Transcript Case 4
Incidental extra cardiac findings during Rubidium Cardiac PET/CT Shawgi M, James J, Arumugam P Nuclear Medicine Centre Central Manchester University Hospitals NHS Foundation Trust History • 74 year old male, 102 kg • Complaining of shortness of breath on exertion. Denied any chest pains. • Known dilated cardiomyopathy – to assess whether ischaemic in origin. • Multiple risk factors for CAD - hypertension, hyperlipidaemia, diabetes, family history, exsmoker and high BMI . Imaging protocol • Rest followed by stress imaging using 40 mCi (1480 MBq) Rubidium. • Images acquired on Siemens Biograph mCT scanner on 3 D mode. • Attenuation correction CT acquired with 120 Kv,11 eff mAs, Caredose on,3mm slices, pitch 1.5 and rotation 0.5s. Stress protocol • Adenosine infusion (140mcg/kg/min over 4.5 minutes) • No chest pain/dyspnoea • No ECG changes during or after the infusion. PET/CT MPS Images Stress Rest SA Stress Rest Stress VLA Rest Stress Rest HLA Image interpretation • Q – What are the salient findings on the perfusion study? • A– – The LV and RV cavities are dilated at peak stress and at rest. – Perfusion to the left ventricular myocardium is within normal limits at peak stress and at rest. Gated studies • Global moderate hypokinesis. • Ejection fraction estimated at 35%. What is the diagnosis? Lack of stress induced ischaemia or a significant infarct suggests a predominantly non-ischaemic aetiology to this patient’s LV dysfunction. Incidental finding • Review of the CT component revealed a 3.5cm soft tissue lesion in the left upper lobe, a 1 cm nodule in the left lower lobe and several enlarged mediastinal lymph nodes. 3.5cm soft tissue lesion 3.5cm soft tissue lesion 1 cm nodule mediastinal lymph nodes of varying sizes Follow up The patient went on to have a noncontrast CT scan (known renal impairment) and bronchoscopy which confirmed a primary lung carcinoma and associated mediastinal lymphadenopathy. Diagnostic CT Diagnostic CT- Lymph nodes Teaching Points • • When using CT attenuation correction in cardiac perfusion imaging, extra reporting time should be allowed for the review of CT data to look for incidental abnormalities in structures outside the heart. The true prevalence of significant extracardiac findings on cardiac CT is variable and is strongly influenced by patient selection (1). Onuma et al (2), found that using 16- or 64-slice multidetector CT scanners, extracardiac findings were found in 58% of patients, with 22.7% being clinically significant. 1) Douglas P, Cerqueria M, Rubin GD, et al. Extracardiac Findings: What Is a Cardiologist to Do? J. Am. Coll. Cardiol. Img. 2008;1;682-687 2) Onuma Y, Tanabe K, Nakazawa G, et al. Noncardiac findings in cardiac imaging with multidetector computed tomography. J Am Coll Cardiol 2006;48:402-406.