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

Clinical usefulness of four-dimensional dynamic ventilation CT for borderline resectable locally advanced esophageal cancer

PURPOSE

This study aimed to evaluate the clinical significance of four-dimensional dynamic ventilation CT (4DCT) for assessing resectability in borderline resectable locally advanced esophageal cancer (BR-LAEC) and confirmed the pathological validity of the 4DCT results in surgery without prior treatment.

MATERIALS AND METHODS

We retrospectively reviewed 128 patients (107 men; median age, 68 [range, 43-89] years) diagnosed with BR-LAEC on initial conventional CT (i-CT). These patients were initially classified into three categories: BR1 (closer to resectable), BR2 (resectability not assessable), or BR3 (closer to unresectable). Subsequent 4DCT reclassified patients as either resectable or unresectable within 1 week of i-CT. We analyzed the diagnostic shift induced by 4DCT. Additionally, 18 patients who underwent surgery without prior treatment were evaluated using 4DCT and pathological outcomes.

RESULTS

4DCT reclassified patients with BR-LAEC as resectable (57.0%; 73/128) and unresectable (43.0%; 55/128). Of 53 patients initially classified as BR1, 32.1% (17/53) were reclassified as unresectable, and of 47 patients initially classified as BR3, 46.8% (22/47) were reclassified as resectable. Among 28 patients initially classified as BR2, 53.6% (15/27) were reclassified as resectable and 46.4% (13/27) as unresectable. In the surgery-only cohort of 18 patients, 9 were initially classified as BR1 and 9 as BR2, and all were reclassified as resectable. These patients were pathologically confirmed to have resectable disease.

CONCLUSIONS

4DCT may provide information complementary to that provided by initial conventional CT in assessing resectability among patients with BR-LAEC, and could be a useful adjunct tool for guiding clinical decisions in this patient population.

Diagnostic utility of chest wall vessel involvement sign on ultra-high-resolution CT for primary lung cancer infiltrating the chest wall

OBJECTIVES

Chest wall infiltration in primary lung cancer affects the surgical and therapeutic strategies. This study evaluates the efficacy of the chest wall vessel involvement in subpleural lung cancer (CWVI)　on ultra-high-resolution CT (UHR-CT) for detecting chest wall invasion.

MATERIALS AND METHODS

A retrospective analysis of lung cancer cases with confirmed pleural and chest wall invasion was conducted from November 2019 to April 2022. Seventy-seven patients (mean ± standard deviation age 70 ± 8 years, 64 males) who underwent preoperative contrast-enhanced UHR-CT were included. They were grouped into 51 non-chest wall infiltration (pl1 and pl2) and 26 chest wall infiltration (pl3). Clinical, histopathological, and UHR-CT findings were reviewed.

RESULTS

Upper lobe tumors exhibited a higher chest wall invasion rate (p < 0.001). Rib destruction was evident in five patients with chest wall invasion but none with pleural invasion (p < 0.001). CWVI was present in 19 of 26 patients with chest wall invasion and 2 of 51 patients with pleural invasion (p < 0.001). The maximum tumor diameter (Dmax), arch distance which means the interface length between the primary tumor and the chest wall (Adist), and the ratio of Dmax to Adist were higher in chest wall invasion cases (all p < 0.001). After excluding patients with rib destruction, in multivariate logistic regression analysis, only CWVI was a significant predictor for chest wall invasion (odds ratio 29.22 (95% confidence interval 9.13-262.90), p < 0.001).

CONCLUSION

CWVI on UHR-CT can help diagnose lung cancer infiltrating the chest wall, offering a potential tool for clinical decision-making.

KEY POINTS

Question Chest wall infiltration in primary lung cancer has implications for the treatment plan, but diagnosis is often difficult with conventional CT. Findings Chest wall vessel involvement in subpleural lung cancer on ultra-high-resolution CT is a valuable predictor for diagnosing chest wall infiltration. Clinical relevance The delineation of chest wall vessels with contrast-enhanced ultra-high-resolution CT may improve the diagnosis of chest wall infiltration and allow accurate staging and optimal treatment options for subpleural primary lung cancer.

Preoperative diagnosis of adhesion severity between the abdominal wall and intestinal tract with novel abdominal ultrasound methodology to enhance surgical safety

BACKGROUND

Adhesions between the abdominal wall and intestinal tract from previous surgeries can complicate reoperations; however, predicting the extent of adhesions preoperatively is difficult. This study aimed to develop a straightforward approach for predicting adhesion severity using a novel abdominal ultrasound technique that quantifies the displacement of motion vectors of two organs to enhance surgical safety. The efficacy of this methodology was assessed experimentally and clinically.

METHODS

Using Aplio500T, a system we developed, we measured the displacement of the upper peritoneum and intestinal tract as a vector difference and computed the motion difference ratio. Twenty-five rats were randomized into surgery and nonsurgery groups. The motion difference ratio was assessed 7 days after laparotomy to classify adhesions. In a clinical trial, 51 patients undergoing hepatobiliary pancreatic surgery were evaluated for the motion difference ratio within 3 days preoperatively. Intraoperatively, adhesion severity was rated and compared with the motion difference ratio. A receiver operating characteristic curve was used to appraise the diagnostic value of the motion difference ratio.

RESULTS

In the animal experiment, the adhesion group exhibited a significantly higher motion difference ratio than the no-adhesion group (0.006 ± 0.141 vs 0.435 ± 0.220, P < .001). In the clinical trial, the no-adhesion or no-laparotomy group had a motion difference ratio of 0.128 ± 0.074; mild-adhesion group, 0.143 ± 0.170; moderate-adhesion group, 0.326 ± 0.153; and high-adhesion group, 0.427 ± 0.152. The motion difference ratio receiver operating characteristic curve to diagnose the adhesion level (≥moderate) was 0.938, indicating its high diagnostic value (cut-off 0.204).

CONCLUSION

This methodology may preoperatively predict moderate-to-high adhesions.

Right main pulmonary artery distensibility on dynamic ventilation CT and its association with respiratory function

BACKGROUND

Heartbeat-based cross-sectional area (CSA) changes in the right main pulmonary artery (MPA), which reflects its distensibility associated with pulmonary hypertension, can be measured using dynamic ventilation computed tomography (DVCT) in patients with and without chronic obstructive pulmonary disease (COPD) during respiratory dynamics. We investigated the relationship between MPA distensibility (MPAD) and respiratory function and how heartbeat-based CSA is related to spirometry, mean lung density (MLD), and patient characteristics.

METHODS

We retrospectively analyzed DVCT performed preoperatively in 37 patients (20 female and 17 males) with lung cancer aged 70.6 ± 7.9 years (mean ± standard deviation), 18 with COPD and 19 without. MPA-CSA was separated into respiratory and heartbeat waves by discrete Fourier transformation. For the cardiac pulse-derived waves, CSA change (CSAC) and CSA change ratio (CSACR) were calculated separately during inhalation and exhalation. Spearman rank correlation was computed.

RESULT

In the group without COPD as well as all cases, CSACR exhalation was inversely correlated with percent residual lung volume (%RV) and RV/total lung capacity (r = -0.68, p = 0.003 and r = -0.58, p = 0.014). In contrast, in the group with COPD, CSAC inhalation was correlated with MLDmax and MLD change rate (MLDmax/MLDmin) (r = 0.54, p = 0.020 and r = 0.64, p = 0.004) as well as CSAC exhalation and CSACR exhalation.

CONCLUSION

In patients with insufficient exhalation, right MPAD during exhalation was decreased. Also, in COPD patients with insufficient exhalation, right MPAD was reduced during inhalation as well as exhalation, which implied that exhalation impairment is a contributing factor to pulmonary hypertension complicated with COPD.

RELEVANCE STATEMENT

Assessment of MPAD in different respiratory phases on DVCT has the potential to be utilized as a non-invasive assessment for pulmonary hypertension due to lung disease and/or hypoxia and elucidation of its pathogenesis.

KEY POINTS

• There are no previous studies analyzing all respiratory phases of right main pulmonary artery distensibility (MPAD). • Patients with exhalation impairment decreased their right MPAD. • Analysis of MPAD on dynamic ventilation computed tomography contributes to understanding the pathogenesis of pulmonary hypertension due to lung disease and/or hypoxia in patients with expiratory impairment.

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.

Preoperative evaluation of pleural adhesions with dynamic chest radiography: a retrospective study of 146 patients with lung cancer

AIM

To assess the utility of dynamic chest radiography (DCR) during the preoperative evaluation of pleural adhesions.

MATERIALS AND METHODS

Sequential chest radiographs of 146 patients with lung cancer were acquired during forced respiration using a DCR system. The presence of pleural adhesions and their grades were determined by retrospective surgery video assessment (absent: 121, present: 25). The maximum inspiration to expiration lung area ratio was used as an index for air intake volume. A ratio of ≥0.65 was regarded as insufficient respiration. Two radiologists assessed the images for pleural adhesions based on motion findings. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were compared for each adhesion grade and patient group (patients with sufficient/insufficient respiration). Pearson's chi-squared test compared the group. Statistical significance was set at p<0.05.

RESULTS

DCR correctly identified 22/25 patients with pleural adhesions, with 20 false-positive results (sensitivity, 88%; specificity, 83.5%; PPV, 52.4%; NPV, 97.12%). Although the diagnostic performances for the various adhesion grades were similar, specificity in patients with sufficient respiration increased to 93.9% (31/33), identifying all cases except for those with loose adhesions.

CONCLUSIONS

DCR images revealed restricted and/or distorted motions in lung structures and structural tension in patients with pleural adhesions. DCR could be a useful technique for routine preoperative evaluation of pleural adhesions. Further development of computerised methods can assist in the quantitative assessment of abnormal motion findings.

Preoperative evaluation of pleural adhesion in patients with lung tumors using four-dimensional computed tomography performed during natural breathing

The presence of pleural adhesions increases blood loss, occurrence of pulmonary fistulation due to lung injury, and operative time and may complicate thoracoscopic surgery. Recently, it has been reported that four-dimensional computed tomography (4D-CT) synchronized with breathing predicts pleural adhesion. These studies have been performed by asking the patients to maintain a constant respiratory rhythm at the time of scanning. However, many patients face difficulty in doing so, particularly elderly individuals and patients with respiratory dysfunction. We examined the utility of 4D-CT performed while maintaining a natural breathing pattern, which reduces patient burden, in detecting pleural adhesions.A total of 36 patients with a lung tumor near the pleura underwent 4D-CT during free breathing. The migration distance between the lesion and the nearest point on the chest wall on 4D-CT was measured. A sufficient distance indicated the absence of adhesion in that area. The presence of actual adhesions was evaluated and confirmed by intraoperative thoracoscopic findings.There were 7 cases determined to have adhesion by 4D-CT, and 4 of them had actual adhesions confirmed during surgery. The sensitivity and specificity were 80.0% and 90.3%, respectively. The mean migration distance of tumors was 0.8 ± 0.2 cm in the 5 cases with adhesion and 2.6 ± 1.8 cm in the 31 cases without adhesion (P = .01).These results suggest that 4D-CT is a convenient and useful technique for the preoperative assessment of pleural adhesion.

Preoperative prediction of the localization of a solitary fibrous tumor using four-dimensional computed tomography: a case report

Solitary fibrous tumors of the pleura (SFTP) are relatively rare primary pleural tumors. Four-dimensional computed tomography (4D-CT) is reportedly useful in assessing parietal pleural invasion and adhesion in patients with lung cancer. We report a case in which 4D-CT was performed to evaluate SFTP localization and parietal pleural invasion and adhesions. A 62-year-old female presented with an abnormality on a chest radiograph. Chest CT revealed a well-demarcated solid nodule in the left lower lobe adjacent to the pleura. We considered that the tumor was intrapulmonary or arose from the visceral pleura, without adhesion or invasion to the chest wall based on 4D-CT. Primary lung cancer was suspected, and the tumor was resected. Pathological diagnosis revealed an SFTP. This case suggests that 4D-CT is useful in predicting the localization of SFTP and other thoracic tumors, assessing chest wall adhesion and invasion, and making surgical strategies.

The Intrapleural Bridge Connection is One of the Reasons for Unknown Localized Pleural Adhesion

Background

Simple signs of local pleural adhesion are often found in people during a physical examination. In the present study, we aimed to clarify whether the merely localized pleural adhesion was just caused by previous pleural inflammation or physiological variation.

Materials and Methods

Chest X-ray image materials were collected to analyze the incidence of simple pleural adhesions. Moreover, the causes of these simple pleural adhesions were further analyzed using thoracoscopy under direct vision and biopsy data.

Results

In all 2218 chest X-ray images, 68 cases were found to have pleural lesions (3.07%), including 15 cases of localized pleural adhesion only. Subsequently, we analyzed the characteristics of 70 cases of pleural lesions using thoracoscopy. In two lung cancer patients with pleural metastasis, we found an unusual pleural junction. This connective strip was smooth and free of inflammation, resembling the normal pleura.

Conclusion

Some of these purely localized pleural adhesions might be attributed to previous inflammation. However, there was still at least a possibility that there must be a physiological pleural junction, which could be the cause of the purely localized pleural adhesion shown in the chest radiograph.

Assessment of pleural invasion and adhesion of lung tumors with dynamic chest radiography: A virtual clinical imaging study

PURPOSE

Accurate preoperative assessment of tumor invasion/adhesion is crucial for planning appropriate operative procedures. Recent advances in digital radiography allow a motion analysis of lung tumors with dynamic chest radiography (DCR) with total exposure dose comparable to that of conventional chest radiography. The aim of this study was to investigate the feasibility of preoperative evaluation of pleural invasion/adhesion of lung tumors with DCR through a virtual clinical imaging study, using a four-dimensional (4D) extended cardiac-torso (XCAT) computational phantom.

METHODS

An XCAT phantom of an adult man (50th percentile in height and weight) with simulated respiratory and cardiac motions was generated to use as a virtual patient. To simulate lung tumors with and without pleural invasion, a 30-mm diameter tumor sphere was inserted into each lobe of the phantom. The virtual patient during respiration was virtually projected using an x-ray simulator in posteroanterior (PA) and oblique directions, and sequential bone suppression (BS) images were created. The measurement points (tumor, rib, and diaphragm) were automatically tracked on simulated images by a template matching technique. We calculated five quantitative metrics related to the movement distance and directions of the targeted tumor and evaluated whether DCR could distinguish between tumors with and without pleural invasion/adhesion.

RESULTS

Precise tracking of the targeted tumor was achieved on the simulated BS images without undue influence of rib shadows. There was a significant difference in all five quantitative metrics between the lung tumors with and without pleural invasion both on the oblique and PA projection views (P < 0.05). Quantitative metrics related to the movement distance were effective for tumors in the middle and lower lobes, while, those related to the movement directions were effective for tumors close to the frontal chest wall on the oblique projection view. The oblique views were useful for the evaluation of the space between the chest wall and a moving tumor.

CONCLUSION

DCR could help distinguish between tumors with and without pleural invasion/adhesion based on the two-dimensional movement distance and direction using oblique and PA projection views. With anticipated improved image: processing to evaluate the respiratory displacement of lung tumors in the upper lobe or behind the heart, DCR holds promise for clinical assessment of tumor invasion/adhesion in the parietal pleura.

Application of Polarization Sensitive-Optical Coherence Tomography to the Assessment of Phase Retardation in Subpleural Cancer in Rabbits

BACKGROUND

Polarization sensitive-optical coherence tomography (PS-OCT) provides the unique advantage of being able to measure the optical characteristics of tissues by using polarized light. Although the well-organized fibers of healthy muscle can change the polarization states of passing light, damaged tissue has different behaviors. There are studies on optical imaging methods applied to the respiratory organs; however, they are restricted to structural imaging. In particular, the intercostal muscle situated under the pleura is very challenging to visualize due to the difficulty of access.

METHOD

In this study, PS-OCT was used to identify subpleural cancer in male New Zealand white rabbits (3.2-3.4 kg) and to assess the phase retardation changes in normal and cancerous chest walls. VX2 cell suspension was injected between the intercostal muscle and parietal pleura and a tented area was observed by thoracic scope. A group of rabbits (n = 3) were sacrificed at day 7 after injection and another group (n = 3) at day 14.

RESULTS

In the PS-OCT images, pleura thickness changes and muscle damage were criteria to understand the stages of the disease. The results of image and phase retardation analysis matched well with the pathologic examinations.

CONCLUSION

We were able to visualize and analyze subpleural cancer by PS-OCT, which provided structural and functional information. The measured phase retardation could help to identify the margin of the tumor. For further studies, various approaches into other diseases using polarization light are expected to have positive results.

Case report: uniportal video-assisted thoracoscopic resection of a solitary fibrous tumor preoperatively predicted visceral pleura origin using dynamic chest radiography

Background

Dynamic chest radiography (DCR) is a flat-panel detector (FPD)-based functional X-ray imaging, which is performed as an additional examination in chest radiography. DCR provides objective and quantifiable information, such as diaphragm movement, pulmonary ventilation and circulation, and is reasonable for detecting tumor invasion or adhesion.

Case presentation

We present a case of Solitary Fibrous Tumor of Pleura (SFTP), preoperatively predicted visceral pleura origin using Dynamic chest radiography (DCR) and surgically resected through single-access (uniportal) video-assisted thoracoscopic surgery (UVATS).

Conclusions

UVATS may be a suitable surgical option for pedunculated SFTPs. Dynamic chest radiography provides information, such as tumor invasion or adhesion and helpful for predicting origin of the tumor.

Dynamic chest radiography: Novel and less-invasive imaging approach for preoperative assessments of pleural invasion and adhesion

Here, we report a case of lung cancer with preoperatively predicted invasion to the parietal pleura on dynamic chest radiography (DCR). An 82-year-old patient was referred for staging of a right lung tumor. Preoperative DCR revealed invasion or adhesion of the tumor to the chest wall, and intraoperative findings revealed invasion of the tumor to the parietal pleura. DCR provides objective and quantifiable information, including diaphragmatic movement, pulmonary ventilation, and circulation, as well as tumor invasion or adhesion and is less invasive compared to 3-dimensional chest computed tomography or cine magnetic resonance imaging. This study was our initial attempt at performing a quantitative assessment using DCR.

[Method for Spectral Analysis of the Respiratory Cycle Based on Dynamic Pulmonary Computed Tomography]

Dynamic pulmonary computed tomography (CT) enables morphological analyses of tumor adhesion and infiltration and functional analyses of the lungs based on four-dimensional data. However, the functional analysis requires visualization of the respiratory cycle. The aim of the present study was to investigate the utility of spectral analysis as part of the functional analysis of the lungs based on dynamic pulmonary CT. In this study, the reference curves for the respiratory cycle were obtained using measurements of all phases of respiration based on the movement of the diaphragm. The reference curves and fields of the unaffected lung were divided into three sections: upper, middle, and lower. The central position within each lung field in the axial section was used as the fixed location, and the lung field concentrations (CT values within each lung field) were measured. Using the maximum entropy (ME) method, the spectral analysis was performed for the lung field concentration curves obtained in this manner. The investigated items were the peak frequency in the power spectrum based on the ME analysis of the reference curve and the time difference from this peak frequency in the upper, middle, and lower lung field concentration curves. The time differences (median±standard deviation) from the reference values were 0.18±0.20, 0.34±0.33, and 0.34±0.35 s in the upper, middle, and lower lung fields, respectively, indicating the smallest time difference in the upper lung field. Performing spectral analysis using the ME method on lung field concentration curves enables assessment of the respiratory cycle based on dynamic pulmonary CT, and this approach is consistent with the visual assessment of the respiratory cycle.

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.

Continuous quantitative measurement of the main bronchial dimensions and lung density in the lateral position by four-dimensional dynamic-ventilation CT in smokers and COPD patients

Purpose

The purpose of this study was to measure changes in lung density and airway dimension in smokers in the lateral position using four-dimensional dynamic-ventilation computed tomography (CT) during free breathing and to evaluate their correlations with spirometric values.

Materials and methods

Preoperative pleural adhesion assessments included dynamic-ventilation CT of 42 smokers (including 22 patients with COPD) in the lateral position, with the unoperated lung beneath (dependent lung). The scanned lungs' mean lung density (MLD) and the bilateral main bronchi's luminal areas (Ai) were measured automatically (13-18 continuous image frames, 0.35 seconds/frame). Calculations included cross-correlation coefficients (CCCs) between the MLD and Ai time curves, and correlations between the quantitative measurements and spirometric values were evaluated by using Spearman's rank coefficient.

Results

The ΔMLD_1.05 (from the peak inspiration frame to the third expiratory frame, 1.05 seconds later) in the nondependent lung negatively correlated with FEV₁/FVC (r=-0.417, P<0.01), suggesting that large expiratory movement of the nondependent lung would compensate limited expiratory movement of the dependent lung due to COPD. The ΔAi_1.05 negatively correlated with the FEV₁/FVC predicted in both the lungs (r=-0.465 and -0.311, P<0.05), suggesting that early expiratory collapses of the main bronchi indicate severe airflow limitation. The CCC correlated with FEV₁/FVC in the dependent lung (r=-0.474, P<0.01), suggesting that reduced synchrony between the proximal airway and lung occurs in patients with severe airflow limitation.

Conclusion

In COPD patients, in the lateral position, the following abnormal dynamic-ventilation CT findings are associated with airflow limitation: enhanced complementary ventilation in the nondependent lung, early expiratory airway collapses, and reduced synchrony between airway and lung movements in the dependent lung.

[Development of Audio Indicator System for Respiratory Dynamic CT Imaging]

We created the device, which can conduct a radiological technologist's voice to a subject during CT scanning. For 149 lung cancer, dynamic respiratory CT were performed. 92 cases were performed using this device, the others were without this device. The respiratory cycle and respiratory amplitude were analyzed from the lung density. A stable respirating cycle was obtained by using the audio indicator system. The audio indicator system is useful for respiratory dynamic CT.

A hybrid patient-specific biomechanical model based image registration method for the motion estimation of lungs

This paper presents a new hybrid biomechanical model-based non-rigid image registration method for lung motion estimation. In the proposed method, a patient-specific biomechanical modelling process captures major physically realistic deformations with explicit physical modelling of sliding motion, whilst a subsequent non-rigid image registration process compensates for small residuals. The proposed algorithm was evaluated with 10 4D CT datasets of lung cancer patients. The target registration error (TRE), defined as the Euclidean distance of landmark pairs, was significantly lower with the proposed method (TRE = 1.37 mm) than with biomechanical modelling (TRE = 3.81 mm) and intensity-based image registration without specific considerations for sliding motion (TRE = 4.57 mm). The proposed method achieved a comparable accuracy as several recently developed intensity-based registration algorithms with sliding handling on the same datasets. A detailed comparison on the distributions of TREs with three non-rigid intensity-based algorithms showed that the proposed method performed especially well on estimating the displacement field of lung surface regions (mean TRE = 1.33 mm, maximum TRE = 5.3 mm). The effects of biomechanical model parameters (such as Poisson's ratio, friction and tissue heterogeneity) on displacement estimation were investigated. The potential of the algorithm in optimising biomechanical models of lungs through analysing the pattern of displacement compensation from the image registration process has also been demonstrated.