Ultrasound Guidelines for Various Clinical Scenarios

Breast Imaging

• For women ≥30 years with a palpable breast mass, both diagnostic mammogram and ultrasound are recommended for accurate diagnosis, as suggested by the American College of Radiology 1
• For women <30 years with a palpable breast mass, ultrasound is the preferred initial imaging modality due to its sensitivity in detecting breast abnormalities, according to the National Comprehensive Cancer Network 1, 2
• For men ≥25 years with pathologic nipple discharge, mammography/digital breast tomosynthesis should be performed initially, with ultrasound added as indicated, as recommended by the American College of Radiology 3, 4
• For pathologic nipple discharge in women ≥40 years, mammography or digital breast tomosynthesis should be the initial examination, usually complemented by ultrasound, as suggested by the American College of Radiology 3, 4
• For women 30-39 years with pathologic discharge, either mammogram or ultrasound may be used as the initial examination based on institutional preference, according to the American College of Radiology 3, 4
• For women <30 years with pathologic discharge, ultrasound should be the initial examination, as recommended by the American College of Radiology 3, 4
• For asymptomatic patients with breast implants (any age), imaging is not recommended, as stated by the American College of Radiology 5
• For patients with suspected saline implant complications and equivocal clinical findings, ultrasound is the examination of choice for those <30 years, while mammography/digital breast tomosynthesis is recommended for those ≥40 years, according to the American College of Radiology 5
• For patients with suspected silicone implant complications, MRI without contrast or ultrasound is used for those <30 years, while MRI without contrast or mammography/digital breast tomosynthesis is used for those ≥40 years, as recommended by the American College of Radiology 5

Venous Thrombosis Evaluation

• All patients should be evaluated for pretest probability of deep venous thrombosis (DVT) using clinical decision rules such as the Wells score, as suggested by the American Heart Association 6
• For patients with low (unlikely) pretest probability of DVT, obtaining a high-sensitivity D-dimer is appropriate before considering ultrasound, according to the American Heart Association 6
• Ultrasound is appropriate for patients with likely pretest probability of DVT, unlikely pretest probability of DVT with a positive D-dimer, or cases where pretest probability was not assessed, as recommended by the American Heart Association 6

Gynecologic Imaging

• Combined transabdominal and transvaginal ultrasound of the pelvis with Doppler is the most appropriate initial imaging study for patients with abnormal uterine bleeding, as suggested by the American College of Radiology 7
• If the uterus is incompletely visualized with the initial ultrasound, MRI of the pelvis without and with contrast is the next appropriate imaging study, according to the American College of Radiology 7
• If a polyp is suspected on the original ultrasound, sonohysterography can be performed, as recommended by the American College of Radiology 7, 1

Early Pregnancy Evaluation

• For stable patients in the first trimester of pregnancy with abdominal pain or vaginal bleeding, ultrasound is indicated, as suggested by the American College of Emergency Physicians 8
• For patients with a β-hCG level below the discriminatory threshold (typically 1,500 mIU/mL), ultrasound may still be beneficial, with a sensitivity of approximately 33% and specificity of approximately 98% for diagnosing intrauterine pregnancy, according to the American College of Emergency Physicians 8
• The decision to perform ultrasound should consider the patient's ability to arrange appropriate follow-up, as recommended by the American College of Emergency Physicians 8

Liver Imaging

• Ultrasound every 6 months is universally recommended for hepatocellular carcinoma (HCC) surveillance in at-risk populations, such as cirrhotic patients and chronic HBV or HCV carriers, as suggested by the American Association for the Study of Liver Diseases 9
• Some guidelines recommend combining ultrasound with alpha-fetoprotein (AFP) measurement every 6 months, according to the American Association for the Study of Liver Diseases 9
• CT or MRI may be used in select patients with a high likelihood of having an inadequate ultrasound, as recommended by the American Association for the Study of Liver Diseases 9

Special Populations

• For pregnant women with isolated soft markers on previous ultrasound (such as choroid plexus cysts), no further ultrasound evaluation is needed if serum or cfDNA screening results are negative, as suggested by the American College of Obstetricians and Gynecologists 1
• For transfeminine (male-to-female) patients, mammography/DBT and ultrasound are useful due to the increased incidence of breast cancer, according to the American College of Radiology 4