Teaching cases

Teaching points:

• Therapy with 177Lutetium DOTA TATE can be useful for inoperable, metastatic GEP NETs.
• The rate of complete responses obtained by Kwekkeboom et al was only 2% in patients treated with 177Lu-DOTA TATE. They reported partial responses, minor responses, stable disease and progressive disease, respectively, in 26%, 19%, 35% and 15% of their patients.
• Treatment tolerance was good, significant reduction of symptoms was obtained and 2-yr survival rate was 76 ± 16%.
• Predictors of good response include: high uptake of lesions in somatostatin receptor scintigraphy and Karnofky’s performance status > 70%.
• Predictors of poor prognosis include: massive liver involvement, bone metastases and Karnofky’s index 70%.

Teaching points:

Causes of I-131 Unrelated to Thyroid Cancer

• Choroid plexus salivary glands, gastric mucosa, urinary tract; contamination by physiological sections.

• Ectopic gastric mucosa, other gastrointestinal abnormalities, urinary tract abnormalities, mammary abnormalities.
• Serous cavities and cysts.
• Inflammation and infection.
• Nonthyroidal neoplasms.
• Unexplained causes.
• Choroid plexus salivary glands, gastric mucosa, urinary tract; contamination by physiological sections.
• Ectopic gastric mucosa, other gastrointestinal abnormalities, urinary tract abnormalities, mammary abnormalities.
• Serous cavities and cysts.
• Inflammation and infection.
• Nonthyroidal neoplasms.
• Unexplained causes.

Case presentation:

• Female.
• 66 y.o.
• Recurrence of multinodular goiter (MNG) with intra-thoracic extension.
• History of mild, intermittent asthma and chronic hypertension treated with ACEI, with no cardiovascular symptoms.
• Her MNG was discovered 33 years before, treated with subtotal thyroidectomy, with benign changes on pathology examination.
• Seven years ago she had a thyroid scintigram performed using 99mTc pertechnetate which revealed significant residual thyroid tissue extending to mediastinum, with globally decreased uptake.
• She received no treatment at that time.
• Two years later she presented with large MNG recurrence, surgery being contraindicated because of anatomic considerations.
• Radiometabolic treatment was performed with 30 mCi of 131I in an attempt to reduce gland volume.

Teaching points:

• Recombinant human TSH (rhTSH)-stimulated iodine scintigraphy is an effective and safe alternative to thyroid hormone withdrawal,to be used during the post-surgical follow-up of papillary and follicular thyroid cancer.
• Its clinical efficiency for the detection of persistent and recurrent disease is similar to that of thyroid hormone withdrawal.
• As a novel clinical application, compressive goiters with benign changes and low uptake of 131I can be efficiently treated with the use of rhTSH.
• Recombinant human TSH-stimulated radioiodine therapy of nodular goiter allows major reduction of the radiation burden with retained efficacy.

Case presentation:

• Female.
• 52 y.o.
• Atypical dull aching left sided chest pains for 2 months, unrelated to effort, lasting hours, resolving spontaneously.
• No known CADRF, except mildly obese. - Clinical Examination of the cardiovascular system.Essentially normal.
• ECG normal.

Teaching points:

• 201Thallium, 99mTc sestamibi & tetrofosmin can all image breast tumours, with the added advantage of showing up axillary lymph node involvement if present.
• Tc tracers preferred because of image quality.
• 18F FDG can also used.

Case presentation:

• Male
• 62 y.o.
• Previous PTCS with stents (ADA, Cx) 8 months before. Exerptional dyspnea, no chest pain.
• No EKG changes. -Unable to exercise (knee prosthesis).
• Myocardial perfusion study (MPI) with dipyridamole.

Teaching points:

• Restenosis occurs in approximately one-third of patients undergoing PTCA, one-half of whom presents with symptoms.
• Functional imaging performed before 6 months of the procedure can yield false–positive results due to lack of recovery of coronary flow reserve .
• Non-invasive imaging is indicated after PTCA if atypical chest pain or other non-specific symptoms appear, or an exercise test is non-diagnostic / equivocal.
• Transient ischemic dilation (TID) is frequently related to balanced ischemia, which in turn is associated with multivessel disease.
• A drop in post-stress LVEF can reflect myocardial stunning and is related with increased risk of cardiac events.

Case presentation:

• Female.
• 49 y.o.
• Exertional shortness of breath, dull pressing chest discomforts for 6 months.
• 103kg weight. Obese.
• Hypertension.
• Type II DM.
• Hyperlipidemia.

Conclusions:

• Attenuation artifacts are the achilles heel of MPI. In most cases, there is a mild to moderate fixed perfusion defect in the anterior and antero-septal or antero-lateral walls depending on the position the breasts. In this case however, there was what appeared to be a reversible defect seen. This could be because the breast position may have changed between the 2 scans, or perhaps because a different position of camera head has been employed.
• Measures to reduce this type of artifact would be possibly breast strapping or using attenuation correction measures.

Case presentation:

• Female.
• 66 y.o.
• Previous MI.
• Dyspnea and non-specific chest discomfort.
• ECG: Q waves V3-V5.
• Echo: LVEF 48%, apical hypokinesia.
• Referred for MPS w/ pharmacologic stress.
• Dipyridamole + rest (2-day protocol), 99mTc-MIBI.
• Well tolerated, no symptoms, no ECG changes, BP 130/80 mmHg at rest, 120/75 mmHg during the test.

Teaching points:

• Myocardial necrosis with a paradoxical pattern (PP) is observed in a few proportion of patients with myocardial necrosis.
• Necrotic areas with PP have preserved myocardial flow, owing to either patency of the culprit artery, or the presence of collateral circulation to this territory when the artery is occluded.
• Patients exhibiting a PP on MPS with Tc-99m-labeled tracers have a better prognosis and better LV function than patients with a non-PP pattern in necrotic myocardial regions.
• PP can also be observed as an artefact in studies with low-count statistics, or if there is dominant attenuation during the stress portion.
• QC data should be always checked before interpreting MPS.

Case presentation:

• Male.
• 51 y.o.
• Hypertension and diabetes.
• Atypical sympotons (right are discomfort st stress).
• Echocardiography revealed LVH.
• Submitted for stress myocardial perfusion study (MPS).

Teaching points:

• Although TID is usually higher in patients with LAD ischemia or multivessel disease (MVD), it can also be found in patients with LVH or diabetes (like in this case).
• However, TID in the absence of evident perfusion abnormalities should always raise the question of balanced myocardial ischemia in the first place, which is more common in MVD.
• Exercise/rest MPS was performed with 99m-Tc-sestamibi.

Case presentation:

• Female.
• 61 y.o.
• 168cm Ht.
• 86kg Weight.
• CABG in1993 for TVD.
• Acute MI 8/12 before scan, PTCA/Stent.
• CAD risk: family history, hyperlipidemia, diabetes mellitus, hypertension.
• Study: Dipyridamole/ Thallium for recurrent chest pain.

Teaching points:

• In patients with previous CABG or PTCA, recurrent chest pain is an indication for myocardial perfusion imaging (MPI).
• The test can be useful to detect presence and severity of ischemia, as well as to identify the culprit vessel.
• Often, extension and severity of perfusion defects largely exceed abnormal ECG findings.

Case presentation:

• Male.
• 51 y.o.
• Tetralogy of Fallot (TF) - acyanotic form.
• Operated 16 years before
• Dyspnea.
• EKG: LV, RV hypertrophy, repolarization changes.
• Echo: LVH, RVH with preserved systolic function of both ventricles, mild pulmonary valve stenosis.
• MPS was indicated to rule out associated CAD.

Teaching points:

• TF is the most common cyanotic heart defect seen in children beyond infancy, the most common cyanotic congenital lesion likely to result in survival to adulthood, and currently the most common complex lesion to be encountered in adults after repair.
• TID can be the consequence of segmental or diffuse ischemia. Lack of proportionate microvascular growth in myocardial hypertrophy leaves the myocardium vulnerable to ischemia even in the absence of atherosclerotic plaques (diffuse vs. segmental ischemia).
• In addition to RV hypertrophy, LVH can develop due to LV overload in TF.
• Patients with acyanotic TF (or pink TF) may be asymptomatic or may show signs of heart failure from a large left-to-right shunt.
• Occasionally, an individual reaches adulthood without any surgical repair, although this is not common.
• Echocardiography is the modality of choice for the postoperative follow-up evaluation of patients with palliated or repaired TF.
• Residual abnormalities range from nearly normal heart to substantial RV dysfunction and residual RV outflow tract obstruction.
• MPS can be indicated in adult cases in which symptoms may resemble those from coronary artery disease.

Case presentation:

• Male.
• 67 y.o.
• Atypical angina (abdominal discomfort at stress).
• Normal exercise ECG.
• Submitted for stress myocardial perfusion study (MPS).
• Exercise/rest MPS was performed with 99mTc-sestamibi.

Teaching points:

• Abdominal pain / discomfort is not infrequent in patients with inferior wall ischemia.
• Sensitivity of exercise ECG is limited, especially in patients with one-vessel disease.
• Functional non-invasive stress imaging is indicated in patients with intermediate probability of CAD.
• MPS has the ability to identify disease in individual arteries, since the perfusion abnormalities usually correlate closely with coronary territories.

Case presentation:

• Female.
• 66 y.o.
• Hospital worker.
• Felt unwell for 3/52 before admission, with flu like symptoms.
• Hypertension.
• Hyperlipidemia.
• New onset of dull chest pain and breathlessness at rest (NYHA II-III).

Case presentation:

• Female.
• 16 y.o.
• Family history of sudden death (father).
• Pactices sports regularly.
• Presents with effort dyspnea.
• At physical examination, systolic murmur 3/6.
• Otherwise unremarkable.

Teaching points:

• HCM is the most frequent hereditary cardiovascular disease (0.2% global incidence).
• Autosomic dominance caused by mutations in at least 13 genes which codify the cardiac sarcomer proteins, being the most frequent.
• LVH associated with HCM may cause false positive results in ECG (ST depression), symptoms (chest pain) and MPS results (TID, drop in post-stress LVEF).

Case presentation:

• Female.
• 59 y.o.
• Atypical chest pain for the past 6 months.
• Total Cholesterol = 190; HDL = 40; LDL = 88 (on statins).
• Glucose: 0.93, HbA1C = 6.7 % (on insulin + metformin).

Teaching points:

• MPS investigates the pathophysiological consequences of luminal obstructive CAD, while CTA indicates the presence, extent and location of coronary atherosclerosis.
• For pratical purposes, CTA excludes CAD (high NPV).
• A negative CTA implies no need of MPS on follow-up.
• A positive CTA (if performed initially) implies the need for a MPS for short-term prognosis and eventual revascularization, because of low PPV.
• Combined anatomical and functional assessment may allow improved risk stratification.

Case presentation:

Patient 1

• Male.
• 45 y.o.
• Hyperlipidemia, Hypertension, Diabetes Mellitus.
• Presented with cardiogenic shock at the Emergency Department, treated with IABP and inotropic support initially.
• Intervention performed 3/7 after admission.
• Various cardiac imagings performed about 2 months later for progressive dyspnoea, NYHA IV.

Patient 2

• Female.
• 56 y.o.
• Presented at ER with a 4 day history of worsening dyspnoea at rest.
• No chest discomfort.
• Diabetes Mellitus.
• Hypertension.
• Hyperlipidemia.

Case presentation:

• Female.
• 63 y.o.
• Overweight, hypertension, dyslipemia, type II diabetes.
• Mild/moderate renal insufficiency.
• 2 acute episodes of pulmonary edema 8-3 months before.
• Presents with chest pain and weakness after mild exercise.
• The rest ECG was totally normal. -Medication: ARBS, diuretics, metformin, statins.

Teaching points:

• Myocardial viability assessment is indicated in patients with chronic LV dysfunction.
• In patients with LV dysfunction and myocardial viability, the mortality is significantly lower in those treated with revascularization than those treated medically.
• The extent of perfusion–metabolism mismatch is proportional to mortality rate in medically treated patients with chronic ischemic LV dysfunction.

Case presentation:

• Female.
• 51 y.o.
• Heavy family history of CAD, no other known risk factors.
• Episodes of atypical chest discomfort. - Positive exercise test.
• Submitted for CT angiography (CTA), reported as:Severe proximal LAD stenosis, no other lesions, Ca score >1000.

Teaching points:

• CTA is sensitive for detecting CAD, however the technique has limited value in predicting the degree of stenosis.
• Especially in the presence of arterial calcifications, it is sometimes difficult to assess the characteristics of a coronary lesion by CTA.
• Calcium score >300 is associated with poor accuracy of CTA results (incomplete evaluation of coronary tree).
• Myocardial perfusion has powerful prognostic value and is not affected by calcium score.

Case presentation:

• Male.
• 41 y.o.
• Overweight, hypertension, high cholesterol, stress.
• Typical chest pain.
• Echocardiogram: mild LVH, normal LV function.
• Exercise test: chest pain witn no ECG changes.
• Myocardial perfusion study (MPS) with exerecise.

Teaching points:

• In patients with no known coronary artery disease and at overall low-tointermediate risk, myocardial perfusion SPECT adds prognostic information and risk-stratifies patients beyond clinical and exercise data.
• Semiquantitative information obtained by gated SPECT provides important measurements of disease extent and severity.
• Perfusion scores are useful tools in clinical decision making and have been shown to have independent risk-stratification value.
• Post-ischemic stunning, as assessed by gated SPECT, is a marker for poor prognosis, particularly for ischemic cardiac events.
• Patients with high risk results should be managed aggressively - with revascularization procedures if possible.

Case presentation:

• Male.
• 73 y.o.
• Previous myocardial infarction, heart failure.
• Submitted for myocardial viability assessment.
• Myocardial perfusion study with 99mTc-sestamibi at rest and after nitrates.

Teaching points:

• Myocardial viability studies are important in patients with heart failure and coronary heart disease in order to identify patients in whom either CABG or PTCA could result in functional recovery.
• Hibernated (viable) myocardium is thought to be the result of chronic ischemia and is generally associated with improvement after revascularization.
• Myocardial viability can be assessed with SPECT perfusion studies (alone or with nitrate stimulation), PET, dobutamine echocardiography, or magnetic resonance imaging, with comparable diagnostic yield.

Case presentation: - Male. -38 y.o. - Exertiona chest pain -No CAD risk factors -Study: Exercise/ Tetrofosmin. - 75kg weight. - Ht 180 cm. Teaching points: -This is an intermediate probability pre-test case (young male with no risk factors and chest pain). -Myocardial perfusion imaging (MPI) is indicated since whatever the result is, it will have impact on patient management (Bayes’ theorem). - Sensitivity of MPI is much higher than exercise ECG for ischemia detection. -This result is high-risk for cardiac events, so the patient should be considered for urgent invasive management (angiography + PTCA).