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A special phase detector for magnetic inductive measurement of cerebral hemorrhage.

Jin G, Sun J, Qin M - PLoS ONE (2014)

Bottom Line: The noise and drift decreased as the frequency decreased.The results are in agreement with those from previous reports.The results from the injection group showed a similar trend of increasing phase shift change with increasing injection volume.

View Article: PubMed Central - PubMed

Affiliation: College of Biomedical Engineering, Third Military Medical University, Chongqing, China.

ABSTRACT
Cerebral hemorrhage is an important clinical problem that is often monitored and studied with expensive techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These devices are not readily available in economically underdeveloped regions of the world and in emergency departments and emergency zones. The magnetic inductive method is an emerging technology that may become a new tool to detect cerebral hemorrhage. In this study, a special phase detector (PD) was developed and used for cerebral hemorrhage detection with the magnetic inductive method. The performance indicated that the PD can achieve phase noise as low as 6 m° and a 4-hour phase drift as low as 30 m° at 21.4 MHz. The noise and drift decreased as the frequency decreased. The performance at 10.7 MHz was slightly better than that of other recently developed phase detection systems. To test the practicality of the system, the PD was used to detect the volume change in a self-made physical model of the brain. The measured phase shift was approximately proportional to the volume change of physiological saline inside the model. The change of the phase shift increased as the volume change and frequency increased. The results are in agreement with those from previous reports. To verify the feasibility of in vivo detection, an autologous blood injection model was established in rabbit brain. The results from the injection group showed a similar trend of increasing phase shift change with increasing injection volume. The average phase shift change induced by a 3-ml injection of blood was 0.502°±0.119°, which was much larger than that of the control group. The measurement system can distinguish a minimal cerebral hemorrhage volume of approximately 0.5 ml. All of the results demonstrated that the PD used with this method can detect cerebral hemorrhage.

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The physical cerebral hemorrhage model, (A).The experimental arrangement, (B).
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pone-0097179-g002: The physical cerebral hemorrhage model, (A).The experimental arrangement, (B).

Mentions: The physical cerebral hemorrhage model is shown in Figure 2A. It consists of two different-sized coils with diameters D1 = 68 mm and D2 = 220 mm, coaxially centered at a distance d = 100 mm. The coil at the top of the model is a transmitting coil (T-coil), and a receiving coil (R-coil) is in the middle. The model is made of a soft plastic capsule centered inside of an organic glass sphere. The capsule, which can be filled with a maximum of 100 ml of solution, is connected to a conduit at the bottom of the glass ball, and the conduit is connected to a syringe pump. Solutions of varying volumes and conductivities can be injected into the capsule to simulate cerebral hemorrhage. The remaining volume of the model is partially filled with physiological saline (conductivity of 0.3 Sm−1) to simulate brain tissue. The volume of the model is similar to the volume of an adult’s head.


A special phase detector for magnetic inductive measurement of cerebral hemorrhage.

Jin G, Sun J, Qin M - PLoS ONE (2014)

The physical cerebral hemorrhage model, (A).The experimental arrangement, (B).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016262&req=5

pone-0097179-g002: The physical cerebral hemorrhage model, (A).The experimental arrangement, (B).
Mentions: The physical cerebral hemorrhage model is shown in Figure 2A. It consists of two different-sized coils with diameters D1 = 68 mm and D2 = 220 mm, coaxially centered at a distance d = 100 mm. The coil at the top of the model is a transmitting coil (T-coil), and a receiving coil (R-coil) is in the middle. The model is made of a soft plastic capsule centered inside of an organic glass sphere. The capsule, which can be filled with a maximum of 100 ml of solution, is connected to a conduit at the bottom of the glass ball, and the conduit is connected to a syringe pump. Solutions of varying volumes and conductivities can be injected into the capsule to simulate cerebral hemorrhage. The remaining volume of the model is partially filled with physiological saline (conductivity of 0.3 Sm−1) to simulate brain tissue. The volume of the model is similar to the volume of an adult’s head.

Bottom Line: The noise and drift decreased as the frequency decreased.The results are in agreement with those from previous reports.The results from the injection group showed a similar trend of increasing phase shift change with increasing injection volume.

View Article: PubMed Central - PubMed

Affiliation: College of Biomedical Engineering, Third Military Medical University, Chongqing, China.

ABSTRACT
Cerebral hemorrhage is an important clinical problem that is often monitored and studied with expensive techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These devices are not readily available in economically underdeveloped regions of the world and in emergency departments and emergency zones. The magnetic inductive method is an emerging technology that may become a new tool to detect cerebral hemorrhage. In this study, a special phase detector (PD) was developed and used for cerebral hemorrhage detection with the magnetic inductive method. The performance indicated that the PD can achieve phase noise as low as 6 m° and a 4-hour phase drift as low as 30 m° at 21.4 MHz. The noise and drift decreased as the frequency decreased. The performance at 10.7 MHz was slightly better than that of other recently developed phase detection systems. To test the practicality of the system, the PD was used to detect the volume change in a self-made physical model of the brain. The measured phase shift was approximately proportional to the volume change of physiological saline inside the model. The change of the phase shift increased as the volume change and frequency increased. The results are in agreement with those from previous reports. To verify the feasibility of in vivo detection, an autologous blood injection model was established in rabbit brain. The results from the injection group showed a similar trend of increasing phase shift change with increasing injection volume. The average phase shift change induced by a 3-ml injection of blood was 0.502°±0.119°, which was much larger than that of the control group. The measurement system can distinguish a minimal cerebral hemorrhage volume of approximately 0.5 ml. All of the results demonstrated that the PD used with this method can detect cerebral hemorrhage.

Show MeSH
Related in: MedlinePlus