Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off.
OBJECTIVE
To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas > or =10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off.


METHODS
84 patients, who underwent PET/CT and colonoscopy (n = 79)/sigmoidoscopy (n = 5) for (79 x 6 + 5 x 2) = 484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs.


RESULTS
Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n = 23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n = 10) the SUV(max) was > or =5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV(max).


CONCLUSIONS
FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV(max) > or = 5 improves the accuracy.
Luboldt
Wolfgang
W
Multiorgan Screening Foundation, Frankfurt, Germany. luboldt@screening.org
Volker
Teresa
T
Wiedemann
Bärbel
B
Zöphel
Klaus
K
Wehrmann
Ursula
U
Koch
Arne
A
Toussaint
Todd
T
Abolmaali
Nasreddin
N
Middendorp
Markus
M
Aust
Daniela
D
Kotzerke
Jörg
J
Grünwald
Frank
F
Vogl
Thomas J
TJ
Luboldt
Hans-Joachim
HJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D003110:Colonic Neoplasms / Q000175:diagnosis*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D019275:Radiopharmaceuticals; D016037:Single-Blind Method; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18