Retrodiaphragmatic portion of the lung: how deep is the posterior costophrenic sulcus on posteroanterior chest radiography?

IA-Body Composition CT at T12 in Idiopathic Pulmonary Fibrosis: Diagnosing Sarcopenia and Correlating with Other Morphofunctional Assessment Techniques

BACKGROUND

Body composition (BC) techniques, including bioelectrical impedance analysis (BIVA), nutritional ultrasound® (NU), and computed tomography (CT), can detect nutritional diagnoses such as sarcopenia (Sc). Sc in idiopathic pulmonary fibrosis (IPF) is associated with greater severity and lower survival. Our aim was to explore the correlation of BIVA, NU and functional parameters with BC at T12 level CT scans in patients with IPF but also its relationship with degree of Sc, malnutrition and mortality.

METHODS

This bicentric cross-sectional study included 60 IPF patients (85.2% male, 70.9 ± 7.8 years). Morphofunctional assessment (MFA) techniques included BIVA, NU, CT at T12 level (T12-CT), handgrip strength, and timed up and go. CT data were obtained using FocusedON®. Statistical analysis was conducted using JAMOVI version 2.3.22 to determine the cutoff points for Sc in T12-CT and to analyze correlations with other MFA techniques.

RESULTS

the cutoff for muscle area in T12-CT was ≤77.44 cm2 (area under the curve (AUC) = 0.734, sensitivity = 41.7%, specificity = 100%). The skeletal muscle index (SMI_T12CT) cutoff was ≤24.5 cm2/m2 (AUC = 0.689, sensitivity = 66.7%, specificity = 66.7%). Low SMI_T12CT exhibited significantly reduced median survival and higher risk of mortality compared to those with normal muscle mass (SMI cut off ≥ 28.8 cm/m2). SMI_T12CT was highly correlated with body cell mass from BIVA (r = 0.681) and rectus femoris cross-sectional area (RF-CSA) from NU (r = 0.599). Cronbach's α for muscle parameters across different MFA techniques and CT was 0.735, confirming their validity for evaluating muscle composition.

CONCLUSIONS

T12-CT scan is a reliable technique for measuring low muscle mass in patients with IPF, specifically when the L3 vertebrae are not captured. An SMI value of <28.8 is a good predictor of low lean mass and 12-month mortality in IPF patients.

Considerations for Imaging of Malignant Pleural Mesothelioma: A Consensus Statement from the International Mesothelioma Interest Group

Malignant pleural mesothelioma (MPM) is an aggressive primary malignancy of the pleura that presents unique radiologic challenges with regard to accurate and reproducible assessment of disease extent at staging and follow-up imaging. By optimizing and harmonizing technical approaches to imaging MPM, the best quality imaging can be achieved for individual patient care, clinical trials, and imaging research. This consensus statement represents agreement on harmonized, standard practices for routine multimodality imaging of MPM, including radiography, computed tomography, ¹⁸F-2-deoxy-D-glucose positron emission tomography, and magnetic resonance imaging, by an international panel of experts in the field of pleural imaging assembled by the International Mesothelioma Interest Group. In addition, modality-specific technical considerations and future directions are discussed. A bulleted summary of all technical recommendations is provided.

Large pneumothorax following thoracic and lumbar tumor surgery: Risk factors and management strategies

Objective

Large pneumothorax is a rare but dangerous complication following thoracic and lumbar tumor surgery. There is little discussion about the features of large pneumothorax following spinal tumor surgery. The purpose of this study was to analyze the characteristics of postoperative pneumothorax, identify factors related to large pneumothorax, and propose a management algorithm for prevention, diagnosis, and treatment.

Methods

Included in this retrospective study were 118 patients who developed pneumothorax after receiving thoracic and lumbar tumor surgery between January 2015 and October 2021. A measurement of lung compression ≥20% on chest CT or x-ray was defined as large pneumothorax, and potential risk factors for large pneumothorax were identified by univariate analysis.

Results

Spinal tumor history and intraoperative blood loss were risk factors for large pneumothorax. The common symptoms of postoperative pneumothorax were chest pain, chest tightness and dyspnea. The mean longest transverse diameter of tumors was 6.63 ± 2.4 cm. En bloc resection was performed in 70 patients, with a mean operation time of 6.9 ± 2.5 h and mean intraoperative blood loss of 1771 ± 1387 ml. The most common pathologies were chondrosarcoma, giant cell tumors of bone, and neurogenic tumors.

Conclusion

During surgery, an artificial dura mater patch and a prolene suture can be used to repair the pleural and lung defects. We recommend chest CT as the preferred method for identifying postoperative pneumothorax. If a patient presents severe dyspnea, a large pneumothorax or concurrent pleural effusion, application of chest drainage is strongly recommended.

Association of Chest CT-Based Quantitative Measures of Muscle and Fat with Post-Lung Transplant Survival and Morbidity: A Single Institutional Retrospective Cohort Study in Korean Population

OBJECTIVE

Abnormal body composition is an important modifiable risk factor in lung transplantation. Therefore, precise quantification of different body components, including muscle and fat, may play an important role in optimizing outcomes in lung transplant patients. The purpose of the study was to investigate the prognostic significance of muscle and subcutaneous fat mass measured on chest CT with regard to lung transplantation survival and other post-transplant outcomes.

MATERIALS AND METHODS

The study population included 45 consecutive adult lung transplant recipients (mean age of 47.9 ± 12.1 years; 31 males and 14 females) between 2011 and 2017. Preoperative cross-sectional areas of muscle and subcutaneous fat were semi-automatically measured on axial CT images at the level of the 12th thoracic vertebra (T12). Additional normalized indexed parameters, adjusted for either height or weight, were obtained. Associations of quantitative parameters with survival and various other post-transplant outcomes were evaluated.

RESULTS

Of the 45 patients included in the present study, 10 mortalities were observed during the follow-up period. Patients with relative sarcopenia (RS) classified based on height-adjusted muscle area with a cut-off value of 28.07 cm²/m² demonstrated worse postoperative survival (log-rank test, p = 0.007; hazard ratio [HR], 6.39:1) despite being adjusted for age, sex, and body mass index (HR, 8.58:1; p = 0.022). Weight-adjusted parameters of muscle area were negatively correlated with duration of ventilator support (R = -0.54, p < 0.001) and intensive care unit (ICU) stay (R = -0.33, p = 0.021).

CONCLUSION

Patients with RS demonstrate worse survival after lung transplantation that those without RS. Additionally, quantitative parameters of muscles measured at the T12 level on chest CT were associated with the duration of post-lung transplant ventilator support and duration of stay in the ICU.

Oblique views of chest radiography from a designed rotation angle recommendation increase the contrast ratio between obscured lesions and surrounding structures

Background

Chest radiography (CXR) is the main tool used to detect pulmonary nodules. Lateral views of CXR are less effective and the aim of our study was to develop a rotation angle recommendation model to obtain the best oblique CXR with significantly increased contrast between lesions and surrounding normal structures in order to enhance the detection rate for potential obscured lesions on traditional posterior and anterior (PA) CXR.

Methods

A total of 140 subjects receiving low‐dose lung computed tomography (CT) screening were enrolled from the health check‐up database. An additional 14 cases with lung lesions on chest CT were included. Demography was also reviewed. Gross, left and right cardiothoracic ratios (CTR) were measured. All CT images were transformed to CXR to detect the best rotation angles and produce different views of CXR. Contrast ratio was calculated in the transformed CXR from CT with lesions. Comparison of contrast ratio among oblique, posterior‐anterior and lateral views was performed.

Results

CXR shows smaller gross CTR and left CTR but larger heart width and thoracic width in men than in women. Correlation evaluation displays gross CTR, heart width and left CTR are positively correlated with age only for the women group. The most important factor for the best rotation angle is right CTR for left rotation angle and left CTR for right rotation angle. The contrast ratio of the lesion to surrounding structures is significantly better on the oblique views in the designed angles than that on the traditional views.

Conclusion

CXR oblique views in the assigned angle from the 10‐degree rotation angle recommendation are able to enhance contrast ratio between the possible obscured lesions and surrounding structures on CXR.

Diagnosing Sarcopenia on Thoracic Computed Tomography: Quantitative Assessment of Skeletal Muscle Mass in Patients Undergoing Transcatheter Aortic Valve Replacement

RATIONALE AND OBJECTIVES

This study aims to assess the use of skeletal muscle mass measurements at two thoracic levels to diagnose sarcopenia on computed tomography (CT) chest examinations and to analyze the impact of these measurements on clinical outcome parameters following transcatheter aortic valve replacement.

MATERIALS AND METHODS

This study retrospectively included 157 patients who underwent preoperative CT examinations. The total muscle area was measured on transverse CT images at the 3rd lumbar and 7th and 12th thoracic levels with skeletal muscle indices (SMIs) calculated at each level. SMIs were then compared to clinical outcome parameters, and thoracic cutoff values for sarcopenia at the 7th and 12th thoracic levels were calculated.

RESULTS

Correlation between SMIs at the third lumbar vertebra (L3) and the 12th thoracic vertebra (T12) was stronger (r = 0.724, P < 0.001) than that between L3 and the seventh thoracic vertebra (T7) (r = 0.594, P < 0.001). SMIs at L3 and T12 significantly correlated with prolonged length of stay. Thoracic cutoff values for the 12th thoracic level were 42.6 cm²/m² (men) and 30.6 cm²/m² (women), and those for the 7th thoracic level were 46.5 cm²/m² (men) and 32.3 cm²/m² (women).

CONCLUSIONS

Skeletal muscle measurements at the T12 level could permit the diagnosis of sarcopenia and could be used to correlate sarcopenia with outcome parameters in patients undergoing CT limited to the chest.

The additional value of the lateral chest radiograph for the detection of small pulmonary nodules-a ROC analysis

OBJECTIVE

For the past 30 years, many authors have described different advantages of the use of the additional lateral chest radiograph. However, some radiologic departments gave up performing the lateral view recently. A potential reason for this might be a lack of evidence for any diagnostic benefit of the additional lateral view of the thorax in recent studies. The objective of this study was to evaluate the diagnostic benefit of the additional lateral view for the detection of small pulmonary nodules compared with CT examinations as a gold standard.

METHOD

The patient population consisted of 45 patients with SPN and 45 patients without SPN. Four radiologists with varying experience in the assessment of thoracic imaging first examined the sole posteroanterior (PA) projection. After a few days, they were instructed to examine the PA and the additional lateral view. A receiver-operating characteristic analysis was accomplished to compare the documented results.

RESULTS

The mean Az value of the sole PA view was 0.75 and 0.77 by the combination of PA and additional lateral view. So, there was no significant difference between the detectable Az values (Δ = 0.02; p = 0.384). With a cut-off value of >3, the additional view even reduced the sensitivity by averaging to 5.6%. The decrease of sensitivity by using the additional view was most detectable within the group of more experienced radiologists.

CONCLUSION

The additional lateral view of the chest provides no diagnostic benefit in the detection of small pulmonary nodules in comparison with the sole PA projection. Nevertheless, the results of the present study must not be understood as a general evaluation of the benefits of the lateral radiograph per se, because we did not examine other relevant issues (i.e. cardiac failure, lung parenchyma diseases or abnormalities in hilar anatomy). Advances in knowledge: Our study demonstrates a lack of evidence for any diagnostic benefit of the additional lateral view of the thorax in detecting SPN.

Imaging of invasive thymoma in the costophrenic recess presenting as thickening of arcuate ligaments of the diaphragm

Imaging findings in a patient with invasive thymoma in the costophrenic recess are presented, in whom computed tomography (CT) and MRI revealed lateral arcuate ligament thickening. Increased fluoro-deoxy-glucose (FDG) uptake on subsequent positron emission tomography (PET)/CT was helpful in suggesting the correct diagnosis. A second patient with much more obvious invasive thymoma occurring in the costophrenic recess is presented for comparison. It is a well-known fact that thymic malignancies can metastasize to the pleura even years after resection. Rarely, they may present as focal thickening of the diaphragmatic lateral arcuate ligament.