Kawasaki disease is an acute febrile illness associated with multiorgan vasculitis of unknown etiology that primarily affects infants and children. [1, 2, 3, 4] The disease probably has existed for a long time, but it was not recognized as a separate entity until Dr Tomisaku Kawasaki first described it in 1967.  Kawasaki disease was later reported in the English-language literature in 1974. 
See Kawasaki Disease: Do You Know the Signs?, a Critical Images slideshow, to help identify the specific criteria for diagnosis.
Kawasaki disease is a multiorgan disease. During the acute phase, children may develop aseptic meningitis, hyperemic tympanic membrane, or uveitis. Neurologic complications, which include facial nerve palsy, seizures, and ataxia cerebral infarctions, are rare. Other common features include diarrhea, vomiting, abdominal pain, and pneumonitis. Gallbladder hydrops (acute acalculous distention of the gallbladder; see image below) may occur in the first 2 weeks of illness, it may be the result of the extension of periportal inflammation to the cystic duct, and it is typically self-limited. Arthritis and arthralgia are common in the acute phase. Findings that include erythema and induration at the site of recent Bacille Calmette-Guérin vaccination, testicular swelling, and peripheral gangrene also have been reported in patients with this disease.
The ECG is usually normal.
Chest radiography is not routinely performed to evaluate for Kawasaki disease, and the results are often normal. 
If coronary aneurysm and calcification of the coronary artery aneurysm wall are present, they may be detected as cystic calcification in the region of the coronary vessels, overlying the heart shadow.
CT is not routinely performed for the evaluation of Kawasaki disease; however, CT is more sensitive than chest radiography in detecting coronary calcifications. Contrast-enhanced CT may demonstrate enhancement of the vessel walls in the coronaries, particularly in the acute phase. 
Although no published data describe the use of CT in detecting Kawasaki-related coronary aneurysms, recent advances in multihelical technologies, as well as electron-beam CT, may be useful in detecting and sizing coronary artery aneurysms. CT is also useful in evaluating the size of the gallbladder and in detecting gallstones.
Retropharyngeal lymphadenopathy and retropharyngeal edema have been found to be relatively common features of Kawasaki disease on CT. 
In selected high-risk patients with Kawasaki disease, coronary CT angiography may identify a subset of patients at increased risk for future coronary pathology who may benefit from medical therapy. 
Magnetic Resonance Imaging
MRI is not performed routinely to investigate Kawasaki disease; however, MRI may depict coronary aneurysms. [11, 12] MRI with gadopentetate dimeglumine can be use to noninvasively and simultaneously evaluate myocardial thinning and the presence of circulation. In addition, MRI is considered useful for the long-term follow-up of patients with Kawasaki disease.  Recent advances in cardiac MRI may enable the detection of early changes in Kawasaki disease. Acute-phase disease may be detected on MRI with or without Gd enhancement as an area of inflammation characterized by a high signal intensity on T2-weighted images; this area may be enhancing. [8, 14, 15]
Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.
When performed by skilled imagers, 2-dimensional echocardiography has 100% sensitivity and approximately 90% specificity for detecting aneurysms of the proximal coronary arteries. (See the image below.)
Intravenous immunoglobulin (IVIG)–resistant Kawasaki disease patients present with significantly greater diastolic dysfunction compared to IVIG responders. Tissue Doppler imaging (TDI) may be a useful tool to differentiate KD patients at higher risk of IVIG resistance. 
Angiography may be used to evaluate for coronary aneurysms (see the image below).  Although it is considered to be the criterion standard for evaluating coronary aneurysms, ultrasonography provides an alternative method of detecting coronary aneurysms, particularly proximal ones.