Liver Protocol

Liver Protocol

Liver MR imaging may be helpful in detecting and diagnosing lesions especially when other radiological studies are inconclusive. Small tumors and hepatic masses in a diffusely fatty liver may not be easilydiscerned on CT or US. In such cases, MR imagingmay be the modality of choice. Indications include but are not limited to evaluation of parenchymal disease such as cirrhosis and hemosiderosis, characterization of a suspected benign lesions such as hemangioma, FNH, and adenoma, and demonstration of dysplastic nodules or HCC in the cirrhotic liver. Donor liver volume and vascular anatomy prior to liver transplantation can be reliably demonstratedwith 3D MR Angiography an optimally timed contrast-enhanced dynamic 3D gradient echo study (see reimbursable ICD9 codes).

Scheduling Guidelines

· First Ask:

1. Why is the liver MRI being requested?..................

2. What prior liver imaging (CT, US) has been done? …………..If prior imaging was performed in another imaging center, please ask for a copy of report and ask patient to bring in films if possible.

3. Have you had prior liver or gallbladder surgery? ………..…….. What operation? ………………

4. Have you ever had cancer? ……….. What type of cancer? ………….…… When was the cancer diagnosed? ……………….

5. Have you ever been diagnosed any liver disease, such as hepatitis or cirrhosis? .............................

6. What is the alpha fetoprotein level? ……LDH: ……SGPT: ….. SGOT: …… Alkaline Phosphatase: ……Total Bilirubin: ……

Patient Preparation

· Start intravenous line (20 or 22 gauge IV). If iv caliber is small (i.e. 22 gauge) then warm the Gd contrast up to body temperature to reduce its viscosity.

· Valium (5-10mg po) or Xanax (1-2 mg po) if patient is claustrophobic

· Ear plugs

Coil: 8 channel body coil

Patient positioning: Supine, feet first. The arms are positioned comfortably next to abdomen. Patient must have comfortable pillow for head and a cushion under the knees to relieve back pressure.

Landmark: Three fingers below the xyphoid at rib cage margin.

ASSET Axial Dual Echo

Pre-Gd Dyn 3D FS Ax FAME

Post-Gd Dyn 3D FS Ax FAME

ASSET FS Coronal T1

Fast 2D TOF

Portal Vein PC

Coil

Full FOV

Upper

Full FOV

Upper

IMAGING PARAMETERS

Plane

3-Plane

Axial

Coronal

Axial

Coronal

Axial

Oblique

Mode

Pulse Sequence

Localizer

Fast GRE

SSFSE

Fast SPGR

Fast TOF SPGR

Fast 2D PC

Imaging Options

NPW

Calib,Fast

Asset,SS,Fast

Asset,Fast

MPh,ZIP2,

ZIP512,Fast

MPh,ZIP2,Fluoro,ZIP512,Fast

Asset,VBwFast

FC,Seq,ZIP512,Fast

FC,Gat,Seq,

Fast

SCAN TIMING

# of Echoes

180

Minimum

Min Full

Minimum

225

150

Minimum

Flip Angle

Bandwidth

31.25

62.50

83.33

62.50

31.25

15.63

ETL

BSP TI

Prep Time

Auto

ADDITIONAL PARAMETERS (see attached instructions)

SAT

I,S

F: sp

Fat

Multiphase

Phase/loc:1

Phases/loc: 3

Delay: 120 ms

ACQUISITION TIMING

Freq

256

512

256

Phase

128

256

224

128

160

256

128

NEX

Phase FOV

0.60

0.75

#acq/locs Bef Pause

Freq DIR

R/L

S/I

R/L

S/I

R/L

Unswap

Auto Cent Freq

Water

Auto Shim

Yes

Phase Correct

Yes

Contrast

Yes (20 ml Gd)

SCANNING RANGE

FOV

Slice Thickness

Spacing

Start - End

0.0

I240-S240

A104.3-P79.7

S210.9-I5.1

S21-S29

0-S1

A98.1-P48.9

I1000-I600

A/P: 44

# Slices

5/plane

Slab: 1

Locs per slab

Scan Time

0:31

0:12

0:23

0:15

0:13

0:22

1:08

0:13

8:39

0:27

Series 1: 3-plane localizer

This is a quick localizer sequence obtained in three planes which is used to confirm optimal patient positioning.

Series 2: ASSET Calibration

Array spatial sensitivity encoding technique (ASSET) is a parallel imaging technique which uses independent signals from each of the coil elements to accelerate data acquisition. Prior to image acquisition with ASSET, a single breath hold low resolution reference scan (ASSET calibration) must be run to obtain a sensitivity map for each coil in the phased array for calculating the missing k-space data. These sensitivity maps are needed to unwrap the aliasing in the ASSET scan. ASSET calibration FOV is set to 48 cm and should be prescribed from the top of the coil to the bottom of the coil.

Series 3: Coronal SSFSE (single-shot fast spin-echo)

· This sequence is ready to go. If you do not want to run 3-plane localizer, and ASSET calibration, just hit the “scan” button.

· This sequence is performed in inspiration as a guide for prescribing breath hold scans. In really large patients (large in the AP dimension), it may be useful to cover more anteriorly. When acquiring the coronal scan, use the 8 channel body coil full FOV.

Series 4: Axial SSFSE

· SSFSE sequence has some advantages over other T2 weighted imaging techniques; high SNR due to the reduced noise from ghost artifacts, less respiratory motion artifact, and higher patient cooperation compared to the long acquisition techniques. High CNR increases the lesion detection especially for non-solid lesions.

· In SSFSE, a single 90° excitation pulse is followedby sufficient 180° pulses and readouts to encode half of k-space. This sequence is very RF intensive; to avoid from exceeding the specific absorption rate (SAR) limits, a refocusing flip angle of 130° may be preferred especially at 3T rather than the usual value of 180°.

· Slice acquisition order can be either interleaved or sequential. If you do not select sequential order, the interleaved technique is used. When sequential is used, the SNR and image contrast can decrease due to cross talk.

· Scan from top of liver to bottom of liver with breath-hold (if possible).

· User CV: Fractional NEX optimization: if it is “on”, SNR and T2 weighting increase. If it is “off” the scan time is shorter.

· Maximum number of echoes is set to 260 (largest possible value). This improves image quality (SNR) at the expense of time.

· If you increase the bandwidth, image blurring may be decreased at the expense of SNR.

· Switch 8 channel body array coil to “upper”.

Series 5: Axial dual in-phase and out-of phase

The purpose of using dual-phase chemical-shift imaging is to detect lipid either in hepatic parenchyma or within hepatocellular neoplasms. This is a non-enhanced breath-hold T1-weighted spoiledgradient-echo (SPGR) sequence in which periodic chemically selective fat-saturationpulses have been incorporated. Short TRs and short TEs are used. When TE is in phase (4.2 ms at 1.5T), fat and water signals combine (in-phase imaging). Out-of-phaseimaging is performed with a TE of 2.1 ms at 1.5T. Fat will lose signal intensity on out-of phase images, because the signals from fat and water protons cancel each other. This sequence is also helpful to look for iron deposition in liver parenchyma. In patients with iron accumulation, parenchymal signal is lower on the longer TE in-phase images.

· Select 2 echoes, system automatically acquires in and out-of-phase images.

· User CV: Select turbo mode before entering the matrix values. Turbo mode reduces the RF pulse width and therefore shortens the TR. As the turbo mode gets faster, tissue contrast decreases but vessel-background contrast increases.

· Scan from top of liver to bottom of liver. Breath-holding is critical. Repeat as necessary for optimum image quality.

Series 6: Axial 3D Dynamic Gd (FAME)

On older scanners this was performed as out-of-phase 2D FMPSPGR with fat saturation to eliminate artifact at fat-organ boundaries. On state-of-art scanners, 3D provides higher resolution and allows zero filling (ZIP2) for overlapping reconstruction of slices. Repeat the scan multiple times with breath holding as follows:

· Pre-contrast fat-saturated 3D volume images are obtained. These provide T1-weighted information.

· Begin to administer 0.1-0.2 mmol/kg dose of Gd contrast (typically 30 ml) at a rate of 3 ml/s, and set the fluoro-triggering to detect to contrast arrival. Operator may visually follow the contrast travel through the right heart, pulmonary arteries, ascending aorta and finally descending aorta. Triggering the scan should be done when the contrast arrives to proximal segment of abdominal aorta (diaphragmatic level). As soon as the operator observes the contrast arrival, instructs the patient to hold his/her breath at the end of inspiration, and triggers the sequence. There is a 5 s delay between triggering and the beginning of actual acquisition for breathe holding instructions.

· Gd injection is followed by 20ml of saline flush at a rate of 3 ml/s.

· The first acquisition is timed for arterial enhancement. Same acquisition is performed subsequently multiple times in quick succession (10 seconds between eachto allow patients to catch their breath) to acquire the portal, hepatic venous, and equilibrium phases. The scan may be repeated as much as desired. Delayed phase imaging: If the liver is cirrhotic, a delay of 3 minutes is adequate. If there is a suspicious lesion that might be hemangioma or cholangiocarcinoma, then repeat scan every 2-3 minutes out to 10 minutes. Cholangiocarcinoma is known to enhance late.

· A chemically selective fat-saturationpulse is applied just before each partitions loop. In the saturation pulse area, choose the ‘special’. The partitionsloop is centric reordered to optimize fat-saturationuniformity.

· Zero-filling interpolation can reduce partial volume artifactson 3D MR angiograms.

· The 3D volumetric imaging technique is a modified MRA sequence. The operator, by using “IVI” option and MIP algorithms on the scanner or Windows Advantage work station can obtain reconstructions of the arterial territories.

Series 7: Post-Gd Coronal T1

The late phase delayed 2D sequence is performed using fat saturation. This includes abdomen and pelvis and should be performed with the coil set to full FOV.

Series 8: Fast 2D TOF

This sequence is performed when the study is ordered for liver donor. It produces excellent vascular motion suppression with respiratory compensation (ROPE) which is especially useful in patients who cannot breathe hold.

Billing Instructions

Reimbursable ICD9 Codes
570	Acute and subacute necrosis of liver
571	Chronic liver disease and cirrhosis
	571.0	Alcoholic fatty liver
	571.2	Alcoholic cirrhosis of liver
	571.3	Alcoholic liver damage, unspecified
	571.4	Chronic hepatitis
	571.5	Cirrhosis of liver without mention of alcohol
	571.6	Biliary cirrhosis
	571.8	Other chronic nonalcoholic liver disease
	571.9	Unspecified chronic liver disease without mention of alcohol
572	Liver abscess and sequelae of chronic liver disease
	572.0	Abscess of liver
	572.3	Portal hypertension
	572.8	Other sequelae of chronic liver disease
573	Other disorders of liver
	573.0	Chronic passive congestion of the liver
	573.1	Hepatitis in viral diseases classified elsewhere
	573.2	Hepatitis in other infectious diseases classified elsewhere
	573.3	Hepatitis, unspecified
	573.4	Hepatic infarction
	573.9	Unspecified disorder of liver
155.0	Primary malign neoplasm
155.1	Malign neoplasm of intrahepatic bile ducts
155.2	Liver, not specified as primary or secondary
211.5	Benign neoplasm
228.0	Hemangioma
239	Unspecified
197.7	Metastasis
789	Hepatomegaly
751.6	Congenital anomalies of liver
V42.7	Transplanted Liver
V59.6	Liver Donor
195.2	Malignant Neoplasm of Abdomen

Normal Liver Dictation Template

Clinical Statement:

Technique: 1.5 Tesla, phased array, coronal and axial SSFSE, axial in-and out-of-phase spoiled gradient echo, 3D dynamic Gd-enhanced (FAME) and post-Gd fat suppressed coronal T1 sequences.

Findings:

Ascites: No ascites

Liver: The liver is normal in size, contour and has normal signal intensity on all sequences. No focal hepatic lesions are identified.

Portal Vein: Widely patent

Hepatic Veins: Widely patent

Biliary: No dilatation

Gall Bladder: Normal in size and configuration, no cholelithiasis, no inflammation

Spleen: Normal size and signal, no focal lesions

Pancreas: Normal in size and contour, normal signal intensity on all sequences, no focal lesions are identified.

Adrenal Glands: No masses identified
Right Kidney: Normal in size, contour, signal intensity. No pelvicaliceal dilatation, no masses.

Left Kidney: Normal in size, contour, signal intensity. No pelvicaliceal dilatation, no masses.

Retroperitoneum: No adenopathy

Impression: Normal MR of liver; no lesion identified.

Liver Hemangioma Dictation

Technique: 1.5 T, phased array coil, coronal and axial SSFSE, axial dual echo SPGR, 3D dynamic Gd-enhanced (FAME) and post-Gd fat suppressed coronal T1 sequences.

Findings: A…. x…. cm lesion is identified in the …….. lobe of the liver (segment #). It is T1 dark, homogeneously T2 bright with smooth margins and enhances with Gd initially with peripheral puddling which gradually progresses to homogeneous enhancement which persist on delayed images. There is no lesion suspicious for metastasis or malignancy. The liver size, contour and signal intensity are normal. The portal vein and hepatic veins are widely patent. There is no biliary dilation.

The pancreas, spleen, adrenal glands and kidneys are normal. No retroperitoneal lymphadenopathy is identified.

Impression: ….. x …. cm hemangioma in …….. lobe (segment….) of liver; otherwise normal abdominal MRI findings.