Dual-vitality computed tomography (DECT) appears to be to acquire restricted utility for differentiating between gout and calcium pyrophosphate deposition disease (CPPD), in step with a German prospective cohort search for. Findings had been reported at the annual European Congress of Rheumatology, held online this one year thanks to COVID-19.
Dr Valentin S. Schäfer
“Differentiation of gout and pseudogout, or CPPD, is incessantly refined,” stated presenting investigator Valentin S. Schäfer, MD, affiliate professor of inner remedy and head of the division of rheumatology and scientific immunology at University Correctly being facility Bonn (Germany).
“Arthrocentesis and subsequent polarization microscopy remains the gold well-liked,” he illustrious. “Novel diagnostic approaches, equivalent to DECT, have not too long previously been validated for gout, but restricted knowledge [are] available in the market on the use of DECT in patients with CPPD.”
The investigators studied 30 patients: 22 with suspected gout and 8 with suspected CPPD. All underwent arthrocentesis with subsequent polarization microscopy for definitive prognosis, plus scientific examination, ultrasound examination, archaic radiography, DECT, and evaluate of 12 laboratory parameters.
For prognosis of gout, DECT had a sensitivity and specificity of 59.1% and 100%, respectively, Dr. Schäfer reported, noting that this sensitivity falls considerably brief of the 90% beforehand reported for gout (Figure 1).
Figure 1: Gout tophus formation (bent arrow) confirmed on 80-kV DECT with colour-coded overlay displaying monosodium urate crystals in inexperienced and calcium in blue, as successfully as articular and juxta-articular osseous erosions (straight arrow).
Corresponding sensitivity and specificity had been 90.9% and 75% for ultrasound, 58.8% and 100% for archaic radiography, and 81.8% and 87.5% for the rheumatologists’ suspected scientific prognosis.
For prognosis of CPPD, DECT had sensitivity of 37.5% and specificity of 81.8%. Corresponding values had been 87.5% and 91% for ultrasound, 0% and 94.1% for archaic radiography, and 75.0% and 100% for suspected scientific prognosis (Figure 2).
Not one among the 12 laboratory parameters studied — uric acid, C-reactive protein, organic phosphate, and leukocytes, amongst others — vastly differentiated between conditions.
Figure 2: DECT image with colour-coded overlay shows standard findings of CPPD alongside the medial and lateral menisci (arrow) and calcium in tissues where or now not it’s now not in most cases realized (e.g., hyaline cartilage).
“Both ultrasound and suspected scientific prognosis had elevated sensitivities than DECT for gout and CPPD,” Dr. Schäfer concluded. “Extra studies with greater patient cohorts and presumably modified scan protocols are wanted in uncover to resolve the diagnostic utility of DECT in CPPD.”
Findings in Context
“Noninvasive, moral systems for distinguishing between gout and CPPD will toughen scientific care,” Sara Good ample. Tedeschi, MD, MPH, predicted in an interview.
“Arthrocentesis is painful in an acutely inflamed joint, would possibly well well be refined to form on tiny joints, and is underutilized in scientific prepare,” she elaborated. And ultrasound is operator dependent and would now not quantify crystal volume in and round the joint.
The quiz addressed by the quest for is therefore clinically linked, in step with Dr. Tedeschi, a rheumatologist at Brigham and Females’s Correctly being facility and assistant professor of remedy at Harvard Medical School, Boston.
On the different hand, amongst the patients with CPPD, the quest for did now not file particular phenotypes (acute inflammatory arthritis, continual inflammatory arthritis, and osteoarthritis with calcium pyrophosphate deposits), she illustrious. “It is a long way refined to diagram conclusions about the sensitivity or specificity of DECT for CPPD with out this files, severely amongst correct 8 CPPD patients.”
Moreover to, amongst the patients with gout, the proportion having new-onset disease with flare period decrease than 6 weeks and the proportion with tophi had been unknown, every of which affected DECT sensitivity in the previous search for that reported 90% sensitivity. “In step with the 95% self perception interval in the display search for, it’s a long way that you simply would possibly well well agree with that with a greater sample dimension, DECT sensitivity for gout would had been elevated,” she pointed out. “We additionally fabricate now not know the DECT tool settings, which impact DECT interpretation as determined or detrimental for the crystal of passion.”
Eventually, “it will maybe well well well be linked to know what joints had been aspirated and imaged in every community,” Dr. Tedeschi stated. “As an instance, if the well-known metatarsophalangeal (MTP) joint used to be aspirated and imaged for half of the gout patients but for now not one among the CPPD patients, that can well well additionally have an effect on the quest for interpretation.”
The quest for did now not bag any particular funding. Dr. Schäfer disclosed a ramification of commercial relationships with loads of pharmaceutical firms. Dr. Tedeschi disclosed receiving grant make stronger from the Nationwide Institutes of Correctly being to search round for imaging modalities for CPPD, and being first author on a search for evaluating the sensitivity of DECT, ultrasound, and x-ray for acute CPP crystal arthritis.
Ann Rheum Dis. 2020;79: 196. Summary
This text in the origin looked on MDedge.
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