Accurate and efficient separation of left and right lungs from 3D CT scans: A generic hysteresis approach

Background: Many infants with congenital muscular torticollis (CMT) have deformational plagiocephaly (DP), and a small cohort also demonstrate mandibular asymmetry (MA). The aim of this retrospective study was to evaluate mandibular changes in these infants with previous computed tomography (CT) scans who underwent physical therapy (PT) to treat CMT. Methods: A retrospective study included patients presenting to a pediatric plastic surgery clinic from December 2010 to June 2012 with CMT, DP, and MA. A small subset of these patients initially received a 3D CT scan due to concern for craniosynostosis. An even smaller subset of these patients subsequently received a second 3D CT scan to evaluate for late-onset craniosynostosis. Patients were treated with PT for at least 4 months for CMT. Initial CT scans were retrospectively compared to subsequent CT scans to determine ramal height asymmetry changes. Clinical documentation was reviewed for evidence of MA changes, CMT improvement, and duration of PT. Results: Ten patients met inclusion criteria. Ramal height ratio (affected/unaffected) on initial CT was 0.87, which significantly improved on subsequent CT to 0.93 ( P < .05). None of the patients were diagnosed with craniosynostosis on initial CT. One patient was diagnosed with late-onset coronal craniosynostosis on subsequent CT. Conclusions: We identified a small cohort of infants with MA, CMT, and DP. These patients uniformly demonstrated decreased ramal height ipsilateral to the affected sternocleidomastoid muscle. Ramal asymmetry measured by ramal height ratios improved in all infants undergoing PT.

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Automated 3D MRI Allows for Accurate Evaluation of Glenoid Bone Loss as Compared to 3D CT

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118s00089 ◽

2018 ◽

Vol 6 (7_suppl4) ◽

pp. 2325967118S0008

Author(s):

Drew A. Lansdown ◽

Robert Dawe ◽

Gregory L. Cvetanovich ◽

Nikhil N. Verma ◽

Brian J. Cole ◽

...

Keyword(s):

Bone Loss ◽

3D Reconstruction ◽

Ct Scan ◽

Glenoid Bone Loss ◽

Ct Scans ◽

Reconstruction Method ◽

Slice Thickness ◽

3D Ct ◽

Ct Reconstruction ◽

3D Mri

Objectives: Glenoid bone loss is frequently present in the setting of recurrent shoulder instability. The magnitude of bone loss is an important determinant of the optimal surgical treatment. The current gold-standard for measurement of glenoid bone loss is three-dimensional (3D) reconstruction of a computed tomography (CT) scan. CT scans, however, carry an inherent risk of radiation and increased cost for a second modality. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast and may allow resolution of bony structures to generate 3D reconstructions without a risk of ionizing radiation. We hypothesized that automated 3D MRI reconstruction would offer similar measurements of glenoid bone loss as recorded from a 3D CT scan in a clinical setting. Methods: A retrospective review was performed for fourteen patients who had both pre-operative MRI scan and CT scan of the shoulder. All MR scans were performed on a 1.5 T scanner (Siemens) utilizing a Dixon chemical shift separation sequence and the out-of-phase images with 0.90 mm slice thickness. Reconstructions of the glenoid were performed from axial images (Figure 1A) using an open-platform image processing system (3D Slicer; slicer.org). A single point on the glenoid was selected and a standard threshold was used to build a 3D model (Figure 1B). High-resolution CT scans underwent 3D reconstruction in Slicer based on Houndsfield Unit thresholding. Glenoid bone loss on both scans was measured with the Pico method by defining a circle of best fit using the inferior 2/3 of the glenoid and determining the percent area missing from this circle. Pearson’s correlation coefficient was utilized to determine the similarity between MR and CT based measurements. Statistical significance was defined as p<0.05. Results: The correlation between 3D MR and CT-based measurements of glenoid bone loss was excellent (r = 0.95, p<0.0001). The mean bone loss as measured by the 3D MR was 13.2 +- 7.2% and was 12.5 +- 8.6% for the 3D CT reconstruction (p=0.32). Bone loss in this cohort ranged from 3.7-25.4% on 3D MR and 1.4-26.0% on 3D CT. The root-mean-square difference between measurements was 2.7%. Conclusion: There was excellent agreement between automated 3D MR and 3D CT measurements of glenoid bone loss and minimal differences between these measurements. This reconstruction method requires minimal post-processing, no manual segmentation, and is obtained with widely-available MR sequences. This method has the potential to decrease the utilization for CT scans in determining glenoid bone loss. [Figure: see text]

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The Feasibility Study of C1 Posterior Arch Crossing Screw Fixation in Adult Thai Population: A Computed Tomographic Morphometric Analysis Study

Journal of the Medical Association of Thailand ◽

10.35755/jmedassocthai.2021.03.11945 ◽

2021 ◽

Vol 104 (3) ◽

pp. 475-481

Keyword(s):

Computed Tomography ◽

Vertebral Artery ◽

Screw Fixation ◽

Ct Scans ◽

Vertebral Artery Injury ◽

Posterior Arch ◽

Thai Population ◽

Artery Injury ◽

Left And Right ◽

The Mean

Objective: Atlantoaxial instability can be caused by various etiologies and surgical fixation is often required. Various methods have been described for atlantoaxial fixation. Screw fixation is associated with an increased risk of vertebral artery injury especially in patients with an anomalous vertebral artery location or abnormal bony anomalies. A new C1 posterior arch crossing screw fixation technique was proposed to reduce the risk of vertebral artery injury. The present study aimed to assess morphometric CT analysis of atlas for C1 posterior arch crossing screw fixation in Thai people. Materials and Methods: The present research was an observational study that reviewed 150 computed tomography (CT) scans of the patients who had neck trauma or any other complaint requiring craniocervical investigations. Atlantoaxial articulation deformities due to trauma, infections, neoplasm, congenital anomaly, inflammatory disease, incomplete CT scan analysis, and history of surgical intervention of the cervical spine were excluded. All the images were measured for the height of the posterior tubercle, the width of the posterior arch was measured bilaterally in three parts on the axial plane, part 1: medial of the VA groove, where the arch transforms into the VA groove, part 2: the middle part between the posterior tubercle and medial of the VA, and part 3: posterior tubercle, length of the screw, and the screw projection angle was calculated. Results: Out of the 139 CT scans analyzed, the mean measurement of posterior arch height was 7.45±1.03 mm, wherein 73.3% exceed 7 mm. The mean width of the left posterior arch in part 1, 2, and 3 was 4.50±0.70 mm, 4.90±0.70 mm, and 5.70±0.80 mm, respectively, and the width of the right posterior arch in part 1, 2, and 3 was 4.50±0.70 mm, 4.80±0.70 mm, and 5.60±0.80 mm, respectively. The mean crossing screw length of the Left and Right was 17.02±3.04 mm and 17.37±2.75 mm, respectively. The mean angle of screw of the Left and Right was 24.62±3.38 degrees and 24.78±3.57 degrees, respectively. There were no significant differences in these variables between gender or sides (p>0.05) except the mean angle of the screw between gender (p<0.05). Conclusion: C1 posterior arch screw fixation is feasible in the adult Thai population. Preoperative thin-cut CT is essential for planning successful posterior arch crossing screws placement. Keywords: C1 posterior arch, Computed tomography, Crossing screw fixation

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Planning Mandibular Distraction: Preliminary Report

The Cleft Palate-Craniofacial Journal ◽

10.1597/1545-1569_1995_032_0071_pmdpr_2.3.co_2 ◽

1995 ◽

Vol 32 (1) ◽

pp. 71-76 ◽

Cited By ~ 8

Author(s):

H. Wolfgang Losken ◽

Gary T. Patterson ◽

Spiros A. Lazarou ◽

Timothy Whitney

Keyword(s):

Computed Tomography ◽

Preliminary Report ◽

Three Dimensional ◽

Ct Scans ◽

Obtuse Angle ◽

3D Ct ◽

Mandibular Angle ◽

Mandibular Distraction ◽

Different Ages ◽

Horizontal Ramus

Normal lengths of the vertical ramus, body, and angle of the mandible at different ages are presented. Before mandibular distraction is embarked on, the extent of the deficiency of the mandible is assessed. The length of the vertical ramus and body are measured on cephalometric radiographs or three-dimensional computed tomography (3D CT) scans. Deficiency of the length of the mandible is calculated. The position of the pin placement angle (from the horizontal ramus) is calculated by means of the following formula: 180 degrees minus mandibular angle times vertical ramus deficiency divided by total deficiency. Placing the pins correctly will result in correction of the vertical ramus and body deficiency of the mandible and the excessively obtuse angle of the mandible will become more acute.

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An Aberrant Line on CT Head: The Mendosal Suture

Journal of Neurosciences in Rural Practice ◽

10.1055/s-0040-1713304 ◽

2020 ◽

Vol 11 (03) ◽

pp. 502-503

Author(s):

Jigish Ruparelia ◽

Rajnish Patidar ◽

Jaskaran Singh Gosal ◽

Mayank Garg ◽

Suryanarayanan Bhaskar ◽

...

Keyword(s):

Clinical Practice ◽

Volume Rendering ◽

Correct Diagnosis ◽

Anatomical Variations ◽

Ct Scans ◽

Clinical Implications ◽

3D Ct ◽

Radiological Findings ◽

Ct Head ◽

Variant Anatomy

AbstractA knowledge of variant anatomy is important in clinical practice. The skull bones have several normal anatomical variations, especially in the occipital bone. Accessory sutures have been described in newborns and young children.In this study, we discussed radiological findings of an accessory occipital suture in a 14-year-old child who had presented with mastoiditis and brain abscess. We further describe this “mendosal suture,” and its pathophysiology and clinical implications. It is important to bear this entity in mind to avoid misdiagnosing this as a fracture. The use of CT scans and 3D CT using volume rendering technique (VRT) helps in detection and correct diagnosis.

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