Microvasculature Ultrasound Super-resolution in Transplant Delayed Graft Function (MUST-D)

June 8, 2026 updated by: Roderick Tan

This pilot study is testing a new ultrasound imaging method called Super-Resolution Ultrasound (SRU) to look at blood flow and tiny blood vessels in transplanted kidneys in very detailed images after kidney transplant surgery. The goal is to see whether changes in the kidney's small blood vessels can help predict how well the transplanted kidney will work early after transplant, including whether delayed graft function may occur.

Investigators hope this technique can become a safe, noninvasive way to evaluate transplanted kidneys without needing as many invasive biopsies. It may also help doctors better assess donor kidneys at higher-risk of suboptimal functioning.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Specific Aim 1: Utilize super-resolution ultrasound (SRU) to analyze tiny blood vessels in transplanted kidneys under very detailed imaging and evaluate kidney allografts and predict post-transplantation function.

Delayed graft function (DGF) is a common complication that can happen soon after a kidney transplant and may lead to longer recovery times and other health problems. Kidney biopsies are typically required to find the cause, which are invasive procedures. Current imaging tests cannot clearly show the tiny blood vessel changes inside the transplanted kidney that may contribute to the development of DGF.

Hypothesis: Investigators hypothesize that SRU can noninvasively predict DGF outcomes by measuring changes in the structure of tiny kidney blood vessels and the blood flow within them.

Approach:

Aim 1a: Compare SRU-derived measures of renal microvasculature-including microvascular density, tortuosity, and cortical perfusion-between patients who develop DGF and those with uncomplicated graft function.

Aim 1b: Correlate SRU parameters with clinical outcomes at 30 and 90 days post-transplant, as determined from inpatient and outpatient data within the electronic medical record.

Experimental Plan. Allograft SRU will be performed in 20 renal allograft recipient patients up to 14 days after transplant (n=10 with DGF, n=10 without DGF). Patients will be identified and recruited from within UPMC. After injection with Definity, SRU images and measurements will be obtained as described elsewhere in this protocol. Measures are noninvasive, with the transducer applied to the body surface over the allograft. Measurements will be compared between the two groups, and correlations made with eGFR at 30 and 90 days, total days of dialysis, resistive indices, and interstitial fibrosis/tubular atrophy (IFTA) on the standard 3-month protocol biopsy.

Anticipated Results, Potential Pitfalls, and Future Directions. Investigators expect that renal blood volume and microvessel density will be higher in patients with functioning grafts, and that these parameters will be positively correlated with better outcomes, demonstrating that SRU is a promising and noninvasive prognostic tool.

Expected Outcomes and Impact: Investigators anticipate that SRU will identify microvascular densities predictive of DGF, providing a novel, noninvasive biomarker to guide post-transplant management. Successful completion of this aim will establish SRU as a clinically useful tool to reduce reliance on invasive biopsy and improve early allograft evaluation.

Specific Aim 2: Utilize super-resolution ultrasound (SRU) to evaluate early microvascular changes in high-KDPI kidneys up to 14 days after transplantation to predict early graft function.

Rationale: Donor kidneys with a high Kidney Donor Profile Index (KDPI) are often discarded due to their perceived risk of poor function, despite limited physiologic data on their microvascular integrity. Early post-transplant microvascular alterations may serve as critical indicators of graft viability and short-term function.

Hypothesis: Investigators hypothesize that SRU-detected microvascular changes occurring within the first 48 hours after transplantation can predict early transplanted kidney function and distinguish between high- and low-KDPI kidneys.

Experimental Plan:

Investigators will perform SRU imaging within 14 days of transplantation in kidney allograft recipients, using the same SRU parameters described in Aim 1. Investigators will compare SRU-derived measures such as structure, size, characteristics, and blood flow -between two groups: recipients of high-risk kidneys (KDPI >75; n = 10) and recipients of more optimal kidneys (KDPI <35; n = 10). SRU findings will be correlated with key clinical outcomes, including the incidence of delayed graft function (DGF), need for dialysis, measures of kidney function at 30 and 90 day marks, and the degree of scarring of the functional units of the kidney observed on 90-day protocol biopsies.

Anticipated Results, Potential Pitfalls, and Future Directions:

Investigators anticipate that kidneys with higher KDPI values will demonstrate reduced vascular density and perfusion within 48 hours post-transplant, and that these findings will correlate with inferior 30- and 90-day outcomes. If no significant differences or correlations are observed, investigators will reconsider the utility of the 48-hour timepoint in future studies or examine whether recipient-specific factors (e.g., age, hemodynamic status, blood pressure) influence SRU measurements. Findings from this aim will inform whether SRU can serve as an early, noninvasive measurement of transplanted kidney quality and may challenge current allocation practices that exclude high-KDPI kidneys (high-risk of suboptimal functioning kidneys)

Study Type

Observational

Enrollment (Estimated)

40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Roderick J Tan, MD, PHD
  • Phone Number: 4126244008
  • Email: tanrj@upmc.edu

Study Contact Backup

Study Locations

  • United States
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • University of Pittsburgh Medical Center
        • Contact:
          • Roderick J Tan, MD, PHD
          • Phone Number: 4126244008
          • Email: tanrj@upmc.edu
        • Contact:
        • Sub-Investigator:
          • Kang Kim, PHD
        • Sub-Investigator:
          • George F Viriya, MD
        • Principal Investigator:
          • Roderick J Tan, MD, PHD
        • Sub-Investigator:
          • Mohit Madken, MD
        • Sub-Investigator:
          • Jihoon Park, MD, PHD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients with end stage kidney disease who are receiving deceased donor kidney allograft transplants who meet the inclusion and exclusion criteria

Description

Inclusion Criteria:

For stage 1 of the study:

  1. We will enroll patients ≥18 years of age
  2. Patients who received a kidney transplant 2a. Patients requiring dialysis in the first 14 days after transplant 2b. Patients with working allografts not requiring dialysis (control group)

For stage 2 of the study

  1. We will enroll patients at least 18 years of age or older
  2. Patients who received a kidney transplant 2a. Patients who received kidney transplants from low KDPI kidneys (KDPI < 35) 2b. Patients who received kidney transplants from high KDPI kidneys (KDPI > 75)

Exclusion Criteria:

  1. BMI > 40
  2. Inability to provide informed consent
  3. Pregnant woman
  4. Breastfeeding women
  5. Hypersensitivity to perfluten lipid microsphere and components including polyethylene glycol (PEG)
  6. Unstable cardiopulmonary condition (acute myocardial infarction, acute coronary artery symptoms, worsening or unstable congestive heart failure, serious ventricular arrhythmias).
  7. Known history of cardiac shunts
  8. Patients who have known sickle cell disease or trait

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
High KDPI
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant with High KDPI allografts
Diagnostic test: Ultrasound contrast agent (Contrast-enhanced ultrasound)
Super-resolution ultrasound using lipid microsphere contrast
Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension)
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: Lumason® contrast agent
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: DEFINITY®
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Low KDPI
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant with Low KDPI allografts
Diagnostic test: Ultrasound contrast agent (Contrast-enhanced ultrasound)
Super-resolution ultrasound using lipid microsphere contrast
Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension)
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: Lumason® contrast agent
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: DEFINITY®
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Delayed Graft Function
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant who require renal replacemen therapy within 2 weeks after transplant.
Diagnostic test: Ultrasound contrast agent (Contrast-enhanced ultrasound)
Super-resolution ultrasound using lipid microsphere contrast
Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension)
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: Lumason® contrast agent
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: DEFINITY®
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Non-delayed Graft Function
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant who do not require renal replacemen therapy within 2 weeks after transplant.
Diagnostic test: Ultrasound contrast agent (Contrast-enhanced ultrasound)
Super-resolution ultrasound using lipid microsphere contrast
Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension)
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: Lumason® contrast agent
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Drug: DEFINITY®
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Kidney vascularity
Time Frame: Less than 30 minutes
Assessment of total renal vascularity and measures of perfusion. Images obtained with the kidney ultrasound will be analyzed for total number of blood vessels and blood perfusion detected in different regions of the kidney.
Less than 30 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Kidney blood vessel tortuosity
Time Frame: up to 30 minutes
While the total number of blood vessels may differ between subjects, it is also possible that the number of blood vessel branches may be different.
up to 30 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Roderick Tan

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

June 30, 2028

Study Completion (Estimated)

June 30, 2028

Study Registration Dates

First Submitted

June 8, 2026

First Submitted That Met QC Criteria

June 8, 2026

First Posted (Actual)

June 12, 2026

Study Record Updates

Last Update Posted (Actual)

June 12, 2026

Last Update Submitted That Met QC Criteria

June 8, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY25100091

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Patient data such as demographics, test results, medical chart data, and data acquired from imaging including vessel density, cortical perfusion, and vessel branching.

IPD Sharing Time Frame

June 1, 2026 until June 30, 2030

IPD Sharing Access Criteria

Researchers with ideas for studies using our data may request it from the study PI.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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