Imaging Pearls ❯ Musculoskeletal ❯ Gout
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- Genetic Vascular Diseases
- Marfan Syndrome
- Ehlers Danlos Syndrome
- Loeys Dietz Syndrome - Genetic Vascular Diseases
- What is the genetic defect in each syndrome?
- What are the classic as well as unique vascular imaging findings in each of the syndromes?
- What are the extra-vascular findings that may help with reaching a correct diagnosis?
- What are the unique clinical issues in each syndrome and how are they managed? - "Spinal and foot abnormalities were the most clinically important skeletal findings. Eleven patients had talipes equinovarus, and nineteen patients had cervical anomalies and instability. Thirty patients had scoliosis (mean Cobb angle [and standard deviation], 30 degrees +/- 18 degrees ). Two patients had spondylolisthesis, and twenty-two of thirty-three who had computed tomography scans had dural ectasia. Thirty-five patients had pectus excavatum, and eight had pectus carinatum. Combined thumb and wrist signs were present in approximately one-fourth of the patients. Acetabular protrusion was present in approximately one-third of the patients and was usually mild."
Musculoskeletal findings of Loeys-Dietz Syndrome
Erkula G et al.
J Bone Joint Surg Am 2010 Aug 4; 92(9);1876-1883 - "Loeys-Dietz syndrome is a recently recognized multisystemic disorder caused by mutations in the genes encoding the transforming growth factor-beta receptor. It is characterized by aggressive aneurysm formation and vascular tortuosity. We report the musculoskeletal demographic, clinical, and imaging findings of this syndrome to aid in its diagnosis and treatment.“
Musculoskeletal findings of Loeys-Dietz Syndrome
Erkula G et al.
J Bone Joint Surg Am 2010 Aug 4; 92(9);1876-1883 - Certain tumors in the pediatric age group are not only more frequent but have signatures that may allow a very specific diagnosis. These include but are not limited to the following tumors;
- - aneurysmal bone cysts (expansile lesion with thin septations and fluid-fluid levels)
- unicameral bone cysts (expansile lesion with thin rim and serous fluid which is homogeneous on CT)
- osteoid osteoma (key finding is lesion nidus with subtle periosteal reaction)
- chondroblastoma (key is lytic lesion in epiphyseal location) - - osteochondroma (these are exostotic with smooth margins)
- osteosarcoma (mixed lytic and sclerotic lesion with osteoid matrix present)
- chondrosarcoma (uncommon except in malignant degeneration of an exostosis, chondroid matrix)
- myositis ossificans (soft tissue calcification along rim of lesion usually a result of prior trauma. Can simulate tumor mass on CT and may be hot on PET.)
- “ A diagnosis of gout is generally straightforward and is usually reached by evaluating clinical, laboratory, and radiologic findings. By using specific attenuation characteristics to differentiate urate crystals from calcium, dual energy CT may be helpful when the diagnosis is unclear, as in cases of atypical clinical manifestations, discordant levels of serum urate, or in differentiating an acute attack from chronic changes.”
Clinical Utility of Dual-Energy CT for Evaluation of Tophaceous Gout
Desai MA et al.
RadioGraphics 2011;31:1365-1375 - “ Dual-energy CT may be used to differentiate uric acid from calcium in musculoskeletal tissue, allowing gouty urate crystals to be distinguished from bone or dystrophic calcifications.”
Clinical Utility of Dual-Energy CT for Evaluation of Tophaceous Gout
Desai MA et al.
RadioGraphics 2011;31:1365-1375 - “ In the most common clinical manifestations of acute gout, rapid onset of a painful monoarthopathy occurs in the distal appendicular skeleton, often in the first metatarsophalangeal joint, in a middle aged man or postmenopausal woman. Atypical clinical manifestations also are seen with increased frequency in certain segments of the population, including the elderly and patients who underwent organ transplantation and those with a tumor, prostheses and genetic mutations.”
Clinical Utility of Dual-Energy CT for Evaluation of Tophaceous Gout
Desai MA et al.
RadioGraphics 2011;31:1365-1375 - “ Unlike other modalities, dual energy CT is inherently able to distinguish urate crystal deposits from surrounding structures, and it provides sensitive and specific volumetric quantification with no user variability.”
Clinical Utility of Dual-Energy CT for Evaluation of Tophaceous Gout
Desai MA et al.
RadioGraphics 2011;31:1365-1375 - Mimics of Gout: Differential Diagnosis
- Septic arthritis
- Osteomyelitis
- Pseudogout (calcium pyrophosphate deposition disease)
- Rheumatoid arthritis
- Malignancy (lytic lesion)
- Tendinopathy - Role of Dual Energy CT in the Diagnosis of Gout as a Problem Solver
- Unusual clinical presentations
- Discordant uric acid levels
- Acute vs chronic gout
- Subclinical disease
- Mimics of gout vs gout
- Quantification of gout for therapy monitoring - DE Protocol
Single acquisition at both 80 and 140 kVp
Color coded mapping with Green being positive for urate crystals
3D mapping useful for defining extent of disease