Imaging Studies with and without Contrast

General Principles for Contrast Use

CT with intravenous contrast is recommended as the primary imaging modality for evaluating soft tissue pathology, inflammatory processes, infections, and neoplasms due to its ability to significantly improve characterization of masses and map lesion borders 1
MRI with contrast provides superior characterization of lesion components, enhances diagnostic accuracy, and improves detection of malignancy in soft tissue masses 2
Non-contrast studies are appropriate for initial evaluation of trauma, fractures, and in patients with contraindications to contrast agents 1
Performing both contrast and non-contrast CT in the same session is generally not recommended as it doubles radiation exposure with minimal additional diagnostic benefit 1

Suspected infection or abscess: Contrast-enhanced CT or MRI is preferred for detecting inflammatory processes and abscesses 1
Tumor/mass evaluation: Contrast is essential for characterizing lesions, determining tumor margins, and identifying viable tumor for biopsy 2
Diverticulitis: Abdominal and pelvic CT with contrast is preferred over CT without contrast, with a rating of 8/9 compared to 6/9 for CT without contrast 3
Osteomyelitis with draining sinus: MRI with and without contrast is the preferred study, with a rating of 9/9 4
Recurrent ovarian cancer: Contrast-enhanced CT is the modality of choice for detecting recurrence 5
Soft tissue masses: MRI without and with IV contrast is the preferred imaging study 2

Pregnancy: Ultrasound without contrast is the preferred imaging modality throughout pregnancy, and MRI without gadolinium is preferred over CT imaging when ultrasound is insufficient 6
Renal Function: Avoid iodinated contrast due to risk of contrast-induced nephropathy in patients with severe renal insufficiency 1
Initial evaluation of suspected soft tissue gas: CT without contrast is appropriate, with a rating of 6/9 4

For bone/structural evaluation, such as fractures, non-contrast study is preferred 1
For soft tissue pathology, such as masses or infections, contrast study is preferred 1, 2
In pregnancy, prefer ultrasound or non-contrast MRI 6
For diverticulitis, CT with contrast is preferred 3
For soft tissue mass, MRI with and without contrast is preferred 2