Midsagittal MR Images Research Articles

Classification of Brain MR Images Using Corpus Callosum Shape Measurements

The corpus callosum is the largest white matter structure in the brain, which connects the two cerebral hemispheres and facilitates the inter-hemispheric communication. Abnormal anatomy of corpus callosum has been revealed for various brain related diseases. Being an important biomarker, Magnetic Resonance Imaging of the brain followed by corpus callosum segmentation and feature extraction has found to be important for the diagnosis of many neurological diseases. This paper focuses on classification of T1-weighted mid-sagittal MR images of brain for dementia patients. The corpus callosum is segmented using K-means clustering algorithm and corresponding shape based measurements are used as features. Based on these shape based measurements, a back-propagation neural network is trained separately for male and female dataset. The input data consists of 54 female and 31 male patients. This paper reports classification accuracy up to 92% for female patients and 94% for male patients using neural network classifier.

Tapering of the cervical spinal canal in patients with distended or non-distended syringes secondary to Chiari malformation type I

Methods and materials Seventy-seven patients were divided into two groups based on the syrinx/cord (S/C) ratio: one with distended syrinx (S/C ratio > 0.5) and the other with non-distended syrinx (S/C ratio < 0.5). Anteroposterior diameter of the spinal canal was measured at each cervical level on midsagittal T2-weighted MR images, and a linear trend line was ft by least-square regression to calculate the taper ratio. With the Kruskal-Wallis test, taper ratios were compared between the two groups and further evaluated with respect to age and gender.

Cranial base pathology in pediatric osteogenesis imperfecta patients treated with bisphosphonates.

Cranial base pathology is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze whether bisphosphonate treatment, used to improve bone strength, could also prevent the development of craniocervical junction pathology (basilar impression, basilar invagination, or platybasia) in children with OI. In this single-center retrospective study the authors analyzed the skull base morphology from lateral skull radiographs and midsagittal MR images (total of 94 images), obtained between the ages of 0 and 25 years in 39 bisphosphonate-treated OI patients. The results were compared with age-matched normative values and with findings in 70 OI patients who were not treated with bisphosphonates. In addition to cross-sectional data, longitudinal data were available from 22 patients with an average follow-up period of 7.6 years. The patients, who had OI types I, III, IV, VI, and VII, had been treated with zoledronic acid, pamidronate, or risedronate for 3.2 years on average. Altogether 33% of the 39 bisphosphonate-treated patients had at least 1 cranial base anomaly, platybasia being the most prevalent diagnosis (28%). Logistic regression analysis suggested a higher risk of basilar impression or invagination in patients with severe OI (OR 22.04) and/or older age at initiation of bisphosphonate treatment (OR 1.45), whereas a decreased risk was associated with longer duration of treatment (OR 0.28). No significant associations between age, height, or cumulative bisphosphonate dose and the risk for cranial base anomaly were detected. In longitudinal evaluation, Kaplan-Meier curves suggested delayed development of cranial base pathology in patients treated with bisphosphonates but the differences from the untreated group were not statistically significant. These findings indicate that cranial base pathology may develop despite bisphosphonate treatment. Early initiation of bisphosphonate treatment may delay development of craniocervical junction pathology. Careful followup of cranial base morphology is warranted, particularly in patients with severe OI.

Low-field MRI and multislice CT for the detection of cerebellar (foramen magnum) herniation in Cavalier King Charles Spaniels.

BackgroundCavalier King Charles Spaniels (CKCS) have a high prevalence of Chiari‐like malformation (CM). Herniation of the cerebellum into the foramen magnum is a key diagnostic feature for CM. Midsagittal MR images are the preferred technique for visualizing cerebellar herniation (CH).ObjectiveTo investigate whether CT can be used to diagnose CH.AnimalsFifteen client‐owned CKCS dogs referred for investigation of the brain and cranial cervical spine on MRI and CT.MethodsTwo reviewers retrospectively analyzed midsagittal T1WSE and T2WSE MR images and midsagittal pre‐ and postcontrast 2D multiplanar reformatted CT images from each dog for the presence of CH. And, if present, the length (mm, CHL) of the herniation was measured. The results were analyzed statistically.ResultsThere was no significant difference between the different observers and techniques for the detection of CH and measurement of CHL. Overall, the CHL was longer on the CT images.Conclusion and Clinical ImportanceBoth techniques are useful for detecting CH and measuring CHL. Because CHL does not have a known direct impact on the clinical presentation of CM, CT can be used as a diagnostic tool in a routine clinical practice for CM in CKCS when MRI is not available. We emphasize that MRI is the standard screening technique in CKCS for breeding purposes to detect the presence of CM and SM and, at the current time, CT cannot replace MRI.

Syrinx resolution is correlated with the upward shifting of cerebellar tonsil following posterior fossa decompression in pediatric patients with Chiari malformation type I.

Chiari malformation type I (CMI) is characterized by deformed hindbrain. This study aimed to quantitatively evaluate the alterations in position of hindbrain after Posterior fossa decompression (PFD), and to identify the factors associated with syrinx resolution in pediatric patients with CMI. Eighty-seven patients, aged from 5 to 18 years, who underwent PFD for CMI between September 2006 and September 2012 were retrospectively reviewed. On mid-sagittal MR images, the position of medulla oblongata and cerebellum was quantitatively evaluated preoperatively and at follow-up. The maximal syrinx/cord (S/C) ratio and syrinx length were also measured. Significant improvement of syrinx was defined as a more than 20 % decrease in maximal S/C ratio or length on follow-up MRI. Neurological deficits were found in 51 of the 87 patients preoperatively and 37 (72.4 %) of them obtained improvement of their symptoms at the last visit. Overall, upward shifting of the tip of cerebellar tonsil was observed in 66 (75.9 %) patients at the last follow-up. Moreover, the mean longitudinal distance of the tip of cerebella tonsil changed from 16.47 ± 5.00 to 13.89 ± 4.38 mm (P < 0.001) at final follow-up. Significant syrinx resolution was noticed in 79 (90.8 %) cases. Pointed cerebellar tonsils were found in 85 (97.7 %) of our patients preoperatively and 78 (91.8 %) of them acquired round cerebellar tonsils after PFD. The improvement of maximal S/C ratio was significantly correlated with upward shifting of the tip of cerebellar tonsil (P = 0.023). Following PFD for CMI, position and morphology of the cerebellar tonsil could revert to normal in most of the pediatric patients, and the upward shifting of the tip of cerebellar tonsil is significantly correlated with syrinx improvement. From this study, PFD without shunting may be effective for syrinx secondary to CMI in pediatric population.

The evolution of T2-weighted intramedullary signal changes following ventral decompressive surgery for cervical spondylotic myelopathy: Clinical article.

T2-weighted intramedullary increased signal intensity (ISI) on MRI in patients with cervical spondylotic myelopathy (CSM) appears to represent a wide spectrum of pathological changes that determine reversibility of cord damage. Although sharp T2-weighted ISI on preoperative imaging may correlate with poorer surgical outcomes, there are limited data on how these changes progress following surgery. In this study, the authors characterized pre-and postoperative ISI changes in patients undergoing surgery for CSM and studied their postoperative evolution in an attempt to quantify their clinical significance. The preoperative and postoperative MR images obtained in 56 patients who underwent oblique cervical corpectomy for CSM were reviewed, and the ISI was classified into 4 subtypes based on margins and intensity: Type 0 (none), Type 1 ("fuzzy"), Type 2 ("sharp"), and Type 3 ("mixed"). The locations of the ISI were further classified as focal if they represented single discrete lesions, multifocal if there were multiple lesions with intervening normal cord, and multisegmental if the lesions were continuous over more than 1 segment. The maximum craniocaudal length of the ISI was measured on each midsagittal MR image. The Nurick grade and Japanese Orthopaedic Association (JOA) score were used to assess clinical status. The mean duration of follow-up was 28 months. T2-weighted ISI changes were noted preoperatively in 54 patients (96%). Most preoperative ISI changes were Type 1 (41%) or Type 3 (34%), with a significant trend toward Type 2 (71%) changes at follow-up. Multi-segmental and Type 3 lesions tended to regress significantly after surgery (p = 0.000), reducing to Type 2 changes at follow-up. Clinical outcomes did not correlate with ISI subtype; however, there was a statistically significant trend toward improvement in postoperative Nurick Grade in patients with a > 50% regression in ISI size. In addition, patients with more than 18 months of follow-up showed significant regression in ISI size compared with patients imaged earlier. On logistic regression analysis, preoperative Nurick grade and duration of follow-up were the only significant predictors of postoperative improvement in functional status (OR 4.136, p = 0.003, 95% CI 1.623-10.539 and OR 6.402, p = 0.033, 95% CI 1.165-35.176, respectively). There is a distinct group of patients with multisegmental Type 3 intramedullary changes who show remarkable radiological regression after surgery but demonstrate a residual sharp focal ISI at follow-up. A regression of the ISI by > 50% predicts better functional outcomes. Patients with a good preoperative functional status remain the most likely to show improvement, and the improvement continues to occur even at remote follow-up. The clinical relevance of the quality of the T2-weighted ISI changes in patients with CSM remains uncertain; however, postoperative regression of the ISI change is possibly a more important correlate of patient outcome than the quality of the ISI change alone.

Computer aided diagnosis of degenerative intervertebral disc diseases from lumbar MR images

This paper presents a novel method for the automated diagnosis of the degenerative intervertebral disc disease in midsagittal MR images. The approach is based on combining distinct disc features under a machine learning framework. The discs in the lumbar MR images are first localized and segmented. Then, intensity, shape, context, and texture features of the discs are extracted with various techniques. A Support Vector Machine classifier is applied to classify the discs as normal or degenerated. The method is tested and validated on a clinical lumbar spine dataset containing 102 subjects and the results are comparable to the state of the art.

Topographic variations of the optic chiasm and the pituitary stalk: a morphometric study based on midsagittal T2-weighted MR images

This study was conducted to characterize topographic variations of the optic chiasm (OC) and the pituitary stalk (PS) in situ based on MR images. Normal T2-weighted midsagittal MR images were obtained in 157 children and 323 adults. The height of OC (PC) and the inclination angle of PS (PS-AP angle) were measured in each case. All chiasms were classified into prefixed, normal and postfixed types, and low, medium and high types, respectively. All stalks were performed classification (prefixed, centered and postfixed PS) and grading (Grade 1-3 according to the relationship between PS and the dorsum sellae), respectively. PC averaged 4.33±1.59mm. Adults had a greater PC (P=0.023) than children. There were 80 (16.7%) prefixed, 354 (73.8%) normal and 46 (9.6%) postfixed chiasms, and 112 (23.3%), 295 (61.5%) and 73 (15.2%) cases with low, medium and high OC, respectively. High OC was more frequent in adults than in children (P=0.001). The mean PS-AP angle of the whole group was 59.47±8.62º. Children had a greater PS-AP angle than adults (P=0.012). Adults had a greater percentage of postfixed (P=0.000) and grade 3 (P=0.000) PS than children, whereas centered (P=0.002) and grade 1 (P=0.001) PS were more prevalent in children than in adults. The classifications of OC and PS based on MR images reflect the topographic variations of their real position in vivo. It would be helpful to identify and characterize the anomalies involving OC and PS and understand the anatomical and physiological influence in pathological situations.

Pontine encephalocele and abnormalities of the posterior fossa following transclival endoscopic endonasal surgery

Transclival endoscopic endonasal surgery (EES) has recently been used for the treatment of posterior fossa tumors. The optimal method of reconstruction of large clival defects following EES has not been established. A morphometric analysis of the posterior fossa was performed in patients who underwent transclival EES to compare those with observed postoperative anatomical changes (study group) to 50 normal individuals (anatomical control group) and 41 matched transclival cases with preserved posterior fossa anatomy (case-control group) using the same parameters. Given the absence of clival bone following transclival EES, the authors used the line between the anterior commissure and the basion as an equivalent to the clival plane to evaluate the location of the pons. Four parameters were studied and compared in the two populations: the pontine location/displacement, the maximum anteroposterior (AP) diameter of the pons, the maximum AP diameter of the fourth ventricle, and the cervicomedullary angle (CMA). All measurements were performed on midsagittal 3-month postoperative MR images in the study group. Among 103 posterior fossa tumors treated with transclival EES, 14 cases (13.6%) with postoperative posterior fossa anatomy changes were identified. The most significant change was anterior displacement of the pons (transclival pontine encephalocele) compared with the normal location in the anatomical control group (p < 0.0001). Other significant deformities were expansion of the AP diameter of the pons (p = 0.005), enlargement of the fourth ventricle (p = 0.001), and decrease in the CMA (p < 0.0001). All patients who developed these changes had undergone extensive resection of the clival bone (> 50% of the clivus) and dura. Nine (64.3%) of the 14 patients were overweight (body mass index [BMI] > 25 kg/m(2)). An association between BMI and the degree of pontine encephalocele was observed, but did not reach statistical significance. The use of a fat graft as part of the reconstruction technique following transclival EES with dural opening was the single significant factor that prevented pontine displacement (p = 0.02), associated with 91% lower odds of pontine encephalocele (OR = 0.09, 95% CI 0.01-0.77). The effect of fat graft reconstruction was more pronounced in overweight/obese individuals (p = 0.04) than in normal-weight patients (p = 0.52). Besides reconstruction technique, other noticeable findings were the tendency of younger adults to develop pontine encephalocele (p = 0.05) and the association of postoperative meningitis with the development of posterior fossa deformities (p = 0.05). One patient developed a transient, recurrent subjective diplopia; all others remained asymptomatic. Significant changes in posterior fossa anatomy that have potential clinical implications have been observed following transclival transdural EES. These changes are more common in younger patients or those with meningitis and may be associated with BMI. The use of a fat graft combined with the vascularized nasoseptal flap appears to minimize the risk of pontine herniation following transclival EES with dural opening.

Corpus Callosum Atrophy in Patients with Hereditary Diffuse Leukoencephalopathy with Neuroaxonal Spheroids: An MRI-based Study

Hereditary diffuse leukoencephalopathy with neuroaxonal spheroids (HDLS) is an adult-onset white matter disease that presents clinically with cognitive, mental and motor dysfunction. Several autopsy reports have indicated that the corpus callosum (CC), the largest bundle of white matter, is severely affected in patients with HDLS. The aim of this study was to evaluate corpus callosum atrophy (CCA) quantitatively in HDLS patients. We assessed CCA in six genetically-proven HDLS patients (HDLS group), in comparison with that observed in 20 patients with vascular dementia (VaD group) and 24 age-matched patients without organic central nervous system (CNS) disease (non-CNS group). Using midsagittal MR images, five measurements of the CC were obtained: the width of the rostrum (aa'), body (bb') and splenium (cc'), the anterior to posterior length (ab) and the maximum height (cd). Next, the corpus callosum index (CCI) was calculated as (aa' + bb' + cc')/ab. All HDLS patients had white matter lesions in the CC and frontoparietal lobes on the initial MRI scans. Compared with that observed in the VaD and age-matched non-CNS groups, the CCI was significantly decreased in the HDLS group (with VaD group, p<0.01; with non-CNS group, p<0.01). This study showed significant atrophy of the CC in all HDLS patients on the initial MRI scans obtained 6-36 months after onset. We propose that the early appearance of CCA, frequently accompanied by high-intensity in the genu and/or splenium, on T2 images is an important diagnostic clue to HDLS.

Central region morphometry in a child brain; Age and gender differences

Data on central region morphometry of a child brain is important not only in terms of providing us with information about central region anatomy of the brain but also in terms of the help of this information for the plans to be applied in neurosurgery. In the present study, central region morphometry of a child brain in mid-sagittal MR images was analyzed in age and gender groups. Different points determined previously, commissura posterior0 (PC) and the distances between cerebral cortex point (VCS) vertical to commissura anterior- commissura posterior line, sulcus centralis (CS), sulcus marginalis (MS), and the angle (α) between CS-PC-MS were determined and measured together with difference of gender in three different age groups (aged 6-9, 10-13, and 14-17). Central region measures of the brains of boys aged 6-17 are higher than girls except for MS-PC distance. While VCS-PC, CS-PC, and MS-PC measures display a significant difference in the girls aged 14-17 when compared to the other age groups of 6-9 and 10-13 (P < 0.05), angle α is not significantly different in age and gender groups (P > 0.05). However, while VCS-PC, CS-PC and MS-PC distances show a significant increase in girls beginning from the age of 14, this increase is limited in boys. Morphometric differences observed in different age groups in boys and girls shall contribute our evaluation of the alterations in brain development in both of genders and shall be useful in preparation of surgical operation plans to be applied to the central region.

Three techniques for automatic extraction of corpus callosum in structural midsagittal brain MR images: Valley Matching, Evolutionary Corpus Callosum Detection and Hybrid method

Corpus callosum (CC) is an important structure for medical image registration. We propose three novel fully automated for the extraction of CC. Our first algorithm, Valley matching (VM), is based on fixed searched range in histogram processing and uses prior anatomical information for locating CC. The second one, Evolutionary CC Detection (ECD), based on genetic algorithm presents a new fitness function that uses anatomical ratios, instead of fixed prior knowledge without the need for preprocessing. The final one, called Evolutionary Valley Matching (EVM), takes advantages of the strong points of the first and second algorithms. The search space defined for ECD is reduced by VM which uses crowding method to find the peaks in the multi-modal histogram. Another important contribution of this study is that there is no existing method using genetic algorithm for extracting CC. Our proposed algorithms perform with the success rates up to 95.5%.

Simultaneous Localization of Lumbar Vertebrae and Intervertebral Discs With SVM-Based MRF

This paper presents a method for localizing and labeling the lumbar vertebrae and intervertebral discs in mid-sagittal MR image slices. The approach is based on a Markov-chain-like graphical model of the ordered discs and vertebrae in the lumbar spine. The graphical model is formulated by combining local image features and semiglobal geometrical information. The local image features are extracted from the image by employing pyramidal histogram of oriented gradients (PHOG) and a novel descriptor that we call image projection descriptor (IPD). These features are trained with support vector machines (SVM) and each pixel in the target image is locally assigned a score. These local scores are combined with the semiglobal geometrical information like the distance ratio and angle between the neighboring structures under the Markov random field (MRF) framework. An exact localization of discs and vertebrae is inferred from the MRF by finding a maximum a posteriori solution efficiently using dynamic programming. As a result of the novel features introduced, our system can scale-invariantly localize discs and vertebra at the same time even in the existence of missing structures. The proposed system is tested and validated on a clinical lumbar spine MR image dataset containing 80 subjects of which 64 have disc- and vertebra-related diseases and abnormalities. The experiments show that our system is successful even in abnormal cases and our results are comparable to the state of the art.

Spontaneous Migration of a Redundant Nerve Root Accompanied by Absorption of Lumbar Disk Herniation

A redundant nerve root is defined as a large, elongated and tortuous nerve root commonly associated with severe lumbar spinal canal stenosis. Elongation of nerve roots as a result of mechanical trapping at stenotic level is assumed to be a possible mechanism. Here we present a case in a patient who showed a redundant nerve root above the level of a lumbar canal stenosis caused by disk herniation and redundancy spontaneously migrating to a lower lumbar stenosis level accompanied by absorption of the herniated disk as shown by magnetic resonance imaging (MRI). A 67-year-old Japanese woman presented with bilateral thigh/leg pain and intermittent claudication. A midsagittal T2-weighted MR image of the lumbar spine revealed severe spinal canal stenosis at the L3-4 and L4-5 levels. At the L3-4 level, central disk herniation compressed the dural tube. An MR image revealed redundant nerve roots just cranial to the severely compressed L3-4 level. A follow-up MRI study revealed regression of disk herniation at the L3-4 level. In contrast, there was no significant change of the stenosis at the L4-5 level. Sagittal T2-weighted MR imaging at follow-up revealed redundant nerve roots just cranial to the L4-5 level, whereas the redundant nerve roots cranial to the L3-4 level had disappeared. The MRI findings of the present case support the "squeeze" hypothesis as causative of redundant nerve roots.

An articulatory and acoustic study of fricative consonants /s/ and /sh/ in normal and post-glossectomy speakers

Glossectomy is a surgical procedure to remove the cancerous tumor of the tongue. After the glossectomy, the tongue is sutured closed or a flap is inserted to reconstruct the tongue volume. As a result, the properties of the tongue are more or less affected by the surgery. The changes in the tongue properties may also affect the speech production abilities of the post-glossectomy speaker. This study examined the production of the fricative consonants /s/ and /sh/ in normal and post-glossectomy speakers. The data analyzed consisted of audio and magnetic resonance images from dozens of normal and glossectomy speakers. An acoustic analysis showed that the average centers of gravity of /s/ and /sh/ in glossectomy speakers are significantly lower than in normals. This difference may be explained by a more posterior constriction in glossectomees due to the surgery. Examination of the tongue shapes in midsagittal MR images showed that they tend to have more laminal /s/ than apical /s/. 3-D vocal tracts of /s/ and /sh/ were reconstructed for three glossectomy speakers whose /s/ and /sh/ cannot easily be discriminated in listening tests. Details of the 3-D vocal tract shapes, along with their acoustic implications, will be discussed for the glossectomy and normal speakers. [This research was supported by NIH R01 CA133015.]

Effect of Sagittal Alignment on Kinematic Changes and Degree of Disc Degeneration in the Lumbar Spine

Retrospective analysis using positional MRI. To determine the effects of total sagittal lordosis on spinal kinematics and degree of disc degeneration in the lumbar spine. Changes in sagittal lordosis alter the load on the spine and may affect spinal mobility. There is increasing recognition of the clinical impact that sagittal alignment has on back pain, especially its possible role in accelerating adjacent segment degeneration after spinal fusion. However, its relationship to segmental mobility and degeneration of the lumbar spine has yet to be determined. Four hundred and thirty patients who had low back pain with or without leg pain (241 males and 189 females) with a mean age of 42.98 years (range, 16-85 years) were included. Total sagittal lordosis (T12-S1) was divided into three groups; Group A: Straight or Kyphosis (<20°, n = 84), Group B: Normal lordosis (20-50°, n = 294), and Group C: Hyperlordosis (>50°, n = 52). The degree of disc degeneration was graded using midsagittal T2-weighted MR images. Segmental mobility, including translational motion and angular variation, was measured using positional MRI. Their relationship with total segmental lordosis was identified. When compared with group B, the segmental motion in group C tended to be lower at the border of lordosis and higher at the apex of lordosis, with a significant difference in angular motion at L2-L3. The contrary finding was identified in group A, which had a higher segmental motion at border segments and lower motion at apical segments of lordosis, with significant difference of translational motion at L3-L4 and angular motion at L1-L2. Apical segments contributed more, whereas border segments contributed less to the total angular mobility in more lordotic spines. The opposite was seen in more kyphotic spines. Disc degeneration tended to be greater at all levels in group C, and at L1-L2 and L5-S1 in group A. Changes in sagittal alignment may lead to kinematic changes in the lumbar spine. This may subsequently influence load bearing and the distribution of disc degeneration at each level. Sagittal alignment, disc degeneration, and segmental mobility likely have a reciprocal influence on one another.

Relationships Between Vocal Structures, the Airway, and Craniocervical Posture Investigated Using Magnetic Resonance Imaging

Traditional voice research focuses on the vocal tract, articulators, and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, and sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies. Using a cross-sectional study design, we obtained midsagittal MR images from 10 healthy adults (five males and five females) while at rest and breathing quietly. With reference points based on cephalometry, 17craniocervical, craniocaudal, and anteroposterior variables were chosen to describe craniofacial morphology, craniocervical posture, and airway dimensions. Relationships between variables were sought using Pearson's correlation coefficient. We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r>0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngealtube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base. Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importanceof considering vocal structures and the airway within this wider context if important information is not to be missed.

Prenatal MR imaging of Dandy-Walker complex: Midline sagittal area analysis

To measure the mid-sagittal areas of vermis (VA) and of posterior fossa (PFA) and determine their differences among fetuses with various Dandy-Walker (DW) entities and control subjects. We reviewed data in 25 fetal patients with a MR diagnosis of DW complex including hypoplastic vermis (HV), HV with rotation (HVR), and mega cistern magna (MCM), and in 85 fetal controls with normal CNS. PFA and VA of each subject were manually traced on mid-sagittal MR images. Regarding each of VA and PFA, after age correction, we determined statistically significant differences among HVR, HV, MCM, and control groups. The mean VA residue of MCM was greater than that of the control, which was in turn greater than those of HVR and HV. The mean PF residue of the control was smaller than all other groups. Fetuses with HVR or HV had smaller VA than fetuses with MCM or control subjects. Fetuses with MCM, HVR, or HV had larger PFA than control subjects. These results may be an early step leading to better understanding of the confusion about the PF anomalies in future.

A New Reference Line for the Brain CT: The Tuberculum Sellae-Occipital Protuberance Line is Parallel to the Anterior/Posterior Commissure Line

CT and MR imaging of the brain have diverged reference lines. Modified Talairach anterior/posterior commissure (ACPC) line is widely accepted as the standard for clinical brain MR imaging, while orbitomeatal line (OML) is used for CT. This study sought to determine an appropriate reference line for brain CT parallel to the ACPC line. We measured the angles between the ACPC line and the OML, the line connecting the tuberculum sellae and the internal occipital protuberance (TS-IOP line), and the line connecting the tuberculum sellae and the external occipital protuberance (TS-EOP line) on midsagittal brain MR images of 223 patients. In addition, with the hard palate as the basis, the angles to the ACPC line in the brain MR images and new reference line on the brain CT images from the same patient were measured, and the difference between the 2 angles was calculated in 30 patients. In the same method, the angles to the OML in the brain CT images and the ACPC line on the brain MR images were measured, and their difference was calculated in 30 patients. Then the 2 difference values were compared with verification of the new reference line. The angles between the ACPC line and both the TS-IOP line (0.0 degrees +/- 4.0 degrees ) and the TS-EOP line (0.8 degrees +/- 3.2 degrees ) were significantly smaller than the angles between the ACPC line and the OML (-12.6 degrees +/- 4.2 degrees ; P < .05). In actual scanned images, the angle differences between the TS-OP (TS-IOP + TS-EOP) line and the ACPC line (0.3 degrees +/- 4.5 degrees ) were statistically smaller than the angles between the OML and the ACPC line (-6.6 degrees +/- 3.9 degrees ; P < .05). TS-OP lines are nearly parallel to the ACPC line.

Mean subaxial space available for the cord index as a novel method of measuring cervical spine geometry to predict the chronic stinger syndrome in American football players

The chronic stinger syndrome is a distinct entity from acute stingers and has been shown to have its own pathophysiology that, unlike acute stingers, may reflect long-standing geometrical changes of the subaxial spinal canal and chronic irritation/degeneration of the exiting nerve root complex. There is no method available, however, to accurately predict these symptoms in athletes. The mean subaxial cervical space available for the cord (MSCSAC) is a novel alternative to the Torg ratio for predicting neurological symptoms caused by cervical spondylosis in elite athletes. It is the goal of this study to determine critical values for this measurement index and to retrospectively correlate those values to neurological symptoms. Magnetic resonance images obtained in 103 male athletes participating in the 2005 and 2006 National Football League Scouting Combine and a control group of 42 age-matched male nonathletes were retrospectively reviewed. The Torg ratio and SAC values were calculated in triplicate at each cervical level from C3-6 by using lateral radiographs and midsagittal T2-weighted MR images of the cervical spine, respectively. These values were then averaged for each individual to produce mean subaxial cervical Torg ratio (MSCTR) and MSCSAC values. Receiver operating characteristic curves were constructed for each measurement technique and were compared based on their respective area under the curves (AUCs). The MSCSAC difference between athletes with and without chronic stingers was statistically significant (p < 0.01). The difference between athletes with and without chronic stingers compared with controls was also statistically significant (p < 0.001 and p < 0.001, respectively). The AUC for the MSCSAC was 0.813, which was significantly greater than the AUC for both the MSCTR (p = 0.0475) and the individual Torg ratio (p = 0.0277). The MSCTR had the second largest AUC (0.676) and the conventional method of measuring individual Torg ratio values produced the lowest AUC (0.661). It was found that using the MSCSAC with a critical value of 5.0 mm produced a sensitivity of 80% and a negative likelihood ratio of 0.23 for predicting chronic stingers. Lowering the cutoff value to 4.3 mm for the MSCSAC resulted in a possible confirmatory test with a specificity of 96% and a positive likelihood ratio of 13.25. A critical value of 5.0 mm for the MSCSAC provides the clinician with a screening test for chronic stingers and anything < 4.3 mm adds additional confidence as a confirmatory test. These results are approximately 20% more accurate than the classic Torg ratio based on our AUC analysis. It was found that measuring the spinal geometry throughout the length of the subaxial cervical spine produced a more reliable method by which to predict neurological symptoms than the traditional approach of measuring individual levels. This shows that the underlying pathogenesis of the chronic stinger syndrome is best characterized as a process that involves the entire subaxial region uniformly.