T1ρ and T2 mapping reveal the in vivo extracellular matrix of articular cartilage

Purpose:

To determine the relationship between changes in the extracellular matrix (ECM) and T_1ρ and T₂ values in vivo. The ECM is composed of proteoglycan (PG), collagen, and water. It has been unclear which of the ECM constituents affects T_1ρ and T₂ mapping in living human cartilage.

Materials and Methods:

Sagittal T_1ρ and T₂ maps were preoperatively obtained from 20 knee osteoarthritis patients. Osteochondral samples harvested from the resected tibial plateaus during total knee arthroplasty were consistent with the MRIs of the patients' knees. Parameters that included histological grading of cartilage degeneration, glycosaminoglycan (GAG) content (which constitutes PG), presence of collagen anisotropy and water content were evaluated along with T_1ρ and T₂ values, and statistical analysis was performed using multiple regression analysis.

Results:

T_1ρ and T₂ values were significantly correlated with the degree of cartilage degeneration (β = 0.397 and 0.357, respectively) and the GAG content (β = ?0.340 and ?0.244, respectively).

Conclusion:

The present study demonstrated that T_1ρ and T₂ values reflect the GAG content of the cartilage and can indicate cartilage degeneration in vivo. Use of these parameters can facilitate the noninvasive diagnosis and evaluation of cartilage degeneration. J. Magn. Reson. Imaging 2012;35:147‐155. © 2011 Wiley Periodicals, Inc.

     

T1ρ and T2 mapping of the proximal tibiofibular joint in relation to aging and cartilage degeneration

Objective

To study the effects of aging and cartilage degeneration of the proximal tibiofibular- and femorotibial joint (PTFJ, FTJ) on the cartilage of the PTFJ using T₁ρ and T₂ mapping.

Materials and methods

We performed sagittal T₁ρ and T₂ mapping of the PTFJ and FTJ on 55 subjects with knee disorders. We placed 3 regions of interest (ROIs) on images of the cartilage in the PTFJ, medial femoral condyle (MFC), and medial tibia plateau (MTP). Correlation analysis was performed for the T₁ρ and T₂ values of each ROI and the patient age and the osteoarthritic grade of the PTFJ and FTJ.

Results

The T₁ρ and T₂ values of the PTFJ were affected neither by aging nor the osteoarthritic grade of the FTJ. Values of the FTJ normalized to PTFJ values were correlated with the osteoarthritic grade of the FTJ in the MFC (r = 0.851 and 0.779, respectively) and the MTP (r = 0.635 and 0.762, respectively). There was a significant difference in the T₁ρ but not the T₂ value of the PTFJ and MFC between normal and mildly osteoarthritic cartilage of each joint.

Conclusion

We document that the T₁ρ and T₂ values of PTFJ cartilage were not affected by aging or cartilage degeneration in the FTJ. The T₁ρ value of the PTFJ may represent a useful internal standard reference for evaluating early degeneration of the FTJ.     

Changes in the T2 value of cartilage after meniscus transplantation over 1 year

Objectives

To evaluate the changes in the mean T2 values of articular cartilage on serial follow-up images up to 1 year in patients who underwent lateral meniscus allograft transplantation (MAT).

Methods

Fifty-two patients who underwent lateral MAT surgery at our hospital were evaluated preoperatively and at 2 days, 6 weeks, 3 months, 6 months, and 1 year after MAT using 3.0-T magnetic resonance imaging (MRI) that included T2 mapping. T2 value changes according to the arthroscopic grading of chondromalacia were evaluated in the lateral and medial compartment. Lysholm scores were obtained pre- and postoperatively.

Results

The T2 values of cartilage were significantly increased 2 days after operation, and then gradually reduced to the baseline level after 1 year in both compartments. In morphologic assessment performed after 1 year, most areas (92.9 %) showed no interval change of chondromalacia grade. Lyshom knee scores increased significantly from the mean preoperative value of 62.5 (range, 23–95) to 89.7 (range, 64–100) at 1 year (p?<?0.001).

Conclusion

Mean T2 values of cartilage following MAT exhibited a return to baseline level after 1 year. T2 measurement can be a useful tool for quantitative evaluation of postoperative cartilage changes compared to conventional MRI.

Key Points

? T2 mapping provides objective data for longitudinal monitoring following surgery.? Increased cartilage T2 values post-MAT returned to baseline in one year.? Further studies are required to predict the chondroprotective effect of MAT.

     

Osteoarthritis of the knee at 3.0 T: comparison of a quantitative and a semi-quantitative score for the assessment of the extent of cartilage lesion and bone marrow edema pattern in a 24-month longitudinal study

Objective  

To compare a semi-quantitative and a quantitative morphological score for assessment of early osteoarthritis (OA) evolution.     

T2* mapping and delayed gadolinium-enhanced magnetic resonance imaging in cartilage (dGEMRIC) of glenohumeral cartilage in asymptomatic volunteers at 3 T

Objectives

To establish baseline T2* and T1_Gd values of glenohumeral cartilage at 3 T.

Methods

Forty asymptomatic volunteers (mean age: 24.8?±?2.2 years) without shoulder abnormalities were included. The MRI protocol comprised a double-echo steady-state (DESS) sequence for morphological cartilage evaluation, a gradient-echo multiecho sequence for T2* assessment, and a gradient-echo dual-flip-angle sequence for T1_Gd mapping. Statistical assessment involved a one-way analysis of variance (ANOVA) to identify the differences between various regions of the glenohumeral joint and intraclass correlation (ICC) analysis comparing repetitive T2* and T1_Gd measures to assess intra- and interobserver reliability.

Results

Both techniques revealed significant differences between superior and inferior glenohumeral cartilage demonstrating higher T2* (26.2 ms vs. 23.2 ms, P value?<?0.001) and T1_Gd (750.1 ms vs. 720.2 ms, P value?=?0.014) values in the superior regions. No trend was observed in the anterior-posterior measurement (P value range: 0.279–1.000). High intra- and interobserver agreement (ICC value range: 0.895–0.983) was noted for both T2* and T1_Gd mapping.

Conclusions

T2* and T1_Gd mapping are reliable in the assessment of glenohumeral cartilage. The values from this study can be used for comparison to identify cartilage degeneration in patients suffering from shoulder joint abnormalities.

Key Points

? T2* mapping and dGEMRIC are sensitive to collagen degeneration and proteoglycan depletion. ? This study aimed to establish baseline T2*/dGEMRIC values of glenohumeral cartilage. ? Both techniques revealed significant differences between superior and inferior glenohumeral cartilage. ? High intra-/interreader agreement was noted for both T2* mapping and dGEMRIC. ? These baseline normal values should be useful when identifying potential degeneration.     

What is the message of a meeting? Analysis and comparison of the 2458 abstracts of the EANM/WCNMB congress in Berlin and the SNM meeting in Toronto in 1998

The abstracts of the joint congress of EANM/ WCNMB in Berlin 1998 and of the 45th Annual Meeting of the Society of Nuclear Medicine in Toronto 1998 have been analysed and compared in terms of comprehensibility, composition, questions at issue, methods, patient/subject number, type of conclusion and duplication of information between the meetings. All 1362 and 1096 abstracts, respectively, were analysed from the abstract books with regard to ten ”hard” and four ”soft” variables. The dominant topics were new radiopharmaceuticals, methods of synthesis, examination methods, evaluation of examinations, investigation algorithms, technical devicesand novel use of radiopharmaceuticals. In addition to these topics, there were numerous reports about established radiopharmaceuticals and techniques, often without a specific merit mentioned. There were also many abstracts with questions outside nuclear medicine, but using such techniques. Few papers reported negative findings or dealt with quality assurance, dosimetry, and cost-effectiveness. Many of the conclusions contained hyperbole. Some abstracts were very extensive and detailed. Sixty-seven contributions conveyed identical information at both meetings. Structured and/or paragraphed abstracts promote clarity and reduce the number of lines that need to be read in order to comprehend the background and aim of the abstract. Such contributions were more frequent at the EANM/WCNMB congress while the SNM meeting covered a wider field with a greater representation of radiophysics, instrumentation, and computer evaluations.     

Uptake of 99mTc-labeled chondroitin sulfate by chondrocytes and cartilage: a promising agent for imaging of cartilage degeneration?

Chondroitin sulfate (CS) is used in the treatment of human osteoarthritis as a slow-acting symptomatic drug. For this reason, we performed uptake studies with ^99mTcCS using different chondrocyte cultures, as well as cartilage tissue in vitro.For uptake studies, adherent monolayer cultures of human chondrocytes (2.7×10⁴ cells/well) and ^99mTcCS (1 μCi) were used. In parallel, we also performed uptake studies with cell suspensions of human chondrocytes at 1×10⁶ cells/well incubated with ^99mTcCS (5 μCi) under identical conditions. Uptake was studied also in cartilage tissue samples and frozen tissue sections for autoradiography. The uptake was monitored for 10–240 min, every 10–30 min for cell cultures and for cartilage tissue up to 72 h. As the commercially available drug Condrosulf (IBSA, Lugano, Switzerland) contains magnesium (Mg) stearate as additive, we investigated the uptake with and without this additive. The washout of the tracer was assessed after the uptake experiments with PBS buffer for different time intervals (10 min–3 h).Tracer uptake in monolayer±additives with low number of cells was low. With the use of chondrocytes in culture suspensions with higher number of cells, a higher uptake of 5.9±0.65% and 1.0±0.1% (n=6) was found, with and without additive, respectively. The saturation was achieved after 100 min. With the use of human rib cartilage, the uptake of ^99mTcCS was continuously increasing with time and was very high with additive amounting to 101.8±5.2% vs. 53.0±8.3% (n=6) without after 72 h and showing delayed saturation up to 30 h. Thus, not only the resorption of the drug is enhanced by Mg-stearate, but also the uptake. The washout of the tracer from cartilage after 3 h of uptake amounted to 3.75±1.5% with additive vs. 13.1±2.1% without. After 24 h, washout was lower amounting to 1.75±0.15% vs. 3.25±0.25%, respectively. The autoradiographic studies paralleled the results of in vitro cartilage tissue uptake.These data show that ^99mTcCS accumulates in cartilage tissue, either by acting as a substrate for proteoglycan synthesis or by adsorption to cartilage. ^99mTcCS could therefore be a possible agent to target and radioimage osteoarthritis.     

Does joint alignment affect the T2 values of cartilage in patients with knee osteoarthritis?

Objective  

To assess the relationship between T2 values of femorotibial cartilage and knee alignment in patients with clinical symptoms of medial osteoarthritis (OA).     

Ossification and pseudoepiphysis formation in the “nonepiphyseal” end of bones of the hands and feet

Metacarpals, metatarsals, and phalanges were studied to assess the developmental morphology of secondary ossification in the nonepiphyseal ends of these bones as well as the formation of the pseudoepiphysis as an epiphyseal ossification variant. Both direct ossification extension from the metaphysis into the epiphysis and pseudoepiphysis formation preceded, and continued to be more mature than, formation and expansion of the classic epiphyseal (secondary) ossification center at the opposite end of each specific bone. Direct metaphyseal to epiphyseal ossification usually started centrally and expanded hemispherically, replacing both physeal and epiphyseal cartilage simultaneously. In contrast, when remnants of physis were retained, while juxtaposed epiphyseal cartilage was replaced, a pseudoepiphysis formed. There were three basic patterns of pseudoepiphysis formation. First, a central osseous bridge extended from the metaphysis across the physis into the epiphysis and subsequently expanded to create a mushroom-like osseous structure. In the second pattern a peripheral osseous bridge formed, creating either an osseous ring or an eccentric bridge between the metaphysis and the epiphysis. In the third pattern, multiple bridging occurred. In each situation the associated remnant physis lacked typical cell columns and was incapable of significantly contributing to the postnatal longitudinal growth of the involved bone. Pseudoepiphyses were well formed by 4–5 years and coalesced with the rest of the bone months of years before skeletal maturation was attained at the opposite epiphyseal end, which ossified in the typical pattern (i.e., formation of a secondary center de novo completely within the cartilaginous epiphysis). This process may also affect the development and appearance of ossification within the longitudinal epiphyseal bracket (delta phalanx).     

Cell-free repair of small cartilage defects in the Goettinger minipig: which defect size is possible?

Purpose

Cartilage repair of full-thickness chondral defects in the knees of Goettinger minipigs was assessed by treatment with cell-free collagen type-I gel plugs of three different sizes.

Methods

In 6 adult Goettinger minipigs, three full-thickness chondral defects were created in the trochlear groove of one knee of the hind leg. These defects were treated with a cell-free collagen type-I gel plug of 8, 10, or 12 mm diameter. All animals were allowed unlimited weight bearing. After 1 year, the animals were killed. Immediately after recovery, a non-destructive biomechanical testing was performed. The repair tissue quality was evaluated immunohistologically, collagen type-II protein was quantified, and a semiquantitative score (O’Driscoll score) was calculated.

Results

After 1 year, a high number of cells migrated into the initially cell-free collagen gel plugs and a hyaline-like repair tissue had been created. The O’Driscoll scores were: 8 mm, 21.2 (SD, 2.8); 10 mm, 21.5 (SD, 1.6); and 12 mm, 22.3 (SD, 1.0). The determination of the e-modulus, creep and relaxation revealed that mechanical properties of the two smaller defects were closer to unaffected hyaline cartilage.

Conclusions

As cell-free collagen type-I gel plugs of all three different sizes created hyaline-like repair tissue, this system seems suitable for the treatment of even larger defects.     

What is the message of a meeting? Analysis and comparison of the 2458 abstracts of the EANM/WCNMB congress in Berlin and the SNM meeting in Toronto in 1998. European Association of Nuclear Medicine/World Federation of Nuclear Medicine and Biology, and the Society of Nuclear Medicine

The abstracts of the joint congress of EANM/WCNMB in Berlin 1998 and of the 45th Annual Meeting of the Society of Nuclear Medicine in Toronto 1998 have been analysed and compared in terms of comprehensibility, composition, questions at issue, methods, patient/subject number, type of conclusion and duplication of information between the meetings. All 1362 and 1096 abstracts, respectively, were analysed from the abstract books with regard to ten "hard" and four "soft" variables. The dominant topics were new radiopharmaceuticals, methods of synthesis, examination methods, evaluation of examinations, investigation algorithms, technical devices and novel use of radiopharmaceuticals. In addition to these topics, there were numerous reports about established radiopharmaceuticals and techniques, often without a specific merit mentioned. There were also many abstracts with questions outside nuclear medicine, but using such techniques. Few papers reported negative findings or dealt with quality assurance, dosimetry, and cost-effectiveness. Many of the conclusions contained hyperbole. Some abstracts were very extensive and detailed. Sixty-seven contributions conveyed identical information at both meetings. Structured and/or paragraphed abstracts promote clarity and reduce the number of lines that need to be read in order to comprehend the background and aim of the abstract. Such contributions were more frequent at the EANM/WCNMB congress while the SNM meeting covered a wider field with a greater representation of radiophysics, instrumentation, and computer evaluations.     

Morphological imaging and T2 and T2* mapping of hip cartilage at 7 Tesla MRI under the influence of intravenous gadolinium

Objectives

To investigate the influence of intravenous gadolinium on cartilage T2 and T2* relaxation times and on morphological image quality at 7-T hip MRI.

Methods

Hips of 11 healthy volunteers were examined at 7 T. Multi-echo sequences for T2 and T2* mapping, 3D T1 volumetric interpolated breath-hold examination (VIBE) and double-echo steady-state (DESS) sequences were acquired before and after intravenous application of gadolinium according to a delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) protocol. Cartilage relaxation times were measured in both scans. Morphological sequences were assessed quantitatively using contrast ratios and qualitatively using a 4-point Likert scale. Student’s t-test, Pearson’s correlation (ρ) and Wilcoxon sign-rank test were used for statistical comparisons.

Results

Pre- and post-contrast T2 and T2* values were highly correlated (T2: acetabular: ρ?=?0.76, femoral: ρ?=?0.77; T2*: acetabular: ρ?=?0.80, femoral: ρ?=?0.72). Gadolinium enhanced contrasts between cartilage and joint fluid in DESS and T1 VIBE according to the qualitative (p?=?0.01) and quantitative (p?<?0.001) analysis. The delineation of acetabular and femoral cartilage and the labrum predominantly improved with gadolinium.

Conclusions

Gadolinium showed no relevant influence on T2 or T2* relaxation times and improved morphological image quality at 7 T. Therefore, morphological and quantitative sequences including dGEMRIC can be conducted in a one-stop-shop examination.

Key Points

? Hip cartilage T2 values correlate highly before and after gadolinium at 7 T ? Hip cartilage T2* values correlate highly before and after enhancement at 7 T ? Morphological hip cartilage imaging benefits from intravenous gadolinium at 7 T ? The delineation of acetabular and femoral cartilage can be improved by gadolinium ? Morphological and quantitative sequences including dGEMRIC can be combined as a one-stop-shop examination

     

The ethical and legal responsibilities of the medical profession in relation to Torture and the implications of any form of participation by doctors in Torture∗

The terrorist attack on the USS Cole on 12 October 2000 was remarkably similar to the 1987 attack on the USS Stark. This article discusses the psychosocial consequences of the attacks on the families and crews of the ships and the community response of the Navy to the attacks, particularly that of the Navy Family Service Centers. The impact of the attacks is compared to the impact of natural and man‐made disasters on communities while the impact on the crew is examined in light of combat psychiatry and post‐traumatic stress disorder (PTSD). Events such as these are very likely to produce PTSD despite early intervention efforts. Following the attack on the Stark greater attention was given to the grief of family members than to the trauma of the crew, while the crew of the Cole has received longer‐term psychiatric assistance than in previous similar episodes.     

Location of the “zero zone” and its role in the pathogenesis of cervical spondylosis

Summary Significant correlation between the location of the zero zone and spondylosis was found in the cervical spine. The possible role of the zero zone in the development of spondylosis is suggested and the deleterious effect of counteracting forces as compared with a unidirectional traction is stressed.

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Die Stelle der Nullzone und ihre Rolle in der Pathogenese der zervikalen Spondylose

Zusammenfassung Die Ergebnisse der dynamischen Studien scheinen darauf hinzuweisen, daß ein Zusammenhang zwischen den häufigsten Stellen der Nullzone und der Spondylose besteht. Es scheint, daß das Bindegewebssystem der Halswirbelsäule auf die Überlastung durch entgegengesetzte Zugkomponenten sehr empfindlich ist und durch diese stärker beschädigt wird als durch eine Traktion, die nur in einer Richtung ausgeübt wird.

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Localisation de la zone zero et son rôle dans la pathogenie de la spondylose cervicale

Résumé Il semble y avoir une corrélation entre la zone zéro et le développement d'une spondylose cervicale et que la détérioration discale se fasse spécialement au niveau des mouvements intervertébraux bidirectionnels opposés.

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From the annual congress of the European Society of Neuroradiology (Geilo, September 1975)     

Quantitative evaluation of knee cartilage and meniscus destruction in patients with rheumatoid arthritis using T1ρ and T2 mapping

ObjectiveTo calculate T1ρ and T2 values of articular cartilage and menisci in knee joints of patients with RA, and compare the values between RA patients and healthy volunteers, to gain insight into the pathogenesis of cartilage and meniscus degradation in patients with RA.Materials and methodsNine patients with RA and knee joints symptoms were enrolled in the study, twenty healthy volunteers without knee joint diseases were included as controls. Sagittal fat-saturated T1ρ and T2 mapping images were obtained on a 3T MR scanner (GE750, GE Healthcare, Waukesha, WI), using a dedicated 8-channel knee coil. In the T1rho mapping sequence, the amplitude of the spin-lock pulse was 500 Hz, spin lock durations = 10/20/30/50 ms. In the T2 mapping sequence,TR/TE were 1794/6.5, 13.4, 27, 40.7 ms. Both sequences were performed with the following parameters: flip angle (FA) = 90°, matrix: 320 × 256, FOV: 16 × 16 cm², slice thickness: 3 mm, bandwidth: 62.5 kHZ, and a total scan time of 5:11 min. T1ρ- and T2-mapping images were used for the segmentation of the articular cartilage of the patella, femoral trochlea, medial and lateral femoral condyle, medial and lateral tibial plateau. These images were also used for the segmentation of the anterior and posterior horns of the medial and lateral menisci with livewire semi-automatic segmentation algorithm of MATLAB. A Mann–Whitney U test was performed to compare the T1ρ and T2 values of the above mentioned regions between the two groups.ResultsT1ρ (Z = −3.913 to −2.121, P = 0.000–0.034) and T2 (Z = −3.866 to −2.216, P = 0.000–0.026) values of knee cartilage in patients with RA were higher than that in healthy volunteers, except the cartilage of the patella (T1ρ: Z = −1.273, P = 0.203,T2: Z = −0.236, P = 0.814) and lateral tibial plateau (T1ρ:Z = −1.037, P = 0.317). The T1ρ (Z = −1.462 to 0.572, P = 0.095–0.908) and T2 (Z = −1.461 to 0.278, P = 0.153–0.764) values of medial and lateral menisci showed no difference between the two groups.ConclusionPatients with RA exhibit diffuse knee cartilage destruction in the medial and lateral tibiofemoral joints and in the femoral trochlea. However, we found no increase in T1ρ and T2 values in menisci, this finding warrants further investigation.     

Do anatomic variants of the acromion shape in the frontal plane influence pain and function in calcifying tendinitis of the shoulder?

Purpose  

To evaluate the relationship of a large acromion index and calcifying tendinitis of the supraspinatus tendon at the shoulder.     

Effects of Acute γ-irradiation on the Development of the Thymus in Embryos and Fry of Oryzias Latipes

An automated variant the of micronucleus assay for erythrocytes in mouse peripheral blood has recently been developed. The flow-cytometric technique used allows very large numbers of erythrocytes to be analysed with a relatively small effort. Here we report the potential of this method to detect a response to extended low-dose-rate exposure to γ-irradiation. The mice were irradiated with a ¹³⁷Cs source at a dose rate of 4·8 cGy/day for 26 days. Sampling was continued for another 39 days after irradiation. Elevated frequencies compared with the control group were found at days 2, 9 and 20 after the start of the irradiation for micronucleated polychromatic erythrocytes, and at days 9, 20, 29, 42, 51 and 65 for micronucleated normochromatic erythrocytes.     

Femoral bone and cartilage wear is predictable at 0° and 90° in the osteoarthritic knee treated with total knee arthroplasty

Purpose

Kinematically aligned total knee arthroplasty (TKA) positions the femoral component at the natural angle and level of the distal (0°) and posterior (90°) joint line. This technique applies referencing guides at 0° and 90° that are adjusted to compensate for wear and kerf and perform resections equal in thickness to the femoral component. Knowing whether femoral bone and cartilage wear is predictable would assist in establishing general guidelines for adjusting the resection level of these two referencing guides. This study tests the hypothesis that femoral bone and cartilage wear is predictable at 0° and 90° in the varus and valgus osteoarthritic knee treated with TKA.

Methods

The study consists of 205 patients and 208 knees with Kellgren–Lawrence Grade 3 or 4 osteoarthritis and treated with a TKA. Each knee had a narrow slice (2 mm) preoperative 1.5 tesla magnetic resonance image in the sagittal plane. Femoral bone and cartilage wear at 0° and 90° was computed from best-fit circles superimposed on the peripheral boundary of the subchondral bone on the medial and lateral femoral condyles.

Results

Overall, 99.5 % of knees had minimal bone wear (<1 mm) at 0° and 90°. In the 74 % (154 of 208) of knees with a varus deformity, 92 % at 0° and 2 % at 90° had >1 mm cartilage wear on the medial femoral condyle. In the 26 % (54 of 208) of knees with a valgus deformity, 78 % at 0° and 55 % at 90° had ≥1 mm cartilage wear on the lateral femoral condyle.

Conclusions

As a general guideline, adjustment for femoral bone wear is rarely required when performing kinematically aligned TKA. Most osteoarthritic knees require adjustment of the distal referencing guide to compensate for cartilage wear on the medial femoral condyle in the varus knee and the lateral femoral condyle in the valgus knee. Adjustment of the posterior referencing guide is required in about half of valgus osteoarthritic knees to compensate for lateral cartilage wear at 90°. Knowing that bone wear is rare and cartilage wear is predictable in varus and valgus Kellgren–Lawrence Grade 3 or 4 osteoarthritic knees helps establish general guidelines for adjusting the distal and posterior femoral referencing guides to restore the natural angle and level of the femoral joint lines when performing kinematically aligned TKA with generic instruments.

Level of evidence

IV.