Correct!
6. 1 and 2
Given the acute renal failure and dropping hemoglobin value (the latter raising the possibility of hemorrhage), abdominal imaging for this patient is indicated. Generally, abdominal imaging in the acute care setting may be performed using either CT of the abdomen (with or without intravenous contrast) or abdominal ultrasound. Abdominal ultrasound has the benefits of rapid performance, which can be accomplished portably at the bedside if needed, lack of use of ionizing radiation, and excellent depiction of hydronephrosis, which is a leading consideration in a patient with acute renal failure and suspected bleeding. CT of the abdomen is also quite capable of showing hydronephrosis in this setting and is probably a better choice than ultrasound for disclosing retroperitoneal hemorrhage, although ultrasound does remain an appropriate starting point in this context. Therefore, choice 6-both unenhanced CT of the abdomen and abdominal ultrasound- are appropriate choices for evaluating this patient. Abdominal MRI may be capable of showing hydronephrosis and retroperitoneal hemorrhage, and has the additional benefit of the lack of use of ionizing radiation, but MRI is more time consuming than either CT or ultrasound and is therefore not favored in the acute setting. Neither 18FDG-PET nor 68Ga-citrate scanning play a role in the evaluation of suspected acute urinary obstruction and / or post-procedural hemorrhage following a percutaneous ablation procedure and are not appropriate choices for this patient’s evaluation.
Clinical course: Both retroperitoneal ultrasound and unenhanced abdominal CT (Figure 5) were performed.
Figure 5. Unenhanced abdominal CT performed after development of acute renal failure following the percutaneous microwave ablation procedure shows cystic bilateral enlargement of both kidneys (shapes in D). Some of the cysts are hyperdense (arrow in C), consistent with hemorrhage or proteinaceous material. Mild perinephric fat stranding is present (arrowhead in F), which can be seen with retroperitoneal hemorrhage, but the mild nature of this finding is entirely consistent with the recent percutaneous microwave ablation procedure. Right pleural effusion (*) is again present. On the right is a movie of the unenhanced CT.
The CT examination showed a right pleural effusion, confirming the findings at recent chest radiography, and bilateral cystic renal enlargement, consistent with Von Hippel-Lindau syndrome. Mild perinephric fat stranding consistent with the recent percutaneous microwave ablation procedure was visible, but no findings suggesting either hydronephrosis or retroperitoneal hemorrhage were seen at either ultrasound or CT. The patient complained of persistent chest and abdominal pain, lethargy, intermittent fevers (patient indicated as high as 102°F), and general “unwellness.” At re-presentation 3 weeks later, the patient was afebrile with a normal white blood cell and platelet counts and normal electrolyte panels and liver function tests. The serum creatinine was 3.38 mg/dL and the hemoglobin and hematocrit had been stable at 10 mg/dL and 28%, respectively, over the previous few weeks. Repeat frontal chest radiography (Figure 6) was performed.
Figure 6. Frontal and lateral chest radiography performed just over 3 weeks following the right-sided percutaneous microwave ablation procedure.
Which of the following statements regarding the chest radiograph is most accurate? (Click on the correct answer to move to the fourth of seven panels)