# Presentation: 498634

## Standardizing Image Acquisition

- Jeffrey L. Evelhoch, PhD
- Director
- Medical Sciences (Imaging)

## Why standardize acquisition?

- Best Image Processing Ever

## Issues to consider

**Manufacturer-based differences**
**Technology changes**
**Not all sites are created equal**
**QC for quantitative v. diagnositic imaging**
**Appropriate method depends on:**
- Exact question
- Image analysis methods
**Who will ‘mind the shop’**

## An Example – Consensus Protocol

**DCE-MRI**
**Early phase clinical trials for drugs targeting tumor blood supply****      **
**Low molecular weight gadolinium chelate**_**s**_
**1.5 Tesla**

## A Brief History

**October 1999: NCI Workshop ******** consensus recommendation**
- Included both treatment response and breast diagnosis
**March 2002: CRUK PTAC Workshop ******** consensus recommendation**
- Treatment response in early clinical trials
**Nov 2004: NCI Workshop ******** consensus recommendation**
- Treatment response in early clinical trials

## NCI Workshop Participants

**Jeffrey Abrams**
**Thomas Chenevert**
**Laurence Clarke**
**Jerry Collins**
**Jeffrey Evelhoch**
**Susan Galbraith**
**Michael Knopp**
**Jason Koutcher**
**Martin Leach**
**Nina Mayr**
**Daniel Sullivan**
**Edward Ashton**
**Peter Choyke**
**Patricia Cole**
**Gregory Curt**

**Milind Dhamankar**
**Michael Jacobs**
**Gary Kelloff**
**Adrian Knowles**
**Lester Kwock**
**Peter Martin**
**Teresa McShane**
**Anwar Padhani**
**Stefan Roell**
**Mark Rosen**
**Gregory Sorensen**
**Charles Springer**
**Michael Tweedle**
**Donald Williams**
**Antonio Wolff**

## Specific recommendations for

**Type of measurement****           **
**Requirements for contrast agent injection**
**Primary endpoints**
**Secondary endpoints**
**Nomenclature**
**Data reduction**
**Region of interest**

**Images acquired prior to contrast injection **
**Dynamic acquisition protocol**** **
**Measurement requirements for  primary endpoints**
**Trial design**
**Image analysis**

## Let’s consider issues & approaches adopted to address those issues

## Manufacturer-based differences

| e.g., Sequence names |  |  |  |
| --- | --- | --- | --- |
| Sequence | GE | Philips | Siemens |
| Gradient echo | GRASS | FFE | GRE |
| Spoiled Gradient echo | SPGR | T1FFE | FLASH |
| Inversion Recovery | MPIR | IR-TSE | TurboIR |

## Approaches

**Need access to experts on all systems**
**Use basic sequences (differences smaller)**
**Tweak parameters to match as closely as possible**
**Make certain reconstruction methods are as close as possible**
**Same reference standard on all systems**

## Technology changes  keep it simple

**1.5-T (for near future)**
**Basic sequences (less likely to change with upgrades)**
**Parameters (at least) one step back from cutting edge**
**Use analysis with considerable experience within community, most forgiving**
**Revisit recommendations periodically**

## Not all sites are created equal 

**Keep it simple**
**Training, training, training, ...**
**Routine QC**
**Careful monitoring**
**Immediate feedback**

## QC for quantitative v. diagnositic imaging

**Requires higher performance**
- MR system
- Sequences
- Set-up procedures
- Radiological processes
**Better here**

**or here?**

## Appropriate method

**For breast cancer diagnosis want dynamic temporal-spatial resolution trade-off **

- M. Schnall,MRM 2001

## Who will ‘mind the shop’?

## Summary of key recommendations fordata acquisition

## General Issues

**Entry criteria should consider tumor size in relation to pharmacological mechanisms, MRI resolution, sensitivity to motion and potential confounding factors from previous treatment (e.g., radiation) or rapid tumor growth rates**
**Tumors in a fixed superficial location should be at least 2 cm in diameter; other tumors should be at 3 cm in diameter**
**Adjust orientation so that motion is in-plane when motion effects cannot be avoided (e.g., liver, lungs)**** **

## Pre-injection

**Acquire high quality clinical images of entire anatomic region (preferably in two orthogonal planes)**
**Acquire T1- and T2-weighted images registered in the same planes as the dynamic data **
**If possible, measure T1 (using same resolution and field of view for dynamic data) **

## Contrast agent injection 

**Use power injector to minimize variation **
**Injection dose should be standardized by weight**
**15-30 sec for total injection, at least 20 cc saline flush **
**Document injection site, use same site for subsequent studies in same subject**
**Minimum of 24 h between studies**

## Dynamic study (I)

**For first 150 sec after bolus injection, use fastest sampling possible consistent with spatial resolution/anatomic coverage requirements, but not slower than 20 sec temporal resolution**

## Dynamic study (II)

**Acquire data out to at least 8 min (continual sampling is optional)**
**If possible, include in imaging volume a normalization function (e.g., arterial or other tissue)**
**For serial studies, imaging volume of interest should be adjusted to sample same region of tumor**

## Summary

**Development & application of appropriate protocol requires close academic-industry interaction**
**For multi-center studies**
- Keep it as simple as possible while still getting the required info
- Clarity & education up front is essential
- Non-standard methods require substantial continuous support