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Lung Perfusion
Jud W. Gurney, MD, FACR
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KEY FACTS

  • Terminology

    • Imaging Findings

      • Top Differential Diagnoses

        • Clinical Issues

          TERMINOLOGY

          • Definitions

            • Arterial branching pattern
              • Arteries accompany bronchi
                • Supernumerary branches common and increase toward the lung periphery
                • Supernumerary arteries branch at right angles from the parent artery (airways never have right angle branches)
            • Pulmonary artery pressure affected by gravity
              • Mean pulmonary artery pressure 15 mm Hg (~20 cm H₂O)
                • Apex lung approximately 20 cm above the left atrium, mean pressure just adequate to reach apex of lung
              • Mean pulmonary venous pressure 5 mm Hg
              • Average pulmonary blood flow 2.0 mL/min-ml tissue
            • Perfusion (Q): Gravity alterations
              • Main pulmonary artery inclined towards the left upper lung, the jet effect across the pulmonic valve increases blood flow 10% above similar regions in the right upper lobe
              • Zonal blood flow
                • Blood flow determined by pulmonary arterial (pa), pulmonary venous (pv), and intra-alveolar pressure (pA)
                • Zone 1: pA > pa > pv no blood flow through collapsed capillaries
                • Zone 2: pa > pA > pv blood flow determined by gradient between pulmonary arterial and pulmonary alveolar pressure
                • Zone 3: pa > pv > pA blood flow determined by arterial venous pressure gradient
            • Perfusion (Q): Nongravity alterations
              • Normal 4 fold increase in flow from the central to the periphery of the lung in isogravitational plane
                • Possibly related to length of arteries but less well understood than perfusion alterations due to gravity
              • Secondary pulmonary lobule: Similar gradient from the core bronchovascular structures decreasing to the periphery of the lobule
            • Hypoxic vasoconstriction: Regional regulatory mechanism to match ventilation with perfusion

          IMAGING FINDINGS

          • Radiographic Findings

            • CT Findings

              • MR Findings

                • Nuclear Medicine Findings

                  DIFFERENTIAL DIAGNOSIS

                    PATHOLOGY

                    • General Features

                      • Gross Pathologic & Surgical Features

                        CLINICAL ISSUES

                        • Presentation

                          Selected References

                          1. Vonk-Noordegraaf A et al: Noninvasive assessment and monitoring of the pulmonary circulation. Eur Respir J. 25(4):758-66, 2005
                          Related Anatomy
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                          Related Differential Diagnoses
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                          References
                          Tables

                          Tables

                          KEY FACTS

                          • Terminology

                            • Imaging Findings

                              • Top Differential Diagnoses

                                • Clinical Issues

                                  TERMINOLOGY

                                  • Definitions

                                    • Arterial branching pattern
                                      • Arteries accompany bronchi
                                        • Supernumerary branches common and increase toward the lung periphery
                                        • Supernumerary arteries branch at right angles from the parent artery (airways never have right angle branches)
                                    • Pulmonary artery pressure affected by gravity
                                      • Mean pulmonary artery pressure 15 mm Hg (~20 cm H₂O)
                                        • Apex lung approximately 20 cm above the left atrium, mean pressure just adequate to reach apex of lung
                                      • Mean pulmonary venous pressure 5 mm Hg
                                      • Average pulmonary blood flow 2.0 mL/min-ml tissue
                                    • Perfusion (Q): Gravity alterations
                                      • Main pulmonary artery inclined towards the left upper lung, the jet effect across the pulmonic valve increases blood flow 10% above similar regions in the right upper lobe
                                      • Zonal blood flow
                                        • Blood flow determined by pulmonary arterial (pa), pulmonary venous (pv), and intra-alveolar pressure (pA)
                                        • Zone 1: pA > pa > pv no blood flow through collapsed capillaries
                                        • Zone 2: pa > pA > pv blood flow determined by gradient between pulmonary arterial and pulmonary alveolar pressure
                                        • Zone 3: pa > pv > pA blood flow determined by arterial venous pressure gradient
                                    • Perfusion (Q): Nongravity alterations
                                      • Normal 4 fold increase in flow from the central to the periphery of the lung in isogravitational plane
                                        • Possibly related to length of arteries but less well understood than perfusion alterations due to gravity
                                      • Secondary pulmonary lobule: Similar gradient from the core bronchovascular structures decreasing to the periphery of the lobule
                                    • Hypoxic vasoconstriction: Regional regulatory mechanism to match ventilation with perfusion

                                  IMAGING FINDINGS

                                  • Radiographic Findings

                                    • CT Findings

                                      • MR Findings

                                        • Nuclear Medicine Findings

                                          DIFFERENTIAL DIAGNOSIS

                                            PATHOLOGY

                                            • General Features

                                              • Gross Pathologic & Surgical Features

                                                CLINICAL ISSUES

                                                • Presentation

                                                  Selected References

                                                  1. Vonk-Noordegraaf A et al: Noninvasive assessment and monitoring of the pulmonary circulation. Eur Respir J. 25(4):758-66, 2005