Multi-detector computed tomography in evaluating locally aggressive and malignant bone tumours

Abstract

Objective: To evaluate the ability of Multi-Detector Computed Tomography in preoperative evaluation of locally aggressive and malignant bone tumours in correlation with histopathological findings.

Materials and methods: Twenty patients suspected of malignant bone tumours on the basis of their clinical profile were selected. Following a plain radiograph evaluation, all of them were subjected to CT scan examination. Multi Planar Reconstruction (MPR) was done in sagittal and coronal planes and also three-dimensional Volume Rendering (VR) and Maximum Intensity Projection (MIP) images were obtained.

Results: Of the 20 patients, 18 underwent surgery, and their histopathological findings were compared and correlated with MDCT findings. MDCT was 92.8% sensitive and 100% specific in determining the vascularity of the tumour and also can detect displacement/ encasement/ involvement of adjacent vessels. It has a sensitivity and specificity of 100% in determining cortical break, calcification and periosteal reaction. However, it is less sensitive in detecting joint involvement. Post contrast enhancement gives details of the extent of the soft tissue component.

Conclusion: Although MRI is a preferred modality in preoperative evaluation of bone tumours, CT may be used an alternative in case of non-availability of MRI, which has faster acquisition time and better resolution. Using three dimensional MPR imaging, the location and extent of the tumour can be studied. It is also useful in determining cortical discontinuity, periosteal reaction, and calcification. By virtue of MIP and VR imaging, vascularity of the tumour and its relationship with the adjacent vasculature can be established. However, it is inferior to MRI in soft tissue characterization and has poor sensitivity in detecting marrow and joint involvement.

Keywords: Histopathology; MRI; Radiograph.

[Table/Fig-8a]:

Plain radiograph of a case of chondrosarcoma of right humerus showing destruction of the humeral head with pathological fracture at the neck and proximal shaft

[Table/Fig-8b]:

Coronal CT of the same case. (Arrow showing the cortical discontinuity)

[Table/Fig-9]:

Plain radiograph of a chondrosarcoma of left clavicle depicting chondroid matrix

[Table/Fig-10]:

Another case of chondrosarcoma involving the right proximal humerus, revealing “ring and arc” type of calcification (arrow) on axial CT

[Table/Fig-11a]:

Plain radiograph of a case of osteosarcoma of left proximal tibia showing osteoblastic matrix

[Table/Fig-11b]:

Coronal CT of the same case shows the matrix mineralization (arrow) along with adjacent soft tissue mass

[Table/Fig-12]:

Plain radiograph demonstrating sunburst-type periosteal reaction in a case of osteosarcoma of distal left femur.

[Table/Fig-13]:

Sagittal CT image of another case of osteochondroma involving the distal femur, shows hair-on-end type (arrow) of periosteal reaction

[Table/Fig-14a]:

Plain radiograph in a case of Ewings sarcoma of the left femur demonstrating permeative bone destruction with a large soft tissue mass

[Table/Fig-14b]:

Axial CT image at the level of the proximal femur of the same case, showing an enhancing soft tissue mass (arrow)

[Table/Fig-15a]:

Plain radiograph depicting a lytic expansile lesion involving the proximal right femur which turned out to be a chondrosarcoma

[Table/Fig-15b]:

VRT image of the same case showing the lesion being supplied by branches of the right profunda femoris artery (arrow)

[Table/Fig-16]:

MIP image of a case of osteosarcoma involving the distal femur, which illustrates posterior displacement of popliteal artery

[Table/Fig-17]:

VRT image of a fibular osteosarcoma that shows involvement of anterior tibial artery (arrow)