I/V contrast is not used in –
IV contrast agent is given in :-


X-ray based investigation (Radiocontrast agent) :- Radiography (simple x-ray), CT-Scan.
MRI (MR contrast agents).
Ultrasound (USG contrast agents).


IVP (intravenous pyelography) as the name suggests, the contrast agent is given intravenously.
In myelography, the contrast agent is injected into subarachnoid space.
HRCT
MRI
IVP
Myelography