Radiology at MSc Diagnostic Imaging with. Word counts should be not more than 3000.Would you please follow the guidelines to avoid resit again . Moreover, I am going to upload the feedback of the module leader to have more information about the points which should be follow to prepare a successful coursework. According to the poster ,
This discussion study explores a radiological diagnosis of epilepsy based on a fictitious case of Mr Joshua who comes from a family with a history of epilepsy. This paper will provide a critical analysis of the diagnostic value, benefits and limitations of imaging modalities for diagnosing epilepsy.
Mr Joshua is 26 years old. For the last two years he has experienced varying incidences of seizure, including confusion and staring spells. On a few occasions, he lost consciousness. He has been admitted in the past. Mostly Joshua has been visited by the family doctor who advised him to see an epilepsy specialist.
Epilepsy is a disorder that causes the brain to signal abnormally (Fisher, 2014). Human brains have neurons which function in impulse generation. Each impulse acts on muscles and glands to trigger human action, feelings and thoughts (Mayo Clinic, 2013). In epilepsy, the neuronal activities are affected or disturbed, resulting in strange sensations and emotions, loss of consciousness, muscles spasms and sometimes convulsions. Epilepsy has a prevalence rate of 49 per 100,000 population.
Epilepsy can be traced to numerous possible causes. Some are a result of genetic influence and can be determined by the part of the brain affected and the type of seizure experienced (De Cocker et al, 2012). Several genes are tied to epilepsy with some acting as a trigger to induce conditions that cause seizures.
According to Shorvon, S.D. (2011) epilepsy has other causes such as:
1 . Head trauma such as accidental injury.
2 . Tumours and stroke.
3 . Infectious diseases such as meningitis, acquired immunodeficiency syndrome (AIDS) and viral
4 . Prenatal injury where the foetus is affected by poor maternal nutrition or oxygen deficiency.
5. Developmental disorders associated with autism and neurofibromatosis.
The risk of epilepsy is higher in people who are aged more than 60 years or who have a history of head injury, stroke or vascular diseases, adult dementia, brain infections such as meningitis, seizures in childhood, and family with epilepsy (MedicineNet, 2014).
Diagnosis of epilepsy is complex because the behavioural changes can be caused by other disorders with similar symptoms. Several tests can be used to investigate the possible causes (Benbadis, 2009). Doctors can request blood tests for infection, genetic conditions and others.
The doctor can also perform a neurological examination aimed at testing behaviour, mental function and abilities(Jones-Gotman et al., 2010).
In this case we are concerned with radiological techniques used to diagnose epilepsy, such as computed tomography (CT) scanning and magnetic resonance imaging (MRI) (Hartman et al, 2015) .
Others include electroencephalogram (EEG), functional MRI, positron emission tomography (PET) scanning, and single-photon emission computerized tomography (SPECT).
SPECT is never a primary test and is normally carried out after other tests such as MRI and EEG have failed to locate the position of the lesion. According to (Reynolds, 2002) SPECT is carried out by injection of a radioactive element into the patient’s vein to help with 3D mapping of blood flow in the patient’s brain during a seizure.
CT scan :
CT scan is more common and much faster than MRI. Therefore, most emergency patients with suspected epilepsy are referred for a CT scan so that the doctor can take a close look at their brain (Schachar et al, 2011). CT scanning provides relatively good imaging and is simpler to use (Al-Rawi et al, 2012). However, CT scans are not as detailed as MRI images and that affects the ability of the doctor to detect epilepsy (Gaillard, et al, 2009). At times, CT scanning is chosen to avoid anaesthetic, for example, if the patient has a heart condition.
CT scanning uses x-rays to take brain images that can be interpreted by the doctor (Panayiotopoulos, 2005). CT scan should be avoided during pregnancy due to the detrimental effect that x-rays can have on the foetus ( Solomou,Papadakis and Damilakis,2014).
CT scanning is used to check for conditions such as bone damage, internal organ injuries, blood flow complications and diseases such as cancers and stroke. In other cases, it is used to find the location, size and shape of a tumour, and at times it used to monitor the tumor condition (Miles, 2003).
CT scans have the advantage of being quick, painless and generally safe unless the patient is experiencing an allergic reaction (Redberg, 2009). They are safe because they are designed to minimize the level of X-ray exposure, and can be repeated many times without exposing the patient to harmful amounts of radiation( Rastogi, Lee & Salamon, 2015). CT is therefore a good method for detecting brain abnormalities such as infarction, lesion and underlying calcification (McVerry et al.,2014).
Magnetic resonance imaging :
Magnetic resonance imaging (MRI), though not commonly used compared to CT scan, gives better and clearer images. MRI uses strong magnetic fields and has better technical capability of showing the detailed structure of the brain (Ahsan, 2013). The multimodal imaging capability of MRI allows an increased chance of detecting epilepsy by enhancing images of the anatomical and pathological changes in the brain. Therefore, the test may be done if CT scan fails to indicate the size and location of the brain defect (Winston et al., 2013).
MRI is preferred for patients who develop epilepsy before the age of two years or after adulthood, when the epilepsy might have been triggered by brain injury, or when the patient continues to experience seizures after taking epilepsy medicine (Rugg-Gunn, 2014; Ahsan, 2013). MRI is the better option in a diagnostic role due to the amount and quality of morphological information it gives, and its ability to show cerebral blood flow (Peng et al., 2015).
MRI defines key areas of the brain since MR spectroscopy give much needed metabolic information (Antoch & Bockisch, 2009). MRI is able to detect epilepsy-related abnormalities such as hippocampus sclerosis, cortical malformations, vascular malformation, tumours, and acquired cortical damage (Rugg-Gunn, 2014).
Patients with metallic implants cannot undergo MRI due to possible fatal interaction between the MR signal and the metallic implant (Hussein et al, 2014; Porres et al, 2009).
Skull scanning is one area where CT scans are preferable to MRI because MRI is not able to show the bones of the skull or calcification ( Raut,Naphade and Chawla,2012).
Once structural imaging is enhanced through MRI, the seizure focus can be located based on lateralisation techniques (Lai et al, 2010). To complement the available information, health experts can use methods such as radionuclide imaging or advanced MRI in case of nonconcordant structural MRI findings ( Abraham and Feng,2011).
Treatment options and prognosis :
Treatment of epilepsy can take different directions depending on the patient condition (Scott et al, 2001). The treatment processes available are medication, surgery and therapy. Some patients react well to anti-epileptic medication and can have a reduced frequency of seizures or become seizure-free (Karceski et al, 2001) . Patients may experience side effects such as weight gain, skin rashes, loss of bone density, and memory and speech problems. Potential severe side effects include severe rash, organ inflammation, depression, and suicidal thought ( Cross,2010).
In cases where the seizure source is small and located in an area that does not interfere with vital functions such as speech or vision, surgery can be performed ( De Tisi et al., 2011).
When the affected part cannot be removed, a surgery called multiple subpial transection may be carried out to hinder spreading to other brain parts. However, the surgery is risky and might permanently interfere with cognitive ( Downes et al., 2015).
Therapy is another method of controlling epilepsy. The patient can be exposed to a ketogenic diet which is low in carbohydrate and high in fat. This is mainly applicable in children ( Klein et al., 2010). Another therapeutic option is vagus nerve stimulation, where a battery-powered stimulator is inserted beneath the skin near the chest and sends electrical signals through the vagus nerve to the brain. This method reduces seizures by 20 to 40 percentage ( Lagae and Arzimanoglou,2015).
Case presentation and analysis :
Mr Joshua had experienced a series of partial seizures which were accompanied by a loss of consciousness. He met with the family doctor to seek further physical examination to determine his mental and neurological condition which, according to his doctor, was a problem along his family line. As the personal doctor reiterated, Joshua had not previously been diagnosed with epilepsy and experienced the first partial seizure and mild loss of consciousness after his 24th birthday. Based on the family history, the series of mild seizures, and the loss of consciousness in the last two years and the last few hours, his personal doctor suspected emerging epilepsy and recommended that Mr Joshua undergo further investigation. At the hospital, the attending general physician recommended that Mr Joshua immediately go for a CT scan to evaluate his brain condition.
CT scan was chosen because it was readily available and safe. Further, Mr Joshua was undergoing his first head scan, and according to the National Institute for Health and Care Excellence ( NICE) guidelines, CT scan is recommended as an initial evaluation technique for patients suspected of neurological problems (Cohen, Klein & Mukundan, 2010) . The CT scan image did not give a conclusive result but indicated a possible lesion on the left hemisphere. After a discussion between Mr Joshua, his personal doctor and the attending general physician, Mr Joshua was put through contrast-enhanced CT, which confirmed Mr Joshua had a brain lesion on the left hemisphere which might have caused epilepsy. The general physician recommended that Mr Joshua visit a neuroradiologist to carry out further examination to help confirm the type of epilepsy. In line with NICE guidelines, the neuroradiologist recommended that Mr Joshua undergo an MRI scan to accurately locate the position and condition of the brain lesion (Rastogi, Lee & Salamon, 2015).
According to NICE guidelines, Mr Joshua had to be taken through preliminary MRI screening to determine his readiness for the examination. The purpose of preliminary MRI screening is to ensure that the patient is clear of any internal biomedical implants such as cardiac pacemakers which might react fatally with the MRI signals and impede the safety of the patient (Kaprelyan, Minchev & Tzoukeva, 2012). Mr Joshua had never had any implant. The screening was positive, and he was to have further tests carried out, such as T1- and T2-weighted MRI before and after intravenous injection of 1 mmol/kg gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) contrast agent ( Taheri et al., 2011).
MRI is important in neuroimaging and can help show the localization and lateralization of the seizure foci( Jansen et al., 2009). MRI gives high resolution images to enhance clarity (Henry, 2015). Mr. Joshua’s MRI indicated reduced hippocampus volume, slight alteration in inner brain structure and loss of differentiation between the grey and white matter of the brain. The MRI showed an image of a sharply marginated but non-enhanced hypointense lesion on the left insular cistern.
Mr Joshua was diagnosed with refractory epilepsy that is common in patients with structural brain lesions( Kaprelyan, Minchev and Tzoukeva,2012). The neurologist recommended that Mr Joshua be put on anti-epileptic drugs (AEDs), his condition be closely monitored, and he begin therapy.
Mr Joshua was diagnosed with refractory epilepsy. Given the location and the spread of the lesion, the neuroradiologist and neurosurgeons ruled out surgery and recommended Mr Joshua be put on a series of AEDs and that his condition be closely monitored to ensure he was receiving the right medication. Mr Joshua was to revisit the neurologist after six months.
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Fig 1: Magnetic resonance image of 17 years old Boy suffering from temporal lobe epilepsy
Source (Lai, Mak, Yung, Ho & Hung, 2015)
Fig 2: MRI showing Tuberous sclerosis of a patient suffering from multiple cortical and sub cortical supratentorial lesions (tubers)
Source (Kaprelyan, Minchev & Tzoukeva, 2012)
Fig 3: MRI imaging of the brain
Source (Rugg-Gunn, 2014)