Radiology

Chest

PA

Who, What, Why?
Prior imaging	oldest & most recent
Technical quality	Rotation (spinous processes equidistant from medial end of clavicles) Inspiration (6 - 7 anterior ribs in MCL) Penetration (spinous processes visible)
Lines, tubes	ETT: 5 cm sup to carina [just sup to arch] [has excursion +/- 2 cm] Trachoeostomy tube tip: 1/2 to 2/3 from stoma to carina CVC: SVC (if RA → may arryth or perforatn) S-G: < 2 cm lat to hila NGT: > 10 cm w/n stomach FT: lig of Trietz Neonate: ETT 1 - 1.5 cm sup to carina UAC: b/n celiac axis & arch or inf to renal arts (L3-L5) UVC: IVC
Abdomen	Diaphragm, pneumoperitoneum, colonic interposition, costophrenic angles, subpulmonic effusion (highest point of hemidiaphragm displaced laterally), tension pneumothorax
Thoracic cage	#'s, lesions, notching, pneumothorax
Mediatinum	Heart (size, contour), great vessels, airways, esophagus, LN's, AP window, paratracheal stripe, paraspinal lines, ant & post junction lines, azygoesoph recess
Lung parenchyma	CPA, apices, volumes, vascular markings, lesions (including behind heart & diaphragm), pneumothorax

Lateral: diaphragm, CPA, spine sign, hilar LAD, posterior wall of bronchus intermedius, upper lobe bronchi, retrosternal space



Opacity

Etiologies: Blood, pus, fluid, cells, protein

Common findings in ICU: edema, atelectasis, effusion, cardiomegaly, life supports

Cardiogenic pulmonary edema progession:
® vascular redistribution
® interstitial pulmonary edema (perihilar haze, peribronch cuffing, Kerley A & B lines)
® alveolar pulmonary edema
® pleural effusion

Air-space disease	Fluffy margins Acinar shadows (7 mm) Air bronchograms Silhouette sign Homogeneous (when acinar consolidation confluent) Non-segmental distribution (d.t. intersegmental channels)
Interstitial disease	Ground-glass (granular) Reticular (fine, medium, coarse; Kerley A, B, C lines; acute: hazy, not distorted; chronic: sharp, distorted) Nodular Reticulonodular Honeycomb (5 - 10 mm)
Atelectasis	Volume loss, no air bronchograms if resorption atelectasis Resorption (e.g. d.t. mucus plug) Relaxation (passive) Adhesive (e.g. d.t. abnl surfactant) Cicatrization (d.t. pulmonary fibrosis)
Benign Nodule	Size: <2 cm Margins: well-defined, smooth Calcification: laminated, multiple punctate, or popcorn Fat indicates hamartoma Growth: none over 2 yrs Age: below 40 y/o

Pleural Effusion

Can see 25 mL on lat decub
Can see 300 mL on PA


Mediastinal Masses

Anterior	Thyroid Thymoma Teratoma Terrible lymphoma
Middle	Lymphadenopathy Esophageal mass Hernia, Hematoma Aneurym Bronchogenic cyst Inflammation (sacoidosis, T.B., histoplasmosis, coccidioidomycosis) Tumor
Posterior	Aneurysm Neurogenic tumor Spine mass

Aortic Disruption

left Bronchus depressed
left pleural Effusion
widened Mediastinum
apical Cap
Aortic knob indistinct
Trachea deviated to right

Asbestos-related pleural disease: pleural plaques, diffuse pleural thickening, pleural calcification, benign effusion
Pleural calcification without h/o surgery, TB, empyema, hemothorax, etc. is pathognomonic of asbestos exposure.

Asbestosis is asbestos-related interstitial pulmonary fibrosis

	answer Normal
answer Normal	answer Normal

Consolidation
• Lobar or segmental density
  
• Air bronchogram - presence of air bronchogram confirms an alveolar process
  
• Insignificant loss of lung volume

  answer Lingular consolidation	answer Left lower lobe consolidation
  answer Right upper lobe consolidation	answer Right middle lobe consolidation
  answer Focal areas of consolidation in LLL & R suprahilar area SARS

Atelectasis

• A density - representing lung devoid of air
  
• Loss of lung volume

  answer Left lower lobe atelectasis	answer Left upper lobe atelectasis
  answer Right lung atelectasis	answer Right upper lobe atelectasis - with Golden's S-sign
  answer Right lower lobe atelectasis
  answer Right middle lobe atelectasis	answer Right upper lobe atelectasis
  answer Anterior subsegmental atelectasis of RUL	answer subsegmental atelectasis

Miscellaneous

answer Adult respiratory distress syndrome (non-cardiogenic pulmonary edema) distinguishing characteristics: - normal size heart - no pleural effusion	answer Solitary pulmonary nodule
answer Left cervical rib	answer Emphysema - hyperlucent lung fields - multiple blebs - avascular zones - prominent pulmonary arteries - increased radiologic TLC - increased retrosternal & infracardiac air space
answer Silicosis - miliary nodules - L subpulmonic effusion	answer Sarcoidosis - miliary nodules - hilar lymphadenopathy
answer Achalasia	answer Dissecting aneurysm
answer Hiatal hernia	answer Honeycombing
answer Miliary tuberculosis	answer Pleural fibrosis
answer Pulmonary edema	answer Hamartoma
answer Erosion of posterior ribs (due to rheumatoid arthritis)	answer Histoplasmosis
answer Pneumomediastinum	answer Pneumoperitoneum
answer Right pneumothorax	answer RUL cancer - paratracheal lymphadenopathy
answer Pulmonary infarct (Hampton's hump)	answer Anterior mediatinal mass DDx: Thymoma Teratoma Thyroid (intra thoracic goiter) Testicular Ca metastases (Terrible)lymphoma
answer Fungus ball	answer Gloved finger sign
answer Pleural & mediastinal fibrosis SVCO - collaterals with azygous & hemiazygous system Smaller right hemithorax Haziness of right hemithorax Lines not corresponding to anatomical structures (A) Prominent azygous vein/node (B) Prominent aortic nipple (C) S&S's: Puffiness of face in the early mornings for years which subsides by evening. Usually wakes up with headcahe. No swelling of legs. Extensive, prominent veins in the chest wall with direction of blood flow towards legs.	answer Reticulonodular pattern Chest film: reticulonodular pattern CT: multiple small nodules, each with ground glass halos

Consolidation
Opacification
Lobar/Segmental distribution
Air bronchogram
No significant loss of lung volume

Etiology


Streptococcus
Legionella
Mycoplasma


Post-obstructive Atelectasis

Opacity (airless lung)
Signs of loss of lung volume:
Mediastinal shift
Elevated diaphragm
Movement of fissures
Shift of hilum
Change of proportion of lungs
Smaller hemithorax
Compensatory hyperinflation

Etiology

Cancer
Foreign body
Benign tumor
Granuloma

Pneumothorax

Dark field with no vascular markings in the pleural space
Visible collapsed lung
Larger hemithorax
Etiology
All Lung Diseases
Trauma
Procedures
Barotrauma (Ventilator)
Bullous lesions
Marfan syndrome
Ehler Danlos syndrome
Catamenial Pneumothorax

Lung Mass

Homogenous liquid density
Density >5 cm diameter (less than 5 cm is called pulmonary nodule)
Sharp margins
No respect for segments or fissures
Etiology
Lung cancer
Granulomatous infections (TB, Histo,Blastomycosis)
Wegners Granuloma
Rheumatoid lung
Metastasis

Pleural effusion

Loss of costophrenic angle
Loss of diaphragmatic shadow
Homogenous opacification
Shift of mediastinum to opposite side
Ellis line
Etiology (common diseases)
Congestive heart failure
Cancer
Tuberculosis
Empyema
Hemothorax


Cavity

Etiology
Lung cancer: Squamous cell cancer Lung (Thick wall, Irregular lumen, Stalactites and Stalagmites)
Metastasis
Wegners Granuloma
Rheumatoid lung
Cystic fibrosis
Granulomatous infections TB, Histo
Lung abscess
Necrotizing Pneumonia
Coccidiomycosis
Fungous ball (Mobile ball inside a cavity)


Congested lungs In CHF, there is progression from

Vascular congestion (recognized as prominent pulmonary veins)
cephalisation.
Next, interstitial edema and increased lymph flow manifests itself as Kerley lines.
Next, basal congestion with smaller lungs due to increased elastic recoil. Congested, boggy Liver also pushes the diaphragm up.
Lastly, full-blown pulmonary edema: acute diffuse alveolar pattern

Chest wall lesion

Peripheral density
Sharp inner margin
Indistinct outer margin
"Cat under the rug" appearance with shallow concave edges.
Etiology
Expanding rib lesions
Fracture with hematoma
Callus
Metastasis
Plasmacytoma
Parietal pleural masses (mesothelioma)
Neurofibroma
Plumbage

Solitary pulmonary nodule

Liquid density
Distinct margin
Between 2-5 cm diameter
Oval or round
no other lesions
Etiology
Cancer
Benign tumor
Granulomas
Rare but characteristic conditions:
AVM
Rheumatoid nodule
Round atelectasis
Hydatid cyst

Lymphadenopathy

Polycyclic margin
Clear space between heart and the nodal density with hilar nodes
Extrapleural sign with mediastinal nodes
Widening of mediastinum
Etiology
Cancer Lung
Lymphoma
Granulomatous diseases
TB
Sarcoidosis
Histoplasmosis
Silicosis


Diffuse lung disease
categorized into

Alveolar
Interstitial
Vascular
Most of the time, mixed and difficult to categorize into one pattern.

Diffuse interstitial pattern

Lines (Kerley lines)
Nodules
Honeycombing


Common etiology

Granulomatous disease
Miliary TB
Sarcoidosis
Silicosis
Lymphangitic spread
Idiopathic fibrosis
Drug induced fibrosis


Diffuse alveolar pattern

Butterfly or medullary distribution
Lobar or segmental densities
Soft fluffy coalescing densities
Air bronchogram
Alveologram
Common causes
Acute:
Water
Blood
Inflammatory exudate

Chronic:
Alveolar proteinosis
Alveolar form of Lymphoma
Alveolar form of Sarcoidosis
Alveolar form of TB
Fungal infections
Mineral oil aspiration
Desquamative interstitial pneumonia

Mediastinal mass

Homogeneous liquid density
Distinct margin
Mediastinal because has Extrapleural sign (peripheral, absence of one of the margins both in PA and lateral view)
Location is suggested by x-rays to be anterior mediastinum

Common Mediastinal masses in the anterior mediastinum

Thymoma
Teratoma
Thyroid
Testicular metastasis
Terrible lymphoma


Mediastinal Lymphadenopathy

Widening of Mediastinum Polycyclic margin indicating that they are multiple nodes
Widening of Carina with subcarinal nodes

Etiology

Lymphoma
Cancer Lung
Granulomatous diseases
Castleman's disease

Lesions of apices of Lungs

Common diseases:
Tuberculosis
Pancoast tumor
Components of Pancoast tumor
Apical shadow
Destruction of posterior 1st and second rib
Horner's syndrome
Brachial plexus involvement
In the CXR you cannot recognize Horner's and brachial plexus involvement (sometimes shoulder sags on that side).
You should always take a very close look at ribs for destruction. If it is present most likely it is cancer.

Multiple diffuse nodules

Granulomatous diseases: Miliary TB
Sarcoidosis
Histoplasmosis
Silicosis
Eosinophilic granuloma
Metastasis from Thyroid
Alveolar cell carcinoma

Multiple mass lesions
Whenever you see multiple mass lesions considerations are either the disease process is at the end of vessel or bronchus, as both of them branch and reach lung tissue.

Vascular:
Tumor emboli/Metastasis
Septic emboli
Vasculitis/Wegners granuloma

Bronchial:
Aspiration
Tumor emboli are in the interstitum and there is no inflammation, hence the margins of the mass lesions are sharp.

Lung abscess
Any time you see a fluid level in a cavity, the most likely diagnosis is Lung abscess. I am not even going to give you other uncommon causes.

Common segments where aspiration lung abscess occurs:

Axillary subbasement of anterior and posterior RUL segments
Superior segment of RLL
Superior segment of LLL
These three segments will account for 85-90% of all aspirated lung abscesses. This is determined by patients position at the time of aspiration. Gravity determines which segment the aspirate will end up in.

Etiology for Lung abscess:
Endobronchial lesion
Deglutition problem
Esophageal disease

Diffuse alveolar infiltrates Soft fluffy lesions
Coalescing lesions
Air bronchogram
Butterfly/Medullary distribution
Cortical distribution
Alveologram
Segmental/Lobar density
Etiolgy of Chronic alveolar infiltrates. Alveolar proteinosis
Alveolar form of Sarcoidosis
Alveolar form of TB
Alveolar form of Lymphoma
Psudolymphoma
Alveolar cell carcinoma
Mineral oil aspiration
Alveolar pattern of metastases

Bullous Emphysema
Look for avascular regions, hyperlucent areas.
Lines that do not correspond to known fissures could be walls of blebs.
Bullae become evident when there is Pneumothorax, look carefully along the pleural surface of atelectatic lung.

Etiology

In routine Emphysema
Bullous emphysema (No airway obstruction)

Loculated Empyema

Homogenous density
Often mistaken for consolidation or Pleural effusion
Criteria for lobar consolidation or Pleural effusion not met
Lines not corresponding to fissures
Lateral view most helpful


Inlet to outlet sign:
Structures traversing from inlet to outlet of Thorax

Aorta on left
Esophagus on right

Inlet to outlet shadow
Widening of mediastinum
Inhomogeneity of cardiac density
Etiolgy

Dissecting Aneurysm of Aorta (The wavy margins is suggestive of dissection of Aorta)
Right sided Aortic arch
Achalasia of Esophagus

Abdominal

Prior imaging	oldest & most recent
Lines, tubes	E.g. NGT, Dubhoff feeding tube
Stones	Nephrolithiasis, cholelithiasis
Bones	Ilioishial line, iliopectineal line, arcuate lines, Shenton's arc, coxa vara or valgus, protrusio acetabuli, anterior & posterior rim lines, femoral head, bone texture, joints
Mass
Gas	Obstruction, ileus

answer Appendicitis Dilated appendix with marked wall edema and peripheral rim enhancement	answer Pancreatic lipomatosis Common condition in which the exocrine tissue is partially or completely replaced by fat.
	Arterial phase & portal venous phase
answer multiple gallstones	answer Hepatic hemangiomas Contrast-enhanced CT: characterized by hypodense center with enhancement of periphery. Enhancement progresses centripetally.
answer Xanthogranulomatous pyelonephritis (XGP)R kidney Nearly all cases secondary to obstructive uropathy Ultrasound findings: lack of corticomedullary differentiation; staghorn calculi. CT findings: enlarged, non-functioning kidney; multiple, non-enhancing xanthomatous masses (-10 to –30 HU); large staghorn calculus; thickened Gerota’s fascia.	answer Adenomyosis Enlarged uterus with diffuse thickening & poor definition of the junctional zone. Small T2 hyperintensities noted within thickened junctional zone compatible with cystic degeneration. 3 small fibroids noted.
answer DDx: cholangitis, choledochal cyst Caroli disease/Caroli syndrome. Fatty liver with slight nodular contour, consistent with cirrhotic changes. Multifocal segmental saccular dilatation of intrahepatic bile ducts, especially in segment 5 of posterior right lobe. Several round hypodense cystic structures containing air-fluid levels, which communicate with intrahepatic bile ducts. Pneumobilia (d.t. recent sphincterotomy). Mild splenomegaly.
answer Rectus sheath hematoma	answer Cecal volvulus

Musculoskeletal

Stability = Propensity to further displacement

Fractures

Prior imaging	oldest & most recent
Location	E.g. proximal, middle, distal third
Type	E.g. transverse, oblique, spiral, comminuted, green stick, torus, stress, insufficiency
Joint involvement
Displacement	E.g. 50% posterior
Angulation	E.g. vertex medial
Rotation
Over-riding / distraction
Effusions
Soft tissue swelling
Hardware	Correct positioning, lucencies, osteomyelitis, #'s E.g. intramedullary rod, dynamic hip screw, spinal fusion plate & screws, k-wires, cortical screws, cancellous screws,cerclage wire, tension band wire, external fixator Orthopedic hardware

Tooth Numbering System

C-Spine

Prior imaging	oldest & most recent
Bodies	Height, trabeculations
Disks	Height,
Odontoid	#'s, dens-anterior arch distance (adults: < 3 mm; peds: < 5 mm)
Lines	Anterior spinal line, posterior spinal line, spinolaminar line, clivus base line
Lordosis
Soft tissue swelling	Retropharyngeal, retroesophageal

Degenerative Disease of Spine

Degenerative disk disease (DDD)	↓ disk space osteophytes borders of adjac vert bodies may vacuum phen
DISH	flowing ossifn >= 4 contig verts no facet or SIJ ankylosis rel minimal DDD
Spondylosis deformans	ant & lat osteophytes rel preserved disk spaces
Facet DJD	osseous facet overgrowth ↓ jt space sclerosis

Facet DJD + DDD may → degen spondylolisthesis

Scheuermann's disease

Categorized as an "osteochondrosis"
Possibly a growth disorder of vertebral bodies (poorly understood)
Typically 13-17 y/o with back pain
Lower thoracic spine involved most frequently

Radiographs:
Multiple Schmorl's nodes
Disk space narrowing
Endplate irregularities
Anterior wedging
Changes seen in >3 vertebral bodies (with > 5 degrees anterior wedging in each)
Kyphosis usually > 35 degrees




Shoulder

A-C joint	3 - 8 mm
Coracoid - clavicular distance	10 - 13 mm
Glenoid - humeral distance	?8 mm

Acetabulum

Ileopectineal Iileopubic) line
Ileoischial line
Tear drop
Posterior rim
Superior rim
Anterior rim


Ankle Fracture

Medial malleolus
Lateral malleolus
Posterior malleolus
Base of 5th metatarsal
Dome of talus
Lateral talar process
Anterior calcaneal process
Lateral calcaneal process
Proximal fibula
Soft tissue swelling


Accessory Bones


Arthritides

Osteoarthritis "Wear & tear exceeds repair."	Subchondral sclerosis Osteophytes Asymmetric joint space narrowing Pseudocysts
Rheumatoid arthritis	Erosions Symmetric joint space narrowing Soft tissue swelling Osteopenia (periarticular)
Charcot joint	Joint destruction Heterotopic bone formation Subluxations

Bone Tumors

Margins

I - Geographic	A - well-defined & sclerotic B - well-defined & not sclerotic C - ill-defined	usually benign usually benign not ...
II - Moth-eaten
III - Permeated

Periosteal Reaction

Aggressive: sunburst, hair-on-end, Codman triangles, laminated

Osteomyelitis

Plain films (require 10-14 days to develop):

STS
Periosteal reaction
Lytic changes (Require 2-6 weeks and reflect 50-70% bone density loss. Antibiotic use may arrest bone mineral loss.)

Triple phase bone scan

Can diagnose osteomyelitis within 3 days of symptom onset. 95% sensitive and specific.
False positives: healing fractures, prostheses, neuropathic osteoarthropathy.
In this instance, Indium-labeled WBC images are superimposed on the bone scan.

Spine