QUALITY ASSURANCE & ACR ACCREDITATION

West Physics Consulting is a proud supporter of MTMI’s Diagnostic Imaging Programs. Thank you West Physics!

WHY ACR ? Images property of Yu Liu PhD

WHY ACR ? Images property of Yu Liu PhD

IMAGE QUALITY Diagnostic Accuracy Signal to Noise (SNR) Contrast to Noise (CNR) Spatial Resolution Absence of Artifacts

SNR- Is the relationship between MR signal and background noise. Signal- Is the processing of induced voltage (Faraday’s Law of Induction) in a receiver coil after excitation. The voltage is dependent on the strength of the magnet (NMV) used for induction. Signal is not the only factor contributing to the quality of the image. Noise is refer as unavoidable background signals By evaluating SNR we can assess the overall quality of the MR Signal Images property of e-MRI.org

CONTRAST to NOISE RATIO (CNR) CNR: CNR: Also refers as Contrast Resolution,is the ability to distinguish between differences in intensity in an image. CNR is influence by the SNR and spatial resolution in the MR image.

Matrix (In-Plane) CONTRAST to NOISE (CNR) CNR : Is the ability to distinguished between two adjacent structures or tissue 192 x x 320

Slice Thickness CONTRAST to NOISE (CNR) CNR : Is the ability to distinguished between two adjacent structures or tissue 5mm 1.5mm

IMAGE QUALITY SNR/Spatial Resolution & Absence of Artifacts Scanner Performance

ACR (Q/A) Quaterly Preventive Maintenance Weekly Technologist Phantom – Phantom Scans Annual Testing by a Physicist – Phantom Scans – Coil Testing Re- Accreditation by the ACR – Every three years The MRI Accreditation Program evaluates the qualifications of personnel, the quality control program, MR safety policies and image quality specific to MRI.

ACR MRI ACCREDITATION Get the Team Together Get the Team Together – Radiologist (Medical Director MRI) – Chief Technologist (Clinical Imaging) – MR Physicist (Scanner Testing) Buy ACR Phantom Buy ACR Phantom (JM Specialty Part – San Diego,CA) Weekly Technologist Phantom Weekly Technologist Phantom (3-6 months ACR recommends) Scanner Testing by a Physicist Scanner Testing by a Physicist (Annual/Initial) Apply online for ACR Accreditation Apply online for ACR Accreditation (Select Module desire) – Survey Agreement (Site) – Six Modules (Brain,Spine,Msk,Body,Vascular,Cardiac ) – 45 days to complete your submission and return it to ACR – Could go back 6 months to provide clinical images. Getting Started:

ACR PHANTOM Images property of Chen Lin PhD Level Phantom Correctly

ACR PHANTOM ACR WEEKLY PROTOCOL : Sag Scout Sag Scout Ax T1 SE Ax T1 SE TR 500 TR 500 TE 20 TE 20 FOV 25 FOV 25 Matrix 256 x 256 Matrix 256 x 256 Slices 11 Slices 11 Slice Thickness 5mm Slice Thickness 5mm Gap 5mm Gap 5mm

ACR PHANTOM CENTER FREQUENCY: Set to the resonance frequency of water protons Set to the resonance frequency of water protons Depends on Main Magnetic Field (1.5T vs. 3T) Depends on Main Magnetic Field (1.5T vs. 3T) Affects fat saturations Affects fat saturations Severity off resonance artifacts Severity off resonance artifacts ACR recommended criteria < +/- 1.5ppm different between weekly test. Possible Causes of Failures : Phantom not Isocenter Phantom not Isocenter Magnet Drift Magnet Drift

ACR PHANTOM TRANSMITTER GAIN: RF power required to achived certain flip angles RF power required to achived certain flip angles Depends on RF Coils,Phantom,and Pulse Sequence Depends on RF Coils,Phantom,and Pulse Sequence Should remain constant Should remain constant Severity off resonance artifacts Severity off resonance artifacts. Possible Causes of Failures : Defective RF Transmitter Coil Defective RF Transmitter Coil RF Amplifier RF Amplifier

ACR PHANTOM ACR Sequence Positioning:

ACR PHANTOM Images property of Chen Lin PhD Geometric Accuracy: Related to image distortion 190 mm 148 mm

ACR PHANTOM. Possible Causes of Failures Phantom not level appropriate Phantom not level appropriate Gradient Non Linearity Gradient Non Linearity Eddy Currents Eddy Currents Geometric Accuracy: Related to image distortion ACR recommended criteria +/- 2mm in all directions

ACR PHANTOM SPATIAL RESOLUTION: Ability to detect differences between small structures Ability to detect differences between small structures Depends on Pixel/Voxel size (FOV/Matrix) Depends on Pixel/Voxel size (FOV/Matrix)

ACR PHANTOM. Possible Causes of Failures Poor SNR Poor SNR Bad Receiver Coil Bad Receiver Coil Eddy Currents Eddy Currents Gradient Calibration Gradient Calibration Spatial Resolution: ACR recommended criteria <= 1.0mm 1.1 mm 1.0mm 0.9mm

ACR PHANTOM Low Contrast Detectability (LCD): Ability to detect objects with subtle differences in signal intensity Ability to detect objects with subtle differences in signal intensity Possible Causes of Failures Poor SNR Poor SNR Inaccurate slice positioning Inaccurate slice positioning Artifacts Artifacts

ACR PHANTOM Additional Testing: Image uniformity Image uniformity Slice Thickness Slice Thickness Ghosting/Artifacts Ghosting/Artifacts

ACR PHANTOM Artifacts: Zipper/RF Leak

ACR ACCREDITATION Clinical Modules: Images property of Chen Lin PhD

ACR ACCREDITATION Clinical Images Evaluations : Pulse Sequence Pulse Sequence Image Contrast Image Contrast Anatomical Coverage Anatomical Coverage Imaging Planes Imaging Planes Spatial Resolution (Pixel & Voxel size) Spatial Resolution (Pixel & Voxel size) Artifacts Artifacts ID Exam ID Exam

ACR ACCREDITATION Tips & Suggestions All clinical images must be done in patients (No Volunteer). All clinical images must be done in patients (No Volunteer). Include all identification required (Patient & Parameters). Include all identification required (Patient & Parameters). DICOM images with a viewer. DICOM images with a viewer. Except Cardiac and Phantom DICOM only Except Cardiac and Phantom DICOM only Record True Matrix,not Reconstructed Matrix (Pixel size). Record True Matrix,not Reconstructed Matrix (Pixel size). Check for Artifacts prior to submission. Check for Artifacts prior to submission. Present best cases,no motion on images. Present best cases,no motion on images. Submit all required sequences,include localizers. Submit all required sequences,include localizers.

ACR ACCREDITATION Be Aware : Spine Axial GRE T2*/TSE at 3T,CSF must be bright(no flow artifact) Spine Axial GRE T2*/TSE at 3T,CSF must be bright(no flow artifact) MRCP include entire Biliary Tree Anatomy (Best when using 3D rather 2D MRCP) MRCP include entire Biliary Tree Anatomy (Best when using 3D rather 2D MRCP) Liver MRI,use flouro technique to acquired true arterial phase. Liver MRI,use flouro technique to acquired true arterial phase. CE-MRA,no venous contamination (Neck Carotid) CE-MRA,no venous contamination (Neck Carotid) Cardiac MRI,Viability exam myocardium fully saturated (Scar visible) Cardiac MRI,Viability exam myocardium fully saturated (Scar visible) Considered using Dixon for In/Out Phase at 3T Considered using Dixon for In/Out Phase at 3T Forms fill them out correctly(take your time) Forms fill them out correctly(take your time)

ACR ACCREDITATION Breast Accreditation: Breast Accreditation: Facilities performing breast MRI must have the capacity to perform mammographic correlation, directed breast ultrasound, and MRI-guided intervention, or create a referral arrangement with a cooperating facility that could provide these services. Radiologists – Requirement of Breast MRI read in the last 36 months Facilities must use the Breast Imaging Reporting and Data System (BI- RADS®)7 final assessment codes and terminology for reporting and tracking outcomes. Technologists – Requirement of 50 MRI Breast examination prior 24 months.

ACR ACCREDITATION Breast Accreditation: Facility must submit 1 case with a known, enhancing, biopsy- proven carcinoma clearly visible in the breast parenchyma. No Masectomy cases Pulse Sequences T2W/Bright Fluid T1W (Pre,Arterial,Delay) - Bilateral Slice Thickness < 3mm(No Gap),In Plane Resolution/Pixel Size < 1.0

ACR ACCREDITATION Summary: ACR Q/A Phantom needs to be done weekly Check scanner image quality Yearly Evaluation (PhD) Compares year to year scanner performance ACR Accreditation Done every three years,includes clinical images and phantoms. Why ACR ? Is all about image quality!!!!!! Is all about image quality!!!!!!