Intra- and interoperator variability of lobar pulmonary volumes and emphysema scores in patients with chronic obstructive pulmonary disease and emphysema: Comparison of manual and semi-automated segmentation techniques

PURPOSE We aimed to compare the intra- and interoperator variability of lobar volumetry and emphysema scores obtained by semi-automated and manual segmentation techniques in lung emphysema patients. MATERIALS AND METHODS In two sessions held three months apart, two operators performed lobar volumetry of unenhanced chest computed tomography examinations of 47 consecutive patients with chronic obstructive pulmonary disease and lung emphysema. Both operators used the manual and semi-automated segmentation techniques. The intra- and interoperator variability of the volumes and emphysema scores obtained by semi-automated segmentation was compared with the variability obtained by manual segmentation of the five pulmonary lobes. RESULTS The intra- and interoperator variability of the lobar volumes decreased when using semi-automated lobe segmentation (coefficients of repeatability for the first operator: right upper lobe, 147 vs. 96.3; right middle lobe, 137.7 vs. 73.4; right lower lobe, 89.2 vs. 42.4; left upper lobe, 262.2 vs. 54.8; and left lower lobe, 260.5 vs. 56.5; coefficients of repeatability for the second operator: right upper lobe, 61.4 vs. 48.1; right middle lobe, 56 vs. 46.4; right lower lobe, 26.9 vs. 16.7; left upper lobe, 61.4 vs. 27; and left lower lobe, 63.6 vs. 27.5; coefficients of reproducibility in the interoperator analysis: right upper lobe, 191.3 vs. 102.9; right middle lobe, 219.8 vs. 126.5; right lower lobe, 122.6 vs. 90.1; left upper lobe, 166.9 vs. 68.7; and left lower lobe, 168.7 vs. 71.6). The coefficients of repeatability and reproducibility of emphysema scores also decreased when using semi-automated segmentation and had ranges that varied depending on the target lobe and selected threshold of emphysema. CONCLUSION Semi-automated segmentation reduces the intra- and interoperator variability of lobar volumetry and provides a more objective tool than manual technique for quantifying lung volumes and severity of emphysema

Improvement in the reproducibility of MDCT quantification of lobar pulmonary volumes using an automatic segmentation technique

Purpose: Density-based MDCT quantification (q-MDCT) of lung volumes is relevant in patients with emphysema or lung cancer. The inter- and intra-operator variabilities of q-MDCT obtained by two segmentation techniques were compared. Methods and Materials: Forty-seven chest MDCT examinations of patients with emphysema (men/women = 34/13, age range: 48-85) were selected from our database. All patients had been studied with lung function tests and a standardized imaging protocol on a 16-MDCT scanner (thickness/interval=1.25 mm; pitch=1.5). The MDCT datasets were analyzed independently by two operators using a manual procedure for delimitation of pulmonary lobes (A), and a full-automatic approach that allowed for manual refinement of lobar separation (B). Lung (V) and emphysema volumes (VE) were obtained from both lungs and each lobe. The inter- and intra-operator differences were expressed as percentages over means. Mean differences (Δ-tot) and standard deviations (SD-tot) calculated from the two approaches were compared. Results: The analysis conducted for both lungs showed minimal variability using A and no variability using B. From the lobar analysis, inter- and intra-operator variability ranges (min/max) obtained from B were lower than those from A: for V (B vs. A: Δinter-tot ± SDΔinter-tot = -3.7/1.6 ± 4/17% vs. -3.9/3.5 ± 4.5/22.6%;Δintra-tot ± SDΔintra-tot = 0.6/0.4 ± 1.3/8.1% vs. -1.5/0.9 ± 2.5/10.6%); for VE (B vs. A: Δinter-tot ± SDΔinter-tot = -3/2.9 ± 5/18.9% vs. -3/2.9 ± 8.5/23.3%; Δintratot± SDΔintra-tot = -0.5/0. ± 3.2/9.8% vs. -1.1/1 ± 5.6/13.7%). Conclusion: The reproducibility of q-MDCT lobar volumetry is improved by using an automatic segmentation technique

Three-dimensional rotational angiography for craniotomy planning and postintervention evaluation of intracranial aneurysms

PURPOSE: The authors evaluated the usefulness of three-dimensional rotational angiography (3DRA) in surgical planning and postoperative evaluation of cerebral aneurysms. MATERIALS AND METHODS: A total of 111 consecutive aneurysms in 100 patients (32 emergency referrals due to haemorrhage) were evaluated with 3DRA over a period of 3 years. The rotational study was always performed with a single injection of 20 cc of contrast agent in the afferent vessel after diagnostic cerebral angiography in the two orthogonal projections. Three-dimensional reconstructions were obtained for the pre- and postoperative assessment. RESULTS: Three-dimensional RA provides a virtual view of the surgical field with the same orientation required for the surgical approach and, compared with surgical findings, reliably defined location, orientation, morphology and relationship with parent vessels of the aneurysm in all cases. Postoperatively, it allowed better assessment of any residual lesion and of the relationship between surgical clips and parent vessels, compared with standard 2D angiography. CONCLUSIONS: 3DRA is a reliable method for preliminary assessment of cerebral aneurysms undergoing surgery. It provides multiple projections with a preview of the surgical field and study of lesion characteristics, which can help achieve faster and safer surgery. Compared with 2D angiography, the 3D model, with its multiple views, allows better assessment of postoperative outcomes. The method also significantly reduces the number of angiographic projections and therefore radiation and contrast-medium dose to the patient