This prospective comparative observational study evaluates image quality characteristics and short-term physiological effects associated with contrast-enhanced magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in patients with cervical and lumbar spinal pathologies.

A total of 120 adult participants undergo either contrast-enhanced MRI or FDG-PET/CT as part of routine clinical evaluation. Image quality is assessed using quantitative metrics, including signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), as well as qualitative Visual Grading Analysis (VGA) performed by blinded radiologists. Short-term physiological effects are evaluated using blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and hemoglobin measurements obtained before imaging and 48 hours after imaging.

The study aims to compare image quality characteristics and short-term physiological parameters associated with these imaging modalities and to examine the influence of age group and spinal region on imaging performance.

Background and Rationale

Magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) are widely used imaging modalities for the evaluation of cervical and lumbar spinal disorders. MRI primarily provides high-resolution anatomical information, whereas FDG-PET/CT provides metabolic and functional information that may assist in the assessment of inflammatory, infectious, degenerative, and neoplastic spinal conditions. Although both modalities are routinely used in clinical practice, differences in image quality characteristics and short-term physiological effects associated with imaging procedures remain areas of interest.

Study Design

This study is a prospective comparative observational study designed to evaluate image quality characteristics and short-term physiological effects associated with contrast-enhanced MRI and FDG-PET/CT in adult patients with cervical or lumbar spinal pathologies. A total of 120 participants are included, with 60 participants undergoing contrast-enhanced MRI and 60 participants undergoing FDG-PET/CT according to routine clinical indications and standard institutional workflows.

The study is non-interventional. No experimental treatments, investigational drugs, or deviations from standard clinical care are introduced. All imaging procedures are performed according to established institutional protocols and manufacturer recommendations.

Study Population

Eligible participants are adults with clinically suspected or confirmed cervical or lumbar spinal pathology requiring advanced imaging evaluation. Conditions may include degenerative, inflammatory, infectious, neoplastic, traumatic, or post-surgical spinal disorders.

Imaging Procedures

MRI examinations are performed using a 3 Tesla scanner equipped with a dedicated spinal coil. Standard spinal imaging protocols include sagittal and axial T1-weighted and T2-weighted sequences. Intravenous gadolinium-based contrast administration is performed according to institutional guidelines and standard clinical practice.

FDG-PET/CT examinations are performed following standard patient preparation procedures, including fasting requirements and blood glucose assessment. Intravenous administration of 18F-fluorodeoxyglucose (FDG) is followed by image acquisition using routine clinical PET/CT protocols. CT acquisition is used for attenuation correction and anatomical localization according to institutional practice.

Image Quality Assessment

Quantitative image quality assessment includes measurement of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) using standardized regions of interest. Measurements are performed using predefined image analysis procedures to ensure consistency across participants.

Qualitative image quality assessment is performed using Visual Grading Analysis (VGA). Independent blinded radiologists evaluate image quality using predefined criteria related to anatomical detail, tissue contrast, lesion conspicuity, image noise, and overall diagnostic usability.

Physiological and Safety Assessments

Short-term physiological effects associated with imaging procedures are evaluated using laboratory measurements obtained before imaging and 48 hours after imaging. Laboratory assessments include blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and hemoglobin concentration.

Routine safety monitoring is performed according to institutional standards. Adverse events associated with contrast administration or imaging procedures are documented and managed according to standard clinical protocols.

Subgroup Analyses

Prespecified subgroup analyses evaluate image quality metrics according to spinal region (cervical versus lumbar) and age group (50 years or younger versus older than 50 years). These analyses are intended to explore potential differences in imaging performance across clinically relevant patient subgroups.

Study Objectives

The primary objectives are to compare quantitative image quality metrics between contrast-enhanced MRI and FDG-PET/CT and to evaluate qualitative image quality using blinded radiologist assessment.

Secondary objectives include assessment of short-term changes in renal and hematologic laboratory parameters following imaging procedures performed as part of routine clinical care.

Ethics

The study is conducted in accordance with applicable ethical principles, institutional policies, and approved research protocols. Institutional Review Board approval has been obtained, and informed consent procedures are implemented as required by the approved protocol and applicable regulations.

Inclusion Criteria:

• Age 18 years or older.
• Clinically suspected or confirmed cervical or lumbar spinal pathology.
• Presence of symptoms suggestive of spinal disease, including radiculopathy, localized spinal pain, neurological deficits, or suspected metastatic involvement.
• Referred for diagnostic evaluation with contrast-enhanced MRI or FDG-PET/CT according to routine clinical indications.
• Availability of baseline clinical and laboratory data, including renal function assessment.
• Ability to provide informed consent.

Exclusion Criteria:

• Severe renal impairment (eGFR <30 mL/min/1.73 m²) or acute kidney injury.
• Known hypersensitivity to gadolinium-based contrast agents or 18F-FDG.
• Contraindications to MRI, including non-compatible metallic implants or severe claustrophobia.
• Pregnancy or breastfeeding.
• Uncontrolled diabetes mellitus (blood glucose >200 mg/dL at the time of PET/CT examination).
• Active systemic infection or inflammatory condition requiring immediate treatment.
• Inability to complete the required imaging procedures.
• Incomplete clinical, laboratory, or imaging data required for study evaluation.

Inclusion Criteria:

Age ≥ 18 years. Clinical symptoms suggestive of cervical or lumbar pathology (e.g., radiculopathy, localized pain, suspected metastasis).

Preliminary diagnostic suggestion from prior radiography or non-contrast CT.

Exclusion Criteria:

Severe renal impairment (estimated Glomerular Filtration Rate, eGFR < 30 mL/min/1.73m²) or history of acute kidney injury.

A total of 120 consecutive patients with clinically indicated cervical or lumbar spinal pathologies were enrolled. Patients were Known hypersensitivity to gadolinium-based metabolic tracerts or FDG. Standard contraindications to MRI (e.g., non-compatible metallic implants, severe claustrophobia).

Pregnancy or lactation. Uncontrolled diabetes mellitus (blood glucose >200 mg/dL at the time of PET/CT).

Active systemic infection or inflammatory condition requiring immediate treatment.Adverse Event Monitoring: Allergic reactions, NSF risk, radiation nau-sea tracked via CTCAE v5.0; no serious adverse events occurred

Participants will be recruited from the general population through community outreach, advertisements, and screening visits. Individuals who meet the eligibility criteria will be invited to participate.