An observational study in Cavernous Sinus Syndrome, sponsored by Post Graduate Institute of Medical Education and Research, Chandigarh. Active, not recruiting at 1 site in India. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-05.
Sponsored by Post Graduate Institute of Medical Education and Research, Chandigarh · Observational
The goal of this observational study is to evaluate the diagnostic utility of whole-body ⁶⁸Ga-FAPI PET/CT in adults with cavernous sinus syndrome (CSS) in whom magnetic resonance imaging (MRI) failed to establish the underlying cause. The study also compares the performance of ⁶⁸Ga-FAPI PET/CT with paired ¹⁸F-FDG PET/CT.
The main questions it aims to answer are:
Can whole-body ⁶⁸Ga-FAPI PET/CT detect and characterize cavernous sinus lesions and disease extent in patients with MRI-indeterminate CSS? Does ⁶⁸Ga-FAPI PET/CT provide superior lesion conspicuity and help identify safer biopsy sites compared with ¹⁸F-FDG PET/CT? Researchers will compare whole-body ⁶⁸Ga-FAPI PET/CT with paired ¹⁸F-FDG PET/CT to evaluate lesion detection, quantitative imaging parameters, disease extent, and their impact on identifying appropriate biopsy targets.
Cavernous sinus syndrome (CSS) is a clinically heterogeneous condition resulting from involvement of the cavernous sinus and its neurovascular contents. Although contrast-enhanced magnetic resonance imaging (MRI) is the imaging modality of choice for evaluating cavernous sinus pathology, it frequently cannot establish the underlying etiology because infectious, inflammatory, and neoplastic disorders often demonstrate overlapping imaging appearances. Establishing a tissue diagnosis is further complicated by the technical difficulty and potential risks associated with direct cavernous sinus biopsy. Consequently, identification of contiguous disease extension or extracranial lesions that can be safely sampled is an important component of the diagnostic work-up.
This prospective observational study evaluates the diagnostic utility of whole-body 68Ga-FAPI-46 PET/CT in adult patients with cavernous sinus syndrome in whom MRI failed to establish an etiological diagnosis. All enrolled participants undergo paired whole-body 18F-FDG PET/CT and 68Ga-FAPI-46 PET/CT prior to initiation of definitive therapy. The interval between the two PET/CT examinations does not exceed six days. MRI is performed as part of the standard diagnostic evaluation before PET/CT imaging.
The study compares the two PET tracers with respect to:
Detection of cavernous sinus lesions. Delineation of locoregional disease extension, including meningeal, pituitary/sellar, skull base, orbital, sinonasal, and adjacent soft-tissue involvement.
Detection of extracranial disease. Quantitative imaging parameters, including lesion SUVmax, background brain SUVmean, and target-to-background ratio (TBR).
Ability to identify safer and more accessible biopsy targets that may facilitate histopathological diagnosis.
PET/CT images are independently interpreted by experienced nuclear medicine physicians who are aware of the clinical presentation and MRI findings but blinded to the final diagnosis. Lesion uptake, disease distribution, and extracranial findings are assessed qualitatively, while SUVmax, background brain SUVmean, and TBR are measured for quantitative comparison. Final diagnosis is established using histopathological examination whenever feasible or established clinicoradiological diagnostic criteria when tissue confirmation is unavailable. Biopsy sites are selected following multidisciplinary discussion based on accessibility, anticipated diagnostic yield, and procedural safety. Participants are subsequently followed after initiation of etiology-directed therapy to document clinical and imaging response.
Statistical analyses include paired comparison of quantitative PET parameters using the Wilcoxon signed-rank test, comparison of lesion detection rates using the McNemar test, and comparison of quantitative imaging parameters between fungal infection and IgG4-related disease using the Mann-Whitney U test. Statistical significance is defined as a two-sided P value \<0.05.
72 studies on the registry are indexed under Immunoglobulin G4-Related Disease; 40 are open to participants now.
This study's enrollment of 21 is below the median of 124 across 19 observational studies indexed under Immunoglobulin G4-Related Disease.
Browse Immunoglobulin G4-Related Disease studies →Post Graduate Institute of Medical Education and Research, Chandigarh is the lead sponsor of 298 studies on the registry; 45 are open to participants now.
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The study population consisted of consecutive adult patients presenting with clinically diagnosed cavernous sinus syndrome (CSS) at a tertiary care academic referral center between January 2023 and May 2024. Eligible participants had contrast-enhanced MRI demonstrating cavernous sinus pathology but without a definitive etiological diagnosis. All participants underwent paired whole-body ¹⁸F-FDG PET/CT and ⁶⁸Ga-FAPI-46 PET/CT prior to initiation of definitive therapy as part of the diagnostic evaluation.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Diagnostic Test: FAPI tracer · Drug: FDG-PET
Pilot study evaluating the role of FAPI PET/CT in Cavernous sinus syndrome
Whole-body ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT performed after at least 6 hours of fasting and confirmation of blood glucose \<200 mg/dL. ¹⁸F-FDG was administered intravenously at a dose of 3.7 MBq/kg body weight. Imaging was acquired approximately 60 minutes after tracer injection from the vertex to mid-thigh with an additional dedicated brain acquisition. This served as the comparator imaging modality for paired evaluation with ⁶⁸Ga-FAPI-46 PET/CT.
Diagnostic performance of ⁶⁸Ga-FAPI PET/CT for detection of cavernous sinus lesions compared with paired ¹⁸F-FDG PET/CT
Comparison of cavernous sinus lesion detection rates between whole-body ⁶⁸Ga-FAPI PET/CT and paired ¹⁸F-FDG PET/CT on a lesion basis using the McNemar test. A lesion is considered positive when tracer uptake exceeds adjacent background
Time frame: Baseline (prior to initiation of definitive therapy; both PET/CT examinations performed within 6 days of each other).
Comparison of lesion target-to-background ratio (TBR) between ⁶⁸Ga-FAPI PET/CT and ¹⁸F-FDG PET/CT
Comparison of lesion TBR calculated as lesion SUVmax divided by background brain SUVmean for paired lesions.
Time frame: Baselines
Comparison of lesion SUVmax between ⁶⁸Ga-FAPI PET/CT and ¹⁸F-FDG PET/CT
Comparison of maximum standardized uptake value (SUVmax) of paired cavernous sinus lesions between the two PET tracers.
Time frame: Baseline
Proportion of participants in whom ⁶⁸Ga-FAPI PET/CT identified an alternative biopsy site
Percentage of participants in whom whole-body ⁶⁸Ga-FAPI PET/CT identified a safer and more accessible contiguous or extracranial lesion suitable for tissue diagnosis instead of direct cavernous sinus biopsy.
Time frame: Baseline
Detection of clinically relevant extracranial disease by whole-body ⁶⁸Ga-FAPI PET/CT
Number of participants with disease-related extracranial lesions identified on whole-body ⁶⁸Ga-FAPI PET/CT
Time frame: Baseline
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Immunoglobulin G4-Related Disease →
Post Graduate Institute of Medical Education and Research, Chandigarh →