Evaluation of the Influence of Ultrasound Probe Pressure on the Intratendon Doppler Signal in Patellar Tendinopathy
Phase: NA
Conditions: Patellar Tendinitis
Sponsor: Cardenal Herrera University

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
GENERAL STUDY INFORMATION AND INFORMED CONSENT 
 
UNIVERSITY CEU CARDENAL HERRERA  
 
Principal investigator: Dr. Sergio Montero Navarro 
 
TITLE: Ultrasound Probe Pressure on the Intratendon Doppler Signal in Patellar 
Tendinopathy 
 
Research and Ethics Committee of CEU Cardenal Herrera University Number: CEI20/073 
 
NCT ID:  
DATE: 12-09-2020 
 
 
 

 
 
CONSENT DOCUMENT FOR PARTICIPATION IN A RESEARCH 
PROJECT  
  
EVALUATION OF THE INFLUENCE OF 
ULTRASOUND PROBE PRESSURE ON THE INTRATENDRON DOPPLER SIGNAL 
ON PATELLAR TENDINOPATHY   
 
Principal investigator: Dr. Sergio Montero Navarro   
  
NAME:_______________________________________________________  
ID No.____________________  
Freely and voluntarily  
  
Manifest:  
1. I have read and understood the fact sheet under study.   
2. I have had the opportunity to ask questions.   
3. My questions have been answered satisfactorily.   
4. I have received sufficient information from the study and the tests to be performed.   
5. I understand that participation is voluntary and I can leave the study at any time without 
explanation and without affecting my medical care.   
6. In accordance with Regulation (EU) 2016/679 of the European Parliament and of the 
Council of 27 April 2016 on the protection of natural persons with regard to the processing 
of personal data and on the free movement of such data and repealing Directive 
95/46/EC, I have been informed that my personal data, obtained by completing this form 
as well as those resulting from my participation in the project will be processed under the 
responsibility of the UNIVERSITY FUNDATION SAN PABLO CEU (hereinafter, FUSP-
CEU), in order to manage my participation in this research project. In addition, I have 
been informed of the following aspects:   
a. Profiling is planned to analyse or predict aspects of my health.   
b. That the treatments indicated are legitimized in the consent granted by me.   
c. That my personal data, obtained by completing this form, as well as those 
resulting from my participation in the project will be kept for the time necessary 
for the development of this research, which is estimated to be1 1 months, being 
subsequently destroyed, without being preserved without having previously been 
anonymized. In any case, they may not be transferred without my express 
consent and I do not grant it in this act.   
d. That I can contact the Data Protection Officer of FUSP-CEU, directing my 
written request to the postal address C/ Tutor no. 35 - 28008 Madrid or to the 
email address dpd@ceu.es. 
e. That in accordance with the rights conferred on me by the current legislation 
on data protection I may contact the competent Supervisory Authority to submit 
the complaint that it deems appropriate, as well as I may exercise the rights of 
access, rectification, limitation of processing, deletion, portability and opposition 
to the processing of my personal data and withdraw the consent given for the 
processing thereof, directing my request to the responsible investigator at the 
contact address contained in this document.   
7. I agree that my written consent and other data are available to the clinical research 
project in which I am participating, and the researcher responsible for it, Sergio 
Montero Navarro, but always respecting the confidentiality and assurance that my data 
will not be publicly available in a way that can be identified.  
8. The data collected for this study will be included, with those of other persons 
participating in this study, in a personal database of the CEU Cardenal Herrera 
University, to which only the researchers approved for this project will have access, all of 

 
them being subject to the secret inherent in their profession or derived from a 
confidentiality agreement.  
9. I voluntarily sign this information and consent document to express my desire to 
participate 
in 
this 
research 
study on the 
assessment 
of 
the 
influence 
of ultrasound probe pressure on the 
intratendon Doppler signal 
on patellar 
tendinopathy, until I decide, otherwise. By signing this consent, I do not renounce any of 
my rights. I will receive a copy of this document to save it for future reference.   
I therefore consent and consent to the detailed study with the help of the necessary staff with 
due qualification and specialization.  
 
The participant   
(Signature) Name, Last Name   
 
 
  
                Elche, a ......... ..................... 20....   
  
  
FAMILY OR TUTOR AUTHORIZATION  
In the face of the impossibility of ________________________________________ 
with ID___________ to provide authorization for the treatments expressed in this document 
freely, voluntarily, and consciously.   
NAME:____________________________________________   
with ID__________________________________ 
As a (husband, wife, child, brother, legal guardian, family member, close friends, 
caregiver), I decide, within the available clinical options, to give my free, voluntary and 
conscious consent to the technique described for the treatments set out herein.  
  
ELCHE,  of _______________________of____________   
  
Researcher  
Dr. SERGIO MONTERO NAVARRO   
ID: 74372902X   
Email: sergio.montero@uchceu.es   
Phone: (34) 96 542 64 86 ext. 67704   
 
Researcher at the CEU-Cardenal Herrera University of Valencia, I declare that I have 
provided the study participant and/or authorized person with all the information 
necessary for the realization of the intervention explained in this document and declare 
that I have confirmed, immediately prior to the application of the technique, that the 
participant does not incur any of the contraindication cases related above, as well as 
having taken all the necessary precautions for the correct intervention.  
  
Elche,_____of _______________________of____________   
  
REVOCATION OF INFORMED CONSENT  
NAME:____________________________________________  
with ID:_______________________________________ 
I revoke the consent given on the date of__________________________    
And I do not wish to continue the treatment I give on this date.  
  
______________, _____de _______________________de____________  
  
 

 
 
PARTICIPANT INFORMATION  
  
STUDY TITLE: 
EVALUATION OF THE INFLUENCE OF ULTRASOUND PROBE 
PRESSURE ON THE INTRATENDRON DOPPLER SIGNAL ON 
PATELLAR TENDINOPATHY. 
 
PRINCIPAL INVESTIGATOR: Dr. Sergio Montero Navarro.   
  
1) Information to the participant of the study object:   
 
An ultrasound scan will be performed in Doppler mode on the patellar 
tendon. The scan will be performed with different pressures on the, simulating the 
pressure that a clinician can perform during ultrasound examination. To generate the 
different pressures,, an articulated arm with a force meter to which the probe is attached 
will 
be 
used. Ultrasound 
videos (Doppler) of 
each 
pressure 
exerted will 
be 
recorded. After that, they will be stored for further image analysis. This procedure is 
safe, painless and may take about 15 minutes.   
 
The objective of this study is to evaluate the influence of ultrasound tube pressure 
that the clinician may exert during the patellar tendon scan on the signal image of the 
vessels inside the affected tendon.   
 
This study was approved by the Research and Ethics Committee of CEU 
Cardenal Herrera University (CEI20/073) 
  
2) Protection of personal data:   
 
In accordance with Regulation (EU) 2016/679 of the European Parliament and of 
the Council of 27 April 2016 on the protection of natural persons with regard to the 
processing of personal data and on the free movement of such data and repealing 
Directive 95/46/EC, I have been informed that my personal data, obtained by completing 
this form as well as those resulting from my participation in the project will be processed 
under the responsibility of the UNIVERSITY FUNDATION SAN PABLO CEU 
(hereinafter, FUSP-CEU), in order to manage my participation in this research project.  
  
Name and surname of the researcher:   
 
Dr. Sergio Montero Navarro  
ID: 74372902X:   
Postal address of contact of the Investigator: Plaza Reyes Católicos, 19. 03204 Elche 
(Alicante)  
E-mail: sergio.montero@uchceu.es  
Phone: (34) 96 542 64 86 ext. 67704 / 651472265  
 

 
 
 
 
 
 
 
 
 
 
 
 
 
STUDY PROTOCOL PLAN AND STADISTICAL ANALYSIS PLAN (SAP)  
 
UNIVERSITY CEU CARDENAL HERRERA  
 
Principal investigator: Dr. Sergio Montero Navarro 
 
TITLE: Ultrasound Probe Pressure on the Intratendon Doppler Signal in Patellar 
Tendinopathy 
 
Research and Ethics Committee of CEU Cardenal Herrera University Number: CEI20/073 
 
NCT ID:  
DATE: 12-09-2020 
 
 
 
 

 
STUDY PROTOCOL PLAN 
 
Objectives: 
 
The objectives of our study have been the following: 
 
- 
Analyze the influence of the pressure exerted on the probe on the variables of 
area, number of signals, pixel intensity, perimeter, solidity, perfusion index, 
circularity, major and minor diameter of the intratendon Doppler signal in the 
evaluation of patellar tendinopathy. 
 
- 
To study the relationship between the pressure exerted on the probe and 
intratendon perfusion in the Doppler evaluation of patellar tendinopathy. 
 
Volunteers who want to participate in the study will read the general information of the 
study and sign the informed consent to participate in the study. 
 
Once the informed consent has been read and delivered, the evaluator will check that 
they meet the inclusion criteria. 
 
A quasi-experimental study of a single group will be carried out, consisting of subjects 
with patellar tendinopathy with intratendon hyper vascularization. Intratendon 
vascularization will be quantified using a proprietary methodology using ImageJ 1.47v 
image analysis software, determining the different variables related to the Doppler signal 
within an intratendon region of interest. 
The first contact with the patient likely to participate in the project will always be made 
by the same researcher who will duly inform them of the study and provide informed 
consent in case of accepting participation for the performance of the exploratory 
ultrasound. Subsequently, a general questionnaire will be completed, where 
sociodemographic data and other data referring to the injury and sports practice are 
collected, also adding the VISA-P questionnaire that assesses the symptomatic severity, 
the severity of the symptoms and the capacity functional function in patients with patellar 
tendinopathy. Lastly, the ultrasound examination will be carried out in power-Doppler 
mode. 
 
 The ultrasound examination will begin with the positioning of the patient on the table in 

 
the supine position and with both knees extended. At the level of the knee to be explored, 
a support with an articulated arm will be placed where the probe attached to the force 
meter will be fixed. After positioning the articulated arm, a power-Doppler ultrasound 
scan of the intratratendon vascularization will be carried out, making longitudinal cuts of 
the patellar tendon and using previously pre-established Doppler optimization 
parameters for all patients. The optimization parameters of the power-Doppler signal will 
be set at a Doppler frequency of 6.7 MHz, pulse repetition frequency (PRF) of 0.7 kHz. 
The lowest wall filter and a standardized gain just below the level that produces random 
noise will be applied. 
This examination will be repeated several times with different probe pressures, which will 
be quantitatively adjusted through the force sensor and maintained with the articulated 
arm. A 4-second static video will be recorded of the longitudinal section that presents a 
higher Doppler signal in each of the scans at different probe pressures. 
These videos will be saved for later analysis with ImageJ 1.47v software (Wayne 
Rasband, National Institutes of Health, USA, 2012) to determine and quantify the 
presence of intratendon Doppler signal. 
The processing and analysis of the videos and images will be carried out on the image 
with the highest and lowest Doppler signal of each stored video. Once the image has 
been scaled, a region of interest (ROI) with dimensions capable of encompassing the 
intratendon Doppler signal will be selected individually. 
To quantify the Doppler signal, the saved image with the highest Doppler signal of each 
video was selected and the area of color pixels was calculated. 
 
To quantify the flux, the pixel color mean of the Doppler signals of each image was 
calculated. The mean pixel color of the image with the highest signal was considered as 
data of the maximum systolic velocity, and the one with the lowest signal as the final 
diastolic velocity. These data were transferred to the IR formula, obtaining a value 
associated with the intratendinous flow pattern (perfusion index). 
 
In the images that did not detect a Doppler signal, or did not present an intratendon 
Doppler signal in diastole, the IR was determined as 1, which represents normality in the 
musculoskeletal tissue. 
 
In addition, the parameters of number of signals, mean intensity of the pixel, area, 

 
perimeter, major and minor diameter, circularity and solidity were automatically 
calculated on the selected images with the highest Doppler signal of each recording. 
 
This methodology will be carried out following the previously established and 
standardized order, based on standardized protocols for both subject positioning and 
echo-Doppler exploration. The ultrasound examination and subsequent analysis of the 
images will be described exactly and precisely so that they can be easily reproducible. 
All data obtained will be recorded in a computer spreadsheet to make the final statistical 
analysis easier and to obtain a greater and faster interpretation of the results. 
 
 
 

 
Statistical Analysis Plan (SAP) 
 
First, all the variables of interest will be detected and later they will be coded, labeled 
and transferred to a database. A data collection notebook (CDN) will be created where 
the variables, their reference values, measurement system and interpretation will be 
described and which will be available to all members of the working group. The programs 
used will be Microsoft © Access and Excel for initial data registration and IBM SPSS 
Statistics 19.0 for analysis. 
 
Data debugging and control systems 
 
The data related to the clinical information of the subjects and related to the 
questionnaires will be recorded in a database created for this purpose (Microsoft Access 
©) with data entry protection systems. The same researcher will always record the data 
and a feedback review will be carried out for the detection of errors and lost cases by a 
third person. Missing and out-of-range screening will be performed. 
 
The data related to the variables obtained by image analysis of ultrasounds will be 
exported in an automated way with a macro created for this purpose from the data 
analysis program in ASCII format to avoid incompatibilities between the image analysis 
program and the imaging programs. statistical analysis. 
 
Exploratory Data Analysis (EDA) 
 
 Qualitative variables will be summarized in the form of counts and relative frequencies 
and, where appropriate, absolute frequencies and their confidence intervals (95% CI). 
Graphic summaries will be made using bar diagrams. 
 
The quantitative variables will be summarized by means, standard deviations, medians, 
and interquartile ranges. Confidence intervals will also be provided for each of the 
measures. Graphical summaries will be made using box plots and bar diagrams with 
95% CI. 
 
A univariate analysis of outliers will be carried out and their influence will be verified 
through the Z scores. Multivariate analysis of atypical cases and their influence will be 
carried out using the Mahalanobis distance. 
 
Unusual cases will be removed from the analysis only if it is certain that they are wrong. 
 
It will be checked whether the quantitative variables of interest follow a normal 
distribution (Kolmogorov-Smirnof test). The normality tests will be accompanied by the 
Q-Q normality graphs with and without trend that will aid interpretation and decision-
making. In the event that any of the variables of interest does not conform to a normal 
distribution, a transformation of this will be carried out until it is achieved as long as its 
interpretation is not compromised. 
 
Analysis of data 
 
In the case of fulfilling the assumption of normality, parametric tests will be chosen and 
if not, the non-parametric alternatives will be chosen. 
 
The measurement pattern used will be randomized, all subjects will be assigned to a 
minimum or a maximum probe pressure as the start of the measurements. The 
randomization factor (pressure) is included as a fixed effect, which will prevent a possible 

 
interaction between pressure and the quantification of the Doppler signal. 
 
To perform the statistical analysis, in the case that the variables present normality, the 
Pearson correlation coefficient will be used for quantitative variables. In order to better 
visualize the joint behaviour of both variables, scatter diagrams will be added and to 
determine the effect size and interpret the degree of shared variance, the coefficient of 
determination will be calculated. In the event that any variable does not present 
normality, the Spearman Rho correlation test will be chosen.