Computed tomography-based assessment of abdominal adiposity changes and their impact on metabolic alterations following bariatric surgery.

BACKGROUND: The aim of this study was to evaluate the effects of surgically induced weight loss on the abdominal adipose tissue depots and the metabolic profile in morbidly obese (MO) patients. METHODS: The study was performed with a semi-automated quantification of adipose tissue compartments on single-slice abdominal CT series before surgery, 6 and 12 months after bariatric surgery. Thirty-eight MO patients with mean age of 35.7 ± 10.1 years and mean body mass index (BMI) of 43.6 ± 6.5 kg/m(2) were studied (20 patients underwent gastric banding and 18 patients underwent sleeve gastrectomy). Anthropometric measurements, metabolic and inflammatory parameters were analyzed in each patient. RESULTS: Markedly decreased levels of total abdominal adipose tissue, abdominal subcutaneous adipose tissue (AbSAT) and visceral adipose tissue (VAT) at 6 and 12 months were noted in comparison to the preoperative values. The total % reduction of VAT was significant higher in comparison to the total % reduction of AbSAT at 12 months after bariatric surgery (P < 0.01) with the mean ratio of AbSAT/VAT to increase from 4.1 ± 1.7 preoperatively to 6.2 ± 3.1 at 12 months postoperatively (P < 0.001). In addition, high-sensitivity C-reactive protein (hsCRP) decreased significantly with weight loss after bariatric surgery and the total abdominal lipid loss was related to the decrease in hsCRP. CONCLUSIONS: Significant changes in abdominal lipid deposition occurred in MO patients 6 and 12 months after bariatric surgery. The changes were significantly, correlated with the magnitude of BMI loss. The fat redistribution may contribute to the improvements in metabolic abnormalities.

Diagnostic performance of whole brain volume perfusion CT in intra-axial brain tumors: preoperative classification accuracy and histopathologic correlation.

BACKGROUND: To evaluate the preoperative diagnostic power and classification accuracy of perfusion parameters derived from whole brain volume perfusion CT (VPCT) in patients with cerebral tumors. METHODS: Sixty-three patients (31 male, 32 female; mean age 55.6 ± 13.9 years), with MRI findings suspected of cerebral lesions, underwent VPCT. Two readers independently evaluated VPCT data. Volumes of interest (VOIs) were marked circumscript around the tumor according to maximum intensity projection volumes, and then mapped automatically onto the cerebral blood volume (CBV), flow (CBF) and permeability Ktrans perfusion datasets. A second VOI was placed in the contra lateral cortex, as control. Correlations among perfusion values, tumor grade, cerebral hemisphere and VOIs were evaluated. Moreover, the diagnostic power of VPCT parameters, by means of positive and negative predictive value, was analyzed. RESULTS: Our cohort included 32 high-grade gliomas WHO III/IV, 18 low-grade I/II, 6 primary cerebral lymphomas, 4 metastases and 3 tumor-like lesions. Ktrans demonstrated the highest sensitivity, specificity and positive predictive value, with a cut-off point of 2.21 mL/100mL/min, for both the comparisons between high-grade versus low-grade and low-grade versus primary cerebral lymphomas. However, for the differentiation between high-grade and primary cerebral lymphomas, CBF and CBV proved to have 100% specificity and 100% positive predictive value, identifying preoperatively all the histopathologically proven high-grade gliomas. CONCLUSION: Volumetric perfusion data enable the hemodynamic assessment of the entire tumor extent and provide a method of preoperative differentiation among intra-axial cerebral tumors with promising diagnostic accuracy.

Brain volume perfusion CT performed with 128-detector row CT system in patients with cerebral gliomas: a feasibility study.

OBJECTIVES: Validation of the feasibility and efficacy of volume perfusion computed tomography (VPCT) in the preoperative assessment of cerebral gliomas by applying a 128-slice CT covering the entire tumour. METHODS: Forty-six patients (25 men, 21 women; mean age 52.8 years) with cerebral gliomas were evaluated with VPCT. Two readers independently evaluated VPCT data, drawing volumes of interest (VOIs) around the tumour according to maximum intensity projection volumes, which were mapped automatically onto the cerebral blood volume (CBV), flow (CBF) and permeability (Ktrans) perfusion datasets. As control, a second VOI was placed in the contralateral healthy cortex. Correlation among perfusion parameters, tumour grade, hemisphere and VOIs was assessed. The diagnostic power of perfusion parameters was analysed by receiver operating characteristics curve analyses. RESULTS: VPCT was feasible in the assessment of the entire tumour extent. Mean values of Ktrans, CBV, CBF in high-grade gliomas were significantly higher compared with low-grade (p < 0.01). Ktrans demonstrated the highest diagnostic (97% sensitivity), positive (100%) and negative (94%) prognostic values. CONCLUSIONS: VPCT was feasible in all subjects. All areas of different perfusion characteristics are depicted and quantified in colour-coded 3D maps. The derived parameters correlate well with tumour histopathology, differentiating low- from high-grade gliomas.

Dynamic CT perfusion imaging of intra-axial brain tumours: differentiation of high-grade gliomas from primary CNS lymphomas.

INTRODUCTION: Perfusion computed tomography (PCT) allows to quantitatively assess haemodynamic characteristics of brain tissue. We investigated if different brain tumor types can be distinguished from each other using Patlak analysis of PCT data. METHODS: PCT data from 43 patients with brain tumours were analysed with a commercial implementation of the Patlak method. Four patients had low-grade glioma (WHO II), 31 patients had glioblastoma (WHO IV) and eight patients had intracerebral lymphoma. Tumour regions of interest (ROIs) were drawn in a morphological image and automatically transferred to maps of cerebral blood flow (CBF), cerebral blood volume (CBV) and permeability (K (Trans)). Mean values were calculated, group differences were tested using Wilcoxon and Mann Whitney U-tests. RESULTS: In comparison with normal parenchyma, low-grade gliomas showed no significant difference of perfusion parameters (p > 0.05) , whereas high-grade gliomas demonstrated significantly higher values (p < 0.0001 for K (Trans), p < 0.0001 for CBV and p = 0.0002 for CBF). Lymphomas displayed significantly increased mean K(Trans) values compared with unaffected cerebral parenchyma (p = 0.0078) but no elevation of CBV. High-grade gliomas show significant higher CBV values than lymphomas (p = 0.0078). DISCUSSION: PCT allows to reliably classify gliomas and lymphomas based on quantitative measurements of CBV and K (Trans).