bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuronal processing of translational optic flow in the visual system of the shore crabCarcinus maenas
Authors: Horseman B. Geoff , Macauley Martin W. S. , Barnes W. Jon P.
Published: April 2011

This paper describes a search for neurones sensitive to optic flow in the visual system of the shore crab Carcinus maenas using a procedure developed from that of Krapp and Hengstenberg. This involved determining local motion sensitivity and its directional selectivity at many points within the neurone's receptive field and plotting the results on a map. Our results showed that local preferred directions of motion are independent of velocity, stimulus shape and type of motion (circular or linear). Global response maps thus clearly represent real properties of the neurones' receptive fields. Using this method, we have discovered two families of interneurones sensitive to translational optic flow. The first family has its terminal arborisations in the lobula of the optic lobe, the second family in the medulla. The response maps of the lobula neurones (which appear to be monostratified lobular giant neurones) show a clear focus of expansion centred on or just above the horizon, but at significantly different azimuth angles. Response maps such as these, consisting of patterns of movement vectors radiating from a pole, would be expected of neurones responding to self-motion in a particular direction. They would be stimulated when the crab moves towards the pole of the neurone's receptive field. The response maps of the medulla neurones show a focus of contraction, approximately centred on the horizon, but at significantly different azimuth angles. Such neurones would be stimulated when the crab walked away from the pole of the neurone's receptive field. We hypothesise that both the lobula and the medulla interneurones are representatives of arrays of cells, each of which would be optimally activated by self-motion in a different direction. The lobula neurones would be stimulated by the approaching scene and the medulla neurones by the receding scene. Neurones tuned to translational optic flow provide information on the three-dimensional layout of the environment and are thought to play a role in the judgment of heading.
Failure by fatigue in the field: a model of fatigue breakage for the macroalga Mazzaella, with validation
Authors: Mach Katharine J. , Tepler Sarah K. , Staaf Anton V. , Bohnhoff James C. , Denny Mark W.
Published: April 2011

Seaweeds inhabiting the extreme hydrodynamic environment of wave-swept shores break frequently. However, traditional biomechanical analyses, evaluating breakage due to the largest individual waves, have perennially underestimated rates of macroalgal breakage. Recent laboratory testing has established that some seaweeds fail by fatigue, accumulating damage over a series of force impositions. Failure by fatigue may thus account, in part, for the discrepancy between prior breakage predictions, based on individual not repeated wave forces, and reality. Nonetheless, the degree to which fatigue breaks seaweeds on wave-swept shores remains unknown. Here, we developed a model of fatigue breakage due to wave-induced forces for the macroalga Mazzaella flaccida. To test model performance, we made extensive measurements of M. flaccida breakage and of wave-induced velocities experienced by the macroalga. The fatigue-breakage model accounted for significantly more breakage than traditional prediction methods. For life history phases modeled most accurately, 105% (for female gametophytes) and 79% (for tetrasporophytes) of field-observed breakage was predicted, on average. When M. flaccida fronds displayed attributes such as temperature stress and substantial tattering, the fatigue-breakage model underestimated breakage, suggesting that these attributes weaken fronds and lead to more rapid breakage. Exposure to waves had the greatest influence on model performance. At the most wave-protected sites, the model underpredicted breakage, and at the most wave-exposed sites, it overpredicted breakage. Overall, our fatigue-breakage model strongly suggests that, in addition to occurring predictably in the laboratory, fatigue-induced breakage of M. flaccida occurs on wave-swept shores.
Avoidance of achromatic colours by bees provides a private niche for hummingbirds
Authors: Lunau Klaus , Papiorek Sarah , Eltz Thomas , Sazima Marlies
Published: April 2011

That hummingbird-pollinated plants predominantly have red flowers has been known for decades, but well-investigated research studies are still rare. Preference tests have shown that hummingbirds do not have an innate preference for red colours. In addition, hummingbirds do not depend solely upon red flowers, because white-flowered hummingbird-pollinated plants are also common and temporarily abundant. Here we show that both white and red hummingbird-pollinated flowers differ from bee-pollinated flowers in their reflection properties for ultraviolet (UV) light. Hummingbird-pollinated red flowers are on average less UV reflective, and white hummingbird-pollinated flowers are more UV reflective than the same coloured bee-pollinated ones. In preference tests with artificial flowers, neotropical orchid bees prefer red UV-reflecting artificial flowers and white UV-nonreflecting flowers over red and white flowers with the opposite UV properties. By contrast, hummingbirds showed no preference for any colour in the same tests. Plotting floral colours and test stimuli into the honeybees' perceptual colour space suggests that the less attractive colours are achromatic for bees and therefore more difficult to detect against the background. This underlying colour preference in bees might provide hummingbirds with a private niche that is not attractive to bees.
In vivo and in vitro assessment of cardiac β-adrenergic receptors in larval zebrafish (Danio rerio)
Authors: Steele Shelby L. , Yang Xiaodi , Debiais-Thibaud Mélanie , Schwerte Thorsten , Pelster Bernd , Ekker Marc , Tiberi Mario , Perry Steve F.
Published: April 2011

β-Adrenergic receptors (βARs) are crucial for maintaining the rate and force of cardiac muscle contraction in vertebrates. Zebrafish (Danio rerio) have one β1AR gene and two β2AR genes (β2aAR and β2bAR). We examined the roles of these receptors in larval zebrafish in vivo by assessing the impact of translational gene knockdown on cardiac function. Zebrafish larvae lacking β1AR expression by morpholino knockdown displayed lower heart rates than control fish, whereas larvae deficient in both β2aAR and β2bAR expression exhibited significantly higher heart rates than controls. These results suggested a potential inhibitory role for one or both β2AR genes. By using cultured HEK293 cells transfected with zebrafish βARs, we demonstrated that stimulation with adrenaline or procaterol (a β2AR agonist) resulted in an increase in intracellular cAMP levels in cells expressing any of the three zebrafish βARs. In comparison with its human βAR counterpart, zebrafish β2aAR expressed in HEK293 cells appeared to exhibit a unique binding affinity profile for adrenergic ligands. Specifically, zebrafish β2aAR had a high binding affinity for phenylephrine, a classical α-adrenergic receptor agonist. The zebrafish receptors also had distinct ligand binding affinities for adrenergic agonists when compared with human βARs in culture, with zebrafish β2aAR being distinct from human β2AR and zebrafish β2bAR. Overall, this study provides insight into the function and evolution of both fish and mammalian β-adrenergic receptors.
Physiology of invasion: cane toads are constrained by thermal effects on physiological mechanisms that support locomotor performance
Authors: Seebacher Frank , Franklin Craig E.
Published: April 2011

Understanding the mechanisms that constrain the invasiveness of introduced animals is essential for managing invasions and for predicting their limits. In most vertebrate species, the capacity for invasion relies upon the physiological systems that support locomotion, and oxygen transport and metabolism may become limiting as environmental temperatures increase as predicted by the oxygen limitation hypothesis. Here we test the oxygen limitation hypothesis and propose the alternative hypothesis that within-individual plasticity will compensate for thermal variation. We show that during exercise in the invasive cane toad (Rhinella marina) oxygen transport by the cardiovascular system was maximised in warm-acclimated toads at high (30°C) temperatures, and that oxygen content of arterial blood was not affected by temperature. Resting oxygen consumption remained stable across a 10°C temperature range (20–30°C) when toads were allowed to acclimate, so that there was no increase in resting oxygen demand that could lead to a decrease in aerobic scope at high temperatures. Additionally, temperature acclimation had no effect on arterial–venous differences in oxygen partial pressures. Toads relied more on glycolytic ATP production at low temperatures to support locomotor activity. Mitochondrial capacities (citrate synthase and cytochrome c oxidase activities) were greatest at warmer temperatures. Interestingly, the metabolic cost of exercise increased at low temperatures. In contradiction to predictions by the oxygen limitation hypothesis, aerobic performance was not limited by high temperatures. On the contrary, the relatively slow advance of cane toads to cooler climates can be explained by the constraints of low temperatures on the physiological systems supporting locomotion. It is likely that human-induced global warming will facilitate invasions of environments that are currently too cool to support cane toads.
Preparation of Thin-film Hydroxyapatite/Polymer Hybrids
Authors: Nishimura Tatsuya , Imai Hirotaka , Oaki Yuya , Sakamoto Takeshi , Kato Takashi
Published: April 2011

Thin-film hybrids of hydroxyapatite (HAP)/chitosan form in a supersaturated solution of HAP in the presence of poly(acrylic acid) (PAA). The cooperative interactions between chitosan, PAA, and calcium ion on the crystallization of calcium phosphate have been examined. In the presence of PAA, the crystallization of calcium phosphate occurs in the chitosan matrix, resulting in the formation of the hybrid thin films. Observation of the films by electron diffraction and X-ray diffraction confirm the deposition of hydroxyapatite.
Remarkable Long-term Stability of Cerasome as an Organic–Inorganic Hybrid Nanocontainer for Water-soluble Macromolecules
Authors: Kawataki Takahiro , Yasuhara Kazuma , Kikuchi Jun-ichi
Published: April 2011

The encapsulation characteristics of cerasome, an organic–inorganic hybrid vesicle, were clarified using a macromolecular fluorescent marker. The cerasome successfully entrapped the marker molecule in its inner aqueous space over a prolonged period in stark contrast to unstable phospholipid liposomes. In addition, the cerasome maintained its encapsulation ability in the presence of serum containing membrane-destabilizing lipoproteins.
Estimation of radiation exposure of retrospective gated and prospective triggered 128-slice triple-rule-out CT angiography
Authors: Ketelsen Dominik , Fenchel Michael , Thomas Christoph , Buchgeister Markus , Boehringer Nadine , Tsiflikas Ilias , Kaempf Michael , Claussen Claus D , Heuschmid Martin
Published: April 2011

Background

CT has become an important role in the differential diagnosis of acute chest pain to exclude an aortic dissection, pulmonary embolism and acute coronary artery syndrome. However, the additional radiation exposure is a cause of concern and dose saving strategies should be applied, if possible.

Purpose

To estimate effective dose of retrospective gated and prospective ECG-triggered triple-rule-out computed tomography angiography (TRO-CTA).

Material and Methods

An Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used for dose measurements. Exposure was performed on a 128-slice single source scanner. The following scan parameters were used (retrospective ECG-gated): 120 kV, 190 mAs/rot., collimation 128x0.6 mm, rotation time 0.3 s. Protocols with a simulated heart rate (HR) of 60 and 100 bpm were performed using the standard ECG-pulsing as well as MinDose. Additionally, a prospective triggered TRO-CTA was acquired (HR 60 bpm).

Results

The estimated effective dose of retrospective ECG-gated TRO-CTA ranged from 7.4–13.4 mSv and from 10.1–17.5 mSv for men and women, respectively. Due to radiosensitive breast tissue, women received a significant increased effective dose of up to 64.7% ± 0.03% (p = 0.028) compared to men. MinDose reduces radiation exposure of up to 33.0% ± 6.5% in comparison to standard ECG-pulsing (p < 0.001). The effective dose increased significantly with lower heart rates (p < 0.001). Prospective ECG-triggered TRO-CTA showed an effective dose of 5.9 mSv and 8.2 mSv for men and women, respectively. Compared to retrospective ECG-gated TRO-CTA a significant dose reduction was observed (p < 0.001).

Conclusion

Due to the significant different dose exposure, scan protocols should be specifically adapted in a patient- and problem-oriented manner.
Detection of pulmonary embolism using 64-slice multidetector-row computed tomography: accuracy and reproducibility on different image reconstruction parameters
Authors: Jung Jung Im , Kim Ki Jun , Ahn Myeong Im , Kim Hyo Rim , Park Hyun Jin , Jung SeungHee , Lim Hyeon Woo , Park Seog Hee
Published: April 2011

Background

Direct comparison of different image reconstruction parameters to detect pulmonary embolism (PE) using 64-slice multidetector-row computed tomography (MDCT) is absent and the most accurate image reconstruction parameters have not yet been proven.

Purpose

To compare different image reconstruction parameters for detecting PE using 64-slice MDCT in patients suspected of having an acute PE.

Material and Methods

Forty patients who underwent pulmonary CT angiography with 64-slice MDCT for a suspected PE were included. Different image reconstruction parameters were used for each patient: axial and coronal images with slice thicknesses of 0.625 mm, 1.3 mm, and 2.5 mm and axial maximum intensity projection (MIP) images with slab thicknesses of 1.3 mm, 2.5 mm, and 5 mm. Four experienced radiologists reviewed the images. The diagnosis of a PE was based on consensus review of axial 0.625 mm slice thickness images by two chest radiologists with allowing multiplanar reconstruction. Accuracy and reproducibility (kappa value) were evaluated.

Results

In 15 of 40 patients, a PE was diagnosed. For detecting lobar PEs, axial images with a slice thickness of 1.25 mm and all coronal re-formatted images showed comparable results to axial images with a slice thickness of 0.625 mm. For detecting segmental PEs, axial images with a slice thickness of 1.25 mm and coronal images with a slice thickness of 0.625 mm re-formatted images showed comparable results to axial images of a slice thickness of 0.625 mm. For detecting subsegmental PEs, axial images with a slice thickness of 0.625 mm showed the highest sensitivity. Better reproducibility was obtained when the thinner slice thickness reconstructions were in axial and coronal images. However, reproducibility of MIP images with slab thicknesses of 2.5 mm and 5 mm was similar for detecting segmental and subsegmental PEs.

Conclusion

Thin-slice reconstruction of less than 1 mm is mandatory for visualization of PE at the subsegmental level.
Physicians’ knowledge about ionizing radiation and radiological imaging techniques: a cross-sectional survey
Authors: Yucel Aylin , Alyesil Cansu , Sim Saadet
Published: April 2011

Background

Radiological examinations are critical for the evaluation of many disorders in daily practice.

Purpose

To determine the knowledge of ionizing radiation and radiological imaging techniques among physicians of various grades.

Material and Methods

A cross-sectional survey was carried out of 55 physicians with a mean age of 35.7 ± 6.0 years (age range 25–52 years) in a university hospital. A questionnaire which tested physicians’ information about ionizing radiation and their risks was distributed by medical school students.

Results

Among the participants, 32 (58.2%) were consultants and 23 (41.8%) were residents. The mean score was 68.2 ± 11.1 (range 37.8–91.8) out of 100. Consultants’ points were lower than residents (p = 0.040). Consultants had significantly higher frequency of incorrect answer than residents in the question about ‘whether CT scan increases lifetime cancer risk’ (p = 0.036).

Conclusion

Medical practices in years do not enhance the level of the awareness regarding the ionizing radiation.
Double reading of radiological examinations in Norway
Authors: Husby Jenny A , Espeland Ansgar , Kalyanpur Arjun , Brocker Carsten , Haldorsen Ingfrid S
Published: April 2011

Background

Double reading of images is a part of the quality assurance activities at many radiological centers.

Purpose

To investigate the extent of and routines for double reading in Norway and the institutional heads' attitudes toward double reading.

Material and Methods

A questionnaire was addressed to the heads of all radiological institutions in Norway. The questionnaire concerned staffing, examinations performed, extent of double reading per imaging modality (except mammography screening), guidelines for double reading, checks of completed radiology reports, frequency of regular quality assurance meetings to discuss missed findings, and the heads' attitudes toward double reading.

Results

The response rate was 73% (53/73). The percentage across imaging modalities of examinations being double read was 41% overall: 56% at university hospitals, 37% at local hospitals, and 18% at private centers. Double reading was most common for positron emission tomography (PET)/PET-computed tomography (CT) examinations (100%), and clinical mammography (91%). Almost all examinations read by residents were double read. Only 15% of institutions had written guidelines for double reading, 15% performed random double readings of completed examinations, and 55% organized regular meetings to discuss missed findings. Forty-six percent of the institutional heads wanted an increased use of double reading.

Conclusion

Double reading is common in Norway, especially in residency training, mammography, and PET/PET-CT. It is less common at private centers. Established routines for double reading are scarce. Many institutional heads want more double reading. The potential of double reading to assure quality in radiology should be better exploited.
Rarity of isolated pulmonary embolism and acute aortic syndrome occurring outside of the field of view of dedicated coronary CT angiography
Authors: Lee Hwa Yeon , Song In Sup , Yoo Seung Min , Rho Ji Young , Moon Jae Youn , Kim In Jai , Lim Sang Wook , Sung Jung Hoon , Cha Dong Hun , White Charles S
Published: April 2011

Background

Although triple rule-out CT angiography (TRO) to simultaneously evaluate acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic syndrome (AAS) is increasingly used in many institutions, TRO is inevitably associated with increased radiation exposure due to extended z-axis coverage compared with dedicated coronary CT angiography (DCTA).

Purpose

To determine the frequency of exclusion of findings of AAS, PE, and significant incidental non-cardiac pathology that may be the cause of acute chest pain when using a restricted DCTA field of view (FOV).

Material and Methods

We retrospectively reviewed CT images and charts of 103 patients with acute PE and 50 patients with AAS. Either non-ECG gated dedicated pulmonary or aortic CT angiography was performed using 16- or 64-slice multidetector CT (MDCT). We analyzed the incidence of isolated PE, AAS, or significant non-cardiac pathology outside of DCTA FOV (i.e. from tracheal carina to the base of heart).

Results

There were two cases of isolated PE (2/103, 1.9%) excluded from the FOV of DCTA. One case of PE was isolated to the subsegmental pulmonary artery in the posterior segment of the right upper lobe. In the second case, pulmonary embolism in the left main pulmonary artery was located out of the FOV of DCTA because the left main pulmonary artery was retracted upwardly by fibrotic scar in the left upper lobe due to prior tuberculosis. There was no case of AAS and significant non-cardiac pathology excluded from the FOV of DCTA. AAS ( n = 50) consisted of penetrating atherosclerotic ulcer ( n = 7), intramural hematoma ( n = 5) and aortic dissection ( n = 38).

Conclusion

As isolated PE, AAS, and significant non-cardiac pathology outside of the DCTA FOV rarely occur, DCTA may replace TRO in the evaluation of patients with non-specific acute chest pain and a low pre-test probability of PE or aortic dissection.
Pediatric and adult primary sarcomas of the kidney: a cross-sectional imaging review
Authors: Lalwani Neeraj , Prasad Srinivasa R , Vikram Raghu , Katabathina Venkat , Shanbhogue Alampady , Restrepo Carlos
Published: April 2011

There is a wide pathological spectrum of kidney sarcomas that show characteristic histology, ontogeny, and clinical-biological behavior. While leiomyosarcomas commonly arise from the capsule, solitary fibrous tumors and clear cell sarcomas typically show renal sinus and medullary epicenter, respectively. Although distribution and imaging findings of some sarcomas may be characteristic, definitive diagnosis warrants histopathological examination following surgery. Renal sarcomas manifest advanced disease at presentation and portend poor prognosis.
Learning aspects and potential pitfalls regarding detection of pulmonary nodules in chest tomosynthesis and proposed related quality criteria
Authors: Asplund Sara , Johnsson Åse A , Vikgren Jenny , Svalkvist Angelica , Boijsen Marianne , Fisichella Valeria , Flinck Agneta , Wiksell Åsa , Ivarsson Jonas , Rystedt Hans , Månsson Lars Gunnar , Kheddache Susanne , Båth Magnus
Published: April 2011

Background

In chest tomosynthesis, low-dose projections collected over a limited angular range are used for reconstruction of an arbitrary number of section images of the chest, resulting in a moderately increased radiation dose compared to chest radiography.

Purpose

To investigate the effects of learning with feedback on the detection of pulmonary nodules for observers with varying experience of chest tomosynthesis, to identify pitfalls regarding detection of pulmonary nodules, and present suggestions for how to avoid them, and to adapt the European quality criteria for chest radiography and computed tomography (CT) to chest tomosynthesis.

Material and Methods

Six observers analyzed tomosynthesis cases for presence of nodules in a jackknife alternative free-response receiver-operating characteristics (JAFROC) study. CT was used as reference. The same tomosynthesis cases were analyzed before and after learning with feedback, which included a collective learning session. The difference in performance between the two readings was calculated using the JAFROC figure of merit as principal measure of detectability.

Results

Significant improvement in performance after learning with feedback was found only for observers inexperienced in tomosynthesis. At the collective learning session, localization of pleural and subpleural nodules or structures was identified as the main difficulty in analyzing tomosynthesis images.

Conclusion

The results indicate that inexperienced observers can reach a high level of performance regarding nodule detection in tomosynthesis after learning with feedback and that the main problem with chest tomosynthesis is related to the limited depth resolution.
Periportal edema in trauma patients: correlation with trauma severity
Authors: Kuhlemann Julia , Loegters Tim , Roehlen Singha , Miese Falk R , Blondin Dirk , Kröpil Patric , Schellhammer Frank , Scherer Axel , Lanzman Rotem S
Published: April 2011

Background

Periportal edema (PPE) can be seen in different clinical settings, including in patients following trauma. However, the underlying mechanisms and clinical significance in trauma patients still remain unclear.

Purpose

To determine the incidence of PPE in CT scans of trauma patients and to correlate PPE with trauma severity and different patterns of injury.

Material and Methods

We retrospectively analyzed contrast-enhanced spiral CT scans of 127 trauma patients that were referred to our Trauma Center Level I between January 2006 and June 2007. According to the Injury Severity Score (ISS), 70 patients with an ISS < 16 (minor trauma) were assigned to group 1 and 57 patients with an ISS ≥16 (major trauma) to group 2.

Results

The presence of PPE was significantly (p < 0.01) higher in group 2 (22 of 57 patients [38.6%]) than in group 1 (10 of 70 patients [14.3%]). In 29 patients PPE presented with a diffuse pattern and in three patients with a focal pattern, affecting only one liver lobe. In 14 patients PPE was found in absence of abdominal injuries. In addition, PPE was present in five patients with abdominal injuries but without liver injury.

Conclusion

PPE is seen significantly more often on abdominal CT scans following major traumas (ISS ≥ 16), but is not necessarily associated with liver injury.
Ventricular septal aneurysms in adults: findings of cardiac CT images and correlation with clinical features
Authors: Choi Maria , Jung Jung Im , Lee Bae Young , Kim Hyo Rim
Published: April 2011

Background

With the increasing use of multidetector computed tomography (MDCT), the number of incidentally detected ventricular septal aneurysms (VSAs) in adults has increased. However, to date, there are not sufficient well-organized data regarding VSAs in adults on MDCT.

Purpose

To evaluate the CT findings of ventricular septal aneurysms (VSAs) in adults and correlate the findings with clinical features.

Material and Methods

We performed a retrospective review of the cardiac CT reports in our electronic database of 3402 patients who underwent ECG-gated cardiac CT scans using a 64-slice multidetector CT or dual-source CT from October 2006 to December 2009 at our institute. Among them, eight patients were diagnosed with a VSA. We evaluated the location, size, and morphology of VSAs on cardiac CT angiographies (CCTAs) and correlated the findings with the clinical features of the patients.

Results

On CCTAs, all eight patients were found to have VSAs in the membranous portion of the interventricular septum and toward the right ventricle. The VSAs were 10–22 mm at their longest diameter and had wide necks. The VSAs were lobulated along the outer margin and were incidental findings in all patients. Four of the eight patients had a conduction abnormality such as first-degree atrio-ventricular block or incomplete right bundle branch block seen on ECG, whereas the other four patients had normal ECGs.

Conclusion

VSA in adults is usually detected incidentally. It is seen in the membranous portion of the interventricular septum with a lobulated shape on CCTA. It is occasionally associated with a conduction anomaly.
Ischemic liver injuries after hepatic artery embolization in patients with delayed postoperative hemorrhage following hepatobiliary pancreatic surgery
Authors: Cho Sung Ki , Kim Sam Soo , Do Young Soo , Park Kwang Bo , Shin Sung Wook , Park Hong Suk , Choo Sung Wook , Choo In Wook
Published: April 2011

Background

Many collateral pathways to the liver are dissected during hepatobiliary pancreatic surgery and, if the arterial bleeding is massive and a hematoma becomes larger, the adjacent portal vein can be compressed with impairment of the portal venous flow.

Purpose

To evaluate the frequency and severity of ischemic liver injuries after hepatic artery embolization in patients with delayed postoperative arterial hemorrhage after hepatobiliary pancreatic surgery.

Material and Methods

Eighteen patients undergoing proper or common hepatic artery embolization for delayed postoperative arterial hemorrhage after hepatobiliary pancreatic surgery achieved hemostasis. To evaluate the frequency and severity of ischemic liver injuries, the liver enzyme levels and CT findings before and after hepatic artery embolization were retrospectively compared and the clinical outcomes after hepatic artery embolization were analyzed. Angiographic findings were also analyzed to reveal any association with development of ischemic liver injuries after hepatic artery embolization.

Results

Ischemic liver injuries were observed in 15 (83%) of 18 patients undergoing hepatic artery embolization for postoperative hemorrhage. Injuries included hepatic infarction combined with abscess in one (5%) patient, hepatic infarction in 12 (67%) patients, and transient hepatic ischemia/dysfunction in two (11%). As for the extent of hepatic infarction, lobar infarction developed in two patients and subsegmental infarction in 11. One patient with right hepatic lobar infarction died of hepatic failure 11 days after hepatic artery embolization. In the other 14 patients with ischemic liver injuries, the elevated liver enzymes returned to baseline levels within two weeks. All of the four patients with portal vein stenosis, four patients with no hepatic arterial flow on post-embolization angiogram, and one patient with both had hepatic infarction after hepatic artery embolization. No ischemic liver injuries developed after hepatic artery embolization in three patients with no portal vein stenosis and bilobar hepatic arterial flow via the left hepatic artery aberrantly arising from the left gastric artery or from the common hepatic artery.

Conclusion

Ischemic liver injuries can develop in most patients undergoing hepatic artery embolization for postoperative arterial hemorrhage after hepatobiliary pancreatic surgery; hepatic infarction appears to be the most frequent type of ischemic liver injury. Hepatic artery embolization for postoperative arterial hemorrhage after hepatobiliary pancreatic surgery may carry a great risk of ischemic liver injury if a patient has portal vein stenosis or no aberrant hepatic artery.
Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging for prostate lesions and normal tissue at 3.0-Tesla magnetic resonance imaging
Authors: Liu Xiaohang , Zhou Liangping , Peng Weijun , Qian Min
Published: April 2011

Background

Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined.

Purpose

To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI).

Material and Methods

Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm2 before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test.

Results

No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm2/s Vs 0.89 ± 0.12 mm2/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm2/s vs. 1.2 ± 0.29 mm2/s, p < 0.0001). No significant differences were detected for normal tissue.

Conclusion

The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in interpretation.
Dynamic CT and MRA findings of a case of portopulmonary venous anastomosis (PPVA) in a patient with portal hypertension: a case report and review of the literature
Authors: Ko Jeong Min , Ahn Myeong Im , Han Dae Hee , Jung Jung Im , Park Seog Hee
Published: April 2011

Portopulmonary venous anastomosis (PPVA), which has been rarely reported in conventional CT and MR studies, is an unusual collateral pathway in patients with portal hypertension. It has clinical implications related to right-to-left shunt that are different from the clinical implications related to other more usual portosystemic shunts in portal hypertensive patients. Here, we report the dynamic CT and MRA findings of a case of PPVA in a patient with portal hypertension, directly demonstrating the shunt flow from the paraesophageal varix to the left atrium via the right inferior pulmonary vein.
Musculoskeletal tuberculosis – imaging using low-end and advanced modalities for developing and developed countries
Authors: Andronikou Savvas , Bindapersad Manitha , Govender Nishentha , Waner Jonathan I , Segwe Aobakwe , Palliam Samantha , Shenxane Odwa , Mngomezulu Victor
Published: April 2011

Musculoskeletal involvement by TB is rare in comparison to other forms of the disease. It most commonly involves the spine but can also involve large weight-bearing joints, long bones, the skull and the soft tissues. Characteristic appearances of musculoskeletal TB are described for numerous imaging modalities in this paper but it is also highlighted that when based on imaging appearances alone, there is always a differential diagnosis, including other infections and malignancies. Awareness of of TB as a possible cause of vertebral body lesions, arthritis and synovitis, long bone lesions and soft tissue collections will allow clinicians to consider TB based on imaging and will sometimes be characteristic enough to allow for a trial of therapy, thereby avoiding biopsy. This paper specifically describes the imaging appearances on both basic modalities such as plain radiographs and ultrasound for those working in resource-restricted areas, as well as on high-end modalities such as CT and MRI for those with access to these. Tuberculosis is no longer a disease limited to the developing world and radiologists in the developed world must be able to make this diagnosis in both immigrants and the native population.
Usefulness of semi-automatic volumetry compared to established linear measurements in predicting lymph node metastases in MSCT
Authors: Buerke Boris , Gerss Joachim , Puesken Michael , Weckesser Matthias , Heindel Walter , Wessling Johannes
Published: April 2011

Background

Volumetry of lymph nodes potentially better reflect asymmetric size alterations independently of lymph node orientation in comparison to metric parameters (e.g. long-axis diameter).

Purpose

To distinguish between benign and malignant lymph nodes by comparing 2D and semi-automatic 3D measurements in MSCT.

Material and Methods

FDG-18 PET-CT was performed in 33 patients prior to therapy for malignant melanoma at stage III/IV. One hundred and eighty-six cervico-axillary, abdominal and inguinal lymph nodes were evaluated independently by two radiologists, both manually and with the use of semi-automatic segmentation software. Long axis (LAD), short axis (SAD), maximal 3D diameter, volume and elongation were obtained. PET-CT, PET-CT follow-up and/or histology served as a combined reference standard. Statistics encompassed intra-class correlation coefficients and ROC curves.

Results

Compared to manual assessment, semi-automatic inter-observer variability was found to be lower, e.g. at 2.4% (95% CI 0.05–4.8) for LAD. The standard of reference revealed metastases in 90 (48%) of 186 lymph nodes. Semi-automatic prediction of lymph node metastases revealed highest areas under the ROC curves for volume (reader 1 0.77, 95%CI 0.64–0.90; reader 2 0.76, 95%CI 0.59–0.86) and SAD (reader 1 0.76, 95%CI 0.64–0.88; reader 2 0.75, 95%CI 0.62–0.89). The findings for LAD (reader 1 0.73, 95%CI 0.60–0.86; reader 2 0.71, 95%CI 0.71, 95%CI 0.57–0.85) and maximal 3D diameter (reader 1 0.70, 95%CI 0.53-0.86; reader 2 0.76, 95%CI 0.50–0.80) were found substantially lower and for elongation (reader 1 0.65, 95%CI 0.50–0.79; reader 2 0.66, 95%CI 0.52–0.81) significantly lower (p < 0.05).

Conclusion

Semi-automatic analysis of lymph nodes in malignant melanoma is supported by high segmentation quality and reproducibility. As compared to established SAD, semi-automatic lymph node volumetry does not have an additive role for categorizing lymph nodes as normal or metastatic in malignant melanoma.
Mixed endometrioid and serous carcinoma developing in abdominal wall endometriosis following Cesarean section
Authors: Da Ines David , Bourdel Nicolas , Charpy Cécile , Montoriol Pierre François , Petitcolin Virginie , Canis Michel , Garcier Jean-Marc
Published: April 2011

Abdominal wall endometriosis is unusual and mostly occurs in scars following Cesarean section. Although malignant transformation is rare, it must be recognized in order to benefit from radical resection. We report a very rare case of mixed endometrioid and serous carcinoma developing in a Cesarean section endometriosis scar and the way we managed it using surgery and chemotherapy. 18-FDG PET-CT imaging was performed to correctly stage the disease.
High incidence of nephropathy in neurosurgical patients after intra-arterial administration of low-osmolar and iso-osmolar contrast media
Authors: Serafin Zbigniew , Karolkiewicz Maciej , Gruszka Marzena , Stróżecki Paweł , Lasek Władysław , Odrowąż-Sypniewska Grażyna , Manitius Jacek , Beuth Wojciech
Published: April 2011

Background

Percutaneous endovascular examinations and interventions require significant amounts of iodinated contrast media (CM) and have been reported to be complicated by an increased incidence of post-contrast nephropathy.

Purpose

To evaluate renal function, the incidence of post-contrast nephropathy, and risk factors after interventional procedures in neurosurgical patients after intra-arterial administration of a low-osmolar contrast medium (LOCM) versus an iso-osmolar contrast medium (IOCM).

Material and Methods

This single-center, prospective, randomized, double-blinded study included 92 patients in its final analysis (mean age 49.6 ± 12.6 years, 29.3% men, mean eGFR 97.8 ± 26.3 mL/min/1.73 m2). LOCM was used in 48 patients (52.2%) and IOCM in 44 patients (47.8%). The patients were given an average of 151.2 ± 52.1 mL of contrast medium intra-arterially. Serum creatinine (SCr), urinary N-acetyl-β-glucosaminidase (NAG) excretion, and creatinine clearance (CCr) were measured at baseline, and on days 1 and 3 after the procedure.

Results

Baseline risk factors, renal functional parameters, and average CM doses were not statistically different between the two groups. SCr, NAG, and CCr values did not differ significantly between the LOCM and IOCM groups on days 1 and 3 after CM administration. Nephropathy developed in 21 cases (22.8%): 13 (27.1%) after LOCM use and 8 (18.2%) after IOCM; (P = NS). The only significant risk factors of CIN were the diabetes ( P = 0.0466) and atherosclerosis ( P = 0.0498).

Conclusion

We found a high incidence of nephropathy in neurosurgical patients after intra-arterial CM administration. The renal function values and incidence of nephropathy following LOCM administration were not statistically different from those following IOCM administration.
Chondromyxoid fibroma of the rib mimics a chondrosarcoma on 18F-FDG PET/CT
Authors: Makis William , Ciarallo Anthony , Lisbona Robert
Published: April 2011

Chondromyxoid fibroma (CMF) is a rare benign bone tumor of chondroid origin that occurs mostly in the metaphyses of long bones. CMF can occasionally mimic a chondrosarcoma on CT, and the literature on the 18F-FDG PET/CT imaging characteristics of CMF tumors is limited. In the presented case, a large histologically proven CMF chest wall mass was initially misinterpreted as a chondrosarcoma. This case highlights a potential pitfall in the PET/CT evaluation of these rare benign bone tumors.
Ultrasound in the diagnosis of ovarian dermoid cysts: a pictorial review of the characteristic sonographic signs
Authors: Williams P L , Dubbins P A , Defriend D E
Published: April 2011

Dermoid cysts (mature cystic teratoma) are the commonest germ cell neoplasm and in some series the most commonly excised ovarian tumour. They are composed of tissue from at least two of the germ cell layers and often contain hair, sebum and teeth. These tumours show a wide range of ultrasonic appearances because of their variable composition. On account of this they may mimic a variety of other pelvic masses. In many cases, however, the ultrasonic appearance can be distinctive, and a number of sonographic signs characteristic of dermoid cysts have been described. Typical appearances include a shadowing echodensity or dermoid plug; diffuse or regional high amplitude echoes; the tip of the iceberg sign; dermoid mesh; fat–fluid levels and intracystic floating balls. When two or more characteristic signs are present, a high positive predictive value and a confident sonographic diagnosis can be achieved.

We present a pictorial review of the characteristic sonographic signs helpful in making the diagnosis of ovarian dermoid cyst. We also discuss the pitfalls of making an ultrasound diagnosis, and illustrate some of the conditions that may mimic dermoid cysts. We include correlation with computed tomography and magnetic resonance imaging where appropriate.
From embolization to remodeling: the need for early carotid endarterectomy in symptomatic carotid plaques
Authors: Capoccia Laura , Pelonara Caterina , Imondi Cesira , Sbarigia Enrico , Speziale Francesco
Published: April 2011

Atheromatous plaques are dynamic structures undergoing continuous remodeling. Duplex ultrasound is now an accepted technique to classify the severity of arterial stenoses. It gives information about the ultrasonic echogenicity of tissue, the plaque surface and the velocity of blood flowing through vessels with the latest equipment. We report the case of a 59-year-old male patient with left hemispheric stroke and a 50% left carotid artery stenosis whose remodeling and reabsorption developed throughout three months from the onset of symptoms. Plaque surface and structural echomorphology assessment and standardization, along with the degree of carotid stenosis, might be helpful in identifying patients most likely to benefit from carotid endarterectomy.
Asymptomatic lower extremity acrocyanosis: report of two cases and review of the literature
Authors: Glazer Evan , Pacanowski John P , Leon Luis R
Published: April 2011

Vasospastic disorders affecting the lower extremities are unusual entities. Two cases of asymptomatic foot discoloration with lower extremity dependency are presented. In the first case, an elderly gentleman was admitted to the hospital with a contralateral foot infection. His physical exam revealed pulse examination within normal limits and his blood work failed to identify any known causes for vasospasm. His foot infection was successfully treated with sensitivity-directed antibiotics. The second case is that of a young man with a history of quadriplegia secondary to a remote diving accident, who presented with a three-month history of foot discoloration while sitting up in his wheelchair, which resolved with recumbent leg positioning. A review of the possible diagnoses for these patients' presentation is presented herein.
Ethylene vinyl alcohol copolymer (Onyx) to seal type 1 endoleak. A new technique
Authors: Henrikson Olof , Roos Håkan , Falkenberg Mårten
Published: April 2011

The aim of this study was to investigate whether the liquid embolic agent Onyx, an ethylene vinyl alcohol copolymer, can be used to seal type 1 endoleaks during endovascular aortic repair (EVAR). Six patients with large aortic aneurysms and remaining type 1 endoleaks during or after EVAR were treated with Onyx embolization through a microcatheter placed in the proximal neck in five cases and in the distal neck in one case. Four of the patients were treated using the chimney technique. The type 1 endoleak was primarily sealed by Onyx in all six patients. There was no distal embolization. Two patients had complications during follow-up. One patient had occlusions of chimney grafts to the renal arteries and to one leg extension. These occlusions were not anatomically related to Onyx embolization. One patient had late stentgraft migration of the Onyx-treated distal neck with aneurysm rupture 18 months after treatment. Early experience of Onyx embolization as a bailout solution of type 1 endoleaks after complicated EVAR is promising. However, effective seal with Onyx does not prevent late stentgraft migration. More reported patients and longer follow-up are necessary to evaluate this new technique.
Histological analysis of cobalt–chromium stents with and without Camouflage® polymer coating: experimental porcine carotid artery model
Authors: Grudtner Marco Aurélio , de Lara Elesbão Joao Luiz , Gutierrez Paulo Sérgio , Meyer Fabíola Schons , Pereira Adamastor Humberto
Published: April 2011

This study evaluated the arterial response to cobalt–chromium stents with and without polymer coating (Camouflage®, Hemoteq AG, Wuerselen, Germany) implanted in pigs. Cobalt–chromium balloon-expandable stents (4 × 16 mm) were implanted in the common carotid arteries of nine pigs. Histological analysis of endothelialization, inflammation and injury was performed one month later. All stents were successfully deployed, and all but one animal survived the 30 study days. All arteries were patent. Endothelialization was nearly complete in most sections of all carotid stents in both groups. There were mild inflammatory infiltrate and mild-to-moderate injury, which were associated with the stent shafts and not significantly different between groups. Our findings suggest that, in porcine carotid arteries, the histological response to balloon-expandable cobalt–chromium stents coated with polymer (Camouflage®, Hemoteq AG) is similar to the response to non-coated cobalt–chromium stents.
Utilization of Apple Pruning Residues as a Source of Biomass Energy: A Case Study in Isparta Province
Authors: Ekinci Kamil
Published: April 2011

The prefeasibility study of a biomass fuelled CHP based on a steam Rankine cycle employing back-pressure process proposed to utilize apple pruning residues as biomass sources to obtain bioenergy in Isparta Province was carried out. Since Eğirdir has the highest apple production among the districts of Isparta province, it is reasonable to build biomass fuelled CHP plant in Eğirdir district. Therefore, economical analysis was conducted for the catchment area with the radius of 59 km taking Eğirdir district as the central point. Both equations and data used to calculate the capital and operating cost of biomass CHP plants were obtained from the available literature. The production of electrical and heat energy, and revenues were evaluated. The economic viability of 7.8 MWe CHP plant was evaluated based on the net present value (NPV), benefit-to-cost ratio (B/C ratio), internal rate of return (IRR), and payback period (PBP) considering electricity purchase prices of 0.066 euro cent/kWh and heat sale price of 0.0225 euro cent/kWh. It has been concluded that certain financial mechanisms have to be put into effect, such as increasing market price of electricity produced from CHP plants to give an incentive to producers, as well as fundraising to support construction of CHP plants, and offering both long-term credits and tax breaks for investors.