Techniques

Our research focuses on the use of sophisticated imaging and processing techniques to probe metabolic and biochemical features of human tissues. Some of the techniques we use include:

Magnetic Resonance Imaging (MRI)

MR imaging techniques are available for researchers requiring high-resolution imaging of joints and soft tissues. We have expertise in design and implementation of imaging protocols, as well as close supervision during data acquisition.

We work closely with investigators in order to modify or develop MRI acquisition protocols that address specific clinical endpoints. These methods include:

  • cartilage relaxometry measures using T2, T2* and T1rho
  • high-resolution cartilage imaging for 3D modeling and simulations
  • high-resolution bone imaging for 3D reconstructions
3D SPGR 1-mm thick images of ankle (A) and knee (B) used for 3-dimensional reconstruction of cartilage surfaces.

3D SPGR 1-mm thick images of ankle (A) and knee (B) used for 3-dimensional reconstruction of cartilage surfaces.

Magnetic Resonance Spectroscopy (MRS)

1H-MRS allows non-invasive quantification of muscle metabolites, such as lipids, total creatine, and choline. Using this methodology, we’re capable of differentiating and selectively measuring lipids located inside or in between muscle cells. This technique has been widely employed in studies investigating mechanisms of insulin sensitivity in type 2 diabetics, obese and HIV-lipodystrophy patients.

We acquire 1H-MRS data using GE and Siemens scanners at 1.5T or 3.0T field strengths, and perform analyses with softwares such as LCModel, iNMR and jMRUI.

We can modify or develop MRS acquisition protocols in order to address your specific clinical endpoint.

Proton MRS spectrum of tibialis anterior muscle with peak fitting using LCModel (dark trace, fitted spectrum; thin trace, raw data; thin trace in top of figure, residual). [1] IMCL (-CH3), intramyocellular lipid methyl protons at 0.9 ppm [2] EMCL (-CH3), extramyocellular lipid methyl protons at 1.1 ppm [3] IMCL (-CH2), intramyocellular lipid methylene protons at 1.3 ppm [4] EMCL (-CH2), extramyocellular lipid methylene protons at 1.5 ppm [5] TCr, total creatine (-CH3) resonance at 3.0 ppm [6] TMA, trimethylamines, choline peak at 3.2 ppm

Proton MRS spectrum of tibialis anterior muscle with peak fitting using LCModel (dark trace, fitted spectrum; thin trace, raw data; thin trace in top of figure, residual).
[1] IMCL (-CH3), intramyocellular lipid methyl protons at 0.9 ppm, [2] EMCL (-CH3), extramyocellular lipid methyl protons at 1.1 ppm, [3] IMCL (-CH2), intramyocellular lipid methylene protons at 1.3 ppm, [4] EMCL (-CH2), extramyocellular lipid methylene protons at 1.5 ppm
[5] TCr, total creatine (-CH3) resonance at 3.0 ppm,
[6] TMA, trimethylamines, choline peak at 3.2 ppm

Quantitative Computed Tomography (QCT)

QCT is a powerful method for assessment of body composition and bone mineral density (BMD).

Body composition

Using a single slice of the abdomen obtained at L4, a variety of adipose tissue compartments can be measured while keeping radiation exposure to a minimum. Standard measurements obtained using dedicated software include:

  • Intra-abdominal (visceral) fat area
  • Subcutaneous fat area
  • Total adipose tissue area
  • Total cross-sectional area
Single slice of abdomen obtained at L4, showing tracings for total abdominal area (red), abdominal subcutaneous fat area (tissue between red and yellow), and visceral fat (green).

Single slice of abdomen obtained at L4, showing tracings for total abdominal area (red), abdominal subcutaneous fat area (tissue between red and yellow), and visceral fat (green).

Bone mineral density

QCT is widely employed for determination of bone mineral density (BMD) of the lumbar spine. This methodology bypasses certain limitations of DXA planar acquisitions, and allows reliable estimates of BMD. We obtain CT slices at 4 lumbar levels and measure vertebral body density calibrated by a standard phantom.

CT slice showing measurement of attenuation values of vertebral body and standardized K2PO4 phantom for BMD determination.

CT slice showing measurement of attenuation values of vertebral body and standardized K2PO4 phantom for BMD determination.

We can modify or develop QCT protocols and measurement methodology in order to address your specific clinical endpoint.

If you have any questions about metabolic imaging techniques, please contact us.