Influence of Gadoxetate Disodium on Oxygen Saturation and Heart Rate during Dynamic Contrast-enhanced MR Imaging

PURPOSE

To investigate whether gadoxetate disodium affects peripheral capillary oxygen saturation (SpO2) and/or heart rate (HR) during dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging in patients with liver diseases.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, who waived the requirement for informed consent. Four hundred fifty-eight patients (171 women [mean age, 66.5 years; range, 23-87 years] and 287 men [mean age, 61.1 years; range, 25-89 years]) who underwent liver DCE MR imaging with gadoxetate disodium (0.025 mmol per kilogram of body weight) from October 28, 2013, to June 24, 2014, were included in this study. They were monitored for SpO2 and HR during DCE MR imaging. Motion artifact severity was graded by using a five-point scale, and transient severe motion (TSM) was defined by a score of at least 4. The association between TSM and baseline predictors was assessed, and HR and SpO2 at each postcontrast phase were compared with those at the precontrast phase in the TSM and non-TSM groups.

RESULTS

Four hundred thirty-six patients were included in the non-TSM group, and 22 were included in the TSM group. Although the motion score was the worst at the arterial phase, the observed mean differences in SpO2 and HR between the precontrast phase and the arterial phase were less than 1% and 5 beats per minute, respectively (mean SpO2 ± standard deviation for the non-TSM group, 96.7% ± 1.8 vs 96.9% ± 1.8 [P = .11]; SpO2 for the TSM group, 96.4% ± 1.6 vs 96.1% ± 1.6 [P > .99]) (HR for the non-TSM group, 68.9 beats per minute ± 12.4 vs 70.9 beats per minute ± 12.1 [P < .0001]; HR for the TSM group, 75.0 beats per minute ± 11.8 vs 79.9 beats per minute ± 10.2 [P < .0001]).

CONCLUSION

Intravenous gadoxetate disodium (a weight-based dose) does not cause changes in SpO2 and HR that lead to image quality degradation.

Early skin toxicity predicts better outcomes, and early tumor shrinkage predicts better response after cetuximab treatment in advanced colorectal cancer

Cetuximab-containing treatments for metastatic colorectal cancer have been shown to have higher overall response rates and longer progression-free and overall survival than other systemic therapies. Cetuximab-related manifestations, including severe skin toxicity and early tumor shrinkage, have been shown to be predictors of response to cetuximab. We hypothesized that early skin toxicity is a predictor of response and better outcomes in patients with advanced colorectal carcinoma. We retrospectively evaluated 62 patients with colorectal adenocarcinoma who had unresectable tumors and were treated with cetuximab in our institution. Skin toxicity grade was evaluated on each treatment day. Tumor size was evaluated using computed tomography prior to treatment and 4-8 weeks after the start of treatment with cetuximab.Patients with early tumor shrinkage after starting treatment with cetuximab had a significantly higher overall response rate (P = 0.0001). Patients with early skin toxicity showed significantly longer overall survival (P = 0.0305), and patients with higher skin toxicity grades had longer progression-free survival (P = 0.0168).We have shown that early tumor shrinkage, early onset of skin toxicity, and high skin toxicity grade are predictors of treatment efficacy and/or outcome in patients with advanced colorectal carcinoma treated with cetuximab.

Fractionated stereotactic radiotherapy using CyberKnife for the treatment of large brain metastases: a dose escalation study

AIMS

To evaluate the toxicity and efficacy of fractionated stereotactic radiotherapy (FSRT) with doses of 18-30 Gy in three fractions and 21-35 Gy in five fractions against large brain metastases.

MATERIALS AND METHODS

Between 2005 and 2012, 61 large brain metastases (≥ 2.5 cm in maximum diameter) of a total of 102 in 54 patients were treated with FSRT as a first-line therapy. Neurological symptoms were observed in 47 of the 54 patients before FSRT. Three fractions were applied to tumours with a maximum diameter ≥ 2.5 cm and <4 cm, and five fractions were used for brain metastases ≥ 4 cm. After ensuring that the toxicities were acceptable (≤ grade 2), doses were escalated in steps. Doses to the large brain metastases were as follows: level I, 18-22 Gy/three fractions or 21-25 Gy/five fractions; level II, 22-27 Gy/three fractions or 25-31 Gy/five fractions; level III, 27-30 Gy/three fractions or 31-35 Gy/five fractions. Level III was the target dose level.

RESULTS

Overall survival rates were 52 and 31% at 6 and 12 months, respectively. Local tumour control rates of the 102 total brain metastases were 84 and 78% at 6 and 12 months, respectively. Local tumour control rates of the 61 large brain metastases were 77 and 69% at 6 and 12 months, respectively. Grade 3 or higher toxicities were not observed.

CONCLUSIONS

The highest dose levels of 27-30 Gy/three fractions and 31-35 Gy/five fractions seemed to be tolerable and effective in controlling large brain metastases. These doses can be used in future studies on FSRT for large brain metastases.

Diffusion analysis with triexponential function in hepatic steatosis

Our purpose was to assess the influence of liver steatosis on diffusion by triexponential analysis. Thirty-three patients underwent diffusion-weighted magnetic resonance imaging with multiple b values for perfusion-related diffusion, fast free diffusion, and slow restricted diffusion coefficients (D p, D f, D s) and fractions (F p, F f, F s). They also underwent dual-echo gradient-echo imaging for measurement of the hepatic fat fraction (HFF). Of these, 13 patients were included in the control group and 20 in the fatty liver group with HFF >5 %. The parameters of the two groups were compared by use of the Mann-Whitney U test. The relationships between diffusion coefficients and HFFs were assessed by use of the Pearson correlation. D p and D f were reduced significantly in the steatotic liver group compared with those in the control group (D p = 27.72 ± 6.61 × 10(-3) vs. 33.33 ± 6.47 × 10(-3) mm(2)/s, P = 0.0072; D f = 1.70 ± 0.53 × 10(-3) vs. 2.06 ± 0.40 × 10(-3) mm(2)/s, P = 0.0224). There were no significant differences in the other parameters between the two groups. Furthermore, D p and D f were correlated with HFF (P < 0.0001, r = -0.64 and P = 0.0008, r = -0.56, respectively). Decreased liver perfusion in steatosis caused the reduction in D p, and extracellular fat accumulation and intracellular fat droplets in steatosis led to the reduction in D f. Thus, the influence of hepatic steatosis should be taken into consideration when triexponential function analysis is used for assessment of diffuse liver disease.

Importance of the six angiosomes concept through arterial-arterial connections in CLI

AIM

We reviewed the importance of six angiosomes concept in the foot area through arterial-arterial connections.

METHODS

We retrospectively analyzed 145 limbs from 111 critical limb ischemia (CLI) patients to investigate whether the wound location corresponded with the occlusion of the feeding artery. We also analyzed 57 limbs that underwent endovascular therapy (EVT). Regardless of which target vessel underwent EVT in the calf area, it was considered "direct" if the feeding artery flow in the foot area was achieved and "indirect" if not achieved. The wound healing rate was compared between the direct group and the indirect group relative to the six angiosomes of the foot. Further, we analyzed the absolute difference of the skin perfusion pressure (SPP) values measured before and after EVT.

RESULTS

A concordance rate of 82.1% (119/145 limbs) was observed between the wound location and the site of vessel occlusion. The wound healing rate of the six angiosomes-direct group was significantly higher than that of the six angiosomes-indirect group (96.6% vs. 72.7%; P=0.03). The SPP values were significantly higher in the six angiosomes-direct group than those in the six angiosomes-indirect group (20.3±18.1 mmHg vs. 5±14.5 mmHg; P=0.039).

CONCLUSION

In the case of the patency of the arterial-arterial connections, even if one undergoes EVT for any of the three vessels in the lower leg, wound healing is likely to be achieved, if we can achieve six angiosome-direct flow.

Impact of excision repair cross-complementing gene 1 (ERCC1) on the outcomes of patients with advanced gastric cancer: correlative study in Japan Clinical Oncology Group Trial JCOG9912

BACKGROUND

Since the best chemotherapy regimen for each patient with advanced gastric cancer is uncertain, we aimed to identify molecular prognostic or predictive biomarkers from biopsy specimens in JCOG9912, a randomized phase III trial for advanced gastric cancer.

PATIENTS AND METHODS

Endoscopic biopsy specimens from primary lesions were collected in 445 of 704 randomized patients in JCOG9912. We measured the mRNA expression of excision repair cross-complementing group 1 (ERCC1), thymidylate synthase, dihydropyrimidine dehydrogenase, and five other genes, then, categorized them into low and high groups relative to the median, and examined whether gene expression was associated with efficacy end point.

RESULTS

Multivariate analyses showed that high ERCC1 expression [HR 1.37; 95% confidence interval (CI) 1.08-1.75; P = 0.010], performance status ≥ 1 (HR 1.45; 95% CI 1.13-1.86; P = 0.004), and number of metastatic sites ≥ 2 (HR 1.66; 95% CI 1.28-1.86; P < 0.001) were associated with a poor prognosis, and recurrent disease (versus unresectable; HR 0.75; 95% CI 0.56-1.00; P = 0.049) was associated with a favorable prognosis. None of these molecular factors were a predictive marker for choosing irinotecan plus cisplatin or 5-fluorouracil rather than S-1.

CONCLUSION

These correlative analyses suggest that ERCC1 is an independent prognostic factor for overall survival in the first-line treatment of gastric cancer.

CLINICAL TRIAL NUMBER

C000000062, www.umin.ac.jp.

The relationships between feeding-group size and feeding rate vary from positive to negative with characteristics of food items in wild Japanese macaques (Macaca fuscata)

To understand the costs and benefits of group-living, it is important to clarify the impacts of other individuals on foraging success. Previous studies on group-living primates have focused on the relationship between feeding-group size and feeding rate in food patches, and have exhibited inconsistent results, showing positive, neutral, or negative relationships. The relationship realized will depend on the balance of positive and negative impacts of co-feeding on feeding rate. The intensity of negative impacts (i.e., feeding competition) may vary with some characteristics of food items such as (1) patch size, (2) within-patch food density, (3) within-patch distribution pattern of food, (4) the abundance and (5) distribution pattern of within-habitat food trees, and (6) the relative energy content among available food items. Thus, the balance of positive and negative impacts of co-feeding, and ultimately the relationship between feeding-group size and feeding rate, is expected to change with characteristics of food items. In this study of wild Japanese macaques (Macaca fuscata), the relationship between feeding-group size and feeding rate, and the above six characteristics of 12 main food items were assessed over six seasons. Positive, neutral, or negative relationships between feeding-group size and feeding rate were detected among these food items. Positive relationships were consistently associated with within-patch food density; higher food density within food patches was likely to lead to positive relationships. Thus, various relationships between feeding-group size and feeding rate should be attributed to these specific characteristics of food items, which alter the degree of feeding competition.

Measurement of ion and electron temperatures in plasma blobs by using an improved ion sensitive probe system and statistical analysis methods

We have measured ion temperature as well as electron temperature in plasma blobs observed in a linear plasma device by using an improved ion sensitive probe. Current-voltage characteristics of the ion sensitive probe inside and outside plasma blobs were re-constructed with a conditional sampling method. It is clearly found that both ion and electron temperatures in plasma blobs decrease more slowly in a cross-field direction than those in a bulk plasma without plasma blobs.

An effective training system for endoscopic submucosal dissection of gastric neoplasm

BACKGROUND AND STUDY AIMS

A standard training system for endoscopic submucosal dissection (ESD) remains to be established. In this study, we evaluated the validity of our training program for gastric ESD.

PATIENTS AND METHODS

Four trainees performed gastric ESD for a total of 117 lesions in 107 patients (27 to 30 consecutive lesions per trainee) at a tertiary referral center during 2 years in the training program. Trainees, who already had the fundamental skills and knowledge needed for ESD, each assisted at 40 gastric ESD procedures, then in 20 cases applied post-ESD coagulation (PEC) to gastric mucosal defects; they then began to perform ESD, starting with gastric antral lesions. Treatment outcomes, including mean procedure time, and rates of en bloc resection, en bloc plus R0 resections, complications, and self-completion, were evaluated, for the initial 15 and subsequent 12 to 15 cases.

RESULTS

Overall rates of en bloc resection and en bloc plus R0 resection were as high as 100 % and 96.6 %, respectively. Regarding complications, seven cases of delayed hemorrhage (6.0 %) and three cases of perforation (2.6 %) occurred; all complications were solved endoscopically. The most frequent reason for operator change was lack of submucosal dissection skill. The self-completion rate was more than 80 % even in the early period, and did not increase for later cases.

CONCLUSIONS

Our training system enabled novice operators to perform gastric ESD without a decline in clinical outcomes. Key features of this training are prior intensive learning and actual ESD during the learning period under expert supervision.

Cyanobacterial lactate oxidases serve as essential partners in N2 fixation and evolved into photorespiratory glycolate oxidases in plants

Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N(2)-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to harbor genes for both GlcD and GOX proteins. The GOX-like proteins from Nostoc (No-LOX) and from Chlamydomonas reinhardtii showed high L-lactate oxidase (LOX) and low GOX activities, whereas glycolate was the preferred substrate of the phylogenetically related At-GOX2 from Arabidopsis thaliana. Changing the active site of No-LOX to that of At-GOX2 by site-specific mutagenesis reversed the LOX/GOX activity ratio of No-LOX. Despite its low GOX activity, No-LOX overexpression decreased the accumulation of toxic glycolate in a cyanobacterial photorespiratory mutant and restored its ability to grow in air. A LOX-deficient Nostoc mutant grew normally in nitrate-containing medium but died under N(2)-fixing conditions. Cultivation under low oxygen rescued this lethal phenotype, indicating that N(2) fixation was more sensitive to O(2) in the Δlox Nostoc mutant than in the wild type. We propose that LOX primarily serves as an O(2)-scavenging enzyme to protect nitrogenase in extant N(2)-fixing cyanobacteria, whereas in plants it has evolved into GOX, responsible for glycolate oxidation during photorespiration.

Purification and Properties of beta-N-Acetylhexosaminidase from Mucor fragilis Grown in Bovine Blood

Mucor fragilis grown on bovine blood powder as the sole carbon source abundantly produced beta-N-acetylhexosaminidase. The enzyme activity was several times higher than that of a culture obtained with glucose medium. The enzyme had two different molecular weight forms. The high-molecular-weight form had somewhat higher beta-N-acetylgalactosaminidase activity than the lower-molecular-weight enzyme which had beta-N-acetylgalactosaminidase activity equivalent to about 40% of its beta-N-acetylglucosaminidase activity. Bovine blood seemed to induce both enzymes, but N-acetylamino sugars specifically induced the low-molecular-weight form. N-Acetylgalactosamine had an especially marked effect on activity. The low-molecular-weight form of enzyme was purified from the culture filtrate by fractionation with ammonium sulfate and various column chromatographies. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The optimum pH was 4.0 to 5.0 for beta-N-acetylglucosaminidase activity and 5.5 to 6.5 for beta-N-acetylgalactosaminidase activity. The enzyme hydrolyzed natural substrates such as di-N-acetylchitobiose, tri-N-acetylchitotriose, and a glycopeptide obtained by modification of fetuin.

Effect of various estimates of renal function on prediction of vancomycin concentration by the population mean and Bayesian methods

OBJECTIVE

Renal function was estimated in 129 elderly patients with methicillin-resistant Staphylococcus aureus (MRSA) who were treated with vancomycin (VCM). The estimation was performed by substituting serum creatinine (SCR) measured enzymatically and a value converted using the Jaffe method into the Cockcroft-Gault and Modification of Diet in Renal Disease (MDRD) equations. The serum trough level was predicted from three estimates of renal function by the population mean (PM) and Bayesian methods and the predictability was assessed.

METHODS

Two-compartment model-based Japanese population parameters for VCM were used, and the mean prediction error (ME) and root mean squared error (RMSE) were calculated as indices of bias and accuracy, respectively, for predictions by the PM and Bayesian methods.

RESULTS

The PM method gave the highest correlation with the measured value using the estimate of renal function obtained by substituting the Jaffe-converted SCR into the Cockcroft-Gault equation. There was no positive or negative bias in the ME and the value was significantly smaller than for other predicted data (P < 0.05). RMSE was also the smallest, indicating that this method increases the predictability of the serum VCM trough level. While, ME showed a negative bias for all values predicted by the Bayesian method, both the ME and RMSE were very small.

CONCLUSION

In the application of the PM method for VCM treatment of elderly patients with MRSA, substitution of SCR based on the Jaffe method into the Cockcroft-Gault equation increases the predictability of the serum VCM trough level. The Bayesian method predicted the serum VCM trough level with high accuracy using any of the estimates of renal function.

Patterns of Renal Function in Hypertension Due to Unilateral Renal Artery Occlusion

We performed renal function studies in dogs with chronic renovascular hypertension produced by complete occlusion of a renal artery. In addition, we evaluated in anesthetized dogs the acute effects of a novel angiotensin converting enzyme inhibitor, CGS 16,617, on renal function and plasma neurohormones (epinephrine, norepinephrine and vasopressin) 4 weeks after initiation of 2 kidney, 1 clip hypertension. CGS 16,617 effectively decreased blood pressure in renal hypertensive animals. This response was associated with suppression of angiotensin II indicating effective converting enzyme inhibition. In the non-clipped kidney, acute administration of CGS 16,617 increased effective renal plasma flow but not glomerular filtration rate and urinary sodium excretion. In the clipped kidney, CGS 16,617 caused no change in any parameter of renal function. Plasma norepinephrine, epinephrine and vasopressin were unaffected by administration of CGS 16,617. These studies showed that chronic occlusion of a renal artery does not result in renal infarction because of a compensatory increase in the amount of blood provided through capsular collateral vessels. The collateral circulation which has developed in the clipped kidney explains the lack of a converting enzyme inhibitor effect.

Photosynthetic carbon assimilation in the coccolithophorid Emiliania huxleyi (Haptophyta): Evidence for the predominant operation of the c3 cycle and the contribution of {beta}-carboxylases to the active anaplerotic reaction

The coccolithophorid Emiliania huxleyi (Haptophyta) is a representative and unique marine phytoplankton species that fixes inorganic carbon by photosynthesis and calci-fication. We examined the initial process of photosynthetic carbon assimilation by analyses of metabolites, enzymes and genes. When the cells were incubated with a radioactive substrate (2.3 mM NaH(14)CO(3)) for 10 s under illumination, 70% of the (14)C was incorporated into the 80% methanol-soluble fraction. Eighty-five and 15% of (14)C in the soluble fraction was incorporated into phosphate esters (P-esters), including the C(3) cycle intermediates and a C(4) compound, aspartate, respectively. A pulse-chase experiment showed that (14)C in P-esters was mainly transferred into lipids, while [(14)C]aspartate, [(14)C]alanine and [(14)C]glutamate levels remained almost constant. These results indicate that the C(3) cycle functions as the initial pathway of carbon assimilation and that beta-carboxylation contributes to the production of amino acids in subsequent metabolism. Transcriptional analysis of beta-carboxylases such as pyruvate carboxylase (PYC), phosphoenolpyruvate carboxylase (PEPC) and phosphoenolpyruvate carboxykinase (PEPCK) revealed that PYC and PEPC transcripts were greatly increased under illumination, whereas the PEPCK transcript decreased remarkably. PEPC activity was higher in light-grown cells than in dark-adapted cells. PYC activity was detected in isolated chloroplasts of light-grown cells. According to analysis of their deduced N-terminal sequence, PYC and PEPC are predicted to be located in the chloroplasts and mitochondria, respectively. These results suggest that E. huxleyi possesses unique carbon assimila-tion mechanisms in which beta-carboxylation by both PYC and PEPC plays important roles in different organelles.

Unsatisfying functions and multiobjective fuzzy satisfaction design using genetic algorithms

This paper describes a new fuzzy satisfaction method using genetic algorithms (GA) for multiobjective problems. First, an unsatisfying function, which has a one-to-one correspondence with the membership function, is introduced for expressing "fuzziness". Next, the multiobjective design problem is transformed into a satisfaction problem of constraints by introducing an aspiration level for each objective. Here, in order to handle the fuzziness involved in aspiration levels and constraints, the unsatisfying function is used, and the problem is formulated as a multiobjective minimization problem of unsatisfaction ratings. Then, a GA is employed to solve the problem, and a new strategy is proposed to obtain a group of Pareto-optimal solutions in which the decision maker (DM) is interested. The DM can then seek a satisfaction solution by modifying parameters interactively according to preferences.

Combined treatment using CEA and CAS for carotid arterial stenosis

In this study we report our surgical results of CAS and CEA for carotid stenosis and suggest an appropriate treatment strategy for patients with high risks such as bilateral carotid stenosis or medical risk factors. From January 2001 to December 2005 we surgically treated 182 patients with carotid stenosis. Seventy-nine lesions were treated by CEA and 145 by CAS, respectively. Although CEA was considered the first choice for severe carotid stenosis, CAS was chosen for treatment when CEA was considered a higher risk for patients. Stenosis of carotid arteries was relieved in all cases after CEA or CAS. Surgical mortality of CEA was 1.1% (1/94). Surgical mortality of CAS was 0.7% (1/145). Carotid stenotic lesions can be treated with comparably low morbidity and mortality rates using CEA or/and CAS considering each characteristic of carotid stenosis of patients even with medically high risk or bilateral carotid stenosis.

Functional results of intersphincteric resection for low rectal cancer

BACKGROUND

Intersphincteric resection (ISR) is the ultimate sphincter-preserving operation for very low rectal cancer. The aim of this study was to assess defaecatory function after ISR in relation to the degree of resection of the internal anal sphincter.

METHODS

Between 2001 and 2003, 35 consecutive patients with low rectal cancer had curative ISR, categorized as total, subtotal or partial resection of the internal anal sphincter. Defaecatory function was assessed in terms of frequency of bowel movements and continence. Sphincter function was evaluated by manometric study and anorectal sensation testing before surgery and 3, 6 and 12 months afterwards.

RESULTS

Defaecatory function was satisfactory after ISR; 34 of 35 patients were grossly continent. The maximum resting anal canal pressure fell after all three procedures. Patients who had total ISR had reduced anal canal sensation at 3 months, but this had improved by 12 months after surgery.

CONCLUSION

These functional results suggest that ISR should be considered as an alternative to abdominoperineal resection for low rectal cancer. However, as the outcome for continence is worse after total ISR than subtotal or partial ISR, the indication for total ISR should strictly take into account the preoperative sphincter function.

Activation of mammalian target of rapamycin in postmenopausal ovarian endometriosis

The purpose of this study was to determine whether Akt and mammalian target of rapamycin (mTOR), downstream targets of phosphatidylinositol 3-kinase, are activated in endometriosis and ovarian cancer specimens. We measured total and phosphorylated levels of Akt and mTOR from 17 frozen ovarian cancers and 15 benign endometriosis specimens (nine from premenopausal women and six from postmenopausal women) by quantitation of signals from western blots using antibodies against these proteins. Elevated phospho-Akt was detected in ovarian cancer versus endometriosis specimens from premenopausal women and endometriosis specimens from postmenopausal women (2.3 +/- 0.45 versus 0.10 +/- 0.06 and 0.17 +/- 0.11; P < 0.05) when the western blot signal of activated kinase was normalized to total kinase levels. Elevated phospho-mTOR was detected in ovarian cancer and postmenopausal endometriosis versus premenopausal endometriosis (0.52 +/- 0.19 and 0.46 +/- 0.29 versus 0.13 +/- 0.08; P < 0.05). Expression of total kinases (normalized to beta-actin) was higher in carcinoma versus endometriosis specimens. Elevation of the active mTOR was specifically detected in postmenopausal endometriosis.

Clinical characteristics of acute encephalopathy of obscure origin: a biphasic clinical course is a common feature

OBJECTIVE

To evaluate the clinical characteristics of acute encephalopathy of obscure origin (AE).

STUDY DESIGN

We examined clinical, imaging, and laboratory findings in children with AE. Specific subtypes of AE such as Reye's syndrome (RS), acute necrotizing encephalopathy (ANE), hemorrhagic shock and encephalopathy (HSE), acute encephalitis with refractory, repetitive partial seizures (AERRPS), and hemiconvulsion-hemiplegia syndrome (HH) were diagnosed. Other AE patients were regarded as non-specific subtype.

RESULTS

Nineteen patients were identified; specific AEs in 14 and non-specific AE in 5. Patients with RS, ANE, HSE frequently showed neuroimaging abnormalities (9/9) and significant elevation of liver enzymes (7/9) within 2 days after onset. Prognoses were extremely poor; early death in 6 and severe neurological sequelae in 3. Two of the 3 HH patients and 4 of the 5 non-specific AE patients showed biphasic clinical courses (AEBC); consciousness levels transiently improved following initial seizures and were exacerbated at the fourth to sixth days. In AEBC, neuroimaging abnormalities were rarely observed during the acute phase (1/5) but were detectable at clinical exacerbation. They rarely showed severely abnormal elevation in liver enzymes (1/6) and resulted in mild to moderate neurological sequelae (6/6).

CONCLUSION

A biphasic clinical course is a common feature in HH and non-specific AE.

Scatter radiation in cephalometric radiography: the effects of grid and collimation

OBJECTIVES

To measure the scatter fraction in cephalometric radiography with and without a grid and to estimate the patient's dose reduction by using a specially fabricated collimator without a grid.

METHODS

A 16 cm thick water-equivalent phantom was used to measure the scatter fraction. The projection geometry was the same as our conventional one, i.e. the distance from the X-ray source to the centre of the phantom was 200 cm. A photostimulable phosphor plate was used as an X-ray sensor and was 20 cm from the centre of the phantom. The measurements were performed in four combinations: with an antiscatter grid in place, with a specially fabricated collimator in place, with neither in place, and with both in place. The images of a human dried skull were obtained by using the above parameters and were subjectively assessed for a visibility of several reference points.

RESULT

The scatter fraction in the regularly collimated geometry with the antiscatter grid in place was 0.35 for a relative exposure of 1. With the antiscatter grid removed, the scatter fraction increased to 0.68, but the relative exposure was reduced to 0.3. With a special collimator, the scatter fraction was reduced to some extent in all instances, but the exposure was reduced to 0.45. The visibility of the reference points was acceptable in all conditions.

CONCLUSION

In cephalometric radiography, removal of the antiscatter grid yields a significant reduction in exposure with no significant loss of information.