking. Just before the scan, the bladder is emptied either by voiding or by catheterization. During the scan, the patient lies on the back with arms either overhead or at the sides, depending on what body part is being examined and what position is best tolerated. The ct scan takes only about 2 minutes, and the pet scan takes between 30-60 minutes, depending on the anatomy covered.

Question 8

how can i ask for an mri or pet scan to see if there are any anomalies in my brain?

Accepted Answer

Need To See MD: You can not ask for a test to be done as these can only be ordered by a Physician and only if there is clear cut indication.You need to consult your Doctor for the symptoms you are having.Your doctor will take a detailed history and do an exam.Based on that he will decide if you need any tests done including imaging like MRI etc.So if you have any symptoms consult your Doctor

Question 9

the mri shows a lesion noted at the optic nerve and the orth.asked me to get a pet scan to find out more? is it necesaary?

Accepted Answer

Not clear on this: Which kind of doctor exactly asked you to get a PET scan? It looks like ORTHOPEDIC.  What is an orthopod doing getting an MRI of the head? At any rate, the only reason I can see that getting a PET scan following an MRI for a lesion at the optic nerve would be if there were a suspicion that the lesion were malignant. So, if that's the case then, YES it would be advisable to do it. Otherwise, no.

Question 10

cardiac mri, ctpa, egc 's, echo's, chest x-rays, pet scan, blood tests, ecg stress test. all these tests, no diagnosis. could something been missed?

Accepted Answer

Why the tests?: All results need to be interpreted in the clinical context and the doctor who ordered the tests is in the best position to do that. Having said that , it is not clear why you had these tests done in the first place? Do you have any symptoms? It would be prudent to have a detailed discussion with your doctor.

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Doctor answers about:

Mri and pet scans

A member asked:

Please explain difference between ct, mri, and pet scans. thank you?

A member asked:

What is better, a mri or a pet scan?

A member asked:

How do a pet scan and a mri scan differ?

A member asked:

What is a pet scan vs mri? what is the difference between a pet scan and an mri? is either one more comfortable from a patient's perspective?

A member asked:

What's the best test to detect a pheocromocytoma? besides a mibg? is it better to go with a pet scan or mri? i seem to have a sporadic pheo......

A member asked:

Can mri detect tumors(benign/malignant)? the mri only shws a lesion but do not knw if its benign. is it necessary to do a pet scan to find out more?

A member asked:

How can i preparing myself for a pet scan? i am going to have a pet scan done soon and i wanted to know what to expect. what are they? what do they look like? what do they detect? does it hurt? does it involve a tube like an mri does?

A member asked:

How can i ask for an mri or pet scan to see if there are any anomalies in my brain?

A member asked:

The mri shows a lesion noted at the optic nerve and the orth.asked me to get a pet scan to find out more? is it necesaary?

A member asked:

Cardiac mri, ctpa, egc 's, echo's, chest x-rays, pet scan, blood tests, ecg stress test. all these tests, no diagnosis. could something been missed?

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