Impact of Reconstruction Method (ASIR, FBP) Used in CT on Bone SPECT/CT Image Quality

Study Overview
=================
Brief Summary
-----------------
The main objective of this study is to demonstrate the non-inferiority of SPECT image quality (as measured by the signal / noise ratio) obtained by ASIR reconstruction of very-low-dose CT acquisitions versus the quality of those obtained by filtered back projection (FBP) of low-dose CT acquisitions. The lower limit of non-inferiority is set to -1, the average SPECT signal / noise ratio TEMP expected is between 5 and 6.

Detailed Description
-----------------
The secondary objectives of this study are: A. Demonstrate the non-inferiority of image quality (as assessed by a Likert scale) obtained by ASIR-reconstruction-SPECT versus FBP-reconstruction (the lower-limit of non-inferiority is set at -0.5); B. Verify the non-inferiority of image quality (as measured by the signal / noise ratio)of CT images obtained by ASIR-reconstruction versus FBP-reconstruction (the lower-limit of non-inferiority is set at -0.2); C. Verify the non-inferiority of image quality (as assessed by the Likert scale) of CT images obtained by ASIR-reconstruction versus FBP-reconstruction (the lower limit of non-inferiority is set at -0.5); D. Check that the irradiation dose received by the patient is lower for the acquisition of images reconstructed with ASIR than for the acquisition of images reconstructed with FBP. E. Check the concordance of two evaluations of image quality (Likert scale) made by nuclear medicine physicians (blinded to each other).

Official Title
-----------------
Impact of Reconstruction Method (Adaptive Statistical Iterative Reconstruction, Filtered Back Projection) Used in Computed Tomography on Bone Single-Photon- Emission-Computed-Tomography/Computed-Tomography Image Quality

Conditions
-----------------
SPECT-CT

Intervention / Treatment
-----------------
* Device: Asir Image Acquisition


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: The patient must have given his/her informed and signed consent The patient must be insured or beneficiary of a health insurance plan A SPECT-CT exam is scheduled for the patient The patient is able to withstand an extended position with the arms behind the head for 15 minutes (i.e. patient is able to undergo a SPECT-CT exam) Exclusion Criteria: The patient is participating in another study The patient is in an exclusion period determined by a previous study The patient is under judicial protection, or any kind of guardianship The patient refuses to sign the consent The patient has a contra-indication for a treatment necessary for this study (patient is not able to withstand an extended position with the arms behind the head for 15 minutes) It is impossible to correctly inform the patient The patient is pregnant, parturient, or breastfeeding Emergency situations Presence of osteosynthesis material (or any other material that would generate an artifact during SPECT-CT) in the spine Patient behaviour hampers image acquisition

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients undergoing SPECT-CT<br>The patients in this study are scheduled for a SPECT-CT at the Nîmes University Hospital as part of their normal care regimen. Intervention: Device: Asir Image Acquisition | Device: Asir Image Acquisition<br>* In addition to their normal image acquisition, a supplementary image acquisition lasting approximately 20 seconds (i.e. an ASIR image acquisition) will be carried out for each patient.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spect signal (kBq) | The Spect signal is measure on a 1 cm^3 zone of vertebrae L3. | 2 hours after inclusion (during SPECT-CT scan) | 
| Spect noise (kBq) | The spect noise is carried out on a 1 cm^3 zone of the aorta | 2 hours after inclusion (during SPECT-CT scan) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| CT signal (HU) | measured on a 1 cm^3 zone of the aorta | 2 hours after inclusion (during SPECT-CT scan) | 
| CT noise (HU) | measured on a 1 cm^3 zone of the aorta | 2 hours after inclusion (during SPECT-CT scan) | 
| Ratio of CT signal / CT noise |  | 2 hours after inclusion (during SPECT-CT scan) | 
| Spect image quality Likert scale ranging from 1 to 5, Evaluation n°1 |  | 2 hours after inclusion (during SPECT-CT scan) | 
| CT image quality Likert scale ranging from 1 to 5, Evaluation n°2 |  | 2 hours after inclusion (during SPECT-CT scan) | 
| Radiation dose (mSv) |  | 2 hours after inclusion (during SPECT-CT scan) | 
| Spect image quality Likert scale ranging from 1 to 5, Evaluation n°2 |  | 2 hours after inclusion (during SPECT-CT scan) | 
| CT image quality Likert scale ranging from 1 to 5, Evaluation n°1 |  | 2 hours after inclusion (during SPECT-CT scan) | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
ASIR, image acquisition, FBP