Impact of Size Thresholds on the Diagnosis of Incidental Adrenal Lesions: A Systematic Review and Meta-Analysis.

BACKGROUND: Preferred size-threshold recommendations for management of incidental adrenal lesions remain controversial. PURPOSE: This meta-analysis aimed to compare the diagnostic accuracy of different size thresholds for detecting malignancy in patients with incidental adrenal lesions on imaging. MATERIALS AND METHODS: A systematic review of MEDLINE, Embase, Scopus, the Cochrane Library, and the gray literature, covering the period from inception to September 2021, was performed. Studies with >10 patients evaluating the diagnostic accuracy of imaging size thresholds for detecting malignancy in patients with incidental adrenal lesions and no prior history of cancer were included. Study, clinical, imaging, and accuracy data for eligible studies were independently acquired by two reviewers. Primary meta-analysis was performed using a bivariate mixed-effects regression model. Risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. RESULTS: From 2,690 citations, 40 studies (9,794 patients with mean age ranging from 41 to 66 years) were included. Most (36 of 40) were retrospective single-center studies. CT with or without MRI served as the index test(s). Sensitivity and specificity values, respectively, by size threshold used in the included studies were as follows: 85% (95% confidence interval [CI] 74%-91%) and 39% (95% CI 23%-57%) for 3-cm thresholds; 85% (95% CI 78%-90%) and 75% (95% CI 62%-85%) for 4-cm thresholds; 70% (95% CI 56%-81%) and 74% (95% CI 59%-85%) for 5-cm thresholds; and 75% (95% CI 67%-82%) and 77% (95% CI 62%-87%) for 6-cm thresholds. No cause for variability in sensitivity or specificity was identified on subgroup analysis of the 4-cm threshold. Nearly half of the studies (19 of 40) had at least one QUADAS-2 domain with a high risk of bias. CONCLUSIONS: A 4-cm size threshold demonstrates the highest combined sensitivity and specificity, with a preserved specificity compared with higher size thresholds, but with a trend toward improved sensitivity. Future research reevaluating 4-5 cm size thresholds while excluding characteristically benign lesions by imaging may help redefine a size threshold that has improved specificity but preserved sensitivity, compared with the existing 4-cm threshold.

Parallel Line Sign-A New MRI Sign Associated With Chronic Sacroiliitis: Prevalence, Characteristics, and Associations.

Purpose: The purpose is to demonstrate the existence of the parallel line sign (PLS), a dark line parallel to the sacroiliac joint (SIJ), and determine its prevalence, characteristics, and associations. Methods: 200 consecutive SIJ MRIs referred by rheumatologists were retrospectively reviewed for the presence of the PLS. Presence and extent of imaging features of sacroiliitis (bone marrow edema, fatty infiltration, erosions, sclerosis, and ankylosis) were evaluated. Results: Prevalence of PLS was 11.5% (23/200), with 9 subjects having bilateral PLS, resulting in 32 SIJs showing a PLS. Every PLS involved the synovial portion of the SIJ, and almost all (31/32, 96.9%) involved the iliac (rather than sacral) side of the SIJ. Every PLS occurred with at least one established imaging feature of sacroiliitis. Presence of a PLS was associated with higher prevalence of erosions (78.3% vs 36.7% in those without PLS, P < .001), greater extent of SIJ involvement by erosions (3.6 ± 1.3 vs 2.3 ± 1.1 quadrants of the SIJ involved, P < .001), and higher density of erosions per centimeter (88.9% vs 46.2% with >2 erosions/cm, P = .001). There was higher prevalence of bone marrow edema, fatty infiltration, and sclerosis in those with PLS compared to those without PLS (P = .001, P < .001, and P = .006, respectively). Extent of involvement by any of these features was not significantly different between the two groups (P = .22, P = .16, and P = .46, respectively). Conclusions: The PLS is associated with imaging features of chronic sacroiliitis, especially erosions. Knowledge of the existence of the PLS may help avoid misdiagnosis of an insufficiency fracture and increase confidence in the diagnosis of sacroiliitis.

Maigne Syndrome - A potentially treatable yet underdiagnosed cause of low back pain: A review.

BACKGROUND: First discussed by Dr. Robert Maigne in the late 1980s, Maigne Syndrome is an often unrecognized and treatable cause of low back pain. It can be separated into two distinct entities. The central variant is a result of nerve afferent input secondary to changes of facet joint arthropathy at the thoracolumbar junction. The peripheral variant is a result of impingement of the medial branch of the superior cluneal nerve, which arises from the posterior rami of the lower thoracic and upper lumbar nerve roots, and results in similar clinical symptoms and signs. OBJECTIVE: To review the current literature for a comprehensive description of Maigne Syndrome, its diagnosis and management. METHODS: Evidence was gathered using two main medical databases, namely PubMed and Google Scholar. Search terms included 'Maigne's Syndrome', 'Maigne facet', 'thoracolumbar junction syndrome', 'cluneal nerve entrapment', 'posterior iliac crest trigger point', 'pseudosciatica', as well as various permutations of these terms. RESULTS: The initial search generated 52 articles. These were screened, and duplicate and irrelevant articles were removed. Using the remaining articles, and with evaluation of their cited references, we selected 28 articles for review. Most of these consisted of case reports, many of which were published in rehabilitation, chiropractic and medical journals. The papers explored topics such as anatomy, cluneal nerve imaging, and treatment of nerve entrapment and facet related back pain syndromes, and have been included in this review, which is, to the best our knowledge, the most comprehensive description of Maigne Syndrome to date. CONCLUSION: The keys to the diagnosis of Maigne Syndrome include an awareness of the mechanical causes of back dominant pain, an understanding of the relevant anatomy, a specific clinical examination, and focused radiological guided anesthetic blocks. Treatment is available, and as in all back-pain etiologies, is most effective in the early stages of the disease.