and Marco Rengo1
(1)
Department of Radiological Sciences, Oncology and Pathology, Sapienza University of Rome-Polo Pontino, Latina, Italy
(2)
Department of Radiology and Radiological Sciences, Medical University of South Carolina, Charleston, SC, USA
Fetal Circulation
It is supported by intra- and extracardiac shunts: ductus venosus (ductus of Aranzio), foramen ovale, ductus arteriosus.
Umbilical vein, usually single, providing oxygenated blood from the placenta to the heart of the fetus.
Umbilical arteries, usually two in number, originating from external iliac arteries.
Fibroelastoma, Papillary
Benign cardiac tumor attached to valve apparatus.
Rarely seen on MR due to the small size.
Differential diagnosis: vegetation or myxoma.
Fibroma
Benign ventricular cardiac tumor usually intramural.
Can cause mass effect.
MR: ipo- to isointense on T2 images.
Flail Leaflet
Usually results from a ruptured chordae or papillary muscle.
Severe regurgitation.
Flip Angle
Reduce FA to reduce SAR (i.e., children or pregnancy).
Attention: with SAR reduction also SNR is decreased.
Flow
General equation: ΔΦ = γ · Δm · v.
ΔΦ, phase difference; γ, gyromagnetic ratio; Δm, product of gradient area and time; v, velocity.
σ ~ velocity encoding/SNR.
Time resolution = 2 · TR · VPS.
Tips and tricks:
To increase SNR: increase thickness, flip angle, echo time, receiver bandwidth.
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