Learning objectives
To review the typical features of a parathyroid adenoma on CT through a series of cases. Common (and uncommon) locations for adenomas and imaging pitfalls will be presented.
Background
Primary hyperparathyroidism is most commonly caused by a single parathyroid adenoma, which results in excess secretion of parathyroid hormone causing hypercalcaemia [1]. This disorder can be cured with surgical resection of the involved gland. In order to prevent complications, exclude multi-glandular disease and select patients for minimally invasive parathyroidectomy surgery, the surgeon needs precise localisation of the parathyroid adenoma preoperatively.
Four-dimensional (4D) CT is being increasingly used to enable accurate localisation of the parathyroid adenoma in eutopic and ectopic locations and to depict multiglandular disease....
Imaging findings OR Procedure details
4D CT consists of a CT of the neck and upper chest performed during multiple time points before and after contrast injection. Typically, the scans are acquired with non-contrast, arterial and venous phases. Some centres also use a delayed phase. Adenomas will typically demonstrate avid contrast enhancement on the arterial phase and show washout on the more delayed phases. The non-contrast scans are important to distinguish an adenoma from adjacent thyroid tissues which will be hyperdense on unenhanced images. Figure 1 demonstrates the typical enhancement...
Conclusion
Although traditionally the two primary modalities for parathyroid imaging are cervical US and nuclear scintigraphy, 4D CT is increasingly being used as an alternative investigation. This pictorial review highlights the typical contrast enhancement characteristics as well as the potential mimics and pitfalls that radiologists need to be aware of when reporting these studies.
Personal information
Dr Jennifer Gillespie, Radiologist, Department of Radiology, Royal Brisbane & Women's Hospital, Brisbane, Queensland, Australia
Dr Daniel Mac Manus,Senior House Officer, Royal Brisbane & Women's Hospital, Brisbane, Queensland, Australia
References
1. How to Perform Parathyroid 4D CT: Tips and Traps for Technique and Interpretation Jenny K. Hoang , Won-kyung Sung, Manisha Bahl, C. Douglas Phillips
2. Rodgers SE, Hunter GJ, Hamberg LM, et al. Improved preoperative planning for directed parathyroidectomy with 4-dimensional computed tomography. Surgery 2006;140(6): 932–940; discussion 940–941.
3. Beland MD, Mayo-Smith WW, Grand DJ, Machan JT, Monchik JM. Dynamic MDCT for localization of occult parathyroid adenomas in 26 patients with primary hyperparathyroidism. AJR Am J Roentgenol 2011;196(1):61–65.
4. Fakhran S, Brandstetter BF, Pryma...