4 T MRI of chondrocalcinosis in combination with three-dimensional CT, radiography, and arthroscopy: a report of three cases.

OBJECTIVE: To describe 4 T MRI techniques in imaging chondrocalcinosis within the knee and examine the results together with those demonstrated using three-dimensional (3D) computed tomography, conventional radiography, and arthroscopy. DESIGN AND PATIENTS: From a larger clinical imaging study of early osteoarthritis, knee arthroscopy patients were imaged using high-field MRI and high-resolution 3D CT prior to their surgery. Retrospective review of the imaging data diagnosed three patients with chondrocalcinosis. Fat-suppressed 3D spoiled gradient (3D SPGR) and two-dimensional fat-suppressed fast spin echo (FSE) imaging was performed at 4 T. The MR images, multi-planar reformatted CT (MPR-CT) and maximum intensity projection CT (MIP-CT) images, and radiographs were examined by a musculoskeletal radiologist for the presence and location of chondrocalcinosis. The findings from arthroscopy were also included. RESULTS: MRI showed 16 sites of punctate hypointense regions from 18 articular surfaces and five of six menisci with similar signal characteristics. Both meniscal chondrocalcinosis and meniscal tears were clearly visible using the 3D SPGR sequence. Only three sites were demonstrated to have calcification using MPR-CT and MIP-CT revealed an additional three. In articular cartilage surfaces showing surface disruption, arthroscopy demonstrated 11 sites with crystal deposition. Arthroscopy also revealed five menisci with calcification present. CONCLUSION: Our preliminary findings suggest that imaging chondrocalcinosis using spoiled gradient 4 T MRI is superior and complementary to the other imaging modalities in the detection of crystal deposition in both articular cartilage and menisci.

Characterization of common carotid artery blood-flow waveforms in normal human subjects.

Knowledge of human blood-flow waveforms is required for in vitro investigations and numerical modelling. Parameters of interest include: velocity and flow waveform shapes, inter- and intra-subject variability and frequency content. We characterized the blood-velocity waveforms in the left and right common carotid arteries (CCAs) of 17 normal volunteers (24 to 34 years), analysing 3560 cardiac cycles in total. Instantaneous peak-velocity (Vpeak) measurements were obtained using pulsed-Doppler ultrasound with simultaneous collection of ECG data. An archetypal Vpeak waveform was created using velocity and timing parameters at waveform feature points. We report the following timing (post-R-wave) and peak-velocity parameters: cardiac interbeat interval (T(RR)) = 0.917 s (intra-subject standard deviation = +/- 0.045 s); cycle-averaged peak-velocity (V(CYC)) = 38.8 cm s(-1) (+/-1.5 cm s(-1)); maximum systolic Vpeak = 108.2 cm s(-1) (+/-3.8 cm s(-1)) at 0.152 s (+/-0.008 s); dicrotic notch Vpeak = 19.4 cm s(-1) (+/-2.9 cm s(-1)) at 0.398 s (+/-0.007 s). Frequency components below 12 Hz constituted 95% of the amplitude spectrum. Flow waveforms were computed from Vpeak by analytical solution of Womersley flow conditions (derived mean flow = 6.0 ml s(-1)). We propose that realistic, pseudo-random flow waveform sequences can be generated for experimental studies by varying, from cycle to cycle, only T(RR) and V(CYC) of a single archetypal waveform.

Gadolinium-DTPA enhanced MRI demonstrates uterine vascular changes associated with artificially induced decidualization and ovoimplantation in rats.

Gadolinium-DTPA enhanced magnetic resonance (MR) imaging has been used to demonstrate uterine vascular changes during ovoimplantation and artificially induced decidualization in rats. Evans blue dye and Gd-DTPA were injected i.v. into rats 10 h after unilateral decidualization was induced by injection of sesame oil into the lumen of one uterine horn. Animals were killed various times later and uteri were removed, T1-weighted proton imaging was performed, and mean image intensities for stimulated and control uterine horns were calculated by computer-assisted image analysis. Macroscopic bluing confined to stimulated horns was apparent 5 min after tracer injection and increased in intensity until the experiment was terminated at 320 min. Analysis of MR images showed that mean image intensity of control horns did not change significantly at any time after injection of the Gd-DTPA and Evans blue whereas mean image intensity of stimulated horns increased significantly by 5 min after injection, peaked at 20 min, and returned to values not different from controls by 320 min. T1-weighted images of day 6 pregnant rats injected with Gd-DTPA and Evans blue revealed patterns of image enhancement that matched those of macroscopic bluing. Uterine concentrations of radioactivity after injection of 153Gd-DTPA indicated that increased extracellular fluid volume (ECFV) produces the image enhancement of stimulated horns since the tracer permeates the extracellular fluid of both horns. Gd-DTPA-enhanced MR imaging of uteri after deciduogenic stimulation revealed significant image enhancement for stimulated horns at both 9 and 27 h after stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)