Houston Methodist Study Pioneers Real-Time Imaging of Spinal Cord Bladder Control Function

A Houston Methodist Hospital-led research team has demonstrated for the first time that functional MRI can be used to capture real-time activity in the human spinal cord regions responsible for bladder control — a technical milestone that opens a new frontier in neurourology research and diagnosis.

A recent study on the breakthrough details the development and validation of a novel spinal cord functional MRI (fMRI) protocol, which the researchers showed can detect task-induced neural activity in the lumbosacral cord, the key spinal segments involved in lower urinary tract (LUT) control.

“Lower urinary tract control is a highly complex executive function that depends on continuous communication between the brain, spinal cord and bladder,” said Dr. Rose Khavari, the study's primary investigator and a Houston Methodist urologist and neurourology researcher. “Yet until now, nearly all of our real-time functional imaging has stopped at the brain. The spinal cord has been the missing link.”

The work, published in Neurourology and Urodynamics in 2025, overcomes longstanding barriers that have limited functional neuroimaging of the spinal cord, despite decades of progress in brain-based fMRI.

Solving a longstanding imaging challenge

While functional MRI is routinely used to study dynamic brain activity, applying the technique to the spinal cord has proven exceptionally difficult. The cord’s small size, constant motion from respiration and heartbeat, surrounding cerebrospinal fluid, and dense vascular structures generate noise that can obscure true neural signals.

In addition to those technical obstacles, researchers lacked a reliable, MRI-compatible task capable of selectively activating spinal circuits involved in bladder control without introducing motion artifacts.

Dr. Khavari’s team, including Dr. Betsy Salazar, Dr. Charles Mazeaud and Kris Hoffman, addressed both problems simultaneously.

The researchers developed a custom MRI-compatible device that delivers controlled, rhythmic suprapubic tapping to safely elicit a simulated bulbocavernosus reflex (sBCR), a well-established sacral spinal reflex critical to continence and voiding. The device standardizes force and timing across participants, eliminating variability associated with manual stimulation and preventing patient movement inside the scanner.

“This gave us a specific task that would reliably light up the spinal segments we know are involved in bladder control,” Dr. Khavari said.

Mapping spinal bladder circuitry in healthy humans

Using the new protocol, the team performed spinal cord fMRI on 20 healthy adult volunteers during natural bladder filling, assessing neural activity during both empty and full bladder states. Fifteen scans met strict quality criteria and were included in first-level analyses.

The imaging revealed task-induced activation across neuronal segments T10 through S5, encompassing sympathetic, parasympathetic and somatic nuclei previously implicated in bladder storage and voiding. Activation was detected during sBCR tasks in both bladder states, confirming that the protocol could capture functionally meaningful spinal cord activity in vivo.

Importantly, the study demonstrated feasibility rather than clinical diagnostic utility, Dr. Khavari emphasized.

“This was a pilot exploratory study,” she said. “The main point was to see if spinal cord fMRI for bladder control is possible — something many in the field believed could not be done.”

From lesion-based inference to real-time function

Historically, understanding of spinal cord control over the lower urinary tract has been derived largely from injury-based models — observations made after spinal cord trauma, tumors or neurological disease.

“This real-time functional data in humans without injury allows us to move beyond inference from lesions and toward direct observation of how these circuits actually work,” Dr. Khavari explained.

The implications are especially significant for patients with spinal cord injury, multiple sclerosis or intramedullary tumors, where bladder dysfunction severely impacts quality of life. Dr. Khavari said future studies will apply the same platform to patients with varying levels and severities of spinal cord injury to better characterize preserved and disrupted neural pathways.

A multidisciplinary foundation

The work required close collaboration among urologists, engineers, physicists, neurosurgeons and imaging scientists — a model Dr. Khavari says will be essential for future advances in spinal neuroimaging.

While further validation and larger studies are needed, the research establishes a foundational platform for integrating spinal cord function into the broader brain-bladder control model — and for eventually developing more precise diagnostic tools for neurogenic bladder disorders.

“We now know that this door is open,” Dr. Khavari said. “That’s exciting and it’s got a lot of people thinking and talking.”