Anatomic variant

Review of postcontrast CTA source images might provide a good estimate of whole-brain perfusion." If time allows, MR or CT perfusion maps are obtained to characterize more accurately the ischemic penumbra." Careful but expedited preprocedural analysis of the CTA, done in parallel with transport of the patient to the treatment area, may be extremely helpful in establishing the presence of anatomic variants (e.g., bovine aortic arch) or pathological states (e.g., vessel origin or carotid bifurcation disease) prior to the catheterization procedure. 

The two main olfactory tracts [Fig. 2.19(a)] comprise an ipsilateral bundle — in the lateral olfactory tract (LOT) — and some contralateral fibres in the anterior olfactory habenular tract (AOHT). The input from the MOS and AOS shows no inter-familial differences in the final brain locations, apart from minor anatomical variants (Schmidt, 1990). 

Frequently encountered anatomical variants include (Thron 2001) ... 

Mishra R, Kaw R (2005) Eoix-Alajouanine syndr ome An uncommon cause of myelopadiy from an anatomic variant circuladon. Soudi Med 198 567-569. 

Figure 1.14 According to the anatomical variants of coronary circulation, there are areas of shared variable perfusion (A). The perfusion of these segments by the corresponding coronary arteries (B—D) can be seen in the bull s-eye images. For example, the apex (segment 17) is usually perfused by the LAD but sometimes by the RCA or even the LCX. Segments 3 and 9 are shared by LAD and RCA, and also small part of mid-low lateral wall is shared by LAD and LCX. Segments 4, 10 and 15 depend on the...

Regional HAI can be accomplished using a hepatic arterial port, a totally implantable pump, or a percutaneously placed catheter into the hepatic artery that is connected to an external pump. The volume of drug required to administer floxuridine can be contained within an implantable pump, whereas fluorouracil administration generally requires use of an external pump. Implanted infusion pumps are typically loaded with a 2-week volume of chemotherapy that is followed by an infusion of heparinized saline for 2 weeks. Candidates are selected carefully based on documentation of hepatic-only disease, good performance status, and no significant comorbidities or liver anatomic variants. 

Table 4.1. Relevant anatomic variants described by Michels...

Fig. 4.4. A rare anatomical variant consisting in the origin of the right hepatic artery (arrow) from the celiac trunk...

Additional clinically relevant anatomical variants are summarized in Table 4.2 (Figs. 4.4, 4.5). 

Unlike other loco-regional therapies, pre-procedure planning and meticulous mesenteric angiography are of paramount importance in order to determine the safest and most effective treatment strategy. Identifying anatomic variants, isolating the hepatic circulation and prophylactic embolization requires... 

The arteriograms of the celiac trunk and superior mesenteric artery should completely map the gastroduodenal blood supply. Anatomical variants should be searched for (esophageal, phrenic, hepatic arteries branching from the aorta, direct origin of the left gastric from the aorta, etc.). If all territories are visualized and no bleeding source... 

A personal case of anatomic variant was found during postpartum hemorrhage embolization in which the inferior mesenteric artery was the feeding vessel to the uterus (Fig. 9.4). 

Saraiya PV, Chang TC, Pelage JP, Spies JB (2002) Uterine artery replacement by the round ligament artery an anatomic variant discovered during uterine artery embolization for leiomyomata. J Vase Interv Radiol 13 939-941... 

Appropriate patient selection, careful catheterization and knowledge of different anatomic variants are important factors to minimize the failure after UFE. Systematic use of contrast-enhanced MRI is therefore essential, not only prior to the procedure, but also to monitor the perfusion of fibroids after... 

Differentiation from bicornuate uterus is based on the complete fundal unification however, a broad-based septate uterus is difficult to distinguish from an arcuate uterus. There is much controversy as to whether an arcuate uterus should be considered a real anomaly or an anatomic variant. Fact is that MRI may detect this abnormality but, typically, it is not clinically significant because arcuate uterus has no significant negative effects on pregnancy outcome. 

Numerous non-pathological appearances can simulate disease processes in the developing skeleton. These maybe anatomical variants, related to irregular, decreased or increased mineralisation during ossification, or artefactual. Only those that simulate the effects of trauma will be covered in this chapter, which is not intended to be exhaustive. Skeletal variations that are more commonly encountered in paediatric practice are included but the reader is directed to more comprehensive texts such as Theodore Keats Atlas (Keats and Anderson 2001), which this chapter is not designed to replace as a reference text. 

Normal Anatomical Variants and Other Mimics of Skeletal Trauma... 

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