CSI WH

Listen to the story

By Alex Crowley

Darlene Ketten is not your typical Hollywood CSI investigator. Unlike the TV-celebrity who sports a tight pantsuit and fresh lip-gloss, Ketten sits comfortably in her Woods Hole Oceanographic Institution laboratory in jeans and a sweater. She is small framed, with large, expressive eyes. Ketten is a senior scientist in the biology department of WHOI, in a facility called "CSI." In this case, CSI stands for Computerized Scanning and Imaging, not Crime Scene Investigation. But her job as a clinical researcher might fit well into a veterinary version of the prime time hits. Ketten scans and autopsies marine mammals, like they do in humans, to diagnose problems both before and after death.

It's a bit ghoulish to spend your days looking at dead animals, but in one sense, you're their best last advocate, just like you are for a human. And you let the body tell you what it can, and especially if it's an animal that's been in care and unfortunately dies. You let that body inform you how to take care of another one perhaps differently.

Ketten generally has two or three new cases each week, and she works on her own research on marine mammals and hearing every day. Ketten scans the marine specimens using a CT scanner, short for computerized tomography scanner, which uses X-rays to identify a problem and inform suggestions for treatment.

Darlene Ketten: "There might be an animal that is stranded, they are trying to make a decision about it, that they think they are going to take it into rehab, rehabilitation, where they might try to save the animal, or they may have to euthanize it. They may have to put it down. One of the things is, they try to make that decision on the beach as quickly as possible, but sometimes they need a little more information."

Specimens come to Dr. Ketten's lab from all over the world, in many different shapes and sizes. Smaller species, like cuttle fish, can be scanned while in a bowl full of water. Larger specimens, like an 18-foot beaked whale, weighing over 2000 pounds, have to be lifted into the lab by a hoist and lowered onto the CT scanner table for examination.

Once the specimen is in place, Ketten leaves the scanner room and goes through leaded doors into an adjoining control room. This is similar to when nurses leave the room while humans get X-rayed.

The control room has three computer monitors and a leaded window that looks out onto the CT Scanner. Ketten then enters the specimen into a database on the computer and the CT scan begins. The specimen slowly moves on the table into the doughnut-shaped hole, where x-ray images and data are acquired very rapidly. An entire dolphin, for example, can be scanned in only five minutes.

Once the specimen has been scanned, the images are displayed on a computer monitor in what are called cross sections. These are smaller slices of individual parts of the specimen. For example, the flipper of a dolphin, broken down into 1-millimeter slices, showing each and every joint. The images appear on the monitor in black and white and gray, like an x-ray. Ketten can use the images to identify a disease or trauma and suggest a way to rehabilitate the animal. She has many success stories.

Darlene Ketten: "Another case was a rather nice turtle that was brought in except she wasn't swimming properly. And they were concerned that they were going to have to euthanize her. Well what we found was that she had a joint infection, a bone infection at the joint, and the cartilage was inflamed, and they treated that. And at first they thought it was a malformed flipper or a broken flipper and they were going to have to put her down. "

But not all animals can be treated, and many arrive as strandings, in need of an autopsy, or what is called a necropsy in animals, to determine the cause of death.

Darlene Ketten: "So we learn a great deal by looking at things post-mortem, because of course one of the problems is you can't go up to an animal like a bailene whale or a hippo and say, 'Where does it hurt?' You can, but you're not going to get much of an answer!"

Once a specimen has been scanned, it is lifted off the table by the hoist and brought into the necropsy room, where it is lowered onto a dissection table, or put into the minus 70 degree ultra low freezer to preserve it.

The animals are hung upright in the freezer, as opposed to laying flat on the floor, to keep the organs and tissues from crushing or distorting.

When it's time for the frozen specimens to be examined, they are thawed slowly in a pit of water with controlled conditions. The water pit can hold specimens of up to 1000 pounds. But Ketten says they don?t always have to necropsy an entire animal, perhaps only the head.

Darlene Ketten: "In some instances, we don't get a whole animal to do. Like that bucket right there is actually a blue whale ear. Um, and so we're looking at the ears to see whether or not the animal was stranded in part because it had a hearing problem."

To perform a necropsy, Ketten and her technicians will have to cut into the animal using a large oscillating saw, called the Striker saw.

These saws are specialized to be able to cut through bone, as opposed to soft tissue. Ketten will cut open the animal's skull with it and lift the brain out for examination. Or, she will examine the soft tissues to get its life history, like incidences of injury or trauma.

Darlene Ketten: "The most fun part is when something new happens--a new species, or we figure out a way to look at it better and get more information out of it. When it all clicks. When the jigsaw puzzle goes together, and you see something new."

Ketten has close to 100 specimens of different species in her laboratory freezer at the moment, and she has an archive of about 1200 CT scans. Many researchers use her scans for their own research, as it has become sort of a database of different species' structures.