Clinical relevance of single-photon emission computed tomography/computed tomography of the neck and thorax in postablation (131)I scintigraphy for thyroid cancer.
BACKGROUND
In patients with differentiated thyroid carcinoma, postablation (131)I scintigraphy aims to detect residual neck disease and distant metastases, usually found in lungs and bones. New hybrid single-photon emission computed tomography/computed tomography (SPECT-CT) cameras that permit functional and anatomical image fusion may improve its clinical relevance.


OBJECTIVE
Our objective was to test the added value of neck and thorax SPECT-spiral CT to whole-body scan (WBS) in postablation (131)I scintigraphy.


METHODS
This was a single-referral-center prospective study with a median follow-up of 21 months.


METHODS
Postablation (131)I WBS and neck and thorax SPECT-CT were performed in 55 consecutive patients treated in 2006. WBS and SPECT-CT data were blindly reviewed, scored negative (benign), positive (malignant), or indeterminate and were correlated to the patient outcome.


RESULTS
At patient level, WBS and SPECT-CT were negative in 67 and 78% of patients, positive in 4 and 15%, and indeterminate in 29 and 7%, respectively. Overall, nine patients (16%) presented treatment failure (persistent or recurrent disease) 1-16 months after radioiodine ablation. In the 16 patients with indeterminate WBS, negative SPECT-CT ruled out suspicion of disease in nine of nine patients, and positive SPECT-CT confirmed malignant lesions in four of five patients. Positive SPECT-CT predicted treatment failure better than positive WBS (McNemar's test, P = 0.03).


CONCLUSIONS
This study demonstrates the complementary role of neck and thorax SPECT-CT to WBS in postablation (131)I scintigraphy. Because SPECT-CT allows one to confirm or to rule out residual disease in most cases where WBS remains indeterminate, we recommend its use when available.
Aide
Nicolas
N
Department of Nuclear Medicine and Thyroid Unit, Centre François Baclesse, F-14076 Caen Cedex 05, France.
Heutte
Natacha
N
Rame
Jean-Pierre
JP
Rousseau
Elise
E
Loiseau
Cédric
C
Henry-Amar
Michel
M
Bardet
Stéphane
S
D055011:Ablation Techniques / Q000379:methods; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011379:Prognosis; D012189:Retrospective Studies; D013909:Thorax / Q000000981:diagnostic imaging*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D015899:Tomography, Emission-Computed, Single-Photon; D051598:Whole Body Imaging / Q000379:methods; D055815:Young Adult
D007457:Iodine Radioisotopes