Study Design Prospective MRI study of LBP patients requiring discography as part of their routine clinical diagnoses and asymptomatic age-matched volunteers. Objective To determine whether T1ρ MRI and discography opening pressure are quantitative biomarkers of disc degeneration in LBP patients and in asymptomatic volunteers. Summary of Background Data Disc degenerative disease (DDD), a common cause of low back pain (LBP), is related to the patient’s prognosis and serves as a target for therapeutic interventions. However, there are few quantitative measures in the clinical setting. Discography opening pressure (OP) and T1ρ MRI are potential biomarkers of DDD related to biochemical composition the intervertebral disc (IVD). Methods The Institutional Review Board approved all experiments and informed consent was provided by each subject. Patients being treated for LBP (n=17, 68 levels, mean age 44±6 years, range 30–53) and control (CTL) subjects (n=11, 44 levels, mean age 43±17, range 22–76) underwent T1ρ and T2 MRI on a Siemens 3T Tim Trio clinical scanner. The LBP patients also received multi-level provocative discography before their MRI. Opening Pressure (OP) was recorded as the pressure when fluid first enters the nucleus of the IVD. Results T1ρ was significantly lower in the painful discs (55.3ms±3.0 ms, mean ± std. error) from control (92.0±4.9 ms, p<0.001) and non-painful discs (83.6±3.2 ms, p<0.001). Mean OP for the painful discs (11.8±1.0 psi, mean ± std. error) was significantly lower than non-painful discs (19.1±0.7 psi, p<0.001). Both T1ρ and OP correlated moderately with Pfirrmann degenerative grade. ROC area under the curve was 0.91 for T1ρ MRI and 0.84 for OP for predicting painful discs. Conclusions T1ρ and OP are quantitative measures of degeneration that are consistent across both control subjects and LBP patients. A significant and strong correlation exists between T1ρ values and in vivo OP measurements obtained by discography in LBP patients.

Purpose:To evaluate the T1rho (T 1 ) MRI relaxation time in hippocampus in the brain of Alzheimer's disease (AD), mild cognitive impairment (MCI), and control, and to determine whether the T 1 shows any significant difference between these cohorts. Materials and Methods:With informed consent, AD (n ϭ 49), MCI (n ϭ 48), and age-matched control (n ϭ 31) underwent T 1 MRI on a Siemens 1.5T Scanner. T 1 values were automatically calculated from the left and right hippocampus region using in-house developed software. Bonferroni post-hoc multiple comparisons was performed to compare the T 1 value among the different cohorts.Results: Significantly higher T 1 values were observed both in AD (P ϭ 0.000) and MCI (P ϭ 0.037) cohorts compared to control; also, the T 1 in AD was significantly high over (P ϭ 0.032) MCI. Hippocampus T 1 was 13% greater in the AD patients than control, while in MCI it was 7% greater than control. Hippocampus T 1 in AD patients was 6% greater than MCI. Conclusion:Higher hippocampus T 1 values in the AD patients might be associated with the increased plaques burden. A follow-up study would help to determine the efficacy of T 1 values as a predictor of developing AD in the control and MCI individuals.

Purpose: To develop a T1-prepared, balanced gradient echo (b-GRE) pulse sequence for rapid three-dimensional (3D) T1 relaxation mapping within the time constraints of a clinical exam (Ͻ10 minutes), examine the effect of acquisition on the measured T1 relaxation time and optimize 3D T1 pulse sequences for the knee joint and spine. Materials and Methods:A pulse sequence consisting of inversion recovery-prepared, fat saturation, T1-preparation, and b-GRE image acquisition was used to obtain 3D volume coverage of the patellofemoral and tibiofemoral cartilage and lower lumbar spine. Multiple T1-weighted images at various contrast times (spin-lock pulse duration [TSL]) were used to construct a T1 relaxation map in both phantoms and in the knee joint and spine in vivo. The transient signal decay during b-GRE image acquisition was corrected using a k-space filter. The T1-prepared b-GRE sequence was compared to a standard T1-prepared spin echo (SE) sequence and pulse sequence parameters were optimized numerically using the Bloch equations. Results:The b-GRE transient signal decay was found to depend on the initial T1-preparation and the corresponding T1 map was altered by variations in the point spread function with TSL. In a two compartment phantom, the steady state response was found to elevate T1 from 91.4 Ϯ 6.5 to 293.8 Ϯ 31 and 66.9 Ϯ 3.5 to 661 Ϯ 207 with no change in the goodness-of-fit parameter R 2 . Phase encoding along the longest cartilage dimension and a transient signal decay k-space filter retained T1 contrast. Measurement of T1 using the T1-prepared b-GRE sequence matches standard T1-prepared SE in the medial patellar and lateral patellar cartilage compartments. T1-preparedb-GRE T1 was found to have low interscan variability between four separate scans. Mean patellar cartilage T1 was elevated compared to femoral and tibial cartilage T1. Conclusion:The T1-prepared b-GRE acquisition rapidly and reliably accelerates T1 quantification of tissues offset partially by a TSL-dependent point spread function. CONVENTIONAL CONTRAST in magnetic resonance (MR) images derives from the 1 H magnetic relaxation properties of tissues. Variations in longitudinal magnetic relaxation (T1) and transverse magnetic relaxation (T2) distinguish the healthy and pathological states. An unconventional contrast mechanism based on the rotating frame spin-lattice relaxation time T1 (1) shows sensitivity to the diseased states of the human breast (2), early acute cerebral ischemia in rats (3,4), knee cartilage degeneration during osteoarthritis (5), posttraumatic cartilage injury (6), and narrowing of lumbar intervertebral discs associated with degenerative disc disease (7,8). In addition, functional T1 imaging shows both an augmented blood oxygen level dependent (BOLD) signal (9,10) and improved response to indirectly detected metabolic H 2 17 O (11-13). T1-weighted contrast is produced in vivo by allowing transverse magnetization to relax in the presence of an on-resonance continuous wave (cw) radio frequency (RF) pulse and is influenc...

Study Design-This study demonstrated the diagnostic potential of sodium MRI for non-invasive quantification of PG in the intervertebral discs.Objective-To determine the existence of a linear correlation between intervertebral disc [Na] measured from sodium MRI and [PG] measurement from DMMB assay. Methods-3D sodium MRI images of bovine discs were acquired and converted into [Na] maps. Samples were systematically removed from the discs for DMMB assay. The removal locations were photographically recorded and applied to the [Na] maps to extract the [Na] measurements for comparison. In vivo sodium MRI scans were also carried out on a pair of symptomatic and asymptomatic subjects. [PG] data yielded a significant linear correlation coefficient of 0.71. The in vivo sodium MRI image of the symptomatic subject showed significant [Na] decrease when compared to that of the asymptomatic subject. Summary of Background Data-Previous Results-The linear regression fit of [Na] versusConclusion-Sodium MRI's specificity for PG in the intervertebral discs makes it a promising diagnostic tool for the earlier phase of disc degeneration.