Computed tomography measurement of lung volume in preoperative assessment for living donor lung transplantation: Volume calculation using 3D surface rendering in the determination of size compatibility

Abstract

The objective of this study was to describe the use of CT volume quantification assessment of candidates for LLDLT. Six pediatric candidates for LDLLT and their donors were investigated with helical chest CT, as part of the preoperative assessment. The CT images were analyzed as per routine and additional post-processing with CT volume quantification (CT densitovolumetry) was performed to assess volume matching between the lower lobes of the donors and respective lungs of the receptors. CT images were segmented by density and region of interest, using post-processing software. Size matching was also assessed using the FVC formula. Compatible volumes were found in three cases. The other three cases were considered incompatible. All three recipients with compatible sizes survived the procedure and are alive and well. One patient with incompatible size was submitted to the procedure and died because of complications attributed to the incompatible volumes. One patient with incompatible size has subsequently grown and new measurements are to be taken to check the current volumes. Different donors are being sought for the remaining patient whose lung volumes were considered too big for the prospective transplant donor lobes. Under FVC formula criteria, all cases were considered compatible. CT volume quantification is an easy to perform, non-invasive technique that uses CT images for the preassessment of candidates for LDLLT, to compare the volume of the lower lobes from the donors with volume of each lung in the prospective recipients. Size matching based on CT densitovolumetry and FVC may differ.

Comparison of pulmonary function test and computed tomography volumetry in living lung donors

“…2,4 To date, we have used FVC calculated by the number of segments in a graft lung for size matching in LDLLT, which is called "Date's formula". 9 Although our results after LDLLT have been acceptable, 2,15 our primary focus was to confirm how accurate it is to expect donor graft FVC by the number of segments in LDLLT.…”

“…9 Given that the right lower lobe consists of 5 segments, the left lower lobe of 4, and the whole lung of 19, we estimated the graft FVC using the following equation: graft FVC ϭ measured FVC of the right donor ϫ 5/19 ϩ measured FVC of the left donor ϫ 4/19. When the graft FVC was larger than 50% of predicted FVC of the recipient (calculated according to height, age, and sex), we accepted the size disparity regardless of the recipient's diagnosis.…”

“…5,6,9 Briefly, CT images were obtained during a single respiratory pause at the end of maximum inspiratory effort using a multidetector Aquilion 64 CT scanner (Toshiba Medical Systems, Tochigi, Japan). Whole lung scans were performed at a peak tube voltage of 120 kVp, with variable mAs setting using an automatic exposure control system (standard deviation, 8.5).…”

The effects of dynamic hyperinflation on CT emphysema measurements in patients with COPD

“…QCT can provide physiological information, especially when examinations (e.g., inspiratory and expiratory scans) are performed before and after maneuvers that alter patients' physiological status [14], such as MPT to induce DH. Other QCT techniques for the quantification of lung volumes have also proven useful for assessing other cohorts of patients, such as those with obliterative bronchiolitis and candidates for living-donor lung transplantation [25,26]. QCT has also been demonstrated to be an objective method of assessment and outcome prediction in patients with COPD who are candidates for lung volume reduction surgery or endobronchial valve implantation [18,27].…”

Diagnóstico tomográfico de enfisema pulmonar

“…Among the most common indications are cases of patients with recurrent spontaneous pneumothorax, patients with severe emphysema, candidates for invasive procedures (such as lung volume reduction surgery) or minimally invasive procedures (such as the placement of intrabronchial valves or stents) for emphysema treatment, patients with alpha-1 antitrypsin deficiency and candidates for lung transplantation. (10) However, CT densitometry and volumetric assessment can also be performed on chest X-rays requested for different reasons, such as to evaluate lung cancer or cystic lung diseases. Provided that a certain degree of variability (due to the various slice thicknesses or to the use of intravenous contrast, among others) is accepted,…”