Are contrast media required for (68)Ga-DOTATOC PET/CT in patients with neuroendocrine tumours of the abdomen?

Riferimento: 
Eur Radiol. 2012 Apr;22(4):938-46.
Autori: 
Mayerhoefer ME, Schuetz M, Magnaldi S, Weber M, Trattnig S, Karanikas G.
Fonte: 
Eur Radiol. 2012 Apr;22(4):938-46.
Anno: 
2012
Azione: 
Valore del mezzo di contrasto per via endovenosa 68Ga-DOTA-Phe(1)-Tyr(3)-octreotide nella 68Ga-DOTATOC - PET/TC per l'individuazione dei tumori neuroendocrini addominali (NET).
Target: 
68Ga-DOTA-Phe(1)-Tyr(3)-octreotide/tumori neuroendocrini addominali.

ABSTRACT:
OBJECTIVES::
To determine the value of intravenous contrast medium in (68)Ga-DOTA-Phe(1)-Tyr(3)-octreotide - (68)Ga-DOTATOC - PET/CT for the detection of abdominal neuroendocrine tumours (NET).:
METHODS::
In fifty-five patients with known or suspected NETs of the abdomen PET/CT was performed on a 64-row multi-detector hybrid system. For PET, 150 MBq of (68)Ga-DOTATOC were injected intravenously. Full-dose unenhanced, and arterial- and venous-phase contrast-enhanced CT images were obtained. Unenhanced and contrast-enhanced PET/CT images were evaluated separately for the presence of NETs on a per-region basis, by two separate teams with different experience levels.:
RESULTS::
On unenhanced PET/CT, sensitivity and specificity ranged from 89.3% (junior team) to 92% (senior team), and 99.1% (junior team) to 99.2% (senior team), respectively. On contrast-enhanced PET/CT, sensitivity and specificity ranged from 92.3% (junior team) to 98.5% (senior team), and 99.4% (junior team) to 99.5% (senior team), respectively. These increases in sensitivity and specificity, due to the use of contrast-enhanced images, were statistically significant (P < 0.05).:
CONCLUSIONS::
Intravenous contrast medium only moderately, aleit significantly, improves the sensitivity of (68)Ga-DOTATOC PET/CT for the detection of abdominal NETs, and hardly affects specificity. Thus, while contrast enhancement is justified to achieve maximum sensitivity, unenhanced images may be sufficient for routine PET/CT in NET patients.:
KEY POINTS:
Contrast media moderately improve the sensitivity of (68)Ga-DOTATOC PET/CT for neuroendocrine tumours. Contrast media hardly affect the specificity of (68)Ga-DOTATOC PET/CT for neuroendocrine tumours. Unenhanced PET/CT is sufficient for routine imaging of patients with neuroendocrine tumours.