MRIs are also more accurate than CT scans since they are far more sensitive. They show all issues related to a stroke and any other diseases or concerning factors within the brain. MRIs are excellent at detecting even tiny abnormalities, which are often too small to be clearly seen in a CT scan.
Historically, cost, time, and availability have favored CT in the acute stroke setting. MRI offers superior infarct visualization, but it is slower. In the emergency setting, there is pressure to quickly treat patients with cerebral ischemia, while triaging those whose symptoms are explained by alternative diagnoses.
If a stroke is suspected, a CT scan is usually able to show whether you have had an ischaemic stroke or a haemorrhagic stroke. It's generally quicker than an MRI scan and can mean you're able to receive appropriate treatment sooner.
Strokes may not be seen on a CT scan for several reasons. It can sometimes take several hours for the brain to appear abnormal after the onset of stroke. The affected region may also be a part of the brain that CT scans do not image well, such as the cerebellum or the brainstem.
5 How- ever, earlier studies have shown that MRI may not detect acute strokes in 10-20% of patients. 4-6 Few clinical details of the false-negative cases were provided. Although several aspects of MRI techniques, computer software, and scan interpretations have been improved, false-negative MRI results may still occur.
When a doctor misreads a CT scan, however, this can lead to the misdiagnosis of stroke symptoms, putting the patient's life in danger.
With the increasing availability of CT scanners in Nigeria and increased scanner sensitivity for ischemic stroke, it is recommended that a suspected stroke patient should have a CT within 3 hours of symptom onset to allow for appropriate intervention to arrest progression of neurological deficits.
Where MRI really excels is showing certain diseases that a CT scan cannot detect. Some cancers, such as prostate cancer, uterine cancer, and certain liver cancers, are pretty much invisible or very hard to detect on a CT scan. Metastases to the bone and brain also show up better on an MRI.
Unlike a CT scan, which takes several hours to reveal any blockages of blood flow, an MRI can uncover any brain damage within an hour of the onset of the stroke symptoms.
Normal MRIs and CT scans can fail to find evidence of a large majority of brain damage. While you may feel confused or helpless at first, the important thing is to not give up.
You might need an MRI after CT Scan after the doctor has suspected any abnormalities and needs further scanning. It can be used to look at most areas of the body. Some parts of the body can be seen better in MRI than in CT scans. MRI has an upper hand in producing clearer and better pictures.
Large haemorrhages remain visible as such for 2–3 weeks. There is no “optimal” time to image stroke patients with CT and expect to show a definite infarct. Many infarcts do not become visibly hypodense until hours or even a day after the stroke, if ever.
A CT scan may even show evidence of early infarction -- an area of tissue that is dead or dying due to a loss of blood supply. Infractions generally show up on a CT scan about six to eight hours after the start of stroke symptoms.
Tests will be done to rule out a stroke or other disorders that may cause the symptoms: You will likely have a head CT scan or brain MRI. A stroke may show changes on these tests, but TIAs will not.
One of the most common stroke mimics is a seizure, which researchers believe account for as many as 20% of all stroke mimics. Other common stroke mimics include migraines, syncope, sepsis, brain tumor and metabolic derangement (low sodium or low blood sugar).
Purpose: MRI scans are great for creating very detailed 3D images of soft tissues, tendons, ligaments, your spinal cord and your brain. CT scans are better suited for imaging injuries from trauma, staging cancer, and diagnosing conditions in blood vessels.
Recovery time after a stroke is different for everyone—it can take weeks, months, or even years. Some people recover fully, but others have long-term or lifelong disabilities.
Even after surviving a stroke, you're not out of the woods, since having one makes it a lot more likely that you'll have another. In fact, of the 795,000 Americans who will have a first stroke this year, 23 percent will suffer a second stroke.
Expect your MRI to take at least 30 minutes while a typical CT scan may take only 5 minutes. And while CT is great for looking at a tiny bone fracture or an organ, an MRI is better for looking at soft tissue like your brain.
In some situations, your doctor may suggest MRI if a CT scan hasn't been able to give all the information they need. In some cancers, such as cervix or bladder cancer, MRI is better than CT at showing how deeply the tumour has grown into body tissues.
MRI is used to diagnose stroke, traumatic brain injury, brain and spinal cord tumors, inflammation, infection, vascular irregularities, brain damage associated with epilepsy, abnormally developed brain regions, and some neurodegenerative disorders.
A CT of the brain may be performed to assess the brain for tumors and other lesions, injuries, intracranial bleeding, structural anomalies (e.g., hydrocephalus , infections, brain function or other conditions), particularly when another type of examination (e.g., X-rays or a physical exam) are inconclusive.