Correct!
3. Unenhanced thoracic CT shows a small right pleural effusion without pleural thickening
Unenhanced thoracic CT shows a small right pleural effusion, with no clear evidence of pleural thickening. No gas is present in the right pleural space. The imaging features are non-specific. No definite evidence of peribronchial or mediastinal lymph node enlargement is present. No mediastinal gas foci are seen. No mediastinal mass is evident and no abnormality is present along the expected course of thoracic duct. A small hiatal hernia is present near the gastroesophageal junction, but the distal esophagus does not appear abnormally thickened when accounting for the relative under-distension of this structure.
Further clinical course: The patient underwent repeat chest radiography (Figure 9) for recurrent shortness of breath which showed re-accumulation of the right pleural fluid collection yet again.
Figure 9. Repeat frontal and lateral chest radiography several days following the unenhanced thoracic CT and nearly 35 days following the percutaneous microwave renal ablation procedure shows right pleural effusion re-accumulation. The right pleural effusion is again large.
The patient underwent several repeated thoracentesis over the ensuing month, always followed by rapid re-accumulation of a large, transudative, right pleural effusion. During this time frame, the patient also complained of abdominal bloating and was seen in the emergency room with dehydration and vomiting as well. His renal function had initially improved following the acute renal injury that occurred immediately after the percutaneous microwave ablation procedure, but then had worsened, with serum creatinine values remaining in the range of 3.5 – 4.5 mg/dL. Nephrology was consulted, and recommended a 99mTc-Mercaptoacetyltriglycine (MAG-3) renal scan (Figure 10) to assess for renal cortical infarction and viability of the right kidney.
Figure 10. 99mTc-Mercaptoacetyltriglycine (MAG-3) renal scan (posterior view; L = patient left, R= patient right).
Based on the findings at this examination, which of the following would be the most likely to establish the etiology for the patient’s right pleural effusion? (Click on the correct answer to proceed to the last of 7 panels)