Quantitative magnetic resonance imaging of vertebral bodies: A T1 and T2 study

Quantitative analysis of diurnal variation in volume and water content of lumbar intervertebral discs

“…The problem of using Region Of Interest (ROI) cursors to measure relaxation times to describe the average properties of regions of heterogeneous tissue has been highlighted by Jenkins et al (1989). Boos et al (1993) and LeBlanc et al (1994) used an ROI cursor to obtain the mean T2-relaxation time for the nucleus pulposus and annulus fibrosus taken together.…”

Detection of bone marrow abnormalities in patients with Hodgkin's disease by T1 mapping of MR images of lumbar vertebral bone marrow

“…Conventional spin echo MR imaging has been shown to be of value in detecting marrow infiltration in lymphoma and small cell lung cancer, but this relies on the subjective interpretation of often subtle alterations in signal intensity patterns (Linden et relaxation times using region of interest cursors show promise (Richards et al, 1988;Smith et al, 1989b), but suffer from the limitations associated with the use of such cursors (Jenkins et al, 1989). The Ti mapping procedures used in the present study offer several advantages over region of interest cursor methods.…”

“…In addition, studies using region of interest cursors have revealed that an increased variation in TI throughout the lumbar vertebral bone marrow may indicate underlying pathology, by reflecting focal marrow infiltration and marrow heterogeneity . Relaxation time measurements obtained with region of interest cursors are however subject to limitations, especially when the tissues being examined are known to be heterogeneous (Jenkins et al, 1989).…”

Quantification of bone healing: Comparison of QCT, SPA, MRI, and DEXA in dog osteotomies

“…First, MR is only indirectly proportional to mineral density so would not be expected to have high correlations with calcium content (Nixon 1987). Second, M R has only rarely and unsuccessfully been used as a quantitative method; Jenkins et al (1989) measured TI and T, relaxation times of vertebral bodies and could not distinguish between age, sex, or location in the spine. The technique's potential sources of error are many and include: 1) positioning of the region of interest, since large errors can result from small changes in position (Jenkins et al 1989); 2 ) slice thickness limitations of 5 mm in this study; 3) edge effects at interfaces between low and high signal intensity, such as cortical bone and endosteal callus (Clark and Kelly 1988); 4) chemical shift between interfaces of fat-bound protons bordering hydrated tissues such as endosteal callus and trabecular bone; 5) focal field inhomogeneity from irregularly deposited calcium within the callus; 6) volume averaging of two opposing tissue planes with markedly different signal characteristics such as cortical bone and periosteal or endosteal callus; and 7) pulse imperfections of the hardware (Majumdar et al 1986).…”

“…A lucite calibration phantom was used to quantitate intensity values for the three different imaging techniques and to increase the inherent accuracy and repeatability of scanning (Jenkins et al 1989). The phantom was curved to conform to the head coil of the scanner.…”