Characterization of radiologically indeterminate lung lesions: 99mTc-depreotide SPECT versus 18F-FDG PET.
OBJECTIVE
To evaluate the diagnostic accuracy of 99m Tc-depreotide vs PET-18FDG scans in patients with suspicion of lung cancer.


METHODS
Prospective study in 29 patients (age: 38-80 years) diagnosed of inderteminate lung lesions. Diagnosis was established by histology based on samples of surgical resection, fine needle aspiration (FNA) or broncoalveolar lavage (BAL). Within a maximum of 10 days, without pre-established fixed order the following exams were performed: 1) Whole body and chest SPECT-CT with Tc-depreótide (DEP-SPECT) and 2) PET-CT study with F-FDG (PET-FDG). Every exam was evaluated by Nuclear Medicine especialist blinded to patient data.


RESULTS
Malignancy was confirmed in 20 patients. PET-FDG was positive in all cases. DEP-SPECT was positive in 17 and falselly negative in 3, one carcinoid tumor, one undifferentiated non-small cell adenocarcinoma, and a moderately differentiated adenocarcinoma. In the remaining 9 patients benignancy was confirmed; both studies were normal in 8 and falselly positive in one case of non-specific inflammatory lung process. In 9 out of the 20 cases with malignancy extrapulmonar uptake was seen, with a total number of 19 lesions. In two cases the extrapulmonar uptake were non ganglionar metastasis (bone and adrenal) and in 7 due to mediastinic ganglionar involvement. ROC analysis using peak SUV FDG (cut-off point of 3.5) uptake and target/background depreotide uptake (cut-off point of 1.3) provided, sensitivity and specificity values of 95% and 89% of 84% and 88% for PET and SPECT respectively. It does not exist statistically significant differences between both methods (Z-test SPSS). In summary, FDG-PET has a greater sensitivity and diagnostic accuracy for assessing malignancy of indeterminate lung lesions, and for detection of extrapulmonary involvement, DEP-SPECT represents a good diagnostic alternative for centers where PET is not available.
Ferran
Nuria
N
Hospitalet de Llobregat, Hospital Universitari de Bellvitge-Idibell, Spain.
Ricart
Yvonne
Y
Lopez
Marta
M
Martinez-Ballarin
Ignacio
I
Roca
Manel
M
Gámez
Cristina
C
Carrerea
David
D
Guirao
Sara
S
Leon
Alejandro Fernandez
AF
Martin-Comin
Jose
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D011859:Radiography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013004:Somatostatin; C444119:technetium Tc 99m depreotide