High resolution computed tomography (HRCT) and new perspectives in functional radiology of the lung.

Computed Tomography (CT) with the advent of new techniques as high resolution computed tomography (HRTC) and spiral CT with 3D reconstructions (3D CT) allows a new morphologic-qualitative as well as functional-quantitative evaluation of pulmonary perfusion and ventilation. HRCT allows the identification of secondary lobule and a detailed morphologic and comparative analysis of minute distal anatomical structures with combined densitometric evaluation of lung parenchyma on perfusion. In particular, a new, more specific significance could be attributed to changes in density of lung parenchyma (mosaic pattern) with associated assessment of the vessel number, caliber and distribution, and a comparative evaluation of vessels and density between healthy and impaired areas. The "optical" HRCT evaluation on serial axial scans in inspiration and expiration allows the functional assessment of compartments which require spirometry and tests of respiratory function. Spiral CT allows volumetric acquisitions in a single breath which can be reconstructed and processed according to single requirements. 3D tailored reconstruction of spiral CT exam in maximum inspiration and expiration with a dedicated densitometric window (-1024/+ 100 HU) allows the calculation of total lung volume (TLV), of both lungs, of a single lung or selected sections. With the "air" densitometric window (-1024/-400 HU) the total lung capacity (TLC) and residual volume (RV) are calculated. The ratio between these values and the corresponding TLV represents the lung aeration index (LAI). 3D reconstruction with fixed densitometric value corresponding to median air density (peak of histogram) allows the scintigraphic-like "alveolographic" reconstruction of lung ventilation. Combined 3D CT and HRCT evaluation possibly from a single spiral CT exam, is used in the morphologic-functional diagnosis of respiratory pathophysiology.

[Lung transplantation: the physiopathological considerations and imaging diagnosis problems]. / Trapianto del polmone: considerazioni fisiopatologiche e problematiche di diagnostica per immagini.

In the last years, lung transplantation has become a widely accepted treatment for the patients suffering from end-stage chronic lung disease. This study was aimed at investigating the role of diagnostic imaging techniques before and after lung transplantation, in the light of the physiopathological changes occurring in transplanted lungs. Our study included 4 patients (3 men and 1 woman, age range: 33-58 years): 3 of them underwent single lung transplantation and one double lung transplantation. All the operations were successful. Chest radiographs and HRCT showed the main early and late complications that occurred after transplantation. In the early postoperative period, the reperfusion syndrome was observed in 2 patients and acute rejection in the 3 patients submitted to single lung transplantation. In the late postoperative period, chronic rejection occurred in the patient submitted to left lung transplantation. None of our patients presented any infection or such airway complications as bronchial dehiscence or strictures. Both literature data and our personal experience show that preoperative diagnostic imaging allows the assessment of lung conditions, which helps choose the better side for transplantation. Moreover, lung size must be studied to match the donor's lung to the recipient's chest. In the postoperative period, both early and late complications must be investigated, all of them characterized by aspecific radiologic findings. Currently, time plays a major diagnostic role but we hope that more accurate interpretation of radiologic findings will improve the clinical assessment of lung transplant recipients.