Utility of PET/neck MRI digital fusion images in the management of recurrent or persistent thyroid cancer.
BACKGROUND
Approximately 30% of thyroid cancer patients present with reappearing disease within 40 years of initial diagnosis. Hence, sensitive postsurgical monitoring techniques are imperative to successful long-term care. The objective of this study was to assess the added clinical utility of a combined positron emission tomography/magnetic resonance imaging (PET/MRI) of the neck in conjunction with standard imaging in the detection of recurrent thyroid carcinoma. We define standard imaging as a neck sonogram, 131I scan, computed tomography, and MRI.


METHODS
This study included 34 patients treated for thyroid cancer at Washington Hospital Center. All patients had previously undergone near-total or total thyroidectomy, standard follow-up imaging studies, and laboratory studies. Twenty-nine of thirty-four patients had received at least one 131I treatment prior to the study. Each patient received a PET and MRI scan, and these images were subsequently digitally fused.


RESULTS
Individually and blinded, four endocrinologists retrospectively reviewed all information in patient charts prior to PET and PET/MRI coregistration. A clinical assessment and treatment plan were devised with these data. Following the initial assessment, the endocrinologists were provided results from the PET and PET/MRI fusion studies and asked to make a revised assessment and treatment plan. For each patient, the physicians categorized PET/MRI fusion results as providing new information that altered the initial treatment plan, providing new information that confirmed the initial treatment plan, or providing no additional information. On average, PET/MRI coregistration provided additional information that altered the treatment plan in 46% of the cases, provided additional information that confirmed the treatment plan in 36% of cases, and did not provide any additional information in 18% of cases.


CONCLUSIONS
The combination of structural and functional data that PET/neck MRI fusion offers provided further information in an overwhelming majority of thyroid cancer patients in this study. Thus PET/MRI can be a useful tool in surgical planning, radioactive iodine therapy decisions, and determining the level of follow-up necessary for each patient.
Seiboth
Laura
L
Endocrine Medicine Section, Washington Hospital Center, Georgetown University Medical Center, Washington, DC 20010, USA.
Van Nostrand
Douglas
D
Wartofsky
Leonard
L
Ousman
Yasser
Y
Jonklaas
Jacqueline
J
Butler
Calvin
C
Atkins
Frank
F
Burman
Kenneth
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018579:Patient Selection; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D013965:Thyroidectomy; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18