CT angiography and MRI of hand vascular lesions: technical considerations and spectrum of imaging findings

Insights into Imaging

Table 2 Protocols for CTA of the hand

Scan protocols	Classic helical CTA	Dynamic CTA	Helical CTA with SHR
Precautions before scanning	Avoid cold and smoking; warm the hand; exercise by squeezing a ball
Hand position	Prone position, hand as close as possible to the centre of the gantry
Acquisition direction	Cranial–caudal	Not applicable	Cranial–caudal
Number of acquisitions after ICM injection	2	8–12	2
Delay between each acquisition	12 s	5 s	15 s
Scanning range	20–25 cm	4–16 cm	20–25 cm
Detector coverage and slice thickness	80 × 0.5 mm	80–320 × 0.5 mm	160 × 0.25 mm
Pitch	Detail (0.637)	0	Detail (0.569)
Scanning time for each acquisition	10 s	0.5 s	13.5 s
Scanning FOV	Ideally < 12 cm	Ideally < 12 cm	Ideally < 12 cm
Focal spot	Small	Small	Ultra-small
Matrix size	512 × 512	512 × 512	1024 × 1024
kVp	100	80	100
mAs	70–130	75	100–200
Rotation time	0.5 s	0.5 s	1 s
CM amount	1.2–1.3 ml/kg body weight
Saline flush	30 ml
Flow rate	4–5 ml/sec
Arterial scanning delay	Manual bolus tracking	Test bolus or manual bolus tracking	Manual bolus tracking
Reconstruction algorithms	Iterative or DLR reconstruction with standard and high-resolution kernels
Post-processing	MPR, MIP, GI, bone subtraction