ABSTRACT
Objective To explore the value of delay alternating with nutation for tailored excitation (DANTE)- sampling perfection with application optimized contrast using different flip-angle evolution (SPACE) sequences in quantitative evaluation of arachnoid granules (AG). Methods Thirty patients with arachnoid granules confirmed by conventional imaging were enrolled. All patients underwent SPACE and DANTE-SPACE sequences scanning. Distribution characteristics of arachnoid particles in sinus cavities and cranial plate on SPACE and DANTE-SPACE sequence images were evaluated, and the measurements were performed and statistically analyzed, including maximum cross-sectional area, longest diameter, SNR and CNR. Results A total of 43 arachnoid particles were detected with SPACE sequence, 29 in the sinus cavities and 14 in the cranial plate, while 45 arachnoid particles were found with DANTE-SPACE, 31 in the sinus cavities and 14 in the cranial plate. SPACE and DANTE-SPACE sequences showed no statistically significant difference in distribution of arachnoid particles (χ2=0.155, P=0.997). In the sinus cavity, SPACE and DANTE-SPACE sequences showed significant differences of the maximum cross-sectional area ([32.55±17.08]mm2, [29.15±16.24]mm2), the longest diameter ([7.13±2.00]mm, [6.42±1.81]mm), SNR (88.82±29.57, 83.30±32.11) and CNR (45.99±28.57, 65.33±30.96) of arachnoid particles (all P0.05). Conclusion DANTE-SPACE can effectively inhibit slow blood flow artifacts in the sinus, and accurately display arachnoid particles.
ABSTRACT
Aim To establish a method to evaluate lymphatic drainage of macromolecular tracer in cerebrospinal fluid in rats.Methods Rat cervical lymphatic blockade(CLB)models were established by occlusion of cervical lymphatic tubes and removal of cervical lymphatic nodes.The rats were divided into non CLB(normal controls) and CLB groups.~(125)I-labeled human serum albumin(~(125)I-HSA)was injected into the left lateral cerebral ventricle,and blood samples were collected and ~(125)I-HSA concentrations were detected continually within 24 hours.Concentration-time curve was drawn according to the single compartment model in pharmacokinetics.Parameters of pharmacokinetics such as area under curve(AUC),maximum concentration(C_(max)),transfer rate constant K_a and peak time(T_(max))were derived.The AUC,C_(max),K_a,and T_(max) regarding the lymphatic drainage of ~(125)I-HSA were calculated based on the differences between the two groups.Results AUC,C_(max),K_a of ~(125)I-HSA by lymphatic drainage were 51.97 mg·L~(-1)·h~(-1),2.91 mg·L~(-1),and 0.64 h~(-1),respectively.The proportion of AUC,C_(max),K_a of ~(125)I-HSA by lymphatic drainage to those of drained by both arachnoid granulations and lymphatics was 71.53%,44.02%,58.18%,respectively.T_(max) in CLB group(8.36±0.82 h)was much longer than that in non CLB group(3.57±0.54 h).Conclusions A method to evaluate lymphatic drainage of macromolecular tracer in cerebrospinal fluid in rats is successfully established.The lymphatic drainage pathway plays an important role in eliminating macromolecular substances in cerebrospinal fluid.
ABSTRACT
Objective To further improve the morphological materials of AGs by micro-dissection, histology and CT, we observed the arachnoid granulations (AGs) in middle cranial fossa. Methods Thirty-three adult cadaveric heads were used for microsurgical dissection;Histological sections of AG specimens from 3 cadaver heads were examined. Forty patients who had both normal conventional brain CT and computed tomographic venography (CTV) were retrospectively reviewed. Results In middle cranial fossa the AGs occur in the following situations in order of frequency: the middle meningeal sinus, sphenoparietal sinus, lateral foramen rotundum and cavernous sinus. AGs usually show round, oval in shape and irregular in shape. AGs can be divided into individual type and leaflet type under light microscope. The numbers of AGs were observed by microanatomy and CTV were 8.72 and 3.52 respectively. The AGs of cavernous sinus was not localized precisely on CTV. Conclusion Study of the AGs in the middle cranial fossa systematically and comprehensively enriches anatomy and image knowledge. It is helpful in neurosurgical planning and choosing operalion procedure to avoid postoperative complications.