Neuroimaging in Psychiatry — MCQs
What is the investigation of choice for diagnosing subarachnoid hemorrhage (SAH)?
Which of the following investigations work on the same principle?
Based on the provided image, which of the following is the correct diagnosis?
Dementia is seen in all except -
A lady presented with a 4 cm tumor in the left parietal lobe for which she underwent surgery and radiotherapy. After 3 months she presented with headache and vomiting. Which of the following would characterize the lesion in the patient?
Which imaging modality is most sensitive for detecting early ischemic stroke?
Which of the following behavioral problems would suggest an organic brain lesion?
Which of the following is false about bipolar disorder?
A 45-year-old male's blood test shows an increase in Homovanillic acid (HVA). Which of the following conditions is this finding most likely associated with?
Increased suicidal tendency is associated with which neurochemical imbalance?
Neuroimaging in Psychiatry Indian Medical PG Practice Questions and MCQs
Question 1: What is the investigation of choice for diagnosing subarachnoid hemorrhage (SAH)?
- A. Radionuclide scan
- B. X-ray skull
- C. MRI
- D. CT scan (Correct Answer)
Explanation: ***CT scan*** - A **non-contrast CT scan of the head** is the immediate investigation of choice for diagnosing SAH due to its high sensitivity for detecting fresh blood. - It can quickly identify the presence of **blood in the subarachnoid space**, especially within the first 6-12 hours after symptom onset. *Radionuclide scan* - This imaging technique uses **radioactive tracers** to evaluate organ function or blood flow. - It is **not used for acute diagnosis** of SAH, as it does not directly visualize blood in the CNS. *X-ray skull* - An **X-ray of the skull** primarily visualizes bone structures and can detect fractures or other bony abnormalities. - It is **ineffective at detecting blood** in the subarachnoid space and is not used for SAH diagnosis. *MRI* - While MRI can detect SAH, especially in subacute or chronic phases, it is **less sensitive than CT for acute SAH** due to longer acquisition times and motion artifacts. - It is often considered if CT is negative and clinical suspicion remains high, but **not as the initial investigation of choice** in an acute setting.
Question 2: Which of the following investigations work on the same principle?
- A. MRI and PET Scan
- B. CT and MRI
- C. CT and X-ray (Correct Answer)
- D. USG and HIDA Scan
Explanation: ***CT and X-ray*** - Both **Computed Tomography (CT)** and **X-ray** imaging utilize **ionizing radiation** to generate images of the body's internal structures. - They work by passing X-ray beams through the patient, with different tissues absorbing the radiation to varying degrees, which is then detected to create an image. *MRI and PET Scan* - **Magnetic Resonance Imaging (MRI)** uses **strong magnetic fields and radio waves** to create detailed images of soft tissues, based on water content. - **Positron Emission Tomography (PET) scans** use **radioactive tracers** to visualize metabolic activity and blood flow, detecting gamma rays emitted from the patient. *CT and MRI* - **CT scans** use **ionizing radiation** (X-rays) to produce cross-sectional images. - **MRI scans** use **magnetic fields and radio waves** and do not involve ionizing radiation. *USG and HIDA Scan* - **Ultrasound (USG)** uses **high-frequency sound waves** to create real-time images of organs and structures. - **Hepatobiliary Iminodiacetic Acid (HIDA) scans** are a type of nuclear medicine study that uses a **radioactive tracer** to evaluate liver and gallbladder function.
Question 3: Based on the provided image, which of the following is the correct diagnosis?
- A. Uterus didelphys
- B. Bicornuate Uterus
- C. Unicornuate Uterus (Correct Answer)
- D. Septate uterus
Explanation: ***Unicornuate Uterus*** - The image distinctly shows **only one fallopian tube and one rudimentary uterine horn** on the right side, indicating a unicornuate uterus. - This malformation results from the **incomplete development of one Müllerian duct**, leading to a single, banana-shaped uterine cavity. *Uterus didelphys* - This condition involves **two completely separate uteri**, each with its own cervix and vagina. - The image does not show evidence of two distinct uterine bodies or cervices. *Bicornuate Uterus* - A bicornuate uterus is characterized by **two uterine horns that fuse caudally**, creating a heart-shaped appearance with a shared cervix. - The image clearly lacks the characteristic heart shape and shows only one functional horn. *Septate uterus* - A septate uterus has a **fibrous or muscular septum** dividing the uterine cavity, while the external uterine contour remains normal. - The image does not show a septum or a normal external uterine contour with an internal division; instead, it presents with a single underdeveloped horn.
Question 4: Dementia is seen in all except -
- A. Huntington's chorea
- B. Pick's disease
- C. Alzheimer's disease
- D. Schizophrenia (Correct Answer)
Explanation: ***Schizophrenia*** - Schizophrenia is primarily a **psychotic disorder** characterized by delusions, hallucinations, disorganized thinking, and negative symptoms. While cognitive deficits are common, they typically involve executive functions, attention, and memory, rather than the widespread and progressive decline in multiple cognitive domains seen in **dementia**. - Although individuals with schizophrenia may experience significant cognitive impairment, it rarely leads to the profound and globally incapacitating cognitive decline that defines dementia. *Huntington's chorea* - Huntington's chorea is a **neurodegenerative disorder** that invariably leads to dementia, typically presenting as a subcortical dementia with prominent **executive dysfunction** and behavioral changes. - The cognitive decline is a hallmark feature alongside the characteristic **chorea** (involuntary movements). *Pick's ds.* - Pick's disease, now known as **frontotemporal dementia (FTD)-behavioral variant**, is a form of dementia specifically affecting the frontal and temporal lobes. - It is characterized by early and prominent changes in **personality, behavior, and language**, preceding significant memory impairment. *Alzheimer's disease* - Alzheimer's disease is the most common cause of dementia, characterized by progressive and severe impairments in **memory, judgment, language, and other cognitive functions**. - The accumulation of **amyloid plaques** and **neurofibrillary tangles** is the pathological hallmark of the disease.
Question 5: A lady presented with a 4 cm tumor in the left parietal lobe for which she underwent surgery and radiotherapy. After 3 months she presented with headache and vomiting. Which of the following would characterize the lesion in the patient?
- A. Digital subtraction angiography with dual source CT scan
- B. Gd-enhanced MRI
- C. 99Tc-HMPAO SPECT brain
- D. 18FDG PET Scan (Correct Answer)
Explanation: ***18FDG PET Scan*** - This patient, presenting with new neurological symptoms after **surgery and radiotherapy** for a cerebral tumor, faces a diagnostic dilemma: differentiating between **tumor recurrence** and **radiation necrosis**. - **18FDG PET scans** effectively distinguish between these two conditions because viable tumor cells exhibit high metabolic activity and thus actively take up **fluorodeoxyglucose (FDG)**, while radiation necrosis is metabolically inactive and shows little to no FDG uptake. *Digital subtraction angiography with dual source CT scan* - **Digital subtraction angiography (DSA)** is primarily used to visualize **vascular structures** and is not the modality of choice for differentiating tumor recurrence from radiation necrosis. - A **dual-source CT scan** is useful for rapid imaging and dynamic studies but lacks the metabolic information needed for this specific differentiation. *Gd-enhanced MRI* - While **Gd-enhanced MRI** is excellent for detecting **structural changes** and **blood-brain barrier disruption**, it often cannot definitively differentiate between **tumor recurrence** and **radiation necrosis**. - Both conditions can present with similar **enhancement patterns** on MRI, making differentiation challenging without additional metabolic information. *99Tc-HMPAO SPECT brain* - **99mTc-HMPAO SPECT** measures **regional cerebral blood flow (rCBF)**, which can be altered in both tumors and areas of radiation injury. - However, it does not provide the specific metabolic information (glucose metabolism) needed to reliably distinguish between **viable tumor cells** and **radiation necrosis** as effectively as FDG PET.
Question 6: Which imaging modality is most sensitive for detecting early ischemic stroke?
- A. Ultrasound
- B. PET scan
- C. CT
- D. MRI with DWI (Correct Answer)
Explanation: ***MRI with DWI*** - **Diffusion-weighted imaging (DWI)** within an MRI scan is highly sensitive in detecting **cytotoxic edema** within minutes of **ischemic stroke** onset. This makes it crucial for early diagnosis and treatment decisions. - DWI can identify areas of restricted water diffusion, which is a hallmark of acute cellular injury due to **ischemia**, even before changes are visible on conventional T1 or T2-weighted MRI sequences. *CT* - While frequently used in acute stroke settings, **non-contrast CT** is primarily used to **rule out hemorrhagic stroke** and may only show subtle or no signs of acute ischemia in the first few hours. - Early ischemic changes on CT, often referred to as the **"ischemic penumbra"**, may appear hours after stroke onset, making it less sensitive for very early detection compared to DWI. *Ultrasound* - **Transcranial Doppler (TCD) ultrasound** can evaluate blood flow velocities in intracranial arteries and detect stenoses or occlusions but is not a primary imaging modality for directly visualizing brain parenchymal ischemia. - Cervical ultrasound (e.g., **carotid duplex**) assesses extracranial vessels but cannot directly detect **ischemic changes** within the brain tissue itself. *PET scan* - **PET (Positron Emission Tomography)** can assess brain metabolism and blood flow but is typically not the preferred or most sensitive modality for **early detection of acute ischemic stroke** due to its complexity, cost, and limited availability in emergency settings. - PET is more commonly used in research or for assessing chronic conditions and **metabolic abnormalities**, rather than acute stroke diagnosis.
Question 7: Which of the following behavioral problems would suggest an organic brain lesion?
- A. Auditory hallucinations
- B. Formal thought disorder
- C. Depression
- D. Visual hallucinations (Correct Answer)
Explanation: ***Visual hallucinations*** - While visual hallucinations can occur in primary psychiatric disorders, they are *more commonly* associated with **organic brain lesions** (e.g., tumors, delirium, dementia, substance withdrawal) compared to auditory hallucinations. - They often indicate **neurological dysfunction** and warrant further investigation for an underlying physical cause. *Auditory hallucinations* - **Auditory hallucinations** are a hallmark symptom of **psychotic disorders** such as **schizophrenia**, and are less specific for organic brain lesions unless they are complex and multimodal. - While possible in organic conditions (e.g., temporal lobe epilepsy), they are more strongly linked to functional psychiatric illness than visual hallucinations. *Formal thought disorder* - **Formal thought disorder** (e.g., loosening of associations, word salad, tangentiality) is a core symptom of **schizophrenia** and other primary psychotic disorders. - It is a disturbance in the *form* of thought rather than its content, and is primarily a **psychiatric phenomenon**. *Depression* - **Depression** is a common mood disorder with diverse etiologies, including psychosocial stressors and neurochemical imbalances, but it is not typically indicative of a focal **organic brain lesion**. - Although depression can coexist with neurological conditions, it is not a direct behavioral symptom of a localized brain injury.
Question 8: Which of the following is false about bipolar disorder?
- A. Unipolar mania is more common than bipolar disorder (Correct Answer)
- B. Genetic factors play important role
- C. Rapid cycling is more common in females
- D. Age of onset is earlier than unipolar depression
Explanation: ***Unipolar mania is more common than bipolar disorder*** - This statement is **false** because **unipolar mania is extremely rare**, while **bipolar disorder (which includes both manic and depressive episodes)** is significantly more common. - **Unipolar mania** refers to recurrent manic episodes without any depressive episodes, a presentation that is seldom observed clinically. *Genetic factors play important role* - This statement is **true**, as **bipolar disorder has a strong genetic component**, with **heritability estimated between 60-80%**. - **First-degree relatives** of individuals with bipolar disorder are at a significantly higher risk of developing the condition. *Rapid cycling is more common in females* - This statement is **true**; **rapid cycling (4 or more mood episodes per year)** occurs more frequently in females with bipolar disorder. - **Women with bipolar disorder** are also more likely to experience **mixed features** and **more depressive episodes** compared to males. *Age of onset is earlier than unipolar depression* - This statement is **true** because the **typical age of onset for bipolar disorder is in early adulthood (late teens to early 20s)**, whereas **unipolar depression often has a later average onset**, though both can occur at any age. - An earlier age of onset in bipolar disorder is linked to poorer prognosis and more severe illness course.
Question 9: A 45-year-old male's blood test shows an increase in Homovanillic acid (HVA). Which of the following conditions is this finding most likely associated with?
- A. Phenylketonuria (PKU)
- B. Schizophrenia (Correct Answer)
- C. Depression
- D. Parkinson's disease
Explanation: **Explanation:** The correct answer is **Schizophrenia**. This question tests your knowledge of neurotransmitter metabolites and their clinical significance in psychiatric disorders. **1. Why Schizophrenia is correct:** **Homovanillic acid (HVA)** is the primary metabolic byproduct of **Dopamine**. According to the **Dopamine Hypothesis of Schizophrenia**, the disorder is characterized by dopaminergic hyperactivity, particularly in the mesolimbic pathway. Increased turnover of dopamine leads to elevated levels of HVA in the blood, cerebrospinal fluid (CSF), and urine. Monitoring HVA levels is often used in research to gauge central dopamine activity. **2. Why the other options are incorrect:** * **Phenylketonuria (PKU):** This is a metabolic disorder caused by a deficiency of phenylalanine hydroxylase. It leads to an accumulation of Phenylalanine, not HVA. * **Depression:** Depression is primarily associated with decreased levels of **5-HIAA** (5-Hydroxyindoleacetic acid), which is the metabolite of Serotonin. While dopamine can be involved, HVA is not a diagnostic marker for depression. * **Parkinson’s Disease:** This condition involves the degeneration of dopaminergic neurons in the substantia nigra. Therefore, one would expect a **decrease** in HVA levels due to dopamine deficiency, rather than an increase. **High-Yield Clinical Pearls for NEET-PG:** * **Dopamine → HVA** (Homovanillic Acid) * **Serotonin → 5-HIAA** (Decreased in suicide attempts and impulsive aggression) * **Norepinephrine → VMA** (Vanillylmandelic Acid) and **MHPG** (3-methoxy-4-hydroxyphenylglycol). * **VMA** is a crucial marker for diagnosing **Pheochromocytoma** and **Neuroblastoma**. * In Schizophrenia, HVA levels often correlate with the severity of positive symptoms (hallucinations/delusions).
Question 10: Increased suicidal tendency is associated with which neurochemical imbalance?
- A. Increased Noradrenaline
- B. Decreased Serotonin (Correct Answer)
- C. Decreased Dopamine
- D. Increased GABA
Explanation: **Explanation:** The neurobiology of suicidal behavior is most strongly linked to the **Serotonergic system**. Research consistently shows that low levels of **Serotonin (5-HT)** and its primary metabolite, **5-HIAA (5-hydroxyindoleacetic acid)**, in the cerebrospinal fluid (CSF) are associated with increased impulsivity, aggression, and completed suicide. This finding holds true across various psychiatric diagnoses, including depression and schizophrenia. **Analysis of Options:** * **Decreased Serotonin (Correct):** Low 5-HT levels in the ventromedial prefrontal cortex are linked to a failure in "top-down" inhibition, leading to impulsive-aggressive behaviors and suicidal acts. * **Increased Noradrenaline (Incorrect):** While noradrenergic dysregulation is seen in stress responses and anxiety disorders, it is not the primary neurochemical marker for suicidal tendency. * **Decreased Dopamine (Incorrect):** Low dopamine is primarily associated with anhedonia and motor symptoms (as seen in Parkinson’s or depression), but it is not as specific a predictor for suicide as serotonin. * **Increased GABA (Incorrect):** GABA is the brain's primary inhibitory neurotransmitter. Increased GABA activity is generally associated with sedation and reduced anxiety, not increased suicidality. **NEET-PG High-Yield Pearls:** * **CSF Marker:** The most high-yield fact is that **low CSF 5-HIAA** is the strongest biochemical predictor of violent suicide attempts. * **Post-mortem findings:** Studies of suicide victims often show decreased serotonin receptor binding in the prefrontal cortex. * **Genetics:** The Tryptophan Hydroxylase (TPH) gene mutation, which affects serotonin synthesis, is often studied in relation to suicidal behavior. * **Clinical Correlation:** Antidepressants (SSRIs) may initially increase the risk of suicide in young adults by increasing energy before improving mood (the "activation syndrome").
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