DÜSSELDORF, Germany — The trend in ultrasound is to smaller, even pocket-sized, transducers that trade off resolution for portability in order to move with doctors to patients for quick views of internal organs.

Meanwhile magnetic resonance imagine (MRI) is moving in the opposite direction with larger, heavier, more massive machines generating more powerful magnetic fields to display greater detail for characterizing disease.

A chat with Siemens (Erlangen, Germany) during the MEDICA trade exhibition here confirmed the installation in Vienna last month of a hulking 7 Tesla MRI.

For comparison, you most recent MRI was likely performed by a conventional 1.5 Tesla MRI widely installed at most hospitals and clinics.

And Siemens spokesman said the company has been installing since May, 2008 a 9.4 Tesla MRI at a leading European research center in Jülich, Germany that is expected to become operational in 2009 to visualize previously inaccessible structures and metabolic processes of the brain.

To help with the task, the Jülich Research Center also has an IBM Blue Gene/ P supercomputing system.

Yet far away from this German heavy industry at the opposite end of the earth's magnetic field in New Zealand, researchers have developed the world's smallest MRI, a table top machine no bigger than a crock pot cooker on a kitchen counter.

Proportionate to its size it also generates the world's smallest magnetic field of just 0.005 Tesla.

Someone needed to do it, perhaps. But why?

"To measure and then examine the relaxation times of hydrogen molecules excited by magnetic pulse," explained an enthusiastic Markus Michel, an engineer with the Fraunhofer Institut für Biomedizinische Technik (IBMT; St. Ingbert, Germany).

"The mean parameters for these relaxation times give curves that are characteristic to materials," he said with a sincerity that always makes it worth the trip to Fraunhofer's displays of advanced research work that is always a bit off the beaten track of MEDICA with its shopping mall displays of forceps, syringes and other more practical medical tools.

Roughly translated, the mini MRI, hooked up to a spectometer, could be used to characterize liquids the way MRI is used routinely in clinics to characterize and diagnose tissue.

The body is filled with fluids, after all, and maybe, someday this work will lead to a table top clinical tool for rapid exams in pathology labs.

Meanwhile the New Zealanders are actually using the portable MRI in Antarctica, where liquids are becoming increasingly easier to find, to measure the effects of climate change by analyzing the structure of ice masses and drilled ice cores.

The Terranova-MRI manufactured by Magritek (Wellington, New Zealand) uses a permanent magnet, a super strong version of the kind most people have at home on the refrigerator door, rather than the electrically charged high-power fields of conventional MRI that have to be cooled with liquid helium and nitrogen.

Magritek is a spin-off company, with technology transferred from research teams at Massey University and Victoria University of Wellington.

Fraunhofer IBMT has agreed to help Magritek, and will collaborate on future technical developments of the overall system and develop new applications.

In contrast to the New Zealand start-up, IBMT is one of 56 institutes that are part of Fraunhofer-Gesellschaft, the largest organization for applied research in Europe with 40 different locations in Germany and 13,000 employees.

Pill camera performing somersaults

Another project for the IBMT group presented at MEDICA was the Nano based capsule-Endoscopy with Molecular imaging and Optical biopsy (NEMO) project funded by the European Union.

The Magnetic Resonance Group of IBMT is charged as a project partner with maneuvering of the capsule camera inside the body.

It should be remembered that once a capsule camera is ingested by a patient, its locomotion is powered by natural digestive processes and gravity, both aligned in the same southerly direction.

The NEMO project wants to reverse this trajectory, or at least control the descent, in order to focus on areas of interest that have been highlighted by ingested or injected biomarkers that serve as "beacons" for a disease state, such as a tumor.

In preliminary experiments in animals the capsules have been swiveled, somersaulted, stopped and moved by an external magnetic field that controls the device, validating the new magnetically sensitive features the Fraunhofer group has loaded into the capsule.

This maneuvering has proven to be effective in enhancing visualization in the esophagus and stomach and was safe when the internal magnetic arrangement was matched to the external magnet, according to Frank Volke with IBMT.

He said tests on human volunteers are now being prepared.