Radiology is a study of medical technology, it is a important discipline included in the MBBS typically introduced in the later years of medical training. It covers various imaging techniques used to diagnose and manage diseases, including X-ray, ultrasound, computed tomography, positron emission tomography, nuclear medicine and magnetic resonance imaging.

Radiology serves as a critical link between clinical medicine and diagnostic image technology helping medical professionals to visualize internal structures and identify pathological conditions.

A strong grip in radiology for medical students is important, as it aids in accurate diagnosis, treatment/management planning and monitoring of diseases progression with stages.

The radiology curriculum in MBBS covers topics like principles of imaging modalities, anatomy in imaging, interpretation of radiographs, advanced imaging techniques, radiation safety, and the role of radiology in various clinical scenarios, including trauma, oncology, and pediatric care.

Important Topics in Radiology

In the NEET-PG examination 10- 15 questions are asked, while in the INI-CET there are about 15-20 questions that are based on the Radiology Subject.

These competitive exams mainly cover the extent of the candidates’ knowledge about medical imaging procedures, diagnosis diagnostic accuracy principles and role of radiology in clinical practice.

Acquaintance of subject weightage, typical examination formats, areas of significant potential for high yield and general study strategies can greatly help to improve conceptual understanding of Radiology exam.

Imaging of All Emergencies

• Pneumothorax
• Tension Pneumothorax
• Pneumomediastinum
• Pneumoperitoneum
• Pneumocephalus
• Aortic Dissection
• Aortic Aneurysms and Rupture
• Pseudoaneurysms-Yin yang sign
• Pulmonary Thromboembolism Stroke Imaging-Acute Infarct
• Hyperdense MCA sign
• DWI
• Head Trauma-Epidural hematoma
• Swirl sign
• Subdural hematoma
• Subarachnoid hemorrhage
• Intraparenchymal and intraventricular bleed Abdominal Trauma-FAST
• CECT liver lacerations
• Splenic injury Acute Abdomen-Acute Pancreatitis
• Small and large Intestinal obstruction and Volvulus

X-Rays

Concepts of Kilovolt Peak (KVP) and Milliampere-Seconds (MAS)

• KVP (Kilovolt Peak): Refers to the maximum voltage applied across the X-ray tube, influencing the quality and penetrability of the X-ray beam. Higher KVP results in better image quality with less radiation exposure.
• MAS (Milliampere-Seconds): Indicates the quantity of X-ray exposure, combining the current (mA) and the duration (s) of the exposure. It affects the density and contrast of the image.

Important X-ray Views

• Water View
• Caldwell View
• Rhese View
• Stryker’s View
• Schuller View
• Lordotic View
• Reverse Lordotic View

Radiation Interactions

• Compton Effect
• Photoelectric Effect
• Bremsstrahlung Radiation

Mammography Technique

• Differences from Conventional Radiography

Hysterosalpingography Images

• Normal
• Unicornuate Uterus
• Bicornuate Uterus
• Didelphys Uterus
• Hydrosalpinx

IVP Images

• Ureterocele
• Droopy Lily Sign
• Retrocaval Ureter

CT Scan

Types of CT Imaging

• Spiral CT
• HRCT (High-Resolution CT)
• MDCT (Multidetector CT)
• Dual Energy CT

CT Anatomy

• Brain
• Mediastinum
• Abdomen
• Lungs

Coronary Calcium Scoring

• Agatston Scoring

CT Angiography

• Pulmonary Thromboembolism

Radiation Protection

• Lead Apron
• TLD Badge (Thermoluminescent Dosimeter)

MRI Indications and Contraindications

• MRI Sequences: T1-weighted imaging, T2-weighted imaging, FLAIR (Fluid-Attenuated Inversion Recovery), STIR (Short Tau Inversion Recovery), DWI (Diffusion-Weighted Imaging), DTI (Diffusion Tensor Imaging).
• MR Spectroscopy
• MRI Planes: Axial Images, Coronal Images, Sagittal Images of brain

USG

• Piezoelectric Effect: General of electrical charge in certain materials under mechanical stress
• Ultrasound Phenomena: Posterior Acoustic Shadowing, Posterior Acoustic Enhancement
• FAST (Focused Assessment with Sonography for Trauma
• EFAST (Extended FAST)
• EUS (Endoscopic Ultrasound
• Doppler Ultrasound Techniques: Color Doppler, Spectral Doppler
• Doppler Assessments: Umbilical Artery Doppler, Uterine Artery Doppler, Fetal MCA (Middle Cerebral Artery) Doppler

Radiotherapy

1. Teletherapy

• Linac
• Stereotactic Radiotherapy
• IMRT (Intensity-Modulated Radiation Therapy)
• Craniospinal Irradiation
• Electron Beam
• Proton Beam: Bragg Peak

2. Brachytherapy

• Permanent and Temporary Implants
• Pura Beta Emitters

3. Systemic Radiotherapy

• I-131
• Strontium-89
• P-32

4. Law of Bergonie and Tribondeau

5. Radiosensitivity of Tissues and Tumors

6. Different Iodine Isotopes

• I-131
• I-125
• I-124
• I-123

7. Half-Lives of Important Radioisotopes

• F-18
• Tc-99m
• Iodine Isotopes
• P-32
• Co-60
• Cs-137

Nuclear Medicine

• Thyroid Imaging: Thyroid Scintigraphy, Lingual Thyroid
• Renal Scans: DMSA, DTPA, MAG-3 Scan
• Cardiac Imaging: Myocardial Perfusion Imaging, Myocardial Infarct Imaging
• Bone Imaging
• Sulfur Colloid Scan
• Tc-99m Sestamibi Scan
• Octreotide/Somatostatin Receptor Scintigraphy
• PET Imaging
• HMPAO-SPECT

Neuroradiology

• Imaging of Meningioma
• Tumor Comparisons: Medulloblastoma vs. Ependymoma, Arachnoid Cyst vs. Epidermoid Cyst, Craniopharyngioma vs. Pituitary Adenoma
• Important Named Signs: Mount Fuji Sign, Racing Car Sign, PAND Sign, Hummingbird Sign
• CNS Conditions: TB Meningitis, Creutzfeldt-Jakob Disease (CJD)
• Imaging of Stroke: Hyperdense MCA Sign, Penumbra, CT Perfusion Imaging
• Intracranial Bleeds: Extradural Bleed, Subdural Bleed, Subarachnoid Bleed, Intraventricular Bleed, Intraparenchymal Bleed

Respiratory Radiology

• X-ray Views: Posteroanterior vs. Anteroposterior View
• Medical Conditions: Collapse, Consolidation, Pleural Effusion, Pneumothorax
• Important Signs: Golden S Sign, Luftsichel Sign, Silhouette Sign
• Specific Conditions: X-ray of Pulmonary Edema, Sarcoidosis, Pulmonary Thromboembolism
• CT Imaging: Bronchiectasis, Interstitial Lung Disease, Pulmonary Alveolar Proteinosis
• Fungal and Parasitic Infections: Aspergillosis, Hydatid Disease of the Lung, Lung Abscesses, Fungus Ball, Hydropneumothorax
• Other Findings: Lucent Hemithorax, Foreign Body

Schizophrenia is a serious mental illness that impacts about 1% of the global population. It is characterized by symptoms such as hallucinations, delusions, disorganized speech, and severely disorganized behavior. Additionally, individuals may experience negative symptoms, including diminished emotional expression, lack of motivation (avolition), and cognitive impairments.

Excessive dopamine is found in schizophrenics. Drugs that increase or decrease dopamine are known to worsen or make schizophrenia better.

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Schizophrenia Pathophysiology

Schizophrenia’s pathophysiology involves multiple molecular and neural circuit changes, though it’s unclear whether these are direct causes or adaptations to underlying dysfunctions. No current model fully explains all observed changes.

Neurotransmitter imbalances, particularly involving dopamine, serotonin, glutamate, and GABA, are central to schizophrenia. The connection between dopamine and schizophrenia was highlighted by the discovery that D2 receptor blockers can alleviate psychotic symptoms. Four key dopamine pathways—mesolimbic, mesocortical, tuberoinfundibular, and nigrostriatal—play distinct roles. Excessive dopamine in the mesolimbic pathway is linked to positive symptoms, while reduced dopamine in the mesocortical pathway may lead to negative symptoms and cognitive deficits. The nigrostriatal pathway is associated with motor side effects of antipsychotics, and the tuberoinfundibular pathway relates to hyperprolactinemia.

Recent research in cognitive neuroscience has shown that mesostriatal dopamine neurons respond to “reward prediction error,” helping assign significance to stimuli. In schizophrenia, dysregulated firing of these neurons can lead to misattribution of importance to irrelevant stimuli, contributing to delusions and hallucinations.

The relationship between dopamine and schizophrenia is complex, as evidenced by the delay between D2 receptor blockade and clinical response to antipsychotics, suggesting secondary neurochemical mechanisms are also at play. Additionally, the interplay among dopamine, glutamate, and GABA is critical for regulating cortical circuits, with postmortem studies indicating alterations in these microcircuits. This has prompted exploration of targeting glutamate and GABA pathways for improved treatment options.

Stages of Schizophrenia

Phase 1: Initial diagnosis for the earliest signs of schizophrenia.

Phase 2: These are the periods between exacerbations of symptoms, which are relatively calm, but may be deteriorating.

Phase 3: Exacerbation or relapse with increased use of resources.

Major Types of Schizophrenic Disorders

1. Disorganized Schizophrenia: Personality is severely disorganized, which includes hallucinations, inappropriate behavior and regression.
2. Catatonic Schizophrenia: Acute stupor and sudden loss of animation that alternates with periods of excitement and over activity.
3. Paranoid Schizophrenia: Suspicious of everyone and ideas of persecution or grandeur.
4. Undifferentiated Schizophrenia: Prominence of psychotic symptoms from more than one subtype or that does not meet the criteria for any subtype.
5. Residual Schizophrenia: Absence of prominent psychotic symptoms but continued evidence of symptoms of symptoms such as peculiar behavior and blunted affect.

(Hebephrenic) Disorganized Schizophrenia Type

Individual has facial tics and grimaces, characteristic rises sardonic smile, flat affect with no emotion or strong feeling and in between blunt affect, Volitional affect, and labile affect. Almost all affects are oriented to time place and person.

Pathognomonic are very characteristic:

• Clanging- Rhyming ‘Go to hell, bell’ (pathognomonic).
• Echolalia- Repeating phrase- repeats back “When did you come?”
• Neologisms- Uttering new words without any meaning.
• Pathognomonic are schizophrenics until rules out.

Catatonic Schizophrenia Disorder

Presence of psychomotor retardation, thought process is slow, walking slowly and flexibility is slow. Tendency to talk as though the other person isn’t there! Its tendency is very harmful.

Sometimes rage is combined with anger catatonic excitement and grand blow up can come out with insensitivity to staff.

Increased stress is like increased catatonic excitement.

Paranoid Schizophrenia

The individuals are intelligent with inflated ego (think they are someone special).

Basically, they have severe auditory hallucinations and fear of persecution. They have such fears about safety such as CBI is after them, they being controlled by special messages through electronic media. All delusions start with a kernel of truth.

Undifferentiated Type

The individual has a lot of symptoms. They may have symptoms of all other types so that it is difficult to differentiate.

Kinesics Nonverbal Behaviors

Bizarre behaviors which are outlandish, ridiculous and abnormal but not for drawing attention like shaving of one side of moustache, rose on one side of cheeks, etc.

Symptoms of Schizophrenia

Here are some of the symptoms associated with schizophrenia:

Primary Symptoms of Schizophrenia

• Delusions: False beliefs maintained against logic and contrary evidence.
• Loosening of Associations: Ideas skip from one thought to another in unrelated way.
• Hallucinations: False sensory perceptions in the absence of actual external stimuli.
• Positive Symptoms reflect the presence of unusual behavior and related distortions in form and content of thought.

Secondary Symptoms of Schizophrenia

• Disturbances in affect often blunt or flat.
• Disturbances in volition inability to initiate goal-directed activity.
• Disturbances/interpersonal functioning often withdrawn from others (in the extreme autism).
• Increases psychomotor activity or decreased psychomotor activity.
• Negative symptoms reflect the absence of normally expected behavior.

Diagnosis of Schizophrenia

The diagnosis of schizophrenia relies on two primary systems: the DSM-5-TR and the ICD-10, each with slight variations.

1. DSM-5-TR

The DSM-5-TR, published by the American Psychiatric Association (APA) in 2022, outlines the following criteria for diagnosing schizophrenia:

• Symptom Presence: The patient must exhibit two (or more) of the following symptoms for a significant portion of time during a 1-month period (or less if successfully treated). At least one symptom must be one of the first three:
  • Delusions
  • Hallucinations
  • Disorganized speech (e.g., frequent derailment or incoherence)
  • Grossly disorganized or catatonic behavior
  • Negative symptoms (e.g., diminished emotional expression or avolition)
• Functional Decline: There must be a noticeable decline in functioning in areas such as work or relationships since the onset of symptoms.
• Duration: Continuous signs must persist for at least 6 months, including at least 1 month of active-phase symptoms, which may be shorter if treated. Symptoms can also be prodromal or residual, including negative or attenuated active-phase symptoms.
• Exclusion Criteria: Schizoaffective, depressive, or bipolar disorders with psychotic features must be excluded. Symptoms should not be attributed to substance use, medication, or another medical condition. If a developmental disorder is present, the diagnosis requires at least 1 month of prominent delusions or hallucinations.

2. ICD-10

The ICD-10 specifies that the patient must demonstrate at least one of the following symptoms for a duration of 1 month or more:

• Thought echo, thought insertion or withdrawal, thought broadcasting
• Delusions of control, influence, or passivity; delusional perceptions
• Hallucinatory voices providing a running commentary on the patient or discussing the patient among themselves
• Persistent delusions that are culturally inappropriate or implausible

Alternatively, the patient may exhibit at least two of the following symptoms for 1 month or more:

• Persistent hallucinations in any modality, accompanied by fleeting or half-formed delusions
• Breaks or interruptions in thought leading to incoherence, irrelevant speech, or neologisms
• Catatonic behavior
• Negative symptoms
• Significant changes in overall behavior, such as loss of interest and social withdrawal

In contrast to the DSM-5-TR, the ICD-10 categorizes schizophrenia based on key presenting symptoms into various types, including:

• Paranoid schizophrenia
• Hebephrenic schizophrenia
• Catatonic schizophrenia
• Undifferentiated schizophrenia
• Post-schizophrenic depression
• Residual schizophrenia
• Simple schizophrenia
• Schizophrenia, other
• Schizophrenia, unspecified

Evaluation of Schizophrenia

Schizophrenia is primarily a Clinical diagnosis, but specific radiographic and laboratory tests are necessary to rule out other potential causes. The American Psychiatric Association Practice Guideline for the Treatment of Patients with Schizophrenia recommends the following evaluations during an initial assessment:

1. Hematology

A complete blood count (CBC) should be performed to check for anemia or signs of infection that may mimic schizophrenia symptoms. If the patient is being considered for treatment with clozapine, an absolute neutrophil count (ANC) should also be obtained.

2. Blood Chemistry Panel

This should include tests for electrolytes, renal function, liver function, and thyroid-stimulating hormone (TSH). Hypothyroidism can present with psychiatric symptoms such as depression and cognitive impairment.

3. Pregnancy Test

A pregnancy test is recommended for women of childbearing age.

4. Electroencephalogram (EEG)

An EEG may be warranted based on the neurological examination or patient medical history to rule out seizure disorders.

5. Imaging

Brain imaging tests, either a CT or MRI (with MRI being preferred), may be indicated based on neurological findings or patient medical history.

6. Genetic Testing

Chromosomal testing is suggested if indicated by the physical examination or developmental clinical history.

7. Drug Toxicology Screen

This screen may be necessary to identify substance use that could lead to psychotic symptoms.

Treatment of Schizophrenia

The treatment of schizophrenia typically involves a comprehensive approach that combines medication, psychotherapy, and supportive services. Here are the key components:

1. Medications

• Antipsychotics: These are the cornerstone of schizophrenia treatment. They can help manage symptoms such as delusions, hallucinations, and disorganized thinking. There are two main categories:
  • Typical (First-Generation) Antipsychotics: Examples include haloperidol and chlorpromazine. These primarily target dopamine receptors but may have more side effects, such as extrapyramidal symptoms.
  • Atypical (Second-Generation) Antipsychotics: Examples include risperidone, olanzapine, and aripiprazole. These tend to have a lower risk of motor side effects and can also address negative symptoms.

2. Psychotherapy

• Cognitive Behavioral Therapy (CBT): This can help patients manage symptoms and improve functioning by challenging distorted thoughts and developing coping strategies.
• Supportive Therapy: Providing emotional support, practical assistance, and education about the mental disorders can be beneficial.
• Family Therapy: Involving family members can enhance support and improve communication.

3. Rehabilitation and Support Services

• Psychosocial Rehabilitation: Programs focused on social skills training, vocational rehabilitation, and community support can help individuals reintegrate into society and improve quality of life.
• Case Management: Coordinated care by case managers can assist patients in accessing services and navigating the healthcare system.