Changes in surgery rates among hospitalized patients with inflammatory bowel disease in Japan from 2015 to 2019: A nationwide administrative database analysis.

BACKGROUND AND AIM: Treatment of inflammatory bowel disease (IBD), consisting of ulcerative colitis (UC) and Crohn's disease (CD), has advanced with the application of biologics or Janus kinase inhibitor (JAKi); however, some patients still need surgery. We assessed time trends of surgery and biologics or JAKi variety in Japan. METHODS: Patients hospitalized due to IBD were analyzed using Diagnosis Procedure Combination data between 2015 and 2019. Longitudinal trend analysis was performed for demographics, and interrupted time-series analysis was performed to examine the association between surgery rates and an increase in the types of biologics or JAKi. RESULTS: Totally, 37 867 cases with UC and 35 493 cases with CD were analyzed. Over 5 years, the surgery rate decreased in both UC and CD. The proportion of biologics and JAKi usage increased in UC and stabilized in CD. Between decreasing surgery and expanding treatment options of biologic or JAKi, interrupted time-series analysis results showed no significant correlation (level change in UC, -1.13, 95% confidence interval [CI]: -2.11 to -0.16, P = 0.0235; slope change in UC, -0.05, 95% CI: -0.26 to 0.16, P = 0.6372; level change in CD, -0.55, 95% CI: -1.82 to 0.71, P = 0.3815; slope change in CD, -0.22, 95% CI: -0.63 to 0.19, P = 0.2892). CONCLUSIONS: In Japan, from 2015 to 2019, the use of biologics or JAKi increased for UC and slightly decreased for CD, while the number of surgeries decreased in both. Our findings suggest that more widespread use of biologics or JAKi therapy could reduce surgeries in patients with IBD.

Submandibular gland carcinoma ex pleomorphic adenoma with calcification.

We report an unusual case of carcinoma ex pleomorphic adenoma (CXPA) in the submandibular gland. The mass had a unique calcification. Panoramic tomography revealed sponge-like calcification. The central portion displayed heterogeneous high signal intensity on T1-weighted image (T1WI) and T2-weighted image (T2WI), and heterogeneously moderate signal intensity on a short-TI inversion recovery (STIR) image. The ADC was low (0.78 × 10-3mm2/sec). After surgical excision, a pathological examination revealed that the mass contained CXPA as a minor component. Tumor cells with large hyperchromatic nuclei and eosinophilic or clear cytoplasm proliferated in irregular small tubule formations or cribriform or Roman-bridge structures in hyalinized or focally ossified stroma. The entire mass was calcified, particularly in the central region. Taken together, the reduced T1 relaxation times were related to the surface effects of diamagnetic particles, which were observed at calcium particle concentrations of up to 30%. We report a CXPA with unusual sponge-like calcification, which appeared unusually hyperintense on T1WI due to a surface effect.

Anatomical characterization of athetotic and spastic cerebral palsy using an atlas-based analysis.

PURPOSE: To analyze diffusion tensor imaging (DTI) in two types of cerebral palsy (CP): the athetotic-type and the spastic-type, using an atlas-based anatomical analysis of the entire brain, and to investigate whether these images have unique anatomical characteristics that can support functional diagnoses. MATERIALS AND METHODS: We retrospectively analyzed the DTI of seven children with athetotic-type, 11 children with spastic-type, and 20 healthy control children, all age-matched. The severity of motor dysfunction was evaluated with the Gross Motor Function Classification System (GMFCS). The images were normalized using a linear transformation, followed by large deformation diffeomorphic metric mapping. For 205 parcellated brain areas, the volume, fractional anisotropy, and mean diffusivity were measured. Principal component analysis (PCA) was performed for the Z-scores of these parameters. RESULTS: The GMFCS scores in athetotic-type were significantly higher than those in spastic-type (P < 0.001). PCA extracted anatomical components that comprised the two types of CP, as well as the severity of motor dysfunction. In the athetotic group, the abnormalities were more severe than in the spastic group. In the spastic group, significant changes were concentrated in the lateral ventricle and periventricular structures. CONCLUSION: Our results quantitatively delineated anatomical characteristics that reflected the functional findings in two types of CP.

Quantification of white matter injury following neonatal stroke with serial DTI.

BACKGROUND: Diffusion tensor imaging (DTI) can be used to predict outcome following perinatal arterial ischemic stroke (PAIS), although little is known about white matter changes over time. METHODS: Infants with PAIS were serially scanned in the neonatal period (n = 15), at 3 mo (n = 16), and at 24 mo (n = 8). Fractional anisotropy (FA) values in five regions of interest (anterior and posterior limb of the internal capsule, corpus callosum, optic radiation, and posterior thalamic radiation) were obtained and compared with FA values of healthy controls and neurodevelopmental outcome. RESULTS: In the neonatal period, no differences in FA values were found. At 3 mo, the six infants who ultimately developed motor deficits showed lower FA values in all affected regions. Four infants developed a visual field defect and showed lower FA values in the affected optic radiation at 3 mo (0.22 vs. 0.29; P = 0.03). Finally, a correlation between FA values of the corpus callosum at 3 mo and the Griffiths developmental quotients was found (r = 0.66; P = 0.03). At 24 mo, a similar pattern was observed. CONCLUSION: Neonatal FA measurements may underestimate the extent of injury following PAIS. FA measurements at 3 mo could be considered a more reliable predictor of neurodevelopmental outcome and correlate with DTI findings at 24 mo.

Diffusion tensor imaging of normal brain development.

Diffusion tensor imaging (DTI) is an MRI technique that can measure the macroscopic structural organization in brain tissues. DTI has been shown to provide information complementary to relaxation-based MRI about the changes in the brain's microstructure. In the pediatric population, DTI enables quantitative observation of the maturation process of white matter structures. Its ability to delineate various brain structures during developmental stages makes it an effective tool with which to characterize both the normal and abnormal anatomy of the developing brain. This review will highlight the advantages, as well as the common technical pitfalls of pediatric DTI. In addition, image quantification strategies for various DTI-derived parameters and the normal brain developmental changes associated with these parameters are discussed.

CT findings of small bowel strangulation: the importance of contrast enhancement.

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.

Radiological diagnosis of large-bowel obstruction: neoplastic etiology.

Large-bowel obstruction (LBO) is a relatively common abdominal emergency. The CT exam has become the most important imaging modality for the diagnosis of LBO, following abdominal ultrasound and plain radiography. The recent multi-detector CT (MD-CT) is able to clarify the etiology of LBO and to help in deciding how to treat LBO. Therefore, it is important for the radiologists to become familiar with the imaging findings of LBO, including plain radiograph and CT, due to various causes. In this article, we have shown the characteristics of the radiological findings including plain radiograph, barium study, and CT as well as their correlations with pathologic findings of LBO. The etiology of LBO is usually divided into neoplastic diseases and nonneoplastic diseases. However, the most common cause is the neoplastic etiology. Now, we can afford the critical information concerning the level of obstruction, its cause, the viability of the involved bowel loops, and a decision-making regarding the therapy for patients with LBO, using MD-CT high technology.

[Multi-course web-learning system for supporting students of medical technology].

Web-Learning system was developed to support the self-learning for national qualification examination and medical engineering practice by students. The results from small tests in various situations suggest that the unit-learning systems are more effective, especially for the early stage of their self learning. In addition, the answers of some questionnaire suggest that the students' motivation has a certain relation with the number of the questions in the system. That is, the less number of the questions, the easier they are worked out with a higher learning motivation by students. Thus, the system was extended to enable students to study various subjects and/or units by themselves. The system enables them to have learning effects more easily by the exercise during lectures. The effectiveness of the system was investigated on medical associated subjects installed in the system. The concerning questions of Medical engineering and Pathological histology are adequately divided into several groups, of which sixteen Web-Learning subsystems were well composed for their practical application. Our concerning various unit-learning systems were confirmed much useful for most students comparing with the case of the overall Web-Learning system.

Macrocerebellum: significance and pathogenic considerations.

Macrocerebellum is a rare finding characterized by an abnormally large cerebellum. Only few patients with a syndromal or isolated macrocerebellum have been reported so far. This article aims to categorize the magnetic resonance imaging (MRI) findings, quantitate the macrocerebellum by volumetric analysis, characterize the neurological and dysmorphic features and cognitive outcome, and report the results of genetic analyses in children with macrocerebellum. All MR images were qualitatively evaluated for infratentorial and supratentorial abnormalities. Volumetric analysis was performed. Data about neurological and dysmorphic features, outcome, and genetic analysis were collected from clinical histories and follow-up examinations. Five patients were included. Volumetric analysis in three patients confirmed large cerebellar size compared to age-matched controls. MR evaluation showed that thickening of the cortical gray matter of the cerebellar hemispheres is responsible for the macrocerebellum. Additional infratentorial and supratentorial abnormalities were present in all patients. Muscular hypotonia, as well as impaired motor and cognitive development, was found in all patients, with ocular movement disorders in three of five patients. The five patients differed significantly in terms of dysmorphic features and involvement of extracerebral organs. Submicroscopic chromosomal aberrations were found in two patients. Macrocerebellum is caused by thickening of the cortical gray matter of the cerebellar hemispheres, suggesting that cerebellar granule cells may be involved in its development. Patients with macrocerebellum show highly heterogeneous neuroimaging, clinical, and genetic findings, suggesting that macrocerebellum is not a nosological entity, but instead represents the structural manifestation of a deeper, more basic biological disturbance common to heterogeneous disorders.

Influence of light dose on bond strength of orthodontic light-cured adhesives.

Although the polymerization reaction in light-cured orthodontic adhesive continues for some time after light irradiation, it is unclear whether insufficiently irradiated adhesive develops sufficient bond strength. This in vitro study examined the maturation of bond strength after exposure of a variety of light doses. Large metal brackets were bonded to the enamel of 288 bovine mandibular incisors by irradiation at two light intensities (200 and 400 mW/cm(2)) and for three exposure times (3, 5, and 10 seconds) using three orthodontic adhesives (TB, OP, and BOB). Shear bond strengths and adhesive remnant indices (ARIs) were determined immediately (T1) and 24 hours after bonding (T2; n = 8 in each group). Comparisons were made using the Kruskal-Wallis H-test, the Bonferroni-corrected Mann-Whitney U-test, and the Yates-corrected chi-square test. Bond strengths of the adhesives that showed maturation at low light intensity (200 mW/cm(2)) increased by 1.4- to 2.0-fold in 24 hours. An increase in exposure time increased bond strength more than did an increase in light intensity for most orthodontic adhesives. With an exposure time of 3 seconds at 200 mW/cm(2), the ARI scores of TB and OP differed significantly between T1 and T2. Thus, the most acceptable procedure when applying low-dose light intensity to a bracket before the placement of a wire is to increase the exposure time and/or wait for sufficient maturation of bond strength.

The Transoral Endoscope-Assisted Approach for Removal of a Dental Implant Displaced into the Maxillary Sinus: A Case Report and Review of the Literature.

Purpose: A dental implant displaced into the maxillary sinus can be removed transorally or transnasally. There is no report investigating any potential positional limitations by the transoral endoscope-assisted approach. The implant's location within the maxillary sinus was reviewed to clarify indications for this approach. Case report: A 36-year-old man was referred to us for removal of a dental implant displaced into the right maxillary sinus. The implant changed position preoperatively, but the transoral endoscope-assisted approach proved successful. Methods: A literature search through October 2020 was performed in PubMed for cases of implant removal from the maxillary sinus via transoral endoscope-assisted and transnasal endoscopic approaches. Results: Sixty-two prior cases were identified, 20 cases by the transoral endoscope-assisted approach and 43 cases by one or two transnasal endoscopic approaches, including one duplicate case. There were no cases in which the implant was not identified by the transoral endoscope-assisted approach, but two cases in which the implant had moved to an unfavorable location and was not identified by only the initial transnasal endoscopic approach. Conclusion: Clinicians can preferentially choose the transoral endoscope-assisted approach, considering the possibility of unfavorable repositioning of the displaced implant within the maxillary sinus.

Athetotic and spastic cerebral palsy: anatomic characterization based on diffusion-tensor imaging.

PURPOSE: To evaluate the anatomy of deep gray and white matter structures in children with athetotic cerebral palsy (CP) and those with spastic CP by using diffusion-tensor (DT) imaging and to investigate whether these types of CP have unique anatomic correlates that can support their diagnosis and prognosis. MATERIALS AND METHODS: This study was approved by the institutional review board of each participating institution, and written informed consent was obtained from the parents of each patient. DT imaging was used to retrospectively evaluate 19 children with clinically diagnosed athetotic CP (mean age, 3.4 years ± 3.3 [standard deviation]), 26 children with spastic CP (mean age, 3.3 years ± 3.2), and 31 healthy control subjects (mean age, 3.2 years ± 3.0). Fractional anisotropy (FA) and mean diffusivity (MD) were measured with a region of interest (ROI) method. The ROIs were drawn on bilateral deep gray and white matter structures, including projection fibers, association fibers, and commissural fibers. Statistical analysis was performed by using the Kruskal-Wallis test with Bonferroni correction. P < .05 indicated a significant difference. RESULTS: FA values in the athetotic CP group were significantly lower than those in the control and spastic CP groups for multiple structures, including deep gray and white matter (P < .05 and P = .0001, respectively); these differences were also associated with increasing MD (P < .05 and P < .001, respectively). On the other hand, in the spastic CP group, the significantly decreased FA values, compared with those of the normal group, were limited to several white matter structures (P < .05 and P = .0001). CONCLUSION: In children with athetotic CP, the extent of change on DT images due to early brain damage tends to be more diffuse, including multiple brain structures, compared with the changes in children with spastic CP.

Synthesis and structure of dawson polyoxometalate-based, multifunctional, inorganic-organic hybrid compounds: organogermyl complexes with one terminal functional group and organosilyl analogues with two terminal functional groups.

Four novel multifunctional polyoxometalate (POM)-based inorganic-organic hybrid compounds, [α(2)-P(2)W(17)O(61){(RGe)}](7-) (Ge-1, R(1) = HOOC(CH(2))(2(-)) and Ge-2, R(2) = H(2)C═CHCH(2(-))) and [α(2)-P(2)W(17)O(61){(RSi)(2)O}](6-) (Si-1, R(1) and Si-2, R(2)), were prepared by incorporating organic chains having terminal functional groups (carboxylic acid and allyl groups) into monolacunary site of Dawson polyoxoanion [α(2)-P(2)W(17)O(61)](10-). In these POMs, new modification of the terminal functional groups was attained by introducing organogermyl and organosilyl groups. Dimethylammonium salts of the organogermyl complexes, (Me(2)NH(2))(7)[α(2)-P(2)W(17)O(61)(R(1)Ge)]·H(2)O MeN-Ge-1 and (Me(2)NH(2))(7)[α(2)-P(2)W(17)O(61)(R(2)Ge)]·4H(2)O MeN-Ge-2, were obtained as analytically pure crystals, in 22.8% and 55.3% yields, respectively, by stoichiometric reactions of [α(2)-P(2)W(17)O(61)](10-) with separately prepared Cl(3)GeC(2)H(4)COOH in water, and H(2)C═CHCH(2)GeCl(3) in a solvent mixture of water/acetonitrile. Synthesis and X-ray structure analysis of the Dawson POM-based organogermyl complexes were first successful. Dimethylammonium salts of the corresponding organosilyl complexes, (Me(2)NH(2))(6)[α(2)-P(2)W(17)O(61){(R(1)Si)(2)O}]·4H(2)O MeN-Si-1 and (Me(2)NH(2))(6)[α(2)-P(2)W(17)O(61){(R(2)Si)(2)O}]·6H(2)O MeN-Si-2, were also obtained as analytically pure crystalline crystals, in 17.1% and 63.5% yields, respectively, by stoichiometric reactions of [α(2)-P(2)W(17)O(61)](10-) with NaOOC(CH(2))(2)Si(OH)(2)(ONa) and H(2)C═CHCH(2)Si(OEt)(3). These complexes were characterized by elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), FTIR, solid-state ((31)P) and solution ((31)P, (1)H, and (13)C) NMR, and X-ray crystallography.

Encapsulation of anion/cation in the central cavity of tetrameric polyoxometalate, composed of four trititanium(IV)-substituted α-Dawson subunits, initiated by protonation/deprotonation of the bridging oxygen atoms on the intramolecular surface.

Preparation and structural characterization of a novel polyoxometalate (POM), [(P(2)W(15)Ti(3)O(60.5))(4)(NH(4))](35-) 1, i.e., an encapsulated NH(4)(+) cation species in the central cavity of a tetramer (called the Dawson tetramer) constituted by trititanium(IV)-substituted α-Dawson POM substructure, are described. POM 1 was synthesized by several different methods and unequivocally characterized by complete elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR spectroscopy, solution ((15)N{(1)H}, (31)P, (183)W) NMR spectroscopy, and X-ray crystallography. First, POM 1 was synthesized by a reaction of NH(4)Cl in aqueous solution with a precursor, which was derived by thermal treatment of a monomeric triperoxotitanium(IV)-substituted Dawson POM, [α-1,2,3-P(2)W(15)(TiO(2))(3)O(56)(OH)(3)](9-) 2, for 3 h in an electric furnace at 200 °C. The encapsulated NH(4)(+) cation in 1 was confirmed by (15)N{(1)H} NMR measurement and X-ray crystallography. As another synthesis of 1, a direct exchange of the Cl(-) anion encapsulated in [{α-1,2,3-P(2)W(15)Ti(3)O(57.5)(OH)(3)}(4)Cl](25-) 3 with the NH(4)(+) cation was attained by neutralizing an aqueous solution containing 3 with the addition of aqueous NH(3) (the initial pH of ca. 2-2.5 was changed to 6.4), followed by adding NH(4)Cl. It has been clarified that the conditions as to whether the anion or the cation is encapsulated in the central cavity of the Dawson tetramer were significantly related to the protonation/deprotonation of the bridging oxygen atoms on the intramolecular surface, Ti-O-Ti/Ti-OH-Ti sites constituting the Dawson subunits.

Expression of Neurokinin B Receptor in the Gingival Squamous Cell Carcinoma Bone Microenvironment.

Gingival squamous cell carcinoma (SCC) frequently invades the maxillary or mandibular bone, and bone destruction is known as a key prognostic factor in gingival SCCs. Recently, Neurokinin 3 receptor (NK-3R), the receptor ligand for NK-3, which is a member of the tachykinin family expressed in the central nervous system, was identified through pathway analysis as a molecule expressed in osteoclasts induced by the hedgehog signal. Although the expression of NK-3R has been detected in osteoclast and SCC cells at the bone invasion front, the relationship between NK-3R expression and the prognosis of gingival SCC patients remains unclear. In the present study, we retrospectively reviewed 27 patients with gingival SCC who had undergone surgery with curative intent. Significantly higher NK-3R expression in tumor cells was found in a case of jawbone invasion than in a case of exophytic poor jawbone invasion. On the other hand, no significant association was observed between NK-3R tumor-positive cases and tumor size, TNM stage, or tumor differentiation. The survival rate tended to be lower in NK-3R tumor-positive cases, but not significantly. However, the disease-specific survival rate was significantly lower in patients with a large number of NK-3R-positive osteoclasts than in those with a small number of them at the tumor bone invasion front. Our results suggest that NK-3R signaling in the gingival SCC bone microenvironment plays an important role in tumor bone destruction and should be considered a potential therapeutic target in advanced gingival SCC with bone destruction.

Quantitative diffusion tensor tractography of the motor and sensory tract in children with cerebral palsy.

AIM: the aim of this study was to compare the findings of quantitative diffusion tensor tractography of the motor and sensory tracts in children with cerebral palsy (CP) and typically developed comparison individuals, and also to evaluate the correlation with gross motor function. METHOD: thirty-four children with CP (mean age 2y 2.mo, SD 2y 0mo; 19 with spastic diplegia, eight with hemiplegia, six with spastic quadriplegia, and one with spastic triplegia) and 21 healthy comparison children (mean 2y 1.68mo, SD 2y 8.64mo) were evaluated. The distribution of Gross Motor Function Classification System (GMFCS) levels in the CP group was as follows: level I, 7; level II, 14; level III, 5; level IV, 3; and level V, 5. The following three diffusion tensor imaging (DTI) parameters including tractography were evaluated for each tract (corticospinal tract [CST] and posterior thalamic radiation [PTR]): number of fibres, tract-based fractional anisotropy, and region of interest (ROI)-based fractional anisotropy. We compared each value between the two groups, and correlated each value with the GMFCS level. RESULTS: the number of fibres and ROI-based fractional anisotropy values of both tracts were significantly lower in children with CP than in the comparison group (p<0.05-0.001). Additionally, there was significant negative correlation between GMFCS level and motor-sensory parameters (p<0.001-0.05). INTERPRETATION: DTI parameters of the CST and PTR in children with CP were significantly lower than in comparison children. In addition, these parameters were significantly correlated with GMFCS level.

Surgical resection for advanced bisphosphonate-related osteonecrosis of the jaw associated with fibrous dysplasia: a case report.

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is an adverse drug reaction represented by destruction and/or death of bone. Fibrous dysplasia (FD) is a rare bony disorder characterised by abnormal fibro-osseous tissue that has lowered resistance to infection. Effective treatments for BRONJ that follows FD are unclear. Here, we report that advanced BRONJ associated with FD was successfully treated by surgical resection. A 69-year-old woman, whose left maxillary bone showed a ground glass appearance on computed tomography (CT) images, was taking alendronate. At 1 year after teeth within the abnormal bone were extracted, exposed bone was observed in the extraction sites and CT images revealed separated sequestrums. Under the clinical diagnosis of Stage 2 BRONJ with FD, we performed not only sequestrectomy but also a partial resection of the FD. Thereafter, the healing was uneventful without recurrence. In conclusion, our case suggests that surgical resection is useful for advanced BRONJ associated with FD.

Gonadal sex differentiation and expression of Sox9a2, Dmrt1, and Foxl2 in Oryzias luzonensis.

Oryzias luzonensis is closely related to the medaka, O. latipes. The sex of both species is determined by an XX-XY system. However, the testis determining gene (DMY/Dmrt1bY) found in O. latipes does not exist in O. luzonensis. Instead, a different gene is thought to act as a testis determining gene. In this study, we focused the gonadal sex differentiation process in O. luzonensis under different testis determining gene. First, we observed the gonadal development of O. luzonensis histologically. We then analyzed the expression of Sox9a2/Sox9b, Dmrt1, and Foxl2 during early development. Our results suggest that the sexual differentiation of germ cells in O. luzonensis is initiated later than in O. latipes. However, the timing of the sexual differentiation of the supporting cell linage is similar between the species.

Symmetrical central tegmental tract (CTT) hyperintense lesions on magnetic resonance imaging in children.

The central tegmental tract (CTT) is mainly the extrapyramidal tract connecting between the red nucleus and the inferior olivary nucleus. There are only a few case reports describing CTT abnormalities on magnetic resonance imaging (MRI) in children. Our purpose was to evaluate the frequency of CTT lesions and their characteristics on MRI, and to correlate the MR imaging findings with clinical features. We reviewed retrospectively the MR images of 392 children (215 boys and 177 girls) ranging in age from 1 to 6 years. To evaluate symmetrical CTT hyperintense lesions, we defined a CTT lesion as an area of bilateral symmetrical hyperintensity in the tegmentum pontis on both T2-weighted images and diffusion-weighted images in more than two slices. We measured the ADC (apparent diffusion coefficient) values of symmetrical CTT hyperintensity, and compared them with those of children without CTT abnormality. CTT lesions were detected in 20 (5.1%) of the 392 children. The mean ADC value for these 20 children was significantly lower than that of the normal CTT (p<0.001). On MR imaging, other than CTT lesions, associated parenchymal lesion included: none (n=6); other abnormalities, including periventricular leukomalacia (n=3); thin corpus callosum (n=3); ventricular dilatation (n=2); encephalopathy (n=2). Clinically, cerebral palsy was the most frequent clinical diagnosis (n=6), accounting for 30%, which was significantly more frequent than the prevalence of cerebral palsy among children without CTT lesions (13%) (n<0.05). CTT lesions were detected in 5.1% of all the children examined. Cerebral palsy was the most frequent clinical diagnosis.

Evaluation of cone-beam computed tomography diagnostic image quality using cluster signal-to-noise analysis.

OBJECTIVES: (1) We sought to assess correlation among four representative parameters from a cluster signal-to-noise curve (true-positive rate [TPR] corresponding to background noise, accuracy corresponding to background noise, maximum TPR, and maximum accuracy) and the diagnostic accuracy of the identification of the mandibular canal using data from observers in a previous study, under the same exposure conditions. (2) We sought to clarify the relationship between the hole depths of a phantom and diagnostic accuracy. METHODS: CBCT images of a Teflon plate phantom with holes of decreasing depths from 0.7 to 0.1 mm were analyzed using the FindFoci plugin of ImageJ. Subsequently, we constructed cluster signal-to-noise curves by plotting TPRs against false-positive rates. The four parameters were assessed by comparing with the diagnostic accuracy calculated from the observers. To analyze image contrast ranges related to detection of mandibular canals, we determined five ranges of hole depths, to represent different contrast ranges-0.1-0.7, 0.1-0.5, 0.2-0.6, 0.2-0.7 and 0.3-0.7 mm-and compared them with observers' diagnostic accuracy. RESULTS: Among the four representative parameters, accuracy corresponding to background noise had the highest correlation with the observers' diagnostic accuracy. Hole depths of 0.3-0.7 and 0.1-0.7 mm had the highest correlation with observers' diagnostic accuracy in mandibles with distinct and indistinct mandibular canals, respectively. CONCLUSIONS: The accuracy corresponding to background noise obtained from the cluster signal-to-noise curve can be used to evaluate the effects of exposure conditions on diagnostic accuracy.