Reliability and Agreement in the Cerebellar Tonsil Tip Localization: Two Methods Using the McRae Line Concept in MRI.

BACKGROUND: The cerebellar tonsil tip position (TP) is a common parameter used for the radiologic diagnosis of Chiari malformation type 1 (CM1). However, these paramedian structures are usually not properly visualized in the midsagittal section. Such mismatch may be a source of bias in TP measurements based on the McRae line (ML) traced between median craniometric points. This study aims to evaluate the intraoperator and interoperator reliability and agreement of 2 protocols to trace the ML in magnetic resonance imaging (MRI) for the cerebellar tonsil tip localization, adding a 3-dimensional multiplanar reconstruction (MPR) approach to the midsagittal plane. METHODS: Sixty-two T1-weighted head MRIs were obtained for 32 CM1 patients and 30 controls. Two operators independently applied 2 TP measurement protocols, one considering only the visualization of the sagittal plane and the other using MPR. The intraclass correlation coefficient was used to assess intraoperator and interoperator reliability, and the Bland-Altman graphical method was used to evaluate the agreement between the measurement protocols. RESULTS: The sagittal method significantly underestimated ML and tonsillar herniation when compared with the MPR method. The MPR method provided better reliability of the ML measurement when compared to the sagittal method, but this did not influence the reliability of the TP. Analysis of the Bland-Altman plot showed that the limits of agreement were close to acceptable for the ML, but not for measures of TP. CONCLUSIONS: The standardization of the LM tracing by the MPR method improves the acquisition of data regarding the position of the tonsils.

Investigating Type B Basilar Invagination Through Cephalic Indices.

OBJECTIVE: We sought to compare the diagnostic accuracy of cephalic indices for type B basilar invagination (BI). METHODS: This retrospective study examined head and neck magnetic resonance imaging sequences of 31 Group B BI cases and 96 controls. Two examiners blinded to diagnostic data evaluated the cephalic indices of each magnetic resonance imaging sequence, described as width/length (WLI) and height/width (HWI). The distance of the odontoid process apex to Chamberlain line and clivus canal angle were measured. The interexaminer and intraexaminer reproducibility of the cephalic indices was calculated using intraclass correlation coefficient. The diagnostic accuracy was discerned by the receiver operating characteristic (ROC) curve. All analyses were scrutinized with a 95% confidence interval. RESULTS: Cephalic indices showed interexaminer and intraexaminer reproducibility ≥94%. The areas under the ROC curve were 0.639 (WLI) and 0.874 (HWI) (95% confidence interval: P < 0.05). The HWI showed a sensitivity of 74.7% and a specificity of 85.5% for the cutoff criterion ≤58. The WLI presented a sensitivity of 53.3% and a specificity of 66.7% for the cutoff criterion ≥86. CONCLUSIONS: The HWI showed the largest area under the ROC curve in comparison with the WLI, with robust sensitivity and specificity values, indicating that the proportions between cranial height and width can help clinicians in investigating type B BI.

Foramen Magnum Angle: A New Parameter for Basilar Invagination of Type B.

OBJECTIVE: To describe the foramen magnum angle (FMA) as a new parameter for basilar invagination (BI) type B. METHODS: The FMA was performed on sagittal slice of magnetic resonance imaging (MRI) as a line from the hard palate to the opisthion (angle vertex), and another line from the opisthion to the basion. The MRIs from 31 participants with BI type B and 96 controls were used. Intraclass correlation coefficient, descriptive data, and receiver operating characteristic (ROC) curve were used for statistical analysis at the 95% confidence interval. RESULTS: The interobserver agreement of the FMA was 0.952. Patients with BI type B had a FMA significantly greater (25.9° ± 9.3°) than control participants (11.6° ± 4.9°) (P < 0.001). The area under the ROC curve showed a diagnostic value of 0.947. The FMA showed sensitivity 0.900 and specificity 0.854 for the cutoff criterion 17° (P < 0.001). CONCLUSIONS: The FMA had an optimal diagnostic value that provided complementary evidence to investigate BI type B.

Is Basilar Invagination Related with Stenosis of the Hypoglossal Nerve Canal?

OBJECTIVE: To analyze the association between basilar invagination (BI) and stenosis in the hypoglossal canal (HC). METHODS: A case-control study with magnetic resonance images (MRIs) of the head from a local database was performed. The study used MRIs of 31 patients with BI (type B) and 36 controls, both groups over 18 years of age and without sex distinction. The internal (ID) and external (ED) diameters of the HC were measured on the coronal plane using the Osirix in its free version 3.9.2 (Mac-Apple platform). We used the Kolmogorov-Smirnov test (with Lilliefors adjustment) to evaluate the normality of the variables, the Levine test to verify the homogeneity of the variances, and Student's t test to verify differences between groups. All analyses were within the 95% confidence interval. RESULTS: Control group presented right and left ED values of 4.7 ± 0.8 mm and 4.6 ± 0.9 mm, respectively, while the right and left ID showed 4.4 ± 0.9 mm and 4.3 ± 0.8 mm, respectively. The group with BI showed right and left ED values of 3.3 ± 0.9 mm and 3.1 ± 0.9 mm, and the right and left ID had values of 2.8 ± 0.7 mm and 2.7 ± 0.7 mm, respectively. Both ED and ID were smaller in the group with BI (P < 0.001). CONCLUSIONS: Patients with BI of type B presented the narrowing of HC when compared with control participants.

Towards an Information Infrastructure for Medical Image Sharing.

Information infrastructures involve the notion of a shared, open infrastructure, constituting a space where people, organizations, and technical components associate to develop an activity. The current infrastructure for medical image sharing, based on PACS/DICOM technologies, does not constitute an information infrastructure since it is limited in its ability to share in a scalable, comprehensive, and secure manner. This paper proposes the DICOMFlow, a decentralized, distributed infrastructure model that aims to foment the formation of an information infrastructure in order to share medical images and teleradiology. As an installed base, it uses the PACS/DICOM infrastructure of radiology departments and the internet e-mail infrastructure. Experiments performed in real and simulated environments have indicated the feasibility of the proposed infrastructure to foment the formation of an information infrastructure for medical image sharing and teleradiology.

Diagnostic accuracy of classical radiological measurements for basilar invagination of type B at MRI.

OBJECTIVE: To evaluate the diagnostic accuracy of classical measurements for basilar invagination (BI) of type B at MRI. METHODS: This study used head MRIs from 31 participants with BI type B and 96 controls. The radiological criterion for BI was the odontoid process invagination using the obex as reference. It based on the independent prospective reading of two neuroradiologists. Concordance between the two neuroradiologists was analysed through the KAPPA index, and the discrepancy was resolved in a consensus meeting. A third examiner measured in two occasions (double blind) the distance of the odontoid apex to Chamberlain's line (DOCL) and McGregor's line (DOMG), clivus canal angle (CCA), Welcker's basal angle (WBA), and Boogaard's angle (BOA). Intra-examiner reproducibility of the measurements was evaluated with the intraclass correlation coefficient and the diagnostic accuracy by ROC curve. All analyses were at 95% confidence interval. RESULTS: Agreement between the two neuroradiologists was statistically relevant (KAPPA = .91; P = .0001). The intra-examiner reproducibilities were .98 (DOCL), .97 (DOMG), .96 (CCA), .94 (WBA), and .95 (BOA) (P < .05). The areas under the ROC curve were .963 (DOCL), .940 (DOMG), .880 (CCA), .867 (WBA), and .951 (BOA) (P < .05). The cut-off criteria were ≥ 7 mm (DOCL), ≥ 8 mm (DOMG), ≤ 145° (CCA), ≥ 142° (WBA), and ≥ 136° (BOA). The diagnostic accuracies were .904 (DOCL), .870 (DOMG), .844 (CCA), .810 (WBA), and .899 (BOA). CONCLUSION: The DOCL and BOA presented the highest diagnostic accuracy for BI type B. These slides can be retrieved under Electronic Supplementary Material.

Relationship between basilar invagination and brachycephaly in Northeastern Brazil.

BACKGROUND: Basilar invagination (BI) is an abnormality characterized by a superior projection at the craniovertebral junction (CVJ). The high prevalence of BI in Northeastern Brazil associated with brachycephaly, which is measured by the cranial index (CI), has been widely reported by several neurosurgeons and radiologists from that region since the 1950s. However, strong evidence for this relationship is still pending. The aim of this study is to investigate whether there is a relationship between BI and CI in a sample with participants from Northeastern Brazil. METHODS: The study used magnetic resonance images (MRIs) from 34 patients with BI and 92 controls. These participants had the CI correlated with radiological measurements used in BI diagnosis: Welcker's basal angle (WBA), clivus-canal angle (CCA), apex distance of the odontoid process to Chamberlain's line (DOCL), and Boogaard's angle (BOA). Craniometry was performed using the software Osirix, version 3.9.2 and statistical analysis by SPSS. We used Pearson's test for correlation analysis and the ROC curve was used for depicting CI accuracy related to BI diagnosis. All tests were calculated at the 95% confidence interval. RESULTS: The BI group showed a moderate correlation between CI and CVJ measurements (P < 0.05). The control group had a weak correlation between CI and DOCL, and no statistical significance was verified for other correlations (P > 0.05). The area under the ROC was 0.659 and a CI greater than 86 had a specificity of approximately 80% for BI (P = 0.002). CONCLUSIONS: The results indicated a greater cephalic projection of the CVJ in patients with high CI in the BI group. Moreover, a CI above 86 has a good diagnosis specificity for BI, showing evidence of a relationship between hyperbrachycephaly and CVJ anomalies in Northeastern Brazil.

Clinical progression of incidental tomographic findings in paranasal sinuses of asymptomatic individuals: cohort study.

OBJECTIVE: To determine whether the presence of opacification in the paranasal sinuses of children and adolescents without rhinosinusitis implies an increased risk of later development of upper respiratory tract symptoms. METHODS: This was a prospective study of a cohort of patients aged 0 to 18 years who underwent computerized tomography (CT) scans for indications unrelated to rhinosinusitis. Sinus opacification was evaluated using an opacification/development ratio score. The patients' clinical progression was followed up using a questionnaire for 1 month after the scans. RESULTS: Fifty-six percent (56%) of the 106 patients enrolled in the study had opacity, the majority due to mucosal thickening. Intense opacification was defined as "suspected" (score ≥ 15) and patients in this subset had a greater risk of developing symptoms during follow-up (odds ratio = 2.74; 95%CI 1.10-6.83) compared to those with no findings or discrete findings. CONCLUSIONS: Intense incidental sinus opacity on CT indicates a risk of future development of a clinical respiratory condition.

Evolução clínica de alterações tomográficas incidentais de seios paranasais em indivíduos assintomáticos: estudo de coorte / Clinical progression of incidental tomographic findings in paranasal sinuses of asymptomatic individuals: cohort study

OBJETIVO: Verificar se, em crianças e adolescentes sem rinossinusite, a presença de opacificações dos seios paranasais implica em maior risco de desenvolvimento posterior de sintomas do trato respiratório superior. MÉTODOS: Estudo prospectivo de coorte, com pacientes entre 0 e 18 anos, submetidos à tomografia computadorizada do crânio por indicações não relacionadas à rinossinusite. As opacificações sinusais foram aferidas pelo escore razão opacificação/desenvolvimento. A evolução clínica dos pacientes foi então avaliada por questionários durante o mês que se seguia ao exame. RESULTADOS: Dos 106 pacientes incluídos, as opacidades acometeram 56 por cento, a maioria de espessamento mucoso. Opacidades intensas, ditas suspeitas (escore > 15), impuseram maior risco de desenvolvimento de sintomas no seguimento (odds ratio = 2,74; IC95 por cento:1,10-6,83), em comparação aos exames normais ou às opacidades discretas. CONCLUSÃO: Opacidades tomográficas sinusais incidentais em crianças e adolescentes oferecem risco de desenvolvimento futuro de quadro clínico respiratório quando intensas.

OBJECTIVE: To determine whether the presence of opacification in the paranasal sinuses of children and adolescents without rhinosinusitis implies an increased risk of later development of upper respiratory tract symptoms. METHODS: This was a prospective study of a cohort of patients aged 0 to 18 years who underwent computerized tomography (CT) scans for indications unrelated to rhinosinusitis. Sinus opacification was evaluated using an opacification/development ratio score. The patients’ clinical progression was followed up using a questionnaire for 1 month after the scans. RESULTS: Fifty-six percent (56 percent) of the 106 patients enrolled in the study had opacity, the majority due to mucosal thickening. Intense opacification was defined as "suspected" (score > 15) and patients in this subset had a greater risk of developing symptoms during follow-up (odds ratio = 2.74; 95 percentCI 1.10-6.83) compared to those with no findings or discrete findings. CONCLUSION: Intense incidental sinus opacity on CT indicates a risk of future development of a clinical respiratory condition.