Prospective comparison of axial computed tomography and standard and panoramic radiographs in the diagnosis of mandibular fractures

Objective data comparing sensitivity and accuracy between traditional and computed imaging techniques used for diagnosing mandibular fractures is sparse. To address the paucity of information the authors studied prospectively 33 mandibular fractures in 21 consecutive patients with standard mandibular series, panoramic tomography, axial computed tomography (CT), and coronal CT. Differences in diagnostic accuracy and sensitivity as compiled by four blinded reviewers were calculated. Although overall sensitivities of mandibular fracture detection were not statistically significant between the imaging studies, a distinction between the four methods did exist. Coronal CT was the most accurate imaging method, followed by mandibular series, panoramic topography, and axial CT. Excluding technically inadequate studies, panoramic tomography was 100% accurate and sensitive. Diagnostic accuracy and sensitivity did not correlate measurably with reviewers' impressions of the quality of a particular exam. Axial CT detected significantly fewer angle fractures than standard radiographs (60% vs. 98%, p = 0.006) and coronal CT (60% vs. 100%, p = 0.008). False-positives were unusual except for plain mandibular radiographs. The clear definition of both coronal and axial CT scans made their analysis simpler than the plain radiographs. Lack of fracture displacement was the single most important factor in missed fractures with all modalities. Despite reviewer concerns about the quality of the plain mandibular series, the high accuracy and sensitivity of this imaging technique and applicability in all patients, coupled with its low cost, make it an excellent screening exam for all patients with suspected mandibular fractures. In clinically stable and cooperative patients with mandibular trauma, panoramic radiography and coronal CT are recommended to confirm clinical suspicions when the mandibular series is equivocal. To supplement the mandibular series in the uncooperative or multisystem trauma patient, axial CT scans have not been beneficial. These diagnostic modalities do not obviate the need for a careful physical exam.     

Spontaneous cerebrospinal fluid leakage detected by magnetic resonance cisternography--case report.

A 49-year-old male with no history of head trauma suffered cerebrospinal fluid (CSF) discharge from the left nostril for one month. Coronal computed tomography (CT) showed lateral extension of the sphenoid sinus on both sides and CSF collection on the left side. CT cisternography could not identify the site of CSF leakage. Heavily T2-weighted magnetic resonance (MR) imaging (MR cisternography) in the coronal plane clearly delineated a fistulous tract through the sphenoid bone into the sphenoid sinus. Patch graft with muscle fragment completely relieved the CSF rhinorrhea. Postoperative three-dimensional CT showed the two bone defects identified during surgery. Small bony dehiscences in the sphenoid bone and lateral extension of the sphenoid sinus predisposed the present patient to CSF fistula formation. MR cisternography in the coronal and sagittal planes is superior to CT scanning or CT cisternography for detection of the site of active CSF leakage.     

Measurement of vertebral rotation in standing versus supine position in adolescent idiopathic scoliosis

Thirty-three structural curves of 25 patients with adolescent idiopathic scoliosis were evaluated using computed tomography (CT) scans and plain radiography. The average Cobb angle on standing radiographs was 55.72 degrees and was observed to be corrected spontaneously to 39.42 degrees while the patients were in supine position (29.78% correction). Average apical rotation according to Perdriolle was 22.75 degrees on standing radiographs and 16.78 degrees on supine scanograms. The average rotation according to Aaro and Dahlborn on CT scans was 16.48 degrees. Radiographic measurements were significantly different from axial CT slice or scanogram measurements (p = 0.000), but the two latter measurements, both obtained in the supine position, did not appear to be different (p = 0.495). Deformities on the transverse plane as well as on the coronal plane are influenced by patient positioning. If the patient lies supine, the scoliosis curve corrects spontaneously to some degree on both planes. Measurements obtained from the scanograms by the Perdriolle method in the supine position are very similar to those obtained by CT. Perdriolle's is a simple, convenient, and reliable method to measure rotation on standing radiograms.     

Thermogangliolysis of the Gasserian ganglion under computed tomography fluoroscopy

Gasserian ganglion block is an established treatment for trigeminal neuralgia. A landmark approach assisted by X-ray fluoroscopy is the most common method; however, visualization of the foramen ovale is difficult in some cases. Here we report two cases in which a novel technique using modern computed tomography (CT) fluoroscopy was employed. A 63-year-old woman suffering pain in the maxillary nerve area was treated by thermogangliolysis under CT fluoroscopy. The patient was positioned on a CT stage with the head in an overhanging position. The CT gantry was set at an oblique angle to obtain a coronal view of the foramen ovale. The safest and shortest route to the foramen was designed using the CT image and a 22-gauge insulated needle was advanced following the designed route under CT fluoroscopy. The effect of the nerve block was estimated by injection of a test dose of mepivacaine, after which the ganglion was thermally coagulated at 90°C. Satisfactory analgesia was obtained in this case without any complications. Another patient (65 years old) was also treated by the same technique, and satisfactory pain relief was obtained. In conclusion, CT fluoroscopy-guided Gasserian ganglion thermolysis is considered a safe, quick, and effective treatment for trigeminal neuralgia.     

Fracture morphology of AO/OTA 31-A trochanteric fractures: A 3D CT study with an emphasis on coronal fragments

AimsThis study was designed to assess the incidence and morphology of coronal plane fragments in AO/OTA 31-A trochanteric fractures.Patients and methods156 cases of AO/OTA 31-A trochanteric fractures were retrospectively evaluated. Lateral radiographs were analyzed for the presence of coronal plane fragments followed by analysis of 3D CT reconstructions in these fractures. The incidence of coronal fragments identified on the lateral radiograph and 3D CT reconstructions were both calculated. Coronal fragment morphology was described based upon the origin and exit points of fracture lines and the number of fragments.Results and conclusionOn plain radiographs, a coronal plane fracture was identified in 59 cases, an incidence of 37.8% (59/156). In comparison, 3D CT reconstructions identified coronal plane fractures in 138 cases for an incidence of 88.4% (138/156). 3D CT reconstructions identified coronal fracture fragments in 81.9% (50/61) of AO/OTA 31-A1 cases, 94.5% (69/73) of 31-A2 cases, and 86.3% (19/22) of 31-A3 cases. Incidence of coronal fractures identified on plain radiographs of 3 AO/OTA 31-A1,A2,A3 groups was lower when compared to the incidence of coronal fractures identified on 3D CT. Of the 138 cases that had coronal plane fracture, 82 cases (59.4%) had a single coronal fragment (GT fragment 35 cases, GLT fragment 19 cases, GLPC fragment 28 cases). The remaining 56 cases (40.5%) had two coronal fragments. There is a high incidence of coronal fragments in intertrochanteric femur fractures when analyzed with 3D CT reconstructions. Our study suggests that these coronal fragments are difficult to identify on plain radiographs. Knowledge of the incidence and morphology of coronal fragments helps to avoid potential intraoperative pitfalls.     

The "optimal" burr hole position for endoscopic third ventriculostomy: results from 31 stereotactically guided procedures.

ETV is a well established and successful method in contemporary neurosurgery. With growing experience there is a more efficient patient selection and further advances in technical know how. We evaluated retrospectively a consecutive group of 27 patients who were treated in our institution by stereotactic guided ETV between 1992 and 1996. When reviewing their postoperative imaging studies (MRI/CT) we could measure the position of the burr hole as port of entry for the rigid endoscope in 17 out of 23 finally selected patients. The median lateral position was 28 mm (mean 26.5 mm) from the midline and 8 mm (mean 6.5 mm) anterior of the coronal suture. We conclude that the optimal burr hole position should be 3 cm lateral to the midline and 1 cm anterior of the coronal suture, in the patients with normal anatomical findings.     

垂体微腺瘤的诊断和治疗探讨

目的 探讨垂体微腺瘤（直径≤５ｍｍ）的诊断和治疗方法。方法 总结经ＣＴ垂体薄层扫描加矢,冠状重建诊断的垂体微腺瘤（直径≤５ｍｍ）２８例,全部采用经口鼻蝶窦入路显微手术切除。随访临床资料和内分泌改变,定期复查ＣＴ。结果 ２８例中病理证实２６例为垂体腺瘤,１例为炎症、１例为增生,诊断率达到９２．８％。汪变的术中定位成ＣＴ立体定位所见的位置完全符合。术后全部病例病情痊愈或好转,无手术死亡和并发症。２２例     

Coronal imaging to assess urinary tract stone size

PURPOSE: Urinary tract stones are typically measured using axial images from computerized tomography (CT). Such images provide a precise measurement of stone length and width. However, cephalocaudad dimensions can be difficult to determine from axial images. Coronal reconstructions, which can more accurately measure cephalocaudad dimensions, are seldom used to measure stones. We determined if coronal reconstructions could aid in more precisely determining stone size. MATERIALS AND METHODS: CT in patients who had undergone CT to evaluate urolithiasis at our institution during the 9-month period of January 2001 to September 2001 were reviewed. Length and width were measured using axial images, and cephalocaudad length and width were measured using coronal reconstructions. Cephalocaudad length was also estimated from axial images. Total area was calculated from axial and coronal reconstructions. The paired t test was used to assess statistical significance. RESULTS: The CT images of 102 patients with a total of 151 stones had undergone coronal reconstructions and, thus, were included in the study. Mean area in the axial and coronal reconstruction groups was 22.23 and 31.29 mm, respectively. Mean greatest axial dimension (length or width) was 4.87 mm and mean greatest coronal dimension (cephalocaudad length) was 6.51 mm. Cephalocaudad length estimated from axial images was 8.8 mm. Differences for all 3 of these comparisons (axial vs coronal area, greatest axial vs coronal dimension and estimated vs actual cephalocaudad length) proved to be statistically significant (p <0.0001). CONCLUSIONS: While urinary tract stones have typically been measured using axial images, coronal images provide a different impression of stone size. These data demonstrate that examining only axial images provides an inaccurate measure of stone size. We suggest that coronal images should also be used to measure more accurately stone size, which is critical for clinical decision making.     

Axial or coronal CT scan; which is more accurate in detection of open globe injury?

PurposeTo evaluate and compare the accuracy of axial versus coronal computerized tomography (CT) scan in detection of open globe injury.MethodIn this retrospective study, records of 61 patients with open and 72 patients with closed globe injury were reviewed. One experienced ophthalmologist and one neuroradiologist read the orbital CT scans and accuracy of the axial and coronal planes in detecting open globe injuries were compared. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated and compared for axial and coronal planes.ResultThe most common CT finding reported by the readers through the interpretation chart was scleral irregularity (70%), followed by dislocation of the crystalline lens (54%) and vitreous hemorrhage (51%). The sensitivity of axial, coronal and combined CT planes were 74%, 65%, and 79%, respectively. There was no significant difference between axial and coronal CT scans for detecting open globe injuries (P value=0.075), independent of the type and the location of the globe injury. For posterior injuries and sharp trauma, the sensitivity of coronal plane in detecting open globe injury was significantly lower, compared to axial and combined readings (P value=0.012 and 0.015, respectively). There was a near perfect agreement between readers for all CT scan readings with a Kappa value of 0.9.ConclusionAxial CT reading may be as adequate as a multiplanar reading in detection of open globe injury in emergency setting, where timely diagnosis matters. Without clinical and surgical findings, CT cannot provide adequate accuracy for detecting open globe injuries.     

Atlanto-axial lateral mass osteoarthritis. Three case reports and review of the literature

This report describes three cases of symptomatic unilateral C1-C2 mass osteoarthritis. The patients were all female aged 67, 62 and 59 years. One patient had a history of rheumatoid arthritis. Unilateral occipital pain was the main symptom. Neuroradiological work-up included open mouth anteroposterior radiograph, flexion/extension lateral radiograph of the cervical spine, CT scan with coronal and sagittal reconstruction and MRI. Findings allowed differential diagnosis with tumoral or infectious disease of upper cervical spine and ruled out C1-C2 instability. CT scan and MRI permitted precise operative planning by determining the course of vertebral artery in the C1 and C2 vertebrae. Two patients were treated by CT scan guided steroid injection. The third patient was treated by C1-C2 arthodesis after failure of conservative treatment.