(Medicare National Coverage Determinations Manual)

Sufficient information must be provided with claims to differentiate CT scans from other radiology services and to make coverage determinations.  Carefully review claims to ensure that a scan is reasonable and necessary for the individual patient; i.e., the use must be found to be medically appropriate considering the patients symptoms and preliminary diagnosis.  There is no general rule that requires other diagnostic tests to be tried before CT scanning is used.  However, in an individual case the A/B MAC (A) or (B) medical staff may determine that use of a CT scan as the initial diagnostic test was not reasonable  and necessary because it was not supported by the patients symptoms or complaints stated on the claim form; e.g., periodic headaches."   Claims for CT scans are reviewed for evidence of abuse, which might include the absence of reasonable indications for the scans, an excessive number of scans, or unnecessarily expensive types of scans considering the facts in the particular cases.   C. Approved Models of CT Equipment   1. Criteria for Approval   In the absence of evidence to the contrary, the A/B MAC (A) or (B) may assume that a CT scan for which payment is requested has been performed on equipment that meets the following criteria:   a. The model must be known to the Food and Drug Administration (FDA), and  b. Must be in the full market release phase of development.   Should it be necessary to confirm that those criteria are met, ask the manufacturer to submit the information in C.2.  If manufacturers inquire about obtaining Medicare approval for their equipment, inform them of the foregoing criteria.   2. Evidence of Approval   a. The letter sent by the Bureau of Radiological Health, FDA, to the manufacturer acknowledging the FDAs receipt of information on the specific CT scanner system model submitted as required under Public Law 90- 602, The Radiation Control for Health and Safety Act of 1968."   b. A letter signed by the chief executive officer or other officer acting in a similar capacity for the manufacturer which:   i.. Furnishes the CT scanner system model number, all names that hospitals and physicians offices may use to refer to the CT scanner system on claims, and the accession number assigned by FDA to the specific model;   ii. Specifies whether the scanner performs head scans only, body scans only (i.e., scans of parts of the body other than the head), or head and body scans;   iii. States that the company or corporation is satisfied with the results of the developmental stages that preceded the full market release phase of the equipment, that the equipment is in the full market release phase, and the date on which it was decided to put the product into the full market release phase.  D. Mobile CT Equipment   CT scans performed on mobile units are subject to the same Medicare coverage requirements applicable to scans performed on stationary units, as well as certain health and safety requirements recommended by the Health Resources and Services Administration.  As with scans performed on stationary units, the scans must be determined medically necessary for the individual patient.  The scans must be performed on types of CT scanning equipment that have been approved for use as stationary units (see C above), and must be in compliance with applicable State laws and regulations for control of radiation.   1. Hospital Setting   The hospital must assume responsibility for the quality of the scan furnished to inpatients and outpatients and must ensure that a radiologist or other qualified physician is in charge of the procedure.  The radiologist or other physician (i.e., one who is  with the mobile unit) who is responsible for the procedure must be approved by the hospital for similar privileges.  2. Ambulatory Setting   If mobile CT scan services are furnished at an ambulatory health care facility other than a hospital -based facility, e.g., a freestanding physician- directed clinic, the diagnostic procedure must be performed by, or under the direct personal supervision of, a radiologist or other qualified physician.  In addition, the facility must maintain a record of the attending physicians order for a scan performed on a mobile unit.  3. Billing for Mobile CT Scans   Hospitals, hospital -associated radiologists, ambulatory health care facilities, and physician owner/operators of mobile units may bill for mobile scans as they would for scans performed on stationary equipment.   4. Claims Review   Evidence of compliance with applicable State laws and regulations for control of radiation should be requested from owners of mobile CT scan units upon receipt of the first claims.  All mobile scan claims should be reviewed very carefully in accordance with instructions applicable to scans performed on fixed units, with particular emphasis on the medical necessity for scans performed in an ambulatory setting.  E. Multi -Planar Diagnostic Imaging (MPDI)   In usual CT scanning procedures, a series of transverse or axial images are reproduced.  These transverse images are routinely translated into coronal and/or sagittal views.  MPDI is a process which further translates the data produced by CT scanning by providing reconstructed oblique images which can contribute to diagnostic information. MPDI, also known as planar image reconstruction or reformatted imaging, is covered under M edicare when provided as a service to an entity performing a covered CT scan.   F. Computed Tomographic Angiography (CTA)   CTA is a general phrase used to describe a non -invasive method, using intravenous contrast, to visualize the coronary arteries (or other vessels) using high- resolution, high-  speed CT.   After examining the medical evidence, the Centers for Medicare and Medicaid Services has determined that no national coverage determination is appropriate at this time (March 12, 2008).  Section 1862(a)(1)(A) of the Social Security Act decisions should be made by MACs through a local coverage determination process or case- by-case adjudication.  See Heckler v. Ringer , 466 U.S. 602, 617 (1984) (Recognizing that the Secretary has discretion to either establish a generally applicable rule or to allow individual adjudication.).  See also, 68 Fed. Reg. 63692, 63693 (November 7, 2003).    220.2 - Magnetic Resonance Imaging (MRI) (Various Effective Dates Below)  (Rev. 173, Issued: 09- 04-14, Effective: Upon Implementation: of ICD -10, Implementation: Upon Implementation of ICD -10)  A. General   1. Method of Operation   Magnetic Resonance Imaging (MRI), formerly called nuclear magnetic resonance (NMR), is a non-invasive method of graphically representing the distribution of water and other hydrogen -rich molecules in the human body.  In contrast to conventional radiographs or computed tomography (CT) scans, in which the image is produced by x- ray beam attenuation by an object, MRI is capable of producing images by several techniques.  In fact, various combinations of MRI image production methods may be employed to emphasize  particular characteristics of the tissue or body part being examined.  The basic elements by which MRI produces an image are the density of hydrogen nuclei in the object being examined, their motion, and the relaxation times, and the period of time required for the nuclei to return to their original states in the main, static  magnetic field after being subjected to a brief additional magnetic field.  These relaxation times reflect the physical- chemical properties of tissue and the molecular environment of its hydrogen nuclei.  Only hydrogen atoms are present in human tissues in sufficient concentration for current use in clinical MRI.   Magnetic Resonance Angiography (MRA) is a non- invasive diagnostic test that is an application of MRI. By analyzing the amount of energy released from tissues exposed to a strong magnetic field, MRA provides images of normal and diseased blood vessels, as w ell as visualization and quantification of blood flow through these vessels.   2. General Clinical Utility   Overall, MRI is a useful diagnostic imaging modality that is capable of demonstrating a wide variety of soft -tissue lesions with contrast resolution equal or superior to CT scanning in various parts of the body.   Among the advantages of MRI are the absence of ionizing radiation and the ability to achieve high levels of tissue contrast resolution without injected iodinated radiological contrast agents.  Recent advances in technology have resulted in development and Food and Drug Administration (FDA) approval of new paramagnetic contrast agents for MRI which allow even better visualization in some instances.  Multi- slice imaging and the ability to image in multiple planes, especially sagittal and coronal, have provide d flexibility not easily available with other modalities.  Because cortical (outer layer) bone and metallic prostheses do not cause distortion of MR images, it has been possible to visualize certain lesions and body regions with greater certainty than has been possible with CT.  The use of MRI on certain soft tissue structures for the purpose of detecting disruptive, neoplastic, degenerative, or inflammatory lesions has now become established in medical practice.   Phase contrast (PC) and time- of-flight (TOF) are some of the available MRA techniques at the time these instructions are being issued.  PC measures the difference between the phases of proton spins in tissue and blood and measures both the venous and arterial blood flow at any point in the cardiac cycle.  TOF measures the difference between the amount of magnetization of tissue and blood and provides information on the structure of blood vessels, thus indirectly indicating blood flow.  Two -dimensional (2D) and three- dimensional (3D) images can be obtained using each method.  Contrast -enhanced MRA (CE -MRA) involves blood flow imaging after the patient receives an intravenous injection of a contrast agent.  Gadolinium, a non- ionic element, is the foundation of all contrast agents currently in use.  Gadolinium affects the way in which tissues respond to magnetization, resulting in better visualization of structures when compared to un- enhanced studies.  Unlike ionic (i.e., iodine -based) contrast agents used in conventional contrast angiography (CA), allergic reactions to gadolinium are extremely rare.   Additionally, gadolinium does not cause the kidney failure occasionally seen with ionic contrast agents.  Digital subtraction angiography (DSA) is a computer -augmented form of CA that obtains digital blood flow images as contrast agent courses through a blood vessel.  The computer subtracts bone and other tissue from the image, thereby improving visualization of blood vessels.  Physicians elect to use a specific MRA or CA technique based upon clinical information from each patient.   B. Nationally Covered MRI and MRA Indications   1. MRI   Although several uses of MRI are still considered investigational and some uses are clearly contraindicated (see subsection C), MRI is considered medically efficacious for a number of uses.  Use the following descriptions as general guidelines or examples of what may be considered covered rather than as a restrictive list of specific covered indications.  Coverage is limited to MRI units that have received FDA premarket approval, and such units must be operated within the parameters specified by the approva l.  In addition, the services must be reasonable and necessary for the diagnosis or treatment of the specific patient involved.  a. Effective November 22, 1985, MRI is useful in examining the head, central nervous system, and spine.  Multiple sclerosis can be diagnosed with MRI and the contents of the posterior fossa are visible.  The inherent tissue contrast resolution of MRI makes it an appropriate standard diagnostic modality for general neuroradiology.  b. Effective November 22, 1985, MRI can assist in the differential diagnosis of mediastinal and retroperitoneal masses, including abnormalities of the large vessels such as aneurysms and dissection.  When a clinical need exists to visualize the parenchyma of solid organs to detect anatomic disruption or neoplasia, this can be accomplished in the liver, urogenital system, adrenals, and pelvic organs without the use of radiological contrast materials.  When MRI is considered reasonable and necessary, the use of paramagnetic contrast materials may be covered as part of the study.  MRI may also be used to detect and stage pelvic and retroperitoneal neoplasms and to evaluate disorders of cancellous bone and soft tissues.  It may also be used in the detection of pericardial thickening.  Primary and secondary bone neoplasm and aseptic necrosis can be detected at an early stage and monitored with MRI.  Patients with metallic prostheses, esp ecially of the hip, can be imaged in order to detect the early stages of infection of the bone to which the prosthesis is attached.   c. Effective March 22, 1994, MRI may also be covered to diagnose disc disease without regard to whether radiological imaging has been tried first to diagnose the problem.  d. Effective March 4, 1991, MRI with gating devices and surface coils, and gating devices that eliminate distorted images caused by cardiac and respiratory movement cycles are now considered state of the art techniques and may be covered.  Surface and other specialty coils may also be covered, as they are used routinely for high resolution imaging where small limited regions of the body are studied.  They produce high signal -to-noise ratios resulting in images of enhanced anatomic detail.   2. MRA (MRI for Blood Flow)   Currently covered indications include using MRA for specific conditions to evaluate flow in internal carotid vessels of the head and neck, peripheral arteries of lower extremities, abdomen and pelvis, and the chest.  Coverage is limited to MRA units that have received FDA premarket approval, and such units must be operated within the parameters specified by the approval.  In addition, the services must be reasonable and necessary for the diagnosis or treatment of the specific patient involved.   a. Head and Neck