Radiology Revision E6.5 PDF

Radiology Revision 1 01 1 RADIOLOGY REVISION 1 ----- Active space ----- Introduction to Radiations 00:00:10 Wilhelm Rontgen :...

Radiology Revision 1 01 1 RADIOLOGY REVISION 1 ----- Active space ----- Introduction to Radiations 00:00:10 Wilhelm Rontgen : Discovered X-rays. Symbols : Radiation hazard X-ray radiation Sealed radiation Trefoil : Fan with 3 leaves hazard source Electromagnetic spectrum : Increasing frequency and energy Radiowaves < Microwaves < Infrared waves < Visible light < UV rays < X-rays < Gamma rays The Electromagnetic spectrum Radiation units : Parameter Conventional unit SI unit Radiation exposure Roentgen Coulomb/kg Absorbed dose Rad Gray Absorbed dose equivalent Rem Sievert Radioactivity Curie Becquerel Effects of Radiation 00:09:15 Law of radiobiology/law of Bergonie & Tribondeau : Tissues with max. undifferentiated cells or cells in active mitosis are more radiosensitive. Acute Radiation Syndromes : Absorbed dose Acute Radiation syndrome Bone marrow 1-2 Gy Acute hematological syndrome cells are most 6-10 Gy Acute GIT syndrome radio sensitive. 20 Gy Acute CNS syndrome Radiology Revision v1.0 Marrow 6.5 2023  2 01 Radiology ----- Active space ----- Adverse effects of radiation on the body : Deterministic Effect Stochastic Effect Acute radiation syndromes. Carcinogenesis. Cataract. Mutations. Examples Skin effects. Chromosomal aberrations. Sterility. Onset Acute to subacute. Chronic. Threshold dose Present. Absent. Severity with an in radiation dose. No change with change in radiation dose. Radiation exposure 00:18:46 Color Radiation exposure Examples PET scan (25 mSv). Red (CT/PET/ CT abdomen (10 mSv). Radionuclides) High CT thorax (8 mSv). Note : Used with Bone scan. caution in children. CT head/brain (3.5 mSv). Ba enema (7 mSv), Ba meal follow Yellow (Diagnostic through, Ba meal, Ba swallow. Intermediate procedures) Intravenous urography. Micturating cystourethrogram (1.2 mSv). CXR PA view (0.02 mSv) : M/C used. Lumbar spine (1.0 mSv). Green (Spot Abdominal X-ray. Low (Safe) radiographs) Hip AP view. Skull AP. Limb/joint X ray (0.01 mSv). ICRP/ICRU radiation exposure guidelines : Public Occupational exposure exposure Max in 5 years : 100 mSv. Effective dose 1 mSv/year Allowed : 20 mSv/year averaged over 5 years. Max 50 mSv in any one year. Annual equivalent 15 mSv. 150 mSv. dose to lens of eye Annual equivalent 50 mSv. 500 mSv. dose to skin For pregnant Zero, but permissible dose of < 1 mSv. radiation workers Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 1 01 3 Note : ----- Active space ----- Accidental chest X-ray in a pregnant lady → Reassurance and continue pregnancy. Atomic Energy Regulatory Board (AERB) guidelines : Max exposure in a year is 30 mSv/year but maximum exposure in 5 years is 100 mSv. X-ray tube structure and functions 00:27:40 Working principle of X-ray tube : Thermionic emission. Types of emissions from anode : Continuous spectrum Characteristic spectrum Amount 70-80 % (M/c). 20-30 %. Emitted electron knocks out inner shell Kinetic energy lost from deflection/ electron creating a vacancy for outer Mechanism deceleration of electrons is shell electron to jump in and the energy converted to X-ray. lost is converted as an x-ray. Uses Most of the radiological procedures. Mammography. Note : Continuous spectrum radiation is also called as braking radiation/white radiation/Bremsstrahlung radiation. Interactions of X-rays with matter : 00:35:20 Compton v/s Photoelectric Effect : Compton effect (M/C) Photoelectric effect (2nd M/C) Aka Mid energy phenomenon. Low energy phenomenon. Deviation of x-ray photon (Scatter MOA of Absorption of X-ray photon by the inner radiation) as it strikes the outer effect shell electron. shell electron. Applied Causes image distortion → So, Improves image quality/contrast → So, aspect minimize Compton effect. maximise Photoelectric effect. Exposure factors 00:40:49 Kilo voltage peak (kVp) : Peak potential difference between cathode and anode. Determines : Penetration of the X-ray beam (Directly proportional). Image contrast (Inversely proportional). Radiology Revision v1.0 Marrow 6.5 2023  4 01 Radiology ----- Active space ----- Milliampere-second (mAs) : Current passing through the X-ray tube for a set duration of time. Determines → Film blackening or contrast (Directly proportional). Thermoluminescent Dosimeter (TLD) badge : Department personnel radiation exposure monitoring device. TLD Badge Computed Tomography (CT) 00:48:11 Founding father of CT : Sir Godfrey Hounsfield. Lining of the equipment room : 1/16th inch of lead all around (Or) 4-6 inches of concrete. Hounsfield unit/CT value scale : Acute Air Lungs Fat Water bleed Bone -1000 -800 -100 0 +45 to +65 +1000 Less dense More dense CT Scale Total HU : 2000 shades of grey. CT Polytrauma/whole body CT/Pan-scan : Standard protocol : Non contrast CT of the head + cervical spine. Contrast enhanced CT of the chest + abdomen + pelvis. Note : Body part not included in the protocol → Limbs. Ultrasonogram 00:57:01 Ultrasonic : > 20,000 Hz. Ultrasound spectrum in diagnostic practice : > 1 mega Hz. USG basic principle : M/c piezoelectric crystal : Lead zirconate titanate. Reverse piezoelectric effect : Electric current passing through the crystal produces vibrations in the tissues. Piezoelectric effect : Vibrations reflected by tissues are converted back into electric impulses. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 1 01 5 Magnetic Reasonance Imaging 01:00:35 ----- Active space ----- Basic principle : Gyromagnetic property of hydrogen nucleus (Strongest gyromagnetic property). Contraindications of MRI : Absolute Relative 1. Cardiac pacemaker. 1. Claustrophobia (Can be performed after sedation). 2. Cochlear implant. 2. Devices : Insulin pumps/nerve stimulators, epidural 3. Metallic foreign body in the eye. catheters, prosthetic heart valves. 4. Ferromagnetic CNS aneurysm 3. 1st trimester of pregnancy (Loud noise while scanning clips. → May cause deafness in the developing fetus). Note : Faraday’s cage : Copper wires wrapped around wooden panels to prevent the magnetic field from interacting with outside environment. Contrast Media 01:07:05 X-rays/CT : Barium and iodine. USG : Stabilised microbubbles. MRI : Gadolinium (M/c). Barium : Ba swallow Ba meal Ba meal Ba enema follow through C/I of barium as a contrast media : Absolute : Perforation of organs → Severe chemical peritonitis/mediastinitis. Relative : a. Hypersensitivity. b. Suspected tracheo-esophageal fistula (TEF). c. Vesicovaginal fistula (VVF). d. Vesicorectal fistula. e. Fecoliths. Radiology Revision v1.0 Marrow 6.5 2023  6 01 Radiology ----- Active space ----- Iodinated contrast : Classification of iodinated contrast : Iodinated contrast media High osmolar Low osmolar Ionic Ionic Non-ionic Non-ionic monomers dimers monomers dimers Worst contrast d/t M/c iodinated Best contrast low IP ratio contrast d/t high IP ratio IP Ratio 3:2 6:2 3:1 6:1 Urograffin Ioxaglic acid Amipaque Iotrol Gastrograffin Iohexol /Omnipaque Iotrolan (m/c) Iodixanol Iopamidol Ioversol Contrast induced nephropathy (CIN) : Markers of CIN : Serum creatinine : ↑ in serum creatinine by 25% from the pre-injection value or > 0.5 mg/dL within 48-72 h of contrast injection. Serum cystatin C. eGFR (< 60 mL/min). Neutrophil Gelatinase-Associated Lipocalin (NGAL) : Novel marker. Risk factors of CIN : Increased age. Hypovolemia. Chronic HTN. Dehydration. Diabetes Mellitus. Multiple myeloma. Metabolic syndromes. Pre-existing chronic kidney disease : Single Anemia. most important patient related risk factor. Management : Self limiting condition → Supportive treatment (Fluid and electrolytes). Very severe cases → Hemodialysis. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 1 01 7 Prevention : ----- Active space ----- Always perform precontrast RFTs before injecting contrast. Pre-hydrate the patient. N-acetyl cysteine therapy. Rosuvastatin, Vitamin C and bicarbonate therapy. MRI contrast agents : 01:20:50 T1 relaxation T2 relaxation agents agents Example Gadolinium (M/c). Super paramagnetic iron oxide (SPIO). MRI sequence Bright on T1W. Dark on T 2 w. Comments C/I in pregnancy. Used to detect Kupffer cell activity (Focal nodular hyperplasia). Hepatocyte specific contrast agents : Gd–Manganese DPDP. Mangafodipir trisodium. Gd–BOPTA. Gd–EOB-DTPA. MRI contrast adverse effects : Nephrogenic systemic fibrosis (NSF). M/c seen in chronic kidney disease. Also caused by : Omniscan/Gadodiamide (Banned now). Radiology Revision v1.0 Marrow 6.5 2023  8 02 Radiology ----- Active space ----- RADIOLOGY REVISION 2 Nuclear Imaging 00:00:57 Radionuclide scan : A radio-nuclide is administered I/V → Emitted radiations are then detected with gamma cameras. Thyroid gland Depending upon the detection of radiation, they are classified into 1. Planar scintigraphy : Single gamma camera from only one plane. 2. SPECT (Single Photon Emission Computed Tomography) : Multiple gamma cameras from multiple planes. Has better sensitivity. Good anatomical and spatial resolution. Co-incidence of signals Gamma ray photons Annihilation reaction Planar scintigraphy SPECT Co-incidence imaging 3. PET (Positron Emission Tomography) : Used for cancer imaging. M/C radio isotope used : 18-flourodeoxyglucose (18-FDG). GLUT type 1 is overexpressed in cancer cells → 18-FDG is phosphorylated & trapped in cancer cells (D/t Warburg effect → ↑ Glucose uptake). Co-incidence imaging : Positron (18-FDG) collides with electron (Normal tissue) → Annihilation → Release 2 gamma ray photons in opposite directions which coincide perfectly → Single point source of emission → Detected by ring of detectors. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 2 02 9 Color coding of PET scans : ----- Active space ----- High metabolic activity ( FDG uptake) : Red, yellow. Low metabolic activity ( FDG uptake) : Blue, green. Errors in PET scan : False Negative False Positive 1. Tumor < 1 cm. Infection/Inflammation : 2. Low grade malignancies : Granulomatous conditions. Typical carcinoid. Cellulitis. Bronchoalveolar Carcinoma. Abscess. Lung metastasis from mucinous extrapulmonary tumour. Tumours treated with chemotherapy. 3. Hyperglycemia (competition to uptake of FDG). Radioisotopes used in Various Nuclear Imaging 00:13:15 Technetium-99 : M/c isotope used in nuclear medicine as it is easily adherent to any molecule/ cell/particle. Synthesized from Tc-99m Degenerates into Tc99 Molybdenum-99 (Metastable isomer) Ruthenium-99 t1/2 : 6 hrs Gallium-67 scan : T1/2 : 78 hrs. Sensitive for detection of infection/inflammation (Pyrexia of unknown origin) but not specific (False positive seen in sarcoidosis & lymphoma). Leucocyte tagging increases specificity of Gallium-67. Renal Imaging : 00:18:50 1. Static (Structural / Anatomical evaluation) : Tc-99m DMSA (DiMercapto Succinic Acid). IOC in Cortical scars in Vesico Ureteric Reflux, Ectopic kidney. 2. GFR estimation : Tc-DTPA (Excreted exclusively by glomerular filtration). 3. Dynamic/renal function evaluation : Tc-Mag3 (Mercaptoacetyltriglycine) → Glomerular filtration & tubular secretion. Radiology Revision v1.0 Marrow 6.5 2023  10 02 Radiology ----- Active space ----- 4. Renal artery stenosis (RAS) : Captopril Tc 99m-DTPA scan. In RAS, Captopril causes efferent arteriolar dilatation → Fall in GFR → Renal failure. Captopril Tc 99m-DTPA scan is done before (Baseline : GFR1) and after (Repeat : GFR2) administration of a small dose of the Captopril. If GFR2 < GFR1 → Renal artery stenosis. Tc99m-DTPA Tc99m-DTPA scan scan (Baseline) Small dose of (Repeat) captopril Cardiac Imaging : 00:24:45 1. Cardiac perfusion/Capillary blood flow Imaging : Thallium 201 : Behaves like K+ & is more in intracellular space. Normal cardiac cells : Hotspot. Infarct : Cold spot (No perfusion). 2. Infarct imaging /Infarct Avid imaging : 99m Tc- Stannous pyrophosphate. Infarct : Hot spot. 3. Radionuclide Ventriculography : MUGA scan (Multiple Gated Acquisition scan) with 99m Tc- RBCs. Cardiac function assessment : Stroke volume & cardiac output can be calculated through EDV & ESV. 4. Myocardial Viability Assessment : Normal cardiac tissue : Source of energy is fatty acids (No uptake of FDG). Ischemic tissue : Source of energy is glucose. 18-FDG PET will show increased uptake in ischemic tissue. 00:24:45 Lung Imaging : Ventilation (V) - Perfusion (Q) scan : Was used for diagnosis of pulmonary embolism (Not used presently). Ventilation : 99mTc-Aerosols. Perfusion : 99mTc-Macroaggregated albumin. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 2 02 11 Normal V/Q = 1. ----- Active space ----- Early Pulmonary embolism (PE) : Perfusion = ↓ or absent ; Ventilation = Normal, V-Q scan → Mismatched defect. In advanced PE (Lung infarction) : Triple match → Both V & Q ↓ and Chest X-Ray show consolidation. GI Tract Imaging : 00:31:46 Radionuclide scan : High sensitivity. Threshold rate for detection of bleeding : 0.05 to 0.1 mL/min. 99m Tc Sulfur colloid 99m-Tc-RBCs 99m-Tc-pertechnate Detects active GI bleed. Detects intermittent GI IOC for Meckel’s diverticulum (Has bleed. affinity for gastric mucosa) Biliary Tract Imaging : 00:33:50 Hepatic Imino Di-Acetic Acid (HIDA) scan : I/V HIDA → Taken up by hepatocytes → Secreted into bile. Structures visualised : Right, left and common hepatic ducts; gall bladder (GB), cystic duct, common bile duct (CBD), duodenal opening of the CBD. Non visualisation of GB in HIDA : Acute cholecystitis. Skeletal Imaging : 00:35:42 99M Tc-MDP (Methyl DiPhosphate) Bone scan : MDP acts like bisphosphonate by binding to osteoclasts. Super scan : Excessively high uptake of 99m Tc-MDP in the skeletal system. No uptake in soft tissue/kidney/bladder. Seen in hyperparathyroidism, renal failure, Paget’s disease, metabolic bone disease. Super scan Neck Imaging : 00:37:31 Thyroid Nodule imaging : 99mTc-pertechnate/1-123 Na-iodide : Used to image thyroid nodules. Radiology Revision v1.0 Marrow 6.5 2023  12 02 Radiology ----- Active space ----- Cold nodule Warm nodule Hot nodule No uptake of radionuclide Uptake in nodule is similar to Uptake in nodule > normal in nodule. normal thyroid gland. thyroid gland. Highest malignant potential Least malignant potential Intermediate risk of malignancy. (20%). (2%). Therapeutic uses of radioactive iodine : Iodine-131 : Papillary thyroid cancer. Iodine-125 : Brachytherapy (not commonly used). Thyroid isotopes used in PET scan : Iodine-124. Non-radioactive Iodine isotope : Iodine-127. Parathyroid imaging : 99mTc-SestaMIBI scan/99mTc-Tetrofosmin scan : IOC for parathyroid localisation : 99mTc -SestaMIBI scan. IOC for parathyroid tumors : 4D CT (Axial + Coronal + Sagittal plane + Contrast enhanced). Salivary gland imaging: 99mTc-pertechnate scan : Taken up by normal tissue & not taken up by tumour tissue. All tumors appear ‘coldspot’ except Warthin’s tumor/Adenolymphoma of salivary gland (hotspot). Neuroendocrine (NET)/catecholamine producing tumor imaging I-131 MIBG (Meta-Iodo-Benzyl-Guanidine) scan : Used in Pheochromocytoma, Medullary thyroid cancer, neuroblastoma, ganglioneuroma, ganglioneuroblastoma. NETs express somatostatin receptors (SSTR) → SSTR analogues are used for detecting NETs. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 2 02 13 Note : ----- Active space ----- IOC for adrenal pheochromocytoma : Contrast enhanced MRI. IOC for extra-adrenal pheochromocytoma : DOPA-PET Scan (Ga68- DOTATATE PET CT). Radiation Components 00:44:43 ALPHA BETA X-RAY GAMMA Max. damage M/c used Min. damage Min. penetration Max. penetration Ionizing/Damaging power decreases; Penetrating power increases Intranuclear Intranuclear Extranuclear Intranuclear origin origin origin origin Radium-223 : Phosphorus-32 : Technetium 99m : Rx of bone Rx of : Diagnostic metastasis (mets) Polycythemia purpose. Radon-222 : rubra vera. Cobalt-60 : Contaminator Bone mets. Therapeutic Causes lung Strontium-89 : purpose. cancer Rx of Bone mets (best isotope) Yttrium-90 : Trans-arterial chemoembolisation (TACE) of hepato- cellular cancer Bragg’s peak : Entire energy is deposited (Maximum dose delivery) at a single point. Seen in heavy & charged particles ( α and protons). Bragg’s peak Radiology Revision v1.0 Marrow 6.5 2023  14 02 Radiology ----- Active space ----- Radiotherapy 00:50:15 Mechanisms of damage : Direct : Ionisation (First step) → dsDNA breaks → Cell death. Indirect (M/C) : Action on intracellular H2O → Forming superoxide. Fractionated radiotherapy : The total dose required is split into multiple fractions & then administered to pt. Fractionated radiotherapy Hypofractionation Conventional fractionation Hyperfractionation (M/C) 1 fraction/ day For palliative care, Monday to Friday. For aggressive tumors : Soft tissue sarcoma, Weekend holiday. Cerebral glioma, small cell Melanoma. Not preferred for lung cancer, head & neck aggressive tumors. and face cancer. Radiotherapy - Cell sensitivity : G2 Maximum radiosensitivity is at the G2-M junction M or at M phase. Cell phase S Minimum radiosensitivity is at the S phase. cycles G1 Radio-sensitivity of tumors : Least sensitive (MOP) Most sensitive (WELMS) Wilm’s Tumor. Melanoma. Ewing’s sarcoma. Osteosarcoma. Lymphoma. Pancreatic Ca. Myeloma. Seminoma. The 5 R’s of Radiotherapy: Radiosensitivity. Reoxygenation. Repair. Reassortment. Repopulation. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 2 02 15 Types of Radiotherapy : ----- Active space ----- 1. External Beam Radiotherapy (EBRT)/Teletherapy (M/C) : Radiation source is at a distance from the patient’s body. Two types : a. Cobalt-60 machines : M/c used in past. t1/2 = 5.2 years. Cobalt-60 : Artificial isotope. Cobalt-60 machine Note : Naturally occurring Co isotope : Co-59 (non radioactive). b. Linear Accelerators (LINAC) : de High energy X-rays + e- are produced. d s ano ar Easy to control and use. e d tow rat le cce e- a Disadvantage of EBRT: Normal tissue lying in the path of beam is exposed to radiation. 2. Brachytherapy : LINAC Radiation source placed inside/on the tumor. It reduces the exposure to normal tissue. Types : Brachytherapy Interstitial Intra-cavitory Mould Systemic type Isotope placed Radiation source Radiation source IV injection inside tumour is placed inside is placed on the of an isotope tissue. a naturally surface of the which gets Features Under transrectal occurring body body/tumor. concentrated USG guidance and cavity in the target Remote organ. afterloading. Iodine-131 in Ca penis, SCC of Examples Ca prostate Ca cervix papillary thyroid tip of finger. cancer. Intra-cavity brachytherapy Mould brachytherapy Interstitial brachytherapy Radiology Revision v1.0 Marrow 6.5 2023  16 02 Radiology ----- Active space ----- Special Applications of RT : Intra-operative RT: Given during Surgical excision of tumors where approach is difficult. Intraoperative irradiation of tumour bed by Electron beam (or) X-rays. E.g. : Ca. Pancreas. Stereotactic radiosurgery and Intensity modulated radiotherapy Stereotactic radiosurgery/Gamma Intensity Modulated Radiotherapy knife surgery (IMRT) Multiple beams (uniform strength) Multi-directional beams with beamlets from multiple directions are focussed of different strengths that can be on the tumour. adjusted based on tumour dimension. Uses : Brain tumours, vestibular Use : Ca prostate. schwannoma, pituitary adenoma, trigeminal neuralgia, metastasis & AV malformations. IMRT Stereotactic radiosurgery Emergency radiotherapy : Indications : Superior vena caval compression. Spinal cord compression. Pericardial neoplastic tamponade. Increased intracranial tension d/t metastasis. Hypercalcemia/tumor lysis syndrome. Cranio-spinal irradiation : Used to treat or prevent the spread of tumor. Indicated in aggressive tumours : a. CNS : Medulloblastoma, glioblastoma multiforme, germinoma. b. Non-CNS : Acute Lymphoblastic Leukemia, Small cell lung cancer, Non-Hodgkin lymphoma. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 3 03 17 RADIOLOGY REVISION 3 ----- Active space ----- CXR views 00:00:31 Postero-anterior (PA) view Antero-posterior (AP) view M/c CXR view. Done in neonates/critically ill patients. Direction of x-ray beam : Posterior to Anterior to posterior of the patient. anterior of the patient. Tube to film distance : 6 feet/72 Tube to film distance : Less. inches/180 cm. X ray beam centered at inferior angle Divergent X ray beam. of scapula/T8 body/T7 spinous process. Heart size : Normal False cardiomegaly is seen. Techniques of x-ray projection : kVp (Kilovoltage peak) is inversely proportional to image contrast. kVp is directly proportional to penetrating power. Low kVp technique High kVp technique 60-80 kV. 120-170 kV. High contrast film. High penetrating x-ray beam. Use : Use : Miliary shadows. Obese patients. Calcifications. To look for hidden areas. CXR Standard technique : 1. PA view. 2. Erect position (If unable : Sitting). 3. Suspended end inspiration. Radiology Revision v1.0 Marrow 6.5 2023  18 03 Radiology ----- Active space ----- Exceptions : Indications of expiratory view : Pneumothorax. Foreign body aspiration (D/t air trapping). Obstructive lung disorders : Chronic bronchitis, emphysema. Diaphragmatic palsy. Other CXR views : Lateral CXR view : Normal findings : Posterior costophrenic recess : a. Most dependent part of Costophrenic pleural cavity. recess b. Fluid collection in pleural effusion. CXR findings on lateral view Lateral decubitus view : Most sensitive radiograph for minimal pleural effusion : Left lateral decubitus view. IOC for minimal pleural effusion : USG. Pleural effusion on left decubitus view Posterior oblique view : Right & left. To visualize : I/L rib fractures. Lordotic view : To visualize : Middle lobe pathologies. Apicogram : To visualize : Lung apices. Lordotic view/Apicogram Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 3 03 19 Note : ----- Active space ----- Conditions with USG as IOC (D/t fluid accumulation) : Pleural effusion. Pericardial effusion (Echocardiography). Ascites. Conditions with CT as IOC (D/t air accumulation) : Pneumothorax. Pneumomediastinum. Pneumoperitoneum. Retroperitoneal organs (Pancreas). Normal CXR interpretation 00:17:40 1. Identification of ribs : Location of ribs : Posterior ends : Closer to midline. Anterior ends : Away from midline. Orientation : Posterior ends : Horizontal. Anterior ends : Oblique. Criteria for X-ray taken in adequate inspiration : Posterior ends : Minimum 10 ribs visible Anterior end of Posterior end of rib above diaphragm. rib (Vertical) (Horizontal) Anterior ends : Minimum 6 ribs seen Adequate inspiratory radiograph above diaphragm. 2. Cardiomegaly assessment : Objective measurement : Cardiothoracic ratio : Max transverse diameter of heart (A) Max transverse diameter of inner thorax (B) In PA view : a. < 0.5 : Normal. b. 0.5-0.55 : Borderline. c. > 0.55 : Cardiomegaly. Cardiothoracic ratio parameters In AP view : a. Normally : False cardiomegaly present. b. > 0.60 : Cardiomegaly. Radiology Revision v1.0 Marrow 6.5 2023  20 03 Radiology ----- Active space ----- 3. Mediastinal margins : Aortic knuckle SVC Main pulmonary artery Lt atrial append- RA age IVC Lt ventricle Right mediastinal margin Left mediastinal margin 4. Hilum : Superior pulmonary veins Hilar point (Lt higher) Lower lobe pulmonary artery 5. Diaphragm : Cardiophrenic angle Costophrenic angle Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 3 03 21 6. Hidden areas : ----- Active space ----- Five hidden areas : a. Lung apices. b. Mediastinum & hila. c. Retrocardiac lung. d. Lungs in posterior deep recesses. e. Lungs overlapped by bones. Visualized by high kVp CXR. Hidden areas Prosthetic valves on CXR 00:37:33 PA view Lateral view Incidentals on CXR 00:40:26 1. Dextrocardia with situs inversus : A/w Kartagener syndrome (Primary ciliary dyskinesia) : Bronchiectasis. Sinusitis. Dextrocardia with situs inversus. Infertility. Dextrocardia Gastric bubble Radiology Revision v1.0 Marrow 6.5 2023  22 03 Radiology ----- Active space ----- 2. Cervical rib : Extra rib articulating with the tran- verse process of a cervical vertebra. C7 transverse process Asymmetrical. Significance : Thoracic outlet syn- T1 transverse process drome. Cervical rib Cervical rib 3. Scoliosis : Lateral curvature of spine. Measured by Cobbs angle. Cobbs angle : Angle b/w the perpendic- ulars drawn to the lines from the cranial most and the caudal most scoliotic vertebra. Cobbs angle 4. Ca breast : Findings : Right breast shadow present. Left breast shadow missing : S/o post mastectomy. Most likely points to Ca breast. Absent left breast shadow Post mastectomy film 5. Pneumoperitneum 6. Pseudo pneumoperitoneum Clinical features : Abdominal pain & Clinical features : discomfort. a. Asymptomatic with only x-ray findings : K/a Chilaiditi sign. b. Symptomatic : K/a Chilaiditi syndrome. Xray findings : Lucency (D/t free Xray : Lucency below the dome with air) below the dome of diaphragm. bowel wall markings (Not free air). M/c cause : Bowel perforation. Cause : Trapped transverse colon Management : Emergency (hepatic flexure) b/w diaphragm & liver. exploratory laparotomy. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 3 03 23 ----- Active space ----- Air (lucency) under diaphragm Bowel wall markings under diaphragm Pneumoperitoneum Pseudo pneumoperitoneum Silhouette sign 00:47:33 Positive silhouette sign : Obscuration of sharp borders when the adjacent tissues are of similar densities. Right heart border obscured (d/t RML consolidation) : Positive silhouette sign. Normal cardiac silhouettes & lobar anatomy : Oblique fissure Anterior segment LUL Apico posterior segment of of RUL LUL (Aortic knuckle) (Rt paratracheal RUL border) Sup & post. basal segment of LLL (Lateral margin of RML RML descending thoracic aorta) (Rt heart border) Lingular segment of LUL RLL> RML LLL (Left heart border) (Right dome of diaphragm) LLL (Left dome of diaphragm) Radiology Revision v1.0 Marrow 6.5 2023  24 03 Radiology ----- Active space ----- Air bronchogram sign 00:56:32 M/c associated with infective consolidation (Non specific). Findings : Opacity in the lungs. Black branching lines through the opacity. Other causes of air bronchogram : Pulmonary edema. Interstitial lung disease. Bronchoalveolar ca. Pulmonary lymphoma. Pulmonary infarct. Pulmonary hemorrhage. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 4 04 25 RADIOLOGY REVISION 4 ----- Active space ----- Clinical Scenarios 00:00:52 Case 1 : History : A child with fever, cough with expectoration, breathlessness, on Rx with antibiotics. X-ray : Single/multiple air filled cystic lucency → pneumatoceles. Diagnosis : Staphylococcal pneumonia. Note : Community acquired pneumonia : M/C cause is streptococcus/pneumococcus (No pneumatocele). Pneumatocele Case 2 : History : Chronic alcoholic/debilitated patient with fever, cough with expectoration, breathlessness. X-ray : Consolidation of right upper lobe with bulging of the horizontal fissure → bulging fissure sign. Diagnosis : Klebsiella pneumonia. Cavitation is also seen in K. pneumonia. Bulging fissure sign Case 3 : History : Atypical presentation. a. Less prominent signs of LRTI. b. More prominent constitutional symptoms like headache, myalgia. X ray : Atypical findings. a. Diffuse interstitial thickening. b. Reticulonodular pattern of consolidation. Atypical pneumonia Diagnosis : Atypical pneumonia ( M/C cause → Mycoplasma pneumonia). Case 4 : History : k/c/o HIV, CD 4 PET-CT. Most of them are usually benign Popcorn calcification Coarse (popcorn) calcification : Pulmonary hamartoma Lung Tumors 00:54:47 1st investigation : CXR. IOC : CECT (Exception : Pancoast tumor). Corona radiata appearance : Spiculated appearance d/t invasion of tumor into the lung parenchyma. Corona radiata Radiology Revision v1.0 Marrow 6.5 2023  36 04 Radiology ----- Active space ----- Pancoast tumor : History : Elderly male, chronic smoker. C/F : a. Cough + hemoptysis. b. Left sided Horner’s syndrome : Cervical sympathetic ganglion invasion. c. Left upper limb : Pain, paresthesia & weakness (Brachial plexus invasion). Pancoast tumor CXR : Apical mass lesion with destruction of ribs. IOC : Contrast enhanced MRI (To look for neural invasion). Cannon ball metastasis in lungs : D/d for cannon ball metastasis : Renal cell cancer (M/C origin). Choriocarcinoma. Germ cell carcinoma. Endometrial carcinoma. Prostate carcinoma. Other lung conditions 00:58:45 Bronchiectasis : C/f : Cough with expectoration. Intermittent hemoptysis. Recurrent chest infections. X-ray : 1st investigation. Dilated bronchi on CXR Multiple thick walled cystic areas → Dilated bronchi. CT scan : IOC. Signs : Cluster of grapes sign. Tram track sign. String of beads sign. Signet ring sign. HRCT Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 4 04 37 Sarcoidosis : ----- Active space ----- C/f : Mild cough & weight loss. Lab findings : ↑sed ACE levels. Imaging : Chest X ray & CT chest shows : Egg shell calcification of LN. Bilateral hilar & right paratracheal lymphadenopathy. 1 2 CXR CT chest Gallium scan : 1. Panda sign 2. Lambda sign. Causes of egg shell calcification : SLAB of Calcium S Sarcoidosis, Silicosis, Scleroderma L Lymphoma (Post Rx) A Amyloidosis B Blastomycosis, fungal infections (Histoplasmosis) Calcium Coal worker’s pneumoconiosis Foreign body : History : A child with acute onset respiratory distress. Diagnosis : Foreign body aspiration. M/C aspirated foreign body : Peanut/groundnut (Not visualised on CXR). CXR : Air trapping in the affected lung. Air trapping in lungs Foreign body in trachea : Foreign body in esophagus : Severe respiratory distress, inspiratory stridor, Less respiratory distress, dysphagia +nt , FB in sagittal plane. FB in coronal plane Radiology Revision v1.0 Marrow 6.5 2023  38 04 Radiology ----- Active space ----- Imaging in heart conditions 01:06:43 Congenital heart anomalies : Disease Apperance on x-ray Transposition of Great Egg on side/egg on string appearance. Arteries (TGA) Tetralogy of Fallot Boot shaped heart/Coeur-en-sabot appearance. Total Anomalous Snowman/figure of 8 appearance. Pulmonary Venous (Specific for Type 1 TAPVC) Circulation (TAPVR) Ebstein’s anomaly Box shaped heart. Partial Anomalous Schimitar sign/turkish sword. Pulmonary Venous Circulation Egg on side/egg on string Boot shaped heart/Coeur- Box shaped heart appearance. en-sabot appearance. Snowman/figure of 8 appearance Turkish sword/Schimitar sign Schimitar syndrome/Hypogenetic lung syndrome : Right lung hypoplasia. Hypoplastic right pulmonary artery with anomalous supply from aorta. Schimitar vein (Anomalous pulmonary vein drains into IVC).. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 4 04 39 Coarctation of aorta : ----- Active space ----- M/C site : Distal to the site of origin of subclavian artery. Figure of 3 sign : Inferior rib notching sign/Roesler’s sign Dilated portions proximal and D/t the origin of collateral arteries from proximal distal to the coarctation. dilated arteries. M/C arteries involved in collateral formation : Inter- nal mammary artery & intercostal arteries. Mitral Stenosis 01:10:50 Chest X-ray findings : D/t left atrial enlargement. 1. Fullness beneath the pulmonary artery shadow : Earliest finding. 2. Elevated left bronchus + splaying of carina >90°. 3. Straightening of left heart border. 4. Third Mogul sign : Prominences around atrium (Aorta + Main pulmonary artery + left atrial appendage). 5. Double density sign : LA enlargement. 6. Walking man sign (Seen in lateral view) : Left bronchi pushed posteriorly. 3 5 4 Normal RA Enlarged LA Radiology Revision v1.0 Marrow 6.5 2023  40 04 Radiology ----- Active space ----- Congestive heart failure : CXR staging : Stage 1 Stage 2 Stage 3 PCWP 13-18 mm of Hg 18-25 mm of Hg > 25 mm of Hg X-ray Cephalization of blood Interstitial edema. Alveolar edema. signs flow/stag antler sign/ Kerley B line : Hori- Bat-wing opacities hands up sign/inverted zontal lines (D/t (Central perihilar moustache sign : Back thickening of deep opacities). pressure on superior pul- interlobular septae). monary vein (Upper lobe hilar vessels). Pericardial effusion : IOC : Echocardiography. Money bag/flask shaped/water Oreo cookie sign on lateral view : bottle appearance on CXR. Effusion separates pericardial & epicardial fat. Aortic dissection : Investigations : a. Emergency : Trans-esophageal echocardiography (TEE). b. IOC : CT Angiography (preferred)/MR Angiography. c. Gold standard technique : Invasive angiography. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 4 04 41 ----- Active space ----- Aortic dissection : Intimal flap divides Stanford A Stanford B : lumen into false & true lumen DeBakey I DeBakey II DeBakey III. Classification of Aortic dissection : 1. DeBakey system. 2. Stanford system. Signs : Cobweb sign Beak sign Aortic aneurysm : Abnormal focal dilation aortic lumen. Absolute cut off : Ascending aorta >5 cm in diameter. Descending aorta >4 cm in diameter. Abdominal aorta >3 cm in diameter. M/C site: Abdominal aorta (Infrarenal location). X ray CT chest Radiology Revision v1.0 Marrow 6.5 2023  42 04 Radiology ----- Active space ----- Signs of impending rupture : a. Crescent sign. b. Draped aorta sign. Crescent sign : Draped aorta sign Hyperdense blood clot Aorta draped around ventricle Note : in aneurysm size >10 mm/year is a sign of rupture. Pulmonary embolism : C/F : Sudden onset breathlessness, cough and hemoptysis. ECG : S1Q3T3 pattern. CXR : Normal. CECT : Clot inside the main pulmonary artery. main pulmonary artery Embolus Polo Mint sign : Central filling defect in artery. Suspected pulmonary embolism : D-dimer test : Screening test (High negative predictive value). CT angiography : IOC. V/Q scan : Not used. Invasive pulmonary angiography : Gold standard. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 4 04 43 Chest X-ray findings : ----- Active space ----- Pulmonary signs : a. Hampton’s hump : wedge shaped pulmonary infarct. b. Melting ice cube sign : Pulmonary infarct resolution from periphery to center. Vascular signs : Hampton’s hump a. Fleischner’s sign : Enlarged right main pulmonary artery. b. Palla’s sign : Enlarged right descending pulmonary artery. c. Chang’s/Knuckle sign : Enlarged right descending pulmonary artery with an abrupt cut off. Westermark sign : Focal oligemia in lung fields. Agatston score : Semi quantitative method. Obtained from CT of the coronary arteries. Assesses the calcium burden on coronary arteries. Weighted density score = HU score x Volume of calcification. Score : 101-400 : Moderate. >400 : Poor prognosis. Radiology Revision v1.0 Marrow 6.5 2023  44 05 Radiology ----- Active space ----- RADIOLOGY REVISION 5 CT vs MRI 00:00:09 CT is done when time for diagnosis is crucial. E.g. Stroke, head trauma. MRI is best image if there is no time constraints. Indications for MRI : Brain tumor. Multiple sclerosis. Developmental delay. Demyelinating disorders. Convulsion 1 week back. Imaging in Stroke 00:02:23 1st investigation in acute stroke → CT (R/o hemorrhage). Overall best/IOC for acute stroke : DWI-MRI (Detects infarct/ischemia). Penumbra in ischemia can be detected by PWI-MRI Rx :Thrombolysis. If hemorrhagic stroke detected on CT → Mx of bleed. IOC for vascular imaging in stroke : CT Angiography/TOF (Time of flight) MR Angiography. Ischemic stroke : Hyperacute stage : < 3-6 hrs. DWI ADC (a) (b) DWI with ADC map : Restricted diffu- On CT : sion. a. Hyper dense MCA (Middle cerebral artery) sign. b. Disappearing basal ganglia sign (Lt side). Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 5 05 45 Acute stage : ≥ 6 hrs. ----- Active space ----- 1. MCA territory infarct : Wedge shaped diffuse hypodensity (Oedema) Loss of grey-white differentiation. +ve cortical clinical signs : Aphasia, agnosia, etc. Acute right MCA territory Mass effect : Compression of ventricles and infarct. midline shift. 2. Lacunar infarcts : Involvement of basal ganglia or brainstem. Blockage of feeding artery → Lacuna shaped. No cortical clinical sign. Acute right basal ganglia Hemorrhagic stroke : lacunar infarct. Acute hypertensive bleed : Hyperdense bleed within basal ganglia + Rim of edema around. M/C site of hypertensive bleed : Putamen >Thalamus >Pons. Subarachnoid Hemorrhage : Clinical features : Thunderclap headache/worst headache. Becomes unconscious. CT finding : Hyperdensity (Blood) in basal cistern. Pathology : Rupture of Berry aneurysm. Poor prognosis. Other important conditions 00:15:28 Condition Image 1. Vein of Galen malformation : New born with high output CHF. Clinical features : Enlarged fontanelle, loud cranial bruit. CT finding : Dilated vein extending from straight sinus → Confluence of sinuses. Radiology Revision v1.0 Marrow 6.5 2023  46 05 Radiology ----- Active space ----- Condition Image 2. Periventricular leukomalacia : Cause : Hypoxic ischemic encephalopathy (HIE) in preterm babies. Clinical features : Seizures. CT finding : Periventricular hypodense changes with ventricular dilatation. 3. Posterior reversible encephalopathy syn- drome (PRES) : Cause : Severe pre-eclampsia. MRI-FLAIR (Fluid attenuated inversion recovery) : Hyperintensities in the parieto-occipital lobe. Completely reversible. 4.Venous sinus thrombosis : Presents with severe persistent headache and vomiting. Thrombosis of superior sagital sinus : (a) and (b) Note : Thrombosis of transverse sinus shows Cord sign (NCCT). (a) On NCCT : Delta sign. (b) On CECT : Empty delta sign. (Only walls of sinus enhanced). 5. Global cerebral hypoperfusion : Following cardiac arrest/hypotension. (a) Indicates : Brain dead state. Poor prognosis. CT findings : a. Reversal sign. (b) b. White cerebellum sign. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 5 05 47 Condition Image ----- Active space ----- 6. Moya-moya disease : More common in children. Clinical feature : H/o multiple episodes of fainting, stroke. MRI brain + Angiography : Puff-of smoke ap- pearance (Narrowed ICA → Large tuft of basal collateral arteries). CT in Head trauma 00:17:35 Head trauma CT interpretation protocol : Bleed on CT Intra-axial (Edema) Extra-axial (cortical shift, no edema) Hemorrhagic contusion Shape of bleed EDH SDH SAH Acute Rt Extra dural hemorrhage Subdural hemorrhage Subarachnoid Source : MMA. Source : Bridging cortical veins. hemorrhage Bleeding stages of SDH on CT : Acute SDH (Hyperdense) Subacute SDH (Isodense) Chronic SDH (Hypodense) IOC : MRI Radiology Revision v1.0 Marrow 6.5 2023  48 05 Radiology ----- Active space ----- Diffuse axonal injury : H/o head trauma (E.g. RTA). Non-improving altered sensorium. Normal early CT brain. Pathology : Head trauma → Twisting force on neuron → Break at the junction of cell body and neurofilament of neurons diffusely → Petechial hemorrhages develop. MRI : GRE (Gradient echo)/SWI(Susceptibility weighted imaging) → Blooming (Black spots) at grey-white matter junction/corpus callosum/brain stem. Diffuse axonal injury Tension pneumocephalus : Fracture involving skull base of anterior cranial fossa (Involves PNS) → Air enters into intracranial space → Compress brain. Tension pneumocephalus (Mount fuji sign) Brain tumours 00:23:26 Acoustic/vestibular schwannoma : Mass at cerebello-pontine angle. On CT : Ice cream on cone appearance. If present B/L : Neurofibromatosis type 11. Acoustic/vestibular schwannoma Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 5 05 49 Pituitary adenoma : ----- Active space ----- Tumor in sella and supra-sellar area. On CT : Snowman/figure of 8 appearance. Types : Pituitary macroadenoma : (> 10 mm). Craniopharyngioma : Suprasellar mass lesion. Cystic-solid lesion. Calcification +ve. More common in children. Tuberous sclerosis : Subependymal nodules Subependymal giant cell astrocytoma Ependymoma vs Medulloblastoma : Ependymoma : Medulloblastoma : Lesion from floor of 4th ventricle. Lesion from roof of 4th ventricle. Radiology Revision v1.0 Marrow 6.5 2023  50 05 Radiology ----- Active space ----- Meningioma : Broad base Prototype extra-axial lesion. Dura tail towards dura. M/C primary non- glial tumor. Dural tails : Pathognomonic. Association : MISME syndrome (NF type 11). Multiple Inherited Schwannoma, Dura tail Meningioma, Ependymoma. Meningioma Corpus callosum lipoma Oligodendroglioma Hypodense lesion with bracket shaped calcification. Cortical calcified tumor in middle age. Intra-axial tumors : Children Adults Overall M/C Astrocytoma Metastasis > Glioma 2nd M/C Medulloblastoma - 3rd M/C Ependymoma - Glioblastoma multiforme (GBM) : WHO grade IV tumor. Aggressive : Spreads across corpus callosum to other side→ Butterfly glioma. On CT : Thick irregular rim of peripheral enhancement & central necrotic area. Juvenile nasopharyngeal angiofibroma (JNAF) : Epistaxis in adolescent young males. On CT : Mass centered at sphenopalatine foramen. On MRI : Salt and pepper appearance. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 5 05 51 ----- Active space ----- Syndromic association of tumors : Syndrome Tumors NF type 1 Optic glioma, plexiform NF & brainstem glioma. NF type 11 MISME syndrome HIPPLE : Hemangioblastoma of cerebellum. Increased risk of RCC. Pheocromocytoma. Pancreatic cysts/cancer. Epididymal pappilary cystadenoma. Liver cysts. vHL Cerebellar hemangioblastoma RCC Infections of brain & Multiple sclerosis 00:32:12 Ring enhancing lesions : Tuberculoma. GBM. NCC (Neurocysticercosis). Metastasis. Abscess. Radiation necrosis. Toxoplasmosis. Tubercular meningitis : Classical findings : 1. Basal enhancing exudates. 2. Hydrocephalus. 3. Tuberculoma. 4. Vasculitic basal ganglia infarcts. Radiology Revision v1.0 Marrow 6.5 2023  52 05 Radiology ----- Active space ----- Basal exudates Disc and ring enhancing lesions Neurocysticercosis : Clinical features : Seizure and headache, no fever. CECT : Cyst with a dot sign. Escobar staging : Ventricular → Colloid vesicular → Granular nodular → Nodular calcified. Brain abscess : More common in young males. In K/C/O unsafe CSOM. Clinical features : Fever and altered sensorium. CT : Ring enhancing lesion in temporal lobe. Multiple sclerosis : More common in young females. Clinical features : Multiple neuro-deficits, cranial nerve palsies, remitting and recurring symptoms. MRI- FLAIR : Dawson’s fingers (Demyelinating plaques along white matter tracts). MRI- FLAIR (Dawson’s fingers) Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 5 05 53 Imaging in Chronic alcoholics 00:37:22 ----- Active space ----- Wernicke encephalopathy/wernicke korsakoff syndrome : H/O : Acute confusion, ataxia, ophthalmoplegia. Imaging : Hyperintensity/involvement of mammillary body. Marchiafava bignami disease : Non specific clinical findings : Motor/cognitive disturbances, seizures, apraxia. On imaging : Hyperintense lesion in corpus callosum (Splenium). Central pontine myelinolysis : Rapid correction of hyponatremia → Transiently improves, then deteriorates. Imaging : Hyperintensity in central fibers of pons. Radiology Revision v1.0 Marrow 6.5 2023  54 06 Radiology ----- Active space ----- RADIOLOGY REVISION 6 GIT system 00:00:37 Pneumoperitoneum : X-ray : Air under the diaphragm. Best : CXR erect. M/C done : Abdominal X-ray erect. M/C cause in adults : Perforation of bowel. Air under both diaphragm CXR erect Abdominal X-ray erect Pneumoperitoneum Signs on X-ray : Cupola sign Football sign : Large central oval Falciform ligament sign lucency in the supine position d/t Rigler’s double rising of air. wall sign Cupola sign : Free air lining the under surface of the central Doge cap sign tendon of diaphragm. Liver/GB edge sign Falciform ligament sign : Free air lining both falciform ligaments creating a sharp margin. Liver/gallbladder (GB) edge sign : Visibility of sharp margins of liver/GB d/t air lining it. Rigler’s double wall sign : Visibility of both mucosal & serosal surface of the bowel. Doge’s cap sign : Triangular hat-like appearance of air trapped within the Morrison’s pouch. CT scan showing pneumoperitoneum Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 6 06 55 Bowel obstruction : ----- Active space ----- Small bowel vs large bowel obstruction : Variable Small bowel. Large bowel. Diameter of dilated >3 cm. >5 to 6 cm. loops (3-6-9 rule). Caecum : >9 cm. Location of bowel Central. Periphery. loops. Number of loops. Multiple. Few, but massive. Air fluid levels. Multiple & short. Few & long. Gas in the large No gas. Large bowel dilated bowel. proximal to the obstruction. Bowel wall Valvulae conniventes : Haustrations : markings. Complete transverse muco- Transverse incomplete sal folds extending across the folds. lumen of the small bowel. Signs in intestinal obstruction : Step ladder appearance. Small bowel feces sign : Fecal matter in small bowel d/t excessive stasis. Radiology Revision v1.0 Marrow 6.5 2023  56 06 Radiology ----- Active space ----- String of beads sign : Transition point on CT : Most reliable CT criteria. The Air trapped in valvulae conniventes. bowel is dilated proximal to the transition point and collapsed distal to the transition point. Also gives an idea about the etiology of obstruction. Duodenal atresia : Presentation : Bilious vomiting at birth. Xray : Double bubble sign. Infantile hypertrophic pyloric stenosis (IHPS) : Presentation : Non-bilious vomiting at 6 weeks of age. Double bubble sign IOC : USG (Pylorus thickness > 4mm & length > 16mm is diagnostic). Signs in barium meal study : Caterpillar sign : D/t vigorous contraction of the stomach to push the contents. Mushroom sign String sign Shoulder sign : Shouldering like narrowing into the pylorus. String sign : Narrowed pylorus appears like a Barium meal showing IHPS string. Double wall sign : 2 layers of narrowed pylorus are seen. Mushroom sign : Mushroom-like duodenum (D1). Sigmoid & cecal volvulus : Presentation : Abdominal distension & absolute constipation. Sigmoid volvulus Risk factors : Elderly female, K/C/O psychiatric illness. Sigmoid volvulus (MC volvulus) Cecal volvulus X-ray : 2 loops of massively dilated large bowel 1 loop (d/t bending of the bowel)(Coffee bean sign). Haustrations lost. Haustrations +. Dilated small bowel not seen. Seen. Radiology Revision v1.0 Marrow 6.5 2023  Radiology Revision 6 06 57 Congenital diaphragmatic hernia (CDH) : ----- Active space ----- Presentation : Newborn with respiratory distress. M/C cause of death : Pulmonary hypoplasia. X-ray : Bowel loops in the thoracic cavity → Mediastinal shift towards opposite side. CDH Acute appendicitis : Presentation : Right lower abdominal pain with fever, vomiting, & tenderness at McBurney’s point. USG findings CECT findings IOC in children. IOC in adults. Blind-ended tubular edematous structure Dilated appendix with in RIF with echogenic inflamed mesentery. periappendiceal inflammatory Appendicolith ±. changes. Focussed assessment with sonography in trauma (FAST) 00:13:07 FAST protocol : 1. Subxiphoid view : 1st view. 2. Longitudinal right upper quadrant : Morrison pouch visualization (most dependent part of peritoneal cavity) → Best view. 3. Longitudinal left upper quadrant. 4. Suprapubic view. Extended-FAST (E-FAST) : Extend the assessment to the thoracic cavity. Posterior dependent part of the thorax → Look for hemothorax. Anterior non-dependent part of the thorax → Look for pneumothorax. Radiology Revision v1.0 Marrow 6.5 2023  58 06 Radiology ----- Active space ----- Mx protocol : H/o trauma. 1st step : FAST- free fluid +ve. Suggests hemoperitoneum d/t solid organ injury. Patient stable. Patient unstable. CECT : Modality of choice for Operative Mx. solid organ injury. Barium spotters 00:15:55 Esophagus : 1. Esophageal web : Seen in Plummer Vinson syndrome (Paterson Brown Kelly syndrome) : Esophageal web + dysphagia + iron deficiency anemia + hypopharyngeal squamous cell carcinoma. Esophageal web 2. Zenker’s diverticulum (M/C esophageal diverticulum) : Diverticulum is directed posteriorly. M/C complication : Aspiration. 3. Killian-Jamieson diverticulum : Diverticulum is directed anteriorly. 4. Achalasia cardia : Bird beak sign (Smooth elongated Zenker’s diverticulum tapering like a bird’s peak at the lower esophageal sphincter). 5. Ca esophagus : Rat tail appearance (Abrupt narrowing of the esophagus with mucosal irregularity). (Smooth rat tail in achalasia, Irregular rat tail in Ca Killian-Jamieson esophagus). diverticulum 6. Diffuse esophageal spasm : Corkscrew esophagus/rosary