Complete Symptom Resolution After Rest in Acute Dizziness: Implications for Selective Magnetic Resonance Imaging Use and Patient Out-of-Pocket Costs in Japan

Background/Objectives: We examined the association between symptom resolution after rest and causative central lesions on initial magnetic resonance imaging (MRI), and the patient-perspective economic implications of hypothetical MRI omission. Methods: This exploratory, single-center, retrospective observational study included 170 patients with dizziness who underwent MRI between April 2022 and March 2024. Symptoms were reassessed after 10 min of supine rest. Among patients discharged home, MRI-related charges were hypothetically omitted for those with complete resolution, with other care unchanged. Sensitivity analyses examined the impact of hypothetical additional outpatient revisit costs. Results: Causative central lesions were detected in 0 of 90 patients with complete resolution (0.0%; 95% confidence interval [CI], 0.0–4.0%) and 12 of 80 with residual symptoms (15.0%; 95% CI, 8.0–24.7%; p < 0.001). Among 89 discharged patients, hypothetical MRI omission in 54 (60.7%) reduced estimated initial medical expenditures by JPY 909,300 (22.6%); the median estimated patient-payment reduction was JPY 3552. In sensitivity analyses limited to additional outpatient revisits, estimated reductions remained positive across the principal scenarios but diminished as assumed revisit use increased. Conclusions: Complete symptom resolution was associated with a lower observed proportion of causative central lesions and warrants evaluation as information complementary to established assessment. Hypothetical selective MRI use reduced estimated initial expenditures and patient payments. These exploratory findings do not establish the safety of MRI omission; prospective validation incorporating clinical outcomes and downstream healthcare use is required.