池田 隆太, 塩屋 晋吾, 橋本 隆志, 福元 健, 大久保 友紀, 林 尚美, 佐々木 崇, 坂口 右己, 中村 克也, 重田 浩一朗

Ryuta IKEDA, Shingo SHIOYA, Takashi HASHIMOTO, Takeshi FUKUMOTO, Yuki OOKUBO, Naomi HAYASHI, Takashi SASAKI, Yuuki SAKAGUCHI, Katsuya NAKAMURA, Kouichirou SHIGETA

霧島市立医師会医療センター

Kirishima City Medical Center

キーワード : ultrasonography, profiling, anatomical study

目的：CT画像を基に解剖学的解析を行い，超音波検査（US）による左腎静脈を指標とした左副腎描出法の有用性につき検討した．検討項目：①左副腎結節疑いとしてCTを施行した50例を対象に，腹部大動脈（Ao），腹腔動脈（CA），上腸間膜動脈（SMA），左腎静脈（LRV）と左副腎の位置を解析し，新たな左副腎の描出法を作成した．②CT撮像歴がありUSを施行した正常例148例と同時期に経験した結節症例6例における3名の技師で左副腎の描出状況につき従来法（左肋間走査）と新たな描出法を比較検討した．結果：①左副腎は全てAo左側でLRVより頭側に位置しており，CA～SMAの間に位置する例が多かった（82％）.この結果，正中横走査にてLRVを描出し，その後CA～SMA起始部の左側領域を探索する方法（以下，新法）が最も有効であると考えた．②新法による左副腎の描出率は，正常例55％，結節症例100％であり，従来法（正常例9％，結節症例50％）と比べ有意に高い描出率を示した. 描出不能群におけるLRVの描出率は21％と低く，特にBMIの上昇がLRVの描出状況に影響することが示唆された．結語：左腎静脈を指標とした左副腎の描出法は，正常例および結節例の検出に有用と考える．

Purpose: To investigate the utility of ultrasonography (US) for delineating the left adrenal gland using the left renal vein (LRV) as a landmark, based on anatomical analysis of computed tomography (CT) images. Methods: (i) The position of the left adrenal gland was analyzed in relation to the abdominal aorta (Ao), celiac artery (CA), superior mesenteric artery (SMA), and LRV in 50 cases where CT was performed for suspected left adrenal nodules. Based on this analysis, a novel method for delineating the left adrenal gland was developed. (ii) Three technicians compared the delineation of the left adrenal gland using the conventional method (left intercostal scan) and the novel method in 148 normal cases with a history of CT imaging and six nodule cases encountered during the same period. Results: (i) All left adrenal glands were located on the left side of the Ao and cephalad to the LRV, with the majority (82%) positioned between the CA and SMA. Based on these findings, a transverse midline scan to delineate the LRV followed by a search of the region left of the CA-SMA origin (hereafter referred to as the “novel method”) was considered the most effective approach. (ii) The delineation rate of the left adrenal gland using the novel method was 55% in normal cases and 100% in cases with nodules, significantly higher than the conventional method (9% in normal cases and 50% in nodular cases). The delineation rate of the LRV in the non-visualization group was low (21%), suggesting that elevated BMI notably impacts the LRV delineation status. Conclusion: The delineation method using the LRV as a landmark for the left adrenal gland is considered useful for detecting both normal and nodular cases.