The Diagnostic Usefulness of 131I-SPECT/CT at Both Radioiodine Ablation and during Long-Term Follow-Up in Patients Thyroidectomized for Differentiated Thyroid Carcinoma: Analysis of Tissue Risk Factors Ascertained at Surgery and Correlated with Metastasis Appearance

Abstract

131I Single-photon emission computerized tomography/computerized tomography (SPECT/CT) in the management of patients thyroidectomized for differentiated thyroid carcinoma (DTC) was further investigated. Retrospectively, 106 consecutive DTC patients were enrolled at the first radioiodine ablation, 24 at high risk (H), 61 at low risk (L) and 21 at very low risk (VL). 131I whole-body scan (WBS) and SPECT/CT were performed after therapeutic doses using a hybrid dual-head gamma camera. At ablation, SPECT/CT correctly classified 49 metastases in 17/106 patients with a significantly (p < 0.001) more elevated number than WBS which evidenced 32/49 foci in 13/17 cases. In this case, 86/106 patients could be monitored in the follow-up including 13/17 cases with metastases already at post-therapeutic scans. SPECT/CT after radioiodine diagnostic doses more correctly than WBS ascertained disease progression in 4/13 patients, stable disease in other 4/13 cases and disease improvement in the remaining 5/13 cases. Further 13/86 patients with only residues at post-therapeutic scans showed at SPECT/CT 16 neck lymph node (LN) metastases, three unclear and 13 occult at WBS. Significant involvement of some tissue risk factors with metastasis appearance was observed, such as minimal extrathyroid tumor extension and neck LN metastases. These risk factors should be carefully considered in DTC patient follow-up where 131I-SPECT/CT routinely use is suggested as a support tool of WBS.

A Comparative Follow-Up Study of Patients with Papillary Thyroid Carcinoma Associated or Not with Graves’ Disease

“…These results are in agreement with the data reported also by other authors who observed that multifocality/multicentricity in their PC/GD series was not associated with disease recurrent/persistence during follow-up nor with a significant increase in the risk of DTC-related mortality [ 14 , 24 ]. However, in other studies on larger case series, multifocality, together with other risk factors, including a few cases with GD, was associated with metastasis appearance in the follow-up of PC patients [ 47 , 51 ].…”

“…Metastases from DTC after thyroidectomy and radioiodine ablation are usually identified using 131 I whole-body scan (WBS) [ 34 , 35 , 36 ] and the more recent SPECT/CT before [ 37 , 38 , 39 , 40 ] and after ablation [ 41 , 42 , 43 , 44 , 45 , 46 , 47 ], as well as during long-term follow-up [ 48 , 49 , 50 , 51 ]. Together with nuclear medicine procedures, radiologic exams and sequential serum thyroglobulin assays were performed.…”

Clinical Implications of Adding SPECT/CT to Radioiodine Whole-Body Scan in Patients With Differentiated Thyroid Cancer

“…2A). 10,12,25,26,31,37,38 Meta-analysis of 4 studies, encompassing a total of 230 extracervical lesions, indicated that adding SPECT/CT to WBS resulted in a 20% increase in conclusive readings compared with WBS alone (RR, 1.20; 95% CI, 1.13-1.28; P < 0.00001) (Fig. 2B).…”

Towards an era of precise diagnosis and treatment: Role of novel molecular modification-based imaging and therapy for dedifferentiated thyroid cancer

“…A widely used radioisotope, radioiodine, plays a critical role in the diagnosis and treatment of DTC, such as 123 I, 124 I, and 131 I. 131 I SPECT/CT has become a routine tool for visualizing the lesions and evaluating distant metastases in patients receiving radioactive iodine therapy ( 29 ). 124 I PET/CT could improve the sensitivity and spatial resolution of SPECT/CT, leading to superior diagnostic performance of post-therapy 131I-WBS.…”