Forward-projected Model-based Iterative Reconstruction SoluTion in Temporal Bone Computed Tomography: A Comparison Study of All Reconstruction Modes.

OBJECTIVE: Identify appropriate reconstruction modes of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) in temporal bone computed tomography (CT) and investigate the contribution of spatial resolution and noise to the visual assessment. METHODS: Sixteen temporal bone CT images were reconstructed. Two blinded radiologists assessed 8 anatomical structures and classified the visual assessment. These visual scores were compared across reconstruction modes among each anatomical structure. Visual scores and contrast-to-noise ratio, noise power spectrum (NPS) at low (NPSLow) and high (NPSHigh) spatial frequencies, and 50% modulation transfer function relationships were evaluated. RESULTS: Visual scores differed significantly for the stapedius muscle and osseous spiral lamina, with CARDIAC SHARP, BONE, and LUNG modes for the osseous spiral lamina scoring highest. Visual scores significantly positively correlated with NPSLow, NPSHigh, and 50% modulation transfer function but negatively with contrast-to-noise ratio. CONCLUSIONS: Modes providing higher spatial resolution and lower noise reduction showed an improved visual assessment of CT images reconstructed with FIRST.

Computed tomography findings of early-stage TAFRO syndrome and associated adrenal abnormalities.

OBJECTIVES: To compare CT findings of early (within 3 weeks post-onset)- and later (within 1 month before or after diagnostic criteria were satisfied, and later than 3 weeks post-onset) stage thrombocytopenia, anasarca, fever, reticulin fibrosis, renal dysfunction, and organomegaly (TAFRO) syndrome. METHODS: Between 2014 and 2019, 13 patients with TAFRO syndrome (8 men and 5 women; mean age, 54.9 years) from nine hospitals were enrolled. The number of the following CT findings (CT factors) was recorded: the presence of anasarca, organomegaly, adrenal ischaemia, anterior mediastinal lesion, bony lesion, and lymphadenopathy. Records of adrenal disorders (adrenomegaly, ischaemia, and haemorrhage) throughout the disease course were also collected. Differences in CT factors at each stage were statistically compared between remission and deceased groups. RESULTS: Para-aortic oedema and mild lymphadenopathy were observed in all patients, whereas pleural effusion, ascites, and subcutaneous oedema were found in 5/13, 7/13, and 7/13 cases, respectively, at the early stage. CT factors at the early stage were significantly higher in the deceased than in the remission group (mean, 11 vs 6.5; p = 0.04), while they were nonsignificant at the later stage. Adrenal disorders were present in 7/13 cases throughout the course including 6 of adrenomegaly and 4 of ischaemia at the early stage. CONCLUSIONS: Para-aortic oedema and mild lymphadenopathy are most common at the early stage. Anasarca, organomegaly, lymphadenopathy, and adrenal disorders on early-stage CT are useful for unfavourable prognosis prediction. Moreover, adrenal disorders are frequent even at the early stage and are useful for early diagnosis of TAFRO syndrome. KEY POINTS: • CT findings facilitate early diagnosis and prognosis prediction in TAFRO syndrome. • Adrenal disorders are frequently observed in TAFRO syndrome. • Adrenal disorders are useful for differential diagnosis of TAFRO syndrome.

Comparison of image quality between synthetic and patients' electrocardiogram-gated 320-row pediatric cardiac computed tomography.

BACKGROUND: Pediatric cardiac computed tomography (CT) can be acquired without electrode placement by using synthetic electrocardiogram (ECG). OBJECTIVE: To determine whether the depiction of gross cardiac structures and coronary arteries in 320-row pediatric CT is not inferior when CT is gated with synthetic ECG at 150 beats per minute (bpm), compared to the patients' own ECG. MATERIALS AND METHODS: Sixty 320-row CT examinations performed in children younger than 3 years old with congenital cardiac anomaly were enrolled in this retrospective study. Thirty examinations were scanned using the children's own ECG for gating and 30 examinations were scanned using synthetic ECG at 150 bpm. The image quality was compared between the two gating modes using a 3-point scale to delineate the following anatomical structures: atrial septum, ventricular septum, right atrium, right ventricle, left atrium, left ventricle, main pulmonary artery, ascending aorta, aortic arch including the patent ductus arteriosus, descending aorta, right coronary artery and left main trunk. Beam-hardening artifacts from contrast enhancement material were evaluated using a 3-point scale, and the overall image quality was evaluated using a 5-point scale. RESULTS: Synthetic ECG was not inferior to the patients' ECG in depicting each structure, beam-hardening artifact and overall image quality. Average indices were clinically acceptable imaging quality, except for subjective image quality of mid and distal coronary arteries. CONCLUSION: Pediatric cardiac CT in patients younger than 3 years old can be acquired using synthetic ECG gating, with image quality not inferior to the patients' ECG.

Deep neural network-based computer-assisted detection of cerebral aneurysms in MR angiography.

BACKGROUND: The usefulness of computer-assisted detection (CAD) for detecting cerebral aneurysms has been reported; therefore, the improved performance of CAD will help to detect cerebral aneurysms. PURPOSE: To develop a CAD system for intracranial aneurysms on unenhanced magnetic resonance angiography (MRA) images based on a deep convolutional neural network (CNN) and a maximum intensity projection (MIP) algorithm, and to demonstrate the usefulness of the system by training and evaluating it using a large dataset. STUDY TYPE: Retrospective study. SUBJECTS: There were 450 cases with intracranial aneurysms. The diagnoses of brain aneurysms were made on the basis of MRA, which was performed as part of a brain screening program. FIELD STRENGTH/SEQUENCE: Noncontrast-enhanced 3D time-of-flight (TOF) MRA on 3T MR scanners. ASSESSMENT: In our CAD, we used a CNN classifier that predicts whether each voxel is inside or outside aneurysms by inputting MIP images generated from a volume of interest (VOI) around the voxel. The CNN was trained in advance using manually inputted labels. We evaluated our method using 450 cases with intracranial aneurysms, 300 of which were used for training, 50 for parameter tuning, and 100 for the final evaluation. STATISTICAL TESTS: Free-response receiver operating characteristic (FROC) analysis. RESULTS: Our CAD system detected 94.2% (98/104) of aneurysms with 2.9 false positives per case (FPs/case). At a sensitivity of 70%, the number of FPs/case was 0.26. DATA CONCLUSION: We showed that the combination of a CNN and an MIP algorithm is useful for the detection of intracranial aneurysms. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:948-953.

Full and hybrid iterative reconstruction to reduce artifacts in abdominal CT for patients scanned without arm elevation.

Background Abdominal computed tomography (CT) without arm elevation is associated with degraded image quality due to streak artifacts. Purpose To compare the degree of streak artifacts in abdominal CT images without arm elevation between full iterative reconstruction (IR), hybrid IR, and filtered back projection (FBP) using two commercially available scanners. Material and Methods First, a phantom study simulating CT examination without arm elevation was performed. Second, unenhanced axial images of 33 patients (17 and 16 patients for each vendor) who underwent CT without arm elevation were reconstructed with full IR, hybrid IR and FBP. A radiologist placed 50 parallel lines with lengths of 50 pixels vertical to the streaks and quantitatively evaluated the images for streak artifacts in the phantom study. Two radiologists evaluated the images of patients for streak artifacts (on the liver and the kidney) and diagnostic acceptability using a four-point scale. Results The phantom study indicated that full IR algorithms were more effective than FBP in reducing streak artifacts. In the clinical patient study, streak artifacts were significantly more reduced with full IR compared with FBP in both the liver and kidney ( P < 0.012). Streak artifact reduction was limited with hybrid IR. Model-based iterative reconstruction (MBIR) (one of the full IR algorithms) provided diagnostically more acceptable image quality ( P < 0.016) compared with FBP. Conclusion In abdominal CT without arm elevation, full IR enabled a more efficient streak artifact reduction compared with FBP and MBIR was associated with diagnostically more acceptable images.

Pediatric 320-row cardiac computed tomography using electrocardiogram-gated model-based full iterative reconstruction.

BACKGROUND: Full iterative reconstruction algorithm is available, but its diagnostic quality in pediatric cardiac CT is unknown. OBJECTIVE: To compare the imaging quality of two algorithms, full and hybrid iterative reconstruction, in pediatric cardiac CT. MATERIALS AND METHODS: We included 49 children with congenital cardiac anomalies who underwent cardiac CT. We compared quality of images reconstructed using the two algorithms (full and hybrid iterative reconstruction) based on a 3-point scale for the delineation of the following anatomical structures: atrial septum, ventricular septum, right atrium, right ventricle, left atrium, left ventricle, main pulmonary artery, ascending aorta, aortic arch including the patent ductus arteriosus, descending aorta, right coronary artery and left main trunk. We evaluated beam-hardening artifacts from contrast-enhancement material using a 3-point scale, and we evaluated the overall image quality using a 5-point scale. We also compared image noise, signal-to-noise ratio and contrast-to-noise ratio between the algorithms. RESULTS: The overall image quality was significantly higher with full iterative reconstruction than with hybrid iterative reconstruction (3.67±0.79 vs. 3.31±0.89, P=0.0072). The evaluation scores for most of the gross structures were higher with full iterative reconstruction than with hybrid iterative reconstruction. There was no significant difference between full and hybrid iterative reconstruction for the presence of beam-hardening artifacts. Image noise was significantly lower in full iterative reconstruction, while signal-to-noise ratio and contrast-to-noise ratio were significantly higher in full iterative reconstruction. CONCLUSION: The diagnostic quality was superior in images with cardiac CT reconstructed with electrocardiogram-gated full iterative reconstruction.

Usefulness of T2 star-weighted imaging in ovarian cysts and tumors.

AIM: The aim of this study was to investigate the prevalence of hypointensity on T2 star-weighted imaging (T2*WI), which is useful for detecting hemosiderin, in endometriomas and other ovarian tumors. The efficacy of detecting adhesions around ovarian tumors was also investigated. METHODS: Pelvic magnetic resonance (MR) examinations, including T2*WI, were carried out. The inclusion criteria were female patients with ovarian surgical treatments. One hundred seventeen patients with a total of 147 lesions were enrolled. Two radiologists retrospectively evaluated MR imaging (MRI) to predict ovarian pathology and the presence of adhesions. T2*WI hypointensity of the inside and outside along ovarian cysts/tumors was utilized to predict pathological diagnoses and the presence of adhesions, respectively. The kappa scores were calculated to measure interobserver agreement on MRI findings. The MRI interpretations were compared with the results of pathological investigation and surgical observations. RESULTS: Hypointensity inside along the cyst walls on T2*WI was observed in 100 out of 106 lesions of endometriomas (94.3%), and three out of 41 non-endometrial ovarian cysts/tumors (7.3%). Four different patterns of T2*WI were observed in ovarian cysts/tumors. The kappa score regarding T2*WI hypointensity inside along the cyst walls was 0.633. Using conventional routine pelvic MRI, the sensitivity for detecting adhesions around ovarian cysts was 84.5%. By adding T2*WI, the sensitivity improved to 91.4% (P < 0.01). With conventional methods to predict adhesions, the kappa score was 0.660. After adding T2*WI to the conventional methods, the kappa score was 0.767. CONCLUSION: Hypointensity on T2*WI was observed frequently in endometrioma. T2*WI also improved the sensitivity for detecting adhesions around ovarian cysts/tumors.

Diagnostic Phase of Calcium Scoring Scan Applied as the Center of Acquisition Window of Coronary Computed Tomography Angiography Improves Image Quality in Minimal Acquisition Window Scan (Target CTA Mode) Using the Second Generation 320-Row CT.

OBJECTIVE: To compare the image quality of coronary computed tomography angiography (CCTA) acquired under two conditions: 75% fixed as the acquisition window center (Group 75%) and the diagnostic phase for calcium scoring scan as the center (CS; Group CS). METHODS: 320-row cardiac CT with a minimal acquisition window (scanned using "Target CTA" mode) was performed on 81 patients. In Group 75% (n = 40), CS was obtained and reconstructed at 75% and the center of the CCTA acquisition window was set at 75%. In Group CS (n = 41), CS was obtained at 75% and the diagnostic phase showing minimal artifacts was applied as the center of the CCTA acquisition window. Image quality was evaluated using a four-point scale (4-excellent) and the mean scores were compared between groups. RESULTS: The CCTA scan diagnostic phase occurred significantly earlier in CS (75.7 ± 3.2% vs. 73.6 ± 4.5% for Groups 75% and CS, resp., p = 0.013). The mean Group CS image quality score (3.58 ± 0.63) was also higher than that for Group 75% (3.19 ± 0.66, p < 0.0001). CONCLUSIONS: The image quality of CCTA in Target CTA mode was significantly better when the center of acquisition window is adjusted using CS.

[TYPING OF MYCOBACTERIUM TUBERCULOSIS STRAINS IN FUKUOKA PREFECTURE, JAPAN, USING 24-LOCUS VARIABLE-NUMBER TANDEM-REPEAT TYPING].

[Aim] To determine genotypes of Mycobacterium tuberculosis strains in Fukuoka Prefecture, Japan. [Methods] A total of 296 isolates from 296 tuberculosis patients is tested using 24-locus variable-number tandem- repeat (VNTR) typing. We also determined whether these isolates and a further 10 were Beijing lineage. [Results] The 296 isolates were classified into 264 VNTR types, and re-classified into 25 clusters when each cluster was defined as isolates being identical to VNTR types in 24 regions, or in 23 regions with the exception of one hypervariable region. Two clusters were shown to be identical to that of the Kansai regional epidemic. Regarding regional diversity, hypervariable regions showed relatively higher variation of isolate types. The Beijing lineage accounted for 78.1% of all isolates, which was similar to the value obtained from Kobe (78.5% in 2009) in the Kansai region. [Discussion] Six isolates from Fukuoka Prefecture over- lapped with those from Kansai region with respect to domi- nant VNTR type, while clusters from Fukuoka Prefectural isolates were unique, which may be a feature of Fukuoka prefectural isolates. [Conclusion] These data are likely to be useful for public health measures in the area.

Environmental surveillance of poliovirus in sewage water around the introduction period for inactivated polio vaccine in Japan.

Environmental virus surveillance was conducted at two independent sewage plants from urban and rural areas in the northern prefecture of the Kyushu district, Japan, to trace polioviruses (PVs) within communities. Consequently, 83 PVs were isolated over a 34-month period from April 2010 to January 2013. The frequency of PV isolation at the urban plant was 1.5 times higher than that at the rural plant. Molecular sequence analysis of the viral VP1 gene identified all three serotypes among the PV isolates, with the most prevalent serotype being type 2 (46%). Nearly all poliovirus isolates exhibited more than one nucleotide mutation from the Sabin vaccine strains. During this study, inactivated poliovirus vaccine (IPV) was introduced for routine immunization on 1 September 2012, replacing the live oral poliovirus vaccine (OPV). Interestingly, the frequency of PV isolation from sewage waters declined before OPV cessation at both sites. Our study highlights the importance of environmental surveillance for the detection of the excretion of PVs from an OPV-immunized population in a highly sensitive manner, during the OPV-to-IPV transition period.

The effect of expert knowledge on medical search: medical experts have specialized abilities for detecting serious lesions.

How does domain-specific knowledge influence the experts' performance in their domain of expertise? Specifically, can visual search experts find, with uniform efficiency, any type of target in their domain of expertise? We examined whether acquired knowledge of target importance influences an expert's visual search performance. In some professional searches (e.g., medical screenings), certain targets are rare; one aim of this study was to examine the extent to which experts miss such targets in their searches. In one experiment, radiologists (medical experts) engaged in a medical lesion search task in which both the importance (i.e., seriousness/gravity) and the prevalence of targets varied. Results showed decreased target detection rates in the low prevalence conditions (i.e., the prevalence effect). Also, experts were better at detecting important (versus unimportant) lesions. Results of an experiment using novices ruled out the possibility that decreased performance with unimportant targets was due to low target noticeability/visibility. Overall, the findings suggest that radiologists do not have a generalized ability to detect any type of lesion; instead, they have acquired a specialized ability to detect only those important lesions relevant for effective medical practices.

Abnormal signal intensities of the seminal vesicles in a screening population.

PURPOSE: To investigate the incidence of abnormal signal hyperintensity on T1-weighted magnetic resonance imaging (MRI) of the seminal vesicles in a screening population in order to compare clinical indicators between subjects with and without signal abnormality. MATERIALS AND METHODS: Signal intensity of the seminal vesicles on T1-weighted images and clinical examinations were investigated in 3570 examinations of 1865 male subjects (mean age 54.8 years, range 23-86 years at the first examination). RESULTS: Abnormal signal hyperintensity was observed at least once in 32 subjects (1.7%). Subjects with the abnormality were significantly older (average age with and without the abnormality, 64.1 vs. 54.6, respectively, P < 0.001), and the incidence of abnormality increased with increasing age (0% for the age group <40, 0.3% for 40-49, 1.3% for 50-59, 2.9% for 60-69, 5.9% for 70-79, and 10.1% for >80). No significant difference was found in clinical indicators except for serum creatinine (1.10 vs. 0.84 mg/dL, P < 0.001). Of 12 subjects with abnormal signal intensity and follow-up data, the finding persisted on the same side for at least 11 months in seven subjects (58%). CONCLUSION: Abnormal signal intensity of the seminal vesicles was observed in 1.7% of screening population, and the imaging finding in isolation is unlikely to have clinical significance.

Virulence gene profiles and population genetic analysis for exploration of pathogenic serogroups of Shiga toxin-producing Escherichia coli.

Infection with Shiga toxin (Stx)-producing Escherichia coli (STEC) is a serious public health concern, causing severe diarrhea and hemolytic-uremic syndrome. Patient symptoms are varied among STEC strains, possibly implying the presence of markers for STEC virulence other than Stx. To reveal the genotypic traits responsible for STEC virulence, we investigated 282 strains of various serogroups for the presence of 17 major virulence genes, i.e., stx1, stx2a, stx2c, stx2d, stx2e, stx2f, eae, tir, espB, espD, iha, saa, subA, ehxA, espP, katP, and stcE. Next, we examined the prevalence of virulence genes according to the seropathotypes in which serotypes were classified (seropathotypes A through E) based on the reported frequencies in human illness, as well as known associations with outbreaks and with severe disease. Our results demonstrate that the presence of both katP and stcE in STEC, in addition to the genes located in the locus of enterocyte effacement (LEE), including eae, tir, espB, and espD, may indicate the most pathogenic genotype of STEC. A population structure analysis of the profiles of virulence genes statistically supported the pathogenic genotype and, furthermore, revealed that there are serogroups with potentially higher pathogenicity than previously thought. Some strains in serogroups O26, O145, and O165 may have high virulence equivalent to that of serogroup O157. Several serogroups, including O14, O16, O45, O63, O74, 119, O128, and O untypeable, also may be potentially pathogenic, although rarely in humans.

Peritoneal fluid accumulation in healthy men and postmenopausal women: evaluation on pelvic MRI.

OBJECTIVE: The purpose of this article is to investigate the prevalence, volume, and location of peritoneal fluid accumulation and to clarify the clinical significance of a small amount of peritoneal fluid accumulation in healthy men and postmenopausal women on pelvic MRI. MATERIALS AND METHODS: Pelvic MRI was performed on 1017 healthy men and 310 healthy postmenopausal women. Two radiologists independently interpreted images and judged the presence or absence of fluid in the peritoneal cavity. For cases in which peritoneal fluid was detected, the volume and the location were recorded. RESULTS: Peritoneal fluid was identified in 39 of 1017 (3.8%) healthy men and 52 of 310 (16.8%) healthy postmenopausal women. Healthy postmenopausal women had a much higher prevalence than did healthy men (p < 0.0001). The mean (± SD) total volume of fluid accumulation was 3.0 ± 2.7 mL in healthy men and 2.3 ± 2.0 mL in postmenopausal women. The volume of total peritoneal fluid was less than 10 mL in all but one man, who had 10.3 mL of peritoneal fluid accumulation. Peritoneal fluid accumulation was located below the level of the S3 vertebra in all subjects. CONCLUSION: A small amount of peritoneal fluid accumulation is occasionally observed in healthy men and postmenopausal women on pelvic MRI. Pelvic peritoneal fluid accumulation of less than 10 mL is not considered to be of clinical significance in men and postmenopausal women.

Visualization of bile movement using MRI spin-labeling technique: preliminary results.

OBJECTIVE: The purpose of this article is to noninvasively visualize intrabiliary bile movement using an MRI spin-labeling technique and administration of water, full-fat milk, and negative contrast agent as stimuli for bile excretion. SUBJECTS AND METHODS: Six healthy volunteers underwent three studies with each of three oral liquid agents (water, full-fat milk, and manganese chloride solution) for a total of 18 MRI studies. Oblique-coronal T2-weighted images of the common bile duct were acquired at an inversion time of 1500 milliseconds after pulse labeling using a spin-labeling technique with an inversion pulse, repeated at intervals of 22 seconds. Bile flow rate was measured before and for 50 minutes after administration of the oral liquid agents, and its correlation with the change in gallbladder volume was assessed. RESULTS: Both anterograde and retrograde intermittent bile movements were successfully visualized in the common bile duct. The summation of excreted bile volume calculated from spin-labeled images correlated significantly with a decrease in gallbladder volume (p = 0.011). Milk stimulated significantly prolonged bile flow; flow was momentary with manganese chloride and mild with water; however, gallbladder volume decreased only in milk studies (p = 0.003). Biliary flow early after oral intake correlated significantly with gallbladder contractility at 50 minutes after oral intake (p = 0.049). CONCLUSION: A new method for visualizing intrabiliary bile movement in semi-real time (22-second time resolution) using an MRI spin-labeling technique was proposed. Bile was shown to be excreted in a to-and-fro type of movement. Administration of water and negative contrast agent may induce temporary bile excretion.

Santorinicele without pancreas divisum pathophysiology: initial clinical and radiographic investigations.

BACKGROUND: Only one case of santorinicele without pancreas divisum pathophysiology (SWOPP) was previously reported. The purpose of the study was to determine the gross prevalence of SWOPP and santorinicele with pancreas divisum (SWPD) in community and patient populations, and investigate their clinical and radiographic features. METHODS: This cross-sectional study was performed at a tertiary referral centre. The Patient group comprised 2035 consecutive patients enrolled in the study who underwent magnetic resonance cholangiopancreatography (MRCP) studies. The Community group comprised 2905 consecutive subjects who participated in our whole-body medical check-up program that routinely includes MRCP studies. SWOPP was diagnosed when a saccular dilatation of the terminal portion of the dorsal pancreatic duct was observed unaccompanied by pancreas divisum or dominant dorsal duct. The prevalence of SWOPP and SWPD, and the clinical and radiological features were assessed in each group. RESULTS: Five cases of SWOPP were found in the Patient group (age range, 67-85 years; mean age, 73.6 years) (5/2035 = 0.25%; 95% confidence interval, 0.07-0.57); there were no cases of SWOPP in the Community group (0/2905 = 0.00%; 95% confidence interval, 0.00-0.10) (P = 0.01). Previous history of pancreatitis (4/5) and chronic pancreatitis (3/5) was more common in patients with SWOPP than in other subjects in the Patient or Community groups (both P < 0.05). Two cases of SWOPP were accompanied by reverse-Z type meandering main pancreatic duct. Six cases of SWPD were found. These cases were asymptomatic in 4/6, had a larger santorinicele (6.9 mm) than SWOPP patients (4.5 mm; P = 0.02), and were not associated with pancreatitis (0/6). CONCLUSIONS: The second to sixth reported cases of SWOPP were presented. SWOPP is a relatively rare condition found mostly in patients suffering pancreatitis, especially chronic pancreatitis, and may be an acquired condition. Santorinicele is not always accompanied by pancreas divisum.

Gene and cytokine profile analysis of macrolide-resistant Mycoplasma pneumoniae infection in Fukuoka, Japan.

BACKGROUND: Recent epidemiologic data suggest that the prevalence of macrolide resistant Mycoplasma pneumoniae (MR-M. pneumoniae) is increasing rapidly worldwide. This study assessed the present status of M. pneumoniae infection in Japan and clinical end-points to distinguish children with MR-M. pneumoniae. METHODS: During an outbreak of M. pneumoniae infections in Fukuoka, Japan in 2010-11, a total of 105 children with clinically suspected M. pneumoniae infection were enrolled. M. pneumoniae was analyzed for macrolide resistance in domain V of the 23S rRNA gene. Sixty -five patients with PCR positive for M. pneumoniae were analyzed with regard to clinical symptoms, efficacy of several antimicrobial agents and several laboratory data. RESULTS: Causative pathogens were detected in 81.0% (85 of 105) and M. pneumoniae was identified 61.9% (65 of 105). The resistance rate of M. pneumoniae was 89.2% (58 of 65) in this general pediatric outpatient setting. Patients infected with MR-M. pneumoniae showed longer times to resolution of fever and required frequent changes of the initially prescribed macrolide to another antimicrobial agent. We observed three different genotypes of M. pneumoniae including the rarely reported A2063T mutation (A2063G: 31 strains, A2063T: 27 strains, no mutation: 7 strains). Drug susceptibility testing showed different antimicrobial susceptibility profiles for each genotype. Serum IFN-gamma, IL-6 and IP-10 levels were higher in patients with MR-genotypes than in those infected with no-mutation strains (p < 0.001). CONCLUSIONS: Macrolide resistance is more common than previously thought and a small epidemic of rarely reported A2063T mutation was observed in Fukuoka, Japan. Furthermore our results reveal the possibility that levels of certain inflammatory cytokines may be a candidate to predict MR-M.pneumoniae infection.

Swallowing computed tomography and virtual reality as novel imaging modalities for the diagnosis of clicking larynx: Two case reports.

Globus sensation and pain causes are difficult to identify by conventional examination methods. With technology advances, new imaging methods including swallowing computed tomography (CT) and virtual reality (VR) have emerged and are contributing to definite diagnoses. We report two cases of cervical discomfort diagnosed as clicking larynx using swallowing CT/VR . Case 1 is a 55-year-old man. There were no findings on laryngoscopy or swallowing examinations, but swallowing CT/VR showed that the thyroid cartilage collided with the hyoid bone during swallowing, leading to the diagnosis of a clicking larynx. The patient was obese and is under observation hoping that weight loss will improve symptoms. Case 2 is a 32-year-old transgender man. He is receiving male hormones for gender identity disorder. He was diagnosed with a clicking larynx using swallowing CT/VR. Hormonal therapy may have increased the size of the thyroid cartilage, likely causing the symptoms. As they didn't choose surgical treatment, no symptomatic relief was achieved, but identifiying the cause contributed to improved patient satisfaction. Swallowing CT/VR is useful not only for evaluating the swallowing function, but also the underlying etiology of globus sensation and pain upon swallowing. Further clinical applications of this technique are expected for motion induced cervical symptoms.

Pancreas divisum as a predisposing factor for chronic and recurrent idiopathic pancreatitis: initial in vivo survey.

BACKGROUND: It is a controversial issue whether pancreas divisum (PD) induces pancreatitis. All previous studies have investigated this issue based on endoscopic procedures, which inevitably involve a selection bias. OBJECTIVES: To determine the unbiased prevalence rate of PD in a community population and to investigate the effect of PD on idiopathic pancreatitis using a non-invasive magnetic resonance (MR) technique. DESIGN: Cross-sectional study. PATIENTS: The study enrolled 504 subjects from the community who participated in the medical check-up programme and 46 patients with idiopathic pancreatitis (8 acute, 23 chronic, 15 recurrent) extracted from 70,122 consecutive MR studies performed at an academic tertiary care hospital. INTERVENTIONS: All subjects underwent magnetic resonance (MR) scanning and medical examination. MAIN OUTCOME MEASURES: Statistical comparison between subjects from the community and patients with idiopathic pancreatitis was made for the rate of PD (and its subtypes: classical PD, PD with absent ventral duct, and incomplete PD), MR findings, and clinical features. RESULTS: Multiple logistic regression analysis revealed PD as a significant factor that induces pancreatitis (OR 23.4; p<0.0001). The PD rate was significantly higher for all/chronic/recurrent idiopathic pancreatitis patients (35%/43%/33%; p<0.001 for all) than for subjects in the community group (2.6%), but was not higher for acute pancreatitis (13%; p=0.357). All PD subtypes were indicated to induce idiopathic pancreatitis but showed different associations with each onset type of pancreatitis. CONCLUSIONS: This is the first study to describe the prevalence of PD and PD subtypes in a community population and their association with idiopathic pancreatitis in vivo based on the findings of non-invasive MR and with minimal selection bias. It is concluded that PD should be considered a predisposing factor for chronic and recurrent pancreatitis.

Detection of left ventricular dysfunction on axial non-contrast chest CT.

PURPOSE: To evaluate the performance of axial non-contrast CT images in detecting systolic and diastolic left ventricular (LV) dysfunction. METHOD: This single-center retrospective study assessed 178 participants who underwent transthoracic ultrasonography and had non-contrast chest CT data within three months of ultrasonography. The patients were divided into LV systolic dysfunction (<52% ejection fraction in men and <54% in women), LV diastolic dysfunction (at least three of the following four criteria were met: average E/e' ratio >14; septal e' <7 cm/s or lateral e' <10 cm/s; peak tricuspid regurgitation velocity >2.8 m/s; or left atrial maximum volume index >34 ml/m2), and normal LV function groups. CT parameters were evaluated as predictive factors for LV dysfunction. These parameters were: I, maximum minor axis diameter of the LV lumen; II, I plus myocardial wall thickness; III, maximum left atrium anteroposterior diameter; IV, maximum transverse cardiac diameter; V, myocardial wall thickness; I-IV divided by maximum medial thoracic diameter; and I-IV divided by anteroposterior thoracic diameter. All parameters were measured on axial images: diameters were maximized. RESULTS: LV systolic dysfunction was indicated when parameter IV exceeded 131.2 mm with sensitivity and specificity of 71.8% and 77.0%, respectively. Moreover, LV diastolic dysfunction was indicated when parameter III divided by anteroposterior thoracic diameter exceeded 0.165 with sensitivity and specificity of 77.8% and 83.0%, respectively. CONCLUSIONS: Axial non-contrast chest CT is useful for detecting LV dysfunction. Even CT scans for other purposes provide LV function information that may lead to appropriate examination.