NUCLEAR TRACERS used in imaging prosthetic joints The tracers discussed in this article are: Tc-MDP: bone scintigraphy Tc-sulesomab (trade name LeukoScan): in vivo labelled Fab fragment of IgG1. While this also binds to neutrophils (5%) and therefore should mimic WBC labelled scans it has a non-specific accumulation at infected sites. 35% of activity at 24hrs is […]
Perfusion Scintigraphy versus 256-slice CT Angiography in Pregnant Patients Suspected of Pulmonary Embolism: Comparison of Radiation Risks
Perisinakis K, Seimenis I, Tzedakis A, Damilakis J J Nucl Med. 2014;55:1273-1280 Summary The goal of this anthropomorphic phantom-based simulation investigation was to compare the dose exposure estimates of state-of-the-art 256-slice CT pulmonary angiography (CTPA) with lung perfusion scintigraphy (LPS) in pregnant patients with suspected pulmonary embolism (PE) at different body sizes and gestation times (the end of […]
Hyperparathyroidism is most commonly due to adenomas or carcinomas. These can frequently be detected with dual phase Sestamibi scans. The sensitivity for detection is poor with planar and SPECT imaging (60-80%) but with the advent of SPECT-CT much higher sensitivities have been achieved (>85%). Multi-glandular disease is uncommon but paradoxically more difficult to detect with all modalities. Now with […]
Lung scan renaissance
Lung scans fell out of favour with the advent of multislice CT pulmonary angiography (CTPA) which offered a great improvement on the accuracy of lung scans shown by the PIOPED study done in the 1980’s. There is no doubt that CTPA is a readily available test for diagnosing pulmonary embolism. Nuclear technology has also moved on since the PIOPED study and more recent studies from various centres tend to suggest that there is very little difference in accuracy between the two modalities. In practice it is the appropriate use and application of the test that is more important than whether it is CTPA or V/Q lung scanning. The PIOPED II STUDY (New Engl J Med 2006,354:2317) showed the overall sensitivity of CTPA for the diagnosis of pulmonary embolism was 83% and the specificity was 96%. However, these data excluded CT studies that were technically inadequate or un-interpretable . When all the studies are included the sensitivity and specificity fall to 78% and 90% respectively. The positive predictive value was 86% and the negative predictive value was 95%. Most notably the positive predictive value was only 58% when the clinical probability was low. Therefore additional testing is necessary when clinical probability is inconsistent with the scan results.
Wang, Feng MD et al in Clinical Nuclear Medicine July 2009 (Volume 34 – Issue 7 – pp 424-427) concluded V/Q lung scan, perfusion scan combined with CR and CTPA all show high efficacy in diagnosing pulmonary embolism.
In a head to head comparison (all patients had both tests) of CTPA and SPECT-CT lung scans Gutte et al (V/Q SPECT AND LOW-DOSE CT VS MDCT IN PE. J Nucl Med 2009; 50:1987–1992) found SPECT-CT lung scans had a sensitivity of 97% and speciﬁcity of 100%. CTPA alone had a sensitivity of 68% and a speciﬁcity of 100%.
In a very recent study done at the Charles Gairdner Hospital Perth (Ling et al. Internal medicine Journal 2012;42:1257-1260) they demonstrated that the addition of low dose CT increases the diagnostic yield by providing alternative diagnoses and contributed to a final diagnosis in 36%. Their use of SPECT-CT for the diagnosis of pulmonary embolism had a sensitivity , specificity, and negative predictive values of 93%,100%, and 97% respectively.
Imaging Life is a magazine that promotes Molecular Imaging innovation amongst the huge worldwide user of Siemens nuclear equipment. In a special edition published in October 2012 the best SPECT-CT cases of 2012 are published. The cover image and one of the published cases originates from South East Nuclear Medicine in the Bega Valley Radiology […]
This middle aged female was referred with shortness of breath and a CXR reported as showing oligaema in the left upper zones that could indicate pulmonary embolism. The reconstructed planar lung scan showed a large matched defect corresponding to the left upper lobe. The SPECT-CT scan shows a large airspace is responsible for the abnormality -most […]