Relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism: assessment with breath-hold SPECT-CT pulmonary angiography fusion images.

Abstract

PURPOSE:

The relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism (PTE) was comprehensively assessed on deep-inspiratory breath-hold (DIBrH) perfusion SPECT-computed tomographic pulmonary angiography (CTPA) fusion images.

MATERIALS AND METHODS:

Subjects were 34 acute PTE patients, who had successfully performed DIBrH perfusion SPECT using a dual-headed SPECT and a respiratory tracking system. Automated DIBrH SPECT-CTPA fusion images were used to assess the relation between lung perfusion defects and intravascular clots detected by CTPA.

RESULTS:

DIBrH SPECT visualized 175 lobar/segmental or subsegmental defects in 34 patients, and CTPA visualized 61 intravascular clots at variable locations in 30 (88%) patients, but no clots in four (12%) patients. In 30 patients with clots, the fusion images confirmed that 69 (41%) perfusion defects (20 segmental, 45 subsegmental and 4 lobar defects) of total 166 defects were located in lung territories without clots, although the remaining 97 (58%) defects were located in lung territories with clots. Perfusion defect was absent in lung territories with clots (one lobar branch and three segmental branches) in four (12%) of these patients. In four patients without clots, nine perfusion defects including four segmental ones were present.

CONCLUSION:

Because of unexpected dissociation between intravascular clots and lung perfusion defects, the present fusion images will be a useful adjunct to CTPA in the diagnosis of acute PTE.

• Authors: Kazuyoshi Suga, Kawakami Yasuhiko, Hideyuki Iwanaga, Osamu Tokuda, Naofumi Matsunaga
• Journal: European journal of radiology (Eur J Radiol) Vol. 67 Issue 3 Pg. 472-80 (Sep 2008) ISSN: 0720-048X [Print] Ireland
• PMID: 17905552 (Publication Type: Journal Article)

Topics

• Adult
• Aged
• Angiography (methods)
• Female
• Humans
• Lung (diagnostic imaging)
• Male
• Middle Aged
• Pulmonary Artery (diagnostic imaging)
• Pulmonary Embolism (diagnosis)
• Respiratory Mechanics
• Subtraction Technique
• Tomography, Emission-Computed, Single-Photon (methods)
• Tomography, X-Ray Computed (methods)