Paul Lauterbur dies at age 77

The father of Magnetic Resonance Imaging passed away on Tuesday:

Physicist Paul C. Lauterbur, who received a 2003 Nobel Prize in Physiology or Medicine for giving physicians the ability to look inside the human body without using harmful radiation, died Tuesday at his home in Urbana, Ill.

He was 77 and had been suffering from kidney disease.

research money well spent

news flash: emotions sometime trump rational thought! Shocking, I know. Though I was intrigued at how the fMRI paradigm in this case provides a neat empirical example for why prisoner’s dilemma models don’t translate well into real-world practice:

A classic economic example is the “ultimatum game,” in which one participant gets 10 $1 bills (or loonies, in Canada). He chooses how many to offer to a second participant. If she accepts the offer, the money is split the way the first participant suggested; if she rejects the offer, nobody gets anything.

Logically, the first participant can maximize his money by offering a single dollar, because logically the second participant should accept that as being better than nothing. In real life, however, the second participant, if offered only a dollar or two, almost always rejects the offer.

Functional MRI scans of brain activity show that a low offer stimulates an area associated with negative emotions, including anger and disgust. It seems the second participant would rather punish the first participant for making such an insulting offer than make an easy buck. And usually, the person making the offer understands this and offers something close to an even split, averaging about $4.

I don’t really see why the above reasonable decision-making process is inherently non-rational or “emotional” though. Doesn’t it make good rational sense to “punish” someone making a lowball offer, so they are motivated to offer you more up front?

PET and MRI

An editorial in the Journal of Nuclear Medicine (J Nucl Med. 2007 Mar;48(3):331. PMID: 17332606) argues that combination PET/MRI systems are the future and will supplant PET/CT:

In a number of ways, the path to PET/MRI has been reverse of that to PET/CT. The first PET/CT design emerged from industry–academia collaboration and was a prototype for human clinical use that eventually stimulated a commercial response and led to the development of PET/CT for imaging small animals. In contrast, PET/MRI began with the small-animal design and then, over a decade later, the first PET/MRI brain images were acquired on a dedicated prototype system, following an impressive industrial backing that far exceeded that of the early PET/CT developments.
[…]
A mere 2 y after the advent of commercial PET/CT, Johannes Czernin from UCLA, at the 2003 annual DGN meeting, commented that “PET/CT is a technical evolution that has led to a medical revolution.” Today, at the dawn of PET/MRI, it may be said that “PET/MRI is a medical evolution based on a technical revolution.” Although PET/CT appears to have replaced stand-alone PET for most oncologic indications, it is reasonable to assume that PET/MRI will be the preferred imaging option for neurologic and central nervous system indications. Without doubt, such dual-modality combinations are here to stay because they incorporate the diagnostic power of PET. Thus, PET/CT and PET/MRI, by virtue of their combined anatometabolic imaging, will lead to a “new-clear” medicine and the demise of “unclear” medicine.

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NSFW MRI: Sex at 1.5T

That’s “not safe for work”, not “national science foundation” up there in the acronym. It was surely inevitable that this amazing, subtle and elegant technology would eventually be applied to more scatological pursuits. The following paper is a classic in this genre.

Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal.

OBJECTIVE: To find out whether taking images of the male and female genitals during coitus is feasible and to find out whether former and current ideas about the anatomy during sexual intercourse and during female sexual arousal are based on assumptions or on facts. DESIGN: Observational study. SETTING: University hospital in the Netherlands. METHODS: Magnetic resonance imaging was used to study the female sexual response and the male and female genitals during coitus. Thirteen experiments were performed with eight couples and three single women. RESULTS: The images obtained showed that during intercourse in the “missionary position” the penis has the shape of a boomerang and 1/3 of its length consists of the root of the penis. During female sexual arousal without intercourse the uterus was raised and the anterior vaginal wall lengthened. The size of the uterus did not increase during sexual arousal. CONCLUSION: Taking magnetic resonance images of the male and female genitals during coitus is feasible and contributes to understanding of anatomy.

Schultz et al, BMJ. 1999 Dec 18-25;319(7225):1596-600. PMID 10600954.

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brain scans and superbowl ads

I am sure that this experiment was initially conceived by grad students:

FMRI scans while watching superbowl ads

FKF Applied Research and the UCLA Ahmanson Lovelace Brain Mapping Center have released their Second Annual Ranking of the most effective Super Bowl ads using fMRI (functional Magnetic Resonance Imaging) brain imaging. Many of the Super Bowl ads stoked regions of the brain associated with anxiety, including the amygdala.

Compared to last year’s ads there was much more anxiety, and far less positive emotion in these highly touted commercials. “This clearly was the year of the amygdala, the brain’s ‘threat detector,” said Dr. Joshua Freedman UCLA Clinical Assistant Professor of Psychiatry and a co-founder of FKF Applied Research. “Much of the anxiety seemed caused by violence, but was also rooted in economic fears. The Nationwide ad had a spike when Kevin Federline was revealed to be working in fast food, and also when the GM robot turned out to be OK but afraid for its job.”

FKF Applied Research and Dr. Marco Iacoboni’s group at the UCLA Ahmanson Lovelace Brain Mapping Center recruited men and women ages 18-34 to watch this year’s Super Bowl ads. The subjects viewed the ads while in UCLA’s high-field fMRI scanner, which monitors the activity in their brains.

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short-axis PROPELLER

One of the more interesting abstracts from last year’s ISMRM in Seattle has now been published as a full manuscript:

Propeller EPI in the other direction

A new propeller EPI pulse sequence with reduced sensitivity to field inhomogeneities is proposed. Image artifacts such as blurring due to Nyquist ghosting and susceptibility gradients are investigated and compared with those obtained in previous propeller EPI studies. The proposed propeller EPI sequence uses a readout that is played out along the short axis of the propeller blade, orthogonal to the readout used in previous propeller methods. In contrast to long-axis readout propeller EPI, this causes the echo spacing between two consecutive phase-encoding (PE) lines to decrease, which in turn increases the k-space velocity in this direction and hence the pseudo-bandwidth. Long- and short-axis propeller EPI, and standard single-shot EPI sequences were compared on phantoms and a healthy volunteer. Diffusion-weighted imaging (DWI) was also performed on the volunteer. Short-axis propeller EPI produced considerably fewer image artifacts compared to the other two sequences. Further, the oblique blades for the long-axis propeller EPI were also prone to one order of magnitude higher residual ghosting than the proposed short-axis propeller EPI.

Skare S et al, Magn Reson Med. 2006 Jun;55(6):1298. PMID: 16676335

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