The objective of this study is to evaluate the image quality for different iodine delivery rates at different low voltage scanning protocols (80 or 100 kV ) under the modern advanced Multi-Detector Computed Tomography (MDCT) considering the body weight of patients.
The purpose of this study is to evaluate the image quality of different acquisition protocols in patients weighing less than 90 kg using low voltage 80 or 100 kV with a lower Iodine Delivery Rate based on the body weight of the patient, who will undertake coronary or craniocervical CTA (Computed Tomography Angiography) in routine procedures.
Study Type
OBSERVATIONAL
Enrollment
1,214
8 settings for CT Angiography as described in group description.
Unnamed facility
Multiple Locations, China
Contrast opacification of the target vascular segments, measured in Hounsfield Units (HU)
Defined as the CT value which can be measured on the CTA images.
Time frame: Up to 1 week
Value of CNR (contrast-noise ratio) of the vascular segments
Calculated by the formula: CNR = \[Averaged vascular segmental CT value - brain parenchyma (for carniocervical CTA) / perivascular tissues (for Coronary CTA (CCTA)) CT value\] / image noise
Time frame: Up to 1 week
Value of SNR (signal-noise ratio) of the vascular segments
Calculated by the formula: SNR = Averaged vascular segmental CT value / image noise
Time frame: Up to 1 week
Score of visual assessment of the CTA image quality
Subjective visual assessment using a 4-point scale: 1. Non-diagnostic 2. Adequate 3. Good 4. Excellent
Time frame: Up to 1 week
Score of diagnostic confidence of the CTA images
Subjective assessment of diagnostic confidence in the delineation of pathologic findings using a 4-point scale: 1. Insufficient 2. Adequate 3. Good 4. Excellent
Time frame: Up to 1 week
Injected dosage (ml) of the contrast media (CM)
Can be read from the screen of the CT injector.
Time frame: Up to 24 hours
Injection rate (ml/s) of the contrast media
Can be read from the screen of the CT injector.
Time frame: Up to 24 hours
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Value of the Idoine delivery rate (IDR) (unit: mg I/s)
Calculated by the formula: IDR (mg I/s) = CM concentration (mg I/ml) \* CM injection rate (ml/s)
Time frame: Up to 1 week
Value of the volume CT dose index (CTDIvol) (unit: mGy)
A parameter of the radiation dose which can be automatically generated and recorded by the CT machine.
Time frame: Up to 1 week
Value of the dose length product (DLP) (unit: mGy*cm)
A parameter of the radiation dose which can be automatically generated and recorded by the CT machine.
Time frame: Up to 1 week
Value of the effective dose (organ dose) (unit: mSv)
The effective radiation dose which can be estimated by DLP multiplied by a specific conversion coefficient.
Time frame: Up to 1 week
Heart rate of the patients who underwent CCTA before and after the CM injection
It can be read from the screen of the ECG monitor of the CT machine
Time frame: Up to 24 hours
Presence of injection pain or discomfort of the patients (Yes/No)
Assessed by investigators by asking patients if they have injection pain or discomfort.
Time frame: Up to 24 hours
Number of patients with adverse events / adverse drug reactions
Time frame: Up to 1 hour
Severity of injection pain or discomfort of the patients
Assessed by investigators by asking the patients of the severity (mild, moderate, severe) if present.
Time frame: Up to 24 hours