Detektion und quantitative Analyse von entzündlichen und strukturellen Veränderungen im Vergleich zur MRT

Die Magnetresonanztomographie (MRT) ist ein etabliertes Verfahren in der Arthritisdiagnostik. Entzündliche Veränderungen können dargestellt und mittels dynamischer kontrastverstärkter MRT (DCE-MRT) auch quantitativ bewertet werden. Bei der differenzierten Bewertung von strukturellen Veränderungen im Rahmen der rheumatoiden Arthritis besitzt die MRT jedoch eine geringe Spezifität. Dagegen zeigt die Computertomographie (CT) deutliche Vorteile bei der Detektion von knöchernen Läsionen. Die Durchführbarkeit der CT in der Detektion von entzündlichen Veränderungen ist daher Gegenstand der aktuellen Forschung. Zielsetzung: Ziel dieser Arbeit war es den diagnostischen Stellenwert der kontrastverstärkten CT in der Arthritisbildgebung zu untersuchen. Die Durchführbarkeit der CT-Subtraktion wurde in der Detektion von entzündlichen Veränderungen evaluiert und mittels quantitativer Analyse der Perfusion in der dynamischen kontrastverstärkten CT (DCE-CT) und DCE-MRT nachgewiesen. Ein Teilaspekt der Auswertung war die suszeptibilitätsgewichtete Sequenz (SWI) für die Erosiondetektion. Methoden: 37 Patienten mit Verdacht oder gesicherter rheumatoiden Arthritis der Hand wurden prospektiv in der kontrastverstärkten ultra-niedrigdosierten CT und MRT untersucht. Aus den gewonnenen CT-Bilddaten wurde zur Darstellung von Synovialitis und Tenosynovialitis die CT-Subtraktion berechnet und mit der MRT als Referenz verglichen. Durch Berechnung der Perfusionsparameter aus der DCE-CT und DCE-MRT wurde die Perfusion quantitativ zwischen den beiden Modalitäten verglichen. Das MRT-Protokoll beinhaltete zusätzlich zum Standardprotokoll eine SWI Sequenz. Die Bewertung der Erosion, Synovialitis und Tenosynovialitis fand durch drei Bewerter nach den etablierten Rheumatoid Arthritis Magnetic Resonance Scores (RAMRIS) Kriterien statt. Ergebnisse: Die CT-Subtraktion erzielte in der Detektion von Synovialitis eine Spezifität von 88%. Es wurde eine gute Korrelation zwischen der CT-Subtraktion und der MRT gezeigt (Pearson’s r = 0,94). Zusätzlich waren die Perfusionsparameter in beiden Modalitäten vergleichbar. Mittels DCE-CT konnte zudem die Entzündungsaktivität differenziert werden. Die SWI führte zu einer verbesserten Darstellbarkeit von Erosionen im Vergleich oder in Ergänzung zu herkömmlichen Sequenzen. Schlussfolgerung: Die CT-Perfusion stellt in der Arthritisbildgebung eine neue Modalität dar, die mit einer hohen Sicherheit entzündliche Veränderungen an Gelenken, sowie an Sehnenscheiden abbilden kann und ebenso auf quantitativer Ebene mit der DCE-MRT vergleichbare Perfusionsanalyse liefert. Zusätzlich ist sie als Goldstandard in der Detektion von knöchernen Läsionen bisher nicht zu übertreffen.Magnetic resonance imaging (MRI) is an established imaging modality in the field of arthritis imaging. Inflammatory lesions can be detected and also quantitatively assessed using dynamic contrast-enhanced MRI (DCE-MRI). However, MRI has a low specificity in the differentiated assessment of structural changes in the context of rheumatoid arthritis. In contrast, computed tomography (CT) shows obvious advantages in the detection of bony lesions. The feasibility of CT in the detection of inflammatory lesions is therefore the subject of current research. Objective: The aim of this work was to investigate the diagnostic importance of contrastenhanced CT in arthritis imaging. The feasibility of CT-subtraction in the detection of inflammatory lesions was evaluated and demonstrated by quantitative analysis of the perfusion using dynamic contrast-enhanced CT (DCE-CT) and DCE-MRI. A partial aspect was to evaluate the use of the susceptibility-weighted imaging sequence (SWI) in erosion detection. Methods: 37 patients with suspected or proven diagnosis of rheumatoid arthritis of the hand prospectively underwent contrast-enhanced ultra-low-dose CT and MRI. CTsubtraction was calculated from the obtained CT image data to represent synovitis and tenosynovitis and compared with MRI as a reference. By assessing the perfusion parameters using DCE-CT and DCE-MRI, the perfusion was compared quantitatively between these two modalities. In addition to standard protocol, the MRI protocol included the SWI sequence. The evaluation of erosion, synovitis and tenosynovitis was performed by three readers according to the established Rheumatoid Arthritis Magnetic Resonance Scores (RAMRIS) criteria. Results: CT-subtraction performed with a specificity of 88% in detection of synovitis. There was shown a good correlation between CT-subtraction and MRI (Pearson’s r = 0,94). In addition, the perfusion parameters were comparable in both modalities. Inflammatory activity was also differentiated using DCE-CT. The SWI let to an improved detection of erosions compared to or in addition to conventional sequences. Conclusion: CT-perfusion represents a new modality in arthritis imaging, which can detect inflammation of the joints and tendons with a high degree of certainty and also provides a quantitative perfusion analysis comparable to that of DCE-MRI. In addition, CT has so far not been surpassed as the gold standard in the detection of bony lesions

Four-dimensional computed tomography detects dynamic three-dimensional pathologies of the wrist in patients with calcium pyrophosphate deposition disease

ObjectivesCrystal deposits in ligaments of the wrist are typical findings in patients with calcium pyrophosphate deposition (CPPD) disease. CPPD crystals trigger inflammation and ultimately result in ligament tears with scapholunate (SL) advanced collapse (SLAC). This study aimed to investigate carpal instabilities in patients with CPPD using four-dimensional computed tomography (4D-CT) of the wrist.MethodsThis IRB-approved prospective feasibility study investigated patients with CPPD of the hand. All patients underwent a static 3D-CT and two dynamic 4D-CT in ulnar- and radial abduction and in supination and pronation movements to analyze instabilities of the SL region and of the distal radioulnar joint (DRUJ). Two independent readers scored the images for the presence of SL ligament and triangular fibrocartilage complex (TFCC) calcifications. Furthermore, the readers assessed the dynamic images for SL and DRUJ instabilities. Descriptive analyses were performed. Inter-rater reliability was assessed using Cohen’s kappa (κ).ResultsNine patients were included. SL ligament calcifications and instabilities were found in all patients. Of these, dynamic SL instability was detected in 77.8% of the patients, while 22.2% had a SLAC wrist. TFCC calcifications were found in 87.5% of the patients. Four patients had DRUJ instability (50%). No patient showed DRUJ instability without the presence of TFCC calcifications. Agreement between readers for calcifications was excellent (κ = 1) and almost perfect (κ = 0.89) for instabilities.ConclusionThis study provides the first evidence of relevant dynamic carpal instability in CPPD patients using advanced imaging techniques with 4D-CT, offering unique insights into wrist biomechanics

Perfusion in hand arthritis on dynamic contrast-enhanced computed tomography: a randomized prospective study using MRI as a standard of reference

Objective: To evaluate the performance of dynamic contrast-enhanced CT (DCE-CT) in detecting and quantitatively assessing perfusion parameters in patients with arthritis of the hand compared with dynamic contrast-enhanced MRI (DCE-MRI) as a standard of reference. Materials and methods: In this IRB-approved randomized prospective single-centre study, 36 consecutive patients with suspected rheumatoid arthritis underwent DCE-CT (320-row, tube voltage 80 kVp, tube current 8.25 mAs) and DCE-MRI (1.5 T) of the hand. Perfusion maps were calculated separately for mean transit time (MTT), time to peak (TTP), relative blood volume (rBV), and relative blood flow (rBF) using four different decomposition techniques. Region of interest (ROI) analysis was performed in metacarpophalangeal joints II–V and in the wrist. Pairs of perfusion parameters in DCE-CT and DCE-MRI were compared using a two-tailed t test for paired samples and interpreted for effect size (Cohen’s d). According to the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) scoring results, differentiation of synovitis-positive and synovitis-negative joints with both modalities was assessed with the independent t test. Results: The two modalities yielded similar perfusion parameters. Identified differences had small effects (d 0.01–0.4). DCE-CT additionally differentiates inflamed and noninflamed joints based on rBF and rBV but tends to underestimate these parameters in severe inflammation. The total dose-length product (DLP) was 48 mGy*cm with an estimated effective dose of 0.038 mSv. Conclusion: DCE-CT is a promising imaging technique in arthritis. In patients with a contraindication to MRI or when MRI is not available, DCE-CT is a suitable alternative to detect and assess arthritis

Sex Disparities of the Sacroiliac Joint: Focus on Joint Anatomy and Imaging Appearance

The sacroiliac joint (SIJ) is an anatomically complex joint which, as a functional unit with the pelvis and spine, is of decisive biomechanical importance for the human body. It is also a commonly overlooked source of lower back pain. Like the entire bony pelvis, the SIJ exhibits major sexual dimorphisms; thus, the sex-dependent evaluation of this joint is becoming increasingly important in clinical practice, both anatomically with joint shape variations and biomechanical differences as well as in terms of image appearance. The influence of the SIJ shape, which differs in women and men, is crucial for the different biomechanical joint properties. These differences are important in the development of joint diseases at the SIJ, which shows a specific difference between the sexes. This article aims to provide an overview of sex disparities of the SIJ regarding different anatomical and imaging appearances to further understand the insights into the interplay of sex differences and SIJ disease

Sex Disparities of the Sacroiliac Joint: Focus on Joint Anatomy and Imaging Appearance

The sacroiliac joint (SIJ) is an anatomically complex joint which, as a functional unit with the pelvis and spine, is of decisive biomechanical importance for the human body. It is also a commonly overlooked source of lower back pain. Like the entire bony pelvis, the SIJ exhibits major sexual dimorphisms; thus, the sex-dependent evaluation of this joint is becoming increasingly important in clinical practice, both anatomically with joint shape variations and biomechanical differences as well as in terms of image appearance. The influence of the SIJ shape, which differs in women and men, is crucial for the different biomechanical joint properties. These differences are important in the development of joint diseases at the SIJ, which shows a specific difference between the sexes. This article aims to provide an overview of sex disparities of the SIJ regarding different anatomical and imaging appearances to further understand the insights into the interplay of sex differences and SIJ disease

HLA-B27 status and inflammatory MRI lesions of the sacroiliac joints: a post hoc analysis in patients without axial spondyloarthritis

Objective The assessment of inflammatory and structural lesions in the sacroiliac joint (SIJ) is crucial in axial spondyloarthritis (axSpA). HLA-B27 status plays an important role in axSpA diagnosis and has been linked to MRI lesion burden in the general population. We aimed to investigate the sex-specific influence of HLA-B27 status on inflammatory and structural MRI findings in patients with low back pain of non-inflammatory origin.Methods This post hoc analysis included 139 non-axSpA patients (90 women) with chronic low back pain. Two readers scored MRIs of the SIJ for the presence of sclerosis, erosion, fat metaplasia, bone marrow oedema (BMO) and ankylosis. Frequencies and extent of lesions were compared regarding the HLA-B27 status using χ2 tests and t-tests. Regression models to assess the sex-dependent influence of HLA-B27 on lesion burden were computed.Results HLA-B27 was positive in 33 women (36.7%) and 23 men (46.9%). The overall occurrence of all SIJ lesions did not differ in HLA-B27 negative and positive individuals. There were no significant differences in the extent of lesions considering the HLA-B27 positivity, for erosion (mean sum score (MSS) of 0.91 vs 0.48; p=0.144), sclerosis (MSS 1.65 vs 1.88; p=0.576), fat metaplasia (MSS 0.56 vs 0.27; p=0.425), BMO (MSS 0.75 vs 0.59; p=0.460) and ankylosis (MSS 0.06 vs 0.04; p=0.659).Conclusion HLA-B27 status has no significant influence on the occurrence and extent of SIJ lesions in patients with low back pain of non-inflammatory origin in either men or women

Virtual Monochromatic Images from Dual-Energy Computed Tomography Do Not Improve the Detection of Synovitis in Hand Arthritis

The objective of this study was to investigate subtraction images from different polychromatic and virtual monochromatic reconstructions of dual-energy computed tomography (CT) for the detection of inflammation (synovitis/tenosynovitis or peritendonitis) in patients with hand arthritis. In this IRB-approved prospective study, 35 patients with acute hand arthritis underwent contrast-enhanced dual-energy CT and musculoskeletal ultrasound (MSUS) of the clinically dominant hand. CT subtractions (CT-S) were calculated from 80 and 135 kVp source data and monochromatic 50 and 70 keV images. CT-S and MSUS were scored for synovitis and tenosynovitis/peritendonitis. Specificity, sensitivity and diagnostic accuracy were assessed by using MSUS as a reference. Parameters of objective image quality were measured. Thirty-three patients were analyzed. MSUS was positive for synovitis and/or tenosynovitis/peritendonitis in 28 patients. The 70 keV images had the highest diagnostic accuracy, with 88% (vs. 50 keV, 82%; 80 kVp, 85%; and 135 kVp, 82%), and superior sensitivity, with 96% (vs. 50 keV: 86%, 80 kVp: 93% and 135 kVp: 79%). The 80 kVp images showed the highest signal- and contrast-to-noise ratio, while the 50 keV images provided the lowest image quality. While all subtraction methods of contrast-enhanced dual-energy CT proved to be able to detect inflammation with sufficient diagnostic accuracy, virtual monochromatic images with low keV showed no significant improvement over conventional subtraction techniques and lead to a loss of image quality

Dual-Energy Computed Tomography Collagen Density Mapping of the Cranio-Cervical Ligaments—A Retrospective Feasibility Study

The objectives of this study were to investigate the mean collagen content of the atlanto-axial joint (AAJ) ligaments in a cohort without inflammatory disease and to analyze clinical confounders such as age, sex, and presence of ligamentous calcifications. A total of 153 patients who underwent dual-energy computed tomography (DECT) due to various reasons (e.g., suspected cancer or infection) were included in this retrospective study. Reconstruction of collagen density maps from the DECT dataset was performed. Region of interest (ROI) analysis was performed to assess densities in the following regions: ligamentum transversum atlantis (LTA), ligamenta alaria, fasciculi longitudinales, ligamentum nuchae, and retro-odontoid soft tissue (RDS). Osteoarthritis (OA) and the presence of calcifications were assessed by two experienced readers blinded to clinical data. Subgroup comparisons were performed using unpaired t-tests. The correlation of collagen density and clinical factors was investigated using Pearson’s correlation coefficient. Mean LTA collagen density was 141.7 (SD 35.7). Ligamentous calcifications were rare (14.4 %). OA of the AAJ was common (91.5 %). LTA collagen density was not associated with age (Pearson’s r of 0.109; p = 0.180) and was not significantly higher in patients with OA (p = 0.070). No correlations between RDS thickness, collagen density or calcifications were found. Our results show collagen density mapping of the cranio-cervical joint ligaments to be feasible; collagen densities are not significantly associated with age, sex, AAJ degeneration, or asymptomatic ligamentous calcification

Sex-specific diagnostic efficacy of MRI in axial spondyloarthritis: challenging the ‘One Size Fits All’ notion

Objectives Sex-specific differences in the presentation of axial spondyloarthritis (axSpA) may contribute to a diagnostic delay in women. The aim of this study was to investigate the diagnostic performance of MRI findings comparing men and women.Methods Patients with back pain from six different prospective cohorts (n=1194) were screened for inclusion in this post hoc analysis. Two blinded readers scored the MRI data sets independently for the presence of ankylosis, erosion, sclerosis, fat metaplasia and bone marrow oedema. Χ2 tests were performed to compare lesion frequencies. Contingency tables were used to calculate markers for diagnostic performance, with clinical diagnosis as the standard of reference. The positive and negative likelihood ratios (LR+/LR–) were used to calculate the diagnostic OR (DOR) to assess the diagnostic performance.Results After application of exclusion criteria, 526 patients (379 axSpA (136 women and 243 men) and 147 controls with chronic low back pain) were included. No major sex-specific differences in the diagnostic performance were shown for bone marrow oedema (DOR m: 3.0; f: 3.9). Fat metaplasia showed a better diagnostic performance in men (DOR 37.9) than in women (DOR 5.0). Lower specificity was seen in women for erosions (77% vs 87%), sclerosis (44% vs 66%), fat metaplasia (87% vs 96%).Conclusion The diagnostic performance of structural MRI markers is substantially lower in female patients with axSpA; active inflammatory lesions show comparable performance in both sexes, while still overall inferior to structural markers. This leads to a comparably higher risk of false positive findings in women