Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT studies for the diagnosis of uterine cancer recurrence.
OBJECTIVE
To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated (18)F-fluorodeoxyglucose (FDG) PET/CT studies for restaging of uterine cancer.


METHODS
A group of 100 women who had undergone treatment for uterine cervical (n=55) or endometrial cancer (n=45) underwent a conventional PET/CT scans with ldCT, and then a ceCT scan. Two observers retrospectively reviewed and interpreted the PET/ldCT and PET/ceCT images in consensus using a three-point grading scale (negative, equivocal, or positive) per patient and per lesion. Final diagnoses were obtained by histopathological examination, or clinical follow-up for at least 6 months.


RESULTS
Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/ceCT were 90% (27/30), 97% (68/70) and 95% (95/100), respectively, whereas those of PET/ldCT were 83% (25/30), 94% (66/70) and 91% (91/100), respectively. Sensitivity, specificity and accuracy did not significantly differ between two methods (McNemar test, p=0.48, p=0.48, and p=0.13, respectively). There were 52 sites of lesion recurrence: 12 pelvic lymph node (LN), 11 local recurrence, 8 peritoneum, 7 abdominal LN, 5 lung, 3 supraclavicular LN, 3 liver, 2 mediastinal LN, and 1 muscle and bone. The grading results for the 52 sites of recurrence were: negative 5, equivocal 0 and positive 47 for PET/ceCT, and negative 5, equivocal 4 and positive 43 for PET/ldCT, respectively. Four equivocal regions by PET/ldCT (local recurrence, pelvic LN metastasis, liver metastasis and muscle metastasis) were correctly interpreted as positive by PET/ceCT.


CONCLUSIONS
PET/ceCT is an accurate imaging modality for the assessment of uterine cancer recurrence. Its use reduces the frequency of equivocal interpretations.
Kitajima
Kazuhiro
K
Department of PET Diagnosis, Institute of Biomedical Research and Innovation, 2-2 Minatojima-Nakamachi, Chuo-ku, Kobe 650-0047, Japan. kitajima@med.kobe-u.ac.jp
Suzuki
Kayo
K
Nakamoto
Yuji
Y
Onishi
Yumiko
Y
Sakamoto
Setsu
S
Senda
Michio
M
Kita
Masato
M
Sugimura
Kazuro
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011829:Radiation Dosage; D012008:Recurrence; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging*
D003287:Contrast Media
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