CT は全例で行われたが,造影 CT は 29 例に施行され た。41 例中,造影 CT が行われた 2 例を含む 12 例で特別 な異常所見は認められなかった。造影 CT で最も高頻度な 所見は両側性の多発性造影不良域(図 1a)であり,19 例に 認 め ら れ た( 全 体 の 4 6 . 3 % , 造 影 C T を 受 け た 症 例 の う ち 65.5 %)。造影されなかった 12 例のうち,2 例で両側のび まん性腎腫大(図 1b)が認められた。また,造影 CT が施行 された症例でも 1 例では,両側のびまん性腎腫大のみが異 常所見であった。造影 CT された 6 例で,内腔面の凹凸不 整を伴わないびまん性腎盂壁肥厚が認められた(図 1d)。こ の所見は,IgG4 関連疾患の全身精査中に偶然発見されるこ とが多かった。造影 CT が行われた残りの 1 例では,単発 性腎腫瘤(hypovascular)(図 1c)が認められた。
http://www.jsn.or.jp/jsn_new/iryou/free/kousei/pdf/53_8_IgG4...

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Note added at 2 hrs (2012-12-14 10:20:15 GMT)
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Compared with visceral parenchymal enhancement, the determination of an optimal injection duration is more complicated for arterial or CT angiographic enhancement. This is because the degree of contrast enhancement is directly affected by the contrast medium delivery rate (see the injection rate section). For single-detector CT angiography or slow scans, the injection duration is usually set to be the same as the scan duration (113). This rule of thumb, however, may not be practical at multidetector CT because of markedly reduced scan durations. Contrast medium injected with its duration matched to a short scan duration likely results in poor enhancement. One may be tempted to use a short, ultrafast injection to achieve a desired arterial enhancement level during image acquisition, particularly with ultrafast multidetector CT. This scheme does not work in practice because an injection rate higher than 8–10 mL/sec would not further elevate the magnitude of contrast enhancement (because of contrast medium dispersion and reflux from the right atrium, the pressure performance envelope of power injectors, and the risk of stressing the venous injection site at such high flow rates). Furthermore, the very short temporal window of diagnostically adequate enhancement resulting from a very short bolus makes precise scan timing highly challenging. Therefore, an injection with its duration less than 15 seconds is in general not recommended for diagnostic CT examinations in adults.
http://radiology.rsna.org/content/256/1/32.full

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Note added at 2 hrs (2012-12-14 10:24:46 GMT)
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むしろ、膵の造影不良域poorly perfused areaと表現すべきであろう。
http://www.snh.go.jp/Journal/SMCJ2011-1-2_8.pdf