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Pulmonary Cement Embolism Presenting With Dyspnea
Pulmonary Cement Embolism Presenting With Dyspnea Girish S. Shroff, MD, Ezinne Okwandu, MD, Chitra Viswanathan, MD, and Mylene T. Truong, MD
Case Report
A
70-year-old man with a history of metastatic prostate cancer and treated for vertebral compression fractures had shortness of breath at a urology appointment. He was immediately referred for chest radiography and pulmonary embolism protocol CT. CXR computed tomography (CT). Chest radiography showed several small, tubular, high-density opacities along the expected course of pulmonary arteries (Fig. 1). CT revealed cement deposits in segmental and subsegmental pulmonary arteries (Fig. 2). No thrombus was identified. He was treated with a standard course of Lovenox and then Coumadin. At 9 months prior, the patient presented to the emergency department following a motor vehicle accident. Workup at that time revealed compression fractures of the L1-L4 vertebral bodies. In the following months, these fractures were treated with minimally invasive vertebroplasty and kyphoplasty.
Diagnosis Pulmonary cement embolism.
Discussion Vertebral compression fractures are often caused by osteoporosis, tumor infiltration, myeloma, or hemangioma and result in severe pain, loss of vertebral body height, and kyphotic deformity. Percutaneous vertebroplasty (PV) and percutaneous kyphoplasty (PK) are vertebral augmentation procedures that serve as minimally invasive options to treat painful vertebral compression fractures. Application of these procedures has Department of Diagnostic Radiology, University of Texas MD Anderson Cancer Center, Houston, TX. Address reprint requests to Girish S. Shroff, MD, Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1478, Houston, TX 77030. E-mail: GShroff@ mdanderson.org
226
http://dx.doi.org/10.1053/j.ro.2015.01.005 0037-198X/& 2015 Elsevier Inc. All rights reserved.
expanded to include treatment of traumatic compression fractures. PV involves injection of bone cement (polymethyl methacrylate) into the spongy or cancellous bone of the vertebral body, where it solidifies within fracture lines and stabilizes the bone. PK involves a slight modification of the procedure where a balloon is inserted and inflated and deflated to create a cavity before the bone cement is injected. PK was introduced with the aim of improving some of the problems created by vertebroplasty such as restoring the vertebral body height as close as possible to the prefracture level. Additionally, because PK creates a cavity before injection of polymethyl methacrylate, the injection can be performed at a lower pressure, thereby limiting the risk of cement extravasation. Benefits of both the procedures include immediate pain relief, prevention of further vertebral body height loss, and correction of kyphotic deformity. Complications have increased as the number of PVs and PKs performed continue to rise. Complications include refracture of already treated vertebrae, fractures of adjacent vertebrae, and periprocedural complications such as fractures of the transverse process and pedicle and cement extravasation or embolism.1-4 Cement extravasation is usually asymptomatic and usually goes unnoticed unless incidentally detected during radiologic imaging. Extravasated cement may enter the neural foramen or spinal canal, resulting in radiculopathy or cord compression.4 Cement extravasation can also lead to cement embolism. Pulmonary cement embolism occurs when cement leaks into paravertebral veins and travels to the pulmonary arteries. Although most cement embolisms are asymptomatic, reported symptomatology includes dyspnea, tachypnea, tachycardia, chest pain, hemoptysis, and cardiac arrest.5-7 Cement embolism following PK or PV is estimated to occur in 4.6%-23% of cases.8-10 Cement emboli are easily seen on chest radiography because of their high density. The appearance of highdensity opacities in a tubular branching pattern corresponding to pulmonary arterial distribution is suggestive of the diagnosis.8 On CT, cement emboli appear as high-
Pulmonary cement embolism
227 calcified granuloma on CT. Cement emboli are intraluminal and may be branching, whereas granulomas are extraluminal and may be associated with lung distortion.10 On contrast-enhanced CT, cement emboli can be obscured by intraluminal contrast agents when using standard soft tissue windows. Using a slightly exaggerated window setting or bone windows allows for easier detection.9 The differential diagnosis of high attenuation emboli includes iodinated oil (used in hepatic transcatheter chemoembolization and lymphangiography) emboli, glue (used in the treatment of arteriovenous malformations and varices) emboli, and retained intravascular objects (such as fragments of catheters or vena cava filters or coils).11 Treatment strategies depend on the clinical scenario and vary from observation to anticoagulation to embolectomy. Anticoagulation therapy serves to reduce the risk of thrombus formation on the embolic cement material.
Figure 1 Chest radiograph showing small, tubular, high-density opacities (arrows) along the expected course of pulmonary arteries. In a patient with prior vertebroplasty or kyphoplasty, these findings are consistent with cement emboli.
Conclusion
density deposits within pulmonary arteries. They can be single or multiple. In a prospective study of patients who underwent noncontrast CT of the chest after PV, the number of cement emboli ranged from 1-20, and all were seen in the distal to third-order pulmonary arteries.10 When single, a cement embolus may be mistaken for a
Pulmonary cement embolism is a potential complication of PV or PK and occurs if cement leaks into paravertebral veins and travels to the pulmonary arterial system. Most cases are asymptomatic and discovered incidentally. Highdensity tubular or branching deposits within pulmonary arteries in patients who have undergone PV or PK suggest the diagnosis.
Figure 2 Axial CT images from pulmonary embolism protocol CT reveal cement emboli (arrows) in pulmonary artery branches. Using exaggerated window settings or bone windows allows for easier detection.
228
References 1. Boger A, Heini P, Windolf M, et al: Adjacent vertebral failure after vertebroplasty: A biomechanical study of low-modulus PMMA cement. Eur Spine J 16:2118-2125, 2007 2. Lin WC, Lee YC, Lee CH, et al: Refractures in cemented vertebrae after percutaneous vertebroplasty: A retrospective analysis. Eur Spine J 17:592-599, 2008 3. Syed MI, Patel NA, Jan S, et al: New symptomatic vertebral compression fractures within a year following vertebroplasty in osteoporotic women. Am J Neuroradiol 26:1601-1604, 2005 4. Mousavi P, Roth S, Finkelstein J, et al: Volumetric quantification of cement leakage following percutaneous vertebroplasty in metastatic and osteoporotic vertebrae. J Neurosurg 99:56-59, 2003 5. Jang JS, Lee SH, Jung SK: Pulmonary embolism of polymethylmethacrylate after percutaneous vertebroplasty: A report of three cases. Spine 27: E416-E418, 2002
G.S. Shroff et al 6. Padovani B, Kasriel O, Brunner P, et al: Pulmonary embolism caused by acrylic cement: A rare complication of percutaneous vertebroplasty. Am J Neuroradiol 20:375-377, 1999 7. Tozzi P, Abdelmoumene Y, Corno AF, et al: Management of pulmonary embolism during acrylic vertebroplasty. Ann Thorac Surg 74:1706-1708, 2002 8. Choe DH, Marom EM, Ahrar K, et al: Pulmonary embolism of polymethylmethacrylate during percutaneous vertebroplasty and kyphoplasty. Am J Roentgenol 183:1097-1102, 2004 9. Duran C, Sirvanci M, Aydogan M, et al: Pulmonary cement embolism: A complication of percutaneous vertebroplasty. Acta Radiol 48:854-859, 2007 10. Kim YJ, Lee JW, Park KW, et al: Pulmonary cement embolism after percutaneous vertebroplasty in osteoporotic vertebral compression fractures: Incidence, characteristics, and risk factors. Radiology 251:250-259, 2009 11. Bach AG, Restrepo CS, Abbas J, et al: Imaging of nonthrombotic pulmonary embolism: Biological materials, nonbiological materials, and foreign bodies. Eur J Radiol 82(3):e120-e141, 2013
Case Report
A
70-year-old man with a history of metastatic prostate cancer and treated for vertebral compression fractures had shortness of breath at a urology appointment. He was immediately referred for chest radiography and pulmonary embolism protocol CT. CXR computed tomography (CT). Chest radiography showed several small, tubular, high-density opacities along the expected course of pulmonary arteries (Fig. 1). CT revealed cement deposits in segmental and subsegmental pulmonary arteries (Fig. 2). No thrombus was identified. He was treated with a standard course of Lovenox and then Coumadin. At 9 months prior, the patient presented to the emergency department following a motor vehicle accident. Workup at that time revealed compression fractures of the L1-L4 vertebral bodies. In the following months, these fractures were treated with minimally invasive vertebroplasty and kyphoplasty.
Diagnosis Pulmonary cement embolism.
Discussion Vertebral compression fractures are often caused by osteoporosis, tumor infiltration, myeloma, or hemangioma and result in severe pain, loss of vertebral body height, and kyphotic deformity. Percutaneous vertebroplasty (PV) and percutaneous kyphoplasty (PK) are vertebral augmentation procedures that serve as minimally invasive options to treat painful vertebral compression fractures. Application of these procedures has Department of Diagnostic Radiology, University of Texas MD Anderson Cancer Center, Houston, TX. Address reprint requests to Girish S. Shroff, MD, Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1478, Houston, TX 77030. E-mail: GShroff@ mdanderson.org
226
http://dx.doi.org/10.1053/j.ro.2015.01.005 0037-198X/& 2015 Elsevier Inc. All rights reserved.
expanded to include treatment of traumatic compression fractures. PV involves injection of bone cement (polymethyl methacrylate) into the spongy or cancellous bone of the vertebral body, where it solidifies within fracture lines and stabilizes the bone. PK involves a slight modification of the procedure where a balloon is inserted and inflated and deflated to create a cavity before the bone cement is injected. PK was introduced with the aim of improving some of the problems created by vertebroplasty such as restoring the vertebral body height as close as possible to the prefracture level. Additionally, because PK creates a cavity before injection of polymethyl methacrylate, the injection can be performed at a lower pressure, thereby limiting the risk of cement extravasation. Benefits of both the procedures include immediate pain relief, prevention of further vertebral body height loss, and correction of kyphotic deformity. Complications have increased as the number of PVs and PKs performed continue to rise. Complications include refracture of already treated vertebrae, fractures of adjacent vertebrae, and periprocedural complications such as fractures of the transverse process and pedicle and cement extravasation or embolism.1-4 Cement extravasation is usually asymptomatic and usually goes unnoticed unless incidentally detected during radiologic imaging. Extravasated cement may enter the neural foramen or spinal canal, resulting in radiculopathy or cord compression.4 Cement extravasation can also lead to cement embolism. Pulmonary cement embolism occurs when cement leaks into paravertebral veins and travels to the pulmonary arteries. Although most cement embolisms are asymptomatic, reported symptomatology includes dyspnea, tachypnea, tachycardia, chest pain, hemoptysis, and cardiac arrest.5-7 Cement embolism following PK or PV is estimated to occur in 4.6%-23% of cases.8-10 Cement emboli are easily seen on chest radiography because of their high density. The appearance of highdensity opacities in a tubular branching pattern corresponding to pulmonary arterial distribution is suggestive of the diagnosis.8 On CT, cement emboli appear as high-
Pulmonary cement embolism
227 calcified granuloma on CT. Cement emboli are intraluminal and may be branching, whereas granulomas are extraluminal and may be associated with lung distortion.10 On contrast-enhanced CT, cement emboli can be obscured by intraluminal contrast agents when using standard soft tissue windows. Using a slightly exaggerated window setting or bone windows allows for easier detection.9 The differential diagnosis of high attenuation emboli includes iodinated oil (used in hepatic transcatheter chemoembolization and lymphangiography) emboli, glue (used in the treatment of arteriovenous malformations and varices) emboli, and retained intravascular objects (such as fragments of catheters or vena cava filters or coils).11 Treatment strategies depend on the clinical scenario and vary from observation to anticoagulation to embolectomy. Anticoagulation therapy serves to reduce the risk of thrombus formation on the embolic cement material.
Figure 1 Chest radiograph showing small, tubular, high-density opacities (arrows) along the expected course of pulmonary arteries. In a patient with prior vertebroplasty or kyphoplasty, these findings are consistent with cement emboli.
Conclusion
density deposits within pulmonary arteries. They can be single or multiple. In a prospective study of patients who underwent noncontrast CT of the chest after PV, the number of cement emboli ranged from 1-20, and all were seen in the distal to third-order pulmonary arteries.10 When single, a cement embolus may be mistaken for a
Pulmonary cement embolism is a potential complication of PV or PK and occurs if cement leaks into paravertebral veins and travels to the pulmonary arterial system. Most cases are asymptomatic and discovered incidentally. Highdensity tubular or branching deposits within pulmonary arteries in patients who have undergone PV or PK suggest the diagnosis.
Figure 2 Axial CT images from pulmonary embolism protocol CT reveal cement emboli (arrows) in pulmonary artery branches. Using exaggerated window settings or bone windows allows for easier detection.
228
References 1. Boger A, Heini P, Windolf M, et al: Adjacent vertebral failure after vertebroplasty: A biomechanical study of low-modulus PMMA cement. Eur Spine J 16:2118-2125, 2007 2. Lin WC, Lee YC, Lee CH, et al: Refractures in cemented vertebrae after percutaneous vertebroplasty: A retrospective analysis. Eur Spine J 17:592-599, 2008 3. Syed MI, Patel NA, Jan S, et al: New symptomatic vertebral compression fractures within a year following vertebroplasty in osteoporotic women. Am J Neuroradiol 26:1601-1604, 2005 4. Mousavi P, Roth S, Finkelstein J, et al: Volumetric quantification of cement leakage following percutaneous vertebroplasty in metastatic and osteoporotic vertebrae. J Neurosurg 99:56-59, 2003 5. Jang JS, Lee SH, Jung SK: Pulmonary embolism of polymethylmethacrylate after percutaneous vertebroplasty: A report of three cases. Spine 27: E416-E418, 2002
G.S. Shroff et al 6. Padovani B, Kasriel O, Brunner P, et al: Pulmonary embolism caused by acrylic cement: A rare complication of percutaneous vertebroplasty. Am J Neuroradiol 20:375-377, 1999 7. Tozzi P, Abdelmoumene Y, Corno AF, et al: Management of pulmonary embolism during acrylic vertebroplasty. Ann Thorac Surg 74:1706-1708, 2002 8. Choe DH, Marom EM, Ahrar K, et al: Pulmonary embolism of polymethylmethacrylate during percutaneous vertebroplasty and kyphoplasty. Am J Roentgenol 183:1097-1102, 2004 9. Duran C, Sirvanci M, Aydogan M, et al: Pulmonary cement embolism: A complication of percutaneous vertebroplasty. Acta Radiol 48:854-859, 2007 10. Kim YJ, Lee JW, Park KW, et al: Pulmonary cement embolism after percutaneous vertebroplasty in osteoporotic vertebral compression fractures: Incidence, characteristics, and risk factors. Radiology 251:250-259, 2009 11. Bach AG, Restrepo CS, Abbas J, et al: Imaging of nonthrombotic pulmonary embolism: Biological materials, nonbiological materials, and foreign bodies. Eur J Radiol 82(3):e120-e141, 2013