Imaging in Stem Cell Transplant and Cell-based Therapy

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3.5 Diagnostic Use of MIBI

The diagnostic uses for^123 I-MIBG imaging are; confirmation of diagnosis, localiza-
tion for biopsy planning, prognostication of neuroblastoma when used as part of a
scoring system, response criteria monitoring, presence or absence of minimal resid-
ual disease, and surveillance follow up for disease recurrence.
Scoring systems which use MIBG scanning are listed in Table 3.1. In each of the
studies, MIBG scanning was evaluated for number of MIBG-avid sites as they
related to outcome. In one study, Ady et al. [ 11 ] showed that mid-induction scores
could predict overall response at the end of induction therapy. In another study, Suc
et al. [ 12 ] showed that 4 or more sites on MIBG scans were associated with a higher
risk for not achieving remission, while Matthay et al. [ 13 ] showed that three or more
sites identified patients at higher risk for not responding to treatment. In one study,
Katzenstein et al. [ 14 ] showed that MIBG scans correlated with outcome after stem
cell transplantation.
In addition to scoring systems,^123 I-MIBG scanning can also be used to identify
the type of metastatic spread, which may also relate to prognosis. MIBG scans pres-
ent in different patterns: ‘limited focal’ and ‘diffuse-metastatic’. The limited and
focal pattern (median 2 body parts affected) was found in patients with MYCN
amplification and correlates to better event-free and overall prognosis [ 15 ]. Whereas,
extensive diffuse pattern (median 11 body parts affected) was found mainly in
patients with single copy MYCN oncogene, and was associated with overall poorer
prognosis [ 15 ].
A recent Cochrane Review [ 16 ] evaluated all of the published studies done
through 2012 relating to either^123 I MIBG (SPECT) and/or^18 F-FDG
(^18 F-fludeoxyglucose) PET (CT) scanning as diagnostic studies in patients with
neuroblastoma. The investigators identified 11 high quality studies involving 621

Table 3.1 MIBI scoring system

Stage of NB Timing of MIBG scintigraphy Result

1 Stage IV

NB

MIBG scans at beginning, mid-course

(6 weeks), end of neoadjuvant

chemotherapy (12 weeks)

Mid-induction scores predict the

overall response of metastases at the

end of induction

2 Stage IV

NB

MIBG scan at diagnosis MIBG at diagnosis with four or more

spots was associated with higher risk

of failing to achieve remission

3 > 1 year

and Stage

IV NB

123I MIBG scans at diagnosis, after

two and four cycles of induction

therapy and before auto-SCT

Absolute and relative scores showed

correlation with overall pre-

transplantation response, bone

marrow response and EFS

4 High risk

NB

Post induction MIBG score in high

risk NB patients treated with

induction regimen, consolidated with

3 cycles of high dose therapy and

stem cell rescue.

MIBG scores >/= 3 following

induction identified NB patients

likely to relapse

3 Radiologic Procedures Used in Pediatric Stem Cell Transplantation