A Study to Evaluate Evacuation Mechanisms Using Advanced Brain Imaging


About this study

The objective of this study is to compare the central neural circuitry with fMRI (7T) in 30 asymptomatic healthy controls, 30 constipated patients without DD, and 30 constipated patients with DD at rest (functional connectivity analysis), during rectal distention to desire to defecate and urgency, and during evacuation. 




Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria - Controls:

  • Healthy volunteers aged 18-80 years old
  • Able to provide written informed consent before participating in the study.
  • Able to communicate adequately with the investigator and to comply with the requirements for the entire study.

Inclusion Criteria - Constipated Patients:

  • Male and female volunteers aged 18-80 years.
  • Individuals with chronic constipation for 1 year, with 2 or more of the following symptoms for 3 months or longer: < 3 bowel motions/week, straining ≥ 25% of time, hard or lumpy stools ≥ 25% of time, anal digitation ≥ 25% of time, incomplete evacuation ≥ 25% of time, feeling of anorectal blockage ≥ 25% of time.
  • Able to provide written informed consent before participating in the study.
  • Able to communicate adequately with the investigator and to comply with the requirements for the entire study.

Exclusion Criteria - Controls:

Items marked with an asterisk also apply to patients

  • Clinical evidence of significant cardiovascular, respiratory, renal, hepatic, gastrointestinal, hematological, neurological, psychiatric or other disease that may interfere with the objectives of the study and/or pose safety concerns.*
  • Current symptoms of a functional gastrointestinal disorder assessed by questionnaire.
  • Putative risk factors for pelvic floor trauma; i.e., six or more vaginal deliveries, birthweight > 4500gms (macrosomia), or known 3rd or 4th degree perineal tear.
  • Medications that are likely to alter gastrointestinal motility: e.g., opiates and  anticholinergic medications; a stable dose of thyroxine and low doses of tricyclic agents (e.g., up to amitriptyline (50 mg daily).
  • Active rectal inflammation, cancer; perianal sepsis; history of pelvic radiation in the past 3 years, rectal resection, or inflammatory bowel disease.*
  • Anxiety or depression as assessed by the Hospital Anxiety and Depression Questionnaire.
  • Pregnant women, prisoners and institutionalized individuals.*
  • Patients with safety contraindications to routine clinical 7T MRI as determined by the Mayo Clinic Rochester MR Safety Committee.*
  • Claustrophobic patients that cannot undergo MRI without anxiolytic medication.*
  • Patients with known vestibular dysfunction.*     

Additional General Exclusion Criteria for 7T task fMRI:

All subjects and controls will be excluded from undergoing the task fMRI scan if they have:

  • Active implant devices such as cardiac defibrillators/pacemakers, heart monitors, cohlear implants.
  • Abandoned cardiac pacer wires.
  • Orthopedic implants that are near the spinal cord or temperature sensitive organs.
  • Metallic implants near the orbits.
  • External devices that cannot be removed from the body (such as medicinal patches, piercings, jewelry, clothing or hair accessories).
  • Temporary tattoos or those obtained prior to 1995.
  • Colored contact lens.
  • Any ‘undefined’ metallic implants of foreign bodies inside the patient.
  • Are pregnant.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Adil Bharucha, M.B.B.S., M.D.

Open for enrollment

Contact information:

Kelly Feuerhak CCRP

(507) 255-6802


More information


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