Fracture detection in the cervical spine with multidetector CT: 1-mm versus 3-mm axial images

BACKGROUND AND PURPOSE: Multidetector CT imaging of the cervical spine performed with submillimeter collimation allows for the production of excellent quality multiplanar reformations and reconstructed axial images at any chosen section thickness. Currently there is no consensus on what images need to be reviewed for accurate diagnosis of cervical spine fractures. Our study assesses whether 1-mm axial images provide any diagnostic advantage over 3-mm images in detection of cervical spine fractures when read in conjunction with multiplanar reformations.MATERIALS AND METHODS: The dataset consisted 50 cases of CT of the cervical spine and included 25 consecutive cases of cervical spine fractures and 25 matched normal CTs. Axial images were reconstructed at 1- and 3-mm thicknesses, and the sagittal and coronal reformations between 2- and 3-mm thicknesses. Four radiologists reviewed all 50 of the cases twice, once at 1 mm and once at 3 mm. Reads were separated by 3 months.RESULTS: There were 39 fractures in total, consisting of 29 clinically significant and 10 insignificant fractures. Thirty-three fractures were missed in 400 reads. Twenty-one misses were at 3 mm (sensitivity, 86%), and 12 misses at 1 mm (sensitivity, 92%; P = .228). Ten of 33 misses were of clinically significant fractures, 6 misses at 1 mm and 4 at 3 mm (P = .52). Twenty-three of 33 misses were of clinically insignificant fractures, 6 at 1 mm and 17 at 3 mm (P = .006).CONCLUSION: For detection of clinically important fractures, there is no significant difference between 1- and 3-mm axial images when read in conjunction with multiplanar reformations.

Multidetector CT imaging of the cervical spine performed with submillimeter collimation allows for the production of excellent quality multiplanar reformations and reconstructed axial images at any chosen section thickness. The large image dataset and the ability to reconstruct a vast number of images leads to issues with data storage and time needed to review the examination. Currently there is no consensus on what images need to be reviewed for accurate diagnosis of cervical spine fractures. The standard in our institution is to read 1-mm axial images with sagittal and coronal reformations. The purpose of our study was to assess whether 1-mm axial images provide any diagnostic advantage over 3-mm images in the detection of cervical spine fractures when read in conjunction with multiplanar reformations, thereby providing objective data in the formulation of guidelines for the assessment of cervical spine CTs.     

Isotropic CT examination of abdomen and pelvis diagnostic quality of reformat

RATIONALE AND OBJECTIVES: To evaluate the image quality of axial and coronal reformats obtained from isotropic resolution abdomino-pelvic computed tomography (CT) examinations. MATERIALS AND METHODS: Thirty consecutive patients with intravenous contrast-enhanced abdomino-pelvic CT examinations (Brilliance 40, Philips Medical Systems, Cleveland, OH) were enrolled for the study. The raw data were reconstructed into two sets of source axial images: 0.9-mm slice widths with 0.45-mm reconstruction interval (isotropic resolution) and 4-mm slice widths with 3-mm reconstruction interval (anisotropic resolution: group A). Isotropic data set was reformatted into axial and coronal stacks (groups B and C, respectively) with 4-mm slice width and 3-mm interval. Three independent readers evaluated stacks A to C using a 3-point scale for resolution of hepatic vessels, edge sharpness of kidneys, respiratory motion artifact, reconstruction artifact, noise, and overall image quality. RESULTS: There was no statistical difference among the groups A to C for vessel resolution, motion artifact, noise, and overall quality. The scores given to group C were significantly lower than those to groups A and B for reconstruction artifacts. There was no difference among groups A to C for overall impression of image quality. The interreader agreements were excellent for axial images (groups A and B) and moderate for coronal reformats. CONCLUSION: Isotropic scanning of the abdomen and pelvis allows creation of reformats with similar image quality as similar thickness axial source images. These reformats are of sufficient quality to form the basis of clinical interpretation.     

螺旋 CT 容积扫描方法诊断胸廓骨及肋骨骨折的价值探讨

目的：探讨螺旋CT容积扫描诊断胸廓骨骨折的临床价值。方法笔者回顾性分析2011年1月～2014年6月拟诊断为胸廓骨及肋骨骨折患者80例的临床资料,男性49例,女性31例;年龄22～76岁,平均（40．2±2．3）岁。均具有完整X线片、3D图像和CT轴位扫描图像资料,并对X线、3D图像和CT轴位扫描图像的诊断结果进行对比分析。结果排除可疑骨折,以CT轴位扫描图像作为金标准,X线诊断的灵敏度为61．54％,特异度为66．67％;3D容积重建（ VR）诊断的灵敏度为98．59％,特异度为87．50％。结论螺旋CT可快速确诊胸廓骨及肋骨骨折,容积扫描中的容积再现法（ VR）、最大密度投影法（ MIP）和多平面重组法（ MPR）技术能较好显示细微骨折,在解剖空间结构上有较强优势。     

Multidetector computed tomography imaging of aortoenteric fistula

Three case reports illustrating multidetector computed tomography (CT) imaging findings of secondary aortoenteric fistula (AEF) are described and presented in axial sections, multiplanar reformats, and 3-dimensional reconstruction. Fistulae occurred in the early and late postgrafting period and involved both end-to-end and end-to-side aortic graft anastomoses. Multidetector CT is quick and accurate in the diagnosis of bleeding AEF.     

Multislice computed tomography in staging lung cancer: the role of multiplanar image reconstruction

OBJECTIVE: The role of multiplanar image reconstruction (MPR) in staging lung cancer was investigated using multislice helical computed tomography (CT), which allows high-quality volumetric imaging. METHODS: Forty-one consecutive patients with lung cancer (mean age = 71 years) underwent multislice CT of the thorax. The scans were acquired using contiguous 4-mm x 2.5-mm slices from the lung apex to the diaphragm in a single breath hold after injection of 100 mL intravenous contrast media. Contiguous axial, coronal, and sagittal images (5-mm slice thickness) were reconstructed in the lung and mediastinal windows. The axial images with and without multiplanar reformatted images were reviewed on a workstation on 2 separate occasions (a minimum of 6 weeks apart) by 2 experienced chest radiologists. The films were assessed for features relating to the primary lesion (size; location; and invasion of the chest wall, mediastinum, diaphragm, and/or fissures) and secondary features (mediastinal lymphadenopathy and lung metastases). The diagnostic confidence of each feature was expressed on a 4-point scale. RESULTS: A significant increase in confidence was seen on the part of both observers when diagnosing features relating to the primary lesion. The mean confidence score increased from 1.68 to 2.08 (P = 0.038) for observer A and from 1.50 to 1.80 (P = 0.020) for observer B. Confidence in assessing invasion of fissures was increased from 1.70 to 2.30 (P = 0.022) for observer A and from 1.67 to 2.27 (P = 0.006) for observer B. Improvement in interobserver agreement (kappa-value from 0.61 to 0.75) was observed with multiplanar reconstruction (MPR) in the assessment of tumor location. No statistical difference was demonstrated in the diagnosis of mediastinal lymphadenopathy or lung secondaries. CONCLUSION: Multiplanar imaging of the thorax is a useful supplementary tool in the staging of lung cancer, particularly in delineating the relation of the primary lesion to fissures and the diaphragm.     

Small bowel obstruction: the value of coronal reformatted images from 16-multidetector computed tomography--a clinicoradiological perspective

OBJECTIVES: To assess performance of 16-multidetector computed tomography for small bowel obstruction with surgery as standard of reference. To assess the impact of coronal reformats on reader confidence, and to address management perspective and surgeon's assessment of coronal images. MATERIALS AND METHODS: 16-Multidetector computed tomography scans of 30 patients presenting with clinical features of small bowel obstruction were reviewed. Five-millimeter axial images and 2.5-mm coronal images were available for interpretation. All patients had subsequent surgery. Two blinded readers independently reviewed axial and then coronal and axial (combination) images for transition site, etiology, and complications. Reader confidence was scored on a 3-point scale. A single surgeon evaluated studies for adequacy of scans and usefulness of coronal images. RESULTS: Results showed that the recorded accuracies were slightly higher for etiology, transition site, and complications using the combination data set; this reached statistical significance for etiology only (P = 0.08). There was no significant increase in scan evaluation time with addition of coronal images. Surgeon considered the coronal images more informative as compared with the axial images in 76.6% of cases. CONCLUSIONS: Coronal images generated at the scanner console are complementary to axials and improve reader confidence. Surgeons find coronal images more helpful than axial images for management.     

Determining the probability of detecting cervical spine fractures with computed tomographic scans using the visible human database

Cross-table lateral radiography alone is frequently unreliable for clearing of the cervical spine in cases of acute trauma. Computerized tomography (CT) is a standard procedure for detecting occult cervical spine fractures when cervical spine radiographs are equivocal or inadequate. There is evidence, however, that a significant number of fractures may still be missed by CT scans if too large a distance is used between scanning cuts in the axial plane. The purpose of this study was to determine the probability of detecting hidden fractures of the cervical spine over a wide range of fracture sizes and CT axial cut intervals. Digitized anatomic data of the cervical spine from the Visible Human Project^TM of the National Library of Medicine were used as a model template for the study. From a series analysis, it was determined that use of the standard 5-mm cut intervals missed 25–75% of fractures, depending on the size of the lesion. The 4-mm cuts were able to detect all of the 3-mm lesions but still missed a significant number of the smaller fractures. The probability of finding occult fractures at the 3-mm axial interval was 100% for all except the smallest fracture sizes. This mathematical analysis suggests that computerized tomography is a less than optimal method for detecting occult fractures of the cervical spine unless the cut interval is 3 mm or less. The addition of sagittal plane reconstruction of these images would further enhance the ability to detect subtle subluxations or fractures.     

Can independent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners be used for primary interpretation of MDCT of the abdomen and pelvis? A feasibility study

PURPOSE: To evaluate if coronal reformatted images can be used for primary interpretation of MDCT of the abdomen and pelvis using 64-slice MDCT. MATERIALS AND METHODS: IRB approval was obtained. We reviewed MDCT studies of the abdomen and pelvis of 220 consecutive patients performed with 64 row MDCT with constant scanning parameters. Based on a 0.625mm raw data set, transverse images were reconstructed at 5mm and coronal images at 3mm using standard reconstruction algorithms. Reader familiarity was achieved by simultaneous evaluation of transverse and coronal reformats in an initial group of 20 separate cases for findings in consensus. Two subsequent phases of image analysis were then performed in two groups of 100 patients each. In the first phase two radiologists evaluated the added utility of simultaneous review of MDCT of transverse and coronal reformatted images over transverse images alone in 100 consecutive patients referred for MDCT of the abdomen and pelvis. In the second phase, the same radiologists evaluated whether coronal multiplanar reformats could be used for primary interpretation of MDCT of the abdomen and pelvis in a separate but similar cohort of 100 consecutive abdominopelvic MDCT studies. The number of lesion(s), their location, size of smallest lesion, presence of artifacts and likely diagnosis were noted at each image interpretation. Image quality and confidence for interpretation was evaluated using five-point and three-point scale, respectively. The time required for primary interpretation of coronal reformats and transverse images were recorded. Statistical analysis was performed using Wilcoxon signed rank test. RESULTS: Both readers detected additional findings (n=37, 35), respectively, on simultaneous review of transverse and coronal reformats as compared with transverse images alone (p<0.001). Excellent interobserver agreement was noted (r=0.94-0.96). Both readers detected additional findings (n=62, 53), respectively, on independent review of coronal reformats as compared with transverse images alone (p<0.001). Readers' confidence was also found to be higher on coronal evaluations as compared to axial images (p<0.01). There was good interobserver agreement between the two readers. CONCLUSION: Independent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners show promise as the preferred orientation and can be useful for primary interpretation of MDCT of the abdomen and pelvis.     

16层螺旋CT肺血管造影在肺动脉栓塞诊断中的应用

目的　研究 16层螺旋CT肺血管造影在肺动脉栓塞诊断中的应用价值。方法　使用 16层螺旋CT扫描机 (SiemensSensation 16 )对临床拟诊肺栓塞的 4 9例患者进行前瞻性研究。采用层厚 3mm行胸部增强扫描。利用原始数据行层厚 1mm的轴面及多平面重建 (MPR)。比较层厚 3mm、1mm的轴面图像及MPR图像。结果　CT诊断肺栓塞 4 2例。病变共累及肺动脉 35 2支。对于主肺动脉及肺叶动脉栓塞 ,三种图像检出结果一致。但对于肺段及亚段动脉栓塞 ,层厚 1mm较 3mm显示率高 ,差异有显著意义 (P <0 0 1) ,1mm的MPR较轴面图像显示率高 ,但差异无显著性意义 (P >0 0 5 )。结论　 16层螺旋CT肺血管造影无创、快速、敏感性高 ,应当作为肺栓塞的首选检查方法。     

CT diagnosis of renal angiomyolipoma: the importance of detecting small amounts of fat

Six patients were reviewed who had renal angiomyolipoma (1.2-4.0 cm) in which only minimal amounts of fat were evident on CT. The fat content of the lesion was appreciated because tissue attenuation measurements of small areas of low attenuation within the tumors were performed and because thin-section (5-mm) and nonenhanced CT scans were used. The fat content of the lesions could be identified on 10-mm sections in three cases but only on 5-mm sections in three others. In two cases, fat was seen only on the nonenhanced 5-mm thin sections. Careful sampling of low-density regions within the mass must be performed because a single region of interest over the entire tumor will produce an average attenuation in the soft-tissue range. The use of 5-mm thin sections and thin, nonenhanced CT sections increases spatial and density resolution and decreases susceptibility to partial-volume effects. In a correlative study, no areas of fat were detected in a review of 100 well-circumscribed (4.0 cm or smaller) renal cell carcinomas. Detecting the existence of fat in a renal lesion will establish the diagnosis of angiomyolipoma and is the only radiologic finding that can differentiate it from renal cell carcinoma. Thus, unnecessary surgery will be avoided in these cases.     

Comparison of quality of multiplanar reconstructions and direct coronal multidetector CT scans of the lung

OBJECTIVE: The purpose of this study was to compare the quality of coronal multiplanar reconstructions with the quality of direct coronal thin-section multidetector CT (MDCT) scans. MATERIALS AND METHODS: Axial multidetector CT (MDCT) scans were obtained through the entire lung in 10 normal autopsy lung specimens using an MDCT scanner. Four protocols were used: 0.5-mm collimation with a 0.5-mm reconstruction interval; 0.5-mm collimation with a 0.3-mm reconstruction interval; 1-mm collimation with a 0.5-mm reconstruction interval; and 2-mm collimation with a 1-mm reconstruction interval. Multiplanar reconstruction images with 0.5-mm slice thickness were obtained from the four types of data sets. Direct coronal thin-section CT of the same 10 autopsy lung specimens was performed using 0.5-mm scan collimation, a 0.3-mm reconstruction interval, a 25.6-cm field of view, and a 512 x 512 matrix. Two independent observers compared the image quality of each of the four coronal multiplanar reconstruction sets with that of direct coronal thin-section CT scans. The observers analyzed visualization of anatomic features and artifacts. RESULTS: The total image quality of the multiplanar reconstructions obtained from 0.5-mm collimation data with or without 0.3-mm overlapping reconstruction was equal to that of direct coronal thin-section CT scans in all 20 interpretations. The image quality of multiplanar reconstruction images from 0.5-mm collimation data either with or without overlapping reconstruction was superior to multiplanar reconstruction images obtained from 1- or 2-mm collimation scans (p < 0.01, Fisher's exact test). Stairstep artifacts in multiplanar reconstructions using 0.5-mm collimation without overlapping reconstruction were equal to those with overlapping reconstruction and were fewer than those on 1- or 2-mm collimation (p < 0.01, Mann-Whitney U test). CONCLUSION: The image quality of coronal multiplanar reconstructions from isotropic voxel data obtained using 0.5-mm collimation, with or without overlapping reconstruction, is similar to that of direct coronal thin-section CT scans.     

Computed tomography pseudofractures of the mid face and skull base

Thin-section multislice CT delineates numerous normal skull-base and mid-facial bony discontinuities. These represent sutures, fissures and neurovascular foramina or channels, and should be differentiated from fractures. This pictorial review describes and illustrates the characteristic location and multiplanar CT appearances of these structures. Their clinical significance in terms of pathological processes and surgical planning are discussed.     

螺旋CT三维和多平面重建在髋臼骨折中的应用

目的 探讨螺旋ＣＴ（ＳＣＴ）三维和多平面重建在髋臼骨折中的临床价值。材料与方法 分析１６例髋臼骨折的轴位、多平面ＣＴ及三维ＣＴ表现。结果 表面重建（ＳＳＤ）对１４例超过２ｍｍ的骨折均很好显示,但对于２ｍｍ以下移位显示较差,多平面重建（ＭＰＲ）良好显示髋臼负重区的损伤及稳定性。结论 ＳＣＴ三维重建和ＭＰＲ对复杂的髋臼骨折的术前分类、指示手术入路及估计预后均有重要的临床意义。     

Value of CT volume imaging for optimal placement of radiofrequency ablation probes in liver lesions

PURPOSE: To determine the value of multiplanar and volume-rendered modes of analysis versus axial imaging for the optimal placement of probes in spiral image computed tomography (CT)-guided radiofrequency (RF) ablation of liver lesions. MATERIALS AND METHODS: Thirty-two malignant hepatic lesions in 21 patients with hepatocellular carcinoma (n = 10) or metastases (n = 11) were treated with percutaneous RF ablation. After axial CT-guided placement (biopsy mode) of the probe in the tumor, a contrast-enhanced spiral image set was obtained and data were viewed in contiguous axial sections and the multiplanar and volume-rendered modes. The position of the probe was characterized as "central," "marginal," or "outside," corresponding with its position in the lesion. Outside positioning was corrected before ablation was performed and, in cases of "marginal" positioning, the probe was redirected after initial ablative therapy in the same session. RESULTS: Multiplanar and volume-rendered analysis reclassified the needle position before 14 of 32 RF ablation procedures (44%; P =.0034, McNemar test). In 10 cases, probe positions considered "central" on biopsy-mode images were found to be "marginal" with multiplanar/volume-rendered analysis. In three cases, probe positions considered "marginal" on biopsy-mode images were found to be "outside" with multiplanar/volume-rendered analysis. In one lesion, multiplanar/volume-rendered analysis upgraded the probe position from "marginal" to "central." Comparison of multiplanar and volume-rendered analysis revealed no difference in probe positioning. The time requirements to obtain additional data were 159 seconds +/- 49 for multiplanar analysis and 434 seconds +/- 78 for volume-rendered analysis. CONCLUSION: A contrast-enhanced spiral CT image data set with multiplanar reformations to verify an optimal probe location after axial CT-guided needle placement should be obtained before RF ablation of liver lesions.     

Thin section dual-phase multidetector-row computed tomography detection of peritoneal metastases in gynecologic cancers

PURPOSE: To determine the sensitivity, specificity, and accuracy of multidetector-row computed tomography (CT) using thin sections and multiplanar reconstruction for the detection of peritoneal implants in patients with ovarian cancer. METHOD: Seventeen thin section dual-phase multidetector-row CT scans were performed on 17 women with potential peritoneal metastases from ovarian cancer, which scans were then followed by surgery. Axial and multiplanar images from the CT scans were reviewed by 2 observers, and the results were compared with the operative and clinical notes. RESULTS: Peritoneal metastases were detected by both readers in all 7 patients presenting with ovarian cancer and disease at laparotomy. Metastases were detected in 5/6 patients with recurrent tumor by observer 1 and in 4/6 patients by observer 2. Sensitivity, specificity, and accuracy for detecting peritoneal metastases at individual sites in the abdomen and pelvis were improved when both axial and multiplanar images were reviewed. Sensitivities were highest for the paracolic gutters and infracolic omentum (>70%). Approximately 50% of liver and diaphragmatic lesions were detected. Specificities approached 100% for all sites and accuracies were >80% for most sites of disease. CONCLUSION: The sensitivity, specificity, and accuracy of CT for peritoneal metastases in patients is high using thin slices and axial and multiplanar review of the data.     

MR findings in lipoma arborescens of the knee: our experience

PURPOSE: This paper describes the role of MR imaging in the identification of the different macroscopic patterns of lipoma arborescens. MATERIALS AND METHODS: Between June 1995 and January 2004, a total of 6387 MR examinations of the knee were retrospectively assessed for the presence of lipoma arborescens. The MR examinations were performed using a superconductive 0.5 T MR unit with a transmitting/ receiving coil dedicated for the extremities. The MR images were acquired with SE T1-weighted, GE T2-weighted and STIR sequences in sagittal, coronal and axial planes with 3-mm thickness and 1-mm gap. RESULTS: Lipoma arborescens was identified in 9 patients (mean age: 36 years). In 2/9 cases a localized lipoma arborescens was detected as a well-marginated single nodule on the suprapatellar bursa without irregularity or synovial hyperplasia. In the remaining 7 cases diffuse lipoma arborescens was identified on the wall of the suprapatellar bursa. In one case of diffuse lipoma arborescens there was involvement of both knees. In all cases the MR findings were verified at surgery and the final diagnosis was made by histological examination. CONCLUSIONS: MR imaging shows a high accuracy in the identification and characterization of lipoma arborescens, due to its multiplanar capabilities and high contrast resolution. MRI allows correct evaluation of size and grade, accurate treatment planning and effective follow-up, avoiding the need for synovial biopsy.     

MSCT斜轴位多平面重组图像在面神经管膝状窝及其周围骨折诊断中的价值

目的探讨MSCT扫描斜轴位MPR在面神经管膝状窝及其周围骨折中的诊断价值。方法收集经行颅中窝面神经减压手术证实的面神经管膝状窝或鼓室段近端骨折患者33例,回顾分析其术前CT图像,将术中所见与常规轴位、冠状位及斜轴位MPR图像所见对比。比较2种诊断模式(常规轴位及冠状位联合应用,常规轴位、冠状位及斜轴位MPR联合应用)对面神经管膝状窝及其周围骨折的诊断符合率。结果术前CT显示骨折线累及膝状窝或鼓室段近端22例(66.67%),其中常规轴位显示8例(24.24%),冠状位显示6例(18.18%),斜轴位显示20例(60.61%)。常规轴位或冠状位及斜轴位图像均能显示骨折线累及膝状窝或鼓室段近端10例,仅斜轴位显示12例,常规轴位、冠状位或斜轴位均不能显示11例。斜轴位MPR显示面神经管膝状窝或鼓室段近端局限性扩大26例(78.79%)。统计分析表明2种不同的诊断模式对膝状窝及其周围骨折诊断符合率有统计学差别。结论斜轴位MPR与常规轴位、冠状位图像联合观察可提高术前面神经管膝状窝及其周围骨折的诊断符合率。     

Three-dimensional fracture visualisation of multidetector CT of the skull base in trauma patients: comparison of three reconstruction algorithms

The purpose of this study was to retrospectively assess the detection rate of skull-base fractures for three different three-dimensional (3D) reconstruction methods of cranial CT examinations in trauma patients. A total of 130 cranial CT examinations of patients with previous head trauma were subjected to 3D reconstruction of the skull base, using solid (SVR) and transparent (TVR) volume-rendering technique and maximum intensity projection (MIP). Three radiologists independently evaluated all reconstructions as well as standard high-resolution multiplanar reformations (HR-MPRs). Mean fracture detection rates for all readers reading rotating reconstructions were 39, 36, 61 and 64% for SVR, TVR, MIP and HR-MPR respectively. Although not significantly different from HR-MPR with respect to sensitivity (P?=?0.9), MIP visualised 18% of fractures that were not reported in HR-MPR. Because of the relatively low detection rate using HR-MPRs alone, we recommend reading MIP reconstructions in addition to the obligatory HR-MPRs to improve fracture detection.     

Comparison of 4 computed tomographic imaging protocols for lateral tibial plateau fractures.

OBJECTIVE: Many computed tomographic (CT) imaging protocols are used for pretreatment assessment of tibial plateau fractures. This study compares the diagnostic capabilities of 4 CT protocols. METHODS: Lateral tibial plateau fractures were induced in 19 knee specimens and CT scans were obtained with the following protocols: 1) 3-mm collimation, axial acquisition, 2) 3-mm collimation, helical acquisition, 3) mixed-increment collimation, axial acquisition, and 4) 3-mm collimation, helical acquisition with 50% overlap reconstruction of raw data. Two-dimensional coronal and sagittal reformations and 3-dimensional surface reconstruction images were analyzed for maximum fragment depression, peripheral fragment displacement, fracture pattern classification and quality of image. Specimen dissection established maximal articular surface depression, fragment displacement and actual fracture pattern. RESULTS: None of the 2-dimensional reformations from the 4 protocols proved statistically superior for determining maximal fracture depression, fragment displacement, or fracture classification. There was a trend toward more accurate fracture classification with the mixed-increment axial protocol and the overlap protocol than either of the 3-mm protocols, but this was not statistically significant. All protocols were statistically equivalent in predicting fracture pattern classification using 3-dimensional images. However, the 3-dimensional images were of significantly higher quality when obtained with either the mixed-increment axial protocol or the overlap protocol. CONCLUSIONS: There were no statistically significant differences in the objective assessment of tibial plateau fractures among the 4 different protocols. The 3-dimensional images derived from the mixed-increment axial protocol and the 3-mm helical protocol with 50% overlap reconstruction were of superior quality.     

"Buckle" rib fracture: an artifact following cardio-pulmonary resuscitation detected on postmortem CT

Buckle rib fractures are incomplete fractures involving the inner cortex alone, and are rarely detected on routine chest X-ray or at autopsy. The characteristics of these fractures have not been well evaluated in situ although they are commonly observed on postmortem CT images especially following CPR. The postmortem CT findings in 42 cases showing buckle rib fractures caused by CPR were reviewed. The cause of death in all cases was non-traumatic. The shape, number, location, and distribution of these buckle rib fractures and their relationship to other types of rib fractures were evaluated using a novel oblique axial multiplanar reconstruction technique. Almost all incomplete rib fractures associated with CPR are buckle rib fractures (90.5%). All rib fractures were distributed from the second to ninth ribs with over 95% being within the second to seventh ribs. Buckle rib fractures are dominant in the seventh to ninth ribs and the proportion of buckle rib fractures located in the vicinity of the costochondral junctions increases with the lower ribs. Over 97% of all CPR associated rib fractures are located in the anterior one third of the ribs based on a new measurement method utilizing oblique axial multiplanar reconstruction of the CT data. When recognition of incomplete or buckle rib fractures on postmortem CT is taken into account, detection of symmetry and continuity of rib fractures typically associated with CPR is improved compared with the detection of complete fractures alone. Recognition of buckle rib fractures and their characteristics on postmortem CT is of benefit to the forensic pathologist in evaluating the possibility of CPR and the differentiation of resuscitative artifact from forensically significant visceral injury observed at autopsy.