Aims and objectives
Sarcomas are heterogeneous tumor accounting for nearly 20% of all pediatric solid malignancies.
The vast majority are soft tissue sarcomas,
while malignant bone neoplasms account for around 10% [1].
The diagnostic and therapeutic management of pediatric sarcomas is complex and requires a multidisciplinary approach.
MRI is considered the main imaging technique for primary tumor assessment and for local recurrences detection while systemic staging is mostly based on Computed Tomography (CT) and Positron Emission Tomography/CT (PET/CT) [2].
Combining the benefits of morphological and high soft tissue...
Methods and materials
Pediatric patients with histologically proven sarcoma who underwent 18F-FDG PET/MRI (i.e.,
fully-integrated) for initial staging or re-staging were included in this retrospective study.
The MRI protocol of the PET/MR scan had to include at least the following sequences: axial Turbo Inversion Recovery Magnitude (TIRM),
axial Half-Fourier Acquisition Single-shot Turbo spin Echo imaging (HASTE),
coronal T1w Turbo Spin Echo (TSE),
pre-contrast and contrast enhanced axial Volumetric Interpolated Breath-hold Examination (VIBE) and axial whole body Diffusion Weighted Imaging (DWI).
Each examination was evaluated independently and then in...
Results
Sixteen patients met the inclusion criteria (nine males,
seven females; mean age 8.8 ± 4.9 years).
Histology revealed nine rhabdomyosarcoma,
two Ewing-sarcoma,
diffuse myofibromatosis,
chondroblastic osteosarcoma,
angiosarcoma,
extrarenal-rhabdoid tumor and undifferentiated sarcoma one each. The overall inter-observer agreement between the two teams turned out to be very high (κ=0.994).
Discordant results emerged only for the detection of a local lymph node in a patient affected by a rhabdoid-tumor and for two peritoneal metastases in a patient with angiosarcoma.
When compared to the reference standard,
PET/MRI...
Conclusion
Our preliminary results demonstrated that 18F-FDG PET/MRI with whole body DWI guarantees an excellent reliability and a high diagnostic performance for pediatric sarcomas.
Therefore,
considering also its low dose radiation exposure,
PET/MRI should be taken into account as one-stop shop for pediatric sarcomas at staging and restaging.
Further studies on a larger population are necessary not only to improve pulmonary MR imaging and thus increase the detection of lung metastases but also to fully assess the overall role of PET/MRI for pediatric sarcomas.
References
1.
Partovi S,
Chalian M,
Fergus N,
Kosmas C,
Zipp L,
Mansoori B et al.
Magnetic resonance/positron emission tomography (MR/PET) oncologic applications: bone and soft tissue sarcoma.
Semin Roentgenol.
2014 Oct;49(4):345-52.
2.
Casali PG,
Blay JY,
Bertuzzi A,
Bielack S,
Bjerkehagen B,
Bonvalot S et al (ESMO/European Sarcoma Network Working Group).
Soft tissue and visceral sarcomas: ESMO Clinical Practice Guidelines for diagnosis,
treatment and follow-up.
Ann Oncol.
2014 Sep;25 Suppl 3:iii102-12.
3.
Platzek I,
Beuthien-Baumann B,
Schramm G,
Maus J,
Laniado M,
Kotzerke J et...