Case Author(s): Anton J. Johnson, M.D., Ph.D. and Henry D. Royal, M.D. , 11/8/96 . Rating: #D2, #Q4

Diagnosis: Pulmonary Embolism

Brief history:

43 year old woman with a right lung transplant and worsening dyspnea.


Perfusion images (10/30/96).

View main image(vq) in a separate image viewer

View second image(vq). Ventilation images (10/30/96).

View third image(xr). Chest film (10/30/96).

View fourth image(an). Pulmonary angiogram (10/31/96).

Full history/Diagnosis is available below

Diagnosis: Pulmonary Embolism

Full history:

43 year old woman who, three years earlier, underwent right lung transplantation for primary pulmonary hypertension. She now presents with worsening dyspnea following a syncopal episode.


4.2 mCi Tc-99m MAA i.v. and 10.4 mCi Xe-133 gas by inhalation.


The initial perfusion images (10-30-96) demonstrate essentially no tracer activity in the right lower and right middle lobes as well as decreased perfusion to the apical and posterior segments of the right upper lobe. The ventilation portion of the study reveals a defect in the right lung base and there is opacification in the right base on the comparison chest radiograph (10-30-96).


The right lung perfusion defect is substantially larger than the corresponding ventilatory defect and radiographic opacity. In addition, there are no right upper lobe ventilation abnormalities to match the perfusion defects in the apical and posterior segments of the right upper lobe. Regardless of which interpretive scheme you use, these findings are consistent with a high likelihood ratio for pulmonary embolism.

A pulmonary angiogram was performed in order to determine whether or not the lesions would be amenable to embolectomy. The angiogram (10/31/96) shows a large round filling defect in the right main pulmonary artery with some contrast getting by to partially opacify vessels supplying the right upper lobe.


The patient underwent surgical embolectomy of a large thrombus in her right main pulmonary artery. The thrombus completely filled the arterial lumen except for a tiny channel that allowed some blood flow to the right upper lobe. A caliber change at the arterial anastomosis was felt to be the site of origin of the thrombus.

A follow-up (post-embolectomy) portable perfusion/aerosol study reveals marked improvement in the perfusion to the right lower lobe.

View followup image(vq). Follow-up portable perfusion/aerosol study (11/1/96).

ACR Codes and Keywords:

References and General Discussion of Ventilation Perfusion Scintigraphy (Anatomic field:Lung, Mediastinum, and Pleura, Category:Organ specific)

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Case number: vq020

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