α physiologic correlation - medinfo2.psu.ac.thmedinfo2.psu.ac.th/pr/chest2012/chest2010/pdf/[12]...

Physiologic correlation

• Boyle's Law P.V = K • Hooke's Law ΔL α ΔT • Laplace's Law ΔP = 2.T/r• Poiseuille's Law R = 8.L.eta/(pi.r4)• The Fanning Equation ΔP α 1/r5

• Fick's Law Vgas α A*ΔP/L• Graham's Law D α sol / MW0.5

• Charles' Law V = K'. T

a

b

cd

d

MorphologyPhysiology

Physiology of lung

1. Perfusion, Q2. Ventilation, V3. Lymph flow, L4. Stress or Strain, S

Relate with gravity.Upper and lower portions are different.

• Vertical physiology• Axial physiology• Physiology of the secondary pulmonary

lobule

Cross-sectional imagingVertical physiology

Vertical Physiology

• Upper lobe predominant:Tbc, Silicosis and Sarcoidosis

(Less lymph flow)

• Lower lobe predominantMetastases, Pulmonary edema

(More perfusion)

Axial physiology

Axial physiology• Pulmonary Cortex vs Medulla

Axial Streaming

100 micron7.5‐80 micron

Silicone injection Bat’s wing

Perfusion• Lung Metastases

Cortex and lower

Perfusion

• Poisoning (Bleomycin), Immune complex in Scleroderma or Rheumatoid

Cortex, Lower, Posterior

Scleroderma

Ventilation• Particle size < 5 micron : Terminal

bronchiole, Alveolar space • Particle size < 1 micron :

Respiratory bronchiole, Alveolar sac

Ventilation

• Large particles : - Restore and excrete by Cilia- Half life : 20 minutes- Affect bronchus

• Small particles : - No cilia in the cortex- Eliminate by Macrophage - Half life : weeks

• - Affect bronchiole (Smoking)

Lymphatic drain

Lymphatic drain

• Depends on gravity and chest movement

• More expansion of anterior than posterior ribs

- Good lymph flow Ventral> Dorsal

Lymphatic drain

• Extravascular fluid drainage

- Cortex > medulla - Bat’s wing sign in

pulmonary edema

Lymphatic drain

• Residual disease usually found in upper, dorsal and central

- Superior segment of lower lobe - Posterior segment of upper lobe

Stress or Stain

• Upper > Lower• Cortex > Medulla• Examples : Cavity, emphysema, bleb

and bulla in upper lobe and superior segment of the lower lobe

Emphysema in upper + peripheral parts

Secondary pulmonary lobuleSecondary pulmonary lobule

• Blood circulation : Core > Periphery (4 times)

• Transit time : Periphery > Core

Bronchopneumonia

• Lobules can be heterogeneous

-Particles finally goes to cortex.-Diseases can appear at anywhere.-Immune-activated chronic inflammation trends to remain at lower, dorsal cortex.-Residuals from immune clearance remain in upper, dorsal medulla.-Cavities trend to appear in peripheral upper.-Physiologic correlation can be better appreciated with CT.