NIH PCKD/Emory UniversityNIH PCKD/Emory University

MRI Imaging

Report 1/31/2000

OverviewOverview

• 2 Patients Scanned with NIH Protocol

• Both: Comparison with “Old Protocol”– Visual comparison– No SNR measurements performed

• No Breathhold Flow Quantification (Yet)– Philips scanner should be capable– Little experience; Validation experiments?

T2-Weighted Multi-Slice (#1)T2-Weighted Multi-Slice (#1)

Old Protocol (3 mm)Multiple Breathholds

NIH Protocol (5 mm)Single Breathhold

T2-Weighted Multi-Slice (#2)T2-Weighted Multi-Slice (#2)

Old Protocol (3 mm)Multiple Breathholds

NIH Protocol (5 mm)Single Breathhold

T2-Weighted Imaging: RemarksT2-Weighted Imaging: Remarks

• 3 mm slice thickness resolves cysts better

• Fat Suppression useful, works well

• Multiple-breathhold: registration needed– Kidney “rigid object”: overlap + affine Xform– Avoid misregistration between interlaced stacks

• Role in image analysis?

T1-Weighted 3-D (PRE-#1)T1-Weighted 3-D (PRE-#1)

Old Protocol (2.5/5 mm)=40 Single Breathhold

NIH Protocol (2.5/5 mm)=12 Single Breathhold

T1-WeightedWeighted 3-D (PRE-#2)

Old Protocol (2.5/5 mm)=40 Single Breathhold

NIH Protocol (2.5/5 mm)=12 Single Breathhold

T1-WeightedWeighted 3-D (POST-#1)

Old Protocol (2.5/5 mm)=40 90 s post-Gado

NIH Protocol (2.5/5 mm)=12 120 s post-Gado

T1-Weighted 3-D (POST-#2)T1-Weighted 3-D (POST-#2)

Old Protocol (2.5/5 mm)=40 60 s post-Gado

NIH Protocol (2.5/5 mm)=12 120 s post-Gado

T1-Weighted 3-DT1-Weighted 3-D

Ghost artifact due to heart motion (?)

Apply pre-saturation slab anterior to volume to reduce intensity?

heart

liver

T1-Weighted Imaging: RemarksT1-Weighted Imaging: Remarks• NIH protocol (=12) better overall SNR

– Pre- & post-contrast: more complex image– Segmentation easier? (CNR measurements)

• Coil placement important! Difficult?

• Pre-saturation slabs? Added acq. time?

• Older patients: – Many breathholds taxing to patient– Only 90 or 120 s post contrast?