Difference In Strain Ratio Ultrasound Elastography Between Benign And Malignant Peripheral Parenchymal Lung Lesions.
Conditions: Peripheral Lung Lesions
Sponsor: Alexandria University

DIFFERENCE IN STRAIN ELASTOSONOGRAPGY BETWEEN 
BENIGN AND MALIGNANT PERIPHERAL PARENCHYMAL 
LUNG LESIONS  
Document date: 16th November 2022 
INTRODUCTION 
    Ultrasonography has been widely used for diagnosis since it was first 
introduced in clinical practice in the 1970s. For lung assessment, ultrasonography 
is not frequently used in medical practice.(1)  
Lung has long been thought to be an organ that cannot be examined by 
ultrasonography due to its high air content (>90%), which blocks the ultrasonic 
signal due to the large acoustic impedance differential between the superficial 
tissues of the chest.(2)   
In recent years, the use of lung ultrasonography has expanded beyond 
emergency situations to include routine examinations of patients with chronic lung 
illnesses. Lung ultrasonography has several benefits, including cheap cost, real-
time imaging, and the lack of radiation.(3) 
Elastography was developed in the 1990s to map tissue stiffness and 
reproduce/replace the palpation performed by clinicians. Two main types of 
elastography are currently in use, strain elastography where the tissue 
displacement in response to gentle pressure is used to compute and image tissue 

strain, and shear wave elastography where the speed of shear wave traversing 
tissue is measured and used to create an image of tissue stiffness.(4, 5) 
Elastosonography has been used to assess tissue stiffness and elasticity, 
particularly in liver, thyroid, breast, and prostate nodules suspected of cancer are 
currently investigable organs for non-invasive diagnostic imaging.(6, 7) 
 
The form, echogenicity, shadowing, and regularity of the margin are all factors 
to consider when assessing solid lesions with ultrasound. Thoracic ultrasound can 
also detect most of pleural pathologies e.g., effusion, pneumothorax, pneumonia, 
or bronchopneumonia consolidations in the subpleural zones, as well as local 
thickening (3 mm) of the pleural line.(8) 
 Lung ultrasound wave elastography (LUSWE) approach has the capability of 
assessing superficial lung tissue stiffness safely and swiftly with the objective of 
providing a noninvasive tool for evaluating lung elasticity.(9) 
The lung surface includes the space between the parenchyma and intercostal 
muscles; the surface wave speed on the lung is contributed by both the lung and 
the muscle.(10)  
Direct vibration stimulation on the lung surface is not achievable during lung 
testing. A vibration stimulation on the chest wall causes surface wave propagation 
on the lung.(11) 
An ultrasonic probe is used to detect the propagation of the tissue wave motion 
(usually a few micrometers). By indenting a medium and examining the 

relationship between the indentation displacement and the generated force, the 
indentation technique may determine the elasticity of that medium.(12) 
A local mechanical vibration on the chest safely generates the surface wave on 
the lung in LUSWE. Diagnostic ultrasonography is only utilized to identify the 
propagation of surface waves on the lung. Strain pictures are created by repeatedly 
applying modest pressure to the tissues using the transducers.(13, 14) 
Following tissue movement is tracked between pairs of echo frames, and 
strain is determined based on the axial gradient of the displacements. A stiff area  
 endures less strain (deformation) than surrounding softer tissue when subjected t
o the same amount of force.(9, 15) 
Most hospitalized patients are not able to perform radiological imaging either 
due to unavailability or inability to ambulate the patients for imaging to be held. 
We suggested to perform bedside, relatively cheap and available, imaging 
modality to help in the differentiation between benign and malignant peripheral 
lung pathologies.  
Lung elastography, to be used as diagnostic tool, is considered a new era 
worldwide; a new modality that will help to reduce the burden and the widespread 
use of chest computed tomography.(16) 
 
 
 

AIM OF THE WORK 
The aim of this study is to demonstrate the applicability and efficacy of strain 
elasto-sonographic measurements in differentiating between benign and malignant 
peripheral parenchymal lesions. 
 
 
 
 
 
 
 
 
 
 

PATIENTS 
This study will include patients recruited in cross-sectional sample till 
achieving requirement of 120 patients with benign and malignant subpleural 
parenchymal lesions. 
Sample size was calculated by medical research institute and biomedical 
informatics, Medical Statistics Department, Alexandria University.  
(APPENDIX A) 
Patients enrolled in our study will be examined and investigated in chest 
department, in Alexandria Main University Hospitals. 
Inclusion criteria: 
1) Adult patients above age of 18 years old. 
2) Patients with peripheral lung lesion. 
Exclusion criteria: 
1) Pure pleural lesions. 
2) Clinical instability to reach the final diagnosis. 
3) Inaccessibility by ultrasound. 
 

METHODS 
This is a diagnostic accuracy study with comparison to gold standard tests e.g., 
chest computed tomography, transthoracic biopsy, or microbiological analysis. All 
patients included in this study will give informed consent according to the 
guidelines 
of 
ethics 
committee, 
Alexandria 
Faculty 
of 
Medicine.  
(http://www.med.alexu.edu.eg/wp-content/uploads/2012/04/Checklist-FINAL-
20141.pdf-)                                  
Informed consent is available at (http://med.alexu.edu.eg/alexuniv/wp-
content/uploads/2021/09/Standard-Operating-Procedure-2020-ethics.pdf). 
All patients will be subjected to: 
1) Thorough history taking. 
2) Complete physical examination. 
3) CT scan chest. 
4) Routine laboratory investigation profile. 
5) Conventional methods to reach final diagnosis such as microbiological 
analysis, CT scan, fiberoptic bronchoscopy, and image guided biopsies. 
6) Strain elastography done by superficial and deep probes, in which B mode is 
compared with the elastography image for real time assessment; strain ratio is 
obtained. Strain ratio between benign and malignant peripheral lung lesions to 
be evaluated.  

Data collected from our research aim to estimate a cut-off value by which 
benign and malignant peripheral parenchymal lesions to be easily discriminated 
by ultrasonographic elastography. 
Statistical methods: 
Considering nominal data e.g., clinical features, CT findings, epidemiology, 
smoking status, and final diagnosis will be statistically analyzed using median, 
mode, MANN-WHITNEY, and Chi square tests.  
While numerical data analysis as arithmetic mean is helpful in situation of age 
statistical distribution. Strain ratio interpretation, the telltale sign of our study, is 
directed towards comparison of the cut off value achieved with the final diagnosis 
of the patients. 
 Receiver operator characteristic (ROC) curve will be plotted to evaluate and 
assess the sensitivity and specificity of strain ratio obtained from elastography 
compared to final diagnosis for 60 of our patients from the total 120 patients 
recruited in the study.  
While according to the remaining 60 patients, a multivariate Cox proportional 
hazard analysis would be held to validate and evaluate results obtained from the 
former 60 examined patients. 
 

At the end of the study, sensitivity, specificity, area under the curve (AUC), 
accuracy of a certain cut-off value, positive predicted value (PPV) and negative 
predicted value (NPV) would describe the performance of strain ratio as a 
diagnostic tool in the main aim of the research. 
 
 
 
 
 
 
 
 
 
 

ETHICS OF RESEARCH 
 
 
Research on human or human products:  
Prospective study: Informed consent will be taken from patients. In case 
incompetent patients, the informed consent will be taken from the guardians. 
Retrospective study: Confidentiality of records will be considered   
DNA / genomic material: Informed consent for DNA / genomic test and f
research will be taken from patients. No further tests will be carried out except w
further approval of committee and patients. If the samples will travel outside Egy
the researcher will be responsible for transportation and security approval.  
All drugs used in the research are approved by the Egyptian Ministry of Health
 
 
Research on animal:  
The animal species are appropriate for the test.  
After test, if the animal will suffer, it will be euthanized and properly disposed.
After operation, it will have a proper postoperative care.  
 
 سأقوم بتسليم الموافقات المبنية على علم المريض الخاصة بالدراسة عند االنتهاء منها او عند طلبها
من اللجنة 
√ 

RESULTS 
The results obtained from this study will be tabulated and statistically analyzed 
using appropriate statistical methods and appropriate figures and diagrams. 
 
 
 
 
 
 
 
 
 
 

DISCUSSION 
The results obtained from this study will be discussed in the view of 
achievement of the aim and will be compared with any of the available published 
data in the same field of the research. 
 
 
 
 
 
 
 
 
 
 

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APPENDIX A