Table 2.
Overview on existing bariatric surgery studies. Studies are subdivided by neuroimaging technique. Studies may be listed more than once if more than one neuroimaging technique is applied. For the interpretation of parameters reported in columns “Modelling: Outcome”, “Predictor”, and “Significant prediction results”, please see Table 1
| Study | Modelling: Outcome | #Participants (per group) | Experimental design | Predictor | Pred. meth | Significant prediction results |
|---|---|---|---|---|---|---|
| Task-fMRI | ||||||
| Bach et al. [85] |
Prognostic: Bodyweight |
11 OB: 10 RYGB, 1 SG | T0 (2 weeks before surgery) T6.5 (24 weeks after surgery) | Voxel CR activity | OLS | CR_fMRI_T0 → OUT_T0_6.5: No association between WL and evaluated neuroimaging predictors was found |
| Smith et al. [176] |
Prognostic: Bodyweight |
39 OB: 19 RYGB, 20 SG | T0 (pre surgery), T6 (after 6 months) | Voxel CR activity | OLS | CR_fMRI_T0 → OUT_T0_6: Negative association between WL and CR activity of ventral tegmental area after RYGB (but not SG) |
| Holsen et al. [196] |
Prognostic: Bodyweight |
18 OB: SG | T0 (pre surgery), T12 (12 months after surgery) | Voxel CrvR activity | OLS | CrvR_fMRI_T0 → OUT_T0_12: Negative association between WL and upregulated CR activity in ncl. accumbens and hypothalamus |
| Ness et al. [178] |
Prognostic: Bodyweight |
19 OB: LAGB | T0 (pre surgery), T3 (3 months after surgery), T6 (6 months after surgery) | Voxel CR activity | OLS |
CR_fMRI_T0 → OUT_T0_3: Positive association between WL and CR activity in left superior frontal and transverse temporal gyrus; Negative association between WL and CR activity in right and left post. cerebellar lobe; CR_fMRI_T0 → OUT_T0_6: Positive association between WL and CR activity in right inferior temporal and frontal gyrus, right occipital cortex, left and right post. cerebellar lobe; Negative association between WL and CR activity in right cuneus, left precuneus, and left superior frontal gyrus |
| Bruce et al. [197] |
Prognostic: Eating behavior |
10 OB: LAGB | T0 (pre surgery), T3 (12 weeks after surgery) | Voxel CR activity | OLS | CR_fMRI_T0 → OUT_T0_3: Negative association between reduction in disinhibited eating behavior and CR activity in right inferior frontal gyrus |
| Hu et al. [99] |
Associations: Bodyweight |
25 OB: SG | T0 (pre surgery), T1 (1 month after surgery), T6 (6 months after surgery) | Seed-to-voxel CR FC; averaged voxel FA in tracts connecting atlas regions | OLS |
CR_fMRI_T0_1 → OUT_T0_1: Positive association between WL and changes in CR FC between right dlPFC and ACC; DTI_sMRI_T0_6 → OUT_T0_6: Positive association between WL and changes of average FA of tract connecting right dlPFC and pregenual ACC |
| Li et al. [100] |
Associations: Bodyweight |
22 OB: SG | T0 (pre surgery), T1 (1 month after surgery) | Seed-to-voxel CR FC | OLS | CR_fMRI_T0_1 → OUT_T0_1: Positive association between surgery-induced WL and surgery-induced increase in CR FC of right dlPFC and ACC |
| Zoon et al. [198] | Associations: Eating behavior | 19 OB: RYGB | T0 (pre surgery), T2 (2 months after surgery) | Voxel CR activity | OLS | CR_fMRI_T0_2 → OUT_T0_2: Negative association between surgery-related shift in food preferences from high-fat/sweet to low-energy/savory foods and surgery-related CR activity of superior parietal lobule in response to high-energy food odor and with surgery-related activity of precuneus in response to high-energy food pictures |
| Ochner et al. [177] | Associations: Food craving | 14 OB: RYGB | T0 (1 month before surgery), T2 (1 month after surgery) | Voxel CR activity | OLS | CR_fMRI_T0_2 → OUT_T0_2: Positive association between surgery-induced changes in food wanting and changes in CR activity of caudate, lentiform nucleus, middle and superior frontal gyri, inferior parietal lobule, anterior cingulate, and thalamus. Positive association between surgery-induced changes in food liking and changes in precuneus CR activity |
| Resting-state fMRI | ||||||
| Zhang et al. [130] |
Prognostic: Bodyweight |
37 OB: SG | T0 (pre surgery), T6 (after 6 months) | Principal components of RS FC between atlas regions |
TWK (CV) |
RS_fMRI_T0 → OUT_T0_18: Accuracy for classifying successful vs. non-successful WL based on RS FC of 84% |
| Cerit et al. [126] |
Prognostic: Bodyweight |
14 OB: SG | T0 (1 month before surgery), T13 (12 months after surgery) | Seed-to-voxel RS FC | OLS | RS_fMRI_T0 → OUT_T0_13: Positive association between WL and RS FC between right ncl. accumbens and left insula and between WL and RS FC between left hypothalamus and left precentral gyrus |
| Olivo et al. [131] |
Prognostic: Bodyweight |
16 OB: RYGB | T0 (1 month before surgery) T2 (1 month after surgery), T13 (12 months after surgery) | RS FC between atlas regions | OLS | RS_fMRI_T0 → OUT_T0_13: Positive association between WL and RS FC of right paracingulate gyrus and the right amygdala |
| Schmidt et al. [127] |
Associations: Bodyweight |
14 OB: RYGB | T0 (pre surgery), T8 (8 months after surgery) | Seed-to-voxel RS FC |
OLS (CV) |
RS_fMRI_T0_8 → OUT_T0_8: Association between surgery-induced body weight changes and RS FC of ventromedial PFC and ventral striatum |
| Duan et al. [112] |
Associations: Bodyweight |
16 OB: SG | T0 (pre surgery), T1 (1 month after surgery) | Voxel ALFF | OLS | RS_fMRI_T0_1 → OUT_T0_1: Positive association between surgery-induced WL and surgery-induced ALFF reduction in OFC |
| Li et al. [111] |
Associations: Bodyweight |
22 OB: SG | T0 (pre surgery), T1 (1 month after surgery) | Voxel FCD | OLS | RS_fMRI_T0_1 → OUT_T0_1: Negative association between surgery-induced WL and surgery-induced change in local FCD in vmPFC and posterior cingulate gyrus/precuneus |
| Li et al. [118] |
Associations: Bodyweight |
17 OB: SG | T0 (pre surgery), T4 (4 months after surgery) | Voxel fractional ALFF; RS FC between atlas regions | OLS |
RS_fMRI_T0_4 → OUT_T0_4: Association between body weight and fractional ALFF in reward processing and cognitive control regions comprising OFC, gyrus rectus, superior frontal gyrus, and middle frontal gyrus RS_fMRI_T0_4 → OUT_T0_4: Association between body weight and FC between reward processing and cognitive control regions comprising OFC, gyrus rectus, superior frontal gyrus, and middle frontal gyrus |
| Dong et al. [128] |
Associations: Addiction- like symptoms |
14 OB: SG | T0 (pre surgery), T6 (6 months after surgery) | RS FC between atlas regions | OLS | RS_fMRI_T0_6 → OUT_T0_6: Positive association between addiction-like obesity symptoms (e.g., continued use despite problems, tolerance, withdrawal, dependence on food) and RS FC of precuneus and putamen |
| Zhang et al. [113] |
Associations: Anxiety |
30 OB: SG | T0 (pre surgery), T1 (1 month after surgery) | Voxel ALFF | OLS | RS_fMRI_T0 _1 → OUT_T0_1: Positive association between surgery-induced WL and surgery-induced ALFF reduction in OFC |
| Saindane et al. [123] |
Associations: Cognitive functions |
8 OB: Type of surgery not described | T0 (3 to 0 months before surgery), T4.5 (0 to 6 months after surgery) | ICs extracted from RS fMRI | OLS | RS_fMRI_T0_9 → OUT_T0_9: Positive association between surgery-related changes in pattern comparison performance and surgery-related changes in RS FC of a left executive control network |
| Positron-Emission-Tomography | ||||||
| Karlsson et al. [73] | Prognostic: Bodyweight | 19 OB: 6 RYGB, 13 SG | T0 (pre surgery), T3 (3 months after surgery), T6 (6 months after surgery), T12 (12 months after surgery), T24 (24 months after surgery) | Voxel [11C] carfentanil radiotracer binding; voxel [11C]raclopride binding | OLS |
PET_T0 → OUT_T3: Negative association between body weight and μ-opioid receptor availability in amygdala, insula, ventral striatum, and putamen PET_T0 → OUT_T6 Negative association between body weight and μ-opioid receptor availability in amygdala PET_T0 → OUT_T12 Negative association between body weight and μ-opioid receptor availability in amygdala PET_T0 → OUT_T24 Negative association between body weight and μ-opioid receptor availability in amygdala and thalamus PET_T0 → OUT_T3, PET_T0 → OUT_T6, PET_T0 → OUT_T12, PET_T0 → OUT_T24: For none of the time points, an association between future body weight and D2R availability was found |
| Steele et al. [72] |
Associations: Bodyweight |
5 OB: RYGB | T0 (Pre surgery), T1.5 (4 to 6 weeks after surgery) | Voxel [11C] raclopride radiotracer binding | VIS | PET_T0_1.5 → OUT_T0_1.5: Negative association between surgery-related changes in bodyweight and surgery-related changes in D2-receptor availability |
| Structural neuroimaging | ||||||
| Tuulari et al. [142] |
Prognostic: Bodyweight |
40 OB: 19 RYGB, 21 SG | T0 (pre surgery), T6 (6 months after surgery) | Voxel GM volume; voxel WM volume | OLS |
VBM_sMRI_T0 → OUT_T0_6: Positive associations between WL and GM volume in frontotemporal, thalamic, insular, and cerebellar areas; VBM_sMRI_T0 → OUT_T0_6: Positive association between WL and WM volume in frontotemporal areas |
| Hu et al. [99] |
Associations: Bodyweight |
25 OB: SG | T0 (pre surgery), T1 (1 month after surgery), T6 (6 months after surgery) | Averaged voxel FA in tracts connecting atlas regions; Seed-to-voxel CR FC | OLS |
DTI_sMRI_T0_6 → OUT_T0_6: Positive association between WL and changes of average FA of tract connecting right dlPFC and pregenual ACC; CR_fMRI_T0_1 → OUT_T0_1: Positive association between WL and changes in CR FC between right dlPFC and ACC |
| Michaud et al. [136] |
Associations: Bodyweight |
29 OB: SG | T0 (1 month before surgery), T5 (4 months after surgery), T13 (12 months after surgery) | Voxel WM volume averaged across atlas regions | LMM | VBM_sMRI_T0_T5_T13 → OUT_T0_T5_T13: Negative association between body weight variation and WM volume in the cingulum, cerebellar peduncle, and parietopontine tract |
| Liu et al. [148] |
Associations: Bodyweight |
22 OB: SG | T0 (pre surgery), T1 (1 month after surgery) | CT aggregated across vertices in atlas regions | OLS | CT_sMRI_T0_1 → OUT_T0_1: Uncorrected negative association between WL and CT of the superior frontal gyrus |
| Rullmann et al. [137] | Associations: Bodyweight | 27 OB: RYGB | T0 (pre surgery), T6 (6 month after surgery), T12 (12 month after surgery) | Voxel GM volume | OLS |
VBM_sMRI_T0_6 → OUT_T0_6: Negative association between WL and GM volume in the hypothalamus and the left postcentral gyrus VBM_sMRI_T0_6 → OUT_T0_6: Positive association between WL and GM volume in the right lateral OFC |
ACC anterior cingulate cortex, ALFF Amplitude of low frequency fluctuations, CrvR craving regulation, CT cortical thickness, CR cue reactivity, CV cross validation, dlPFC dorsolateral prefrontal cortex, dmPFC dorsomedial prefrontal cortex, FA fractional anisotropy, FC functional connectivity, FCD functional connectivity density, fMRI – functional magnetic resonance imaging, GM grey matter, IC independent components, LAGB laparoscopic adjustable gastric banding, LMM(r) (robust) linear mixed model regression, ncl nucleus, OB obese OFC orbitofrontal cortex, OLS ordinary least square regression, OUT outcome marker, OW overweight, PET Positron-Emission-Tomography, PFC prefrontal cortex, Pred. meth Computational prediction method, RS resting-state, RYGB Roux-en-Y gastric bypass, SG sleeve gastrectomy, sMRI structural magnetic resonance imaging, TWK twin networks and k-nearest neighbor clustering, VBM voxel based morphometry, VIS visual interpretation, vmPFC ventromedial prefrontal cortex, WL weight loss, WM white matter