Nuclear Imaging to Detect Diaphragmatic Perforation as a Rare Complication of Microwave Ablation

Abstract

Acquired diaphragmatic perforation leading to massive hepatic hydrothorax and respiratory failure is a rare complication of microwave ablation (MWA) of hepatocellular carcinoma (HCC). Imaging modalities to detect pleuroperitoneal communication remain poorly described. We report a nuclear imaging technique used to efficiently diagnose and locate diaphragmatic defects. A 57-year-old male with cirrhosis and HCC presented with respiratory distress after undergoing MWA of a HCC lesion. He was admitted to the intensive care unit for noninvasive positive pressure ventilator support. Chest radiography revealed a new large right pleural effusion. Large-volume thoracentesis was consistent with hepatic hydrothorax. The fluid reaccumulated within 24 hours; therefore an acquired diaphragmatic perforation induced by the ablation procedure was suspected. To investigate, 99mTechnetium-labeled albumin was injected into the peritoneal cavity. The tracer accumulated in the right hemi thorax almost immediately. The patient then underwent transjugular intrahepatic portosystemic shunting in efforts to relieve portal hypertension and decrease ascites volume. Unfortunately, the patient deteriorated and expired after few days. Although diaphragmatic defects develop in cirrhotic patients, such small fenestrations do not normally lead to rapid development of life-threatening pleural effusion. MWA procedures can cause large diaphragmatic defects. Immediate detection of this complication is essential for initiating early intervention.

Embryological, anatomical and clinical considerations on pleuroperitoneal communication

“…Thus, the right hemidiaphragm is in closer contact with the liver than the left hemidiaphragm does with the stomach or the spleen, respectively. Moreover, the right hemidiaphragm is mechanically less resistant than the left because it is less thick and muscular [ 3 , 14 ]. The porous diaphragm syndrome (gaps in the diaphragm that allow PPC commonly seen in the central tendon of the diaphragm) tends to appear on the right rather than the left side [ 15 ].…”

“…Additionally, congenital or acquired porous diaphragm syndrome may facilitate the movement of endometrium in the thorax [ 15 , 46 ]. The role of lymphatics should not be neglected as a possible pathway from the abdomen to the thorax, given that lymphatic stomata allow the entry of cells [ 14 , 47 ]. Thus, the theory of retrograde flow is a plausible explanation of the right predominance of endometrial implants in the diaphragm and the pleural cavities [ 15 , 46 ].…”

“…A rare complication of this technique is pleural effusion due to the development of an acquired PPC. Possible mechanisms include the thermal injury of the diaphragm and the penetration of the diaphragm by the needle during the procedure [ 56 , 57 ]. The predisposition for right pleural effusion is explained by the fact that the right hemidiaphragm is thinner and less muscular than the left hemidiaphragm [ 56 ].…”

“…Possible mechanisms include the thermal injury of the diaphragm and the penetration of the diaphragm by the needle during the procedure [ 56 , 57 ]. The predisposition for right pleural effusion is explained by the fact that the right hemidiaphragm is thinner and less muscular than the left hemidiaphragm [ 56 ]. Additionally, the right hemidiaphragm is more exposed than the left hemidiaphragm during the procedure.…”

“…Additionally, the right hemidiaphragm is more exposed than the left hemidiaphragm during the procedure. The already mentioned mechanisms of hepatic hydrothorax may contribute to this complication, but they fail to explain the acute onset of post-MWA pleural effusion [ 56 ]. Hence, the role of these mechanisms is questionable in post-MWA pleural effusion.…”