Diagnosis of Osteoporotic Vertebral Fractures: Importance of Recognition and Description by Radiologists

Leon Lenchik; Lee F. Rogers; Pierre D. Delmas; Harry K. Genant

Disclosures

Am J Roentgenol. 2004;183(4) 

In This Article

Call to Action

Because of the serious clinical consequences of vertebral fractures, radiologists must make an effort to improve the accuracy of their diagnoses. They must also reduce the variability in terminology when describing vertebral fractures in patients with osteoporosis. The purpose of this section is to provide the basis for accurate radiologic interpretation and standardized reporting.

Accurate Interpretation

When evaluating imaging studies in which the vertebrae are included (i.e., not just spine radiography but also lateral chest radiography), the following questions are important.

Is there a fracture?—Vertebral fracture should be diagnosed when there is loss of height in the anterior, middle, or posterior dimension of the vertebral body that exceeds 20% (Fig. 1). Special effort should be made not to hedge on the diagnosis of vertebral fractures. If the radiologist cannot decide whether a fracture is present, additional views or additional imaging studies should be recommended. A radiologic hedge can adversely affect patient care by preventing a patient who would otherwise benefit from pharmacologic therapy from receiving it.

Figure 1.

Drawings show diagnosis and grading of vertebral fractures using semiquantitative method.[60] Vertebral fracture is diagnosed when reduction of height in anterior, middle, or posterior dimension of vertebral body exceeds 20%. Approximate degree of height reduction determines assignment of grade to vertebra. Fractures are classified as wedge, biconcave, or crush, depending on whether anterior, middle, or posterior portion of vertebral body is most diminished in height.

In addition to changes in dimension, vertebral fractures are detected on the basis of the presence of endplate deformities, the lack of parallelism of the endplates, and the general altered appearance compared with neighboring vertebrae (Fig. 2A, 2B, 2C). Radiologists should become familiar with pitfalls in the diagnosis of vertebral fractures. For example, poor technique in which the lateral projection is really an oblique projection may lead to the vertebrae appearing fractured (Fig. 3A, 3B). Similar pseudofractures may be seen on lateral projections in patients with scoliosis. Other abnormalities in vertebral shape may mimic a fracture. Examples include cupid's bow (a developmental variant), limbus vertebra (a developmental variant), Schmorl nodes (vertebral osteochondrosis or Scheuermann's disease), and H-shaped vertebrae (sickle cell disease or Gaucher's disease) (Figs. 4A, 4B, 5, 6, 7, 8). Obviously not every deformed vertebra is a vertebral fracture caused by osteoporosis.

Figure 2a.

Pitfalls in diagnosing vertebral fractures. In all examples, note presence of endplate deformities, lack of parallelism of endplates, or altered appearance compared with neighboring vertebrae. Lateral radiograph of lumbar spine shows mild wedge fracture (grade 1) of L3 vertebra.

Figure 2b.

Pitfalls in diagnosing vertebral fractures. In all examples, note presence of endplate deformities, lack of parallelism of endplates, or altered appearance compared with neighboring vertebrae. Lateral radiograph of lumbar spine shows moderate wedge fracture (grade 2) of L3 vertebra and moderate crush fracture (grade 2) of L2 vertebra.

Figure 2c.

Pitfalls in diagnosing vertebral fractures. In all examples, note presence of endplate deformities, lack of parallelism of endplates, or altered appearance compared with neighboring vertebrae. Lateral radiograph of thoracic spine shows severe wedge fracture (grade 3) of T7 vertebra.

Figure 3a.

Pitfalls in diagnosing vertebral fractures. Oblique radiograph of thoracic spine shows apparent wedge fracture.

Figure 3b.

Pitfalls in diagnosing vertebral fractures. Lateral radiograph shows normal vertebral shape.

Figure 4a.

Abnormalities in vertebral shape mimicking fracture. Lateral radiograph of lumbar spine shows deformity of inferior endplates that may mimic vertebral fracture.

Figure 4b.

Abnormalities in vertebral shape mimicking fracture. Frontal radiograph in same individual shows cupid's bow deformity, a developmental variant.

Figure 5.

Abnormalities in vertebral shape mimicking fracture. Lateral radiograph of lumbar spine shows limbus L4 vertebra, a developmental variant.

Figure 6.

Abnormalities in vertebral shape mimicking fracture. Lateral radiograph of thoracic spine shows H-shaped vertebrae in patient with sickle cell disease.

Figure 7.

Abnormalities in vertebral shape mimicking fracture. Lateral radiograph of lumbar spine shows Schmorl nodes at inferior endplates of L2 and L3 vertebrae.

Figure 8.

Abnormalities in vertebral shape mimicking fracture. Lateral radiograph of thoracic spine shows endplate irregularity and vertebral wedging characteristic of Scheuermann's disease.

What is the age of the fracture?—This question is particularly relevant in deciding whether a patient's current symptoms are due to that fracture. Unfortunately, on conventional radiographs, it is often difficult to determine the age of the fracture unless prior radiographs are available. When there is cortical disruption or impaction of the trabeculae, the diagnosis of acute fracture is obvious (Fig. 9A). When cortical disruption is not seen and the vertebra appears similar in density to the adjacent vertebrae, the diagnosis of an old fracture is equally apparent (Fig. 9B). However, in many instances, neither criterion is met and additional imaging studies may be useful. Lack of edema on MRI (Fig. 10A, 10B) or lack of radiopharmaceutical uptake on a bone scan (Fig. 11A, 11B) indicates an old fracture. However, even with advanced imaging, it may be difficult to accurately determine the age of a vertebral fracture (Fig. 12A, 12B). Note that even old vertebral fractures are important to mention because they increase the risk of subsequent fractures.

Figure 9a.

Differentiating acute and old fractures. Lateral radiograph of lumbar spine shows acute vertebral fracture. Note impaction of trabeculae.

Figure 9b.

Differentiating acute and old fractures. Lateral radiograph of lumbar spine shows old vertebral fracture. Note that fractured vertebra appears similar in density to adjacent nonfractured vertebra.

Figure 10a.

Lack of edema on MR images indicating old fracture. A Sagittal T1-weighted (A) and T2-weighted fat-suppressed (B) MR images show old L1, L2, and L3 vertebral wedge fractures. Note isointensity of fractured vertebrae compared with nonfractured L4 vertebra.

Figure 10b.

Lack of edema on MR images indicating old fracture. B Sagittal T1-weighted (A) and T2-weighted fat-suppressed (B) MR images show old L1, L2, and L3 vertebral wedge fractures. Note isointensity of fractured vertebrae compared with nonfractured L4 vertebra.

Figure 11a.

Lack of radiopharmaceutical uptake on bone scan idicating old fracture. Radionuclide bone scan shows no increase in uptake in lumbar spine.

Figure 11b.

Lack of radiopharmaceutical uptake on bone scan idicating old fracture. Lateral radiograph shows old mild biconcave fracture of L2.

Figure 12a.

Bone scanning for determining age of fracture. Radionuclide bone scan shows uptake in L2 vertebra that may indicate acute or subacute fracture.

Figure 12b.

Bone scanning for determining age of fracture. Lateral radiograph shows severe crush fracture of L2.

Can it be a pathologic fracture?—Critical to the evaluation of vertebral fractures on imaging studies is the fact that not all vertebral fractures are due to osteoporosis. In particular, antecedent trauma, infection, and tumor must be excluded. In many cases, MRI is useful for differentiating osteoporotic fractures from pathologic fractures by showing contrast enhancement of bone marrow and adjacent soft tissues in pathologic fractures. However, early after fracture, enhancement may be seen even in the absence of tumor (Fig. 13A, 13B).

Figure 13a.

MRI for determining age of fracture. MR images show acute wedge fractures of T12 and L1 and old wedge fracture of L2. T1-weighted image shows that acutely fractured T12 and L1 vertebrae have lower signal intensity than chronically fractured L2 vertebra.

Figure 13b.

MRI for determining age of fracture. MR images show acute wedge fractures of T12 and L1 and old wedge fracture of L2. T1-weighted fat-suppressed image obtained after administration of contrast agent shows enhancement in T12 and L1 vertebrae but no enhancement of L2 vertebra.

Standardized Reporting

After the fracture is detected (and traumatic and pathologic fractures have been excluded), it should be classified as wedge, biconcave, or crush (Figs. 1 and 2A, 2B, 2C). All visualized thoracic and lumbar vertebrae that are fractured should then be graded on the basis of the percentage of reduction in anterior height, middle height, or posterior height (Figs. 1 and 2A, 2B, 2C). This approach to reporting vertebral fracture assessment is based on one that has been widely used in clinical research, the semiquantitative method of Genant et al..[60]

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