Does I-131-MIBG underestimate skeletal disease burden in neuroblastoma?
BACKGROUND
Controversy persists as to the need for both MIBG and bone scanning in routine evaluation of neuroblastoma.


OBJECTIVE
To compare the efficacy of I-131- metaiodobenzylguanidine (MIBG) scan against that of conventional Tc99m- methylene diphosphonate (MDP) bone scan for the detection of skeletal deposition of neuroblastoma.


METHODS
The study included 57 patients (36 boys, 21 girls: age range 1-14 years) of neuroblastoma who underwent both bone scan with Tc99m-MDP and I-131-MIBG scan within 15 days of each other at presentation and during follow-up.


RESULTS
At presentation 11(19.2%) patients had evidence of skeletal metastases on MDP scan against 7 patients who showed bony secondaries on MIBG scan. Of the 7 patients, with positive MIBG and MDP scans, MDP scan detected 11 sites whereas MIBG scan detected 7 sites. On follow-up study, 3 patients with initial abnormal MDP scan but normal MIBG scan, developed skeletal metastases detectable on MIBG scan, whereas 3 of the 46 patients who had normal MDP and MIBG scan at presentation; developed skeletal metastases detectable on MDP scan. MIBG scan was concordant in 2 of them but was normal in the third patient.


CONCLUSIONS
I-131-MIBG underestimates skeletal disease burden in neuroblastoma. Therefore, Tc99m-MDP bone scan should remain a part of routine assessment of patients with neuroblastoma.
Barai
S
S
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India. danzig@rediffmail.com
Bandopadhayaya
G P
GP
Malhotra
A
A
Agarwal
S
S
Kumar
R
R
Dhanapathi
H
H
D019797:3-Iodobenzylguanidine; D000293:Adolescent; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009447:Neuroblastoma / Q000000981:diagnostic imaging / Q000556:secondary*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D013669:Technetium Tc 99m Medronate