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Magnetic resonance imaging of hemorrhage
Abstract:
The magnetic resonance imaging (MRI) characteristics of evolving hemorrhage are discussed and compared with those of computed tomography (CT). Studies of 15 hematomas were undertaken in four mongrel dogs. The hematomas were created by the injection of autologous blood into the subcutaneous tissues of the thigh. The hematomas were studied serially with both MRI and CT. Pulse sequences included spin-echo (2100 msec TR, 40 and 80 msec TE) and inversion-recovery (2100 msec TR, 400 msec TI, 40 msec TE). Relaxation times (T1 and T2) were calculated in each case. CT values (H) were also obtained. In addition, 24 single and 14 serial scans of hemorrhage were obtained from 24 patients. MRI was performed on a 0.15-T resistive magnet scanner. T1 and T2 relaxation times and CT values decreased as the hematomas resolved. T1 and T2 relaxation times of intraparenchymal hemorrhage tended to remain elevated with time. MRI seems to be more sensitive than CT for the detection of hemorrhage, primarily because of superior contrast resolution.
Insights
Magnetic resonance imaging (MRI) detects hemorrhage better than computed tomography (CT). MRI and CT show decreasing values as hematomas resolve, but intraparenchymal hemorrhage shows prolonged elevated MRI signals.
Area of Science:
- Radiology
- Medical Imaging
- Biomedical Engineering
Background:
- Hemorrhage detection and characterization are crucial in clinical diagnostics.
- Comparing imaging modalities like MRI and CT is essential for optimizing patient care.
- Understanding the evolution of hematomas aids in diagnosis and treatment planning.
Purpose of the Study:
- To compare the magnetic resonance imaging (MRI) characteristics of evolving hemorrhage with computed tomography (CT).
- To evaluate the sensitivity of MRI versus CT in detecting hemorrhage.
- To analyze the changes in MRI relaxation times and CT values during hematoma resolution.
Main Methods:
- Serial MRI and CT scans were performed on canine thigh hematomas created by autologous blood injection.
- Specific MRI pulse sequences (spin-echo, inversion-recovery) were used to calculate T1 and T2 relaxation times.
- CT values (Hounsfield units) were obtained, and data from human patient scans were also analyzed.
Main Results:
- Both MRI relaxation times (T1, T2) and CT values decreased as hematomas resolved in dogs.
- Intraparenchymal hemorrhage in patients showed persistently elevated T1 and T2 relaxation times over time.
- MRI demonstrated superior sensitivity for hemorrhage detection compared to CT, attributed to its higher contrast resolution.
Conclusions:
- MRI is more sensitive than CT for detecting hemorrhage due to better contrast resolution.
- The evolution of hemorrhage can be tracked by changes in MRI relaxation times and CT values.
- MRI provides valuable insights into the temporal characteristics of resolving and chronic intraparenchymal hemorrhage.