この症例では図４で，周囲の脂肪組織の濃度上昇を伴う，壁が強く造影された管腔臓器7が目立っており，それを正確に追跡して診断がつく．頭側では図３の8で盲端になり（SBは連続する小腸），尾側では図８の1から始まることを確認して急性虫垂炎の診断がついた． 図６の5から先端方向へ腫大するdistal appendicitis（下記文献）である．

参考症例（5mmスライス， distal appendicitis ）：11歳男児．24時間前に臍周囲痛が出現し，当日に下腹部痛となり発熱が加わった．体温：38.4℃，下腹部正中に圧痛と反跳痛を認める．
図８の1が虫垂起始部で，図６の糞石までは正常虫垂を示し，さらに図５の6と図４の7でも嵌頓した糞石があり，図３の8から数字順に，1cm以上に拡張した虫垂を示している．図１２と図１３で腹水（※）を認め，図５〜図８で虫垂左側に脂肪組織の濃度上昇を呈し，急性虫垂炎（distal appendicitis）である．病理：phlegmonous appendicitis．

文献考察： Distal appendicitisとは少なくとも3cm中枢側は正常の虫垂で、その末梢で腫大する虫垂炎で、頻度は7%（14/180例）
Rao PM, Rhea JT, Novelline RA.
Distal appendicitis: CT appearance and diagnosis.
Radiology. 1997 Sep;204(3):709-12.

PURPOSE: To determine the appearance of appendicitis in the distal part of the organ (distal appendicitis) on computed tomographic (CT) scans and to evaluate the accuracy of diagnosis based on CT findings. MATERIALS AND METHODS: CT scans and medical records in 180 consecutive patients with proved appendicitis were reviewed. Fourteen had distal appendicitis with at least a 3-cm length of normal proximal appendix. Appendiceal CT scans and initial reports were reviewed retrospectively. RESULTS: The proximal appendix was collapsed (n = 6) or was filled with contrast material (n = 6) or air (n = 2). Inflamed distal appendices averaged 13.2 mm in diameter and were associated with periappendiceal fat stranding (n = 14), adenopathy (n = 6), appendolith(s) (n = 4), or fluid (n = 2). Transition points consisted of a progressively narrowed appendiceal lumen and thickened wall (n = 5) or appendiceal diameter enlargement (n = 9). No cecal apical changes were seen. Scans in all 14 patients were prospectively interpreted as indicative of appendicitis, including 12 (86%) interpreted as indicative of distal appendicitis. CONCLUSION: CT findings are useful for the accurate diagnosis of distal appendicitis. Visualization of the proximal appendix alone is insufficient to exclude distal appendicitis. PMID: 9280247 [PubMed - indexed for MEDLINE]