Validity of a new automated software program for visceral adipose tissue estimation.

INTRODUCTION: Given the considerable time and research cost of analyzing biomedical images to quantify adipose tissue volumes, automated image analysis methods are highly desirable. Hippo Fat is a new software program designed to automatically quantify adipose tissue areas from magnetic resonance images without user inputs. Hippo Fat has yet to be independently validated against commonly used image analysis software programs. OBJECTIVE: Our aim was to compare estimates of VAT (visceral adipose tissue) and SAT (subcutaneous adipose tissue) using the new Hippo Fat software against those from a widely used, validated, computer-assisted manual method (slice-O-matic version 4.2, Tomovision, Montreal, CA, USA) to assess its potential utility for large-scale studies. METHODS: A Siemens Magnetom Vision 1.5-T whole-body scanner and a T1-weighted fast-spin echo pulse sequence were used to collect multiple, contiguous axial images of the abdomen from a sample of 40 healthy adults (20 men) aged 18-77 years of age, with mean body mass index of 29 kg/m(2) (range=19-43 kg/m(2)). RESULTS: Hippo Fat provided estimates of VAT and SAT that were highly correlated with estimates using slice-O-matic (R (2)>0.9). Average VAT was 9.4% lower and average SAT was 3.7% higher using Hippo Fat compared to slice-O-matic; the overestimation of SAT tended to be greater among individuals with greater adiposity. Individual-level differences for VAT were also substantial; Hippo Fattrade mark gave estimates of VAT ranging from 1184 cm(3) less to 566 cm(3) more than estimates for the same person using slice-O-matic. CONCLUSION: Hippo Fat provides a rapid method of quantifying total VAT, although the method does not provide estimates that are interchangeable with slice-O-matic at either the group (mean) or individual level.

Large arrays of spatial light modulators hybridized to silicon integrated circuits.

Large, high-frame-rate spatial light modulators are key components required for the realization of real-time optical processors. We report a 128 × 128 array of GaAs-based optical modulators that we hybridized to a Si integrated circuit by using In bump bonds to form a spatial light modulator. These optical modulators are composed of a series of quantum wells within an asymmetric Fabry-Perot cavity to control the optical properties. The resulting 128 × 128 element array operates in an intensity-only reflection mode at greater than 100,000 frames per second. This array interfaces to a 486-based personal computer through a standard industry standard architecture bus.

Silicon antiresonant reflecting optical waveguides.

A new silicon waveguide called ARROW-C is proposed and analyzed at the 1.3-microm wavelength. The silicon structure uses two buried layers of SiO(2) or beta-SiC with a thickness of 14-23 nm to permit optical tunneling for leakymode propagation. A propagation loss of ~0.5 dB/cm is predicted for the TE(0) or the TM(0) mode in a 5-microm-thick Sicore layer. Novel silicon ARROW-A and ARROW-B guides are also discussed. The former uses a pair of buried GeSi layers; the latter employs buried SiO(2) and GeSi films.