Value of CT thallium-201 SPECT fusion imaging over SPECT alone for detection and localization of nasopharyngeal and maxillary cancers.
OBJECTIVE
The purpose of this study was to investigate the incremental clinical utility of CT and high-resolution SPECT fusion imaging.


METHODS
Eighteen patients with nasopharyngeal cancer or cancers around the maxilla were scanned with high-resolution SPECT at the time of initial diagnosis (18 studies) and during follow-up after chemoradiotherapy (23 studies). SPECT results were compared with histologic findings or the findings of other imaging techniques. In addition, automatic image registration without fiducial markers was performed from CT and SPECT data, and the effect of fusion imaging on the localization of abnormalities was evaluated.


RESULTS
All of the original 18 untreated lesions showed high uptake. Recurrent tumors had a tendency to show high uptake (seven of nine patients), whereas little or no uptake generally represented no recurrence (12 of 14 patients) (chi-square test with Yates correction: chi2 = 6.80, p < 0.01). In two patients, physiologic uptake in the unilateral prevertebral muscle was revealed on image fusion. In four of the nine recurrent nasopharyngeal cancers (44%), SPECT alone could not determine abnormalities in uptake sites, whereas CT/SPECT fusion imaging clearly localized the sites and was helpful for treatment strategy.


CONCLUSIONS
High-resolution thallium-201 (201Tl) SPECT has a very high detection rate in patients with nasopharyngeal cancer and cancers around the maxilla. However, the anatomic identification or localization of the uptake sites is sometimes difficult without CT/SPECT fusion imaging. This technique without external markers is practically feasible to generate clinically valid fusion images.
Nakahara
Tadaki
T
Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan 160-8582. n-tadaki0909@k6.dion.ne.jp
Shigematsu
Naoyuki
N
Fujii
Masato
M
Kunieda
Etsuo
E
Suzuki
Takayuki
T
Tanaka
Chikako
C
Hashimoto
Jun
J
Kubo
Atsushi
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008444:Maxillary Sinus Neoplasms / Q000000981:diagnostic imaging*; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D013794:Thallium Radioisotopes