Spot Diagnosis

Giant cell tumors - dynamic curves

This patient has a typical giant cell tumor in the lower end of the radius on the plain radiograph (Fig. 1). The T1W coronal (Fig. 2) and T2W sagittal (Fig. 3) images, show typical features. On the contrast enhanced study, the lesion shows homogeneous enhancement (Fig. 4). The dynamic study however shows that the lesion is vascular with rapid uptake and wash-out, paralleling the artery (Fig. 5).

This is a curve usually seen with malignant tumors, but also seen in the vast majority of virgin and especially recurrent tumors.

Solitary pulmonary nodule lecture - slides 7-11

Giant cell tumor - distal radius

This 25-years old lady showed an expansile, osteolytic, trabeculated lesion involving the epiphysis and metaphysis of the distal end of the radius, with a narrow zone of transition, the lesion extending upto the articular surface (Figs. 1, 2). There appeared to an anterior cortical break (Fig. 2). The MRI showed the lesion to be isointense on the T1W images (Fig. 3) and mildly hyperintense on the T2W images (Fig. 4) with a focal area of necrosis (red arrowhead). The anterior cortical break (red arrow) and extra-osseous extension of the soft tissue, was well appreciated on the T2W sagittal image (Fig. 4).

Radiofrequency ablation (RFA) of a lung tumor

This is a 78-years old man, who had a 3.8cm sized mass in the left upper lobe (Fig. 1), which was proven to be a squamous cell carcinoma. There was marked surrounding emphysema and though the lesion was a T1 lesion, with no adenopathy or evidence of spread elsewhere on a PET study, he was not considered to be a candidate for surgery.

He was referred for a radiofrequency ablation (RFA). We had to make sure that we did not penetrate the emphysematous lung. Using the CT fluoroscopy function, it was possible to find an oblique route into the centre of the lesion (Figs. 2-4) and the tines of the electrode were then deployed (Figs. 5,6). A successful ablation was obtained with peri-lesional ground-glass attenuation (Fig. 7).

There was no evidence of a pneumothorax, but a plain-radiograph (FIg. 8) obtained 24 hours later showed fluid-fluid levels, presumably due to hemorrhage into the bullae. The patient however was comfortable and was discharged with due precautions.

Giant cell tumor

This is a 20-years old lady whose knee radiograph shows a well-defined, expansile osteolytic lesion involving the epiphysis and metaphysis of the lower end of the femur, extending upto the articular surface, with subtle trabeculations. The zone of transition is narrow, as would be expected in benign lesions.

This appearance is highly suggestive of a giant cell tumor.

Solitary pulmonary nodule lecture

1. Slides 1-3

2. Slides 4-6

Solitary pulmonary nodule lecture - Slides 1-3

Head injuries Lecture - Slides 51-55

Simple bone cyst with fracture

One of the complications of a simple bone cyst is fracture. The fracture is often transverse and one sign that is touted is the "fallen fragment sign", due to fragments of bone that are seen in the dependent portion on erect images (Fig. 1) - usually in the inferior aspect of the cyst. Even on MRI, which is performed in the supine position, bone fragments may be seen in the inferior aspect (Figs. 2, 3).

Oligemia

Pathology
Reduced blood flow to the lungs or a portion thereof

Radiology
General or local decrease in the apparent width of visible pulmonary vessels, suggesting less than normal blood flow; usually associated with increased lucency