Full Breakdown
fMRI-Guided Targeting Boosts Accelerated TMS Efficacy in Treatment-Resistant Depression
6/25/2026, 4:04:41 AM
Accelerated TMS Trial Shows Imaging-Driven Gains
Investigators at the Center for Brain Circuit Therapeutics, Mass General Brigham and Harvard Medical School conducted a randomized clinical trial from July 2023 to March 2025. Forty adults (22 female, mean age 45.7) with major depressive disorder and moderate-to-severe treatment resistance received accelerated transcranial magnetic stimulation (aTMS) over one week. Participants were randomly assigned to aTMS targeting based on individual resting-state functional MRI (connectivity-based) or conventional scalp-based Beam F3 measurements.
Background: TMS and Functional Imaging in Depression
Since FDA clearance in 2008, TMS has been a non-invasive option for depression unresponsive to medication. Conventional targeting relies on scalp landmarks that ignore personal variations in neural circuitry. Functional connectivity neuroimaging maps synchrony between brain regions at rest, offering a potential route to personalize stimulation sites. Prior retrospective analyses suggested benefit, but prospective evidence remained limited.
Study Design, Participants, and Targeting Methods
All participants completed a 41-minute multiecho resting-state fMRI scan. The connectivity-based target was defined as the left dorsolateral prefrontal cortex region most correlated with a published convergent depression circuit, which includes negative connectivity to the subgenual cingulate cortex. The scalp-based target used the Beam F3 method. Both groups received high-dose aTMS (multiple sessions per day) while participants, TMS technicians, and raters remained blinded to assignment.
Clinical Outcomes and Quantitative Findings
One month post-treatment, the connectivity-based group showed a median MADRS reduction of 24 points (IQR 19-28) versus 18 points (IQR 10-23) in the scalp-based group (p = .02). Response rates were 80 % compared with 60 %. The effect size was 0.8 (Cohen d analog; 95 % CI 0.26-1.54) with a number needed to scan of five individuals. Target reproducibility within participants averaged 4.47 mm, while inter-individual differences averaged 12.97 mm (p < .001).
Official Statements from Study Leaders
Corresponding author Joseph J. Taylor, MD, PhD, emphasized that the trial quantifies the added clinical value of imaging-guided aTMS beyond practical convenience. He noted that demonstrating a measurable advantage is essential because functional imaging increases procedural cost and complexity. The authors also highlighted the need for larger, multisite trials to confirm scalability and long-term efficacy.
Criticism, Limitations, and Unaddressed Gaps
The investigators acknowledge a relatively small sample size and single-site design, which limit generalizability. Cost considerations for routine fMRI acquisition remain a barrier to widespread adoption. Additionally, the study did not assess durability of response beyond one month, leaving long-term outcomes uncertain.
Verbatim Quotes
- “Neuroimaging has taught us a tremendous amount about the brain, but it has been difficult to show that imaging can directly improve patient care,” — Joseph J. Taylor, MD, PhD
- “It is important to address this knowledge gap because imaging adds cost and complexity to TMS treatment.” — Joseph J. Taylor, MD, PhD
- “Retrospective analyses have hinted that functional imaging could be used to improve outcomes, but prospective evidence has been limited,” — Joseph J. Taylor, MD, PhD
- “Our recent clinical trials provide prospective evidence that there may be clinical advantages to using functional imaging to guide aTMS treatment.” — Joseph J. Taylor, MD, PhD
Next Steps: Larger Validation Efforts
The research team plans a multicenter trial with a broader patient population to verify efficacy, assess durability of antidepressant effects, and perform cost-effectiveness analyses. Successful replication could inform guidelines for integrating functional neuroimaging into routine aTMS protocols for treatment-resistant depression.
