Short summary

The purpose of this project is to examine, in a non-inferiority study, whether the combination of conventional ultrasound and contrast-enhanced ultrasound (CEUS) can replace the radiation-based imaging modalities that are currently used to localise pathological parathyroid glands prior to surgical removal in patients with primary hyperparathyroidism. 

Rationale

Primary hyperparathyroidism (pHPT) is an endocrinological disorder in which plasma calcium levels are abnormally high due to an autonomous overproduction of parathyroid hormone by one or more of the four parathyroid glands. The typical symptoms of the disease are renal stones and bone demineralization with the risk of developing pathological fractures. Other manifestations may be proximal muscle weakness, pancreatitis, hypertension, depression, anxiety, and neurocognitive deficits. In countries with readily available biochemical screening, many patients are diagnosed early and can potentially be treated before these serious symptoms occur. The only curative treatment for pHPT is surgical excision of abnormal parathyroid glands. 

For years, the surgical approach to pHPT consisted of an intraoperative exploration of both sides of the neck with identification and evaluation of all four parathyroid glands prior to removal of those deemed pathological. However, the large majority of patients suffer from only a single adenoma, and in recent years minimally invasive surgical approaches that target only one side or quadrant of the neck are increasingly used. The aim of a minimally invasive parathyroidectomy is to reduce the length of the incision and the rate of complications from surgical dissection in a complex anatomical area. 

For a focused minimally invasive parathyroidectomy to be possible, preoperative imaging must correctly localise all hyperactive parathyroid glands. This requires two separate out-patient visits. The first visit takes place at the Department of Nuclear Medicine where the following radiation-based imaging procedures are performed: an imaging procedure using two radioactive tracers (subtraction scintigraphy), a computerized X-ray scan (CT), and a three-dimensional imaging procedure (SPECT). The second visit takes place at the Department of Otolaryngology, Head and Neck Surgery where a surgeon performs a conventional ultrasound examination of the neck. 

Despite the many scans, the pathological parathyroid gland is not always localised prior to surgery, or the different imaging modalities may not be in agreement about the position of the pathological gland on the neck. 

A new and promising imaging modality consists of enhancing the conventional ultrasound examination with an intravenous contrast agent. The method is known as contrast-enhanced ultrasound (CEUS) and is widely used in abdominal ultrasound diagnostics. CEUS neither exposes patients to radiation nor to radioactive tracers, and it is both faster and less costly than the radiation-based imaging techniques.

We wish to examine, in a non-inferiority study, whether the combination of a conventional and a contrast-enhanced ultrasound examination of the neck can replace the radiation-based imaging modalities that are currently used to localise pathological parathyroid glands prior to surgical removal in patients with primary hyperparathyroidism.

Description of the cohort

Patients 18 years and older with primary hyperparathyroidism referred to the Department of Otorhinolaryngology, Head and Neck Surgery at Odense University Hospital for parathyroidectomy. 

Data and biological material

Age, gender, body mass index, smoking status, alcohol consumption, co-morbidity, parathyroid hormone levels, ionized calcium levels, histopathological diagnosis of intraoperatively excised specimens, concomitant thyroid pathology, prior neck surgery, pre-operative symptoms, duration of surgery, duration of hospital stay, surgical complications, weight, size, depth, and localisation of pathological parathyroid glands. The parathyroid hormone and ionized calcium levels from the standard control at the department of endocrinology approximately 6 months after surgery.

Collaborating researchers and departments

Department of Nuclear Medicine, Odense University Hospital

• Oke Gerke, cand.scient.oecon, PhD
• Sys Vestergaard, MD

Department of Otorhinolaryngology, Head and Neck Surgery, Odense University Hospital

• Anders Rørbæk Madsen, MD
• Christian Godballe, MD, PhD
• Helle Døssing, MD, PhD
• Mette Bay, MD
• Sanne Høxbroe Michaelsen, MD
• Viveque Egsgaard Nielsen, MD, PhD

Department of Radiology, Odense University Hospital

• Ole Graumann, MD, PhD

Publications associated with the project