Prospective Paired Evaluation of Conventional Versus Structured Magnetic Resonance Imaging Interpretation for Preoperative Assessment of Gluteal Permanent Synthetic Filler Disease

N/ANot Yet RecruitingNCT07808463

Research Inc200 enrolled

Overview

This prospective paired diagnostic-impact study will compare conventional qualitative MRI reporting with a new structured anatomic classification in adults undergoing surgery for gluteal permanent synthetic filler disease. The structured report will document material effects across superficial, deep, muscular, regional, lymphatic, and interstitial compartments. Standardized intraoperative mapping will serve as the reference standard. The main outcome is the difference in sensitivity for surgically confirmed compartment involvement

Eligible participants will undergo a standardized pelvic and gluteal MRI before planned filler-removal surgery. The same examination will be interpreted using two prespecified formats: a conventional qualitative report and a structured report that grades involvement of the fat-fascia interface, subcutaneous fat, deep fascia, gluteal muscles, subcrestal, ischial, trochanteric, and pelvic-ring regions, as well as lymphatic and interstitial pathways. The operating surgeon will record a preliminary plan and utility rating after each report. During surgery, actual compartment involvement will be documented using a standardized map and, when available, specimen and histopathologic findings. Paired diagnostic performance, inter-reader agreement, change in surgical planning, and associations with operative complexity will be analyzed.

Study Type

OBSERVATIONAL

Enrollment

200

Conditions

Foreign-Body Reaction Soft Tissue Filler Complication Gluteal Permanent Synthetic Filler Disease

Interventions

Conventional Qualitative MRI InterpretationDIAGNOSTIC_TEST

The report records the presence or absence of injected foreign material in the gluteal region and any routinely reported findings. A preliminary surgical plan is recorded after review of this report. Linked arm/group(s): Paired MRI Interpretation Cohort.

Structured Gluteal Filler MRI ClassificationDIAGNOSTIC_TEST

The report records material distribution and severity in predefined compartments: fat-fascia interface, subcutaneous fat, deep fascia, gluteal muscles, subcrestal region, ischial region, trochanteric region, pelvic ring, lymphatic pathways, and interstitial involvement. The final classification manual and grade definitions will be locked before enrollment. Linked arm/group(s): Paired MRI Interpretation Cohort.

Standardized Intraoperative Anatomic MappingPROCEDURE

During the index operation, the surgeon documents actual involvement of each predefined compartment before reviewing the imaging accuracy analysis. Operative photographs, specimen mapping, and histopathology may support the reference standard. Linked arm/group(s): Paired MRI Interpretation Cohort.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age 18 years or older. * History of gluteal injection with a permanent or unknown nonresorbable filler. * Preoperative pelvic/gluteal MRI performed using the study acquisition protocol. * Planned surgical removal, biopsy, or operative exploration within 90 days after MRI. * Written informed consent for paired image interpretation and use of operative findings. Exclusion Criteria: * MRI contraindication or nondiagnostic imaging caused by motion or incomplete anatomic coverage. * Prior extensive gluteal filler removal that prevents mapping of the predefined compartments. * No operative procedure within 90 days after MRI and therefore no reference-standard assessment. * Acute life-threatening infection or emergency surgery that prevents completion of the preoperative reporting sequence. * Inability to provide consent.

Outcomes

Primary Outcomes

Sensitivity for Surgically Confirmed Anatomic Compartment Involvement

For each reporting method, sensitivity is the number of predefined compartments identified as involved on MRI divided by the number confirmed as involved during standardized intraoperative mapping. The structured and conventional results will be compared within the same participant.

Time frame: Preoperative MRI interpretation and the index surgical procedure performed within 90 days after MRI. 90 days

Secondary Outcomes

Specificity for Surgically Uninvolved Anatomic Compartments

For each method, specificity is the number of compartments correctly identified as uninvolved on MRI divided by the number documented as uninvolved at surgery.

Time frame: Preoperative MRI interpretation and the index surgical procedure performed within 90 days after MRI. 90 dys

Change in Preoperative Surgical Plan After Structured MRI Review

Proportion of participants for whom the recorded operative plan changes after the structured report, including planned incision, extent of excision, anticipated deep-plane dissection, lymphatic evaluation, or reconstruction strategy.

Time frame: Immediately after the conventional report and immediately after the structured report, both before surgery. 1 day

Surgeon-Rated MRI Report Utility

The operating surgeon rates completeness, anatomic clarity, confidence, and usefulness for planning on prespecified 0-to-10 scales after each report. Higher scores indicate greater perceived utility.

Time frame: Immediately after review of each preoperative MRI report. 1 day