Table 3.

Comparison of some commonly used imaging modalities in pregnancy based on reports from relevant studies^a

Imaging modality	Sensitivity	Specificity	Fetal dose of ionizing radiation (mGY)	Advantages	Limitations	References
Plain X-ray	30–88	43–87		Rapid	Limited indications	45, 46, 76, 81
1. Chest X-ray			0.002	Inexpensive	Low sensitivity for
2. Abdominal X-ray			1–3	Most useful for intestinal obstruction in pregnancy	bowel strangulation
Ultrasound	67%–100%	83%–96%	0	Availability Portability No ionizing radiation	Operator- dependent visualization impaired by gravid uterus	21, 77
CT scan	91%	90%		Availability	Ionizing radiation	78, 79
1. CT abdomen			4	Rapid	Expensive
2. CT abdomen with pelvis			25
MRI	100%	98%	0	No ionizing radiation	Limited availability Slower than CT Expensive	80

Note:

^aIonizing radiation dose is expressed as mGy.

Abbreviations: CT, computed tomography; MRI, magnetic resonance imaging.