Looking beyond the thrombus: essentials of pulmonary artery imaging on CT.

BACKGROUND: Pulmonary arteries are not just affected by thrombus. Congenital and acquired conditions can also involve the pulmonary arteries. An awareness of these conditions is important for the radiologist interpreting chest computed tomography (CT). METHODS: The anatomy of the pulmonary arteries was reviewed. CT and magnetic resonance (MR) acquisition protocols for imaging the pulmonary arteries were discussed. The imaging appearances of congenital and acquired anomalies involving the pulmonary arteries, using CT and other modalities, were presented. RESULTS: Imaging features of congenital anomalies presented include pulmonary agenesis, partial pulmonary artery agenesis, patent ductus arteriosus, pulmonary artery sling, congenital pulmonary artery stenosis and coronary to pulmonary artery fistula. Acquired pulmonary artery anomalies discussed include arteritis, infected aneurysm and sarcoma. Pulmonary artery filling defects besides thromboembolism are also discussed, including foreign body emboli. Imaging features of bronchogenic carcinoma and mediastinal fibrosis demonstrating compression of the pulmonary arteries are presented, followed by a brief discussion of post repair appearance of the pulmonary arteries for congenital heart disease. CONCLUSIONS: Congenital and acquired pulmonary artery anomalies have a characteristic appearance on a variety of imaging modalities. An acquaintance with the imaging features of these anomalies is needed to avoid misinterpretation and reach the correct diagnosis. Teaching Points • Discuss a variety of congenital and acquired anomalies of the pulmonary arteries. • Discuss the imaging appearance of the presented congenital or acquired pulmonary artery anomalies. • Describe CT and MR acquisition protocols for imaging the pulmonary arteries. • Review the anatomy of the pulmonary arteries.

Breast metastases to thyroid gland.

Metastases to the thyroid gland are uncommon. We present the sonographic features of metastatic breast adenocarcinoma to the thyroid in a 67-year-old woman. The lesion measured up to 0.9 cm in diameter, contained an echogenic focus with associated ring-down, and was predominantly cystic, thereby resembling a benign nodule. Because of the patient's history of breast adenocarcinoma, the nodule nevertheless underwent fine-needle aspiration. The unusual appearance of the thyroid nodule underscores the importance of considering patient history in deciding whether obtaining tissue diagnosis of thyroid nodules is warranted.

Hip anatomic variants that may mimic abnormalities at MRI: labral variants.

OBJECTIVE: Normal anatomic variants of the acetabular labrum are observed on MR images and include labral variants, several sublabral sulci, and perilabral sulcus. Because variants can be misidentified as labral abnormalities such as labral tears, the radiologist needs to avoid the pitfall of mistaking variants as abnormalities. CONCLUSION: The hip has multiple anatomic variants that can mimic abnormalities at hip MRI. The labrum has several anatomic variants that can be confused with true labral tears.

Hip anatomic variants that may mimic pathologic entities on MRI: nonlabral variants.

OBJECTIVE: The hip has several anatomic variants that may be mistaken for pathologic abnormalities. The radiologist needs to be able to distinguish these variants from true abnormalities. In this review, we present nonlabral variants of the hip that can be seen on MRI. CONCLUSION: The hip has multiple anatomic variants that may mimic disease on hip MRI. Like labral variants, nonlabral variants can be confused for true abnormalities.