颅板下薄层出血的CT诊断与鉴别诊断

CT DIFFERENTIAL DIAGNOSIS OF THIN BLEEDING ADJACENT TO INNER PLATE OF SKULL

目的:分析急性外伤性颅板下薄层出血的CT表现,以便正确诊断和鉴别不同性质的出血。方法:回顾性分析36例头部外伤后颅板下薄层弧带(线)状出血病例的CT表现的异同。结果:硬膜下出血,表现为颅骨“假性增厚”,内缘模糊,多有一定的占位效应;蛛网膜下腔出血,出血内缘呈“锯齿”或“羽毛”状,外缘相对清晰,相邻脑沟密度增高或湮没,无占位效应,出血在短时间内淡化、消散;硬膜外出血呈内缘清晰的弧线状影,伴发同侧颅骨骨折、头皮血肿,无占位效应;硬膜下合并蛛网膜下腔出血,发生于对冲部位,占位效应较明显,内缘“锯齿”或“羽毛”状,短时间内复查,蛛网膜下腔出血多已消散;硬膜外合并同侧硬膜下出血,发生于伤侧,伴发骨折,呈相对较厚的“新月”形或“波浪”状,跨越颅缝。结论:颅板下薄层出血的内、外缘形态,有否占位效应,与外伤部位的相互关系是不同性质出血的鉴别诊断要点;CT复查,更容易将蛛网膜下腔出血与其它出血相鉴别;多窗技术和局部薄层扫描更能显示颅板下薄层出血及其形态学特点。

Objective： To assess the different CT manifestations of the thin bleeding which accumulated in the spaces next to the inner plate of the skull caused by acute head trauma, so that a correct diagnosis and differential diagnosis can be made. Methods： 36 patients with arc profile of thin bleeding caused by acute head trauma were reviewed retrospectively and the differences of their corresponding CT manifestations were discussed. Results： Cases of subdural hemorrhage（SDH） manifested false thickened skull, the inner margin of the skull were hazed, and most of them showed some mass effect. In the cases of Subarachnoid hemorrhage（SAH）, the profiles of the inner borders were in ＂saw - toothed＂ or ＂feather＂ shape and the outer margins were relatively clear, density of adjacent cortical sulci was increased or annihilated and none of them showed mass effect. CT countercheck within a short period showed that the blood was resolved spontaneously. Cases of extradural hemorrhage（EDH） showed that the profiles of the inner rim of the thin bleeding were clearly in arc shape and accompanied with local skull fracture or scalp hematoma, but no mass effect indication was shown. Cases of SDH coexisted with SAH, which were contrecoup injury, accompanied with great mass effect. The inner margins demonstrated the saw-toothed or feather shape. Countercheck in a short period showed that the blood in the subarachnoid cavity vanished. The case of EDH seen in conjunct with SDH, thickened crescentic or wave shape appeared, accompanied with local skull fracture but no mass effect and the hematoma was crossing the suturae cranii. Conclusion： The key points to the differential diagnosis between the different types of bleedings are as follows ： the shape of the border of the thin blood, the indications of mass effect and the relationship between the injury site and blood. Countercheck within a short period is especially useful to the differential diagnosis of SAH. Multi - windows setting technique and local thin section scan are helpful to show the blood and their imaging features.