GENERAL INFORMATION

It is an expectation that all patients receive care/services from a licensed clinician. All appropriate supporting documentation, including recent pertinent office visit notes, laboratory data, and results of any special testing must be provided. If applicable: All prior relevant imaging results and the reason that alternative imaging cannot be performed must be included in the documentation submitted.

Where a specific clinical indication is not directly addressed in this guideline, medical necessity determination will be made based on widely accepted standard of care criteria. These criteria are supported by evidence-based or peer-reviewed sources such as medical literature, societal guidelines and state/national recommendations.

Policy 
INDICATIONS FOR CHEST MRI

The combination of superior soft tissue contrast and lack of ionizing radiation may make chest magnetic resonance imaging (MRI) preferable for the pediatric population, during pregnancy and also when frequent serial imaging is needed. This must be weighed against a longer acquisition time, greater likelihood of patient motion artifact as well as the lack of experience in obtaining and interpreting non-vascular chest MR. Recent technological advancements have made non-vascular thoracic MRI increasingly utilized; however, chest computed tomography (CT) is generally better for lung parenchymal evaluation at this time. Chest magnetic resonance angiography (MRA) is ordered for evaluation of the intrathoracic blood vessels.

Chest MRI and chest MRA should not be approved at the same time.

Chest Mass (non-lung parenchymal)^{1,2,3,4,5,6,7}

• Mass or lesion, including lymphadenopathy, after non-diagnostic x-ray or ultrasound (Chest CT indicated for pulmonary nodule)
• Thymoma screening in Myasthenia Gravis patients⁸
• Congenital thoracic malformation on other imaging (chest x-ray, echocardiogram, gastrointestinal study, or inconclusive CT)^9,10,11,12

Chest Wall (MRI preferred over CT):

• Pain (after initial evaluation with chest x-ray and/or rib films)
• History of known or suspected cancer involving the chest wall
• Signs and symptoms of infection with concern for chest wall involvement, such as: fever, elevated inflammatory markers, known infection at other sites
• Suspected chest wall injuries (including musculotendinous, costochondral cartilage, sternoclavicular joint, and manubriosternal joint injuries) when imaging will potentially alter management
• Malformations (such as pectus excavatum, pectus carinatum, scoliosis) in patients with cardiorespiratory symptoms for whom treatment is being considered
• Mass or lesion after inconclusive initial imaging (MRI preferred over chest CT for chest wall mass)

Brachial Plexopathy^13,14

• If mechanism of injury or electromyography/nerve conduction velocity (EMG/NCV) studies are suggestive
• Chest MRI is preferred study, but neck and/or shoulder (upper extremity) MRI can be ordered depending on the suspected location of injury

Cystic Fibrosis¹⁵

• Can be an alternative to chest CT to evaluate perfusion abnormalities, bronchiectasis, and mucus plugging if needed for treatment planning

Vascular diseases are better evaluated with chest CTA or MRA¹⁶

• Superior vena cava (SVC) syndrome¹⁷
• Subclavian steal syndrome after positive or inconclusive ultrasound^18,19
• Thoracic outlet syndrome^16,20,21
• Takayasu’s arteritis²²
• Acute or chronic aortic dissection^23,24
• Pulmonary hypertension — To evaluate for cause after echocardiogram or right heart catheterization^25,26

Congenital malformations

• Congenital heart disease with pulmonary hypertension²⁷
• Pulmonary sequestration²⁸

Atrial fibrillation with ablation planned²⁹

Preoperative/procedural evaluation
 

• Pre-operative evaluation for a planned surgery or procedure

Post-operative/procedural evaluation

• Post-surgical follow-up when records document medical reason requiring additional imaging

Other Indications
Further evaluation of indeterminate findings on prior imaging (unless follow up is otherwise specified within the guideline):

• For initial evaluation of an inconclusive finding on a prior imaging report that requires further clarification
• One follow-up exam of a prior indeterminate MR/CT finding to ensure no suspicious interval change has occurred. (No further surveillance unless specified as highly suspicious or change was found on last follow-up exam.)
   

Background
Magnetic resonance imaging (MRI) is a noninvasive imaging technique for detection and evaluation of various disease and conditions in the chest, e.g., congenital anomalies and aneurysms. MRI may be used instead of computed tomography (CT) in patients with allergies to radiographic contrast or with impaired renal function. Also, to decrease radiation exposure, Chest MRI may be used rather than CT when repeated imaging is expected (i.e., surveillance).

Overview 
MRI for Non-Parenchymal Masses³⁰
CT and MRI are similar in usefulness when imaging the chest wall and pleura. The main advantages of MRI are lack or radiation, superior contrast resolution for delineation of anatomy, evaluation of local invasion, greater ability to image in “unconventional planes” and real time imaging capabilities. CT is still the gold standard for evaluation parenchymal disease; however, MR is also now being considered in the assessment of endometriosis, lung nodules and lung cancer staging. The lack of standardized protocols and experience in interpretation still limits the usefulness of non-vascular chest MRI.

Due to the capability of MR to distinguish certain fat and fluid characteristics, MR can be superior to CT for evaluating mediastinal masses. The presence of microscopic fat allows MR to distinguish thymic hyperplasia from mass. Similarly, because of macroscopic fat, MR is useful in evaluating dermoid cysts teratomas, thymolipomas, lipomas and liposarcomas.

MRI can also differentiate simple from complex cystic lesions better than CT, and is thus useful for evaluating cystic mediastinal masses, such as thymic, foregut duplication or pericardial cysts and lymphatic malformations.
 
Finally, MRI can help differentiate types of neurogenic tumors (schwannomas, neurofibromas and ganglioneuromas) that may have similar CT features, to evaluate of intraspinal and neural extension of the tumor, as well as to assess adherence or invasion of a mediastinal mass to adjacent structures.

MRI and myasthenia gravis — Myasthenia gravis is a chronic autoimmune disease characterized by weakness of the skeletal muscles causing fatigue and exhaustion that is aggravated by activity and relieved by rest. It most often affects the ocular and other cranial muscles and is thought to be caused by the presence of circulating antibodies. Symptoms include ptosis, diplopia, chewing difficulties, and dysphagia. Thymoma has a known association with myasthenia. Contrast-enhanced MRI may be used to identify the presence of a mediastinal mass suggestive of myasthenia gravis in patients with renal failure or allergy to contrast material.

MRI and thoracic outlet syndrome — Thoracic outlet syndrome is a group of disorders involving compression at the superior thoracic outlet that affects the brachial plexus, the subclavian artery, and veins. It refers to neurovascular complaints due to compression of the brachial plexus or the subclavian vessels. Magnetic resonance multi-plane imaging shows bilateral images of the thorax and brachial plexus and can demonstrate the compression of the brachial plexus and venous obstruction.

MRI and brachial plexus — MRI is the only diagnostic tool that accurately provides high resolution imaging of the brachial plexus. The brachial plexus is formed by the cervical ventral rami of the lower cervical and upper thoracic nerves which arise from the cervical spinal cord, exit the bony confines of the cervical spine, and traverse along the soft tissues of the neck, upper chest, and course into the arms.
 

References 

18. Osiro S, Zurada A, Gielecki J, Shoja MM, Tubbs RS, Loukas M. A review of subclavian steal syndrome with clinical correlation. Med Sci Monit. May 2012;18(5):Ra57-63. doi:10.12659/msm.882721
19. Potter BJ, Pinto DS. Subclavian steal syndrome. Circulation. Jun 3 2014;129(22):2320-3. doi:10.1161/circulationaha.113.006653
20. Chavhan GB, Batmanabane V, Muthusami P, Towbin AJ, Borschel GH. MRI of thoracic outlet syndrome in children. Pediatr Radiol. Sep 2017;47(10):1222-1234. doi:10.1007/s00247-017- 3854-5
21. Povlsen S, Povlsen B. Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions. Diagnostics (Basel). Mar 20 2018;8(1)doi:10.3390/diagnostics8010021
22. Keser G, Direskeneli H, Aksu K. Management of Takayasu arteritis: a systematic review. Rheumatology (Oxford). May 2014;53(5):793-801. doi:10.1093/rheumatology/ket320
23. Barman M. Acute aortic dissection. ESC e-J Cardio Pract. 2014;12(25):02Jul2014. doi:https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-12/Acute- aortic-dissection
24. American College of Radiology. ACR Appropriateness Criteria® Thoracic Aorta Interventional Planning and Follow-up. American College of Radiology. Updated 2017. Accessed November 20, 2022. https://acsearch.acr.org/docs/3099659/Narrative/
25. Ascha M, Renapurkar RD, Tonelli AR. A review of imaging modalities in pulmonary hypertension. Ann Thorac Med. Apr-Jun 2017;12(2):61-73. doi:10.4103/1817-1737.203742
26. Rose-Jones LJ, McLaughlin VV. Pulmonary hypertension: types and treatments. Curr Cardiol Rev. 2015;11(1):73-9. doi:10.2174/1573403x09666131117164122
27. Pascall E, Tulloh RM. Pulmonary hypertension in congenital heart disease. Future Cardiol. Jul 2018;14(4):343-353. doi:10.2217/fca-2017-0065
28. Sancak T, Cangir AK, Atasoy C, Ozdemir N. The role of contrast enhanced three-dimensional MR angiography in pulmonary sequestration. Interact Cardiovasc Thorac Surg. Dec 2003;2(4):480-2. doi:10.1016/s1569-9293(03)00118-x
29. Kolandaivelu A. Role of Cardiac Imaging (CT/MR) Before and After RF Catheter Ablation in Patients with Atrial Fibrillation. J Atr Fibrillation. Aug-Sep 2012;5(2):523. doi:10.4022/jafib.523
30. Nguyen ET, Bayanati H, Bilawich AM, et al. Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Clinical Practice Guidance for Non-Vascular Thoracic MRI. Can Assoc Radiol J. Nov 2021;72(4):831-845. doi:10.1177/0846537121998961

Coding Section 

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community,  and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

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