Development of the aorta takes place during the third week of gestation. It is a complex process that can lead to a variety of congenital variants and pathological anomalies. In diagnostic and interventional radiology, knowledge of aortic abnormalities and variant branching sequence is crucially important. This article gives a systematic overview of anatomical variability of the aorta. KEYWORDS: Thoracic aorta, embryology, anatomical variantsObjectives: Upon completion of this article, the reader should (1) understand the development of the thoracic aorta and great vessels, and (2) understand the anatomical and pathological conditions that require consideration when treating diseases of the thoracic aorta. Development of the aorta takes place during the third week of gestation.1 It is a complex process associated with the formation of the endocardial tube (day 21), which lends itself to a variety of congenital variants. Each primitive aorta consists of a ventral and a dorsal segment that are continuous through the first aortic arch. The two ventral aortae fuse to form the aortic sac. The dorsal aortae fuse to form the midline descending aorta. Six paired aortic arches, the so-called branchial arch arteries, develop between the ventral and dorsal aortae. In addition, the dorsal aorta gives off several intersegmental arteries (Fig. 1).The vessels derived from each arch are as follows: The first pair contributes to formation of the maxillary and external carotid arteries. The second pair contributes to formation of the stapedial arteries. The third aortic arch constitutes the commencement of the internal carotid artery and is therefore named the carotid arch.Proximal segments of the third pair form the common carotid arteries. Together with segments of the dorsal aortae, the distal portions contribute to formation of the internal carotid arteries. The left arch of the fourth pair forms the segment of normal left aortic arch between the left common carotid and subclavian arteries. The right fourth arch forms the proximal right subclavian artery. The distal right subclavian artery is derived from a portion of the right dorsal aorta and the right seventh intersegmental artery. Rudimentary vessels that regress early develop out of the fifth pair. The left arch of the sixth pair contributes to the formation of the main and left pulmonary arteries and ductus arteriosus; this duct obliterates a few days after birth. The right sixth arch contributes to formation of the right pulmonary artery. 2With the caudad migration of the heart in the second fetal month, the seventh intersegmental arteries enlarge and migrate cephalad to form the distal subclavian

• MRI continues to yield further information concerning MS lesions. • SWI adds diagnostic information in patients with possible MS. • The "central vein sign" was predominantly seen in MS lesions. • The "central vein sign" helps discriminate between MS and non-MS lesions.

While correlating well with DSA above the knee, accuracy of DE-CTA MIPs appeared to be moderate in the calf and largely insufficient in calcified pedal arteries, especially in patients with critical limb ischaemia.

We report on a child with Chudley-McCullough syndrome and re-evaluate the spectrum of imaging findings (in 15 previously reported patients) which appear to be variable and, to some extent, ambiguous in the literature. Magnetic resonance imaging of the brain revealed asymmetric colpocephaly with agenesis of the splenium corporis callosi, ribbon-like subcortical gray matter heterotopia along the cingulate gyri, malrotation of both hippocampi, and dysplasia of the cerebellum. Macrocrania together with sensorineural hearing loss, colpocephaly, and posterior or complete agenesis of the corpus callosum can be considered the hallmarks of the autosomal recessive Chudley-McCullough syndrome. These may be variably associated with interhemispheric arachnoid cyst, cortical dysplasia, gray matter heterotopia, and cerebellar dysplasia. While early support with hearing aids may lead to improved language and cognitive outcome, shunting of ventricular dilatation is not indicated in the Chudley-McCullough syndrome.

Introducing gas to the circulation is a largely iatrogenic problem which can result in serious morbidity and even death. We report a case of CT-guided needle biopsy of a pulmonary lesion complicated by acute stroke. The English literature on cerebral air embolism is reviewed, including an update of current opinions on its pathomechanism, diagnostic findings, therapeutic strategies, and means of prevention.

BACKGROUND AND PURPOSE:Flat panel detector CT in the angiography suite may be valuable for the detection of intracranial hematomas; however, abnormal contrast enhancement frequently mimics hemorrhage. We aimed to assess the accuracy of flat panel detector CT in detecting/excluding intracranial bleeding after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption.

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Increased cerebellar volume was shown to be an additional feature in the early stage of fucosidosis. The combination with a confirmed tendency toward atrophy of the cerebellum during later course of the disease is probably unique in the context of metabolic disorders of the brain.