[Imaging in children and adolescents with urinary tract infections]. / Bildgebung bei Harnwegsinfektionen im Kindes- und Jugendalter.

CLINICAL/METHODOLOGICAL PROBLEM: Urinary tract infections are among the most common infectious diseases in childhood. The task of imaging is to detect predisposing factors, such as urinary transport disorders, vesicoureteral reflux, as well as complications such as abscesses or pyonephrosis in addition to possible morphological changes of the kidneys and the draining urinary tract during an infection. STANDARD RADIOLOGICAL PROCEDURES: The initial diagnostic imaging technique is generally sonography. For the diagnosis of vesicoureteral reflux, voiding urosonography or alternatively radiological voiding cystourethrography are used. Further diagnostic workup may include scintigraphy, magnetic resonance imaging (MRI) or, in exceptional cases, computed tomography (CT). RECOMMENDATION FOR PRACTICE: In children and adolescents, it is of particular importance to avoid recurrent urinary tract infections and their sequelae. This requires precise imaging diagnostics, which must be performed with special consideration of radiation protection.

[Comparison of MRI and CT for assessment of childhood fractures: studies on a porcine model]. / Vergleich von MRT und CT bei Frakturen im Kindesalter: Untersuchungen an einem Schweinemodell.

BACKGROUND: The purpose of this study was to evaluate the capacity of MRI to achieve a diagnostic accuracy in pediatric fracture diagnosis comparable to CT. MATERIAL AND METHODS: In an ex vivo study design, simulating pediatric skeletal trauma, 248 limb bones of 9 dead young pigs with intact soft tissue were fractured. The samples were examined in a 1.5 T MRI with T1-weighted SE sequences. A standard scanning protocol was chosen for 64 multislice CT. CT results served as the reference standard. RESULTS: A total of 168 fractures were found. Seven fractures were missed by MRI, whereas another six ones were detected solely by MRI. The fracture type was the same in 137, partially the same in 12, and different in 6 cases. The dislocation was the same in 137, partially the same in 13, and different in 5 fractures. All differences were not statistically significant. CONCLUSION: MRI has a diagnostic accuracy in fracture diagnosis comparable to CT. Therefore, protocols of traumatology in infancy should be revised.

[Pediatric fracture diagnosis--ultra-low-dose CT with an effective dose equal to that of radiographs]. / Pädiatrische Frakturdiagnostik--Ultra-low-dose-CT mit der effektiven Dosis von Röntgenaufnahmen.

PURPOSE: Computed tomography (CT) plays an important role in trauma diagnosis in children, especially for complex fractures. The aim of this study was to examine the diagnostic value of ultra-low-dose-CT (ULD-CT) with an effective dose equal to that of radiographs in an experimental study and to compare its results with those of radiographs. MATERIALS AND METHODS: Limb bones of dead young pigs served as a model for pediatric bones. A total of 51 fractured and non-fractured bones were examined with a 64 multislice-CT with a standard dose protocol as gold standard, with two ultra-low-dose-protocols, and with standard radiographs with different exposures. RESULTS: In spite of high background noise the examinations of ULD-CT were not adequate only in 2 of 204 cases. ULD-CT was slightly superior to radiographs in detection of fractures. ULD-CT could significantly better characterize the fractures than radiographs. The overall result of ULD-CT was significantly better than that of radiographs with standard exposure. CONCLUSION: ULD-CT with the effective dose of radiographs is successfully applicable in pediatric fracture diagnosis, and its overall result is significantly better than that of radiographs.

Application of time-of-flight aerosol mass spectrometry for the online measurement of gaseous molecular iodine.

Here we present a new application of a time-of-flight aerosol mass spectrometer (TOF-AMS) for the measurement of atmospheric trace gases in real-time. Usually, TOF-AMS instruments are not sensitive to gas-phase species due to the aerodynamic particle focusing inlet system which reduces the gas phase species by a factor of about 10(7) relative to the particle phase. This efficient removal of the gas phase and the resulting high relative enrichment of particles is one reason for the very high sensitivity of TOF-AMS instruments for particle phase compounds (detection limits in the sub-µg/m(3)-range for online measurements with 1 min integration time), which allows application of the instruments even under clean atmospheric conditions. Here we use artificially generated particles as sampling probes to transfer selected atmospheric trace gases into the particle phase before entering the AMS (gaseous compound trapping in artificially generated particles-AMS, GTRAP-AMS). The sampling probe particles are mixed with the gaseous analytes upstream of the TOF-AMS in a 0.5 L flow tube. As an exemplary application of the method, the measurement of trace levels of gaseous molecular iodine is demonstrated. α-Cyclodextrin (α-CD/NH(4)Br) particles are used as selective sampling probes to transfer molecular iodine into the AMS. A detection limit in the subparts-per-billion (sub-ppb) range was achieved. The method was compared to a recently developed off-line method that combines denuder sampling of gaseous I(2) and gas chromatography/mass spectrometry (GC/MS) analysis. To demonstrate the usability of the method, temporally resolved I(2) emission profiles from a brown algae species (Laminaria saccharina) under exposure of ambient ozone levels were investigated. Total I(2) release rates of 36.5 pmol min(-1) grams fresh weight (gFW)(-1) at 100 pbb O(3) and 33.4 pmol min(-1) gFW(-1) at 50 ppb O(3) were obtained within the first hour of ozone exposure.

[Is ultrasound equal to X-ray in pediatric fracture diagnosis?]. / Ist die Sonografie der Röntgendiagnostik in der pädiatrischen Frakturdiagnostik gleichwertig?

PURPOSE: Ultrasound is currently not established for the diagnosis of fractures. The aim of this study was to compare ultrasound and X-ray beyond their use solely for the identification of fractures, i. e., for the detection of fracture type and dislocation for pediatric fracture diagnosis. MATERIALS AND METHODS: Limb bones of dead young pigs served as a model for pediatric bones. The fractured bones were examined with ultrasound, X-ray, and CT, which served as the gold standard. RESULTS: 162 of 248 bones were fractured. 130 fractures were identified using ultrasound, and 148 using X-ray. There were some advantages of X-ray over ultrasound in the detection of fracture type (80 correct results using X-ray, 66 correct results using ultrasound). Ultrasound, however, was superior to X-ray for dislocation identification (41 correct results using X-ray, 51 correct results using ultrasound). Both findings were not statistically significant after adjustment for multiple testing. CONCLUSION: Ultrasound not only has comparable sensitivity to that of X-ray for the identification of limb fractures but is also equally effective for the diagnosis of fracture type and dislocation. Thus, ultrasound can be used as an adequate alternative method to X-ray for pediatric fracture diagnosis.

Ultrasound in diagnosis of fractures in children: unnecessary harassment or useful addition to X-ray?

PURPOSE: Handling children with trauma is often very difficult, as the signs and the exact location of the fracture are sometimes unclear. The aim of this study was to compare ultrasound and X-ray for the identification of fractures. MATERIALS AND METHODS: In this study 653 patients from newborn to 17 years old (mean age 4.4 years) with nonspecific clinical signs or clinically indistinct fracture location were examined initially with ultrasound. After identification of the fracture by ultrasound, an X-ray exam of the predefined region followed. In cases of negative ultrasound an X-ray exam was performed not focused on a predefined region. RESULTS: Examinations of 726 parts of the body revealed 308 fractures. 266 fractures were identified by both ultrasound and X-ray, 20 exclusively by ultrasound, 21 exclusively by X-ray. One maxillary fracture was missed. The sensitivity was 92.9% for ultrasound and 93.2% for X-ray, and the specificity was 99.5% (ultrasound) and 99.8% (X-ray). Ultrasound was superior to X-ray on the clavicle, but the opposite was true in the lower limb. In 8.4% of the patients ultrasound helped us to reduce the number of X-rays. CONCLUSION: Ultrasound is comparable to X-ray for the detection of fractures. Ultrasound should be the first imaging method in children with trauma and nonspecific clinical signs or indistinct location of pain, followed by X-ray exams of the predefined region.

[Assessment of bone density in children and adolescents by quantitative CT of one lumbar vertebra only]. / Messung der Knochendichte bei Kindern und Jugendlichen mittels quantitativer CT an nur einem Lendenwirbelkörper.

AIM: The aim of this study was to determine whether measuring the trabecular bone density in one lumbar vertebra (L) instead of three has an effect on the assessment of bone density in children. MATERIALS AND METHODS: Bone density was measured in 70 patients (38 male, 32 female), ages 1 to 22 years (mean age 12.4, median 13 years) using a Somatom Balance Scanner (Siemens). The trabecular bone density was measured (1-cm slice, 80 kV, 81 mAs) in L1 through L3. RESULTS: The mean bone density in the lumbar vertebrae was 139.9 mg/ml calcium-hydroxylapatite per ml bone in L1, 133.9 in L2, and 131.7 in L3, and the mean of all three vertebrae was 135.2 mg/ml. Measurements in L1 were 4.7 mg/ml (standard deviation [SD] 4.7 mg/ml) above the mean value of the three upper lumbar vertebrae. The density in L2 was 1.3 mg/ml below the mean (SD 3.1 mg/ml). On average, L3 was 3.5 mg/ml below the mean (SD 4.6 mg/ml). This minor systematic deviation in the measurement values for the individual vertebrae from the mean value was so low that there was no statistical evidence for a deviation from an ideal regression line. CONCLUSIONS: When using an adequate technique, especially accurate analysis of the topogram (scout view) and the tomogram, measurement of the bone density of one lumbar vertebra provides satisfactory information regarding the trabecular bone density in children, but the values differ in the three upper lumbar vertebrae. The bone density of L2 is close to the mean of the upper three vertebrae. In the case of pathologic values or a pathologic trabecular pattern, three vertebrae should be measured.

[Small bowel intussusception in childhood]. / Dünndarminvaginationen im Kindesalter: Diagnostik und Bedeutung.

BACKGROUND: Intussusception is the most common cause of abdominal emergency in early childhood. The majority of cases are ileocolic type of intussusception. Only few reports concerning small bowel intussusception have been reported. PATIENTS AND METHOD: We retrospectively reviewed the clinical records and imaging findings of all patients with the diagnosis of intussusception (comparing small bowel intussusception with ileocolic type of intussusception), which were documented by ultrasound in the period April 1997 to January 2001. The routine ultrasound scans included an evaluation of the entire abdomen using sector and linear transducers of high frequency (5 - 7.5 MHz) and power doppler ultrasound. RESULTS: A total of 22 patients with small bowel intussusception (9 female, 13 male) and 29 patients diagnosed to suffer from ileocolic intussusception (10 female, 19 male) were identified and treated. Children with small bowel intussusception were significant older in comparison to children with ileocolic type of intussusception (median age 50 vs. 11 months). In our series the presenting symptoms of patients with small bowel intussusception consisted of abdominal pain (86 %) and vomiting (36 %). The initial clinical symptoms of patients with ileocolic intussusception were abdominal pain (100 %), vomiting (72 %) and/or rectal fresh blood (35 %). Small bowel intussusception was an incidental finding in 3 asymptomatic patients (14 %). Hydrostatic reduction was attempted in 14 % of children with small bowel intussusception (vs. 93 % of children with ileocolic intussusception), one patient needed operative treatment (vs. 21 %). Outcome in all patients was favorable. CONCLUSION: The high percentage of patients with small bowel intussusception observed may relate to increased use of abdominal ultrasound in children presenting with abdominal pain and improvements in resolution and quality of the images. Small bowel intussusceptions in our series were in the majority of cases short-segmented, self-limited and without a lead point. In comparison to patients with ileocolic intussusception the presenting symptoms of small bowel intussusception are less acute.

Esophageal foreign bodies: removal of the new euro coins with a magnet tube.

AIM OF THIS STUDY: We use a magnet tube to extract esophageal coins. It is smaller than the Foley balloon catheter and easier to handle than a forceps. We present the magnet tube maneuver and investigate whether the new euro coins can be removed with a magnet. METHOD: We take radiographs of coins and measure the adhesive force of the magnet and compare with the 10 Pfennig German coin which we most often removed successfully from the esophagus. RESULTS: The 1, 2, and 5 euro cent pieces are magnetic and can possibly be removed with a magnet tube. The non-magnetic pieces can be identified based on the rim and size. DISCUSSION: When an esophageal foreign body is not round and smooth like a coin, the fluoroscopic guided procedure becomes more risky with respect to mucosal injury. When a large object is stuck in the esophagus for more than 24 hours, an endoscopy must be considered to rule out any severe damage to the esophageal wall.

Contrast-enhanced color Doppler sonography for evaluation of enlarged cervical lymph nodes in head and neck tumors.

OBJECTIVE: We determined whether contrast-enhanced color Doppler sonography can differentiate benign from malignant enlarged cervical lymph nodes in head and neck tumors. SUBJECTS AND METHODS: Ninety-four enlarged lymph nodes in 39 adult patients (32 men and seven women; age range, 30-81 years) were examined with B-mode sonography and with unenhanced and contrast-enhanced color Doppler sonography. All patients had carcinoma of the oral cavity. Histologically, lymphadenitis was found in 57 nodes and metastases in 37 nodes. Geometric dimension, texture, and margin of the node and detection and location of vessels were noted. Histology and imaging findings were correlated. RESULTS: The transverse-to-longitudinal diameter ratio in combination with texture and margin analysis resulted in a correct diagnosis in only approximately 79% of the nodes. With contrast-enhanced color Doppler sonography, 86% of nodes showed vessels, and 28% of nodes showed vessels with this technique exclusively. Characteristic configurations were identified: hilar vessels with branching indicated lymphadenitis (sensitivity, 98%; specificity, 100%), and predominantly peripheral vessels indicated metastases (100%, 98%). These findings changed the diagnosis in 13 nodes, changed the therapy in four patients, and led to an incorrect diagnosis in one patient. CONCLUSION: Enlarged lymph nodes can be characterized as metastatic or inflammatory with high diagnostic accuracy on the basis of their vascular architecture as seen on contrast-enhanced color Doppler sonography.

Role of high magnification specimen radiography in surgical and core biopsies of the breast.

The clinical relevance of a high magnification specimen radiography (HMSR) system in breast biopsies was evaluated and compared with conventional specimen radiography with a mammography system (SRM). 100 surgical biopsies of 72 patients and 248 core biopsies of 30 patients were examined in (a) maximal 20-fold HMSR in combination with storage phosphors and (b) 1.8-fold SRM using a film-screen system. Detection of calcifications/soft tissue lesions and the impact on management were evaluated. In surgical biopsies, SRM could detect only 22% of individual microcalcifications, 39% of calcified lesions and 67% of soft tissue lesions identified with HMSR. Calcifications down to 10 microns were identified with HMSR. In five biopsies, peripheral calcifications leading to additional resection were recognized only with HMSR; in three of these they were indicative of malignant tissue. In core biopsies, only 12% of individual microcalcifications seen with HMSR were identified with SRM. 52% and 16% of all cores were calcified on HMSR and SRM, respectively. Microcalcifications within cores were found only with HMSR in 41% of patients with calcified lesions. In conclusion, the better detectability of microcalcifications with HMSR led to justified additional tissue resections in surgical patients and reduced the number of core biopsies required in interventional patients.

Impaired osteoclastic bone resorption leads to osteopetrosis in cathepsin-K-deficient mice.

Cathepsin K is a recently identified lysosomal cysteine proteinase. It is abundant in osteoclasts, where it is believed to play a vital role in the resorption and remodeling of bone. Pycnodysostosis is a rare inherited osteochondrodysplasia that is caused by mutations of the cathepsin-K gene, characterized by osteosclerosis, short stature, and acroosteolysis of the distal phalanges. With a view to delineating the role of cathepsin K in bone resorption, we generated mice with a targeted disruption of this proteinase. Cathepsin-K-deficient mice survive and are fertile, but display an osteopetrotic phenotype with excessive trabeculation of the bone-marrow space. Cathepsin-K-deficient osteoclasts manifested a modified ultrastructural appearance: their resorptive surface was poorly defined with a broad demineralized matrix fringe containing undigested fine collagen fibrils; their ruffled borders lacked crystal-like inclusions, and they were devoid of collagen-fibril-containing cytoplasmic vacuoles. Assaying the resorptive activity of cathepsin-K-deficient osteoclasts in vitro revealed this function to be severely impaired, which supports the contention that cathepsin K is of major importance in bone remodeling.

New perspectives in head and neck sonography by signal-enhanced color Doppler sonography.

Ultrasound contrast agent is used in color Doppler flow imaging for signal enhancement in perfused vessels. We present our experience with its use in the head and neck area and the results obtained. Up until now, 30 patients with carcinomas of the oral cavity or the maxillary sinus, tumors of the mandible and metastatic or inflammatory lymph nodes have been examined. Conventional B-scan sonography was supplemented by non-contrast color Doppler flow imaging. Depending on the indication, 2.5 g Levovist in bolus or 4 g fractionated was injected intravenously in a concentration of 300 or 400 mg/ml. The administration of the contrast agent was tolerated by all patients without any side effects and in all cases led to a remarkable enhancement of the Doppler signals. About 15 to 30 s after injection, an enhancement in perfused vessels was detected. The fractioned injection of 4 g led to a lengthening of signal enhancement up to more than 10 min and to the possibility of examining more parts with a single application of contrast agent. In 64% of the lymph nodes, vessels could only be identified with the administration of Levovist. The general vessel topography could be better evaluated in 83% of the cases. The lymph-node-supplying vessels were identified in 8 of 11 patients after the injection of contrast media. Additional information, which was gained in 17 patients, increased the certainty of diagnosis or of the therapeutic concept. In three cases, the examinations with the signal enhancer resulted in a change in therapy. By applying signal enhancer in color Doppler sonography the fields of examination in the head and neck areas can be expanded.

MR imaging of mammographically detected clustered microcalcifications: is there any value?

PURPOSE: To assess the value of dynamic magnetic resonance (MR) imaging in patients with mammographically detected suspicious microcalcifications. MATERIALS AND METHODS: Sixty-three patients (age range, 31-84 years; mean age, 56 years) with mammographically suspicious clustered microcalcifications underwent dynamic MR imaging of the breast before surgical biopsy. MR imaging was performed with a 1.5-T unit and a two-dimensional fast low-angle shot sequence with a flip angle of 80 degrees. Thirty-two axial sections, 4 mm thick and without interval gaps, were acquired before and five times after administration of gadopentetate dimeglumine (dose, 0.1 mmol per kilogram of bodyweight). Histologic findings were used as the standard of reference. Any effect of MR imaging on surgical management was noted. RESULTS: Biopsy findings verified five patients with T1 invasive carcinomas, 33 with ductal carcinomas in situ, 13 with proliferative fibrocystic disease, eight with nonproliferative fibrocystic disease, and four with sclerosing adenosis. Contrast material-enhanced dynamic MR imaging had a sensitivity of 45%, a specificity of 72%, and an overall accuracy of 56% in differentiating benign from malignant microcalcifications. All invasive tumors were detected with MR imaging. In no case was surgical management altered by MR imaging findings. CONCLUSION: MR imaging of the breast is not reliable in differentiation of benign from malignant breast disease in mammographically suspicious clustered microcalcifications and has no effect on treatment.

[A new specimen radiography device with a maximum 20-fold magnification for breast diagnosis]. / Ein neues Präparatradiographiegerät mit maximal 20facher Vergrösserung für die Mammadiagnostik.

PURPOSE: A radiography system specially developed for specimen radiography and allowing maximal 20-fold magnification is presented. The efficiency of the system was tested and compared with that of conventional magnification mammography systems. METHODS: 23 surgical and 90 core biopsies of the breast were examined for detection of microcalcifications. As criteria the number of identifiable calcifications, their shape and configuration as well as tissue contrast were chosen. RESULTS: The new technique detected about 400% more microcalcifications, 200% more core and 50% more surgical biopsies containing calcifications. Thus, in a few cases, additional core biopsies were unnecessary. Moreover, this new system yielded additional information for the pathologist and surgeon concerning the exact localisation of suspicious lesions that facilitated working up specimens, or indicated additional surgical removal in special cases. CONCLUSIONS: By identification of malignant lesions not detectable with conventional magnification radiography systems, as well as a more exact localisation of suspicious lesions, false negative results may be reduced.

I-cell disease-like phenotype in mice deficient in mannose 6-phosphate receptors.

Mannose 6-phosphate receptor deficient mice were generated by crossing mice carrying null alleles for Igf2 and the 300 kDa and 46 kDa mannose 6-phosphate receptors, Mpr300 and Mpr46. Pre- and perinatal lethality of mice nullizygous for Igf2, Mpr300 and Mpr46 was increased. Triple deficient mice surviving the first postnatal day had normal viability and developed a phenotype resembling human I-cell disease. The triple deficient mice were characterized by dwarfism, facial dysplasia, waddling gait, dysostosis multiplex, elevated lysosomal enzymes in serum and histological signs of lysosomal storage predominantly in fibroblasts, but also in parenchymal cells of brain and liver. A paternally inherited Mpr300 wild type allele that is normally inactive in mice due to imprinting was reactivated in some tissues of mice lacking IGF II and MPR 46 and carrying a maternal Mpr300 null allele. Inspite of the partial reactivation the phenotype of these mice was similar to that of triple deficient mice.

New perspectives in head and neck sonography by signal-enhanced color Doppler sonography.

Ultrasound contrast agent is used in color Doppler flow imaging for signal enhancement in perfused vessels. We present our experience with its use in the head and neck area and the results obtained. Up until now, 30 patients with carcinomas of the oral cavity or the maxillary sinus, tumors of the mandible and metastatic or inflammatory lymph nodes have been examined. Conventional B-scan sonography was supplemented by non-contrast color Doppler flow imaging. Depending on the indication, 2.5 g Levovist in bolus or 4 g fractionated was injected intravenously in a concentration of 300 or 400 mg/ml. The administration of the contrast agent was tolerated by all patients without any side effects and in all cases led to a remarkable enhancement of the Doppler signals. About 15 to 30 s after injection, an enhancement in perfused vessels was detected. The fractioned injection of 4 g led to a lengthening of signal enhancement up to more than 10 min and to the possibility of examining more parts with a single application of contrast agent. In 64% of the lymph nodes, vessels could only be identified with the administration of Levovist. The general vessel topography could be better evaluated in 83% of the cases. The lymph-node-supplying vessels were identified in 8 of 11 patients after the injection of contrast media. Additional information, which was gained in 17 patients, increased the certainty of diagnosis or of the therapeutic concept. In three cases, the examinations with the signal enhancer resulted in a change in therapy. By applying signal enhancer in color Doppler sonography the fields of examination in the head and neck areas can be expanded.

A comparison of conventional mammographic magnification, ultra high magnification and industrial magnification radiography in the radiographic detection of microcalcifications within core biopsies of the breast.

The objective was to compare conventional magnification radiography (CMR), ultra high magnification radiography (UHMR) and industrial magnification radiography (IMR) in the detection of microcalcifications in breast core biopsies. 440 core biopsies were examined in 1.8-fold CMR and in 7-fold UHMR using a prototype unit. A subgroup of 59 core biopsies were also examined in 10-fold IMR. Number, size, and demarcation of microcalcifications, as well as tissue contrast, were evaluated. Only 67% of the microcalcifications seen with UHMR were detected by CMR and 78% of the core biopsies showing calcifications in UHMR were calcified in CMR. Only 38% and 58% of microcalcifications verified by IMR were identified by CMR and UHMR, respectively. 47% and 63% of the core biopsies showing calcifications in IMR were calcified in CMR and UHMR, respectively. Tissue contrast of IMR was superior to both other modalities. On the other hand, increased cost and time will probably prohibit the use of IMR for specimen radiography in routine clinical examinations. In conclusion, UHMR identifies substantially more core biopsies with microcalcifications than CMR, thus potentially reducing the number of core biopsies needed for histological analysis. IMR allowed the detection of approximately 50%/160% more microcalcifications than UHMR/CMR, thus rendering it the reference mode.

Microcalcifications in breast core biopsy specimens: disappearance at radiography after storage in formaldehyde.

PURPOSE: To determine whether radiographically proved calcifications in core biopsy specimens are better preserved in a nonaqueous fixative than in aqueous solutions. MATERIALS AND METHODS: One hundred fifty core biopsy specimens were taken from two female breast specimens that had been preserved in ethanol. Forty-one of the specimens with radiographically proved microcalcifications were divided into four groups and deposited in four different solutions: 10% formaldehyde, 0.9% sodium chloride, electrolyte solution, and 74.1% ethanol with 10% 2-propanol. The core specimens were radiographed again after 1 and 3 days. Five ethanol-preserved specimens were also reexamined radiographically after 2 weeks. RESULTS: Within 3 days, total radiographic disappearance of microcalcifications was observed in all core biopsy specimens that were immersed in solutions with high water content. In those core specimens preserved in ethanol, microcalcifications showed no change. CONCLUSION: A nonaqueous fixative, such as ethanol, is a better preservative of microcalcifications in breast core biopsy specimens than various aqueous solutions, possibly because calcium compounds are water-soluble.

Infrarenal abdominal aortic aneurysms: implications of CT evaluation of size and configuration for placement of endovascular aortic grafts.

PURPOSE: To measure infrarenal abdominal aortic aneurysms and assess the implications and potential obstacles for placement of an endovascular aortic graft undergoing clinical testing in Europe. MATERIALS AND METHODS: Helical computed tomography was used to measure 77 infrarenal aortic aneurysms (77 patients) and the distances between the aneurysms and the renal arteries and the aortic bifurcation. RESULTS: Mean length of the aneurysms was 8.2 cm; mean distance to the renal arteries, 2.7 cm; mean aortic diameter 1.5 cm distal to the renal arteries, 1.9 cm; and mean minimal diameter of perfused lumen, 2.5 cm. Thirteen aneurysms extended into the common iliac artery; 40 reached the bifurcation. The mean minimal luminal diameter of the iliac artery was 1.1 cm. CONCLUSION: Sufficient nonaneurysmal segments below the renal arteries and distal to the aneurysms are necessary for stent fixation. The large diameter of the delivery introducer in relation to the iliac arteries may be a major obstacle to graft delivery. At best, 33 patients could have benefited from use of the graft evaluated.