Magnetic Resonance Imaging of Corpus Callosum: Normal Development and Anomalies

胼胝體之磁振造影：正常發育及異常

趙垂勳(Twei-Shiun Jaw) ； 劉金昌(Gin-Chung Liu) ； 鐘育志(Yuh-Jyh Jong)

《中華放射線醫學雜誌》 16卷2期 (1991/06) Pp. 137-150

摘要

胼胝體為聯結兩大腦半球之重要通道，在不同胚胎時期所發生的種種腦部傷害，可能造成不同的胼胝體異常，完全視傷害發生的時間而定。放射線學上，評估胼胝體的異常有助於瞭解其他相關腦部異常的性質及其可能發生的時期。而磁振造影為目前所有的影像診斷中，唯一可以直接清楚地看到，從前僅能藉由解剖方可見到之胼胝體結構者。本研究之目的在於利用磁振造影建立胼胝體之正常發展值，並探討各種胼胝體異常及相關腦部異常之磁振造影所見。
我們選擇腦部磁振造影所見正常之149位病童及20位成人，由T1為主的(T1-weighted)正中矢狀面影像，測定胼胝體在膝部(genu)、體部(body)及壓部(splenium)之厚度，胼胝體長度，以及腦前後徑。並計算後二者之比例。其結果如下：胼胝體在膝部及壓部之厚度，於前9個月有一成長高峰，此後成長趨緩，至7-9歲漸達成人值，其後則無明顯變化。體部厚度之成長曲線亦雷同，惟稍平坦。胼胝體之長度，雖於嬰兒期亦較快，一般而言，為穩定成長。而胼胝體與腦前後徑之比則隨年齡僅微微增加，介於0.38±0.03至0.46±0.02之間。在433例小兒腦部磁振造影檢查中，計發現有異常胼胝體者39例（佔9%），其中完全發育不全(complete agenesis)3例，部分發育不全(partial agenesis)4例，發育不良(hypoplasia)32例。又後者中屬全體性發育不良者21例（佔65.6%），局部性者11例（佔34.4%）。磁振造影發現合併有其他腦部異常者佔84.6%，其中最常見者為大腦萎縮。其主要臨床症狀，一般導因於合併之腦部異常，包括：抽搐、智能運動發育遲滯、巨頭或小頭。
磁振造影為胼胝體異常及其相關腦部異常之最佳診斷工具，尤其在有各年齡之正常值可供參考之情形下，更易於診斷。

關鍵字

胼胝體 ； 腦部異常 ； 腦部磁振造影

並列摘要

To evaluate normal development and anomalies of corpus callosum in childhood, magnetic resonance (MR) images of 149 children and 20 adults with normal findings were collected to measure the thickness of genu, body and splenium and the length of corpus callosum on the midsagittal T1-weighted images. The callosum/brain ratio was also calculated. The MR findings of 39 children with callosal anomalies were also reviewed. The development of callosal thickness behaved as a growth spur within the initial 9 months of life, followed by a gradual and steady increase until 7 to 9 years of age when the adult level achieved. The callosal length increased steadily from 43.2±6.3mm at the age of 0-3 months to 70.0±4.2mm in adult hood. The callosum/brain ratio increased very slowly with age from 0.38± 0.03 to 0.46 ±0.02. Callosal anomalies occurred in 9% of our pediatric cranial MR examinations. There were complete agenesis in 3 cases, partial agenesis in 4 cases and hypoplasia in 32 cases. Associated brain abnormalities occurred in 84.6% of these cases. Cerebral atrophy was the most frequent associated finding. With reference to the age-matched normal values, diagnosis of anomalies of corpus callosum and associated brain abnormalities can be well-established by MR.

並列關鍵字

Corpus callosum ； brain, abnormalities ； magnetic resonance imaging MRI, brain