TSH suppression aggravates arterial inflammation - an 18F-FDG PET study in thyroid carcinoma patients.

Abstract

PURPOSE:

We aimed to investigate the influence of both hypothyroidism and thyroid-stimulating hormone (TSH) suppression on vascular inflammation, as assessed with 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT).

METHODS:

Ten thyroid carcinoma patients underwent an 18F-FDG PET/CT during post-thyroidectomy hypothyroidism and during thyrotropin (TSH) suppression after 131I (radioiodine) ablation therapy. We analysed the 18F-FDG uptake in the carotids, aortic arch, ascending, descending, and abdominal aorta to investigate the effects of thyroid hormone status on arterial inflammation. Target-to-background ratios (TBRs) corrected for blood pool activity were established for all arterial territories. Results were further compared to euthyroid historic control subjects.

RESULTS:

In general, there was a trend towards higher vascular TBRs during TSH suppression than during hypothyroidism (TBRmax all vessels = 1.6 and 1.8, respectively, p = 0.058), suggesting a higher degree of arterial inflammation. In concurrence with this, we found increased C-reactive protein (CRP) levels after levothyroxine treatment (CRP = 2.9 mg/l and 4.8 mg/l, p = 0.005). An exploratory comparison with euthyroid controls showed significant higher TBRs during TSH suppression for the carotids, aortic arch, thoracic descending aorta, and when all vascular territories were combined (TBRmaxp = 0.013, p = 0.016, p = 0.030 and p = 0.018 respectively).

CONCLUSIONS:

Arterial inflammation is increased during TSH suppression. This finding sheds new light on the underlying mechanism of the suspected increased risk of cardiovascular disease in patients with TSH suppression.

• Authors: Ellen Boswijk, Karin J C Sanders, Evie P M Broeders, Marlies de Ligt, Guy H E J Vijgen, Bas Havekes, Alma M A Mingels, Roel Wierts, Wouter D van Marken Lichtenbelt, Patrick Schrauwen, Felix M Mottaghy, Joachim E Wildberger, Jan Bucerius
• Journal: European journal of nuclear medicine and molecular imaging (Eur J Nucl Med Mol Imaging) Vol. 46 Issue 7 Pg. 1428-1438 (Jul 2019) ISSN: 1619-7089 [Electronic] Germany
• PMID: 30859432 (Publication Type: Journal Article, Observational Study)

Chemical References

• Iodine Radioisotopes
• Iodine-131
• Radiopharmaceuticals
• Fluorodeoxyglucose F18
• Thyrotropin
• C-Reactive Protein
• Thyroxine

Topics

• Adult
• Aged
• Arteritis
• C-Reactive Protein (analysis)
• Female
• Fluorodeoxyglucose F18
• Humans
• Hypothyroidism (complications, diagnostic imaging, etiology)
• Inflammation (complications)
• Iodine Radioisotopes
• Male
• Middle Aged
• Positron Emission Tomography Computed Tomography
• Prospective Studies
• Radiopharmaceuticals
• Thyroid Neoplasms (diagnostic imaging, surgery, therapy)
• Thyroidectomy
• Thyrotropin (antagonists & inhibitors)
• Thyroxine (therapeutic use)