Diffusion weighted MRI for treatment response evaluation in GIST patients with correlation to PET/CT: pilot study

Congress:

ECR 2012

Poster Number:

C-1906

Type:

Scientific Paper

Keywords:

Gastrointestinal tract, MR-Diffusion/Perfusion, PET-CT

Authors:

N. Gong, C. S. Wong, Y. C. T. Chu, J. Gu; Hong Kong/CN

DOI:

10.1594/ecr2012/C-1906

DOI-Link:

https://dx.doi.org/10.1594/ecr2012/C-1906

Fig. 1: Figure 1. A typical lesion of complete response (lesion No. 7). The SUVmax...

Fig. 2: Figure 2. A typical lesion of partial response (lesion No. 29). The SUVmax...

Fig. 3: Figure 3. Linear regression between SUVmax and ADCmean_thr (10-3 mm2/s) in...

Fig. 4: Figure 4. Linear regression between SUVmean and ADCmean_thr (10-3 mm2/s) in...

Purpose

Previous study focusing on the performance of DW MRI in GIST at diagnosis found several significant correlations between ADC parameters and SUV parameters, which suggests the potential utilization of DWI as an alternative functional imaging tool to PET/CT in GIST diagnosis. However, no follow-up data has been presented. Tumor treatment response assessment in GIST is utmost important. In the present pilot study, by comparing ADC parameters derived from DWI and SUV parameters derived from PET/CT for treatment response monitoring and response prediction, we tried to...

Methods and Materials

A.Patients and Treatment Between September 2010 and November 2011, 7 patients with histopathological proof of metastatic GIST in a single institution (***) were enrolled into the present study. Patients with contraindication to MRI and claustrophobia were excluded. All recruited patients underwent PET/CT scans first and then MRI scans at diagnosis. Totally 37 lesions were found. And they were later treated with Imatinib Mesylate. Between December 2010 and November 2011, 6 out of 7 patients had follow-up MRI and PET/CT examinations within an average interval of...

Results

Table 1.Lesions’ treatment response in PET/CT and MRI Response category PET/CT MRI Size only Size plus ADCmean Size plus ADCmean_thr Complete Response 44.4% (16/36) 44.4% (16/36) 44.4% (16/36) 44.4% (16/36) Partial Response 47.2% (17/36) 13.9% (5/36) 33.3% (12/36) 41.7% (15/36) Stable Disease 8.3% (3/36) 41.7% (15/36) 22.2% (8/36) 13.9% (5/36) Kappa value --- 0.45 0.69 0.91 Table 2.Summary of lesions’ measurements at initial and follow-up imaging (n=20) PET/CT MRI LD SUVmax SUVmean TLG LD ADCmean ADCmean_thr TDI_thr Diagnosis 6.96 ± 3.64 3.47 ± 1.50 3.47...

Conclusion

Our results show that DWI measurement of ADCmean_thr was strongly significantly correlated with PET/CT measurements of SUVmax and SUVmean in both diagnosis and follow-up imaging. And △ADCmean_thr was significantly correlated with △SUVmax and △SUVmean. In addition, △TDI_thr correlate significantly with △TLG. Pre-treatment TDI_thr outperforms SUVmean in treatment response prediction. These findings indicate that DWI may serve as an alternative to PET/CT for tumor detection, tumor characterization, treatment response monitoring, and treatment response prediction in GIST patients.

References

1. Demetri GD, Benjamin RS, Blanke CD, et al. NCCN Task Force report: management of patients with gastrointestinal stromal tumor (GIST)--update of the NCCN clinical practice guidelines. J Natl Compr Canc Netw 2007;5 Suppl 2:S1-29; quiz S30. 2. DeMatteo RP, Lewis JJ, Leung D, Mudan SS, Woodruff JM, Brennan MF. Two hundred gastrointestinal stromal tumors: recurrence patterns and prognostic factors for survival. Ann Surg 2000;231(1):51-58. 3. Nikfarjam M, Kimchi E, Shereef S, et al. Surgical outcomes of patients with gastrointestinal stromal tumors in the era...