Dynamic four-dimensional computed tomography for preoperative assessment of lung cancer invasion into adjacent structures†

Abstract

OBJECTIVES: The 320-slice computed tomography (CT) provides three-dimensional and dynamic imaging resulting in the ability to assess motion analysis between two adjacent structures (the fourth dimension). Differential movements between two adjacent structures would indicate that there is no fixation between the two structures. METHODS:Eight patients with non-small-cell lung cancers located adjacent to vital structures (e.g. the great vessels) (n = 4), mediastinum (n = 1) or chest wall (n = 3) where conventional CT was unable to exclude local invasion underwent dynamic four-dimensional (4D) CT assessment. In 3 patients, the lung tumour was abutting the chest wall and 1 patient had tumour abutting the mediastinum. The remaining patients included a patient with a large 14-cm left lower lobe cancer abutting the descending thoracic aorta who had previous pleurodesis; a patient with an apical right upper lobe 6-cm cancer with static imaging appearances suggestive of tumour invasion into the apex, the mediastinal surface and superior vena cava (SVC); a patient with a 3.5-cm cancer which had a broad 2.5-cm base abutting the distal aortic arch and a patient with a 14-cm left upper lobe cancer abutting the aortic arch, descending thoracic aorta and chest wall. Differential movements between the tumour and adjacent structure on 4D CT were considered indicative of the absence of frank invasion.RESULTS: Dynamic 4D imaging revealed differential movements between the tumour and the adjacent structures in 7 cases, suggesting the absence of overt malignant invasion. Intraoperative assessments confirmed the findings. In 1 case, a small area of fixation seen on dynamic CT corresponded intraoperatively to superficial invasion of the adventitia of the SVC.CONCLUSIONS: Dynamic 4D 320-slice CT is useful in the preoperative assessment of the direct invasion of lung cancer into adjacent structures and hence its resectability.

Prediction of pleural invasion using different imaging tools in non-small cell lung cancer

“…The speed and spatial resolution of the 320-slice CT make it a useful and non-invasive tool for the initial evaluation of cardiac disease. Choong et al (23) tried to use 320-slice CT for detecting invasion of lung tumors into the adjacent structures and termed as dynamic fourdimensional CT (4D CT); eight cases of NSCLC were evaluated. They revealed that this modality may be useful in the preoperative assessment of invasion into adjacent structures.…”

“…However, CXR is not suitable for assessing pleural invasion in early stage NSCLC. Ultrasound (US) (9,10), computed tomography (CT) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), magnetic resonance imaging (MRI) (22,23) and fluorine-18-fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET) (24)(25)(26) have been used for preoperative prediction of pleural invasion. However, no single imaging method has been proposed for the definitive diagnosis of pleural invasion, and each imaging modality has its advantages as well as limitations ( Figure 3).…”

Four-Dimensional Thoracic CT in Free-Breathing Children

“…Such information regarding the number of phases per second is lacking in other pediatric 4D thoracic CT studies. On the other hand, 4D thoracic CT using a 320-slice CT scanner was performed with image acquisition of six phases per second in approximately 7 seconds to cover two respiratory cycles in eight adult patients with lung cancer (18). Such an adult protocol delivering high radiation dose should be modified to a pediatric protocol with particular attention to radiation dose.…”

“…Dynamic 4D CT may also be used for this purpose. In the initial clinical experience in a small number of adult patients with lung cancer (18), 4D CT could reveal differential movements between the tumor and the adjacent structures in seven patients without direct invasion, as well as a small area of fixation due to superficial invasion of the adventitia of the superior vena cava in one case. There has been no such 4D CT study in children.…”

The usefulness of radiographic imaging for predicting the resectability of thymic carcinoma

“…There have also been some studies in which the dynamic imaging of the cardiothoracic region has been used to analyze the motion of tumors and the adjacent structures. Four-dimensional (4D)-CT or cine-magnetic resonance imaging (MRI) have also been used to improve diagnostic accuracy in such cases, especially to visualize the motion derived from respiration, or the pulsation of cardiovascular structures (10)(11)(12)(13)(14). Both the CT and the MRI, have been reported to be useful for diagnosing tumor invasion; however, it is difficult to assess tumor invasion into adjacent blood vessels on a non-contrast-enhanced CT.…”