Detection rate of contrast-enhanced brain magnetic resonance imaging in patients with cognitive impairment

Abstract

Introduction: The number of brain MRI with contrast media performed in patients with cognitive impairment has increased without universal agreement. We aimed to evaluate the detection rate of contrast-enhanced brain MRI in patients with cognitive impairment.

Materials and methods: This single-institution, retrospective study included 4,838 patients who attended outpatient clinics for cognitive impairment evaluation and underwent brain MRI with or without contrast enhancement from December 2015 to February 2020. Patients who tested positive for cognitive impairment were followed-up to confirm whether the result was true-positive and provide follow-up management. Detection rate was defined as the proportion of patients with true-positive results and was compared between groups with and without contrast enhancement. Individual matching in a 1:2 ratio according to age, sex, and year of test was performed.

Results: The overall detection rates of brain MRI with and without contrast media were 4.7% (57/1,203; 95% CI: 3.6%-6.1%) and 1.8% (65/3,635; 95% CI: 1.4%-2.3%), respectively (P<0.001); individual matching demonstrated similar results (4.7% and 1.9%). Among 1,203 patients with contrast media, 3.6% was only detectable with the aid of contrast media. The proportion of patients who underwent follow-up imaging or treatment for the detected lesions were significantly higher in the group with contrast media (2.0% and 0.6%, P < .001).

Conclusions: Detection rate of brain MRI for lesions only detectable with contrast media in patients with cognitive impairment was not high enough and further study is needed to identify whom would truly benefit with contrast media.

Fig 1. Flow diagram of the study population.

Fig 2

(a, b, c) Images in a 66-year-old female patient with a small extra-axial mass at the right parietal convexity suggestive of meningioma (arrow), which became noticeable with the aid of contrast enhancement study. (a, T2 weighted image; b, FLAIR; c, contrast-enhanced T1 weighted image).

Fig 3. Images in a 75-year-old female patient with previous histories of right breast cancer and right renal cell carcinoma (clear cell type) with systemic metastases (retroperitoneum, lymph node, and lung).

Contrast-enhanced T1 weighted images showed multiple tiny nodular enhancing lesions suggestive of brain metastases (one of them on (c)), which were not detectable on axial T2 weighted images (a) and FLAIR images (b).

Fig 4. Images in an 86-year-old female patient presented with rapidly progressive dementia.

Infiltrative high signal intensity lesion was noted on axial T2 weighted image (a) and FLAIR (b) with mass effect and edema involving left basal ganglia. Homogeneous enhancing mass was noted at the left basal ganglia on axial contrast-enhanced T1 weighted images (c). Lymphoma was suggested with the aid of contrast enhancement study rather than high grade glioma.