BACKGROUNDIntraoperative ultrasound (IOUS) has been increasingly used as a guiding tool during neurosurgical procedures. In this study, we aimed to evaluate the potential application of intraoperative ultrasound assisted surgery in the resection of small, deep-seated, or ill-defined lesions.

METHODSEighty-six consecutive patients with small, deep-seated, or ill-defined intracerebral lesions were studied prospectively. An improved intraoperative imaging technique and surgical setup were practiced during the surgery. IOUS was performed in three orthogonal imaging planes (horizontal, coronal and sagittal).

RESULTSHistopathological diagnoses of these 86 cases included cavernomas, metastases, hemangioblastomas, gliomas, and radiation necrosis. Forty-seven of the 86 lesions (54.7%) were small and deep-seated, 34/86 (39.5%) were ill-defined, and 5/86 (5.8%) were small, deep-seated, and ill-defined. Sonograms in the horizontal plane were obtained in all 86 cases. Sonograms in the sagittal plane and in the coronal plane were obtained only in 52 cases and in 46 cases, respectively, due to technical limitation. In 13 cases, sonograms in all three orthogonal planes were available. All lesions were successfully identified and localized by IOUS. Total resection was performed in 67 lesions (77.9%) and partial resection was performed in 19 lesions (22.1%).

CONCLUSIONSWe propose IOUS to be performed in three orthogonal planes when surgery is planned for small, deep-seated, or ill-defined brain lesions. By applying this simple, improved technique, surgeons can perform resection of these lesions precisely.

Adolescent ; Adult ; Aged ; Brain ; pathology ; surgery ; Child ; Echoencephalography ; Female ; Humans ; Intraoperative Period ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neurosurgical Procedures ; methods ; Prospective Studies ; Young Adult

BACKGROUNDAn early identification of the composition of arterial thrombus may have diagnostic, therapeutic, and prognostic implications. The variation of magnetic resonance (MR) signal intensity between white and red thrombi, especially in the susceptibility sensitive MR sequence, remains unknown. Our research was to evaluate the feasibility of MRI in differentiating of white and red thrombi with a phantom study.

METHODSA total of 12 red and 12 white thrombi were prepared with the venous blood. Examination of the phantom was completed using a 3.0T MR unit, including fluid attenuated inversion recovery (FLAIR) T1, T2-weighted imaging (T2WI), FLAIR T2, T2 gradient echo (T2 GRE) imaging, and susceptibility weighted angiography sequences (SWAN). MR signal intensity patterns of the thrombi were objectively classified as hyperintensity, isointensity and hypointensity, compared with the background agar. The volume of thrombus was calculated and correlated with its signal intensity.

RESULTSFor white thrombi, 11/12 clots showed hyperintensity and 1/12 showed isointensity in FLAIR T1 images. In T2WI, 6/12 clots showed hyperintensity, 3/12 isointensity, and 3/12 hypointensity. In FLAIR T2, 8/12 clots showed hyperintensity and 4/12 showed isointensity. In T2 GRE, 3/12 clots showed hyperintensity and the remaining 9/12 clots showed isointensity. In SWAN, 5/12 clots demonstrated hyperintensity and 7/12 isointensity. For the red thrombus, 12/12 clots demonstrated hyperintensity in FLAIR T1, T2WI, and FLAIR T2 sequences. In T2 GRE and SWAN sequences, 3/12 clots displayed hypointensity and the remaining 9/12 clots showed slight hyperintensity. Thrombi with hypointensity displayed in T2 GRE and SWAN sequences were significantly larger than those with hyperintensity.

CONCLUSIONSDifferentiation of white and red thrombi with conventional MR sequence is unreliable, because both kinds of thrombi do not possess unique signal intensity features in these sequences. Red thrombus may or may not show hypointensity in the susceptibility sensitive MR sequences, depending on its size and time course.

Humans ; Magnetic Resonance Imaging ; methods ; Phantoms, Imaging ; Thrombosis ; diagnosis ; pathology