Abstract:
We sought to determine whether PET/CT
imaging with 68Ga-citrate could be of value in distinguishing
benign from malignant lung pathology in a setting
with a high prevalence of granulomatous diseases.
METHODS : Thirty-six consecutive patients with indeterminate
lung lesions prospectively underwent dual time point
(60 and 120 min) 68Ga-citrate PET/CT study prior to lung
biopsy. Qualitative and semi-quantitative measures of tracer
uptake in the lung lesions (SUVmax) were compared to
the histopathology in order to establish an imaging pattern
to distinguish benign from malignant lesions. RESULTS : Fourteen patients (38.9 %) were diagnosed with a
malignant lesion, 12 (33.3 %) with tuberculosis (TB), and
10 participants (27.8 %) with other benign lung lesions. At
60-min post-injection, patients who were diagnosed with a
malignant lesion (n = 14) demonstrated a mean SUVmax
of 3.36 ± 1.14, with a median value of 3.04 (min = 1.56,
max = 4.65).Those with TB (n = 12) demonstrated a
SUVmax of 3.99 ± 2.28, and a median value of 3.71
(pct25 = 2.19, pct75 = 4.95). In patients with other benign
lesions (n = 10), the following values were observed: a
SUVmax of 2.70 ± 1.31, a median value of 2.50
(pct25 = 1.76, pct75 = 3.59). The mean values of these
three types of pathology were not statistically significant
(p = 0.1919), and therefore the SUVmax could not be used
to accurately distinguish between these lesions using both
early and delayed imaging.
CONCLUSION : This study, as the first 68Ga-citrate PET/CT
in humans for the in vivo imaging of lung pathology,
demonstrated its potential for the detection of both
malignancy and TB. However, 68Ga-citrate seemed incapable
of providing a clear distinction between malignant
and benign lung lesions in a setting with a high prevalence
of granulomatous diseases such as TB.
