The advanced imaging of gouty tophi

Abstract

Gout is a metabolic disorder in which there is hyperuricemia caused by an increase in production or a decrease in excretion of uric acid. Long-lasting hyperuricemia causes the deposition of monosodium urate crystals in the joints and soft tissues, triggering gouty arthritis and, if not properly treated, the formation of gouty tophi. The diagnosis of gout is usually based on clinical presentation and laboratory examinations, long before any abnormality can be demonstrated with imaging. Radiography is the primary imaging modality used in the initial evaluation of gouty arthritis. Ultrasonography, CT, MRI, and nuclear medicine are seldom necessary. Occasionally a tophus has an unusual presentation and simulates neoplasm or infection prompting the utilization of cross-sectional imaging for further evaluation and surgical planning. Cross-sectional imaging is also used in areas that are difficult to visualize on radiographs such as spine, sacroiliac joints, and soft tissues.

Severe back pain and lower extremities weakness in a young male

“…The MRI helped confirm the diagnosis. The low signal intensity of the epidural mass across T 1 weighted images (T1WI), T 2 weighted images (T2WI) and shorttau inversion-recovery (STIR) sequences is as expected with non-signal-producing crystals [2].…”

“…A right posterolateral epidural mass originating from the affected T10-11 facet joint resulted in spinal canal stenosis (Figures 1 and 2). The mass showed characteristic tophi density, with mean attenuation of 150-160 HU, which is more than soft tissue but less than calcifications [2]. The MRI helped confirm the diagnosis.…”

“…Tophi can involve the epidural space, intradural-extramedullary compartment, ligamentum flavum, pedicles, facet joint capsule or neural foramen. The most common sites among these are the facet joints and ligamentum flavum [2]. In addition to cord compression, other clinical manifestations of spinal gout include back pain, lumbar radiculopathy, spondylolisthesis, paraplegia and cauda equina syndrome [2].…”

“…The typical imaging findings of spinal metastasis include low signal intensity on T1WI with corresponding high signal intensity on T2WI and STIR, which were absent in this case and made this diagnosis less likely. However, signal intensity on T2WI may be heterogeneous because of urate crystals or calcium deposition, making the distinction from neoplasm difficult in a patient with gout [2]. Along with the imaging results, neoplasm is also less likely because of the patient's young age and lack of primary malignancy.…”

Uric acid enhances T cell immune responses to hepatitis B surface antigen-pulsed-dendritic cells in mice

“…In hyperuricemia, it is well-known that uric acid can precipitate in the joints, where they cause gout, and/or in other tissues causing inflammation [26] . Therefore, the dose of uric acid administration is of crucial importance.…”