Three-dimensional CT angiography of anatomic variations in the pulmonary arterial tree.

PURPOSE: Anatomic variations of the pulmonary arterial tree can cause technical difficulties during pulmonary lobectomy in general and video-assisted thoracic surgery (VATS). Using CT angiography and 3D reconstruction, we sought to identify anatomic variations of the pulmonary arterial tree and assess their respective frequencies. METHODS: We retrospectively studied 88 pulmonary arterial trees in 44 patients having undergone VATS lobectomy for lung cancer over an 18-month period in Amiens University Hospital's Department of Thoracic Surgery. Each CT angiography with 3D reconstruction of the pulmonary arterial tree was performed by two experienced operators, according to a standardized procedure. RESULTS: On the right side, the upper lobe was supplied with blood by a mediastinal artery in 100% of cases and by one or more fissural arteries in 88.6%. The middle lobe was usually supplied by two arteries (54.5%). The upper segment of the right lower lobe was usually supplied by a single artery (90.9%). We identified 11 variations in the vasculature of the basal segments. On the left side, the upper lobe was supplied by four arteries in 50% of cases, three culminal arteries (50%), and a fissural lingular artery (77.3%). The upper segment of the left lower lobe was usually supplied by a single artery (65.9%). We identified 15 anatomic variations in the vasculature of the basal segments. We observed that the origin of the apical artery of the right lower lobe was proximal to the origin of the middle lobe artery in 38.6% of cases. The origin of the apical artery of the left lower lobe artery was proximal to the origin of the lingular fissural artery in 65.9% of cases. CONCLUSION: The findings of the present CT angiography/3D reconstruction study agreed with the reference works on the anatomy of the pulmonary arterial tree and defined the frequency of anatomic variations. It is essential to assess the anatomy of the pulmonary arterial tree before VATS lobectomy.

Lymphatic drainage of lung cancer follows an intersegmental pathway within the visceral pleura.

OBJECTIVES: Lung cancer tumors are known to be highly lymphophilic. There are two different pattern of lymphatic drainage of the lung: one peribronchial lymphatic pathway, and another one within the visceral pleura which appears to be more intersegmental than the peribronchial pathway. We aimed to assess the prevalence of an intersegmental pathway in the lymphatic drainage of lung tumors within the visceral pleura and determine potential influential factors. METHODS: In this prospective study, we included all patients for whom a major pulmonary resection (lobar) was indicated and performed for suspected or proven lung cancer. An immediate ex-vivo evaluation of the surgical specimen after resection was conducted by trans-pleural injection of blue dye within the tumor. The pathways followed by the lymphatic vessels under the visceral pleura were assessed to define the occurrence of an intersegmental pathway, which was defined by the presence of blue dye within the lymphatic vessel crossing to a neighboring pulmonary segment, distinct from the tumorous segment. RESULTS: Fifty-three patients met the inclusion criteria and were assessed over a three-year period. Lymphatic drainage within the visceral pleura followed an intersegmental pathway in 35 of 53 patients (66 %). When the lymphatic drainage of the tumor was intersegmental, it drained in a single other segment in 21/35 cases and two or more in 14/35 cases. Logistic regression with multivariate analysis showed a peripheral location of the tumor to be a risk factor for the intersegmental pathway of visceral pleura lymphatic drainage (OR = 0.87 [079-0.95], p = 0.003). CONCLUSION: These results confirm that lymphatic drainage of lung cancer in the visceral pleura appears to largely follow an intersegmental pathway, especially when the tumor is peripheral, close to the visceral pleura.