ABSTRACT
<p><b>OBJECTIVE</b>To estimate zonal variation of GAG content in reparative cartilage after matrix associated autologous chondrocyte implantation (MACI) using delayed gadolinium-enhanced magnetic resonance imaging of the cartilage (dGEMRIC).</p><p><b>METHODS</b>Seven patients (14 cartilage defects) undergoing MACI were recruited for examination with dGEMRIC at 3, 6, and 12 months after the procedure to calculate global and zonal longitudinal relaxivity (Δ R1) of the normal cartilage and reparative cartilage.</p><p><b>RESULTS</b>The mean Δ R1 values of normal cartilage were significantly lower than those of reparative cartilage after MACI. A significant decrease was noted in the mean Δ R1 values from the deep layer to the superficial layer in the reparative cartilage at the 3 examinations. The Δ R1 values of the reparative cartilage showed no significant variation between 3 months and 6 months, but a significant decrease in the Δ R1 values occurred at 12 months.</p><p><b>CONCLUSIONS</b>dGEMRIC is feasible to assess cartilage repair noninvasively following MACI.</p>
Subject(s)
Humans , Cartilage , Pathology , Chondrocytes , Transplantation , Gadolinium , Magnetic Resonance Imaging , Orthopedic ProceduresABSTRACT
<p><b>OBJECTIVE</b>To assess the value of magnetic resonance imaging (MRI) T2 mapping in quantitative evaluation of cartilage repair following matrix-associated autologous chondrocyte transplantation (MACT).</p><p><b>METHODS</b>Six patients (with 9 plug cartilages) following MACT underwent MRI on a 3.0 Tesla MR scan system at 3, 6 and 12 months after the surgery. The full-thickness and zonal areas (deep and superficial layers) T2 values were calculated for the repaired cartilage and control cartilage.</p><p><b>RESULTS</b>The mean T2 values of the repaired cartilage after MACT were significantly higher than that of the control cartilages at 3 and 6 months (P<0.05), but not at 12 months (P=0.063). At 6 and 12 months, the T2 values of the superficial layers were significantly higher than those of the deep layers in the repaired cartilages (P<0.05). The zonal (deep and superficial layers) T2 values of the repaired cartilages decreased significantly over time at 6 and 12 months as compared to those at 3 months after the surgery (P<0.05).</p><p><b>CONCLUSION</b>MRI T2 mapping can serve as an important modality for assessing the repair of the articular cartilage following MACT.</p>
Subject(s)
Humans , Cartilage, Articular , Pathology , Chondrocytes , Transplantation , Magnetic Resonance Imaging , Transplantation, AutologousABSTRACT
<p><b>OBJECTIVE</b>To evaluate the value of T2 mapping in monitoring the repaired cartilage after matrix-associated autologous chondrocyte implantation/transplantation (MACI/MACT).</p><p><b>METHODS</b>Four patients (10 plug cartilages) were examined three times by T2 mapping at 1, 3, and 6 months using a 3.0 Tesla MR scan system. Quantitative mean (full-thickness) T2 values were calculated in the transplanted area and control cartilage. Paired t-tests were used to compare the T2 values between transplanted and control cartilage. For analysis of longitudinal T2 values, one-way analyses of variance were performed among 1, 3, and 6 months after MACI.</p><p><b>RESULTS</b>The mean T2 values of the transplanted area at 1, 3, and 6 months after MACI were (82.40±15.23), (71.09±13.06), (53.80±4.86) ms, respectively. There were significant differences between the transplanted and control cartilage at 1 and 3 months (both P<0.01) after MACI, but not at 6 months (P=0.196). There were significant differences among T2 values of 1, 3, and 6 months after MACI in transplanted area (P=0.03).</p><p><b>CONCLUSION</b>T2 mapping provides a useful tool for monitoring the biochemical development of the transplanted cartilage and can be used to evaluate the cartilage repair noninvasively.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Cartilage, Articular , Wounds and Injuries , General Surgery , Cell Transplantation , Magnetic Resonance ImagingABSTRACT
<p><b>OBJECTIVE</b>To evaluate the clinical value of magnetic resonance (MR) diffusion-weighted imaging (DWI) for diagnosing radiation-induced liver injury (RILI) and detecting changes in hepatic pathology at different post-irradiation times.</p><p><b>METHODS</b>Male New Zealand white rabbits received no irradiation (C0, control group; n = 10) or irradiation of 50 Gy/10F once every other day by virtual three dimensional conformal radiotherapy (3D-CRT) for one day (C1; n = 10), three days (C2; n = 10), two weeks (C3; n = 10), one month (C4; n = 10) or two months (C5; n = 10). One member of all groups were sacrificed for DWI examination and pathologic study on post-irradiation day 1, day 3, week 2, month 1 and month 2. The apparent diffusion coefficient (ADC) values were measured using a range of b values (50, 300, 600, 800 and 1000 s/mm2).</p><p><b>RESULTS</b>Hematoxylin-eosin (H-E) staining showed that livers of rabbits in the C3, C4 and C5 groups had the characteristic features of veno-occlusive disease. DWI examination showed that the irradiated livers of rabbits in C2, C3, C4 and C5 groups had significantly lower ADC values than the livers of the non-irradiated rabbits at b values of 300, 600, 800 and 1000 s/mm2 (P less than 0.05). When the b value was 600 s/mm2, the best negative correlation between ADC values and pathological stage was seen for the irradiated livers (Spearman's rank, r = -0.459, P less than 0.01). The threshold ADC value to distinguish the normal group (C0) from an irradiated group (more than or equal toC1) was 1.955 * 10-3 mm2/s at 600 s/mm2 b value. When the b value was 1000 s/mm2, the threshold ADC value to predict an irradiated group with normal H-E staining (C1) from an irradiated group with abnormal H-E staining (more than or equal toC2) was 1.5250 * 10-3 mm2/s; the ADC threshold value was 1.5150 * 10-3 mm2/s to predict groups C0-2 and groups C3-5.</p><p><b>CONCLUSION</b>DWI has high sensitivity for detecting RILI at three days after irradiation with proper b values. Use of the ADC value is feasible for estimating the evolutionary process of pathological features of RILI damage. DWI may represent an important clinical tool for detection of early pathological changes in RILI.</p>
ABSTRACT
The applications of three dimensional conformal radiotherapy(3-DCRT)in the abdomen has been associated with the increased incidence of radiation-induced liver injury(RILI). Timely and appropriate evaluation of RILI is particularly important for the design and modification of clinical management of tumors. This article reviews the pathological and serological features of RILI, focusing on in the application of medical imaging.
Subject(s)
Humans , Diagnostic Imaging , Liver , Radiation Effects , Liver Diseases , Radiation Injuries , Diagnosis , Radiotherapy, ConformalABSTRACT
<p><b>OBJECTIVE</b>To explore the methodology as well as the features, quantificational index, and reference standard of 3.0 Tesla magnetic resonance (MR) diffusion-weighted imaging (DWI) on the normal rabbit's liver.</p><p><b>METHODS</b>Twenty New Zealand white rabbits were enrolled and DWI was performed after anesthetics with multi-b values at 3.0 T MR scanner. Apparent diffusion coefficient (ADC) values as well as the difference between maximum and minimum ADC values, signal strength (SH), noise signal (SD), signal to noise ratio (SNR), and quality index (QI) were recorded and analyzed.</p><p><b>RESULTS</b>With b value increased, the ADC values decreased accordingly (P < 0.001). The difference between maximum and minimum ADC values with b = 1000 s/mm2 was the least (good stability), b = 600 s/mm2 was the second least, and b = 300 s/mm2 was greatest (bad stability). The SH decreased at the same time (P < 0.001), but the difference among DWI with b =600, 800, and 1000 s/mm2 was not statistically significant (P > 0.05). The SD decreased at the same time (P < 0.001), but the difference between DWI with b = 800 s/mm2 and b = 1000 s/mm2 was not statistically significant (P > 0.05). The SNR decreased at the same time (P < 0.001), but there were no significant differences between DWI with b = 600 s/mm2 and b = 800 s/mm2 or b = 600 s/mm2 and b = 1000 s/mm2 (P > 0.05). The SNR of DWI with b = 800 s/mm2 and b = 1000 s/mm2 was lower. The QI decreased at the same time (P < 0. 001) , but the difference between DWI with b = 800 s/mm2 and b = 1000 s/mm was not statistically significant (P > 0.05).</p><p><b>CONCLUSION</b>When 3.0 T MR DWI is applied for rabbit liver, it is better to use b = 600 s/mm2 for reducing scanning time and assuring better diffusion weights, quantity of images, and stability of ADC measurement.</p>