Emergency radiology 第1回  解答

急性膵炎診療ガイドライン 2010年
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Balthazal EJ.
Acute Pancreatitis: assessment of severity with clinical and CT evaluation.
Radiology 2002; 223:603-613

のp 608 より引用抜粋改変

CT Enhancement Values and Pitfalls
With helical or multidetector scanning with rapid acquisition of sequential images and collimation of less than 5 mm, images can be obtained in the early portal venous phase (60.70 seconds after intravenous administration of 150 mL of iodinated contrast material at a rate of 3 mL/sec). We still use a monophasic protocol, starting at the top of the diaphragm and covering the entire abdomen and pelvis. Since unenhanced images are not obtained, the detection of parenchymal injury is based solely on the degree and homogeneity of pancreatic enhancement. Basic pancreatic CT numbers of 40 .50 HU seen on unenhanced CT images are expected to increase to 100–150 HU throughout the entire normal gland during contrast material administration, depending on the size of the bolus, the speed of the injection, and the time of image acquisition (Fig 3). Lack of contrast enhancement or minimal contrast enhancement of less than 30 HU of a portion of the pancreas or of the entire pancreas indicates decreased blood perfusion (ischemia) and correlates with the development of necrosis (Figs 1, 4, 6). In this regard, however, several factors and potential pitfalls should be kept in mind.


この論文の中で壊死と浮腫をしっかり分けている。かなり具体的:p608-609 CT enhancement value
MDCT 5mm slice 厚、60-70s 3ml/s 150ml 総量
門脈相(60-70s 後)30HU未満では虚血、壊死を示唆する
しかし、いくつかの要因やピットフォールもある。例えば、元もと脂肪変性強い膵の場合、浮腫の強い場合、正常でも そう言う場合がある
膵壊死は、臨床症状発症から24-48時間後に生じる。もし、CTが12時間以内に撮影される とよくわからない。はっきりと壊死として濃染しない状態と成るには2-3日かかる。従って、72時間後 の方が壊死の正診率は高まる。48-72時間後がいい

Larvin M, Chalmers AG, McMahon MJ.
Dynamic contrast enhanced computed tomography: a precise technique for identifying and localising pancreatic necrosis.
BMJ 1990 Jun 2;300(6737):1425-8.

Lenhart DK, Balthazar EJ.
MDCT of acute mild (nonnecrotizing) pancreatitis: abdominal complications and fate of fluid collections.
AJR Am J Roentgenol. 2008 Mar;190(3):643-9.