Complexity Can Introduce Unintended Variations
Unintentional variations in the image acquisition process can impact your ability to generate reproducible results and achieve a consistent standard of quality patient care.
Analysis of Radiation Dose Distribution by Hospital
In a large study (STONE), one of the variables measured and published in a separate letter1 was the CT radiation dose in kidney stone exams. A wide range of practices and radiation doses administered to patients was recorded from 15 hospitals and 1,582 patients over 17 months.
Study Design: Data from the STONE study was later analysed in a separate publication1. Patients were eligible if the emergency physician suspected urolithiasis and were excluded if they were obese or at high risk for a significant alternative diagnosis.
- 200x variation in dose between patients.
- 5x variation in median doses between hospitals (4-19 mSv)
- 8% of patients received a low-dose scan of recommended 4 mSv or less
How do you address unintentional variations in your image acquisition process?
Dose Variation Among Patients
Basel University Hospital reduced the median dose for CT thorax exams by 67% (Mean DLP 245 to 81 mGy-cm). Using RadimetricsTM, dose variability between scans was also reduced between the 25 and 75 percentiles. This allows University Hospital Basel to perform CT Thorax exams at a median DLP 80% below the national Dose Reference Level.*2
When Reproducible Quality is Your Goal, Be Confident with Seamlessly Smart Consistency
The RadimetricsTM Enterprise Platform, together with point of care applications,*** offers a set of management tools.
Improved Reproducibility Through Protocol Optimisation. Your enterprise protocol library may contain a selection of outdated, suboptimal, or redundant scan protocols across your scanner fleet.
Inconsistent and unpredictable dose effects can occur if protocol availability and selection at the individual scanner is unmanaged. Image acquisition that generates consistent results may help optimise scans, which translates into better quality care for your patients.
The RadimetricsTM Enterprise Platform protocol management can help your department harmonise its protocol library to reduce variability.
Redundancies and obsolete instances can be eliminated when device libraries are mapped to a standard catalogue. You can also promote consistent use by standardising protocol names across all devices. In addition, the dose management software allows you to track dosing from each CT examination and calculate the average dose for each CT protocol. This helps you select the most dose-effective protocols.
Training Helps Achieve Consistent Scanner Operation
Advances in technology, coupled against a backdrop of budgetary limitations, contribute to an imaging environment that is increasingly challenging.
Technological complexity and scanner diversity can contribute to undesirable variations such as differences in radiation dose and image quality between users and shifts.
For example, even subtle changes like table height may impact the results obtained from the automated scanner algorithms. Beyond scanner parameter settings, scan range selection also impacts the total dose delivered.
The RadimetricsTM Enterprise Platform features interactive modelling capabilities. This functionality allows users to review simulated scenarios and visualise resulting organ doses. Further, the visualisation of tube current modulation facilitates the detection of an unintentional selection of scan parameters.
Prevent Contrast Variations To Help Improve Image Quality
Because contrast enhanced exams are among the more complex acquisitions, correct volume, concentration and timing need to be controlled.
With suboptimal settings, exams may exhibit suboptimal image quality. Rescans effectively double the patient dose.
Our CT point of care applications** for contrast media injections allow you to monitor and adjust volume, concentration, and timing. Contrast algorithms for consistent enhancement are available for:
- Imaging of abdominal organs such as liver, pancreas, kidneys (P3TTM Abdomen)
- CTA studies of the main and segmental pulmonary arteries to assess for pulmonary embolism (P3TTM PA)
- CTA imaging of cardiac structures (P3TTM Cardiac)
Reproducible Quality: Perform Acquisitions with Consistent Results
Personalised Patient Protocol Technology (P3T)
The role of CT angiography (CTA) has been well established in the detection of pulmonary thromboembolism. Optimising contrast injection and scanning parameters has become of increased importance with the faster multidetector scanners to achieve diagnostic quality images. The purpose is to assess if a prototype automated software program for patient specific contrast injection, P3T Cardiac, is comparable to or offers advantages over site specific standard protocol used for chest CTA.3
Table 1. Comparison of PA Enhancement, Deible et al: A clinical evaluation of an automated software program (P3T PA) for patient specific contrast injection during chest CTA to exclude pulmonary embolism.
RadimetricsTM: A Firm Foundation for Personalised Care
Once consistency has been achieved you have a firm foundation on which to personalise the exam regarding correct dosing and scanner choice.
The referring physician or radiologist should consider patient needs based on age, habits, and scan history. The indication and accumulated dose from prior exams may influence imaging decisions such as what modality to use (ionising vs non-ionising) and what scanner to choose (conventional vs low dose). Contrast dose should be personalised based on patient weight and other exam factors.
The Dose Engine accurately determines radiation dose for the patient and 26 organs. Non-ionising modalities may be considered if critical dose levels are approached over a certain time frame for:
- Young patients
- Dose sensitive organs (breast, ovaries, eye lens)
- Frequently scanned patients
RadimetricsTM allows users to easily compare average dose levels per scanner for a given protocol, which can differ by 4 fold4. In sites with a heterogeneous scanner fleet, this helps triage patient sub-populations between low-dose and conventional or older machines.
Cumulative Dose Measure of a Single Patient 4
Adapted from figure 3, The dose page of a patient who had a pancreatitis with multiple complications. The patient received 14 CT scans within 6 months and built up a cumulative radiation dose of almost 170mSv.
"We came to the conclusion that some of those CT scans could have been replaced by an MRI or an Ultrasound without impacting patient management. Based on this incident, we set a cumulative effective dose of 100mSv."4
Sebastian T. Schindera,
MD Clinic of Radiology and Nuclear Medicine University of Basel Hospital, Switzerland
Consistent Contrast Enhancement
Personalised protocol technology automatically adjust contrast media protocols to allow for differences in patient body weight, contrast concentration, total iodine load and a series of other configurable factors to improve image quality and manage within the specific hospital’s contrast protocolling guidelines. It allows for consistent contrast enhancement, even in complex studies and across a wide range of patients.
* The results cited represent the outcomes achieved by the respective institution and are not necessarily representative of every site. Results will vary based on a site’s existing circumstances and the quality of the improvement programs adopted by the site.
** Requires CertegraTM Workstation 3.0 for Medrad®Stellant with P3TTM application.
*** Point of care software applications available on Medrad® Stellant® with Workstation 3.0, Medrad®Stellant® FLEX, Medrad® MRXperion or Medrad® Centargo.
1 Smith-Bindman R, Moghadassi M, Griffey RT, Camargo C, Bailitz J, Beland M, Miglioretti D, Computed Tomography Radiation Dose in Patients With Suspected Urolithiasis. JAMA Intern Med. 2015;175 (8):1413- 16.
2 Parakh A, Kortesniemi M, Schindera S, CT Radiation Dose Management: A Comprehensive Optimisation Process for Improving Patient Safety. Radiology. 2016;280 (3):663-73.
3 Deible et al: A clinical evaluation of an automated software program (P3TTM PA) for patient specific contrast injection during chest CTA to exclude pulmonary embolism. Bayer Healthcare, November 2014 (RAD-INF-14-06087).
4 Schindera S, Practical lessons on Improving Safety, Reproducibility and Efficiency Using a Dose Management Software, University of Basel Case Study (G.RI.11.2014.0325)