Eun Kee Jeong

Correlation of laminated MR appearance of articular cartilage with histology, ascertained by artificial landmarks on the cartilage †

The object of this study was to correlate the laminae of articular cartilage on magnetic resonance (MR) imaging with histologic layers. T1‐ and fast spin‐echo T2‐weighted images of articular cartilage with artificial landmarks were obtained under high gradient echo strength (25 mT/m) conditions and a voxel size of 78 × 156 × 2000 μm. Images were also obtained with a) changed frequency‐encoding directions; b) changed readout gradient strength; and c) a varied number of phase‐encoding steps. T2 mapping was performed with angular variations. Artificial landmarks allowed accurate comparison between the laminae on MR images and the histologic zones. No alterations of the laminae were noted by changing the frequency gradient direction. Altering readout gradient strengths did not show a difference in the thickness of the laminae, and increasing the phase‐encoding steps resulted in a more distinct laminated appearance, ruling out chemical shift, susceptibility, and truncation artifacts. The T2 mapping profile showed an anisotropic angular dependency from the magic angle effect. In conclusion, the laminated appearance of articular cartilage on spin‐echo and fast spin‐echo MR images correlated with the histologic zones rather than MR artifacts.J. Magn. Reson. Imaging 1999;10:57–64.

Role of the inflamed synovial volume of the wrist in defining remission of rheumatoid arthritis with gadolinium-enhanced 3D-SPGR MR imaging

The purpose of this study was to assess the role of inflamed synovial volume (ISV) in defining a state of remission in rheumatoid arthritis (RA) with contrast‐enhanced, fat‐suppression, three‐dimensional (3D) gradient‐recalled acquisition in the steady state with radiofrequency spoiling (SPGR) magnetic resonance (MR) imaging. Sixteen patients with RA (5 remission and 11 non‐remission patients) were enrolled in this study. Contrast‐enhanced, fat‐suppression, 3D‐SPGR MR imaging was performed before (n = 12) and after (n = 16) a mean 17 months of disease‐modifying antirheumatic drugs (DMARDs). ISV was calculated by using a segmentation method. Statistical analysis of changes in ISVs and residual ISVs between the remission and the non‐remission groups was performed. Intra‐ and inter‐observer reproducibility was tested. Residual ISVs and relative changes in ISVs were 3.23 ± 1.84 cm3 and 51.4% (range 47.6–55.2%) in the remission group and 6.26 ± 2.03 cm3and 31.4% (range ‐73.5–53.5%) in the non‐remission group. Both values were significantly different between the two groups (P < 0.05 and 0.05, respectively). Volume measurement showed high reproducibility: Intra‐ and inter‐observer mean percentage errors were 5.04, 7.06, and 5.09%, respectively. Residual ISVs and relative changes in ISVs measured by MR imaging may provide objective and quantitative parameters in defining a state of remission in RA after therapy; however, the clinical utility of these measurements remains to be verified. J. Magn. Reson. Imaging 1999;10:202–208.

Hepatic MRI Using the Double-Echo Chemical Shift Phase-Selective Gradient-Echo Technique

OBJECTIVE The objective of our study was to describe the merits and drawbacks of the double-echo chemical shift phase-selective gradient-echo technique for hepatic MRI. CONCLUSION With complementary information from two different dynamic imaging sets in conjunction with errorless subtraction between in- and out-of-phase images, the double-echo chemical shift phase-selective gradient-echo technique provides useful information regarding unpredictable variations in intra- or extralesional lipid content, allowing detailed assessment of focal lesions during hepatic MRI.

High-Resolution Diffusion-Weighted Imaging of Neck Lymph Nodes Using 2D-Single-Shot Interleaved Multiple Inner Volume Imaging Diffusion-Weighted Echo-Planar Imaging at 3T

BACKGROUND AND PURPOSE: 2D-ss-IMIV-DWEPI is an ss-DWEPI with greatly reduced geometric distortion. The purposes of this paper are to 1) evaluate of the utility of 2D-ss-IMIV-DWEPI for high-resolution neck LN imaging; 2) determine whether 2D-ss-IMIV-DWEPI can depict normal LN hilum; and 3) evaluate whether the inclusion of LN hilum within ROIs affects the measured LN ADC. MATERIALS AND METHODS: HR-DWI was acquired with 1-mm2 in-plane resolution and 2-mm section thickness by using 2D-ss-IMIV-DWEPI. In total, 58 LNs from 18 subjects were evaluated. The ADC map was calculated by using DWI with b = 10 and 300 s/mm2. In those LNs where the LN hilum could be recognized, the LN ADC was measured with and without inclusion of the hilum, and the mean difference of the resulting ADC values was determined. RESULTS: The hilar structure was identified by DWI in 15 LNs. The ADC of the hilum was 1.981 ± 0.331 × 10−3 mm2/s. In these 15 LNs, the ADC value excluding hilar structure was significantly lower than the ADC value including hilar structure (0.983 ± 0.169 versus 1.206 ± 0.244 × 10−3 mm2/s; P < .0001). The mean ADC in a total of 58 LNs excluding the hilar structure was significantly lower than the value obtained including the hilar structure (1.034 ± 0.183 versus 1.095 ± 0.213 × 10−3 mm2/s; P = .0002). CONCLUSIONS: HR-DWI of neck LNs obtained by using 2D-ss-IMIV-DWEPI could identify the hilar structure. The ADC of normal neck LNs seemed significantly different when the hilum was included. The results suggest that HR-DWI may be helpful to aid selection of proper ROIs within LNs for accurate and reliable ADC measurements.