Diagnosing polymyalgia rheumatica on <Superscript>18</Superscript>F-FDG PET/CT: typical uptake patterns

Objective

The diagnosis of polymyalgia rheumatica (PMR) is often challenging, since similar clinical features and laboratory findings can be observed in several inflammatory conditions. PMR involves affected sites in a specific manner, and ¹⁸F-FDG PET/CT has the advantage for assessing the disease activity of each site. The purpose of this study was to identify the patterns of ¹⁸F-FDG uptake that suggest the diagnosis of PMR.

Methods

We studied 60 patients who had undergone ¹⁸F-FDG PET/CT scans for workup of suspected PMR, arthritis, enthesitis, or myopathy. Final diagnoses were made by board-certified rheumatologists. The incidence of significant ¹⁸F-FDG uptake, higher than mediastinal blood pool, of the following sites were compared among PMR patients and patients with other diseases: wrists, elbows, shoulders, sternoclavicular joints, acromioclavicular joints, spinous processes, ischial tuberosities, and greater trochanters. For the spinous processes, the incidence of “Y”-shaped uptake along the interspinous bursae was also evaluated.

Results

A definitive diagnosis of PMR was given to 16 of 60 patients. The incidence of significant ¹⁸F-FDG uptake in the definitive PMR group was 6% for wrists and for elbows, 88% for glenohumeral and sternoclavicular joints, 25% for acromioclavicular joints, 81% for spinous processes, 69% for ischial tuberosities, and 81% for greater trochanters. Patients with PMR showed a significantly higher incidence of “Y”-shaped uptake along the interspinous bursae than the other patients (38 vs. 9%) (P?=?0.016).

Conclusion

¹⁸F-FDG uptake distribution patterns and morphology can contribute to the diagnosis of PMR. Significant ¹⁸F-FDG uptake in the sternoclavicular joints is one of the characteristic findings in patients with PMR as well as the uptake in the shoulders, ischial tuberosities, and greater trochanters. “Y”-shaped spinous process uptake may be one of the specific findings for PMR.

     

Increased non-HDL-C level linked with a rapid rate of renal function decline in HIV-infected patients

Background

The risk of developing CKD is increased in HIV-infected patients; however, the relationship between renal function decline and lipid abnormalities currently remains unclear in these patients.

Methods

A retrospective cohort study was conducted on 661 HIV-infected patients, whose estimated glomerular filtration rates (eGFRs) were consecutively measured over 6 years. The rate of declines in eGFR per year was calculated, with decreases being evaluated using a linear mixed effect model. The distribution of decreases in eGFR ≥ 30 % from baseline during the follow-up period was compared across quartiles of non-high-density lipoprotein cholesterol (HDL-C) levels using the Cochran–Armitage test. A multivariate logistic regression model was built to examine the relationship between dyslipidemia and decreases in eGFR.

Results

The prevalence of CKD increased from 8.5 to 21.2 % during the follow-up. The average of 6 annual eGFR decline rates was 2.01 ± 0.09 ml/min/1.73 m²/year, which was more than 6-fold higher than that of age-matched controls. The distribution of decreases in eGFR significantly increased across the quartiles of non-HDL-C (p value for trend = 0.0359). Non-HDL-C levels greater than the median value of the cohort were identified as a significant risk factor for decreased eGFR [odds ratio (95 % confidence interval), 1.77 (1.07–3.00)].

Conclusion

Increased non-HDL-C levels are a risk factor for renal function decline in HIV-infected patients.

     

Use of Vesicular Stomatitis Virus Pseudotypes Bearing Hantaan or Seoul Virus Envelope Proteins in a Rapid and Safe Neutralization Test

A vesicular stomatitis virus (VSV) pseudotype bearing hantavirus envelope glycoproteins was produced and used in a neutralization test as a substitute for native hantavirus. The recombinant VSV, in which the enveloped protein gene (G) was replaced by the green fluorescent protein gene and complemented with G protein expressed in trans (VSVΔG*G), was kindly provided by M. A. Whitt. 293T cells were transfected with plasmids for the expression of envelope glycoproteins (G1 and G2) of HTNV or SEOV and were then infected with VSVΔG*G. Pseudotype VSV with the Hantaan (VSVΔG*-HTN) or Seoul (VSVΔG*-SEO) envelope glycoproteins were harvested from the culture supernatant. The number of infectious units (IU) of the pseudotype VSVs ranged from 10⁵ to 10⁶/ml. The infectivity of VSVΔG*-HTN and VSVΔG*-SEO was neutralized with monoclonal antibodies, immune rabbit sera, and sera from patients with hemorrhagic fever with renal syndrome, and the neutralizing titers were similar to those obtained with native hantaviruses. These results show that VSVΔG*-HTN and -SEO can be used as a rapid, specific, and safe neutralization test for detecting hantavirus-neutralizing antibodies as an effective substitute for the use of native hantaviruses. Furthermore, the IU of VSVΔG*-HTN and -SEO did not decrease by more than 10-fold when stored at 4°C for up to 30 days. The stability of the pseudotype viruses allows distribution of the material to remote areas by using conventional cooling boxes for use as a diagnostic reagent.     

Mediating Factors Between Parental Socioeconomic Status and Small for Gestational Age in Infants: Results from the Hokkaido Study on Environment and Children’s Health

Maternal and Child Health Journal - Previous studies indicated a significant association between small for gestational age (SGA) in infants and their parents' socioeconomic status (SES). Thus,...     

Antigenic Properties of N Protein of Hantavirus

Hantavirus causes two important rodent-borne viral zoonoses, hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus pulmonary syndrome (HPS) in North and South America. Twenty-four species that represent sero- and genotypes have been registered within the genus Hantavirus by the International Committee on Taxonomy of Viruses (ICTV). Among the viral proteins, nucleocapsid (N) protein possesses an immunodominant antigen. The antigenicitiy of N protein is conserved compared with that of envelope glycoproteins. Therefore, N protein has been used for serological diagnoses and seroepidemiological studies. An understanding of the antigenic properties of N protein is important for the interpretation of results from serological tests using N antigen. N protein consists of about 430 amino acids and possesses various epitopes. The N-terminal quarter of N protein bears linear and immunodominant epitopes. However, a serotype-specific and multimerization-dependent antigenic site was found in the C-terminal half of N protein. In this paper, the structure, function, and antigenicity of N protein are reviewed.