Table 1.

Benefits and limitations of clinical imaging modalities

Modality	Sensitivity	Penetration depth	Spatial resolution	Advantages	Disadvantages
Ultrasound	Moderate	Low	1 mm	Widely available; inexpensive; no ionizing radiation; real-time imaging	Limited molecular probes; small field of view; operator dependent
MR	Moderate	No limit	<1–3 mm3	No ionizing radiation; high spatial resolution	Susceptibility to motion artifacts; limited molecular probes; not compatible for patients with metallic implants or renal insufficiency; long imaging times
SPECT	High	No limit	~5–8 mm3	High sensitivity; multiple radiotracers available for molecular imaging; ability to serially monitor long half-life isotopes	Exposure to ionizing radiation; attenuation from low-energy photons
PET	High	No limit	~3–5 mm3	High sensitivity; established methods for attenuation correction; accurate and precise quantification	Exposure to ionizing radiation; need for on-site cyclotron or generator; advanced radiochemistry
CT	Limited	No limit	<1 mm3	High spatial resolution can be combined with other modalities (PET/SPECT)	Exposure to ionizing radiation; patient sensitivity to iodinated contrast agents
OCT	High	Low	10–20 μm	High-resolution intravascular imaging; superior plaque imaging	Catheterization required; poor penetration depth

Modified from Naumova et al. [2]