肝臓と脾臓周囲に大量の腹水を認めるが，図７と図８の胃液より高濃度を呈し血液であろう．肝臓は萎縮性で肝硬変を疑う．図２〜図９，図１１〜図１７の△は脾臓実質よりdensityが高く脾臓外から連続するのでextravasationである．図４〜図７の↑は脾門部に位置し正常血管の可能性があり，図７〜図１１の▲は脾臓実質内にあり辺縁シャープな円形を示しているのでpseudoaneurysmと解釈するが，double phase造影CTであれば鑑別が容易になる．出血量を計算してみよう（参照症例）．7つの各部位で平均的な所を選び，図９の肝周囲に200，脾臓周囲に400，図１６でMorison窩に150，図１９で右傍結腸溝に200，左傍結腸溝に200，小腸間に200，図２０の骨盤腔内に500，合計1850mlとなる．2000ml以上の輸液に反応しないnon-responderであるため手術となり，肝硬変，活動性動脈性出血を伴う脾臓損傷を認め脾臓摘出術を施行したが，術中も低血圧が続き，出血傾向とacidosisが出現し出血量は5800mlに及んだ．術後も血圧が回復することがなく死亡した．反省点としては，non-responderは手術の適応であるが，ガーゼ充填術によるdamage control surgery（次回後述）を行い，血管造影・TAEを施行すべきであったと思われる．

参考症例（脾臓損傷 IIIb）：14歳男児．サッカーの試合中に他選手に左上腹部を膝で蹴られ，腹痛を訴え来院した．Vital signsは安定．左上腹部に圧痛，反跳痛と筋性防御を認めた．
図１と図２の▲は胃大網動静脈であろう．脾臓損傷があり，図２〜図５の△は“contrast blush”（造影剤の貯まり）であるが，活動性出血を意味するextravasation（造影剤の血管外漏出）か，extravasationを伴わない（現在は出血していない）仮性動脈瘤かの鑑別にはdouble phase造影CTが必要である．血管造影でextravasation（図Aと図B：↑）を認めスポンゼル細片で塞栓した．Hbは13.5g/dlから9.8g/dlに低下したが，輸血なしで順調に経過した．

文献考察：脾臓外傷のAAST分類ではextravasationや仮性動脈瘤の所見が考慮されていない．新分類は血管造影または手術を要する症例の選択により正確である（表１，２，３）．
AJR Am J Roentgenol. 2007 Dec;189(6):1421-7.
Optimization of selection for nonoperative management of blunt splenic injury: comparison of MDCT grading systems.
Marmery H, Shanmuganathan K, Alexander MT, Mirvis SE.

OBJECTIVE: The purpose of this study was to compare the usefulness of two CT grading systems of blunt splenic trauma in predicting which patients need surgery or angioembolization. MATERIALS AND METHODS: Four hundred patients in hemodynamically stable condition admitted with blunt splenic injury were included in the study. All patients underwent contrast-enhanced MDCT. Grade of splenic injury was prospectively assigned according to the American Association for the Surgery of Trauma (AAST) splenic injury scale. Patients were treated with surgical intervention, splenic arteriography with or without embolization, or observation alone. All MDCT images were retrospectively reviewed and regraded according to a novel grading system that specifically incorporates the findings of active bleeding or splenic vascular injury, including pseudoaneurysm and arteriovenous fistula. Receiver operating characteristics curves were generated with both grading systems for all splenic interventions, and statistical analyses were performed. RESULTS: The area under the ROC curves for the new splenic grading system for splenic arteriography, surgery, and both interventions exceeded 80%. The area under the curve for the new splenic grading system was greater than that for the AAST injury scale for all interventions. Differences were found to be statistically significant for splenic arteriography (p = 0.0036) and the combination of arteriography and surgery (p = 0.0006). CONCLUSION: The proposed CT grading system is better than the AAST system for predicting which patients with blunt splenic trauma need arteriography or splenic intervention.PMID: 18029880（full text）