Spot Diagnosis

Solitary pulmonary nodule lecture - slides 7-11

Solitary pulmonary nodule lecture - slides 4-6

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.

Solitary pulmonary nodule lecture

1. Slides 1-3

2. Slides 4-6

Solitary pulmonary nodule lecture - Slides 1-3

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

Air trapping

Plain Radiograph:
The retention of excess gas in all or part o fthe lung at any stage of expiration; to be used only when excess air is demonstrated by a dynamic study, such as inspiration/expiration films or fluoroscopy. Not to be used for overinflation

CT:
Decreased attenuation of pulmonary parenchyma, especially manifest as less than normal increase in attenuation during expiration. To be differentiated from decreased attenuation of hypoperfusion secondary to locally increased pulmonary arterial resistance.

The inspiratory and expiratory images shown below demonstrate air-trapping in the left lower lobe secondary to obliterative/constrictive bronchiolitis

Inflation

Inflation:
The state or process of being expanded or filled with gas; used specifically with reference to the expansion of the lungs with air; qualifiers are overinflation and underinflation

The radiographs show overinflation:
flattening of the diaphragms
increased supero-inferior length
increased retro-sternal air space

8mm lung subpleural lung nodule biopsy with CT fluoroscopy

This 41-years old man had come for a cardiac CT and an incident right lower lobe nodule was found. It showed subtle enhancement (Fig. 1), which made the lesion indeterminate and a biopsy was advised. Using the traditional technique (FIg. 2), the needle could be placed only along the side of the nodule. To get a more central location, CT fluoroscopy was used and under fluoroscopic, real-time guidance, the needle was placed accurately into the nodule (Figs. 3-5). Note the position of the interventional radiologist's fingers and hands on the anterior aspect.

The eventual diagnosis was of a probable old granuloma.

Emphysema

Pathology:
Permanently enlarged air spaces distal to the terminal bronchiole, accompanied by destroyed alveolar walls. Absence of "obvious fibrosis" historically has been regarded as an additional criterion, but the validity of that criterion has been called into question.

Radiology (CT):
Focal region or regions of low attenuation, usually without visible walls, resulting from actual or perceived enlarged air spaces and destroyed alveolar walls. May be associated with air trapping. (panacinar, distal acinar, centrilobular)