Alveolar pulmonary edema showing the classical bat wing appearance, seen as perihilar fluffy opacities.
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Monday, March 14, 2005
Friday, March 11, 2005
Application of PET and PEt/CT imaging for cancer screening
Chen YK, Ding HJ, Su CT, Shen YY, Chen LK, Liao AC, Hung TZ, Hu FL, Kao CH
The aim of this study was to evaluate the potential application of 18-fluorodeoxyglucose positron emission tomography (FDG PET) and PET/CT for cancer screening in asymptomatic individuals. The subjects consisted of 3631 physical check-up examinees (1947 men, 1684 women; mean age +/- SD, 52.1 +/- 8.2 y) with non-specific medical histories. Whole-body FDG PET (or PET/CT), ultrasound and tumor markers were performed on all patients. Focal hypermetabolic areas with intensities equal to or exceeding the level of FDG uptake in the brain were considered abnormal and interpreted as neoplasia. Follow-up periods were longer than one year. Among the 3631 FDG PET (including 1687 PET/CT), ultrasound and tumor markers examinations, malignant tumors were discovered in 47 examinees (1.29%). PET findings were true-positive in 38 of the 47 cancers (80.9%). In addition, 32 of the 47 cancers were screened with the PET/CT scan. PET detected cancer lesions in 28 of the 32 examinees. However, the CT detected cancer lesions in only 15 out of 32 examinees. The sensitivity of FDG PET in the detection of a wide variety of cancers is high. Most cancer can be detected with FDG PET at a resectable stage. CT of the PET/CT for localization and characteristics of the lesion showed an increased specificity of the PET scan. The use of ultrasound and tumor markers may complement the PET scan in cancer screening for hepatic and urologic neoplasms.
Anticancer Res. 2004 Nov-Dec;24(6):4103-8
Wednesday, March 9, 2005
King Tut's CT scan rules out violent death
But test results provide little insight into how he died
King Tut wasn't murdered by a blow to the head, nor was his chest crushed in an accident. But after ruling out those long-time theories, the most revealing tests ever performed on the boy pharaoh's mummy didn't solve the mystery of how he died.
The results of the high-tech CT scan released yesterday raised one new possibility: They suggested that just days before his death, Tutankhamen might have badly broken his left thigh, puncturing the skin -- an injury that could have caused a dangerous infection.
But not everyone on the Egyptian-led team that pored over 1,700 CT images of Tut's body taken two months ago agreed with that theory. Some said the fracture could have occurred from mishandling when the mummy was discovered in 1922 in Luxor's Valley of the Kings.
Zahi Hawass, head of Egypt's Supreme Council of Antiquities, said the study allowed him to rule out violent death, but left him with no idea how Tut died. He said further tests will try to determine whether Tut died from natural causes, or perhaps was poisoned, but he stressed that it is unlikely they will find an answer.
Still, the CT results provided the most revealing insight yet into the life of ancient Egypt's most famous king, who ruled 3,300 years ago.
Tutankhamen was a well-fed, healthy, yet slightly built 19-year-old, standing 5 feet 6 inches tall at the time of his death, the test suggests. It was the first time his age has been established.
He had the typical overbite characteristic of other kings from his family and a slight cleft palate, which did not cause a cleft lip or other facial deformities. He also had large incisor teeth and his lower teeth were slightly misaligned.
While much interest has surrounded Tut's life, most attention has focused on how he died. X-rays taken in 1968 by Liverpool University anatomists found bone fragments inside Tut's skull, suggesting he might have been slain by being hit on the head.
But Mr. Hawass said the CT scan, the first ever performed on an ancient Egyptian king, ruled that out.
"The team found no evidence for a blow to the back of the head, and no other indication of foul play," he said.
He suggested that the fragments came from royal funerary workers who drilled a hole into the skull to let embalmers pour resins and other fluids in to prepare the body for mummification.
Some on the CT-scan team, which included two Italian experts and one from Switzerland, speculated that damage to the skull and upper neck might have been caused by the archaeological team led by Briton Howard Carter when they removed the pharaoh's famous golden mask after discovering his tomb.
Mr. Hawass said the team discounted a theory that the absence of Tut's sternum and most of his front ribs indicated a traumatic death.
"They also found it extremely unlikely that he suffered an accident in which he crushed his chest," he said, adding that such an injury would have caused damage elsewhere in the body, such as the spine, and the team saw none.
Mr. Hawass said he had no firm idea of how Tut died. But he offered two theories.
"He may have died from natural causes or was poisoned. We are going to look at his viscera to see if his organs show any signs, but it is virtually impossible to prove how he died," he said, giving no details on more tests or when they would be performed.
Mr. Hawass said Tut's death, around 1323 B.C., was surprising considering he was only 19, appeared to be healthy and suffered no infectious diseases or major childhood malnutrition.
"The mystery of his death will continue, but the case over whether he was [violently] murdered is closed," he said.
The CT scan, during which Tut's leather-like mummy was briefly removed from its tomb and placed into the scanner, did not address questions about Tut's precise royal lineage. It is unclear whether he was the son or a half brother of Akhenaten, the "heretic" pharaoh who introduced a revolutionary form of monotheism to ancient Egypt and was the son of Amenhotep III.
Mr. Hawass reiterated his refusal to allow DNA testing on Tut's remains, saying the science has a 40-per-cent chance for error when used on mummies.
"I believe these results will close the case of Tutankhamen, and the king will not need to be examined again," he said. "We cannot go again and open this mummy at all -- King Tut will rest forever."
http://www.theglobeandmail.com
King Tut wasn't murdered by a blow to the head, nor was his chest crushed in an accident. But after ruling out those long-time theories, the most revealing tests ever performed on the boy pharaoh's mummy didn't solve the mystery of how he died.
The results of the high-tech CT scan released yesterday raised one new possibility: They suggested that just days before his death, Tutankhamen might have badly broken his left thigh, puncturing the skin -- an injury that could have caused a dangerous infection.
But not everyone on the Egyptian-led team that pored over 1,700 CT images of Tut's body taken two months ago agreed with that theory. Some said the fracture could have occurred from mishandling when the mummy was discovered in 1922 in Luxor's Valley of the Kings.
Zahi Hawass, head of Egypt's Supreme Council of Antiquities, said the study allowed him to rule out violent death, but left him with no idea how Tut died. He said further tests will try to determine whether Tut died from natural causes, or perhaps was poisoned, but he stressed that it is unlikely they will find an answer.
Still, the CT results provided the most revealing insight yet into the life of ancient Egypt's most famous king, who ruled 3,300 years ago.
Tutankhamen was a well-fed, healthy, yet slightly built 19-year-old, standing 5 feet 6 inches tall at the time of his death, the test suggests. It was the first time his age has been established.
He had the typical overbite characteristic of other kings from his family and a slight cleft palate, which did not cause a cleft lip or other facial deformities. He also had large incisor teeth and his lower teeth were slightly misaligned.
While much interest has surrounded Tut's life, most attention has focused on how he died. X-rays taken in 1968 by Liverpool University anatomists found bone fragments inside Tut's skull, suggesting he might have been slain by being hit on the head.
But Mr. Hawass said the CT scan, the first ever performed on an ancient Egyptian king, ruled that out.
"The team found no evidence for a blow to the back of the head, and no other indication of foul play," he said.
He suggested that the fragments came from royal funerary workers who drilled a hole into the skull to let embalmers pour resins and other fluids in to prepare the body for mummification.
Some on the CT-scan team, which included two Italian experts and one from Switzerland, speculated that damage to the skull and upper neck might have been caused by the archaeological team led by Briton Howard Carter when they removed the pharaoh's famous golden mask after discovering his tomb.
Mr. Hawass said the team discounted a theory that the absence of Tut's sternum and most of his front ribs indicated a traumatic death.
"They also found it extremely unlikely that he suffered an accident in which he crushed his chest," he said, adding that such an injury would have caused damage elsewhere in the body, such as the spine, and the team saw none.
Mr. Hawass said he had no firm idea of how Tut died. But he offered two theories.
"He may have died from natural causes or was poisoned. We are going to look at his viscera to see if his organs show any signs, but it is virtually impossible to prove how he died," he said, giving no details on more tests or when they would be performed.
Mr. Hawass said Tut's death, around 1323 B.C., was surprising considering he was only 19, appeared to be healthy and suffered no infectious diseases or major childhood malnutrition.
"The mystery of his death will continue, but the case over whether he was [violently] murdered is closed," he said.
The CT scan, during which Tut's leather-like mummy was briefly removed from its tomb and placed into the scanner, did not address questions about Tut's precise royal lineage. It is unclear whether he was the son or a half brother of Akhenaten, the "heretic" pharaoh who introduced a revolutionary form of monotheism to ancient Egypt and was the son of Amenhotep III.
Mr. Hawass reiterated his refusal to allow DNA testing on Tut's remains, saying the science has a 40-per-cent chance for error when used on mummies.
"I believe these results will close the case of Tutankhamen, and the king will not need to be examined again," he said. "We cannot go again and open this mummy at all -- King Tut will rest forever."
http://www.theglobeandmail.com
Monday, March 7, 2005
Safety concerns of 3-Tesla MR scanners
Safety Considerations of 3T MR Scanners
Obviously, the safety issues involve the stronger magnetic field of the 3T system. The most conspicuous concern is the static magnetic field strength and the so-called projectile effect.
True, some guidelines for the MR environment remain the same with the stronger magnets. “Guidelines for general behavior in the MR environment, as far as watching out for strong static fields, will be the same for new systems and systems currently being used. This is especially true for the projectile effect, where ferromagnetic objects close to the static magnetic field can become dangerous projectiles that could injure or kill anyone between the object and the magnet. A 1.5T magnet has 30,000 times the strength of the earth’s magnetic field, while a 3T magnet has the force of 60,000 times the strength. When you reach forces of that level, it’s difficult to draw a line marking the point at which an object becomes a harmful projectile. How much more lethal would an unsecured oxygen tank become in the presence of a 3T system than near a 1.5T system?
True, some guidelines for the MR environment remain the same with the stronger magnets. “Guidelines for general behavior in the MR environment, as far as watching out for strong static fields, will be the same for new systems and systems currently being used. This is especially true for the projectile effect, where ferromagnetic objects close to the static magnetic field can become dangerous projectiles that could injure or kill anyone between the object and the magnet. A 1.5T magnet has 30,000 times the strength of the earth’s magnetic field, while a 3T magnet has the force of 60,000 times the strength. When you reach forces of that level, it’s difficult to draw a line marking the point at which an object becomes a harmful projectile. How much more lethal would an unsecured oxygen tank become in the presence of a 3T system than near a 1.5T system?
Magnetic Field Effects
The most considerable concerns involve the effect of the magnetic field on medical devices and implants. Some medical devices are safe and compatible at 1.5 but not at 3T. A metallic device with weak ferromagnetic qualities in relation to a 1.5 system may experience significant magnetic field interaction at 3T.
Problems presented by 3T for metallic implants include translational attraction and torque. Translational attraction is essentially the projectile effect, when an object moves sideways toward a magnet. By comparison, torque, as it relates to MRI, refers to the shifting or twisting of ferromagnetic medical devices and implants inside the patient’s body. The movement is caused by the static magnetic field and can cause discomfort or injury if an implant is displaced. It can even cause death if the movement involves a life-sustaining device. Most reported cases of MR-related injuries and the few fatalities that have occurred have apparently been the result of failure to follow safety guidelines or of use of inappropriate or outdated information related to the safety aspects of biomedical implants and devices. To prevent accidents in the MR environment, therefore, it is necessary to revise information on biologic effects and safety according to changes that have occurred in MR technology and with regard to current guidelines for biomedical implants and devices.
In the study, which was published in the March 2003 issue of the American Journal of Neuroradiology (“Aneurysm Clips: Evaluation of Magnetic Field Interactions and Translational Attraction by Use of ‘Long-Bore’ and ‘Short-Bore’ 3.0-T MR Imaging Systems,” [Shellock, Jean A. Tkach, Paul M. Ruggieri, Thomas J. Masaryk, and Peter A. Rasmussen]), the researchers evaluated magnetic field interactions for 32 aneurysm clips in association with exposure to “long-bore” and “short-bore” 3T MR systems.Each clip was quantitatively assessed for translational attraction and qualitatively evaluated for torque. The researchers found that 17 of the 32 aneurysm clips showed positive magnetic field interactions. Specifically, 15 aneurysm clips made from commercially pure titanium and titanium alloy displayed no translational attraction, while 17 clips made from stainless steel alloy, Phynox, and Elgiloy displayed positive deflection angles. According to the researchers, the 32 different aneurysm clips passed the deflection angle test by using the long- and short-bore 3T MRI systems, which indicated that they are safe for patients and other persons in MR environments. However, the authors write, only clips made from the titanium and titanium alloy are entirely safe for patients undergoing MR imaging procedures because of the total lack of magnetic field interactions. The remaining clips require characterization of magnetic interactions.
Problems presented by 3T for metallic implants include translational attraction and torque. Translational attraction is essentially the projectile effect, when an object moves sideways toward a magnet. By comparison, torque, as it relates to MRI, refers to the shifting or twisting of ferromagnetic medical devices and implants inside the patient’s body. The movement is caused by the static magnetic field and can cause discomfort or injury if an implant is displaced. It can even cause death if the movement involves a life-sustaining device. Most reported cases of MR-related injuries and the few fatalities that have occurred have apparently been the result of failure to follow safety guidelines or of use of inappropriate or outdated information related to the safety aspects of biomedical implants and devices. To prevent accidents in the MR environment, therefore, it is necessary to revise information on biologic effects and safety according to changes that have occurred in MR technology and with regard to current guidelines for biomedical implants and devices.
In the study, which was published in the March 2003 issue of the American Journal of Neuroradiology (“Aneurysm Clips: Evaluation of Magnetic Field Interactions and Translational Attraction by Use of ‘Long-Bore’ and ‘Short-Bore’ 3.0-T MR Imaging Systems,” [Shellock, Jean A. Tkach, Paul M. Ruggieri, Thomas J. Masaryk, and Peter A. Rasmussen]), the researchers evaluated magnetic field interactions for 32 aneurysm clips in association with exposure to “long-bore” and “short-bore” 3T MR systems.Each clip was quantitatively assessed for translational attraction and qualitatively evaluated for torque. The researchers found that 17 of the 32 aneurysm clips showed positive magnetic field interactions. Specifically, 15 aneurysm clips made from commercially pure titanium and titanium alloy displayed no translational attraction, while 17 clips made from stainless steel alloy, Phynox, and Elgiloy displayed positive deflection angles. According to the researchers, the 32 different aneurysm clips passed the deflection angle test by using the long- and short-bore 3T MRI systems, which indicated that they are safe for patients and other persons in MR environments. However, the authors write, only clips made from the titanium and titanium alloy are entirely safe for patients undergoing MR imaging procedures because of the total lack of magnetic field interactions. The remaining clips require characterization of magnetic interactions.
Greater Heat Potential
Other crucial elements of safety are radiofrequency (RF), heat, and the specific absorption rate. RF energy pulses are used in every MR system to generate the signal measured during each scan. The absorption of RF power into the body causes heating of the tissue. Unregulated absorption can lead to injury.
Sunday, March 6, 2005
Journal Club-High-resolution sonography of the rib: can fracture and metastasis be differentiated?
Paik SH, Chung MJ, Park JS, Goo JM, Im JG.Department of Radiology, Soonchunhyang University, Bucheon Hospital, Gyeonggido, Korea.
OBJECTIVE: Our aim was to evaluate whether high-resolution sonography can provide additional information concerning rib lesions compared with radiography or bone scintigraphy.
MATERIALS AND METHODS: Fifty-eight patients with high-uptake rib lesions seen on bone scintigraphy were selected. Radiography and rib high-resolution sonography were performed on these patients. High-resolution sonography was performed using a linear 5-12 MHz transducer. By means of clinical history, histopathologic examination, and follow-up observation, these patients were classified into rib fracture (n = 37), rib metastasis (n = 18), or unknown (n = 3) groups. High-resolution sonography images of the 55 proven cases were reviewed for the presence of five representative findings: cortical disruption, callus formation, cortical deformity, mass, or bone destruction. The frequencies of these findings were compared between the groups with fracture and metastasis.
RESULTS: Rib lesions were matched by bone scintigraphy and high-resolution sonography in 53 (96%) of 55 patients and by bone scintigraphy and plain radiography in 23 (42%) of 55 patients. High-resolution sonography revealed 17 (94%) of 18 patients with metastasis and 36 (97%) of 37 patients with rib fractures. Metastatic lesions were seen as mass formation (n = 13) and irregular bone destruction (n = 7) on high-resolution sonography. Fracture was seen as cortical disruption with or without hematoma (n = 17), callus formation (n = 9), or cortical deformity, such as angling or stepping (n = 12).
CONCLUSION: High-resolution sonography of the ribs is a useful method of characterizing rib lesions in patients who have hot-uptake lesions on bone scintigraphy.
AJR Am J Roentgenol. 2005 Mar;184(3):969-74
OBJECTIVE: Our aim was to evaluate whether high-resolution sonography can provide additional information concerning rib lesions compared with radiography or bone scintigraphy.
MATERIALS AND METHODS: Fifty-eight patients with high-uptake rib lesions seen on bone scintigraphy were selected. Radiography and rib high-resolution sonography were performed on these patients. High-resolution sonography was performed using a linear 5-12 MHz transducer. By means of clinical history, histopathologic examination, and follow-up observation, these patients were classified into rib fracture (n = 37), rib metastasis (n = 18), or unknown (n = 3) groups. High-resolution sonography images of the 55 proven cases were reviewed for the presence of five representative findings: cortical disruption, callus formation, cortical deformity, mass, or bone destruction. The frequencies of these findings were compared between the groups with fracture and metastasis.
RESULTS: Rib lesions were matched by bone scintigraphy and high-resolution sonography in 53 (96%) of 55 patients and by bone scintigraphy and plain radiography in 23 (42%) of 55 patients. High-resolution sonography revealed 17 (94%) of 18 patients with metastasis and 36 (97%) of 37 patients with rib fractures. Metastatic lesions were seen as mass formation (n = 13) and irregular bone destruction (n = 7) on high-resolution sonography. Fracture was seen as cortical disruption with or without hematoma (n = 17), callus formation (n = 9), or cortical deformity, such as angling or stepping (n = 12).
CONCLUSION: High-resolution sonography of the ribs is a useful method of characterizing rib lesions in patients who have hot-uptake lesions on bone scintigraphy.
AJR Am J Roentgenol. 2005 Mar;184(3):969-74
Wednesday, March 2, 2005
Bone Age assessment with ultrasound device.
Assessment of skeletal age at the wrist in children with a new ultrasound device.
Mentzel HJ, Vilser C, Eulenstein M, Schwartz T, Vogt S, Bottcher J, Yaniv I, Tsoref L, Kauf E, Kaiser WA.
Background: Determination of skeletal development in children is important. The most common method of evaluation uses the standards of Greulich and Pyle (G&P) to assess the left hand radiograph. Numerous assessments may be made during follow-up.
Objective: The aim of our study was to compare the accuracy of a new sonographic method with the standard radiographic method. Materials and methods: Seventy consecutive patients (age 6-17 years; 34 girls, 36 boys) underwent radiography of the left hand, followed by sonographic examination of the same hand using the BonAge system (Sunlight Medical Ltd., Israel). This system evaluates the relationship between the velocity of sound passing thorough the distal radial and ulna epiphysis and growth, using gender- and ethnicity-based algorithms. One experienced paediatric radiologist analysed the radiograph and assigned bone age scores based on the G&P atlas for the whole left hand and for the distal radius alone. The radiologist was blinded to the chronological age (CA), height of the patient and the BonAge result. Correlation between BonAge and G&P was undertaken.
Results: In 65 patients, BonAge measurement could be performed successfully. In five patients, the scanning process was impossible using the ultrasound device. The r(2) (r is the Pearson correlation coefficient) of the BonAge ultrasound measurement and the G&P method was 0.82. The averaged accuracy (i.e. absolute difference in years between G&P reading and BonAge ultrasonic results) was calculated. Results were similar for boys and girls: 1.0+/-0.8 years for the whole left hand and 0.8+/-0.7 year for the distal radius. On average, the difference between BonAge and CA is the same as the difference between G&P and CA, i.e. 1.4 years.
Conclusions: The BonAge device demonstrates the ability of ultrasound to produce an accurate assessment of bone age. The results are highly correlated with skeletal age evaluated conventionally using the G&P method. Obvious advantages of the ultrasound device are objectivity, lack of ionizing radiation, and easy accessibility.
Pediatr Radiol. 2005 Feb 24; [Epub ahead of print]
Mentzel HJ, Vilser C, Eulenstein M, Schwartz T, Vogt S, Bottcher J, Yaniv I, Tsoref L, Kauf E, Kaiser WA.
Background: Determination of skeletal development in children is important. The most common method of evaluation uses the standards of Greulich and Pyle (G&P) to assess the left hand radiograph. Numerous assessments may be made during follow-up.
Objective: The aim of our study was to compare the accuracy of a new sonographic method with the standard radiographic method. Materials and methods: Seventy consecutive patients (age 6-17 years; 34 girls, 36 boys) underwent radiography of the left hand, followed by sonographic examination of the same hand using the BonAge system (Sunlight Medical Ltd., Israel). This system evaluates the relationship between the velocity of sound passing thorough the distal radial and ulna epiphysis and growth, using gender- and ethnicity-based algorithms. One experienced paediatric radiologist analysed the radiograph and assigned bone age scores based on the G&P atlas for the whole left hand and for the distal radius alone. The radiologist was blinded to the chronological age (CA), height of the patient and the BonAge result. Correlation between BonAge and G&P was undertaken.
Results: In 65 patients, BonAge measurement could be performed successfully. In five patients, the scanning process was impossible using the ultrasound device. The r(2) (r is the Pearson correlation coefficient) of the BonAge ultrasound measurement and the G&P method was 0.82. The averaged accuracy (i.e. absolute difference in years between G&P reading and BonAge ultrasonic results) was calculated. Results were similar for boys and girls: 1.0+/-0.8 years for the whole left hand and 0.8+/-0.7 year for the distal radius. On average, the difference between BonAge and CA is the same as the difference between G&P and CA, i.e. 1.4 years.
Conclusions: The BonAge device demonstrates the ability of ultrasound to produce an accurate assessment of bone age. The results are highly correlated with skeletal age evaluated conventionally using the G&P method. Obvious advantages of the ultrasound device are objectivity, lack of ionizing radiation, and easy accessibility.
Pediatr Radiol. 2005 Feb 24; [Epub ahead of print]
Image Case
Antenatal diagnosis of esophageal atresia- a case showing polyhydramnios, absent stomach bubble and a pouch like dilatation of cervical esophagus.
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