Respiratory dynamic magnetic resonance imaging for determining aortic invasion of thoracic neoplasms

Investigating the predictive factors of thoracic aortic invasion and surgical outcomes in patients with primary lung cancer: A retrospective study

BACKGROUND

This study aimed to investigate predictors of thoracic aortic invasion in lung cancer patients using preoperative clinical and imaging characteristics and elucidate surgical outcomes in cases of aortic invasion.

METHODS

Of the 4751 lung cancer patients who underwent surgery at our hospital, we included 126 (6.8%) who underwent left-sided surgery and in whom tumor appeared to be in contact with the thoracic aorta on preoperative imaging. The patients were divided into two groups: group A, 23 patients (18%) who underwent combined aortic resection (+); group B, 103 patients (82%) who did not undergo combined aortic resection (-).

RESULTS

The percentage of aortic invasion for tumor diameter <3 cm, 3-4 cm, 4-5 cm, 5-7 cm, and >7 cm was 0%, 13%, 23%, 16%, and 35%, respectively. The percentages of aortic invasion were 27%, 16%, and 0% for tumor localization in the upper division, S6, and S10, respectively. Multivariate analysis revealed that aortic depression due to tumor or loss of fatty tissue between tumor and mediastinum in the chest CT significantly predicted aortic invasion (odds ratio = 23.83, 16.66). Group A demonstrated significantly more blood loss, longer operative time, prolonged hospital stay, and increased percentage of recurrent nerve palsy (13%) compared to group B. The 1-, 3-, and 5-year survival rates for patients in group A were 53.4%, 24.3%, and 24.3%, respectively.

CONCLUSION

If the chest CT of a patient demonstrates aortic depression due to tumor or loss of fatty tissue between tumor and mediastinum, aortic complications should be considered when planning surgery.

T4 Lung Carcinoma with Infiltration of the Thoracic Aorta: Indication and Surgical Procedure

Lung carcinomas infiltrate the aorta mostly on the left side and are altogether rare. As an initial step, complete staging is performed and the results are evaluated in an interdisciplinary tumor board. If the patient's general condition including cardiopulmonary reserves is sufficient, and if there is neither distant metastasis nor an N2 situation, surgical resection may be indicated. The option for neoadjuvant chemotherapy should always be taken into consideration. Depending on the anatomic tumor location, partial lung resection and resection of the affected aortic wall are performed employing a cardiopulmonary bypass. The resected aortic wall is replaced by a vascular prosthesis. In recent years, this proven procedure has partly been replaced by an alternative one, avoiding extracorporeal circulation. An endoaortic stent is implanted in the affected area followed by partial lung resection and resection of the diseased aortic wall. This new procedure has significantly reduced perioperative mortality and morbidity. With proper patient selection, long-term survival can be improved even in this complex malignoma.

The preoperative assessment of thoracic wall adhesions using four-dimensional computed tomography

OBJECTIVE

Pleural adhesions are challenging during lung cancer surgery and may be associated with a long surgery time and excessive blood loss due to pleural adhesiolysis. We used preoperative four-dimensional computed tomography to quantitatively assess parietal pleural adhesions and determine its diagnostic accuracy.

METHODS

A total of 216 patients with lung cancer underwent four-dimensional computed tomography during the study period. Pleural adhesions were subsequently confirmed by surgery in 85 of these patients, whereas 126 patients had no adhesions. The movements of the tumor or target vessels (α) was tracked. Receiver-operating characteristic curve analysis was used to identify the relationship between adhesions and (α).

RESULTS

The movement of (α) was smaller in patients with adhesions than in those without adhesions. The greater the adhesion, the shorter the movement distance (p < 0.001). Receiver-operating characteristic curve analysis demonstrated an area under the curve for the moving (α) point at 0.71 (95% confidence interval: 0.62-0.80) in the upper lung field and at 0.75 (95% confidence interval: 0.64-0.85) in the lower field. To identify adhesions, a cut off of 11.3 mm (sensitivity = 43.6%, specificity = 93.2%) in the upper lung field and a cut off of 41.2 mm (sensitivity = 71.4%, specificity = 66.0%) in the lower lung field were established.

CONCLUSIONS

Four-dimensional computed tomography is a novel and helpful modality for predicting the presence of parietal pleural adhesions. To obtain robust evidence, further accumulation of cases and re-examination of the analysis methods are needed.

Endobronchial ultrasound for T4 staging in patients with resectable NSCLC

BACKGROUND

In lung cancer patients, accurate assessment of mediastinal and vascular tumor invasion (stage T4) is crucial for optimal treatment allocation and to prevent unnecessary thoracotomies. We assessed the diagnostic accuracy of linear endobronchial ultrasound (EBUS) for T4-status in patients with centrally located lung cancer.

METHODS

This is a retrospective study among consecutive patients who underwent EBUS for diagnosis and staging of lung cancer in four hospitals in The Netherlands (Amsterdam, Leiden), Italy (Bologna) and Poland (Zakopane) between 04-2012 and 04-2019. Patients were included if the primary tumor was detected by EBUS and subsequent surgical-pathological staging was performed, which served as the reference standard. T4-status was extracted from EBUS and pathology reports. Chest CT's were re-reviewed for T4-status.

RESULTS

104 patients with lung cancer in whom EBUS detected the primary tumour, and who underwent subsequent surgical-pathological staging were included. 36 patients (35 %) had T4-status, based on vascular (n = 17), mediastinal (n = 15), both vascular and mediastinal (n = 3), or oesophageal invasion (n = 1). For EBUS, sensitivity, specificity, PPV and NPV for T4-status were (n = 104): 63.9 % (95 %CI 46.2-79.2 %), 92.6 % (83.7-97.6 %), 82.1 % (65.6-91.7 %), and 82.9 % (75.7-88.2 %), respectively. For chest CT (n = 72): 61.5 % (95 %CI 40.6-79.8 %), 37.0 % (23.2-52.5 %), 35.6 % (27.5-44.6 %), and 63.0 % (47.9-75.9 %), respectively. When combining CT and EBUS with concordant T4 status (n = 33): 90.9 % (95 %CI 58.7-99.8 %), 77.3 % (54.6-92.20 %), 66.7 % (47.5-81.6 %), and 94.4 % (721-99.1%), respectively.

CONCLUSION

Both EBUS and CT alone are inaccurate for assessing T4-status as standalone test. However, combining a negative EBUS with a negative CT may rule out T4-status with high certainty.

The preoperative assessment of subpleural lung cancer movement to distinguish thoracic wall adhesion or invasion using four-dimensional computed-tomography

Four-dimensional computed tomography (4DCT) is a relatively new technology. A review of the relevant medical literature reveals only very limited previous investigations of the utility of this technique. We report two cases of lung cancer located adjacent to the pleura in which 4DCT was used to assess parietal pleural invasion or adhesion based on the differential movements of tumors. We performed 4DCT to determine the surgical approach after obtaining appropriate informed consent from the patient. Based on 4DCT, Patient 1 showed there was no adhesion and we could perform thoracoscopic right lower lobectomy and the final pathological diagnosis was pT1bN0M0. Patient 2 Based on 4DCT, showed suspicious of invasion or adhesion. we performed chest wall resection because of tumor invasion in the eighth and ninth costal bones; a final pathological diagnosis of pT3N0M0 was made.

Building blocks for thoracic MRI: Challenges, sequences, and protocol design

Thoracic MRI presents important and unique challenges. Decreased proton density in the lung in combination with respiratory and cardiac motion can degrade image quality and render poorly executed sequences uninterpretable. Despite these challenges, thoracic MRI has an important clinical role, both as a problem-solving tool and in an increasing array of clinical indications. Advances in scanner and sequence design have also helped to drive this development, presenting the radiologist with improved techniques for thoracic MRI. Given this evolving landscape, radiologists must be familiar with what thoracic MR has to offer. The first step in developing an effective thoracic MRI practice requires the creation of efficient and malleable protocols that can answer clinical questions. To do this, radiologists must have a working knowledge of the MR sequences that are used in the thorax, many of which have been adapted from use elsewhere in the body. These sequences can be broadly divided into three categories: traditional/anatomic, functional, and cine based. Traditional/anatomic sequences allow for the depiction of anatomy and pathologic processes with the ability for characterization of signal intensity and contrast enhancement. Functional sequences, including diffusion-weighted imaging, and high temporal resolution dynamic contrast enhancement, allow for the noninvasive measurement of tissue-specific parameters. Cine-based sequences can depict the motion of structures in the thorax, either with retrospective ECG gating or in real time. The purpose of this article is to review these categories, the building block sequences that comprise them, and identify basic questions that should be considered in thoracic MRI protocol design. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:682-701.

Four-Dimensional Thoracic CT in Free-Breathing Children

In pediatric thoracic CT, respiratory motion is generally treated as a motion artifact degrading the image quality. Conversely, respiratory motion in the thorax can be used to answer important clinical questions, that cannot be assessed adequately via conventional static thoracic CT, by utilizing four-dimensional (4D) CT. However, clinical experiences of 4D thoracic CT are quite limited. In order to use 4D thoracic CT properly, imagers should understand imaging techniques, radiation dose optimization methods, and normal as well as typical abnormal imaging appearances. In this article, the imaging techniques of pediatric thoracic 4D CT are reviewed with an emphasis on radiation dose. In addition, several clinical applications of pediatric 4D thoracic CT are addressed in various thoracic functional abnormalities, including upper airway obstruction, tracheobronchomalacia, pulmonary air trapping, abnormal diaphragmatic motion, and tumor invasion. One may further explore the clinical usefulness of 4D thoracic CT in free-breathing children, which can enrich one's clinical practice.

Preoperative detection of pleural adhesions by respiratory dynamic computed tomography

BACKGROUND

Video-assisted thoracic surgery (VATS) plays an important role in thoracic surgery because it is less invasive. However, the existence of severe pleural adhesions may make VATS difficult and complicated. The aim of this study was to assess the utility of inspiration and expiration computed tomography (respiratory dynamic CT (RD-CT)) in evaluation of pleural adhesions preoperatively.

METHODS

RD-CT was performed on 107 patients undergoing thoracotomies (both VATS and open). We assessed synchronous motion during respiration on RD-CT. Comparing the results of RD-CT and intraoperative findings, we assessed the utility of preoperative evaluation.

RESULTS

A negative correlation between sliding score and adhesion grade was revealed. Sliding score in adhesion negative patients was significantly higher than that in adhesion positive patients (P < 0.0001). The sensitivity of RD-CT was 63.6%, specificity was 74.1%, and accuracy was 72%. Among 62 patients with a CT-Respiration Ratio of less than 0.65, the sensitivity of RD-CT was 77.8%, specificity was 86.8%, and accuracy was 85.5%.

CONCLUSIONS

RD-CT may be clinically useful for detecting the presence of pleural adhesions. It can be adopted as one of the criteria for deciding the surgical approach.

Parietal pleural invasion/adhesion of subpleural lung cancer: Quantitative 4-dimensional CT analysis using dynamic-ventilatory scanning

PURPOSE

Using 4-dimensional dynamic-ventilatory scanning by a 320-row computed tomography (CT) scanner, we performed a quantitative assessment of parietal pleural invasion and adhesion by peripheral (subpleural) lung cancers.

METHODS

Sixteen patients with subpleural lung cancer underwent dynamic-ventilation CT during free breathing. Neither parietal pleural invasion nor adhesion was subsequently confirmed by surgery in 10 patients, whereas the other 6 patients were judged to have parietal pleural invasion or adhesion. Using research software, we tracked the movements of the cancer and of an adjacent structure such as the rib or aorta, and converted the data to 3-dimensional loci. The following quantitative indices were compared by the Mann-Whitney test: cross-correlation coefficient between time curves for the distances moved from the inspiratory frame by the cancer and the adjacent structure, the ratio of the total movement distances (cancer/adjacent structure), and the cosine similarities between the inspiratory and expiratory vectors (from the cancer to the adjacent structure) and between vectors of the cancer and of the adjacent structure (from inspiratory to expiratory frames).

RESULTS

Generally, the movements of the loci of the lung cancer and the adjacent structure were similar in patients with parietal pleural invasion/adhesion, while they were independent in patients without. There were significant differences in all the parameters between the two patient groups (cross-correlation coefficient and the movement distance ratio, P<0.01; cosine similarities, P<0.05).

CONCLUSION

These observations suggest that quantitative indices by dynamic-ventilation CT can be utilized as a novel imaging approach for the preoperative assessment of parietal pleural invasion/adhesion.

Emerging Role of MRI for Radiation Treatment Planning in Lung Cancer

Magnetic resonance imaging (MRI) provides excellent soft-tissue contrast and allows for specific scanning sequences to optimize differentiation between various tissue types and properties. Moreover, it offers the potential for real-time motion imaging. This makes magnetic resonance imaging an ideal candidate imaging modality for radiation treatment planning in lung cancer. Although the number of clinical research protocols for the application of magnetic resonance imaging for lung cancer treatment is increasing (www.clinicaltrials.gov) and the magnetic resonance imaging sequences are becoming faster, there are still some technical challenges. This review describes the opportunities and challenges of magnetic resonance imaging for radiation treatment planning in lung cancer.