Clinical outcomes of patients with suspected pulmonary embolism using 99Tcm-Technegas as a ventilatory agent for lung scanning

Diagnosis of pulmonary embolus using ventilation/perfusion lung scintigraphy: more than 0.5 segment of ventilation/perfusion mismatch is sufficient

“…Previously published data indicate that for Technegas lung scintigraphy approximately 10% of patients are classified as indeterminate (moderate-probability group) using the modified PIOPED diagnostic criterion. 14,27 When comparing the data from this study with the previously published university teaching hospital data, using the low-moderate probability group of this study and the moderate-probability group of the previous study as potentially indeterminate, the new criterion significantly reduces the indeterminate group (70/717 vs 20/924, z = 4.8, P < 0.003). Direct comparison should also take into account the different patient populations: a predominantly teaching hospital-based population (n = 717) compared with a predominantly private-hospital/outpatient patient population (n = 924).…”

“…This group consisted of 20 patients (2.2%), of whom only one had PE. Previously published data indicate that for Technegas lung scintigraphy approximately 10% of patients are classified as indeterminate (moderate‐probability group) using the modified PIOPED diagnostic criterion 14,27 . When comparing the data from this study with the previously published university teaching hospital data, using the low‐moderate probability group of this study and the moderate‐probability group of the previous study as potentially indeterminate, the new criterion significantly reduces the indeterminate group (70/717 vs 20/924, z = 4.8, P < 0.003).…”

“…[10][11][12][13] Tc-99m Technegas ventilation imaging is widely used throughout Europe and the Asia-Pacific regions and, when used with the modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) diagnostic criterion, has reduced the proportion of indeterminate studies. 14 Technegas is generated by rapid heating to 2550°C of Tc-99m pertechnetate solution within a graphite crucible in the presence of argon gas. 15 This generates Tc-99m-labelled carbon cluster particles with approximate mean particle size of 40 nm diameter that effectively transport to alveoli with normal respiratory effort.…”

V / Q-Szintigrafie zur Diagnostik der Lungenembolie – I. Durchführung und Beurteilung

“…Folgerichtig wird der frühere Referenzstatus der Pulmonalisangiografie beim Nachweis oder Ausschluss der Lungenembolie auch von radiologischer Seite nicht mehr aufrechterhalten [36]. Vergleichsstudien mit besserer Technik der Ventilationsszintigrafie (Technegas und 81m Kr) sowie mit adäquaten (wenn auch nicht optimalen) Vergleichstandards (Outcome und 4-Zeilen-Spiral-CT) sowie mit geringen Fallzahlen bescheinigen der planaren V / Q-Szintigrafie nicht nur ein hohe Sensitivität von 96 und 98 % (88 %) sondern gleichzeitig eine hohe Spezifität von 88 und 93 % (88 %) [4,7]. Vergleichsstudien, die auf einem klinischen Konsens beruhen, enthalten eine subjektive Komponente und bevorzugen die Multislice-Spiral-CT, da bei Kenntnis des szintigrafischen Befundes und der dort angegebenen Lokalisation des Embolus dieser im CT müheloser geortet werden kann.…”

Suspected acute pulmonary embolism: a practical approach. British Thoracic Society, Standards of Care Committee

“…The Pulmonary angiography should be considered in patients suspected of PE (a) if cardio-use of newer ventilation scanning agents allowing multiple views should reduce the pro-vascular collapse or hypotension is present, where it should be available urgently, and (b) portion of indeterminate scan reports. 78 The interpretation of lung scans may be where other investigations have failed to give a firm diagnosis. There are no absolute contra-difficult or misleading in several situations and alternative imaging investigations are often indications, although particular care should be exercised in patients with known sensitivity more rewarding:…”