Posts tagged CT scans
Articles and news from the latest research reports.
The Shrinking of the Hobbit’s Brain
Where do Hobbits come from? No, not the little humanoids in the J. R. R. Tolkien books, but Homo floresiensis, the 1-meter-tall human with the chimp-sized brain that lived on the Indonesian island of Flores between 90,000 and 13,000 years ago. There are two main hypotheses: either the creature downsized from H. erectus, a human ancestor that lived in Africa and Asia and that is known to have made it to Flores about 800,000 years ago and may have shrunk when it got there—a case of so-called “insular dwarfism” often seen in other animals that get small when they take up residence on islands. Or it evolved from an even earlier, smaller-brained ancestor, such as the early human H. habilis or an australopithecine like Lucy, that somehow made it to Flores from Africa. The insular dwarfism hypothesis had fallen out of favor recently, however, because many researchers thought that the Hobbit’s brain, often estimated at 400 cubic centimeters in volume, was too small to have evolved from the larger H. erectus brain, which was at least twice as big. But a new study, published online today in the Proceedings of the Royal Society B, finds from CT scans of the Hobbit’s brain that it was actually about 426 cubic centimeters in volume. The team calculates that this is big enough to make the island dwarfism hypothesis considerably more plausible once the body size differences between the Hobbit and H. erectus—which was nearly twice as tall—are adjusted for.
No Need for Routine Repeated CT Scans after Mild Head Trauma, Reports Neurosurgery
When initial computed tomography (CT) scans show bleeding within the brain after mild head injury, decisions about repeated CT scans should be based on the patient’s neurological condition, according to a report in the January issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.
The study questions the need for routinely obtaining repeated CT scans in patients with mild head trauma. “The available evidence indicates that it is unnecessary to schedule a repeat CT scan after mild head injury when patients are unchanged or improving neurologically,” according to the study by Dr. Saleh Almenawer and colleagues of McMaster University, Hamilton, Ont., Canada.
Are Repeated Scans Necessary after Mild Head Trauma?
In a review of their hospital’s trauma database, the researchers identified 445 adult patients with mild head injury who had evidence of intracranial hemorrhage (ICH)—bleeding within the brain—on an initial CT scan. In many trauma centers, it’s standard practice to schedule a second CT scan within 24 hours after ICH is detected, to make sure that the bleeding has not progressed.
To evaluate the need for routine repeated scans, Dr. Almenawer and colleagues looked at how many patients needed surgery or other additional treatments, and whether the change in treatment was triggered by changes in the patients’ neurological condition or based on the routine CT scan alone. (For patients whose neurological condition worsened, CT was performed immediately.)
Overall, 5.6 percent of the patients required a change in treatment after the second CT scan. Most of these patients underwent surgery (craniectomy) to relieve pressure on the brain. Nearly all patients who underwent further treatment developed neurological changes leading to immediate CT scanning.
Just two patients had a change in treatment based solely on routine repeated CT scans. Both of these patients received a drug (mannitol) to reduce intracranial pressure, rather than surgery
Decisions on CT Scans Can Be Based on Neurological Status
Dr. Almenawer and colleagues extended the same method to patients reported in 15 previous studies of CT scanning after mild head injury. Including the 445 new patients, the analysis included a total of 2,693 patients. Overall, 2.7 percent of patients had a change in management based on neurological changes. In contrast, just 0.6 percent had treatment changes based on CT scans only.
Bleeding within the brain is a potentially life-threatening condition, prompting routine repeated CT scans after even mild head injury. The researchers write, “Although CT scanners are very useful tools, in an era of diminishing resources and a need to justify medical costs, this practice needs to be evaluated.” Each scan also exposes the patient to radiation, contributing to increased cancer risk.
The new study questions the need for routine repeated CT scans, as long as the patient’s neurological condition is improving or stable. “In the absence of supporting data, we question the value of routine follow-up imaging given the associated accumulative increase in cost and risks,” Dr. Almenawer and coauthors conclude.
Neurological examination is the “simple yet important” predictive factor leading to changes in treatment and guiding the need for repeat CT scanning after mild head injury, the researchers add. They emphasize that their findings don’t necessarily apply to patients with more severe head injury.
(Source: newswise.com)
MRIs Reveal Signs of Brain Injuries Not Seen in CT Scans
Hospital MRIs may be better at predicting long-term outcomes for people with mild traumatic brain injuries than CT scans, the standard technique for evaluating such injuries in the emergency room, according to a clinical trial led by researchers at UCSF and the San Francisco General Hospital and Trauma Center (SFGH).
Published this month in the journal Annals of Neurology, the study led by UCSF neuroradiologist Esther Yuh, MD, PhD, followed 135 people treated for mild traumatic brain injuries over the past two years at one of three urban hospitals with level-one trauma centers: SFGH, the University of Pittsburgh Medical Center and University Medical Center Brackenridge in Austin, Texas. The study was called the NIH-funded TRACK-TBI (Transforming Research and Clinical Knowledge in Traumatic Brain Injury).
All 135 patients with mild traumatic brain injuries received CT scans when they were first admitted, and all were given MRIs about a week later. Most of them (99) had no detectable signs of injury on a CT scan, but more than a quarter (27/99) who had a “normal” CT scans also had detectable spots on their MRI scans called “focal lesions,” which are signs of microscopic bleeding in the brain.
Spotting these focal lesions helped the doctors predict whether the patients were likely to suffer persistent neurological problems. About 15 percent of people who have mild traumatic brain injuries do suffer long-term neurological consequences, but doctors currently have no definitive way of predicting whether any one patient will or not.
“This work raises questions of how we’re currently managing patients via CT scan,” said the study’s senior author Geoff Manley, MD, PhD, the chief of neurosurgery at SFGH and vice-chair of the Department of Neurological Surgery at UCSF. “Having a normal CT scan doesn’t, in fact, say you’re normal,” he added.
Better Precision Tools Needed for Head Injuries
At least 1.7 million Americans seek medical attention every year for acute head injuries, and three-quarters of them have mild traumatic brain injuries – which generally do not involve skull fractures, comas or severe bleeding in the brain but have a variety of more mild symptoms, such as temporary loss of consciousness, vomiting or amnesia.
The U.S. Centers for Disease Control and Prevention estimates that far more mild traumatic brain injuries may occur each year in the United States but the true number is unknown because only injuries severe enough to bring someone to an emergency room are counted.
Most of those who do show up at emergency rooms are treated and released without being admitted to the hospital. In general, most people with mild traumatic brain injuries recover fully, but about one in six go on to develop persistent, sometimes permanent, disability.
The problem, Manley said, is that there is no way to tell which patients are going to have the poor long-term outcomes. Some socioeconomic indicators can help predict prolonged disability, but until now there were no proven imaging features, or blood tests for predicting how well or how fast a patient will recover. Nor is there a consensus on how to treat mild traumatic brain injuries.
“The treatment’s all over the place – if you’re getting treatment at all,” Manley said.
The new work is an important step toward defining a more quantitative way of assessing patients with mild traumatic brain injuries and developing more precision medical tools to detect, monitor and treat them, he added.
If doctors knew which patients were at risk of greater disabilities, they could be followed more closely. Being able to identify patients at risk of long-term consequences would also speed the development of new therapeutics because it would allow doctors to identify patients who would benefit the most from treatment and improve their ability to test potential new drugs in clinical trials.
Brain-Removal Tool Left in Mummy’s Skull
A brain-removal tool used by ancient Egyptian embalmers has been discovered lodged in the skull of a female mummy that dates back around 2,400 years. Removal of the brain was an Egyptian mummification procedure that became popular around 3,500 years ago and remained in use in later periods. Identifying the ancient tools embalmers used for brain removal is difficult, and researchers note this is only the second time that such a tool has been reported within a mummy’s skull.
The discovery
Located between the left parietal bone and the back of the skull, which had been filled with resin, the object was discovered in 2008 through a series of CT scans. Researchers then inserted an endoscope (a thin tube often used for noninvasive medical procedures) into the mummy to get a closer look and ultimately detach it from resin to which it had gotten stuck.
"We cut it with a clamp through the endoscope and then removed it from the skull," said lead researcher Dr. Mislav Čavka, of the University Hospital Dubrava in Zagreb Croatia, in an interview with LiveScience.
They found themselves peering at an object more than 3 inches (8 centimeters) long that would have been used for liquefying and removing the brain. “It almost definitely would have been used in excerebration [brain removal] of the mummy,” Čavka said.
The instrument would have been inserted through a hole punched into the ethmoid bone near the nose. “Some parts [of the brain] would be wrapped around this stick and pulled out, and the other parts would be liquefied,” Čavka said.
The Egyptian mummy could then be put on its abdomen and the liquid drained through the nose hole. “It is an error that [the] embalmers left this stick in the skull,” said Čavka, adding the tool may have broken apart during the procedure.
This embalming accident, unfortunate for the ancient mummy, has provided researchers with a very rare artifact. Čavka’s team point out in a paper they published recently in the journal RSNA RadioGraphics the only other brain-removal stick found inside a mummy’s skull dates back 2,200 years.
New insights
The stick is quite brittle and the team could not do as thorough of an analysis as they’d hoped. Looking at it under a microscope, botanical experts determined the tool is made from plants in the group Monocotyledon, which includes forms of palm and bamboo.
The most curious find came when the researchers compared their discovery with an ancient account of brain removal made by the Greek writer Herodotus in the fifth century B.C. A visitor to Egypt, he had this to say about how Egyptian brain removal worked (as translated by A. D. Godley, Cambridge, Harvard University Press, 1920, through Perseus Digital Library):
"Having agreed on a price, the bearers go away, and the workmen, left alone in their place, embalm the body. If they do this in the most perfect way, they first draw out part of the brain through the nostrils with an iron hook, and inject certain drugs into the rest."
The recent discovery suggests an organic stick, not an “iron hook,” was used in at least some of these procedures, possibly for economic reasons. Researchers note that the tool found in the skull of the other mummy, dating from 2,200 years ago, was also made of an organic material.