Reporting subtle details imperative for patients with suspected dementia

As diagnosis and treatment of dementia improves, detailed characterization of even the most subtle findings on brain imaging for symptomatic patients becomes important in radiology reports. The use of standardized visual rating scales may enhance the reporting of MRI exams for dementia and eliminate the risk of not of not omitting diagnostic information regarding frontotemporal dementias.

Frontotemporal dementias (FTDs), a complex group of disorders typified by selective degeneration of the frontal and temporal lobes of the brain, account for 10%-20% of cases of early-onset dementia. There are several subtypes of FTDs, with differing characteristics, stages of progression, and potential treatments. Recent and continuing improvements in the understanding of these subtypes and their prognostic implications, as well as the likely future development of targeted therapies for specific syndromes of dementia have made it critically important that radiologists be able to detect subtle imaging features of the subtypes of dementia in brain MRI images.

But is this happening? A multi-institutional team of British researchers conducted a retrospective neurological and radiological review of the medical records of 22 patients with a definitive diagnosis of FTD who had been treated at a cognitive disorders clinic in Exeter over the study’s seven year time frame. Brain MRI exams were performed at either the Royal Devon and Exeter Hospital in Exeter or the Derriford Hospital in Plymouth.

For the study, published in the January issue of Clinical Radiology, the patients’ brain MRI images were graded using a visual rating scale by a neuroradiologist and a consultant neurologist. The clinical team paid particular attention to the appearance of the frontal and temporal lobes. Findings of radiology reports were ranked by detail and accuracy of the actual report and clinical interpretation.

Principal investigator Adam Zeman, M.D., professor of cognitive and behavioural neurology of the Cognitive Neurology Research Group at the University of Exeter Medical School, and colleagues reported that only six of the 22 reports — 27% — provided both a comprehensive and accurate description of the radiological findings. Only two additional reports provided a full and accurate interpretation. The authors reported that the most common errors included failure to identify focal atrophy, misinterpretation of atrophy due to dementia in terms of previous stroke, head injury or encephalomalacia, and failure to suggest the diagnosis of FTD when relevant radiological changes were visible on the images.

Their article describes in detail the symptoms and radiological characteristics of subtypes of frontotemporal dementia, including behavioral-variantFTD, semantic dementia, agrammatic and logopaenic primary progressive aphasia, corticobasal syndrome, and progressive supranuclear palsy. It also includes examples of the typical brain imaging appearances of these conditions..

The authors recommend that routine use of standardized visual rating scales, specifically the medial temporal atrophy scale and the global cortical atrophy scale, would help non-specialist reporting radiologists increase their detection of subtle patterns of differential atrophy in the frontal and temporal lobes. “Routine use of such scales when reporting dementia imaging will improve the sensitivity of descriptive reports, and in conjunction with multidisciplinary meetings, lead to more accurate interpretations,” they wrote.

The research team intends to pilot the use of the visual rating scales and subsequently reevaluate the quality of radiology reporting of brain MRI exams of patients presenting with symptoms of dementia.

REFERENCE

1. Dewer B., Rogers P, Ricketts J., et al. The radiological diagnosis of frontotemporal dementia in everyday practice: an audit of reports, review of diagnostic criteria, and proposal for service improvement. 2016 Clin Radiol. 71;1: 40-47.