Comparison between 1.5T and 3.0T MRI: both field strengths sensitively detect subclinical inflammation of hand and forefoot in patients with arthralgia

Objective: Magnetic resonance imaging (MRI) of small joints sensitively detects inflammation. This inflammation, and tenosynovitis in particular, has been shown to predict rheumatoid arthritis (RA) development in arthralgia patients. These data have predominantly been acquired on 1.0-1.5 T MRI. However, 3.0 T is now commonly used in practice. Evidence on the comparability of these field strengths is scarce and has never included subtle inflammation in arthralgia patients or tenosynovitis. Therefore, we assessed the comparability of 1.5 T and 3.0 T in detecting subclinical inflammation in arthralgia patients.Method: A total of 2968 locations (joints, bones, tendon sheaths) in the hands and forefeet of 28 patients with small-joint arthralgia, at risk for RA, were imaged on both 1.5 and 3.0 T MRI. Two blinded readers independently scored erosions, osteitis, synovitis, and tenosynovitis, in line with the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS). Features were summed into inflammation (osteitis, synovitis, tenosynovitis) and RAMRIS (inflammation and erosions). Agreement was assessed with intraclass correlation coefficients (ICCs) for continuous scores and after dichotomization into presence or absence of inflammation, on patient and location levels.Results: Interreader ICCs were excellent (> 0.90). Comparing 1.5 and 3.0 T revealed an ICC of 0.90 for inflammation and RAMRIS. ICCs for individual inflammation features were: tenosynovitis 0.87 (95% confidence interval 0.74-0.94), synovitis 0.65 (0.24-0.84), and osteitis 0.96 (0.91-0.98). Agreement was 83% for inflammation and 89% for RAMRIS. Analyses on the location level showed similar results.Conclusion: Agreement on subclinical inflammation between 1.5 T and 3.0 T was excellent. Although synovitis scores were slightly different, synovitis often occurs simultaneously with other inflammatory signs, suggesting that scientific results on the predictive value of MRI-detected inflammation for RA, obtained on 1.5 T MRI, can be generalized to 3.0 T MRI.

Personalising sarcoma care using quantitative multimodality imaging for response assessment

Over the last decades, technological developments in the field of radiology have resulted in a widespread use of imaging for personalising medicine in oncology, including patients with a sarcoma. New scanner hardware, imaging protocols, image reconstruction algorithms, radiotracers, and contrast media, enabled the assessment of the physical and biological properties of tumours associated with response to treatment. In this context, medical imaging has the potential to select sarcoma patients who do not benefit from (neo-)adjuvant treatment and facilitate treatment adaptation. Due to the biological heterogeneity in sarcomas, the challenge at hand is to acquire a practicable set of imaging features for specific sarcoma subtypes, allowing response assessment. This review provides a comprehensive overview of available clinical data on imaging-based response monitoring in sarcoma patients and future research directions. Eventually, it is expected that imaging-based response monitoring will help to achieve successful modification of (neo)adjuvant treatments and improve clinical care for these patients.

Effusion attenuates the effect of synovitis on radiographic progression in patients with hand osteoarthritis: a longitudinal magnetic resonance imaging study

An exploratory study to determine the role of effusion, i.e., fluid in the joint, in pain, and radiographic progression in patients with hand osteoarthritis. Distal and proximal interphalangeal joints (87 patients, 82% women, mean age 59 years) were assessed for pain. T2-weighted and Gd-chelate contrast-enhanced T1-weighted magnetic resonance images were scored for enhanced synovial thickening (EST, i.e., synovitis), effusion (EST and T2-high signal intensity [hsi]) and bone marrow lesions (BMLs). Effusion was defined as follows: (1) T2-hsi > 0 and EST = 0; or 2) T2-hsi = EST but in different joint locations. Baseline and 2-year follow-up radiographs were scored following Kellgren-Lawrence, increase ≥ 1 defined progression. Associations between the presence of effusion and pain and radiographic progression, taking into account EST and BML presence, were explored on the joint level. Effusion was present in 17% (120/691) of joints, with (63/120) and without (57/120) EST. Effusion on itself was not associated with pain or progression. The association with pain and progression, taking in account other known risk factors, was stronger in the absence of effusion (OR [95% CI] 1.7 [1.0–2.9] and 3.2 [1.7–5.8]) than in its presence (1.6 [0.8–3.0] and 1.3 [0.5–3.1]). Effusion can be assessed on MR images and seems not to be associated with pain or radiographic progression but attenuates the association between synovitis and progression.

Key Points • Effusion is present apart from synovitis in interphalangeal joints in patients with hand OA. • Effusion in finger joints can be assessed as a separate feature on MR images. • Effusion seems to be of importance for its attenuating effect on the association between synovitis and radiographic progression.

Assessment of osteoarthritic features in the thumb base with the newly developed OMERACT magnetic resonance imaging scoring system is a valid addition to standard radiography

OBJECTIVE

To investigate the construct validity of the new thumb base OA magnetic resonance imaging (MRI) scoring system (TOMS) by comparing TOMS scores with radiographic scores in patients with primary hand OA.

DESIGN

In 200 patients (83.5% women, mean (SD) age 61.0 (8.4) years), postero-anterior radiographs and MR scans (1.5 T) of the right first carpometacarpal (CMC-1) and scaphotrapeziotrapezoid (STT) joints, were scored using the OARSI atlas and TOMS, respectively. The distributions of the TOMS scores (specified in results section) were stratified for the OARSI scores of corresponding radiographic features and investigated using boxplots and non-parametric tests. Furthermore, Spearman's rank or Phi correlation coefficients (ρ/φ) were calculated.

RESULTS

For all features, especially for erosions and osteophytes, the prevalence found with MRI was higher than with radiography. TOMS osteophyte and cartilage loss scores differed statistically significant between corresponding OARSI scores in CMC-1 (0 vs 1; 1 vs 2). TOMS scores were positively correlated with radiographic scores in CMC-1 for osteophytes (coefficient [95% confidence interval], ρ = 0.75 [0.69; 0.81]), cartilage loss/joint space narrowing (ρ = 0.70 [0.62; 0.76]), subchondral bone defects (SBDs)/erosion-cyst (ρ = 0.41 [0.29; 0.52]), bone marrow lesions (BMLs)/subchondral sclerosis (ρ = 0.65 [0.56; 0.73]) and subluxation (φ = 0.65 [0.57; 0.73]); and in STT for osteophytes (ρ = 0.30 [0.17; 0.42]) and cartilage loss/joint space narrowing (ρ = 0.53 [0.42; 0.62]).

CONCLUSIONS

In patients with hand OA, TOMS scores positively correlated with radiographic scores, indicating good construct validity. However, the prevalence of features on MR images was higher compared to radiographs, suggesting that TOMS might be more sensitive than radiography. The clinical meaning of these extra MR detected cases is currently still unknown.

18F-FDG PET-CT versus MRI for detection of skeletal metastasis in Ewing sarcoma

OBJECTIVE

To determine the level of discrepancy between magnetic resonance imaging (MRI) and ¹⁸F-FDG PET-CT in detecting osseous metastases in patients with Ewing sarcoma.

METHODS

Twenty patients with histopathologically confirmed Ewing sarcoma between 2000 and 2017 who underwent ¹⁸F-FDG PET-CT and MRI within a 4-week range were included. Each imaging modality was evaluated by a separate observer. Reference diagnosis of each lesion was based on histopathology or consensus of an expert panel using all available data, including at least 6 months' follow-up. Sensitivity, specificity, and predictive values were determined. Osseous lesions were analyzed on a patient and a lesion basis. Factors possibly related to false-negative findings were evaluated using Pearson's Chi-squared or Fisher's exact test.

RESULTS

A total of 112 osseous lesions were diagnosed in 13 patients, 107 malignant and 5 benign. Seven patients showed no metastases on either ¹⁸F-FDG PET-CT or MRI. Forty-one skeletal metastases (39%) detected with MRI did not show increased ¹⁸F-FDG uptake on ¹⁸F-FDG PET-CT (false-negative). Lesion-based sensitivities and specificities were 62% (95%CI 52-71%) and 100% (48-100%) for ¹⁸F-FDG PET-CT; and 99% (97-100%) and 100% (48-100%) for MRI respectively. Bone lesions were more likely to be false-negative on ¹⁸F-FDG PET-CT if hematopoietic bone marrow extension was widespread and active (p = 0.001), during or after (neo)-adjuvant treatment (p = 0.001) or when the lesion was smaller than 10 mm (p < 0.001).

CONCLUSION

Although no definite conclusions can be drawn from this small retrospective study, it shows that caution is needed when using ¹⁸F-FDG PET-CT for diagnosing skeletal metastases in Ewing sarcoma. Poor contrast between metastases and active hematopoietic bone marrow, chemotherapeutic treatment, and/or small size significantly decrease the diagnostic yield of ¹⁸F-FDG PET-CT, but not of MRI.

In thumb base osteoarthritis structural damage is more strongly associated with pain than synovitis

OBJECTIVE

Osteoarthritis in thumb base joints (first carpometacarpal (CMC-1), scaphotrapeziotrapezoid (STT)) is prevalent and disabling, yet focussed studies are scarce. Our aim was to investigate associations between ultrasonographic and magnetic resonance imaging (MRI) inflammatory features, radiographic osteophytes, and thumb base pain in hand osteoarthritis patients.

DESIGN

Cross-sectional analyses were performed in cohorts with MRI (n = 202) and ultrasound measurements (n = 87). Pain upon thumb base palpation was assessed. Radiographs were scored for CMC-1/STT osteophytes. Synovial thickening, effusion and power Doppler signal in CMC-1 joints were assessed with ultrasound. MRIs were scored for synovitis and bone marrow lesions (BMLs) in CMC-1 and STT joints using OMERACT-TOMS. Associations between ultrasound/MRI features, osteophytes, and thumb base pain were assessed. Interaction between MRI features and osteophytes was explored.

RESULTS

In 289 patients (mean age 60.2, 83% women) 139/376 thumb bases were painful. Osteophyte presence was associated with pain (MRI cohort: odds ratio (OR) 5.1 (2.7-9.8)). Ultrasound features were present in 25-33% of CMC-1 joints, though no associations were seen with pain. MRI-synovitis and BMLs grade ≥2 were scored in 25% and 43% of thumb bases, and positively associated with pain (OR 3.6 (95% CI 1.7-7.6) and 3.0 (1.6-5.5)). Associations attenuated after adjustment for osteophyte presence. Combined presence of osteophytes and MRI-synovitis had an additive effect.

CONCLUSIONS

Ultrasonographic and MRI inflammatory features were often present in the thumb base. Osteophytes were more strongly associated with thumb base pain than inflammatory features, in contrast to findings in finger OA studies, supporting thumb base osteoarthritis as a distinct phenotype.

Comparison of histological and morphometrical changes underlying subchondral bone abnormalities in inflammatory and degenerative musculoskeletal disorders: a systematic review

OBJECTIVE

Subchondral bone abnormalities (SBAs) on magnetic resonance imaging (MRI) are observed frequently and associated with disease course in various musculoskeletal disorders. This review aims to map the existing knowledge of their underlying histological features, and to identify needs for future research.

DESIGN

We conducted a systematic review following PRISMA guidelines until September 2017, including all studies correlating histological features to on MRI defined SBAs in patients with osteoarthritis (OA), rheumatoid arthritis (RA), spondyloarthritis (SpA) and degenerative disc disease (DDD). Two authors independently retrieved articles and assessed study quality.

RESULTS

A total of 21 studies (466 patients) correlated histological features to SBAs in OA (n = 13), RA (n = 3), ankylosing spondylitis (AS) (n = 1) and DDD (n = 4). Reported changes in OA were substitution of normal subchondral bone with fibrosis and necrosis, and increased bone remodeling. In contrast, in RA, AS or DDD fibrosis was not reported and SBAs correlated to an increase in inflammatory cell number. In DDD necrosis was observed. Similar to OA, increased bone remodeling was shown in RA and DDD. The risk of bias assessment showed a lack in described patient criteria, blinding and/or adequate topographic correlation in approximately half of studies. There was heterogeneity regarding the investigated histological features between the different disorders.

CONCLUSIONS

Current studies suggest that SBAs correlate to various histological features, including fibrosis, cell death, inflammation and bone remodeling. In the majority of studies most quality criteria were not met. Future studies should aim for high quality research, and consistency in investigated features between different disorders.

Severity classification of Tenosynovial Giant Cell Tumours on MR imaging

AIM

Current development of novel systemic agents requires identification and monitoring of extensive Tenosynovial Giant Cell Tumours (TGCT). This study defines TGCT extension on MR imaging to classify severity.

METHODS

In part one, six MR parameters were defined by field-experts to assess disease extension on MR images: type of TGCT, articular involvement, cartilage-covered bone invasion, and involvement of muscular/tendinous tissue, ligaments or neurovascular structures. Inter- and intra-rater agreement were calculated using 118 TGCT MR scans. In part two, the previously defined MR parameters were evaluated in 174 consecutive, not previously used, MR-scans. TGCT severity classification was established based on highest to lowest Hazard Ratios (HR) on first recurrence.

RESULTS

In part one, all MR parameters showed good inter- and intra-rater agreement (Kappa≥0.66). In part two, cartilage-covered bone invasion and neurovascular involvement were rarely appreciated (<13%) and therefore excluded for additional analyses. Univariate analyses for recurrent disease yielded positive associations for type of TGCT HR12.84(95%CI4.60-35.81), articular involvement HR6.00(95%CI2.14-16.80), muscular/tendinous tissue involvement HR3.50(95%CI1.75-7.01) and ligament-involvement HR4.59(95%CI2.23-9.46). With these, a TGCT severity classification was constructed with four distinct severity-stages. Recurrence free survival at 4 years (log rank p < 0.0001) was 94% in mild localized (n56, 1 recurrence), 88% in severe localized (n31, 3 recurrences), 59% in moderate diffuse (n32, 12 recurrences) and 36% in severe diffuse (n55, 33 recurrences).

CONCLUSION

The proposed TGCT severity classification informs physicians and patients on disease extent and risk for recurrence after surgical treatment. Definition of the most severe subgroup attributes to a universal identification of eligible patients for systemic therapy or trials for novel agents.

Prevalence and clinical significance of lumbosacral transitional vertebra (LSTV) in a young back pain population with suspected axial spondyloarthritis: results of the SPondyloArthritis Caught Early (SPACE) cohort

OBJECTIVE

To determine in a cohort of young patients with suspected axial spondyloarthritis (axSpA), the prevalence of lumbosacral transitional vertebra (LSTV), its association with local bone marrow edema (BME) and lumbar spine degeneration, and the potential relationship with MRI findings and clinical signs of axSpA.

MATERIALS AND METHODS

Baseline imaging studies and clinical information of patients from the SPondyloArthritis Caught Early-cohort (back pain ≥3 months, ≤2 years, onset <45 years) were used. Two independent readers assessed all patients for LSTV on radiography, and BME-like and degenerative changes on MRI. Patients with and without LSTV were compared with regard to the prevalence of MRI findings and the results of clinical assessment using Chi-squared test or t test.

RESULTS

Of 273 patients (35.1% male, mean age 30.0), 68 (25%) patients showed an LSTV, without statistical significant difference between patients with and without axSpA (p = 0.327). Local sacral BME was present in 9 out of 68 (13%) patients with LSTV and absent in patients without LSTV (p < 0.001). Visual analogue scale (VAS) pain score and spinal mobility assessments were comparable.

CONCLUSIONS

LSTV is of low clinical relevance in the early diagnosis of axSpA. There is no difference between patients with and without LSTV regarding the prevalence of axSpA, pain and spinal mobility, and a BME-like pattern at the pseudoarticulation does not reach the SI joints.

Bone marrow lesions and synovitis on MRI associate with radiographic progression after 2 years in hand osteoarthritis

OBJECTIVE

To study the association of magnetic resonance (MR) features with radiographic progression of hand osteoarthritis over 2 years.

METHODS

Of 87 primary patients with hand osteoarthritis (82% women, mean age 59 years), baseline distal and proximal interphalangeal joint contrast-enhanced MR images were scored 0-3 for bone marrow lesions (BMLs) and synovitis following the Oslo score. Baseline and 2-year follow-up radiographs were scored following Kellgren-Lawrence (KL) (0-4) and OsteoArthritis Research Society International (OARSI) scoring methods (0-3 osteophytes, joint space narrowing (JSN)). Increase ≥1 defined progression. Associations between MR features and radiographic progression were explored on joint and on patient level, adjusting for age, sex, body mass index, synovitis and BML. Joints in end-stage were excluded.

RESULTS

Of 696 analysed joints, 324 had baseline KL=0, 28 KL=4 and after 2 years 78 joints progressed. BML grade 2/3 was associated with KL progression (2/3 vs 0: adjusted risk ratio (RR) (95% CI) 3.3 (2.1 to 5.3)) and with osteophyte or JSN progression, as was synovitis. Summated scores were associated with radiographic progression on patient level (RR crude BML 1.08 (1.01 to 1.2), synovitis 1.09 (1.04 to 1.1), adjusted synovitis 1.08 (1.03 to 1.1)).

CONCLUSIONS

BMLs, next to synovitis, show, already after 2 years, graded associations with radiographic progression, suggesting that both joint tissues could be important targets for therapy.

Bakers' cyst and tibiofemoral abnormalities are more distinctive MRI features of symptomatic osteoarthritis than patellofemoral abnormalities

OBJECTIVE

To investigate which structural MR abnormalities discriminate symptomatic knee osteoarthritis (OA), taking co-occurrence of abnormalities in all compartments into account.

METHODS

The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45-65 years. In 1285 participants (median age 56 years, 55% women, median body mass index (BMI) 30 kg/m(2)), MRI of the right knee were obtained. Structural abnormalities (osteophytes, cartilage loss, bone marrow lesions (BMLs), subchondral cysts, meniscal abnormalities, effusion, Baker's cyst) at 9 patellofemoral and tibiofemoral locations were scored following the knee OA scoring system. Symptomatic OA in the imaged knee was defined following the American College of Rheumatology criteria. Logistic ridge regression analyses were used to investigate which structural abnormalities discriminate best between individuals with and without symptomatic OA, crude and adjusted for age, sex and BMI.

RESULTS

Symptomatic knee OA was present in 177 individuals. Structural MR abnormalities were highly frequent both in individuals with OA and in those without. Baker's cysts showed the highest adjusted regression coefficient (0.293) for presence of symptomatic OA, followed by osteophytes and BMLs in the medial tibiofemoral compartment (0.185-0.279), osteophytes in the medial trochlear facet (0.262) and effusion (0.197).

CONCLUSIONS

Baker's cysts discriminate best between individuals with and without symptomatic knee OA. Structural MR abnormalities, especially in the medial side of the tibiofemoral joint and effusion, add further in discriminating symptomatic OA. Baker's cysts may present as a target for treatment.

Characterization of synovial mast cells in knee osteoarthritis: association with clinical parameters

OBJECTIVE

To investigate the presence of mast cells in the osteoarthritic (OA) synovium and their association with clinical parameters in comparison with rheumatoid arthritis (RA) samples.

METHOD

Synovial tissues of 56 symptomatic OA and 49 RA patients were obtained. Two to three paraffin slides were used to quantify inflammation using haematoxylin and eosin (H&E) staining (synovitis score 0-9), and numbers of mast cells (per 10 high-power fields) using double immunofluorescence for CD117 and tryptase. Average scores per patient were used for analysis. Knee radiographs of OA patients were scored according to the Kellgren and Lawrence (KL) system and pain was determined in OA patients at baseline by visual analogue scale (VAS).

RESULTS

Median (range) of mast cells was significantly higher in OA samples 45 (1-168) compared to RA samples 4 (1-47) (P-value < 0.001), despite a lower median (range) synovitis score in OA (2.5 (0-6.0)) compared to 4.6 (0-8.0) in RA samples. The synovitis score was significantly correlated with the number of mast cells (in OA Spearman's rho (P-value) 0.3 (0.023) and RA 0.5 (P-value < 0.001)). Interestingly, we observed a trend towards an association between the number of mast cells and an increased KL-grade (P-value 0.05) in OA patients, independently of synovitis. No associations were found with self-reported pain.

CONCLUSION

Prevalence of mast cells in OA synovial tissue is relatively high and associates with structural damage in OA patients, suggesting a role of mast cells in this disease.

Radiographic progression of knee osteoarthritis is associated with MRI abnormalities in both the patellofemoral and tibiofemoral joint

OBJECTIVE

To investigate patterns of MRI abnormalities in the patellofemoral (PFJ) and tibiofemoral joint (TFJ) and their association with radiographic progression, using hypothesis free analyses.

DESIGN

205 patients from the GARP study with symptomatic OA at multiple sites (mean age 60 years, 80% woman, median BMI 26 kg/m(2)), underwent knee MRI at baseline. Cartilage damage, osteophytes, cysts, bone marrow lesions (BMLs) and effusion/synovitis were scored according to a validated scoring method. Baseline and 6-year TFJ and PFJ radiographs were scored (0-3) for JSN and osteophytes according to OARSI and Burnett atlases, respectively; progression was defined as ≥1 point increase. Baseline patterns of MRI abnormalities derived from principal component analysis (PCA) were associated with progression using adjusted generalized estimating equations (GEE).

RESULTS

PCA resulted in extraction of six components, explaining 69% of variance. In 29% and 29% of 133 patients with follow-up the TFJ progressed, whereas in 15% and 9% the PFJ progressed for osteophytes and JSN, respectively. Component 1 (cartilage damage of the PFJ and osteophytes of both joints) was statistically significant associated with TFJ JSN progression and PFJ osteophyte progression. Component 2 (all lateral PFJ abnormalities except osteophytes) was associated with JSN/osteophyte progression in the PFJ alone, whereas component 3 (all medial TFJ abnormalities except osteophytes) was associated with JSN and osteophyte progression in both PFJ and TFJ.

CONCLUSION

Baseline structural damage and bone turnover activity, as reflected by BMLs, seem to be involved in knee OA progression. Moreover, progression in PFJ and TFJ seems to be related.

Association of pain in knee osteoarthritis with distinct patterns of synovitis

OBJECTIVE

To determine possible patterns of synovitis on contrast-enhanced magnetic resonance imaging (CE-MRI) and its relation to pain and severity in patients with radiographic knee osteoarthritis (OA).

METHODS

In total, 86 patients (mean age 62 years, 66% women, median body mass index 29 kg/m(2) ) with symptomatic knee OA (Kellgren/Lawrence radiographic score 3) were included. T1-weighted, gadolinium-chelate-enhanced MRI with fat suppression was used to semiquantitatively score the extent of synovitis at 11 knee sites (total score range 0-22). Self-reported pain was assessed with 3 standardized questionnaires. Principal components analysis (PCA) was used to investigate patterns (the location and severity) of synovitis. Subsequently, these patterns were assessed for associations with pain measures and radiographic severity in adjusted logistic regression models.

RESULTS

Synovitis was observed in 86 patients and was found to be generally mild on CE-MRI (median total synovitis score 7, range 0-16). The median pain scores were 53 (range 0-96) on the visual analog scale for pain, 51.4 (range 2.8-97.2) on the Knee Injury and Osteoarthritis Outcome Score (KOOS) for pain, 35 (range 0-75) on the Intermittent and Constant Osteoarthritis Pain (ICOAP) score for constant pain, and 40.6 (range 0-87.5) on the ICOAP score for intermittent pain. PCA resulted in extraction of 3 components, explaining 53.4% of the variance. Component 1 was characterized by synovitis at 7 sites (mainly medial parapatellar involvement) and was associated with scores on the KOOS pain subscale and the ICOAP constant pain subscale. Component 2 was characterized by synovitis at 4 sites (mainly the site adjacent to the anterior cruciate ligament), but was not associated with pain measures or with radiographic severity. Component 3, characterized by synovitis at 3 sites (mainly at the loose body site), was associated with radiographic severity.

CONCLUSION

Different patterns of synovitis in knee OA were observed. The pattern that included several patellar sites was associated with pain, whereas other patterns showed no association, suggesting that pain perception in patients with knee OA is a localized response.

Degree of synovitis on MRI by comprehensive whole knee semi-quantitative scoring method correlates with histologic and macroscopic features of synovial tissue inflammation in knee osteoarthritis

OBJECTIVE

To evaluate the association between synovitis on contrast enhanced (CE) MRI with microscopic and macroscopic features of synovial tissue inflammation.

METHOD

Forty-one patients (mean age 60 years, 61% women) with symptomatic radiographic knee OA were studied: twenty underwent arthroscopy (macroscopic features were scored (0-4), synovial biopsies obtained), twenty-one underwent arthroplasty (synovial tissues were collected). After haematoxylin and eosin staining, the lining cell layer, synovial stroma and inflammatory infiltrate of synovial tissues were scored (0-3). T1-weighted CE-MRI's (3 T) were used to semi-quantitatively score synovitis at 11 sites (0-22) according to Guermazi et al. Spearman's rank correlations were calculated.

RESULTS

The mean (SD) MRI synovitis score was 8.0 (3.7) and the total histology grade was 2.5 (1.6). Median (range) scores of macroscopic features were 2 (1-3) for neovascularization, 1 (0-3) for hyperplasia, 2 (0-4) for villi and 2 (0-3) for fibrin deposits. The MRI synovitis score was significantly correlated with total histology grade [r = 0.6], as well as with lining cell layer [r = 0.4], stroma [r = 0.3] and inflammatory infiltrate [r = 0.5] grades. Moreover, MRI synovitis score was also significantly correlated with macroscopic neovascularization [r = 0.6], hyperplasia [r = 0.6] and villi [r = 0.6], but not with fibrin [r = 0.3].

CONCLUSION

Synovitis severity on CE-MRI assessed by a new whole knee scoring system by Guermazi et al. is a valid, non-invasive method to determine synovitis as it is significantly correlated with both macroscopic and microscopic features of synovitis in knee OA patients.

Magnetic resonance imaging of the hand joints in patients with inflammatory bowel disease and arthralgia: a pilot study

OBJECTIVES

To assess whether subclinical inflammatory changes are present on magnetic resonance imaging (MRI) in patients with inflammatory bowel disease (IBD) and arthralgia.

METHOD

In this pilot study, painful hand joints [metacarpophalangeal (MCP), proximal interphalangeal (PIP), and/or distal interphalangeal (DIP)] of 11 IBD patients (age 18-45 years) with continuous pain for > 6 weeks were scanned on a 1.5-T extremity MRI system. A control group of 11 IBD patients without joint pain who were matched for type and disease duration of IBD, gender, and age was included. All patients were clinically examined by a rheumatologist for the presence of pain and arthritis. Imaging was performed according to a standard arthritis protocol with intravenous contrast administration on the same day. Images (blinded for clinical information) were evaluated by two readers in consensus for the presence of joint fluid, synovitis, tenosynovitis, enthesitis, erosions, cartilage defects, and bone marrow oedema.

RESULTS

Enthesitis was seen in three hand joints (MCP 2, MCP 3, PIP 3) of 2/11 (18%) arthralgia patients and in none of the control group (p = 0.48). A small amount of subchondral bone marrow oedema was seen in the metacarpal head of two controls. No other abnormalities were observed.

CONCLUSIONS

Several young IBD patients with chronic hand pain had subclinical inflammation on MRI, which invites for further study in a larger group of patients.

Concordance between inflammation at physical examination and on MRI in patients with early arthritis

BACKGROUND

MRI is increasingly used to measure inflammation in rheumatoid arthritis (RA) research, but the correlation to clinical assessment is unexplored. This study determined the association and concordance between inflammation of small joints measured with MRI and physical examination.

METHODS

179 patients with early arthritis underwent a 68 tender joint count and 66 swollen joint count and 1.5T MRI of MCP (2-5), wrist and MTP (1-5) joints at the most painful side. Two readers scored synovitis and bone marrow oedema (BME) according to the OMERACT RA MRI scoring method and assessed tenosynovitis. The MRI data were first analysed continuously and then dichotomised to analyse the concordance with inflammation at joint examination.

RESULTS

1790 joints of 179 patients were studied. Synovitis and tenosynovitis on MRI were independently associated with clinical swelling, in contrast to BME. In 86% of the swollen MCP joints and in 92% of the swollen wrist joints any inflammation on MRI was present. In 27% of the non-swollen MCP joints and in 66% of the non-swollen wrist joints any MRI inflammation was present. Vice versa, of all MCP, wrist and MTP joints with inflammation on MRI 64%, 61% and 77%, respectively, were not swollen. BME, also in case of severe lesions, occurred frequently in clinically non-swollen joints. Similar results were observed for joint tenderness.

CONCLUSIONS

Inflammation on MRI is not only present in clinically swollen but also in non-swollen joints. In particular BME occurred in clinically non-inflamed joints. The relevance of subclinical inflammation for the disease course is a subject for further studies.

The value of magnetic resonance imaging in the differentiation between malignant peripheral nerve-sheath tumors and non-neurogenic malignant soft-tissue tumors

OBJECTIVE

To assess the sensitivity and specificity of MRI criteria in the differentiation between malignant peripheral nerve sheath tumors (MPNST) and non-neurogenic malignant soft-tissue tumors (MSTT).

DESIGN AND PATIENTS

MRI examinations of 105 patients with pathologically proven malignant soft-tissue lesions (35 MPNST and 70 MSTT) were retrospectively reviewed, the reviewers being unaware of the pathological diagnosis. Using a standardized protocol, the tumors were evaluated for multiple parameters regarding morphology and appearance on different sequences before and after gadolinium contrast administration (location, distribution, delineation, homogeneity, size, shape, relationship to bone and neurovascular bundle, intralesional hemorrhage, necrosis, perilesional edema, lymphangitis and signal intensities). Results were compared using a chi-square or Fisher's exact test.

RESULTS

MRI findings suggestive of MPNST (p<0,05) were intermuscular distribution, location on the course of a large nerve, nodular morphology, and overall non-homogeneity on T1-weighted images, T2-weighted images and T1-weighted images after gadolinium contrast injection. MRI findings in favor of MSTT were intramuscular distribution, ill-delineated appearance of more than 20% of the lesion's circumference, and presence of intralesional blood vessels, perilesional edema and lymphangitis. There is no significant difference for degree and pattern of enhancement after gadolinium contrast injection, nor for presence of bone involvement or cystic or necrotic areas.

CONCLUSION

MRI provides several features that contribute to the differentiation between MPNST and non-neurogenic malignant soft-tissue tumors. MRI findings suggestive of MPNST should be helpful to pathologists in the strategy for further examination.

Chondroid lipoma: findings on radiography and MRI (2006:7b)

We present a case of chondroid lipoma with various tumor components on MRI and ossified components on radiography. Information from both imaging modalities is required to make the correct diagnosis, and the role of radiography as a first choice imaging modality is highlighted.

Nora's lesion, a distinct radiological entity?

OBJECTIVE

To describe the radiological findings of "Bizarre parosteal osteochondromatous proliferation"(BPOP)-otherwise known as Nora's lesion, to describe the natural evolution of BPOP and to assess radiologically if BPOP is indeed part of a spectrum of reactive lesions including florid reactive periostitis and turret exostosis.

DESIGN

Four experienced musculoskeletal radiologists studied plain radiographs and other imaging documents of histologically-proven Nora's lesions, looking for soft-tissue changes, periosteal reaction/calcification and calcified/ossified pseudotumours, and compared those findings with findings on pathology reviewed by a peer group of pathologists.

PATIENTS

Twenty-four Nora's lesions originating from a series of 200 consecutive, histologically-verified bone (pseudo)tumours of the hand, seen by the "Netherlands Committee on Bone Tumours" for review and second opinion.

RESULTS

Nora's lesions have a recognised presentation on radiographs without specific MR characteristics. Natural evolution could be assessed retrospectively in four cases. Recurrent lesions were seen in seven cases and are difficult to differentiate from primary lesions.

CONCLUSIONS

Nora's lesion, defined as a "well-marginated mass of heterotopic mineralization arising from the periosteal aspect of an intact cortex, without medullary changes" has a distinct radiological presentation and is part of a spectrum of reactive lesions which includes florid reactive periostitis and turret exostosis. As it has a distinct radiological appearance, differential diagnosis of malignant lesions such as osteosarcoma and chondrosarcoma should be clear. It does not require immediate biopsy unless the natural evolution is unspecific.

Giant cell tumors of the tendon sheath may present radiologically as intrinsic osseous lesions

The purpose of this study was to explain radiographic features of giant cell tumors of the tendon sheath (GCTTS), in particular, osseous extension, by correlating imaging findings with histology in order to increase the accuracy of radiological diagnosis. In a series of 200 consecutive osseous (pseudo) tumors of the hand, on radiography, six patients presented with an intrinsic osseous lesion caused by a histologically confirmed neighboring GCTTS. Available radiographs, computed tomography (CT), and contrast-enhanced magnetic resonance (MR) images were correlated with histology. Radiography showed osseous lesions consisting of well-defined cortical defects in four (one of whom also demonstrated cortical scalloping) and a slightly expansile, well-defined osteolytic lesion in two patients. MR obtained in four patients showed the extraosseous tumor invading/eroding bone and causing cortical scalloping (three and one patients, respectively). Extension depicted on MR was confirmed on the two available resection specimens. All lesions were polylobular (cauliflower or mushroom like) and neighboring tendon sheaths. Dense collagen and hemosiderin-loaded macrophages explained the high CT attenuation and the low MR signal intensity on T2-weighted images that was observed in all four MR and in all two CT scans. The high density of proliferative capillaries explained the marked enhancement observed in all four patients with gadolinium (Gd)-chelate-enhanced MR imaging. GCTTS is a soft tissue (pseudo) tumor that may invade bone and as a consequence mimick an intrinsic osseous lesion on radiographs. In such cases, specific MR and CT features that can be explained by histological findings can be used to suggest the correct diagnosis.

Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors

The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), "brown tumor" (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma "not otherwise specified" (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.

Accuracy of radiography in grading and tissue-specific diagnosis--a study of 200 consecutive bone tumors of the hand

OBJECTIVE

To determine the usefulness of radiography and magnetic resonance imaging in differentiating benign from malignant bony tumors of the hand and in making a tissue-specific diagnosis.

DESIGN

Two hundred consecutive bony tumors of the hand, the details of which originated from a national databank, were studied in a prospective way by radiography (100%) and by MRI (25%). All tumors were graded on a five-point scale, from certainly benign to certainly malignant, using location and morphology as diagnostic parameters. For all tumors a tissue-specific diagnosis was made, by the proposal of three possibilities in decreasing order of probability. Histological diagnosis was made by peer review, according to the WHO classification.

RESULTS

By the combining of "certainly" and "probably" benign (grades I and II) and "certainly" and "probably" malignant (grades IV and V), a correct grading was obtained in 165 (82.5%) of the cases (154 of the 173 benign and 11 of the 27 malignant tumors). A correct tissue-specific diagnosis was included in the three proposed differentials in 87.5%. MRI confirmed a correct diagnosis made on radiography in 72% and improved the grading capability by correctly upgrading malignant tumors and downgrading benign tumors in, respectively, 8% and 12%. The capability to obtain a tissue-specific diagnosis improved with change of an incorrect diagnosis on radiography to a correct one on MRI in 12 cases (24%).

CONCLUSION

Subjective (semiquantitative) grading on radiography by an expert group proved to be excellent when compared with the results of a quantitative analysis of individual grading parameters. Multiple logistic regression analysis of these parameters resulted in a grading formula containing only six variables. The additional value of MRI in grading was amply demonstrated. Already high accuracy of radiography, in making a tissue-specific diagnosis, improved substantially after the performance of MRI.

Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism

OBJECTIVE

A clinical diagnosis of pulmonary embolism (PE) is confirmed objectively in 20-30% of patients. Helical computed tomography (CT) can allow an alternative diagnosis to be made. The frequency and validity of alternative diagnoses on helical CT in consecutive patients presenting with clinically suspected PE was assessed.

PATIENTS AND METHODS

In all 512 prospectively analyzed patients helical CT scan was performed, and apart from presence or absence of PE, pathologic changes in lung parenchyma, mediastinum, cardiovascular system, pleura and skeleton were recorded. When possible an alternative diagnosis was given and compared with the final diagnosis after 3 months follow-up.

RESULTS

In 130 patients (25.4%) PE was excluded and an alternative diagnosis considered likely. In 123 of the 130 patients (94.6%) this diagnosis was unchanged at 3 months follow-up. The diagnoses included pneumonia (n = 67), malignancy (n = 22), pleural fluid (n = 10), cardiac failure (n = 10), COPD (n = 6) and a variety of other causes (n = 15). The diagnosis changed at follow-up in seven patients (5.4%). An initial diagnosis of pneumonia changed to malignancy in two patients and to pleuritis and cardiac failure in one patient each. In two other patients malignancy and chronic obstructive pulmonary disease (COPD) were ruled out and the diagnosis changed to pneumonia. In one patient the final diagnosis remained unknown after an initial suspicion of malignancy.

CONCLUSION

In clinically suspected PE helical CT allows a reliable alternative diagnosis to be made in 25.4% of patients. This feature is an unique advantage in comparison with other diagnostic tests and supports the decision of taking helical CT as first line test in suspected PE.

Neurologic dysfunction in patients with rheumatoid arthritis of the cervical spine. Predictive value of clinical, radiographic and MR imaging parameters

The aim of this study was to evaluate if subjective symptoms, radiographic and especially MR parameters of cervical spine involvement, can predict neurologic dysfunction in patients with severe rheumatoid arthritis (RA). Sequential radiographs, MR imaging, and neurologic examination were performed yearly in 46 consecutive RA patients with symptoms indicative of cervical spine involvement. Radiographic parameters were erosions of the dens or intervertebral joints, disc-space narrowing, horizontal and vertical atlantoaxial subluxation, subluxations below C2, and the diameter of the spinal canal. The MR features evaluated were presence of dens and atlas erosion, brainstem compression, subarachnoid space encroachment, pannus around the dens, abnormal fat body caudal to the clivus, cervicomedullary angle, and distance of the dens to the line of McRae. Muscle weakness was associated with a tenfold increased risk of neurologic dysfunction. Radiographic parameters were not associated. On MR images atlas erosion and a decreased distance of the dens to the line of McRae showed a fivefold increased risk of neurologic dysfunction. Subarachnoid space encroachment was associated with a 12-fold increased risk. Rheumatoid arthritis patients with muscle weakness and subarachnoid space encroachment of the entire cervical spine have a highly increased risk of developing neurologic dysfunction.

MR features of peripheral nerve sheath tumors: can a calculated index compete with radiologist's experience?

The aims of this study were, firstly, to provide a formula (neurogenic index) based on MR characteristics used in daily routine for predicting whether a soft tissue tumor is neurogenic or not, secondly, to test prospectively the performance of this formula, and thirdly, to compare this performance with that of radiologists experienced in MR imaging of soft tissue tumors. Retrospectively, MR images of 70 neurogenic and 70 non-neurogenic soft tissue tumors were evaluated in random order by two teams of two observers each. A neurogenic index (NI) was calculated based on those MR parameters that showed no or minor interobserver variability. Subsequently, three investigators in concert used the NI in a validation group of 15 neurogenic and 22 nonneurogenic soft tissue tumors. The same team, based on their own experience, tried to differentiate in the same validation group neurogenic from non-neurogenic soft tissue tumors. This was expressed in a subjective score (SS). Sensitivity, specificity, and predictive values were calculated. NI comprised spread (intra- or extracompartmental), distribution, fluid-fluid levels, homogeneity on T2-weighted images (WI), highest signal intensity (SI) on T1WI, lowest SI on T2WI, and delineation on T2WI. In the validation group, NI had a sensitivity of 88.6%, a specificity of 52.0%, a positive predictive value (PPV) of 54.1%, and a negative predictive value (NPV) of 84.6% for neurogenic tumors. The subjective score SS was superior and had a sensitivity of 93.3%, a specificity of 77.2%, a PPV of 73.7%, and a NPV of 94.4%. Our NI was less accurate than the SS; however, the low number of false-negative diagnoses for neurogenic tumors warrants continued efforts in development of neural networks.

Synovial sarcoma: dynamic contrast-enhanced MR imaging features

OBJECTIVE

To determine whether previously described so-called malignant dynamic contrast-enhanced magnetic resonance (MR) imaging features--early start, peripheral enhancement and early plateau or washout phase--occur consistently in synovial sarcoma.

DESIGN AND PATIENTS

Dynamic contrast-enhanced MR images of 10 patients with histologically proven synovial sarcoma were reviewed. The start, pattern and progression of tumor enhancement were assessed and correlated with histopathology.

RESULTS

In all patients, the time interval between arterial and early tumor enhancement was less than 7 s (mean 4.40 s, SD 2.09 s). Six synovial sarcomas showed enhancement with a subsequent rapidly progressive linear increase in signal intensity followed by a plateau in one lesion and washout in five. Four lesions showed a late sustained increase in enhancement after the initial rapid increase in enhancement. The pattern of initial enhancement was peripheral in only two lesions, diffuse in four and heterogeneous in four lesions.

CONCLUSIONS

Enhancement of tumor within 7 s after arterial enhancement is, of the three parameters described previously, the only sign that occurs consistently in synovial sarcoma.

Detection of areas with viable remnant tumor in postchemotherapy patients with Ewing's sarcoma by dynamic contrast-enhanced MRI using pharmacokinetic modeling

An approach is presented for monitoring the effects of neoadjuvant chemotherapy in patients with Ewing's sarcoma using dynamic contrast-enhanced perfusion magnetic resonance (MR) images. For that purpose, we modify the three-compartment pharmacokinetic permeability model introduced by Tofts et al. (Magn Reson Med 1991;17:357-67) to a two-compartment model. Perfusion MR images acquired using an intravenous injection with Gadolinium (Gd-DTPA) are analyzed with this two-compartment pharmacokinetic model as well as the with an extended pharmacokinetic model that includes the (local) arrival time t(0) of the tracer as an endogenous (estimated) parameter. For each MR section, a wash-in parameter associated with each voxel is estimated twice by fitting each of the two pharmacokinetic models to the dynamic MR signal. A comparison of the two wash-in parametric images (global versus local arrival time) with matched histologic macroslices demonstrates a good correspondence between areas with viable remnant tumor and a high wash-in rate. This can be explained by the high number and permeability of the (leaking) capillaries in viable tumor tissue. The novel pharmacokinetic model based on a local arrival time of tracer results in the best fit of the wash-in rate, the most important factor discerning viable from nonviable tumor components. However, parameter estimates obtained with this model are also more sensitive to noise in the MR signal. The novel pharmacokinetic model resulted in a sensitivity between 0.22 and 0.60 and a specificity between 0.61 and 1. The model based on a global arrival time gave sensitivities between 0.33 and 0.77 and specificities between 0.58 and 0.99. Both statistics are computed as the fraction of correctly labeled voxels (viable or nonviable tumor) within a specified ROI, which delineates the tumor. We conclude that the added value of estimating the local arrival time of tracer first manifests itself for moderate noise levels in the MR signal. The novel pharmacokinetic model should moreover be preferred when pharmacokinetic modeling is applied on the average signal intensity within a ROI, where noise has less effect on the fitted parameters.

Focal liver lesions: evaluation of the efficacy of gadobenate dimeglumine in MR imaging--a multicenter phase III clinical study

PURPOSE

To evaluate gadobenate dimeglumine (Gd-BOPTA) for dynamic and delayed magnetic resonance (MR) imaging of focal liver lesions.

MATERIALS AND METHODS

In 126 of 214 patients, MR imaging was performed before Gd-BOPTA administration, immediately after bolus administration of a 0.05- mmol/kg dose of Gd-BOPTA, and 60-120 minutes after an additional intravenously infused 0.05-mmol/kg dose. In 88 patients, imaging was performed before and 60-120 minutes after a single, intravenously infused 0.1-mmol/kg dose. T1- and T2-weighted spin-echo and T1-weighted gradient-echo images were acquired. On-site and blinded off-site reviewers prospectively evaluated all images. Intraoperative ultrasonography, computed tomography (CT) during arterial portography, and/or CT with iodized oil served as the reference methods in 110 patients.

RESULTS

Significantly more lesions were detected on combined pre- and postcontrast images compared with on precontrast images alone (P <. 01). All reviewers reported a decreased mean size of the smallest detected lesion and improved lesion conspicuity on postcontrast images. All on-site reviewers and two off-site reviewers reported increased overall diagnostic confidence (P <.01). Additional lesion characterization information was provided on up to 109 (59%) of 184 delayed images and for up to 50 (42%) of 118 patients in whom dynamic images were assessed. Gd-BOPTA would have helped change the diagnosis in 99 (47%) of 209 cases and affected patient treatment in 408 (23%) of 209 cases.

CONCLUSION

Gd-BOPTA increases liver lesion conspicuity and detectability and aids in the characterization of lesions.

MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): a multicenter correlative MRI-pathology study of 21 cases and literature review

OBJECTIVE

To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts).

DESIGN AND PATIENTS

MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study.

RESULTS

On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody.

CONCLUSIONS

Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well-defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images.

Bone tumors

We present an overview of the imaging modalities in bone tumors. The imaging strategies of preoperative work-up, monitoring the effect of chemotherapy and the detection of recurrences by long-term follow-up are discussed.

Cartilaginous tumors: fast contrast-enhanced MR imaging

PURPOSE

To differentiate between benign and malignant cartilaginous tumors with fast contrast material-enhanced magnetic resonance (MR) imaging.

MATERIALS AND METHODS

In 37 patients, fast contrast-enhanced MR images were obtained in eight enchondromas, 11 osteochondromas, and 18 chondrosarcomas. Start of enhancement-early, within 10 seconds after arterial enhancement; delayed, between 10 seconds and 2 minutes; late, after 5 minutes on spin-echo images-and progression of enhancement were represented with three types of time-signal intensity curves. Findings were correlated with the surgical specimen in 27 cases, curettage material in three cases, and biopsy combined with long-term follow-up findings in seven cases.

RESULTS

Start of enhancement and the combination of start and progression of enhancement correlated significantly (P <.001) with benign and malignant tumors. Early enhancement was seen in chondrosarcoma, not seen in enchondroma, and seen in osteochondroma only when growth plates were unfused. The sensitivity was 89%, specificity 84%, positive predictive value 84%, and negative predictive value 89%. Differentiation of malignancy from benignity on the basis of early and exponential enhancement was possible with a sensitivity of 61%, specificity 95%, positive predictive value 92%, and negative predictive value 72%.

CONCLUSION

Preliminary results show that in the adult population fast contrast-enhanced MR imaging may assist in differentiation between benign and malignant cartilaginous tumors.

Are magnetic resonance flexion views useful in evaluating the cervical spine of patients with rheumatoid arthritis?

OBJECTIVE

To determine whether MR imaging in flexion adds value relative to imaging in the neutral position with respect to displaying involvement of the subarachnoid space, brainstem and spinal cord.

DESIGN AND PATIENTS

T1-weighted MR images of the cervical spine in 42 rheumatoid arthritis patients with cervical spine involvement were obtained and analyzed prospectively. We assessed changes between images obtained in the neutral position and following active flexion, especially horizontal atlantoaxial and subaxial motion, presence or absence of brainstem compression, subarachnoid space involvement at the atlantoaxial and subaxial level and the cervicomedullary angle. Vertical atlantoaxial subluxation and the amount of pannus were correlated with motion and change in subarachnoid space.

RESULTS

The flexion images showed horizontal atlantoaxial motion in 21 patients and subaxial motion in one patient. The flexion view displayed brainstem compression in only one patient. Involvement of the subarachnoid space increased at the atlantoaxial level in eight (19%) patients (P=0.004) and at the level below C2 in five (12%) patients (P=0.03). There were no patients with a normal subarachnoid space in neutral position and compression in the flexed position. The cervicomedullary angle changed significantly with flexion. Vertical atlantoaxial subluxation and the amount of pannus did not show a significant correlation with motion or subarachnoid space involvement.

CONCLUSION

MR imaging in the flexed position shows a statistically significant narrowing of the subarachnoid space at the atlantoaxial level and below C2. Cord compression is only observed on flexion views if the subarachnoid space in neutral position is already decreased. MR imaging in the flexed position might be useful, since subarachnoid space involvement may be an indicator for the development of neurologic dysfunction.

MRI of liver metastases: limitation of spleen-liver model in optimizing pulse sequences

The spleen-liver model, as a predictor for contrast-to-noise ratio (C/N) in liver metastases, was verified for seven sequences in 22 patients with 70 colorectal metastases. Optimization of conventional spin-echo, T1-magnetization-prepared gradient-echo and fat frequency-selective presaturation inversion-recovery fast spin echo can be done using the spleen-liver model. C/N of liver-spleen and liver-metastases, however, differed significantly on our T1 gradient-echo and T2-weighted fast spin-echo images, with and without fat-selective saturation.

Somatic effects in nuclear medicine and radiology

Probable risks for the occurrence of somatic effects due to diagnostic radiology and nuclear medicine are summarised. The biological background of radiation carcinogenesis and epidemiological results are discussed. At the Leiden University Medical Centre the average effective dose per examination due to diagnostic radiology and nuclear medicine amount to 0.95 and 4.4 mSv, respectively. These values correspond well with the average values of 0.82 and 3.0 mSv reported for The Netherlands as a whole. Since radiological examinations are performed at a much larger frequency than nuclear medicine the relative collective dose for the first type of examinations is higher than the latter. Risk for occurency of malignancies are at least one order of magnitude lower than the hypothetical risk due to the background radiation typical of The Netherlands.

Comparison of inversion-recovery gradient- and spin-echo and fast spin-echo techniques in the detection and characterization of liver lesions

PURPOSE

To compare respiratory-triggered inversion-recovery (IR) gradient- and spin-echo (GRASE) magnetic resonance (MR) imaging with respiratory-triggered T2-weighted fast spin-echo (SE) imaging in the diagnosis of liver metastases.

MATERIALS AND METHODS

In this prospective study, two radiologists independently identified focal hepatic lesions on respiratory-triggered IR GRASE and respiratory-triggered fast SE MR images in 28 consecutive patients with 186 (135 malignant and 51 benign) proved lesions. A combination of findings at surgery, intraoperative ultrasonography (US), and histologic examination served as the standard of reference. Contrast-to-noise ratios (CNRs) were obtained from 86 lesions larger than 10 mm.

RESULTS

The sensitivity in the detection of liver metastases was, independent of lesion size and observer, higher for IR GRASE imaging (55%) than for fast SE imaging (44%-50%) (observer 1, P = .014; observer 2, P = .21). Confidence levels with IR GRASE imaging were higher, but not significantly so, than those with fast SE imaging (P < .098). Both observers characterized liver lesions better with IR GRASE than with fast SE imaging (observer 1, P = .04; observer 2, P = .48). The metastasis-liver CNR was significantly higher (P = .012) with IR GRASE imaging.

CONCLUSION

The respiratory-triggered IR GRASE sequence is a fast alternative to the respiratory-triggered fast SE sequence in the evaluation of suspected liver metastases.

Posterior labrocapsular periosteal sleeve avulsion complicating locked posterior shoulder dislocation

This case presents the imaging features of a posterior shoulder dislocation complicated by a rare but surgically relevant lesion of the posterior labrum. Due to the attachment of the posterior capsule to the posterior portion of the labrum, which in itself is attached to the posterior scapular periosteum, stripping of the labrum by the posterior capsule resulted in a posterior labrocapsular periosteal sleeve avulsion.

Musculoskeletal tumors: does fast dynamic contrast-enhanced subtraction MR imaging contribute to the characterization?

PURPOSE

To prospectively analyze the value of fast, dynamic, subtraction magnetic resonance (MR) imaging in the characterization of musculoskeletal tumors.

MATERIALS AND METHODS

In 175 consecutive patients with a musculoskeletal mass, dynamic contrast-enhanced subtraction MR imaging was performed after administration of 0.1 mmol per kilogram of body weight gadopentetate dimeglumine or gadoteridol. A turbo gradient-echo technique was used, with a temporal resolution of 1-3 seconds. The interval between arterial and early tumor enhancement, the pattern (peripheral or diffuse) of enhancement, and the progression of tumor enhancement, as visualized on time-signal intensity curves, were assessed. MR enhancement features were related to the histopathologic diagnoses.

RESULTS

Differentiation of benign from malignant soft-tissue masses was possible with a sensitivity of 91% and specificity of 72% based on start of enhancement, a sensitivity of 73% and specificity of 97% based on peripheral or diffuse enhancement, and a sensitivity of 86% and specificity of 81% based on progression of enhancement. Benign bone tumors could not be accurately differentiated from malignant bone tumors on the basis of the three defined parameters (sensitivity, 63%-76%; specificity, 50%-76%).

CONCLUSION

Dynamic, contract-enhanced, subtraction MR images may be useful to differentiate malignant from benign soft-tissue masses.

Tarsal navicular relations in club foot: is there a role for magnetic resonance imaging?

OBJECTIVE

To correlate radiographic and MR appearances with surgical findings to determine the accuracy of these modalities in demonstrating tarsal navicular (TN) relations in order to select the appropriate surgical intervention.

DESIGN AND PATIENTS

Fourteen consecutive patients with 19 club feet had anteroposterior and lateral radiographs and magnetic resonance (MR) imaging performed. Blinded retrospective interpretation of these studies was correlated with surgical findings. Movement artifact was responsible for initial non-diagnostic MR scans in 3 out of 19 feet.

RESULTS

Plain radiographs and MR imaging had sensitivities of 79% and 84% respectively for TN subluxation, while both modalities had 100% positive predictive value for TN subluxation. Each modality produced indeterminate results in cases where subluxation was present at surgery, but in combination there were no false negatives.

CONCLUSION

Radiography confidently predicted the TN alignment in the majority of cases. MR demonstrated TN relationships in all cases where radiography was indeterminate. It is proposed that MR has a potential role to demonstrate TN relationships when radiography is indeterminate or when there is disparity between the clinical and radiographic assessment.