Computed Tomograpy Research Articles

Positron emission tomography guided dose painting by numbers of lung cancer: Alanine dosimetry in an anthropomorphic phantom.

Dose painting by numbers (DPBN) require a high degree of dose modulation to fulfill the image-based voxel wise dose prescription. The aim of this study was to assess the dosimetric accuracy of 18F-fluoro-2-deoxy-glucose positron emission tomography(18F-FDG-PET)-based DPBN in an anthropomorphic lung phantom using alanine dosimetry. A linear dose prescription based on 18F-FDG-PET image intensities within the gross tumor volume (GTV) of a lung cancer patient was employed. One DPBN scheme with low dose modulation (Scheme A; minimum/maximum fraction dose to the GTV 2.92/4.26Gy) and one with a high modulation (Scheme B; 2.81/4.52Gy) were generated. The plans were transferred to a computed tomograpy (CT) scan of a thorax phantom based on CT images of the patient. Using volumetric modulated arc therapy (VMAT), DPBN was delivered to the phantom with embedded alanine dosimeters. A plan was also delivered to an intentionally misaligned phantom. Absorbed doses at various points in the phantom were measured by alanine dosimetry. A pointwise comparison between GTV doses from prescription, treatment plan calculation and VMAT delivery showed high correspondence, with a mean and maximum dose difference of <0.1Gy and 0.3Gy, respectively. No difference was found in dosimetric accuracy between scheme A and B. The misalignment caused deviations up to 1Gy between prescription and delivery. DPBN can be delivered with high accuracy, showing that the treatment may be applied correctly from a dosimetric perspective. Still, misalignment may cause considerable dosimetric erros, indicating the need for patient immobilization and monitoring.

Efficacy of preoperative neutrophil-to-lymphocyte ratio in determining lymph node metastases in testicular cancer

Purpose: Testicular cancer is the most common solid tumor in young men between the ages of 20-35 and has excellent clinical outcomes with appropriate treatment. Neutrophil-to-lymphocyte-ratio (NLR) is related with prognosis and relapse in different solid tumors. We aimed to investigate the relation of presence and size of regional lymph node metastasis with NLR in testicular cancer. &#x0D; Materials and Methods: A total of 72 testicular cancer patients were included in the study. All medical records were retrospectively collected. NLR was calculated as the count of neutrophil divided by the count of lymphocyte. Chest and abdomen computed tomograpy (CT) scans of all patients were evaluated for metastases. &#x0D; Results: The mean age was 32.18±8.89 years. The pathologic classification was seminoma in 43% and nonseminoma in 57% of patients. Of 72 patients, 32 (44.4%) had lymph node positivity and 40 (55.6%) hadnot. The mean NLR value was 2.63±1.79 for all cohort. The mean NLR was significantly lower in patients with lymph node negative disease (for lymph node positive and negative disease 3.19±2.32 and 2.25±1.06, respectively.). In the ROC analysis, 2.5 was determined as the cut-off value for NLR to assess lymph node status. Conclusion NLR is a cheap and readily available index that can be used to determine lymph node metastases in testicular GCTs.

Hypervascular pancreatic metastasis: an easy imaging diagnostic?

Learning objectives. To review the computed tomograpy (CT) and magnetic resonance imaging (MRI) features of hypervascular pancreatic metastases (HPM). To discuss the main differential diagnosis of HPM. Materials and method. We retrospectively analyzed images from the CT and MRI evaluations of six patients who were diagnosed with HPM by morphopathological examination in the last ten years. Results. In our study, hypervascular pancreatic metastases corresponded to renal cell carcinoma, breast carcinoma and uterine leiomyosarcoma. In non-enhanced CT (NECT), all lesions were isodense or slightly hypodense. After i.v. injection of contrast medium (CM), hypervascular pancreatic metastases have displayed an early arterial phase enhancement, followed by rapid washout in the portal and delayed phases images. Contrast-enhanced CT showed for pancreatic metastases from uterine leio­myo­sarcoma a gradual enhancement. The common ap­pea­rance in MRI for HPM was hypointense in T1 weighted image (wi), heterogeneous aspect in T2 wi or mo­de­ra­tely hyperintense signal with restricted diffusion. After Gd-based CM i.v. injection, HPM showed the same dy­namic as in CT evaluation. Conclusions. HPM may create a diagnostic challenge, therefore the pathological exa­mi­na­tion remains essential and represents the gold standard for the final diagnosis.

Efficacy and safety of artificial pneumothorax with position adjustment for CT-guided percutaneous transthoracic microwave ablation of small subpleural lung tumors.

BackgroundTo evaluate the efficacy and safety of artificial pneumothorax with position adjustment for computed tomograpy (CT)‐guided percutaneous transthoracic microwave ablation (MWA) of small subpleural lung tumors.MethodsFifty‐six patients with small subpleural lung tumors (< 3.0 cm) entered the study and underwent CT‐guided MWA with (group I: 24 patients with 24 tumors) or without (group II: 32 patients with 34 tumors) the support of artificial pneumothorax. Follow‐up contrast‐enhanced CT scans were reviewed. Pain VAS (visual analog scale) scores at, during, and after ablation were compared between the two groups. Technical success, technique efficacy, local tumor control and complications were compared.ResultsCreation of the artificial pneumothorax was achieved for 24/24 (100%) in group I and no complication related to the procedure was observed. Technical success of MWA was achieved for all 58 tumors. Primary efficacy of MWA was achieved in 23 of 24 tumors (95.8%) treated in group I, and 32 of 34 tumors (94.1%) treated in group II (P = 0.771). The 12‐month local tumor control was achieved in 87.5% (21/24) in group I compared with 88.2% (30/34) in group II (P = 0.833). Pain VAS scores in group I were significantly decreased after the pneumothorax induction at, during, and after ablation compared with group II (P < 0.05). There was no significant difference in MWA‐related complications (P > 0.05).ConclusionArtificial pneumothorax with position adjustment for CT‐guided MWA is effective and may be safely applied to small subpleural lung tumors. Artificial pneumothorax is a reliable therapy for pain relief.

Future liver remnant hypertrophy with Yttrium90Radioembolization in a patient with gastric neuroendocrine tumour liver metastasis

Background: Here we report a case of extensive gastric neuroendocrine tumour liver metastasis where an adequate future liver remnant (FLR) could be achieved with multiple Yttrium 90 (Y 90) radioembolizations before definitive surgery. Methods: A 56 year-old male was admitted to our centre with a right lobe liver metastasis of gastric neuroendocrine tumor. A resection area of 1564 cm3 (85% total liver volume) with multiple lesions and only 276 cm3 (15%TLV) FLR were determined by computed-tomograpy (CT) before Y 90 radioembolization. Results: After 3 embolizations in a years span, control CT scans showed adequate FLR (42%TLV). Total gastrectomy and right trisectionectomy were performed at the same session. Patient did not have postoperative liver failure however he had a prolonged recovery period requiring respiratory failure. At postoperative 7th month, he is without tumor and has normal liver function tests. Conclusion: Preoperative Y 90 radioembolization may be an optional procedure to provide an adequate FLR in patients with extensive liver malignancies.

Computerized Tomographic Assessment of Vocal Cord Palsy: Otolaryngologist's Purview

ABSTRACT Aims and objectives Vocal cord palsy (VCP) can be definitely depicted on computed tomograpy (CT) scan by identifying key points at the level of true vocal cords and aryepiglottic folds. There are various VCP mimics and imaging shortcomings, and these can usually be circumvented by thoughtfully assessing the scan plan and level, and a diligent search for additional characteristics. Materials and methods This retrospective study consisted of 10 cases of unilateral VCP, who all had been clinically diagnosed of VCP and further evaluated by CT. Pre- and postcontrast enhanced axial CT from skull base to aorto-pulmonary window were done and multiplanar three-dimensional reconstruction of images in coronal and sagittal planes along with volume-rendered imaging was done. Results Most consistent findings in VCP were thickening of ipsilateral aryepiglottic fold and medialization of ipsilateral aryepiglottic fold (100%), followed by dilation of ipsilateral pyriform sinus (90%) and dilatation of ipsilateral laryngeal ventricle (80%). Etiologic causes were ascertained in three cases: Thyroid malignancy, tuberculosis, and pyriform sinus malignancy. The last etiology was probably a VCP mimic. Conclusion Radiologic evaluation is inarguably useful for determining the etiology of VCP, particularly for lesions within neck and thoracic cavity. Most crucial objective in assessing a case of VCP is to exclude the presence of a life-threatening primary lesion as the cause of VCP. How to cite this article Pandey AK, Gangrade S, Malhotra A, Varma A, Maithani T. Computerized Tomographic Assessment of Vocal Cord Palsy: Otolaryngologist's Purview. Int J Phonosurg Laryngol 2016;6(2):57-63.

Lingual-occlusal surface position predicts retroglossal obstruction in patients with obstructive sleep apnea hypopnea syndrome

Conclusion: Lingual-occlusal surface position was significantly related to retroglossal obstruction, and lingual-occlusal surface position may be an available reference in clinical practice for the preliminary assessment of retroglossal obstruction. Objective: To investigate the relationship between lingual-occlusal surface position and retroglossal obstruction in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Materials and methods: A total of 140 patients with OSAHS diagnosed by polysomnography (PSG) were enrolled. Lingual-occlusal surface position was evaluated and classified into three types. Airway computed tomograpy (CT) was performed to measure the retroglossal cross-sectional area and inner diameter. The PSG was repeated after the nasopharyngeal tube insertion (NPT-PSG). The NPT-PSG results, CT-measured data and incidence of retroglossal obstruction were compared among the different lingual-occlusal surface positions groups. Results: The demographics of OSAHS patients with different lingual-occlusal surface positions was similar. As lingual-occlusal surface position type varied from type I to type III, retroglossal cross-sectional area and inner diameter decreased, retroglossal airway obstruction rate increased, apnea hypopnea index (AHI) measured by NPT-PSG increased, and lowest oxygen saturation (LaSO2) decreased.

Comparison between Computed Tomography &amp; Fluoroscopy Guided Facet Joint Block in Lumbar Spine

Background Data: Facet joint disorders are main source of chronic low back pain with a prevalence of 16.7%. Facet joint block is performed for diagnostic or therapeutic purposes and generally is carried out under computed tomograpy(CT) or fluoroscopy. Facet joint block is the gold standard in diagnosis of facet joint syndrome. It can also relief pain for up to 6 months. Purpose: To identify which imaging modality (CT or fluoroscopy) is more suitable to guide the procedure of lumbar facet joint block, and results in better relieve of symptoms.Study Design: Prospective analytic clinical case study.Patients and Methods: Sixty eight lumbar facet joints representing 24 patients were injected in the radiology department, Suez Canal University Hospital, Ismailia, Egypt from 1/2005 to 12/2010. All cases were suspected of having facet jointdisorders based on clinical and radiological data. After clinical examination and reviewing lumbar images to identify target facets, every patient underwent facet joint block under either CT or fluoroscopy. Visual Analogue Scale was used to assessimprovement of symptoms. Results: Fluoroscopy was more successful in guiding the injections (success rate 77.7% compared with 31.25% in CT guidance). It is also faster (6:37 minutes per joint compared with 10:54 minutes for CT guidance). Less number of trials were required (1.7 trial compared with 6.6 trials with CT guidance). Fluoroscopy exposedthe patients and the radiologist to much irradiation (21.3 rad compared to 0.3 rad in CT guidance). Decreased bone density and laminectomy impair fluoroscopy guidance. CT guidance is difficult in patient with marked arthropathy and coronally oriented joints (8 trials compared with 5.6 for normally appearing joints). Both groups showed significant improvement of symptoms. Conclusion: Fluoroscopy should be the primary choice for guiding lumbar facet jointblock. It is more successful and faster. Its disadvantages include much irradiation to patients and radiologists, and difficulty in patients with laminectomy and decreased bone density. CT can then be used to guide the block. Both techniques are effective in pain reduction. (2012ESJ035)

Obturator Hernia in an Elderly Woman Presenting with Aspiration Pneumonia and Respiratory Failure

Obturator hernia is a rare but important cause of intestinal obstruction. The mortality rate is high if the diagnosis is not made early and surgical intervention is delayed. We report an 88-year-old female patient who presented with aspiration pneumonia and respiratory failure. She did not have nausea/vomiting and physical examination was unremarkable. She was fed through a nasogastric tube, but no gastric emptying was noted. An abdominal/pelvic computed tomograpy (CT) scan performed 5 days after the presentation revealed a left incarcerated obturator hernia. Emergency laparotomy was performed and the patient eventually recovered. This case reminds us that aspiration pneumonia may be the presenting feature of obturator hernia and a clue to its early diagnosis.

CT Imaging Findings of Ruptured Ovarian Endometriotic Cysts: Emphasis on the Differential Diagnosis with Ruptured Ovarian Functional Cysts

ObjectiveThe purpose of this study is to assess the prevalence of abnormal CT findings in patients with surgically proven ruptured endometriotic cysts, as compared with those abnormal CT findings of ruptured ovarian functional cysts.Materials and MethodsThis study included 13 retrospectively identified patients with surgically confirmed ruptured ovarian endometriotic cysts and who had also undergone preoperative CT scanning during the previous seven years. As a comparative group, 25 cases of surgically confirmed ruptured ovarian functional cysts were included. We assessed the morphologic features of the cysts and the ancillary findings based on CT.ResultsFor the endometriotic cysts, the mean maximum cyst diameter was significantly larger than that of the functional cysts (70.1 mm versus 36.4 mm, respectively, p < 0.05). The endometriotic cysts frequently had a multilocular shape and a thicker cyst wall, as compared to that of functional cysts, and these differences were statistically significant. Among the ancillary findings, endometriotic cysts showed a significantly higher prevalence of loculated ascites, ascites confined to the pelvic cavity without extension to the upper abdomen, and peritoneal strandings and infiltrations (p < 0.05). Although 11 of the 25 cases of functional cysts showed active extravasation of contrast material at the ovarian bleeding site, only one of 13 cases of endometriotic cysts showed active extravasation.ConclusionThe diagnosis of ruptured endometriotic cyst should be suspected for a woman in whom CT reveals the presence of multilocular or bilateral ovarian cysts with a thick wall and loculated ascites confined to the pelvic cavity with pelvic fat infiltrations.

The Black Sombrero: A Helpful Landmark in Axial Imaging Evaluation of the Larynx and Hypopharynx

Computed Tomograpy (CT) scan and Magnetic Resonance Imaging (MRI) evaluation of the larynx and hypopharynx can be tricky for the untrained eye. We discuss a peculiar pattern of the supraglottic airway at the level of the base of the epiglottis seen on axial CT and MR images, resembling a “black hat” or a “black sombrero.” The level of the base of the epiglottis also corresponds to that of the hyoid bone, where two valuable hypopharyngeal sub-sites are visible- the pyriform sinuses and the posterior hypophayngeal wall.&#x0D; &#x0D; A hat has basically two parts, an apical convex crown and a basal horizontal brim. (Figure 1.A) Correlating the hat’s appearance on axial CT and MR imaging, the hat appears black due to the presence of air at the supraglottic level wherein the crown is positioned anteriorly and the brim positioned posteriorly. (Figure 1.B)&#x0D; &#x0D; The top-most convex part of the crown corresponds to the base of the epiglottis. Anterior to it is the pre-epiglottic fat plane and the body of the hyoid bone. The crown is also flanked by the paraglottic fat plane on both sides that appears hypodense (dark) on CT and hyperintense (bright) on T1 MRI. On the other hand, the posterior-most portion of the hat’s brim abuts the posterior hypopharyngeal wall - laterally outlining the pyriform sinuses on each side. The area where the crown joins the brim corresponds to the aryepiglotic folds that are delineated laterally by the medial walls of the pyriform sinuses while its medial aspects correspond to portions of the supraglottis. (Figure 2)&#x0D; The size and configuration of the hat varies and can range from one with a big crown and a small brim (resembling a “bowler” or “derby hat”) to one with a tall crown and a floppy brim (resembling a “Mexican sombrero”). (Figures 2, 3) Infiltrating tumors and inflammatory processes can distort the hat’s usual symmetric configuration, and can be useful in determining possible sites of inflammation or infection, tumor origin, and spread to hypopharyngeal and supraglottic structures, as the hat’s center represents a potential space at the supraglottic area devoid of any soft tissue structures. (Figure 4)&#x0D; In radiology, “the bowler hat sign” and “Mexican hat sign” have been used to describe gastrointestinal polyps.1,2,3 The former “is produced by the acute angle of attachment of the polyp to the mucosa” while the latter “consists of two concentric rings and is produced by visualizing a pedunculated polyp head-on.”1 The “Mexican hat sign” has also been used to describe osmotic demyelination on MRI.4&#x0D; &#x0D; To our knowledge, these terms have not been applied to the interpretation of supraglottic and hypopharyngeal CT and MRI axial images. Recognition of the “Black Sombrero” pattern can be helpful in understanding the anatomic relationship of the supraglottic and hypopharynx structures on axial CT and MR imaging, particularly in the evaluation of supraglottic and hypopharyngeal tumor spread.

2D 의료영상의 3차원 입체영상 생성

Recently, diverse 3D image processing technologies have been applied in industries. Among them, stereoscopic conversion is a technology to generate a stereoscopic image from a conventional 2D image. The technology can be applied to movie and broadcasting contents and the viewer can watch 3D stereoscopic contents. Further the stereoscopic conversion is required to be applied to other fields. Following such trend, the aim of this paper is to apply the stereoscopic conversion to medical fields. The medical images can deliver more detailed 3D information with a stereoscopic image compared with a 2D plane image. This paper presents a novel methodology for converting a 2D medical image into a 3D stereoscopic image. For this, mean shift segmentation, edge detection, intensity analysis, etc are utilized to generate a final depth map. From an image and the depth map, left and right images are constructed. In the experiment, the proposed method is performed on a medical image such as CT (Computed Tomograpy). The stereoscopic image displayed on a 3D monitor shows a satisfactory performance.

The Black Sombrero: A Helpful Landmark in Axial Imaging Evaluation of the Larynx and Hypopharynx

Computed Tomograpy (CT) scan and Magnetic Resonance Imaging (MRI) evaluation of the larynx and hypopharynx can be tricky for the untrained eye. We discuss a peculiar pattern of the supraglottic airway at the level of the base of the epiglottis seen on axial CT and MR images, resembling a “black hat” or a “black sombrero.” The level of the base of the epiglottis also corresponds to that of the hyoid bone, where two valuable hypopharyngeal sub-sites are visible- the pyriform sinuses and the posterior hypophayngeal wall. &nbsp; A hat has basically two parts, an apical convex crown and a basal horizontal brim. (Figure 1.A) Correlating the hat’s appearance on axial CT and MR imaging, the hat appears black due to the presence of air at the supraglottic level wherein the crown is positioned anteriorly and the brim positioned posteriorly. (Figure 1.B) &nbsp; The top-most convex part of the crown corresponds to the base of the epiglottis. &nbsp;Anterior to it is the pre-epiglottic fat plane and the body of the hyoid bone. The crown is also flanked by the paraglottic fat plane on both sides that appears hypodense (dark) on CT and hyperintense (bright) on T1 MRI. On the other hand, the posterior-most portion of the hat’s brim abuts the posterior hypopharyngeal wall - laterally outlining the pyriform sinuses on each side. The area where the crown joins the brim corresponds to the aryepiglotic folds that are delineated laterally by the medial walls of the pyriform sinuses while its medial aspects correspond to portions of the supraglottis. (Figure 2) The size and configuration of the hat varies and can range from one with a big crown and a small brim (resembling a &nbsp;“bowler” or “derby hat”) to one with a tall crown and a floppy brim (resembling a “Mexican sombrero”). (Figures 2, 3) Infiltrating tumors and inflammatory processes can distort the hat’s usual symmetric configuration, and can be useful in determining possible sites of inflammation or infection, tumor origin, and spread to hypopharyngeal and supraglottic structures, as the hat’s center represents a potential space at the supraglottic area devoid of any soft tissue structures. (Figure 4) In radiology, “the bowler hat sign” and “Mexican hat sign” have been used to describe gastrointestinal polyps.1,2,3 The former “is produced by the acute angle of attachment of the polyp to the mucosa” while the latter “consists of two concentric rings and is produced by visualizing a pedunculated polyp head-on.”1 The “Mexican hat sign” has also been used to describe osmotic demyelination on MRI.4 &nbsp; To our knowledge, these terms have not been applied to the interpretation of&nbsp; supraglottic and hypopharyngeal CT and MRI axial images. Recognition of the “Black Sombrero” pattern can be helpful in understanding the anatomic relationship of the supraglottic and hypopharynx structures on axial CT and MR imaging, particularly in the evaluation of supraglottic and hypopharyngeal tumor spread.

Paraplegia after spontaneous dissection of the abdominal aorta

We report a case with spinal cord ischemia and consecutive paraplegia following spontaneous isolated abdominal aortic dissection (IAAD). A 63-year-old female was admitted to the surgical emergency room with severe lumbar back pain and accompanying paresthesia of both legs. Contrast enhanced computed tomograpy (CT) of the abdomen showed an infrarenal IAAD in a normal size aorta with patent lumbar arteries. It was assumed that a surgical or interventional approach would not be helpful to improve spinal cord perfusion. Therefore, non operative therapy consisted of lowering blood pressure to prevent further dissection. The patient developed an anterior spinal artery syndrome with permanent paraplegia. Thus, blood pressure was raised for optimal spinal cord perfusion. To lower the spinal pressure, cerebrospinal fluid drainage was attempted. A three month follow-up CT scan showed spontaneous remodelling of the aorta. The neurological deficit persisted. IAAD is a rare differential diagnosis of lumbar back pain and can be associated with paraplegia as the leading symptom. Individualized treatment is indicated. Surgical treatment options concerning paraplegia are limited.

Implementation of helical computed tomography in magnetic resonance imaging.

To provide a rapid sequence for volumetric imaging of large fields of view. The volumetric imaging principles of x-ray helical computed tomograpy (CT) were implemented here on an MRI scanner. However, using the advantages offered by MRI, spiral trajectories in K-space were incorporated to make the helical scan more efficient. Thus, data acquisition and interpolations were conducted in K-space and images reconstructed by gridding and applying the inverse Fourier transform. The rapid spiral helical (RASH) imaging method was evaluated by computer simulations, by scanning phantoms and an in vitro heart, and by comparison to conventional multislice interleaved spirals (MSIS) imaging. A significant time saving (61.4% to 85.9%) relative to MSIS was achieved without significant degradation in image quality. Volume assessment and in-plane resolution by RASH were almost identical to the MSIS pulse sequence. The corresponding increase in effective slice width was estimated to range (for the values studied here) from 1.31 to 2.5 according to the selection of the helical pitch and the slice thickness used for imaging. The suggested method offers the advantages provided by x-ray helical CT and can be useful in MRI volumetric scanning of large objects.

Donor and recipient outcomes in right lobe adult living donor liver transplantation.

Severe donor organ shortage has provided the impetus for adult living donor liver transplantation (ALDLT). Despite rapid implementation and expansion of the procedure, outcome analysis of ALDLT is still incomplete. This study analyzed both donor and recipient outcomes after ALDLT at a single center. ALDLT performed at UCLA between August 1999 and November 2001 were reviewed retrospectively. Twenty recipients (14 men and 6 women) with a mean age of 48.8 +/- 9.7 (29 to 66) years underwent right lobe ALDLT. By computed tomograpy (CT), graft/recipient weight ratio (GRWR) was 1.3 +/- 0.3 (1 to 2.2). Overall 1-year patient and graft survival rates were 95% and 85%, respectively. One recipient died of heart failure with normal liver function 5 months after transplantation. Three grafts (14%) were lost and all three patients underwent successful cadaveric retransplantation. Complications were classified according to the Clavien grading system with all but 3 recipients encountering at least one complication. Nine (45%) had grade 1 (minor), 10 (50%) had grade 2 (potentially life threatening without residual disease/disability), 3 (14%) had grade 4A (retransplantation) and one grade 4B (death). Right lobectomy for living donation was performed in 20 patients (12 men, 8 women). Residual left lobe volumes were 36 +/- 5.3 (23.9 to 47.9)% of total donor liver volume. No donor required intensive care unit admission and median hospital stay was 7.5 (6 to 14) days. One donor was aborted after intraoperative biopsy showed > 50% macrovesicular steatosis. No donor mortality or long-term complications were encountered. Five grade 1 minor complications, by Clavien Classification, occurred in 4 of 20 (20%) donors. ALDLT using right lobe grafts is an effective procedure to expand a severely depleted donor, but is associated with a high complication rate despite good survival outcomes. Continuous standardized reporting of ALDLT outcomes is required to allow successful and safe implementation of the procedure.

Thursday, October 31, 2002 3:16–3:46 pm Select Poster Presentations: Preoperative and postoperative computer tomography evaluation of structures at risk with anterior spinal fusion

Purpose of study: With the increasing popularity of anterior spinal fusion (ASF) for AIS, there has also been an increasing concern over the proximity of the thoracic aorta (TA) to the screw tips and the possibility of vessel was erosion over time. This preoperative and postoperative computed tomograpy (CT) study attempts to define the relative position of the TA, and other vital structures in deformity patients, to the spine (preoperatively), as well as to the projected instrumentation (postoperatively) by level and curve magnitude.Methods used: Twenty consecutive patients (17 female, 3 male) with an average age of 14.5 years (range, 12.4 to 15.5 years) with AIS and a right main thoracic/Lenke 1 curve, average 55.2 degrees (range, 50 to 66 degrees; average apex T8), underwent preoperative and postoperative CT scans as part of their planned ASF. All images were analyzed for proximity (distance from the mid-vertebral body) and position to (as defined relative to the center of the vertebral body in the axial plane) the spine preoperatively and the projecting screw tip postoperatively. These were compared with 10 age-matched nondeformity thoracic CT scans to assess the relative position of the thoracic aorta to the vertebral bodies by level. Preoperative and postoperative plain radiographs were also analyzed for curve magnitude, correction and fusion levels to assess the possible effect of these variables on thoracic aorta proximity.of findings: Postoperative curve magnitude averaged 26.9 degrees (range, 17 to 40 degrees; 51% correction) with an average follow-up of 4.1 years (range, 3.2 to 7.0 years) analyzing 151 screws (7.5 levels/patient). The trachea/main bronchi, esophagus and pleura were not found to be at risk. Screw to spinal canal distance averaged 5.3 mm (range, 3.5 to 8.2 mm), and +4.5 degrees (range, −11 to +15 degrees) from the coronal axis. Screw tip extrusion (distance beyond far cortex) averaged 2.8 mm (0 to 5 mm). Spine/screw tip to aorta distances are shown in Table 1Table 1Control⩽55 preop⩽55 postop⩾55 preop⩾55 postopProximal (n=20)5.9 mm5.1 mm3.6 mm4.1 mm3.5 mmPeriapical (n=40)5.1 mm4.8 mm2.0 mm15.2 mm1.6 mm1Distal (n=51)3.8 mm5.0 mm2.4 mm13.8 mm2.2 mm11denotes p < 0.05.Additionally, 23 of 151 screws (15%) were thought to be adjacent to the TA with 4 of 60 proximal screws (7%) judged to be juxtaposed to the aorta, whereas 6 of 40 periapical screws (15%) and 13 of 51 distal screws (26%) were juxtaposed (p<.05). There were no screws compressing (indenting) the aorta and no complications.Relationship between findings and existing knowledge: The course of the thoracic aorta may vary in individuals and in deformity. However, it generally moves from a relatively anterolateral position proximally, to posteromedial position at the apex, and then to a more anterior position distally. Consequently, the aorta moves closer to the screw tips both at the apex and distally, whereas the distal screws are more frequently juxtaposed to the descending aorta.Overall significance of findings: Because of the course of the thoracic aorta and the tethering effect of the diaphragm hiatus, the distal screws are frequently juxtaposed to the descending aorta in anterior spinal fusion.Disclosures: No disclosures.Conflict of interest: Lawrence Lenke, grant research support; consultant; and other support.

Incorporating functiona imaging, information into radiation treatment

Three-dimensional treatment planning systems allow the clinician to define tumor and normal anatomy of computed tomograpy (CT) scans and project the result onto a digitally reconstructed radiograph (DRR) for comparison with a simulation or portal film. Unfortunately, the CT scan does not always show the tumor accurately. First, the tumor may have either been removed surgically, or cytoreduced with chemotherapy before the treatment planning scan was taken. Or, the planning CT may not be the ideal imaging modality for a particular tumor, magnetic resonance imaging (MRI) or positron-emission tomography (PET) being much better. In either case, the nonplanning images provide more reliable data as to the position and extent of tumor than do the CT. A 3D/3D registration between the diagnostic and planning image must then be performed to make the data from both images available for the planning process. Methods of performing accurate 3D/3D registration of dissimilar images have been studied extensively by experts in image processing, but the techniques have not yet been fully adopted by the medical community. In addition, there is no standard way of dealing with the multiple tumor volumes that will be generated by full multimodality treatment planning. This article ends with speculation as to the extent to which multimodality image-based treatment planning can improve cancer treatment rates. New imaging modalities such as magnetic resonance spectroscopy, PET, or functional imaging, tuned to the particular tumor type, might reveal more than just the gross tumor volume seen on CT or MRI. One could imagine radiation treatment to many sites in the body under image guidance that would result in cure of metastatic disease, should the cancer be confined to a reasonable number of discrete sites.

The clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian multicentre study

Purpose: This study of patients with minor head injury was designed to investigate the relation of S-100 protein measurements to computed tomograpy (CT) findings and patients outcomes. Increased serum levels of this protein were hypothetized to predict intracranial pathology and increased frequency of post-concussion symptoms. Methods: One hundred and eighty-two patients were studied with Glasgow Coma Scale scores of 13-15. The study recruited patients from three Scandinavian neurotrauma centres. Serum levels of S-100 protein were measured at admittance and CT scans of the brain were obtained within 24 hours postinjury in all patients. Outcome was evaluated with the Rivermead Postconcussion Symptoms Questionnaire (RPQ) 3 months after the injury. Results: Increased serum level of S-100 protein was detected in 69 (38%) patients, and CT scan demonstrated intracranial pathology in 10 (5%) (brain contusion in seven, epidural haematoma in two, traumatic subarachnoid haemorrhage in one). The proportion of patients with detectable serum level was significantly (p < 0.01) higher among those with intracranial pathology (90%) compared to those without (35%). The negative predictive value of an undetectable S-100 level was 0.99. Sixty-two per cent reported one or more post-concussion symptoms at follow-up. A trend was observed towards an increased frequency of post-concussion symptoms among patients with detectable serum levels. Conclusions: Undetectable serum level of S-100 protein predicts normal intracranial findings on CT scan. Determination of S-100 protein in serum may be used to select patients for CT scanning. Increased S-100 serum levels may be more related to post-concussion symptoms caused by mild traumatic brain injury than to symptoms of psychological origin.

MR-Evaluation of Acute Cervical Spine Trauma: The Significance of Discoligamental Injury

Following acute and severe trauma of the cervical spine 28 patients underwent magnetic resonance imaging (MRI). Fracture or dislocation had been diagnosed by computed tomograpy (CT) or plain films in 16 patients whereas in 12 patients no bone injury had been detected. MRI revealed discoligamental injury in 12/16 patients with fracture and in 7/12 of the patients without fracture. MRI was considered to be necessary in 6/12 patients who underwent surgery in the first group and in 5/7 patients with surgery of the second group.