The Preliminary Application Of MR Diffusion Tensor Tractography In Estimating The State Of Cerebellar Peduncles In Cerebralinfarct

Objective1. To investigate the usefulness of diffusion tensor tractography (DTT) inpatients with CP lesions resulting from cerebral infarct.2. To estimate the relationship between the damage o f the CPs and the clinicalICARS score.MethodsWe recruited12patients with CP infarct and12age-and sex-matched controlsubjects. Diffusion tensor images (DTI) were acquired using a sensitivity-encodinghead coil at1.5T Philips MR. The superior cerebellar peduncle (SCP), the middlecerebellar peduncle (MCP), and the inferior cerebellar peduncle (ICP) were evaluatedusing Philips DTI software. Compared with the conventional MRI and the DTI image,we observed the difference of the cerebral infarction lesions. CPs lesion was gradedby reconstruction of DTT image according to the extent of the lesion．SCP, MCP, ICPcould be devided into3levels according to their degree of damage. Level1: CP wascomplete and damage, Level2: CP was complete but partially injured or pressed, Level3CP was injured completely or severely. The Posture and gait disturbances,Kinetic functions, Speech disorders and Oculomotor disorders were evaluatedaccording to International Co-operative Ataxia Rating Scale (ICARS)(WorldFederation of Neurology). Both the general conditions of patients and cerebralinfarction performance by the routine MRI were also observed. Thethree-dimensional reconstruction diagram of the control and patients’CPs by DTTwere also observed．Then we estimated their distribution and direction, and theconnection between their tract performance and the infarct. Finally we studied therelationship between ICARS subscores and the DTT (the injured degree of CP).ResultsThe contralateral CPs in the case group were basically consistent with thecontrol group in regard to anatomical structure and continuity. The ipsilateral CPs dueto cerebral infarction had different degrees of lesions with the loss of anatomicalcontinuity performance.Twenty-five of72total cerebellar peduncles in12patientswith CP infarct revealed the lesions in different extent (SCP:3, MCP:16, MCP:6).DTT showed7CPs were injured with level3damage(SCP:2, MCP:2, ICP:3). And20CPs with level2damage showed partially injured (SCP:1, MCP:14, ICP:3)orpressed slightly(SCP:1, ICP:1).45CPs (SCP:20, MCP:8, ICP:17)were undamaged.The patients with level3ICP damage suggested that dysarthria and oculomotordisorders score in the ICARS score were high(dysarthria score:≥6, oculomotordisorders score≥5). And the patients with level1ICP damage whose tract wasundamaged suggested dysarthria and oculomotor disorders scores in the total ICARSscore were very low, and fluency and clarity of speech in the patients were normalgenerally. The patients with level2ICP damage suggested that dysarthria andoculomotor disorders scores were between level1and level3.After the treatment, the pressure of the right SCP and ICP in patient7had recovered basically, and the rightMCP had increased, and the total ICARS score reduced obviously.ConclusionsCompared with the conventional MRI, We were able to determine the state ofthe CP by DTT, which could not be detected by conventional brain MRI, according tothe following aspect:(1) the presence of a CP lesion resulted from an infarct,(2) thecompleteness of a CP lesion,(3) in case of incomplete injury to the CP, the locationwhere integrity was preserved.(4) important value to detect the ischemic penumbrafor the infarct, and can guide clinical treatment. Therefore, we believe that DTT cangive us useful informations on the state of CPs which can not get from conventionalbrain MRI in patients with cerebral infarct.