Axial CT Sections Research Articles

Small-Bowel Mucormycosis at Dual-Energy CT.

HomeRadiologyVol. 307, No. 5 PreviousNext Reviews and CommentaryFree AccessImages in RadiologySmall-Bowel Mucormycosis at Dual-Energy CTLoic Demir, Paul Calame Loic Demir, Paul Calame Author AffiliationsFrom the Department of Radiology (L.D., P.C.) and EA 4662 Nanomedicine Laboratory, Imagery and Therapeutics (P.C.), University of Bourgogne Franche-Comté, CHRU Besançon, 3 boulevard Alexandre Fleming, 25030 Besançon, France.Address correspondence to P.C. (email: [email protected]).Loic DemirPaul Calame Published Online:Jun 20 2023https://doi.org/10.1148/radiol.223271MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Supplemental material is available for this article.A 22-year-old woman with acute myeloid leukemia was treated with allograft and immunosuppressants. Five days later, she developed abdominal pain and underwent CT of the abdomen, which showed isolated small-bowel wall thickening with normal enhancement. A second CT examination was performed 3 days later due to worsening febrile abdominal pain; this examination showed diffuse small-bowel wall thickening. Dual-energy CT images showed focal defects of the normal small-bowel mucosal enhancement suggestive of nonperforated necrotizing infectious enterocolitis (Figure, Movie). She underwent small-bowel resection. Pathologic analysis of resected samples showed focal areas of transmural necrosis due to multiple vascular mycotic thrombi (Figure).Images in a 22-year-old female patient with a primary history of allograft-treated acute myeloid leukemia complicated by mucormycotic ulcerative-necrotic enterocolitis. (A) Conventional and (B) iodine density images in the same axial section of the portal phase of abdominal CT. The dual-energy CT images show dilatated small bowel (★) associated with a lack of wall enhancement (arrowhead), which contrasts with the adjacent hyperenhanced mucosa (arrow). (C) A photograph of the gross small-bowel resection specimen shows focal ileal ischemic ulceration (arrowheads).Download as PowerPointOpen in Image Viewer Get the Flash Player to see this video.Movie: Movie file of iodine density merged with virtual noncontrast in axial CT sections. The scale shows iodine concentration in milligrams of iodine per milliliter. A = anterior, F = front, L = left, P = posterior, R = right.Download Original Video (19.0 MB)Mucormycosis is caused by fungi of the subphylum mucoromycotina, which are zygomycetes that invade vessels, causing thrombosis and eventually parenchymal necrosis. Small-bowel mucormycosis is the least common site; mortality is high (1). Mucormycosis may mimic ischemic bowel (2,3). Dual-energy CT improved bowel wall visualization and highlighted the defects in the mucosa readily, which expedited surgical management—a key prognostic point (1).Disclosures of conflicts of interest: L.D. No relevant relationships. P.C. No relevant relationships.

Association of Computed Tomography Values of the Tooth Root and Alveolar Bone with Orthodontic Root Resorption

This study aimed to evaluate the effect of CT values of the tooth root and bone on root resorption using data obtained before and after orthodontic treatment. Forty-one patients with jaw deformities were divided into those with and without root resorption （n = 18 and 23, respectively）. The distance from the anatomical root apex to the edge of the incisive canal was measured using axial CT sections before active treatment. The distance from the anatomical root apex to the labial and palatal cortical bone and the CT values of the root and alveolar bone were measured and compared using sagittal CT sections. The tooth axis and vertical and lateral movements of the maxillary right central incisor were examined using lateral cephalograms before and after treatment. Root resorption group showed significantly higher CT values of alveolar bone than the control group and different axial movement of the root apex and distance between the labial cortical bone and root apex on lateral cephalograms. The risk of root resorption increased with an increase in the CT values of the alveolar bone surrounding the maxillary central incisor. The horizontal movement of the root apex was associated with the distance between the labial cortical bone and root apex, and root resorption during maxillary central incisor movement.

Diagnostic accuracy of Non-ECG Gated Chest CT (NEGCT) for cardiac chambers’ dimensions in comparison with echocardiography

Objective: To analyze the accuracy of Non-ECG Gated Chest CT (NEGCT) for cardiac chambers’ dimensions, keeping Echocardiography as the gold standard.
 Methods: After IRB approval, all patients that underwent concurrent contrast chest CT/CTPA and transthoracic 2D echocardiography exam at our institute within 1 month interval comprised the study population. Data was archived from HMIS PACS Database. The sizes of right ventricle (RV), left ventricle (LV) and left atrium (LA) was recorded in shot axis at axial CT sections and at echocardiography. RV and LV-transverse diameter was measured at basal third of the heart, from the inner to inner myocardium perpendicular to the inter-ventricular septum and LA-max. Anterior-posterior dimension was measured at the level of the aortic root.
 Results: Total 213 subjects were studied, with average age of 52.1±15.8 years. The CT-Echocardiography measurement concordance rates were significantly high for LA, LV and RV measuring 93.8%, 96.7% and 69.01% respectively. Using CT threshold for LA, LV, RV enlargement > or equal to 45, 55, 35mm, the AUC via ROC curve analysis was estimated to be 0.912, 0.992, 0.650 respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of NEGCT was found to be 66.67%, 95.10%, 37.5%, 98.5% and 93.90% for LA; 100%, 96.67%, 30.0%, 100%, 96.7% for LV and 33.33%, 74.86%, 17.86% 87.26% and 69.01% for RV respectively.
 Conclusion: Overall, the accuracy of chamber dimensions at NEGCT was excellent with high CT-Echocardiography concordance, making it an alternative modality for examining chamber sizes, in the absence of cardiac MRI. Through it, a radiologist can also add more value to CT reporting.
 Keywords:
 Echocardiography, NEGCT, Dimensional Measurement

Application of landmark guided screw in ankle syndesmos diastasis surgery

Objective: Screw used in the treatment of ankle syndesmosis diastasis can be placed in malposition. Our aim in the study is to define a new technique for sending the screws in the right direction. Material and Methods: The ankle tomography of 188 patients was evaluated. First, the medial malleolus root was divided into three equal parts in axial CT section. Then, a screw model was drawn to fit the fibula to the concave surface in the tibia in another axial CT section where the syndesmosis joint is prominent.These two axial CT sections were placed on top of each other with computer program. Results are noted Results: While 95.7% of the screw simulations were passing through the front 1/3, 4.3% through the middle 1/3, the screw did not pass through the rear 1/3 in any simulation. 187 of these lines passed between the most lateral peak of the fibula and 3 mm posterior. Conclusion: During diastasis surgery, the insertion site of the drill should be chosen between the sharp peak of the fibula and the 3mm posterior. When the drill is placed in this way and directed 1/3 anterior to the medial malleolus, our screw will be sent in the correct position. Our study revealed that the surgical treatment of syndesmos dissociation with screws is a landmark independent of the patient's position and the skill of the surgeon. There is no other study like this study. However, considering the consistency of our results with the literature, we believe that our study can guide surgeons in practical applications

The relationship between anatomical variations and paranasal sinus volumes with climate and altitude

The aim of this study was to evaluate the effect of climate and altitude differences on the volume of paranasal sinuses and on the frequency of anatomic variations by comparing the paranasal sinus computerized tomography (PNSCT) of patients who were born and living in a cold, dry climate at high altitude with those of patients who were born and living on the coast at sea level in a temperate climate. We also aimed to determine differences relating to gender. Axial and coronal CT sections were used for volume measurements in the paranasal sinuses. For measurements, the widest view of the sinuses was used. The findings of this study have shown that age groups and genders compared measurements between the two cities. When the age groups are examined, there is no significant difference between the regions between 0-20 years of age (p> 0.05), whereas 21-40,41-60,61 and above individuals have a significant difference between the frontal and sphenoid sinuses (p 0.05). Besides, when the diameter of the paranasal sinuses between regions is examined; It was found that individuals in Adana were longer than Sivas (p

Peroneal artery safe zone in the posterolateral approach to the distal tibia: A CT angiogram based anatomical study

ObjectivesThe posterolateral approach to the distal tibia is commonly used for stabilisation of ankle fractures as it allows good visualisation and direct reduction of the posterior distal tibia and malleolar fragments. This approach can also be used for internal fixation of an associated lateral malleolus fracture. The aim of our study is to describe the surgical anatomy of the peroneal artery (PA) in relation to the tibial plafond and the distal fibula; thereby suggesting a safe zone during proximal dissection of posterolateral approach. MethodsUsing Computed Tomography Angiographic (CTA) study, the course of the PA in relation to the tibial plafond and distal fibula was analysed in 142 lower limbs (bilateral limbs of 71 adult patients; 43 males and 28 females). Axial, coronal, and sagittal CT sections were cross-linked to specify the position of the PA. The PA course was identified and the level of its distal bifurcation over the tibia was marked. Perpendicular measurements were made from this point to the tibial plafond and tip of distal fibula. ResultsThe PA bifurcated distally at mean 58.3±24.2mm (SD) (range: 37.0–115.0mm) proximal to the right tibial plafond and mean 81.9±24.4mm (range: 54.0–137.0mm) from the right distal fibular tip. In the contralateral side, the PA bifurcated at mean 57.9±23.3mm (range: 36.0–125.0mm) proximal to the left tibial plafond and 81.8±23.9mm (range: 54.0–147.0mm) from the left distal fibular tip. The difference between the right and the left side of distal bifurcation point diameter of the same patient was assessed, range (0.0–58.0mm) with median 2.0mm and IQR 10.0mm. Three different PA vasculature patterns were identified. ConclusionsIt is important for surgeons to be aware of the surgical anatomy of PA to avoid inadvertent injury during posterolateral approach to distal tibia. The PA may bifurcate as close as 36mm from the tibial plafond with possible variation bilaterally. Therefore, special attention needs to be considered by the operating surgeon while dissecting in this region due to the wide anatomical variation in vasculature. However, once the PA is mobilised, any fixation modality including posterior buttress plate could be safely performed.

The effect of bone mineral density on development of Schmorl's nodes in young patients.

The aim of this study was to detect the relationship between the development of Schmorl's nodes (SNs) and bone mineral density (BMD) in young patients. Computerized tomography (CT) images of the thoracolumbar vertebral column were retrospectively examined by two experienced radiologists for SNs. The diagnostic criterion for SN was defined as a node size larger than one-third but not more than two-thirds of the relevant vertebral endplate. Considering the eligibility criteria, a total of 74 individuals (60 males and 14 females; mean age: 24.3 years; age range: 18-40 years) with SN at the thoracolumbar vertebrae were included in the patient group, and a total of 38 age- and gender-matched individuals (30 males and 8 females; mean age: 25 years) with no evidence of SN were included in the control group. All these individuals were younger than 40 years. In the patient group, SNs were assessed in terms of the distribution of the thoracolumbar vertebrae, the location of the upper and lower endplates, and the total number of lesions. In all individuals included in the study, BMD was measured from the axial CT sections by quantitative CT and then compared between the two groups. The distribution of age and gender was comparable between the two groups (p=0.438). A total of 208 SNs were identified in the patient group. Of these, 92 (44%) were located at the thoracic vertebrae and 116 (56%) at the lumbar vertebrae. The mean BMD was 131.6 g/cm3 in the patient group and 140.7 g/cm3 in the control group (p=0.03). There was no significant relationship between the total number of SNs per patient and the mean BMD (p=0.156). Evidence from this study revealed that low BMD may be a predisposing factor for the development of SNs in patients younger than 40 years. Level III, Diagnostic Study.

P1.06-04 Deep Learning-Based Segmentation of Mesothelioma on CT Scans: Application to Patient Scans Exhibiting Pleural Effusion

Tumor volume has been a topic of interest in the evaluation of treatment response, staging and prognosis of malignant pleural mesothelioma patients. Many mesothelioma patients present with or develop pleural fluid, the presence of which may complicate tumor segmentation on CT scans. We implemented a method for the automated segmentation of mesothelioma tumor on CT that explicitly excludes pleural effusion, which, if included in the segmentation of tumor, could confound the assessment of tumor volume. Deep convolutional neural networks (CNNs) were trained for the segmentation of mesothelioma tumor in each hemithorax. A database was collected of 180 CT scans of 160 mesothelioma patients who exhibited tumor and pleural effusion. 6026 axial sections containing segmented tumor (1243 sections exhibiting pleural effusion) from 134 chest CT scans were used to train deep CNNs for segmentation of mesothelioma tumor. A radiologist contoured tumor on a test set of 94 axial sections that exhibited both tumor and pleural effusion; these sections were randomly selected from 46 CT scans of 34 patients not included in the training set. Performance was evaluated on the test set by calculating the Dice Similarity Coefficient (DSC) between computer-generated and reference segmentations; DSC is a measure of overlap between a pair of segmentations (a value of 0 indicating no overlap, 1 indicating complete overlap). We compared the performance of the present method to a previously published deep learning-based method for the automated segmentation of mesothelioma tumor on CT scans; differences in DSC values achieved on the test set by the two methods were assessed through a two-tailed paired Wilcoxon signed-rank test. A boxplot of DSC values achieved on the test set by the current method and the previously published method is shown in Fig. 1. The median DSC on the test set achieved by the current method was 0.66 (inter-quartile range 0.20); the median DSC on the test set achieved by the previously published method was 0.51 (inter-quartile range 0.34). The difference in DSC between the two methods was statistically significant (p < 0.0001). A deep CNN was implemented for the task of automated segmentation of mesothelioma tumor on CT scans of patients who also exhibit pleural effusion. The present method achieved a statistically higher overlap (p <0.0001) with radiologist-provided reference contours than a previously published method on a test set of 94 axial CT sections of mesothelioma patients exhibiting both tumor and pleural effusion.

Identification of the medial femoral safe zone for drilling during dynamic hip screw side plate fixation: A CT angiogram tracing of the profunda femoris artery

ObjectivesIatrogenic injury of the Profunda Femoris Artery (PFA) at time of hip fixation surgery can increase morbidity and mortality and prolong the hospital stay. This is an injury that tends to pass unnoticed as a cause of postoperative deterioration despite being frequently reported in the literature. Our study aims to describe the anatomy of the PFA in relation to the medial femoral cortex with specific emphasis on its orientation relative to the position of a sliding hip screw side plate construct. By doing so we are able to present clear guidance to orthopaedic surgeons on how to avoid iatrogenic PFA injury at the time of hip fracture fixation. MethodsUsing Computed Tomography Angiographic (CTA) studies, the course of the PFA in relation to the medial femoral cortex was traced in 44 patients (28 males and 16 females) with mean age of 65.6 years. Coronal and axial CT sections were cross-linked to specify the position of the PFA at 1 cm intervals. ResultsThe course of the artery could be divided into three parts relative to a fixed reference point. Proximal and distal parts of the artery were in a safer position in comparison to the middle part of the artery that was found very close to the femoral cortex and along the coronal axis of the femur (mean angle 2.9° from the femoral coronal axis and 13.8 mm from the medial femoral cortex). Using the commercially available side plate constructs, this part of the artery corresponded to the distal part of the plate (third and fourth holes). ConclusionSpecial attention needs to be practiced by the operating surgeon while drilling into the third and fourth holes of the side plate.

Medico-Legal Implications of C1 Vertebral Fractures. Case Report

Abstract Introduction: The upper C1-C2 column is the subject of several erroneous diagnostics. The most common mechanisms of injuries include fall from high-impact skulls, car accidents, etc. Vertebra C1 can also be injured by mild trauma. The Japanese show that atlas fractures occur in about 2-13% of the cervical spine fractures and about 1.3% of the total spinal cord injuries. It is underlined that CT examination is the most useful diagnostic method. The Czechs show that the atlas lesions appear in 1-2% of the cervical spine lesions. Americans reported fracture of the atlas in 7% of the cervical spine fractures. Even if CT has shown its value, lateral radiography is recommended in C1-C2 fractures. When victims are children or people injured in high-speed car crashes, the reported mechanisms were the fall from a high level and the impact on the tip of the flexed skull. The Italians mention that the C1-C2 area is the most exposed diagnostic area with errors. Material and methods: given the difficulty of establishing a diagnosis of C1 type fractures, we present in this paper such a case. We highlight the value of a CT scan. The victim is a 26-year-old woman with a trauma from the wall. The main issue in this case is that the diagnosis made by the radiologist seems to be wrong, the electronic and imprinted copies are of inferior quality. A second opinion revealed a very fine fracture that seemed to come from an older date than the date when the victim claimed she was assaulted. The better the lesions, the more misleading the interpretations. Any imaginary imaging lesion, especially if it is obvious in electronic reconstructions, must be brought to the attention of the physician if they are taken into account by "image". The axial CT sections may omit some lesions under certain conditions, for example at the upper and lower poles of a spherical, ovoid or cubic structure, such as the atlas lateral mass. Conclusions: the diagnostic solution in this case is the reconstruction of the axial sections in several planes. The crack can be highlighted, in the case of a reconstructed image, only after stacking the axial images. The mechanism could be through sudden compression, during a sudden head movement, uninitiated and uncontrolled by the neck muscles, when a movement occurs over the degree of elasticity of the occiput-atlas joint, the occipital condyles compressing abruptly, unilaterally one of the atlas masses. In such clinical cases, we experience pain, muscle contraction and torticollis, on a normal neurological background.

The CT Swirl Sign Is Associated with Hematoma Expansion in Intracerebral Hemorrhage.

Hematoma expansion is an independent determinant of poor clinical outcome in intracerebral hemorrhage. Although the "spot sign" predicts hematoma expansion, the identification requires CT angiography, which limits its general accessibility in some hospital settings. Noncontrast CT, without the need for CT angiography, may identify sites of active extravasation, termed the "swirl sign." We aimed to determine the association of the swirl sign with hematoma expansion. Patients with spontaneous intracerebral hemorrhage between 2007 and 2014 who underwent an initial and subsequent noncontrast CT at a single center were retrospectively identified. The swirl sign, on noncontrast CT, was defined as iso- or hypodensity within a hyperdense region that extended across 2 contiguous 5-mm axial CT sections. A total of 212 patients met the inclusion criteria. The swirl sign was identified in 91 patients with excellent interobserver agreement (κ = 0.87). The swirl sign was associated with larger initial hematoma (P < .001) and earlier initial CT (P < .001) and hematoma expansion (P = .028). Multivariable regression modeling demonstrated that if one assumed similar initial hematoma volume, onset-to-first scan, and time between CT scans, the median absolute hematoma growth was 5.77 mL (95% CI, 2.37-9.18 mL; P = .001) and relative growth was 35.6% (95% CI, 18.5%-52.6%; P < .001) higher in patients with the swirl sign compared with those without. The NCCT swirl sign was reliably identified and is associated with hematoma expansion. We propose that the swirl sign be included in risk stratification of intracerebral hemorrhage and considered for inclusion in clinical trials.

Acetabular Anteversion with CT in Supine, Simulated Standing, and Sitting Positions in a THA Patient Population

Appraisal of the orientation of implants in THA dislocations currently is based on imaging done with the patient in the supine position. However, dislocation occurs in standing or sitting positions. Whether measured anteversion differs in images projected in the position of dislocation is unclear. We compared measured acetabular cup orientations on axial CT scans taken with the patient in a supine position with those from CT sections at angles to the sacral slope reflecting standing and sitting positions. We retrospectively reviewed the radiographs of 328 asymptomatic patients who had THAs. Anatomic acetabular anteversion (AAA) was measured from the plain CT scan (supine position, axial CT sections). The AAA also was measured on reformatted CT scans in which the orientation was adjusted individually to the sacral slope on lateral radiographs with patients in the standing and sitting positions. The mean/(SD) AAA changed from 24.2° (6.9°) in the supine position to 31.7° (5.6°) and 38.8° (5.4°) in simulated standing and sitting positions, respectively. The supine AAA correlated with the standing AAA (r = 0.857) but not with the sitting AAA (r = 0.484). These data suggest measurement of the AAA on a plain CT scan used in current practice is biased. In patients with recurrent posterior dislocation from a sitting position, accounting for the functional variations in measurement of the position of the acetabular cup provides more relevant information regarding component positioning.

Evaluation of thoracic pedicle screw placement in adolescent idiopathic scoliosis

Pedicle screw fixation is a challenging procedure in thoracic spine, as inadvertently misplaced screws have high risk of complications. The accuracy of pedicle screws is typically defined as the screws axis being fully contained within the cortices of the pedicle. One hundred and eighty-five thoracic pedicle screws in 19 patients that were drawn from a total of 1.797 screws in 148 scoliosis patients being suspicious of medial and lateral malpositioning were investigated, retrospectively. Screw containment and the rate of misplacement were determined by postoperative axial CT sections. Medial screw malposition was measured between medial pedicle wall and medial margin of the pedicle screw. The distance between lateral margin of the pedicle screw and lateral vertebral corpus was measured in lateral malpositions. A screw that violated medially greater than 2 mm, while lateral violation greater than 6 mm was rated as an "unacceptable screw". The malpositions were medial in 20 (10.8%) and lateral in 34 (18.3%) screws. Medially, nine screws were rated as acceptable. Of the 29 acceptable lateral misplacement, 13 showed significant risk; five to aorta, six to pleura, one to azygos vein and one to trachea. The acceptability of medial pedicle breach may change in each level with different canal width and a different amount of cord shift. In lateral acceptable malpositions, the aorta is always at a risk by concave-sided screws. This CT-based study demonstrated that T4-T9 concave segments have a smaller safe zone with respect to both cord-aorta injury in medial and lateral malpositions. In these segments, screws should be accurate and screw malposition is to be unacceptable.

Computed Tomography-Bronchoscopic Simulation for Guiding Transbronchial Fine Needle Aspiration of Extramural Targets: A Phantom Study

Extramural paratracheal/-bronchial tumors of the mediastinum and the hilum that cannot be seen in bronchoscopy constitute a particular challenge for transbronchial fine needle aspiration cytology. A software prototype was developed as a guidance tool to visualize extramural targets on computed tomography (CT)-bronchoscopy. A phantom study was conducted to evaluate this guidance tool. For CT-bronchoscopic simulation extramural targets are visualized behind the semitransparent wall in the endoluminal view. An airway phantom with 16 targets was examined by 3 bronchoscopists. In a first pass the targets were bronchoscopically punctured in the conventional way only with knowledge of axial CT-sections. In a second pass guidance by CT-bronchoscopic simulation was used. A postinterventional CT scan of the phantom was conducted to analyze the spatial relationship between the marked puncture sites and the targets. The punctures were classified in hits and failed punctures due to deviation in distance and angle. The total hit rate of the 3 operators was significantly higher with CT-bronchoscopic simulation (32 of 48) than with the conventional method (14 of 48; P < 0.01). Concerning the failed punctures the deviation in distance and angle was significantly smaller with CT-bronchoscopic simulation (P < 0.01, P < 0.05, respectively). CT-bronchoscopic simulation significantly increased hit rate of bronchoscopic punctures of extramural lesions compared with conventional orientation using axial CT-sections in this phantom study. These results suggest that CT-bronchoscopic simulation might be a valuable tool for increasing yield and accuracy of bronchoscopic transbronchial fine needle aspiration in patients with mediastinal and hilar masses that are invisible for conventional bronchoscopy.

Transitional Patterns of the Zygapophyseal Joints at the Thoracolumbar Region

The level and rate of anatomical changes in the orientation of zygapophyseal joints (ZJs) from the thoracic to the lumbar type is a matter of controversy. So, in this study the superior articular facets of ZJs at the thoracolumbar region were investigated for any deviation from the typical thoracic or lumbar criteria. The study included 20 macerated vertebral columns and axial CT sections on 20 healthy adult subjects. Out of the present results three main types of transitional facets could be differentiated: Coronally oriented Divided facets with the medial surface coronally oriented while the lateral surface was facing posterolaterally Lumbar like with less sagittalization and less concavity. Bilateral asymmetry was found to be a common feature. According to the number of ZJs with atypical facets, three main patterns of orientation changes could be elucidated. Gradual pattern (75%) where there was one coronally oriented ZJ, More gradual type with 2 successive atypical ZJs (10%), Sudden pattern (15%) where the transition occurred over one vertebra as its superior facet was thoracic and the inferior facet was lumbar in type. The process of transition of orientation was found to occur between T10-L1 but most commonly between T11,12. Further study is needed to document the assumption that these patterns of normal variations may be related to the predisposition of low back pain or even disc prolapse.

The role of retrocolonic saline injection to obtain access for percutaneous nephrostomy in a pelvic kidney

tests showed a random sugar level of 2.3 g/L and creatinine of 14 mg/L. Abdominal ultrasonography showed a malrotated pelvic left kidney and gross hydronephrosis with internal debris. A diagnosis of pyonephrosis of the malrotated left kidney was made, based on the presentation and the ultrasonography findings. The patient was referred for PCN drainage. CT showed a horizontally lying kidney in the midline at the level of the L4/5 vertebral body, with the renal pelvis directed antero-superiorly and to the right. There was a grossly distended pelvicalyceal system and thinning of renal parenchyma suggestive of PUJ obstruction (Fig. 1). There was no evidence of calculi. However, there was no suitable access to reach the left kidney because of the descending colon anteriorly and the left iliac bone posteriorly. It was planned to displace the descending colon anteriorly by a retrocolonic saline instillation and to obtain an access for PCN.The procedure was done under local anaesthesia and sedation, with the patient in the right lateral position. Axial CT sections were obtained and a suitable level (shortest distance, transrenal parenchymal, retroperitoneal approach) selected (Fig. 2). With strict aseptic precautions, a 7-cm, 21 G needle was placed horizontally from the left side behind the distal descending colon and in front of the left iliac bone (Fig. 3). Then a120 mL of normal saline was instilled in the retroperitoneal space after confirming the needle position by CT fluoroscopy. Check CT showed anterior displacement of the descending colon by > 2 cm (Fig. 4a,b). A 15-cm, 21 G needle was passed along this track into the renal pelvis through the upper pole calyceal region, and pus was aspirated. A 0.9 mm guidewire was initially passed and subsequently changed for a 0.9 mm Amplatz wire using an Accustick dilator system. A 10 F pigtail drainage catheter was placed and connected to a urine bag for dependent drainage (Fig. 5).Sample culture showed Gram-negative bacilli and the patient was kept on antibiotics with supportive therapy. She showed a significant clinical improvement within a few days and underwent elective left nephrectomy 2 months later.

CT findings in involvement of the paranasal sinuses by lepromatous leprosy.

The role of nasal infection in the transmission of leprosy has been extensively studied. Leprosy can affect the paranasal sinuses due to mucosal continuity and bacillaemia. This prospective study was performed on 25 untreated patients with lepromatous leprosy. 5 mm contiguous axial and coronal CT sections of paranasal sinuses, on soft tissue and bone windows, were obtained in all patients. Each sinus was examined for mucosal thickening, soft tissue densities and bony outlines. Representative biopsies were taken from ethmoid sinus to confirm the radiological diagnosis in 12 patients with multiple paranasal sinus involvement. Ethmoid aircells were involved in 20 patients (80%). Maxillary, frontal and sphenoid sinuses showed abnormalities in 12, four and three patients, respectively. The ethmoid biopsy showed involvement by lepromatous leprosy in seven of 12 patients (58.3%). Involvement of paranasal sinuses is common in lepromatous leprosy and is of considerable epidemiological significance.

Dreidimensionale Rekonstruktionsverfahren in der lumbalen Computertomographie

In this study, 50 patients were examined by a Siemens' "Somatom Plus"; continuous 2 mm sections between the third lumbar and first sacral vertebra were obtained. The accuracy of the 3-D reconstruction software programme was checked by measuring a polyethylene phantom of a second lumbar vertebra. Reconstruction was carried out with a threshold definition of 150 Hu. In each case, four standard projections and medio-sagittal, medio-lateral and coronary sections were reconstructed, photographed and compared with axial CT sections and conventional radiographs. All these imaging procedures were suitable for the diagnosis of osteochondrosis and chondrosis. Spondylosis was diagnosed more frequently on 3-D CT. Spondylarthrosis, with narrowing of the intervertebral foramina and root canals is shown particularly well by 3-D CT, since the entire extent of these structures can be seen. 3-D surface reconstruction of the lumbar spine is useful in the diagnosis of lumbar spondylarthrosis with narrowing of the root canals and of the spinal canal. This method of axial Ct is superior to conventional radiography of the lumbar spine in the usual two planes.

Direct sagittal CT in the evaluation of temporal bone disease.

The human temporal bone is an extremely complex structure. Direct axial and coronal CT sections are quite satisfactory for imaging the anatomy of the temporal bone; however, many relationships of the normal and pathologic anatomic detail of the temporal bone are better seen with direct sagittal CT sections. The sagittal projection is of interest to surgeons, as it has the advantage of following the plane of surgical approach. This article describes the advantages of using direct sagittal sections for studying various diseases of the temporal bone. The CT sections were obtained with the aid of a new head holder added to our GE CT 9800 scanner. The direct sagittal projection was found to be extremely useful for evaluating diseases involving the vertical segment of the facial nerve canal, vestibular aqueduct, tegmen tympani, sigmoid sinus plate, sinodural angle, carotid canal, jugular fossa, external auditory canal, middle ear cavity, infra- and supralabyrinthine air cells, and temporomandibular joint.

Bleeding of sinusectomy for chronic sinusitis

It is well known that the amount of bleeding of sinusectomy for chronic sinusitis is relatively large and differs much from case to case. The amount of bleeding during sinusectomy under local anesthesia was evaluated in 140 cases (251sides). Our routine sinusectomy consists of CaldwellLuc operation, transantral ethmoidectomy and endonasal surgery. The various factors influencing the amount of bleeding were investigated and the causes and definition for excessive bleeding were determined.The averaged amount of the bleeding was 195g. The durations of sinusectomy, degrees of intranasal finding, pre-operative CT findings in regard to ventilation status, and morbid findings in the maxillary sinus were all related with statistical significance to the amount of bleeding. On the contrary, sex, height, body weight, blood pressure, the thickness of the anterior wall of the maxillary sinus and the area of the maxillary sinus in axial CT sections were not related to the amount of bleeding. The excessive bleeding was defined as the bleeding more than 400g on the basis of analysis of our operative records. The excessive bleeding was seen in 10% of all the cases. Causes for the excessive bleeding were determined retrospectively from the our operative records. Such surgical steps for the posterior aspect of the lateral nasal walls as ethmoidectomy and enlargement of the membranous portion were the common causes (37%) for the excessive bleeding.