Morphological imaging in the localization of neuroendocrine gastroenteropancreatic tumors found by somatostatin receptor scintigraphy.
OBJECTIVE
To evaluate the necessity of morphological images (MI) in reading somatostatin receptor scintigraphy (SRS) in patients with suspected neuroendocrine gastroenteropancreatic (GEP) tumors.


METHODS
A Japanese multicenter clinical trial of SRS was conducted in 40 patients with suspected GEP tumors. Three experienced radiologists interpreted the images in three separate sessions in a blinded manner (1: SRS images alone, 2: MI alone, 3: SRS and MI analyzed simultaneously), and the reading results of each session were compared. In addition, the diagnostic abilities of SRS, MI and SRS alone and simultaneous SRS and MI readings were compared for patients where final diagnosis was obtained.


RESULTS
SRS detected more suspected lesions (positive or inconclusive uptake) than morphological images did (51 vs 27 lesions), but included many physiological uptakes detected as positive or inconclusive uptakes. Combined reading of SRS and morphological images helped to correctly recognize these physiological uptakes, and also helped in determining the anatomical localization of the abnormal uptakes. Combined reading of SRS and morphological images gave the highest diagnostic impact.


CONCLUSIONS
The sensitivity of SRS with regard to GEP is high. However the specificity is very low. Morphologic imaging is necessary for the exclusion of physiological uptake and correct anatomic location of an abnormal tracer uptake. The combined reading of SRS and morphologic imaging studies gives the highest diagnostic impact.
Department of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. saga@kuhp.kyoto-u.ac.jp
T
T
Saga
A
A
Shimatsu
K
K
Koizumi
T
T
Ichikawa
K
K
Yamamoto
S
S
Noguchi
R
R
Doi
M
M
Ishibashi
R
R
Machinami
K
K
Nakamura
H
H
Sakahara
K
K
Endo
D000230:Adenocarcinoma / Q000175:diagnosis*; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis*; D041981:Gastrointestinal Tract / Q000000981:diagnostic imaging; D006801:Humans; D007205:Indium Radioisotopes; D007340:Insulinoma / Q000175:diagnosis*; D007564:Japan; D018358:Neuroendocrine Tumors / Q000175:diagnosis*; D015588:Observer Variation; D010179:Pancreas / Q000000981:diagnostic imaging*; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D017481:Receptors, Somatostatin / Q000032:analysis*; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods
D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; D013004:Somatostatin; C081788:pentetreotide