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Brain tumor - Manchester

ExamCard
Prof. Jackson, Alan Manchester, University of Manchester United Kingdom

 

 

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Braintumor_manchester
Scan 1Survey_SHC (0:17)
Scan 2RefScan_SHC
Scan 3T2W_TSE (1:48)
Scan 4T2W_FLAIR (1:39)
Scan 5T1W_IR_TSE (5:02)
Scan 6DTI_SSh (1:28)
Scan 7PRESTO_perf (1:41)
Scan 8T1W_IR_TSE sag (5:02)
Scan 9T1W_IR_TSE ax (5:02)

Description

A routine brain examination consists of fast sequences in three orthogonal directions and with various contrast weightings. In case tumor pathology is found in one of these scans, additional sequences like diffusion, perfusion and post-contrast scans, are performed.

 

The first sequence is a T2-weighted TSE sequence in the axial plane. High spatial resolution is obtained in short scan time (1:48 min). Only one average is required to obtain good signal to noise ratio.

 

Next, a coronal T2-weighted FLAIR sequence is acquired. SENSE is used to reduce the scan time.

 

The third sequence of the routine brain examination is a T1-weighted Inversion Recovery sequence. Inversion delay time in this sequence is exactly half of the repetition time. By doing so, optimal T1-weighted contrast is obtained while no negative magnetization is present. Modulus images are displayed.

 

In addition, a fast single shot diffusion tensor sequence, providing six diffusion directions, is performed. Both ADC-maps and fractional anisotropy maps can be created from this dataset.

 

Subsequently, a PRESTO_perfusion sequence is performed to visualize wash-in wash-out of a contrast bolus. The PRESTO_perfusion sequence is a 3D-sequence with full brain coverage. SENSE is used to reduce the dynamic scan time, that remains below 1.5 seconds.

 

Directly after the perfusion sequence, the T1-weighted Inversion Recovery sequence is repeated in two orthogonal planes to detect possible enhancement of the lesion that was found in the routine brain examination.

 

The ExamCard is extended with Turbo spectroscopic imaging on the level of the meningioma. A dual-slice sequence with an echo time and echo spacing of 144 ms is performed. The scan time of this sequence is 10 minutes. The maximum spectral resolution that can be obtained in this sequence is about 8 Hz. This is sufficient to separate the signals of the various metabolites of interest at 3.0T.

ExamCard image steps

Axial T2W_TSE High spatial resolution in short scan time.Coronal T2W_FLAIR SENSE is used to reduce scan time.Sagittal T1W_IR_TSE With TI exactly half of TR, modulus images show optimized T1-weighted contrast
Axial T2W_TSE
Coronal T2W_FLAIR
Sagittal T1W_IR_TSE
High spatial resolution in short scan time.
SENSE is used to reduce scan time.
With TI exactly half of TR, modulus images show optimized T1-weighted contrast
Single shot diffusion tensor imaging b-value 800, low directional resolution.PRESTO_perfusion Full brain coverage, dynamic scan time less then 1.5 seconds.Axial T1W_IR_TSE Post_contrast scan shows enhancement of the meningioma.
Single shot diffusion tensor imaging
PRESTO_perfusion
Axial T1W_IR_TSE
b-value 800, low directional resolution.
Full brain coverage, dynamic scan time less then 1.5 seconds.
Post_contrast scan shows enhancement of the meningioma.

Contrast agent / injection protocol

The contrast bolus injected for the PRESTO_perfusion sequence contains 15 ml of gadolinium based contrast agent with an injection rate of 5 ml/sec, followed by a saline flush of 20 ml, with the same injection rate.

 

In general, one needs about 10 dynamics for the baseline of the contrast uptake curve, which corresponds with 13-15 seconds in this sequence. As the time required for the contrast to travel from injection site to the brain, a delay of approximately 5 seconds is required from start of scan to start of injection. This delay is programmed into the injector, meaning that both injector's start button and start scan can be pushed simultaneously.

 

If image acquisition is continued for about 2 minutes, it will be possible to see the start of contrast enhancement in leaky lesions.

Post-processing / analysis:

Both ADC-maps and FA-maps can be created in the diffusion calculation tool on the console.

The perfusion dataset can be processed on the console, generating perfusion maps in gray scale. Processing can also be performed in the quantitative analysis package on ViewForum. The calculated maps will be presented in color.

 

SpectroView is used to create metabolite maps and ratio maps in color overlay on the anatomical images. Separate spectra per voxel can be selected and displayed.

turbo spectroscopic imaging One slice from dual-slice TSI dataset.
Left spectrum from lesion, right spectrum from contr-lateral healthy side
turbo spectroscopic imaging
One slice from dual-slice TSI dataset. Left spectrum from lesion, right spectrum from contr-lateral healthy side


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Nov 26, 2004

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ExamCard
Achieva 3.0T
Release 1
Quasar Dual
Brain, Neuro
 

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