**1. Introduction**

The pericardium is a muscular sac that covers the heart and cases its major blood vessels. It facilitates and greases the heart motions [1–3]. In embryonic stage, the internal layer of the pericardium forms the myocardium prior fused with the exterior layer of the fibrous layer [4–7]. Those layers are a few millimeters thick and they are separated from each other. The pericardium gets the blood from inner mammary arteries and its inversion from the phrenic nerve [8, 9]. The pericardium separates from the sternum, vertebral bodies, and diaphragm through many ligaments (**Figure 1**) [10].

The symptoms of myocarditis are common especially in middle-aged patients [11]. Those diseases can cause discomfort, chest pain, tiredness, breathlessness, and repeated visits to clinics. The coronary vessel disease is one of the causes of myocarditis and pericarditis [12–14]. The virus infection is the main cause of myocarditis. This infection is usually associated with serve viral infection. This infection may cause the injury to the myocardium tissues, and it is associated with the accumulation of fluid and local death of tissue, contingent on its nature and extent [15–18]. Fungal infections are infrequent and include aspergillosis, blastomycosis, and candidasis. The tissue can be recovered within days. In acute cases, complete functional tissues work within weeks [19]. Cardiomyopathy may cause the consequences of the chronic inflammatory process (**Figure 2**) [20, 21].

The causes of occurrence of acute myocarditis are idiopathic. Pericarditis is an inflammatory process that affects the pericardium tissues. The signs of pericarditis

**Figure 1.** *Shows the pericardium layers.*

**127**

than adults [44].

**pericarditis**

**3.1 Electrocardiography**

described in about 50% of cases.

findings are basic T-wave deviations (**Figure 3**) [45].

*Application of Medical Imaging in Diagnosis and Assessment of Myocarditis and Pericarditis*

of bypass graft surgery), and percutaneous heart examinations [34–36]. The bacterium spreads to the pericardium by blood or direct extension of the adjacent organs. Incidence of myocarditis has been stated after smallpox immunization. The neoplastic pericardium is a secondary cause of the pericarditis [37]. Patients with acute pericarditis have progressive disease and discomfort. This discomfort gets worse when the patient is lying supine. The pain in the area refers to the trapezius muscles and phrenic nerve. Fever might accompany the viral pericarditis [38–40]. Electrocardiogram (ECG) is the most frequent tool for acute pericarditis study. It shows a saddle shape that reflects subepicardium infection. In ECG graph, acute pericarditis shows no Q-wave and loss of R-wave. Imaging of the cardiac tissue has a limited role especially in uncomplicated acute pericarditis. Chest radiographs show the cardiomegaly and pericardial effusion (250 mL). Ultrasound imaging (M-mode and Doppler) is used to differentiate constrictive and restrictive cardiomyopathy. In the pediatric, a transesophageal probe is used to detect diastolic dysfunction. Cytological examinations of pericarditis include glucose, protein, cell count, bacteria and virus culture, and gram and Ziehl-Neelsen stain test. Myolemma and sarcolemma can detect immune-mediated pericarditis. In neoplastic conditions, the high level of the carcinoembryonic antigen is detected. Pericardial biopsy is

performed in the granulomatous or malignant suspicion [41–43].

**2. Clinical presentation of myocarditis and pericarditis**

The medical signs of acute pericarditis and myocarditis include malaise, rash, tiredness, arthralgias, and respiratory and digestive syndromes. The acute infection continues for few weeks. Patients might attend the clinic with chest discomfort, breathlessness, tiredness, and syncope. Cardiac beat disorders are common and include both atrial and ventricular with the possibility of atrioventricular blockage. The European study of the inflammatory disease showed that 72% had dyspnea and 32% chest discomfort. The medical signs in pediatric patients differ according to their age. Kids may have anxiety, tiredness, raised temperature, loss of appetite, increased breath rate, increased heartbeats, and blue skin due to lack of oxygen. Symptoms in toddlers might comprise of chest and abdominal discomfort, muscle pain, tiredness, cough, and fluid accumulation in tissues. The degree of symptoms is reliant on the age of the kid. Toddlers often have and might require progressive cardiovascular and respiratory care in the initial phases of their disease

**3. Medical imaging in diagnosis and assessment of myocarditis and** 

Echocardiography is beneficial for assessing cardiac tissue dimensions, wall width, systolic and diastolic, and intracavitary thrombi. This technique can assess cardiac failure. Myocarditis has no special radiographic features in this technique. Nevertheless, myocarditis is characterized by widened, enlarged, and ischemic cardiomyopathies. This technique is commonly used as a diagnostic tool. The accuracy of electrocardiography for pericarditis and myocarditis is about 47% because ECG

The classical ECG examination is comprised of four stages of changes and it is

*DOI: http://dx.doi.org/10.5772/intechopen.87218*

#### **Figure 2.** *Shows dilated heart.*

are rub, abnormal ECG findings and possible pericardial effusion, chest discomfort, and breathing difficulties. The pericardial rub is best heard at the end of the expiration phase with patient sloping frontward [22–24]. About 30% of patients with myocarditis might be accompanied with pericarditis. Pericarditis is difficult to detect. Some postmortem studies suggest that pericarditis is a subclinical type. Pericarditis accounts for 5% of patients who are attending to emergency rooms due to myocardial infraction and chest discomfort [25–29]. On laboratory results, pericarditis can be detected in a troponin I test. Nevertheless, the elevation of troponin (I) is not used as the adverse prognosis of the disease [30, 31]. Serology may approve the cause as infectious or autoimmune pericarditis. Acute pericarditis onsets with mild signs and symptoms and its treatment lasts for 6 weeks. The infection symptoms might reoccur within 4–6 weeks [32, 33]. The prevalence of pericarditis may include idiopathic, tuberculosis, viral (HIV infection) or systemic infection, cancer (breast, leukemia, lymphoma, and lung), radiation therapy (about 4% of mediastinal Hodgkin's disease), cardiac surgery (20% of the cases

*Application of Medical Imaging in Diagnosis and Assessment of Myocarditis and Pericarditis DOI: http://dx.doi.org/10.5772/intechopen.87218*

of bypass graft surgery), and percutaneous heart examinations [34–36]. The bacterium spreads to the pericardium by blood or direct extension of the adjacent organs. Incidence of myocarditis has been stated after smallpox immunization. The neoplastic pericardium is a secondary cause of the pericarditis [37]. Patients with acute pericarditis have progressive disease and discomfort. This discomfort gets worse when the patient is lying supine. The pain in the area refers to the trapezius muscles and phrenic nerve. Fever might accompany the viral pericarditis [38–40]. Electrocardiogram (ECG) is the most frequent tool for acute pericarditis study. It shows a saddle shape that reflects subepicardium infection. In ECG graph, acute pericarditis shows no Q-wave and loss of R-wave. Imaging of the cardiac tissue has a limited role especially in uncomplicated acute pericarditis. Chest radiographs show the cardiomegaly and pericardial effusion (250 mL). Ultrasound imaging (M-mode and Doppler) is used to differentiate constrictive and restrictive cardiomyopathy. In the pediatric, a transesophageal probe is used to detect diastolic dysfunction. Cytological examinations of pericarditis include glucose, protein, cell count, bacteria and virus culture, and gram and Ziehl-Neelsen stain test. Myolemma and sarcolemma can detect immune-mediated pericarditis. In neoplastic conditions, the high level of the carcinoembryonic antigen is detected. Pericardial biopsy is performed in the granulomatous or malignant suspicion [41–43].

### **2. Clinical presentation of myocarditis and pericarditis**

The medical signs of acute pericarditis and myocarditis include malaise, rash, tiredness, arthralgias, and respiratory and digestive syndromes. The acute infection continues for few weeks. Patients might attend the clinic with chest discomfort, breathlessness, tiredness, and syncope. Cardiac beat disorders are common and include both atrial and ventricular with the possibility of atrioventricular blockage. The European study of the inflammatory disease showed that 72% had dyspnea and 32% chest discomfort. The medical signs in pediatric patients differ according to their age. Kids may have anxiety, tiredness, raised temperature, loss of appetite, increased breath rate, increased heartbeats, and blue skin due to lack of oxygen. Symptoms in toddlers might comprise of chest and abdominal discomfort, muscle pain, tiredness, cough, and fluid accumulation in tissues. The degree of symptoms is reliant on the age of the kid. Toddlers often have and might require progressive cardiovascular and respiratory care in the initial phases of their disease than adults [44].
