Serial measurement of hepatic lipids during chemotherapy in patients with colorectal cancer: a 1 H MRS study

Study of lipid metabolism by estimating the fat fraction in different breast tissues and in various breast tumor sub-types by in vivo 1H MR spectroscopy

PURPOSE

To evaluate the utility of fat fraction (FF) for the differentiation of different breast tissues and in various breast tumor subtypes using in vivo proton (¹H) magnetic resonance spectroscopy (MRS).

METHODS

¹H MRS was performed on 68 malignant, 35 benign, and 30 healthy volunteers at 1.5 T. Malignant breast tissues of patients were characterized into different subtypes based on the differences in the expression of hormone receptors and the FF was calculated. Further, the sensitivity and specificity of FF to differentiate malignant from benign and from normal breast tissues of healthy volunteers was determined using receiver operator curve (ROC) analysis.

RESULTS

A significantly lower FF of malignant (median 0.12; range 0.01-0.70) compared to benign lesions (median 0.28; range 0.02-0.71) and normal breast tissue of healthy volunteers (median 0.39; range 0.06-0.76) was observed. No significant difference in FF was seen between benign lesions and normal breast tissues of healthy volunteers. Sensitivity and specificity of 75% and 68.6%, respectively was obtained to differentiate malignant from benign lesions. For the differentiation of malignant from healthy breast tissues, 76% sensitivity and 74.5% specificity was achieved. Higher FF was seen in patients with ER-/PR- status as compared to ER+/PR+ patients. Similarly, FF of HER2neu+ tumors were significantly higher than in HER2neu- breast tumors.

CONCLUSION

The results showed the potential of in vivo ¹H MRS in providing insight into the changes in the fat content of different types of breast tissues and in various breast tumor subtypes.

Improved quantitative fatty acid values with correction of T2 relaxation time in terminal methyl group: In vivo proton magnetic resonance spectroscopy at ultra high field in hepatic steatosis

Proton magnetic resonance spectroscopy (MRS) with optimized relaxation time is an effective method to quantify hepatic fatty acid values and characterize steatosis. The aim of this study is to quantify the difference in hepatic lipid content with metabolic changes during the progression of steatosis by using localized MRS sequence with T₂ relaxation time determination. Fatty liver disease was induced in C57BL/6N mice through a high-fat diet (HFD) of pellets containing 60% fat, 20% protein, and 20% carbohydrates. We used stimulated echo acquisition mode (repetition time: 3500 ms; mixing time: 10 ms; echo time: 20 ms) sequence. Using enhanced and mono exponential curve-fitting methods, the lipid relaxation time in mice was estimated at a fixed repetition time of 5000 ms and echo time ranging from 20 to 70 ms. The calculated lipid contents with incorrect and correct relaxation times were as follows: total saturated fatty acid (4.00 ± 2.90 vs 6.74 ± 2.25, p < 0.05 at week 0; 15.23 ± 9.94 vs 25.53 ± 10.49, p < 0.05 at week 4); total unsaturated fatty acid (0.40 ± 0.49 vs 0.56 ± 0.47, p < 0.05 at week 4; 0.33 ± 0.26 vs 0.60 ± 0.21, p < 0.01 at week 7); total unsaturated bond (0.48 ± 0.52 vs 1.05 ± 0.58, p < 0.05 at week 10). Furthermore, we determined that the correct relaxation times of triglycerides between 0 and 10 weeks were significantly altered in the resonances (∼2.03 ppm: 31.07 ± 1.00 vs 27.62 ± 1.20, p < 0.01; ∼2.25 ppm: 29.10 ± 1.52 vs 26.39 ± 1.08, p < 0.05; ∼2.78 ppm: 37.67 ± 2.92 vs 29.37 ± 2.64, p < 0.001). The work presented focused on the significance of the J-coupling effect. The selection of an appropriate relaxation time considering the J-coupling effect provides an effective method for quantifying lipid contents and characterizing hepatic steatosis.

Effect of J coupling on 1.3-ppm lipid methylene signal acquired with localised proton MRS at 3 T

The purpose of this work was to investigate the effect of J-coupling interactions on the quantification and T2 determination of 1.3-ppm lipid methylene protons at 3 T. The response of the 1.3-ppm protons of hexanoic, heptanoic, octanoic, linoleic and oleic acid was measured as a function of point-resolved spectroscopy (PRESS) and stimulated echo acquisition mode (STEAM) TE. In addition, a narrow-bandwidth refocusing PRESS sequence designed to rewind J-coupling evolution of the 1.3-ppm protons was applied to the five fatty acids, to corn oil and to tibial bone marrow of six healthy volunteers. Peak areas were plotted as a function of TE, and data were fitted to monoexponentially decaying functions to determine Mo (the extrapolated area for TE = 0 ms) and T2 values. In phantoms, rewinding J-coupling evolution resulted in 198%, 64%, 44%, 20% and 15% higher T2 values for heptanoic, octanoic, linoleic and oleic acid, and corn oil, respectively, compared with those obtained with standard PRESS. The narrow-bandwidth PRESS sequence also resulted in significant changes in Mo , namely -77%, -22%, 28%, 23% and 28% for heptanoic, octanoic, linoleic and oleic acid, and corn oil, respectively. T2 values obtained with STEAM were closer to the values measured with narrow-bandwidth PRESS. On average, in tibial bone marrow (six volunteers) rewinding J-coupling evolution resulted in 21% ± 3% and 9 % ± 1% higher Mo and T2 values, respectively. This work demonstrates that the consequence of neglecting to consider scalar coupling effects on the quantification of 1.3-ppm lipid methylene protons and their T2 values is not negligible. The linoleic and oleic acid T2 results indicate that T2 measures of lipids with standard MRS techniques are dependent on lipid composition.

Abdominal visceral and subcutaneous fat increase, insulin resistance and hyperlipidemia in testicular cancer patients treated with cisplatin-based chemotherapy

BACKGROUND

Testicular cancer survivors treated with chemotherapy are at increased risk for metabolic syndrome (MetS) and cardiovascular disease (CVD). We explored acute effects of chemotherapy by assessing metabolic factors, abdominal fat volume, hepatic triglyceride content (HTC) and aortic wall stiffness.

MATERIAL AND METHODS

We studied 19 testicular cancer patients (age 20-54 years) before, at three and nine months after the start of chemotherapy. Blood serum was analyzed for lipids, glucose and insulin. Abdominal visceral and subcutaneous fat volume and aortic pulse wave velocity were assessed by magnetic resonance imaging (MRI) techniques; HTC was measured by proton MR spectroscopy.

RESULTS

Three months after start of chemotherapy visceral abdominal fat volume had significantly increased from 202 ± 141 to 237 ± 153 ml (p = 0.009) whereas body mass index and subcutaneous fat volume significantly increased nine months after treatment from 24.4 ± 4.0 to 26.4 ± 4.1 kg/m(2) (p = 0.01) and from 556 ± 394 to 668 ± 460 ml (p = 0.002) respectively. Serum total cholesterol, low-density lipoprotein cholesterol and insulin also significantly increased three months after start of treatment from 4.88 ± 1.1 to 5.61 ± 1.50 mmol/l (p = 0.002), 3.31 ± 1.16 to 3.73 ± 1.41 mmol/l (p = 0.02) and 5.7 ± 4.4 to 9.6 ± 6.3 mU/ml (p = 0.03), respectively. Nine months after start of chemotherapy serum lipid and insulin concentrations had returned to baseline. HTC increased in seven of the 19 patients (36.8%) during follow-up. Aortic pulse wave velocity remained unchanged at the three time points measured.

CONCLUSION

Cisplatin-based chemotherapy was associated with acute insulin resistance, dyslipidemia and an immediate increase in abdominal visceral adipose tissue and abdominal subcutaneous adipose tissue in testicular cancer patients. A large prospective cohort study with long follow-up is warranted to characterize the time course and relationship between acutely induced obesity and hypercholesterolemia and the development of metabolic syndrome and CVD years later in individual testicular cancer survivors.