Diagnostic value of [68 Ga]Ga-DOTA-labeled-somatostatin analogue PET/MRI for detecting liver metastasis in patients with neuroendocrine tumors: a systematic review and meta-analysis

Objectives To determine the diagnostic value of [(68) Ga]Ga-DOTA-labeled-somatostatin analogue ([(68) Ga]Ga-DOTA-SSA) PET/MRI for detecting liver metastasis in patients with neuroendocrine tumor (NET) and to compare it with [(68) Ga]Ga-DOTA-SSA PET/CT. Methods A search of MEDLINE, EMBASE, and Cochrane was performed to identify original articles reporting the detection rate of [(68) Ga]Ga-DOTA-SSA PET/MRI for liver metastasis in comparison with PET/CT. The pooled detection rates for liver metastasis on PET/MRI and PET/CT were calculated and compared using a restricted maximum likelihood estimation of random-effects model. The pooled added value of PET/MRI in comparison with PET/CT was calculated. Sensitivity analysis and subgroup analysis were performed to explore causes of study heterogeneity. Results In the six included studies (638 liver metastases), the pooled detection rates for liver metastasis on [(68) Ga]Ga-DOTA-SSA PET/MRI and PET/CT were 93.5% (95% confidence interval [CI], 85.1-97.3%; I-2 = 84.8%) and 76.8% (95% CI, 64.8-85.6%; I-2 = 87.8%), respectively. PET/MRI had a significantly higher detection rate than PET/CT (p = 0.02), with 15.3% (95% CI, 8.0-27.4%) added value over PET/CT. After sensitivity analysis, the recalculated detection rates for liver metastasis were 94.8% (95% CI, 90.8-97.2%; I-2 = 42.1%) for PET/MRI and 80.0% (95% CI, 65.3-89.5%; I-2 = 90.0%) for PET/CT. The study location and the use of predefined imaging criteria for liver metastasis were associated with PET/MRI study heterogeneity. Conclusion [(68) Ga]Ga-DOTA-SSA PET/MRI had good overall performance for detecting liver metastasis in patients with NET. Because of the small number of eligible studies, further studies are needed to validate the clinical usefulness of [(68) Ga]Ga-DOTA-SSA PET/MRI.