Dual energy CT bests ultrasound for gout diagnosis; claims study

By Dr Satabdi SahaPublished On 2021-02-28T22:33:47+05:30 | Updated On 2021-03-01T11:02:05+05:30

Dual energy CT bests ultrasound for gout diagnosis; claims study

In a recent development, Feet/ankles or knees DECT alone has shown the best overall accuracy for gout diagnosis. Researchers further highlighted that the DECT–US combination or multiple joint imaging offered no additional increase in overall diagnostic accuracy.

The study findings have been put forth in Rheumatology.

Gout is characterized by an inflammatory response to the deposition of monosodium urate (MSU) crystals in the joints and soft tissue, which leads to acute or chronic arthropathy and gouty tophi formation. Diagnosis can be made on clinical and biochemical bases, and definite diagnosis requires microscopic demonstration of MSU crystals from the aspiration of the joint fluid, a method that is invasive and may have false negative results.

Keeping the dual energy ratio specific to uric acid crystals, the uric acid crystals are coloured green, whereas calcium is coloured blue. With DECT, it is also possible to quantify the overall tophus burden or volume of urate deposition without any user variability. Thus, makes DECT an ideal tool for evaluating any change in tophus burden and can be used for follow-up to document response to treatment.

Researchers undertook the recent study to examine the accuracy of dual-energy CT (DECT) vs ultrasound or their combination for the diagnosis of gout.

Using prospectively collected data from an outpatient rheumatology clinic at a tertiary-care hospital, the research team examined the diagnostic accuracy of either modality alone or their combination, by anatomical site (feet/ankles and/or knees), for the diagnosis of gout. They used two standards: (i) demonstration of monosodium urate crystals in synovial fluid (gold), and (ii) modified (excluding DECT and ultrasound) 2015 ACR–EULAR gout classification criteria (silver).

Data analysis revealed the following facts.

Of the 147 patients who provided data, 48 (33%) had synovial fluid analysis performed (38 were monosodium urate-crystal positive) and mean symptom duration was 9.2 years.
One hundred (68%) patients met the silver standard. Compared with the gold standard, diagnostic accuracy statistics for feet/ankles DECT, feet/ankles ultrasound, knees DECT and knees ultrasound were, respectively: sensitivity: 87%, 84%, 91% and 58%; specificity: 100%, 60%, 87% and 80%; positive predictive value: 100%, 89%, 97% and 92%; negative predictive value: 67%, 50%, 70% and 33%; area under the receiver operating characteristic curve: 0.93, 0.72, 0.89 and 0.66.
Combining feet/ankles DECT with ultrasound or knees DECT with ultrasound led to a numerically higher sensitivity compared with DECT alone, but overall accuracy was lower.
Similarly, combining imaging knees to feet/ankles also yielded a numerically higher sensitivity and negative predictive values compared with feet/ankles DECT alone, without differences in overall accuracy.
Findings were replicated compared with the silver standard, but with lower numbers.

For the full article follow the link: https://doi.org/10.1093/rheumatology/keaa923

Primary source: Rheumatology

rheumatology dual-energy ct gout diagnosis

Source : Rheumatology

Dr Satabdi Saha

Dr Satabdi Saha (BDS, MDS) is a practicing pediatric dentist with a keen interest in new medical researches and updates. She has completed her BDS from North Bengal Dental College ,Darjeeling. Then she went on to secure an ALL INDIA NEET PG rank and completed her MDS from the first dental college in the country – Dr R. Ahmed Dental College and Hospital. She is currently attached to The Marwari Relief Society Hospital as a consultant along with private practice of 2 years. She has published scientific papers in national and international journals. Her strong passion of sharing knowledge with the medical fraternity has motivated her to be a part of Medical Dialogues.