Step 1 Content | Radiology

General Radiology/Imaging

- X-ray (plain film) – principles and indications - CT scan – contrast vs. non-contrast, cross-sectional anatomy - MRI – T1 vs. T2 weighting, functional MRI - Ultrasound – Doppler imaging, echogenicity - nuclear medicine – PET scan, bone scan - Fluoroscopy – dynamic imaging techniques

- Artifact recognition (motion, metal, beam hardening) - Contrast-induced nephropathy - Radiation exposure risks

Hematopoietic & Lymphoreticular

- Lymph node evaluation (CT, PET scan) - Bone marrow changes (MRI) - Splenomegaly assessment (ultrasound, CT)

- Lymphadenopathy (reactive, lymphoma, metastatic disease) - Bone marrow infiltration (leukemia, metastases) - Splenic rupture, infarction

Central & Peripheral Nervous

- CT for acute hemorrhage, stroke - MRI for demyelination, tumors - Angiography for vascular abnormalities - PET for metabolic brain activity

- Stroke (ischemic, hemorrhagic) on CT/MRI - Multiple sclerosis plaques on MRI (T2 hyperintensity) - Brain tumors (glioblastoma, meningioma) - Hydrocephalus (ventricular dilation)

Skin & Connective Tissue

- Soft tissue ultrasound for masses, infections - MRI for deep soft tissue lesions

- Cellulitis (soft tissue edema, enhancement) - Abscess (fluid collection with rim enhancement) - Soft tissue tumors (lipomas, sarcomas)

Musculoskeletal

- X-ray for fractures, arthritis - CT for complex fractures, bone tumors - MRI for soft tissue injuries, ligament tears - Bone scan for metastatic disease

- Fractures (simple, comminuted, stress) - Osteoarthritis (joint space narrowing, osteophytes) - Osteomyelitis (bone destruction, periosteal reaction) - Ligament and tendon tears (ACL, rotator cuff)

Respiratory

- Chest X-ray for pneumonia, effusions, lung masses - CT for interstitial lung disease, PE, lung cancer staging - MRI for mediastinal and hilar masses - Pulmonary angiography for PE

- Pneumonia (airspace opacities, consolidation) - Pulmonary embolism (filling defect in pulmonary arteries) - Lung cancer (spiculated nodule, mediastinal lymphadenopathy) - Pleural effusion (blunted costophrenic angle)

Cardiovascular

- Echocardiography (transthoracic, transesophageal) - Coronary CT angiography for CAD - Cardiac MRI for myocarditis, cardiomyopathies - nuclear stress test for ischemia

- Myocardial infarction (hypokinesis, perfusion defect) - Aortic aneurysm (dilated aortic diameter) - Valvular heart disease (stenosis, regurgitation) - congenital heart disease (tetralogy of Fallot, septal defects)

Gastrointestinal

- Abdominal X-ray for bowel obstruction, free air - CT for appendicitis, diverticulitis, pancreatitis - MRI for liver lesions, biliary obstruction - Barium studies for dysphagia, GERD - Endoscopic ultrasound for pancreatic/biliary disease

- Bowel obstruction (dilated loops, air-fluid levels) - Appendicitis (enlarged appendix, periappendiceal fat stranding) - Liver cirrhosis (nodular contour, ascites) - Gallstones (echogenic shadowing on ultrasound)

Renal/Urinary

- Ultrasound for kidney stones, hydronephrosis - CT for nephrolithiasis, renal masses - MRI for renal function assessment - Voiding cystourethrogram (VCUG) for reflux

- Kidney stones (radiopaque calculi on CT) - Hydronephrosis (dilated renal pelvis) - Polycystic kidney disease (enlarged kidneys with multiple cysts) - Renal tumors (hypervascular mass)

Reproductive

- Pelvic ultrasound for ovarian and uterine pathology - Mammography for breast cancer screening - Hysterosalpingography (HSG) for fallopian tube patency - Testicular ultrasound for masses, torsion

- Ovarian cysts, polycystic ovaries - Uterine fibroids (hypoechoic mass on ultrasound) - Breast cancer (spiculated mass, microcalcifications) - Testicular torsion (absent blood flow on Doppler)

Endocrine

- Thyroid ultrasound for nodules - Sestamibi scan for parathyroid adenomas - Adrenal CT/MRI for adrenal masses - Pituitary MRI for adenomas

- Thyroid nodules (solid, hypoechoic with microcalcifications) - Hyperparathyroidism (enlarged parathyroid gland on scan) - Adrenal adenoma (well-circumscribed, lipid-rich mass) - Pituitary adenoma (enlarged sella turcica)