Detection Of Monosodium Urate Crystals Research Articles

Virtual noncontrast images reveal gouty tophi in contrast-enhanced dual-energy CT: a phantom study

BackgroundDual-energy computed tomography (DECT) is useful for detecting gouty tophi. While iodinated contrast media (ICM) might enhance the detection of monosodium urate crystals (MSU), higher iodine concentrations hamper their detection. Calculating virtual noncontrast (VNC) images might improve the detection of enhancing tophi. The aim of this study was to evaluate MSU detection with VNC images from DECT acquisitions in phantoms, compared against the results with standard DECT reconstructions.MethodsA grid-like and a biophantom with 25 suspensions containing different concentrations of ICM (0 to 2%) and MSU (0 to 50%) were scanned with sequential single-source DECT using an ascending order of tube current time product at 80 kVp (16.5–220 mAs) and 135 kVp (2.75–19.25 mAs). VNC images were equivalently reconstructed at 80 and 135 kVp. Two-material decomposition analysis for MSU detection was applied for the VNC and conventional CT images. MSU detection and attenuation values were compared in both modalities.ResultsFor 0, 0.25, 0.5, 1, and 2% ICM, the average detection indices (DIs) for all MSU concentrations (35–50%) with VNC postprocessing were respectively 25.2, 36.6, 30.9, 38.9, and 45.8% for the grid phantom scans and 11.7, 9.4, 5.5, 24.0, and 25.0% for the porcine phantom scans. In the conventional CT image group, the average DIs were respectively 35.4, 54.3, 45.4, 1.0, and 0.0% for the grid phantom and 19.4, 17.9, 3.0, 0.0, and 0.0% for the porcine phantom scans.ConclusionsVNC effectively reduces the suppression of information caused by high concentrations of ICM, thereby improving the detection of MSU.Relevance statementContrast-enhanced DECT alone may suffice for diagnosing gout without a native acquisition.Key points• Highly concentrated contrast media hinders monosodium urate crystal detection in CT imaging• Virtual noncontrast imaging redetects monosodium urate crystals in high-iodinated contrast media concentrations.• Contrast-enhanced DECT alone may suffice for diagnosing gout without a native acquisition.Graphical

A glance into the future of gout.

Gout is characterized by monosodium urate (MSU) crystal deposits in and within joints. These deposits result from persistent hyperuricaemia and most typically lead to recurrent acute inflammatory episodes (gout flares). Even though some aspects of gout are well characterized, uncertainties remain; this upcoming decade should provide further insights into many of these uncertainties. Synovial fluid analysis allows for the identification of MSU crystals and unequivocal diagnosis. Non-invasive methods for diagnosis are being explored, such as Raman spectroscopy and imaging modalities. Both ultrasound and dual-energy computed tomography (DECT) allow the detection of MSU crystals; this not only provides a mean of diagnosis, but also has furthered gout knowledge defining the presence of a preclinical deposition in asymptomatic hyperuricaemia. Scientific consensus establishes the beginning of gout as the beginning of symptoms (usually the first flare), but the concept is currently under review. For effective long-term gout management, the main goal is to promote crystal dissolution treatment by reducing serum urate below 6 mg/dL (or 5 mg/dL if faster crystal dissolution is required). Current urate-lowering therapies’ (ULTs) options are limited, with allopurinol and febuxostat being widely available, and probenecid, benzbromarone, and pegloticase available in some regions. New xanthine oxidase inhibitors and, especially, uricosurics inhibiting urate transporter URAT1 are under development; it is probable that the new decade will see a welcomed increase in the gout therapeutic armamentarium. Cardiovascular and renal comorbidities are common in gout patients. Studies determining whether optimal treatment of gout will positively impact these comorbidities are currently lacking, but will hopefully be forthcoming. Overall, the single change that will most impact gout management is greater uptake of international rheumatology society recommendations. Innovative strategies, such as nurse-led interventions based on these recommendations have recently demonstrated treatment success for people with gout.

X-ray dark-field radiography for in situ gout diagnosis by means of an ex vivo animal study

Gout is the most common form of inflammatory arthritis, caused by the deposition of monosodium urate (MSU) crystals in peripheral joints and tissue. Detection of MSU crystals is essential for definitive diagnosis, however the gold standard is an invasive process which is rarely utilized. In fact, most patients are diagnosed or even misdiagnosed based on manifested clinical signs, as indicated by the unchanged premature mortality among gout patients over the past decade, although effective treatment is now available. An alternative, non-invasive approach for the detection of MSU crystals is X-ray dark-field radiography. In our work, we demonstrate that dark-field X-ray radiography can detect naturally developed gout in animals with high diagnostic sensitivity and specificity based on the in situ measurement of MSU crystals. With the results of this study as a potential basis for further research, we believe that X-ray dark-field radiography has the potential to substantially improve gout diagnostics.

The diagnostic performance of dual energy CT for diagnosing gout: a systematic literature review and meta-analysis.

This study aimed to assess the utility of dual energy CT (DECT) for diagnosing gout. A systematic literature search was performed in PubMed, EMBASE and Cochrane Library. Studies evaluating the utility of DECT for diagnosing gout were included. Reference standards were detection of monosodium urate crystals at SF assessment or a validated set of criteria. The methodological quality of studies was evaluated according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 criteria. Data from person-based and joint-/localization-based evaluations were pooled separately, and subgroup analyses for disease stage/duration and reference standard were performed. Ten studies were included; in person-based evaluations, the pooled (95% CI) sensitivity and specificity were 0.81 (0.77, 0.86) and 0.91 (0.85, 0.95), respectively. In joint-based evaluations, they were 0.83 (0.79, 0.86) and 0.88 (0.83, 0.92), respectively. At short disease duration (⩽6 weeks), the pooled (95% CI) sensitivity and specificity at the joint level were 0.55 (0.46, 0.64) and 0.89 (0.84, 0.94), respectively. DECT has a high diagnostic accuracy in established gout, but its diagnostic sensitivity is low in subjects with recent onset gout.

Detection of monosodium urate crystals with dual-energy CT in gout patients

Objective To evaluate the application of the dual-energy CT (DECT) in detection of monosodium urate (MSU) crystals in gout patients. Methods The imaging and clinical data of 101 patients with suspected gout were retrospectively analyzed, including 64 cases of clinically diagnosed gout (gout group) and 37 non-gout cases (non-gout group). The DECT examination was performed for 85 joints in gout group and 42 joints in non-joint group. The value of DECT in detection of MSU crystals was evaluated with receiver operating characteristic (ROC) curve. Results There were significant differences in gender (χ2=5.32, P=0.03) and blood uric acid levels (t=1.95, P=0.04) between gout and non-gout groups. The detection rate of MSU in gout group was significantly higher than that of non-gout group (χ2=30.52, P<0.001). The area under the ROC curve (AUC) of DECT in detection of was 0.74±0.05 (Mean±SE), 95%CI: 0.64-0.85. The sensitivity, specificity, positive predictive value and negative predictive value of the DECT in detection of gouty stone was 0.844, 0.703, 83.1% and 72.2%, respectively. Conclusion The dual-energy CT has high sensitivity, specificity and reliability for the detection and diagnosis of monosodium urate crystals in joints of gout patients. Key words: Radiography, dual-energy scanned projection; Gout; Arthritis, gouty; Crystallization, uric acid

Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis.

Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings.

Cytospin preparations are superior to common smears in the detection of monosodium urate crystals in low-cellular synovial fluids.

In cases of gout with a low synovial fluid (SF) leukocyte count and atypical clinical presentation, such as in intercritical periods, the load of monosodium urate (MSU) crystals is frequently low, and thus, methods to improve the crystal detection may be beneficial. We compared the MSU crystal detection rates between cytospin slides and common smear preparations in low-cellular (<2,000/μl) SF samples of patients with gout. We determined the number of MSU crystals/15 high power fields (HPF) at × 1,000 magnification by polarised microscopy in cytospin preparations and smears in SF samples of 17 patients with MSU-crystal-proven gout and compared the two methods statistically. All of the cytospin slides (100 %) contained MSU crystals and showed a median number of 124 crystals/15 HPF (range 2-3,915), whereas 5 of the 17 smears (29 %) were MSU-crystal-negative, with a median count of 2 crystals/15 HPF (range 0-430/HPF). The difference was statistically highly significant (p < 0.0001). In conclusion, we have shown that the cytospin technique is superior to smears in the detection of MSU crystals in SF with a low SF leukocyte count. In light of our observations, we recommend the use of cytocentrifuges for routine crystal analysis in such cases.

Imaging in gout

Imaging has the potential to assess various pathological manifestations of gout, including monosodium urate (MSU) crystal deposition, tophus formation and cartilage, soft tissue, and bone pathology. This review discusses recent research examining the role of imaging to assess the manifestations of disease. Various imaging techniques are used in the assessment of gout, including plain radiography, ultrasonography, conventional computed tomography (CT), dual energy computed tomography (DECT), and MRI. Potential roles for ultrasonography are MSU crystal detection, measurement of tophi, and assessment of disease complications. Ultrasonography may allow detection of MSU crystals in patients with hyperuricaemia, prior to development of clinically apparent gout. Conventional CT allows excellent visualization of tophi and bone erosion. DECT is a promising method of noninvasive MSU crystal detection. MRI allows assessment of tophi, synovial and soft tissue disease, and bone pathology. The relative absence of MRI bone marrow oedema in gout suggests that the mechanisms of bone erosion in gout are quite different from those in other erosive arthropathies. Imaging modalities have provided important insights into the pathology of gout. The role of various imaging techniques in gout diagnosis, monitoring, and prediction of outcome is rapidly developing.

Management Of Acute Gout: A Review Article

Gout is the most common cause of inflammatory arthritis in men aged over 40 years and is frequently encountered in clinical practice. Gout is currently the most common form of inflammatory arthritis in men. The overall incidence of gout has increased rapidly in the past 20 years. Some of the risk factors for the development of gout include: increased ethanol intake, high dietary purine consumption, obesity and the use of certain drugs, such as diuretics. Another important risk factor for the development of gout is hyperuricaemia. Acute gout can be diagnosed on the basis of detection of monosodium urate crystals in the synovial fluid of affected joint. The management of acute gouty arthritis includes use of colchicine and other anti-inflammatory drugs. Now a days NSAIDs are commonly prescribed in acute gouty arthritis because colchicine exert side effects.