Summary

Magnetic resonance imaging (MRI) and computed tomography (CT) are not always conclusive for the detection of cerebral venous sinus thrombosis (CVST). 99mTc-HMPAO-labeled platelets may be useful in cases with high clinical suspicion. 99mTc-HMPAO-labeled platelets may be useful in cases with high clinical suspicion. Three patients with headaches with or without intraparenchymal hemorrhage that were highly suspected to have CVST, despite inconclusive anatomical imaging, were selected for inclusion in the study. Platelets were extracted by two rounds of centrifugation from 49 ml of the patient’s whole blood.  The platelets were labeled with 99mTc-HMPAO and any unbound 99mTc was removed by centrifugation. The re-suspension of 99mTc-HMPAO-labeled platelets in cell-free plasma was reinjected into the patients. After 2 h, planar and single photon emission computed tomography (SPECT) images of the head were obtained. Extensive clots were detected in all three patients, illustrated in the planar image and even clearer in the SPECT images. We propose that 99mTc-HMPAO-labeled platelet scan is a favorable imaging method for patients suspected to have CVST with inconclusive CT and MRI results.

Fig. 1 Schematic overview of the study procedure including the labeling and imaging procedures

Results from AnyScan® DUO SPECT

The anterior, posterior, and bilateral planar views were acquired with the following specifications: 200 k-count, 128×128 matrix, and overall imaging time of 11 min for the two patients injected with lower activities. Subsequently, single photon emission computed tomography (SPECT) imaging was conducted in 64 views, 128×128 matrix size, and a projection time of 25 s. A dual head gamma camera was employed (AnyScan® DUO SPECT, Mediso, Budapest, Hungary).

In all three patients, the images were diagnostic. The SPECT images provided perfect delineation of the cerebral sinuses, and the clot was localized as a line of increased uptake in the sagittal and transverse sinuses as depicted in Fig.2. The uptake in the brain and skull was very low, and the clot-to-background ratio was 2.02, 1.47, and 1.54 in the posterior planar images, in patients one–three, respectively.

Fig. 2 Image of cranial sinus thrombosis in two women with intraparenchymal hemorrhage aged 49 and 31  years (panel a, b) and a man with a retractable headache aged 29 years (c) in transverse, sagittal, and frontal SPECT images 2  h after injection of self-donated 99mTc-HMPAO-labeled platelets. Arrows indicate thrombosis in the sagittal and transverse sinuses.

Conclusion

We believe that 99mTc-HMPAO-labeled platelets can be efficiently used when there is high clinical suspicion for cerebral sinus thrombosis, but the anatomical imaging is negative or ambiguous. We suggest that the prevalence of thrombotic events in the cerebral sinuses of patients with suspicious intracranial hemorrhage, as well as certain other pathologies including PTC, be further assessed using the labeled platelet scan. The scan may be tested for other thrombotic conditions including concealed thrombosis or undiagnosed thrombosis in the extremities or gastrointestinal tract when other imaging techniques are not conclusive.

Full article:springer.com