MRI of the thoracic spine

Standard and postoperative imaging protocols

For a comprehensive assessment of the thoracic spine structures, a standardized scanning approach is applied. Routine MRI protocol of the spine must invariably include the following sequences:

• Sagittal T1-weighted (sagittal T1);
• Sagittal T2-weighted (sagittal T2);
• Sagittal T2 with fat suppression (e.g., STIR — short TI inversion recovery sequence);
• Axial T2-weighted (axial T2).

Special attention is required for examination in the postoperative period. In this case, MRI significantly outperforms computed tomography (CT) in detecting postoperative fibrosis. For adequate visualization in such clinical scenarios, the protocol must be expanded: an axial T1-weighted sequence before and after intravenous administration of a paramagnetic gadolinium-based contrast agent (Gd) is added.

Imaging of infectious lesions: tuberculous spondylitis

Magnetic resonance imaging is a key modality in the differential diagnosis of specific spinal infections, such as tuberculous spondylitis (Tuberculous Spondylitis). On sagittal T1- and T2-weighted images, multilevel vertebral involvement is classically visualized. The inflammatory process spreads subligamentously (subligamentous extension).

A characteristic diagnostic sign of tuberculous involvement is the relative preservation of intervertebral discs (relative preservation of intervertebral discs), despite pronounced destruction of adjacent vertebrae.

When using contrast-enhanced MRI (axial T1-weighted image with gadolinium), multiple paravertebral abscesses can be clearly visualized. These represent so-called cold abscesses (cold abscesses), which spread subfascially and feature a characteristic thin enhancing rim (thin enhancing rim).

Diagnosis of intervertebral disc herniations

Imaging modalities, including MRI and reformatted CT images, allow for the precise localization of herniated discs and the assessment of their impact on neural structures.

In the thoracic region, a calcified thoracic disc extrusion (Calcified Thoracic Disc Extrusion) may be detected. On axial and sagittal slices, it is defined as a calcified upward herniation that causes clinically significant narrowing of the right lateral recess (narrowing of the right lateral recess).

In the lumbar region (e.g., at the L4–L5 level), extraforaminal herniations are frequently encountered. On axial T2-weighted MRI and CT scans, the herniation is seen extending into the intervertebral foramen (neuroforamen) and causing obliteration (compression or displacement) of the normal adipose tissue in this zone.

MRI compared to other diagnostic imaging modalities

Although MRI is the preferred modality for soft tissues, a comprehensive approach requires an understanding of the capabilities of adjacent methods:

1. Plain radiography (Plain radiography): Is no longer a definitive modality (replaced by MRI/CT). However, it remains indispensable for dynamic imaging in the erect position (erect position). In trauma, it helps determine the level of injury, although it misses up to 55% of cervical spine fractures.
2. Computed tomography (CT) (CT): Remains an adequate method for assessing spinal cord compression, anatomical details of posterior vertebral structures, facet joints (facet joints), and lytic destructive lesions with a zone of sclerosis.
3. SPECT/CT (SPECT/CT): Combines the detection of mechanical stress zones with the high spatial resolution of CT. The method outperforms MRI in assessing loosening of spinal fusion hardware and detecting osteomyelitis (visualizing hot spots — hot spots with gallium).
4. Spinal angiography (DSA) (DSA): Is still considered the "gold standard" for detailing spinal arteries due to its maximum spatial resolution.

Class and exam questions

What else to study on this topic

• JART mediastinal space classification (evaluation on axial slices)
• Capabilities of MRI and CT in the differential diagnosis of invasive and non-invasive thymomas
• Physiological 18F-FDG uptake by the thymus on PET/CT in young patients
• Specifics of the imaging appearance of fat-containing chest lesions
• Digital subtraction angiography (DSA) in the evaluation of spinal arteries

Other topics in the "Spine" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.