Scintigraphic Diagnosis of Acute Pulmonary Embolism: From Basics to Best Practices

Early diagnosis for pulmonary embolism: A systematic review and meta-analysis

“…[ 47 ] Lung scintigraphy has stood the test of time as a reliable and validated examination for the determination of PE. [ 48 ] In the present study, most of the study subjects conformed to the standard study population and the same diagnostic thresholds were adopted to diagnose PE, effectively avoiding bias to a certain extent. Meta-analysis revealed that only Wells rules had a threshold effect for the diagnosis of PE, but there was significant heterogeneity in all 4 tests, so it was inferred that there were clinical, statistical and methodological differences between the D-dimer, Geneva rules and lung imaging for the diagnosis of PE.…”

Multimodality imaging of acute and chronic pulmonary thromboembolic disease

“…Indeed, these anomalies may also be caused by different conditions and not all cases of PE cause a V ʹ/ Q ʹ mismatch ( e.g. in the case of combined PE and PI, with decreased ventilation and perfusion); therefore, making the diagnosis a matter of probability of disease (although this approach could be considered obsolete with the new SPECT and SPECT-CT scanners) [ 23 , 33 , 34 ].…”

“…Regarding the interpretation of planar V ʹ/ Q ʹ scans, previously the suggested approach was to deem a scan as positive for PE if ≥2 segmental perfusion defects were detected in a patient with an appropriate pre-test probability while a normal scan excluded PE; in between these two diagnostic categories, a grey area is defined, including findings inconclusive or nondiagnostic for ruling out PE [ 34 ]. However, with V ʹ/ Q ʹ SPECT, which is the advised technique for diagnosing PE according to the European Association of Nuclear Medicine, a scan should be evaluated with a dichotomic approach (positive or negative for PE).…”

“…However, with V ʹ/ Q ʹ SPECT, which is the advised technique for diagnosing PE according to the European Association of Nuclear Medicine, a scan should be evaluated with a dichotomic approach (positive or negative for PE). Specifically, a case is defined as positive if at least a segmental or two subsegmental defects are detected, but the specific criteria to define the size of these mismatch areas are still debated [ 33 , 34 ]. Mismatch areas are usually detected as peripheral, wedge-shaped areas of reduced lung perfusion with a pleural basis, similarly to perfusion defects described on the DECT-derived iodine maps ( figure 5 ) [ 23 , 25 ].…”

“…However, scintigraphy is often not readily available in an emergency setting, the diagnostic criteria are still debated (as already stated above) and it does not provide alternative differential diagnoses [ 4 , 36 ]. According to the latest ERS/ESC guidelines, V ʹ/ Q ʹ scintigraphy could be safely used to rule out acute PE if the perfusion scan is negative and it could also be a valuable alternative to CTPA in selected cases, for example, patients with a history of anaphylaxis induced by iodinated CM administration [ 4 , 34 ]. In the setting of CTEPH, lung scintigraphy is the diagnostic test of choice for ruling out the disease; it can also provide additional information regarding the severity of disease, though in this case its role is still matter of discussion [ 30 ].…”