Idea Transcript
Radiology Insights
A Clinical Evaluation of an Automated Software Program (Certegra™ P3T PA) for Patient Specific Contrast Injection During Chest CTA to Exclude Pulmonary Embolism Christopher R Deible MD, PHD a Jacob Alexander MD a Iclal Ocak MD a Maryam Ghadimi Mahani MD a John Kalafut BS, MS b Janet E Durick MD a Carl R Fuhrman MD a Darlene Frasher RN, MSN a Karen M Pealer BA, CCRC a Michael P. Federle MD a Joan M Lacomis MD a
>> Introduction Optimizing contrast injection and
Introduction
BMI 17.5 HR 96 bmp CO ~4.25 L/min Contrast volume: 78 cc
scanning parameters has become of increased importance with the faster
The role of CT angiography (CTA) has
pose of our study is to assess if a pro-
multidetector scanners to achieve
been well established in the detection of
totype* automated software program
diagnostic quality images.2-6
pulmonary thromboembolism. Accord-
for patient specific contrast injection,
ing to the PIOPED II study, CTA overall
Certegra™ P3T PA (Pulmonary Angiogra-
sensitivity and specificity is 83% and
phy), Bayer, Pittsburgh, PA, is comparable
96% respectively.1, 2 Optimizing contrast
to or offers advantages over our site spe-
injection and scanning parameters has
cific standard protocol used for chest CTA
become of increased importance with the
to exclude pulmonary embolism (PE).
faster multidetector scanners to achieve
>> Estimated cardiac output was computed using standard look-up tables
BMI 24.9 HR 100 bpm CO ~6.2 L/min Contrast volume: 84 cc
diagnostic quality images.2-6 The pur-
Methods and Materials 62 emergency department patients re-
CTA Certegra™ P3T PA Group
ferred for chest CTA to exclude PE under-
As a safety measure, a default max which
went informed consent for this study and
allowed injection rate of 6cc/sec was pre-
were randomized to Certegra™ P3T PA
selected. Height, weight, age, sex, heart
versus Standard (control) groups. All
rate and scan duration were entered into
had 18 gauge IV access, received the
Certegra™ P3T PA which generated test
contrast agent Ioversol (350mg/ml io-
bolus parameters. From the test bolus,
dine; Mallinckrodt, St Louis, MO) and
time to peak and peak density (HU) in the
were scanned on one 64 slice CT scan-
MPA were entered into Certegra™ P3T PA
ner (VCT, GE Healthcare; Milwaukee, WI)
which generated scan bolus and scan de-
by selected technologists monitored by
lay parameters.
BMI: 20.5 HR: 89 bpm CO ~7.12 L/min Contrast volume: 87 cc
selected investigators (JL, CD, JA). Scan parameters: 0.625 mm collimation; 0.24
Data Collection/Analysis
pitch; 9.6 mm/sec table speed; 350 msec
Two readers, blinded to injection method,
rotation time; 120 kV; 280 - 550 mAs.
jointly measured density (HU) of main
Recorded patient parameters: height,
(MPA, RPA, LPA) and segmental pulmo-
weight, age, sex and heart rate.
nary arteries (bilateral upper and lower lobes), and SVC. Three other blinded read-
* Evaluation was performed on prototype and software has been released for commercial use post evaluation.
2
CTA Standard Group
ers qualitatively scored scans compared
Test bolus = 20cc contrast/ 50cc saline
to an “adequate” example for image qual-
flush @ 4cc/sec to time for main pul-
ity to assess for PE, noting limitations:
monary artery (MPA). Scan delay = time
poor contrast, motion, quantum mottle,
to contrast peak MPA + 9 seconds. Scan
SVC streak and artifact. The mean and
bolus = 80cc contrast/ 50cc saline flush
standard deviation for each group was
@ 4cc/sec.
calculated separately. Statistical analysis
Figure 1 Certegra™ P3T PA Scans
was performed with the Student’s t-test, and the Wilcoxon rank sum test.
3
>> Results Higher percentage of exams ranked as
Results
Certegra™ P3T PA Weight: 300 pound Contrast: 116 cc Main PA HU: 274
diagnostic without limitation (positive or negative for PE) in the Certegra™ P3T
¡ Certegra™ P3T PA population: 20 women, 11 men
PA exams (100%) vs. Standard exams
– Age: mean 43.7 yrs (range: 20 – 76)
(73%*) (p > Contrast enhancement of pulmonary arteries in Certegra™ P3T PA exams vs Standard exams (p