What diseases require a high Tesla (Magnetic Resonance Imaging) MRI where an Inspire (Upper Airway Stimulation) device for sleep apnea may be problematic?

Diseases Requiring High Tesla MRI Where Inspire Device Would Be Problematic

Multiple sclerosis, neuromyelitis optica spectrum disorders, leptomeningeal metastases, and malignant pleural mesothelioma are diseases that require high Tesla (≥1.5T) MRI for accurate diagnosis and monitoring, where an Inspire upper airway stimulation device would be problematic due to MRI incompatibility.

Multiple Sclerosis and Related Demyelinating Disorders

• Multiple sclerosis (MS) diagnosis and monitoring requires high-field MRI (≥1.5T) to detect characteristic lesions with sufficient resolution, as lower field strengths may miss small lesions or fail to properly characterize them 1
• High-field MRI (3.0T) allows detection of significantly more lesions in clinically isolated syndrome patients, with improved recognition of cortical, infratentorial, and periventricular lesions compared to lower field strengths 1
• Ultra-high-field MRI (7.0T) provides better definition of MS lesions with respect to their morphology and association with the vasculature, showing distinctive features like central veins and hypointense rims that help differentiate MS from other conditions 1
• The presence of a central small vein and rim of hypointensity on T2*-weighted imaging at high field strengths is a distinctive feature of MS lesions that helps differentiate them from neuromyelitis optica spectrum disorders (NMOSD) or Susac syndrome 1

Neuromyelitis Optica Spectrum Disorders

• Diagnosis of NMOSD requires high-quality MRI of the brain, optic nerve, and spinal cord to detect characteristic lesions and distinguish from MS 1
• For AQP4-IgG negative patients or those with unknown AQP4-IgG status, specific MRI findings are essential for diagnosis, including optic nerve lesions extending over half the nerve length or involving the optic chiasm 1
• Longitudinally extensive transverse myelitis (LETM), a hallmark of NMOSD, requires high-quality MRI to detect intramedullary lesions extending over 3 contiguous segments 1
• High-field MRI helps differentiate NMOSD from MS by showing the absence of slowly evolving lesions with hypointense rims, which are common in MS 1

Leptomeningeal Metastases

• Leptomeningeal metastases require high-quality MRI of the entire neuroaxis (brain and total spine) with and without contrast for accurate diagnosis and monitoring 1
• Technical imaging recommendations specifically call for 1.5T and 3T MRI scanners only, with consistency of scanner between diagnosis and surveillance 1
• 3D T1 post-contrast images with isotropic 1mm voxels and reformatted slice thickness of 3mm are required to enhance detection of small leptomeningeal deposits 1
• As a disease state encompassing the entire neuroaxis, lower field strength imaging would be inadequate for detecting small metastatic deposits 1

Malignant Pleural Mesothelioma

• MRI is crucial for determining the presence and extent of tumor invasion into the diaphragm, chest wall, and mediastinal structures in malignant pleural mesothelioma 1
• Both 1.5T and 3T field strengths are recommended, with 3T offering faster acquisition with higher spatial resolution, while 1.5T has reduced susceptibility artifacts 1
• Field strengths greater than 3T are not recommended due to increased susceptibility artifacts from air interfaces in the lung 1
• High-field MRI helps differentiate between T3 and T4 disease by detecting transdiaphragmatic invasion, which is critical for determining surgical eligibility 1

Rapidly Progressive Dementia

• High-field MRI is essential for detecting prion-related causes of rapidly progressive dementia such as Creutzfeldt-Jakob disease (CJD), which manifest as hyperintense signal on T2, FLAIR, and DWI sequences 1
• MRI at 1.5T or higher is needed to detect the "hockey stick" or "pulvinar" sign in variant CJD, which is more sensitive than CSF or EEG findings 1
• Structural MRI at high field strengths can depict specific atrophy patterns that could suggest atypical presentations of dementia 1
• High-field MRI is also crucial for detecting infectious, inflammatory, autoimmune, and malignancy-related conditions that can present as rapidly progressive dementia 1

Why Inspire Device is Problematic with High Tesla MRI

• The Inspire upper airway stimulation device contains metallic components that are not compatible with the strong magnetic fields used in high Tesla MRI 2
• Patients with obstructive sleep apnea who have been treated with the Inspire device would be unable to undergo necessary high-field MRI scans for the above conditions 2, 3
• This creates a clinical dilemma when patients with sleep apnea develop neurological or oncological conditions requiring high-field MRI diagnosis or monitoring 3, 4
• The magnetic fields in high Tesla MRI could potentially cause device displacement, malfunction, or heating of the Inspire device components, posing safety risks to patients 2, 4

Clinical Implications and Management Considerations

• For patients with sleep apnea who are at high risk for developing conditions requiring high-field MRI (such as those with risk factors for MS or cancer), alternative sleep apnea treatments should be considered 2, 3
• For patients who already have an Inspire device and develop symptoms suggestive of conditions requiring high-field MRI, alternative imaging modalities may need to be considered, though these may provide suboptimal diagnostic information 1
• In cases where high-field MRI is absolutely necessary for a patient with an Inspire device, a risk-benefit analysis should be performed, potentially considering device removal if the diagnostic information is critical 3, 4
• Patients with a history of neurological disorders that might require future high-field MRI monitoring should be counseled about this limitation before Inspire device implantation 2, 4