The efficacy of 320-detector row computed tomography for the assessment of preoperative pulmonary vasculature of candidates for pulmonary segmentectomy

[Effect of Automatic Extraction Accuracy by Different Image Reconstruction Methods Using a Three-dimensional Image Analysis System for Pulmonary Segmentectomy Preoperative CT Angiography]

This study aimed to determine the optimal image reconstruction method for preoperative computed tomography (CT) angiography for pulmonary segmentectomy. This study enrolled 20 patients who underwent contrast-enhanced CT examination for pulmonary segmentectomy. The optimal image reconstruction algorithm among four different reconstruction algorithms (filtered back projection, hybrid iterative reconstruction, model- based iterative reconstruction, and deep learning reconstruction [DLR]) was investigated by assessing the CT numbers, vessel extraction ratios, and misclassification ratios. The vessel extraction ratios for main and subsegment branches reconstructed using DLR were significantly higher than those using other reconstruction algorithms (96.7% and 90.8% for pulmonary artery and vein, respectively). The misclassification ratios at the right upper lobe pulmonary vessels (V1 and V2) were especially high because they were close to the superior vena cava, and their CT numbers were similar in all four reconstructions. In conclusion, the DLR allows a high extraction rate of pulmonary blood vessels and a low misclassification rate of automatic extraction.

Chest CT Angiography for Acute Aortic Pathologic Conditions: Pearls and Pitfalls

Chest CT angiography (CTA) is essential in the diagnosis of acute aortic syndromes. Chest CTA quality can be optimized with attention to technical parameters pertaining to noncontrast imaging, timing of contrast-enhanced imaging, contrast material volume, kilovolt potential, tube-current modulation, and decisions regarding electrocardiographic-gating and ultra-fast imaging, which may affect the accurate diagnosis of acute aortic syndromes. An understanding of methods to apply to address suboptimal image quality is useful, as the accurate identification of acute aortic syndromes is essential for appropriate patient management. Acute aortic syndromes have high morbidity and mortality, particularly when involving the ascending aorta, and include classic aortic dissection, penetrating atherosclerotic ulcer, and acute intramural hematoma. An understanding of the pathogenesis and distinguishing imaging features of acute aortic syndromes and aortic rupture and some less common manifestations is helpful when interpreting imaging examinations. Related entities, such as ulcerated plaque, ulcerlike projections, and intramural blood pools, and mimics, such as vasculitis and aortic thrombus, are important to recognize; knowledge of these is important to avoid interpretive pitfalls. In addition, an awareness of postsurgical aortic changes can be useful when interpreting CTA examinations when patient history is incomplete. The authors review technical considerations when performing CTA, discuss acute aortic syndromes, and highlight diagnostic challenges encountered when interpreting aortic CTA examinations. ^©RSNA, 2021.

Thoracoscopic left S1 + 2 segmentectomy as a good resolution for preserving pulmonary function

OBJECTIVES

Segmentectomies such as S1 + 2, S1 + 2+3 and S4 + 5 segmentectomy are used to treat patients with non-small-cell lung cancer (NSCLC) in the left upper lobe. However, the preservable lung volume and changes after such segmentectomies remain unknown. We compared the residual pulmonary function after thoracoscopic segmentectomy or lobectomy in the left upper lobe and examined the efficacy of S1 + 2 segmentectomy regarding postoperative pulmonary function.

METHODS

Patients with left upper lobe NSCLC who underwent thoracoscopic segmentectomy or lobectomy were included. Spirometry and computed tomography were performed before and 6 months after resection, and the ipsilateral preserved lobe volume was calculated using 3-dimensional computer tomography. The percentage of postoperative/preoperative forced expiratory volume in 1 s and actual/predicted regional forced expiratory volume in 1 s (preservation rate) in the residual lobe were compared.

RESULTS

Eighty-eight patients underwent lobectomy and 70 patients underwent segmentectomy (23 S1 + 2, 35 S1 + 2+3 and 12 S4 + 5 segmentectomies). The percentage of postoperative/preoperative forced expiratory volume in 1 s was 97 in S1 + 2, 82 in S1 + 2+3, 86 in S4 + 5 segmentectomy and 73 in left upper lobectomy, indicating that segmentectomy could be a meaningful approach to preserve pulmonary function. The preservation rate was 83% in S1 + 2 and 62% in S1 + 2+3 segmentectomy and was significantly higher in S1 + 2 than in S1 + 2+3 segmentectomy (P < 0.001).

CONCLUSIONS

Postoperative pulmonary function and the preservable lung volume of the residual lobe after thoracoscopic S1 + 2 segmentectomy were well-preserved among other segmentectomies and lobectomy. Thoracoscopic S1 + 2 segmentectomy is a good alternative for preserving postoperative function.

Stapled video-assisted thoracoscopic segmentectomy preserves as much lung volume as nonstapled video-assisted thoracoscopic segmentectomy

BACKGROUND

Two different techniques of performing segmentectomy have been reported in the era of video-assisted thoracosopic surgery (VATS), including stapled segmentectomy (SS) and non-stapled segmentectomy (NSS). Some surgeons favor stapled segmentectomy for better pneumostatic control, while others prefer non-stapled segmentectomy to avoid compromising adjacent pulmonary parenchyma. In this study, we used multidetector computed tomography (MDCT) and spirometry to evaluate lung volume preservation of different segmentectomy techniques.

METHODS

A total of 269 patients undergoing video-assisted thoracic surgery (VATS) segmentectomy between October 2013 and September 2016 in a single institution were reviewed. Perioperative outcomes, the cost of hospital admission, the change in forced expiratory volume in 1 s (FEV1) (ΔFEV1 and ΔFEV1%), and residual ipsilateral volume ratios (RiVR) were compared.

RESULTS

The final study population consisted of 107 patients: 30 patients underwent NSS, and 77 patients underwent SS. The NSS group had significantly longer operative time, more blood loss, longer duration of chest tube placement and postoperative hospitalization than the SS group. The follow-up of RiVR (at 6 months, 12 months, 24 months), ΔFEV1(L), and ΔFEV1(%) demonstrated no significant difference between NSS and SS group.

CONCLUSION

Our study demonstrated that postoperative residual lung volume was not influenced by different segmentectomy techniques.

Computed tomography pulmonary angiography and venography with a low dose of contrast medium

The authors developed a method to ensure sufficient opacification of pulmonary vasculature for separate depiction of arteries and veins in three-dimensional form with a small dose of contrast medium utilizing a test injection to determine optimal timing of computed tomography (CT) scanning. The dose was determined by a simulation based on a pharmacokinetic model. The contrast medium was administered at a rate of 5.0 mL/s for 3 s, followed by helical scanning at the timing determined by a dynamic CT scanning following the test injection. Images of 20 consecutive patients acquired with a 64-row CT scanner were evaluated. Quality of vessel depiction was assessed on the basis of the following: HU values at the main pulmonary artery (MPA) and left atrium (LA), distance between the pleural surface and the distal end of the pulmonary vessels on three-dimensional CT pulmonary arteriography and venography (3D-CTPAV), and subjective visual assessment of quality of the 3D-CTPAV images. Time to generate the 3D-CTPAV images was recorded. The mean ± standard deviation (SD) of the HU values at MPA/LA and the distances to the pleural surface for pulmonary arteries/veins were 448.0 ± 123.1/277.3 ± 60.85 HU and 9.21 ± 3.60/10.7 ± 5.45 mm, respectively. The image quality was visually rated as excellent for all of the patients. The mean time ± SD to generate 3D-CTPAV images was 13.6 ± 6.7 min. In conclusion, three-dimensional images of the pulmonary vasculature can be created using 21 mL (including 6 mL for the test injection) of contrast medium.

Video-assisted thoracoscopic subsegmentectomy for small-sized pulmonary nodules

Segmentectomy has been widely performed as one of the types of limited resections that are performed for the resection of small-sized lung nodules. Video-assisted thoracoscopic surgery has also been in demand as a minimally invasive surgery. Subsegmentectomy is a much more limited resection than segmentectomy, but the technique is complex because it requires keen anatomical identification of small pulmonary structures. Therefore, there has been little reported about subsegmentectomy in medical literature. The recent development of computed tomography is remarkable, and some reports describe three-dimensional computed tomography as providing useful information because it assists surgeons in the performance of thoracoscopic anatomical subsegmentectomy. The creation of an intersubsegmental line is a key process in subsegmentectomy, therefore, some methods have been reported. We have safely and accurately performed some video-assisted thoracoscopic subsegmentectomies for small-sized lung tumors, using the three-dimensional computed tomography simulation and creating the intersubsegmental line with the inflation-deflation technique. In this article, we describe the recent techniques and roles of video-assisted thoracoscopic subsegmentectomy, and offer prospects for this procedure with our clinical data.