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Dental radiology and oral pathology.

This article represents an overview of normal and pathological findings of the oral structures for the practicing radiologist. Some of the disease processes discussed are of dental etiology, whereas others are manifestations of systemic diseases. Normal tooth development is described followed by an overview of radiolucent, radiopaque, and mixed lucent-opaque lesions. In the radiolucent category, normal anatomical landmarks of the jaws include the mental foramen, manidbular canal, incisive canal and maxillary sinuses. Other lucencies that represent normal structures or variations include developing tooth buds and root apices, healing dental extraction sites, prominent submandibular fossae and nutrient canals. In the radiopaque category, normal anatomical landmarks of the jaws include the genial tubercle, mental ridge, external oblique ridge, walls of the submandibular canal, walls of the maxillary sinus, nasal septum, stylohyoid ligament, and zygomatic process. Other opacities that represent normal structures or variations include dental restoration material, dental endodontic material, retained roots, sialoliths, salivary duct calculi, calcified lymph nodes, recent extraction sites, hypercementosis, and foreign bodies. Pathological entities which present radiographically as lucencies, opacities, and mixed lucent-opaque areas include inflammatory lesions, cysts, fibro-osseous disease, benign neoplasms, malignant neoplasms, and lesions secondary to metabolic disorders.

Humans↗

Spinal markers: A new method for increasing accuracy in spinal navigation.

Spinal navigation opens up a completely new dimension in the planning and realization of neurosurgical and orthopedic procedures, and offers the possibility of simulating the operation preoperatively. There is currently only limited experience with spinal navigation, and despite the development of advanced software, intraoperative difficulties include identification of characteristic and reproducible anatomical landmarks, localization of these points in the surgical field, referencing, and intraoperative control. We report the use of a new kind of implantable fiducial marker in a case of a 58-year-old female patient with spondylolisthesis. Percutaneously applied spinal markers were used as prominent anatomical landmarks and permitted much easier intraoperative handling. In our opinion, in the hands of an experienced neurosurgeon or orthopedist, the additional preoperative time required for placement of such spinal markers is negligible.

Bone Nails↗

Evaluation of software for registration of contrast-enhanced brain MR images in patients with glioblastoma multiforme.

OBJECTIVE: We evaluated commercially available software that rapidly and automatically registers brain MR images on a clinical workstation, and we studied the accuracy of these registrations. SUBJECTS AND METHODS: Ten patients with a diagnosis of glioblastoma multiforme underwent contrast-enhanced inversion recovery prepared three-dimensional (3D) volumetric spoiled gradient-recalled acquisition in the steady state (SPGR) MR imaging (contiguous 1.5-mm slice thickness, 96-104 slices). After this imaging sequence, each patient was brought out of the head coil into a sitting position and then repositioned in the coil. The inversion recovery prepared 3D SPGR sequence was then repeated. A commercially available software program operating on a clinical workstation was used to automatically register the second inversion recovery prepared SPGR series to the first. The speed of registration was recorded. The accuracy of each registration was estimated by recording the coordinates of eight anatomic landmarks on the registered and reference series and by calculating the mean error among matching landmarks. RESULTS: In nine of 10 patients, the registration software produced a visually satisfactory registration. In one patient, a second registration was necessary to produce a satisfactory registration. The processing time for each iteration was 48.3 +/- 3.8 sec (mean +/- SD). The mean error in aligning matching anatomic landmarks ranged from 0.67 to 1.41 mm, with an overall mean of 1.18 mm. The largest error among matching landmarks was 2.3 mm. CONCLUSION: Commercially available registration software can automatically register 3D imaging volumes in less than 1 min. The mean error in registration was approximately equivalent to the dimensions of a single voxel.

Adult↗

2003 William J. Stickel Bronze Award. Radiographic anatomy of the talus.

Detailed radiographic anatomy of the entire talus bone has not been previously described in the literature. We used radiopaque wire markers to identify 17 articular and nonarticular anatomical landmarks of the talus. Standard radiographic views of the foot and ankle were obtained: lateral (foot and ankle); anteroposterior, mortise, medial oblique, and lateral oblique (ankle); and dorsoplantar, medial oblique, and lateral oblique (foot). The resultant two-dimensional images are correlated to the three-dimensional anatomical specimen, and normal radiographic anatomy is described. Additionally, useful radiographic views for each anatomical landmark are identified. Composite figures of each useful view are presented as a pictorial atlas.

Awards and Prizes↗

Effect of same-sided and cross-body load carriage on 3D back shape in young adults.

UNLABELLED: Regular carriage of heavy loads such as backpacks, satchels and mailbags results in a variety of acute medical problems and increased potential for back injury. There is a paucity of information about the specific changes in back posture that occur in response to asymmetrical loading. The purpose of this study was to examine the changes in back shape that occurred in response to asymmetrical load carriage, either on one shoulder (same-side) or across the body (cross-body), in healthy young adults. METHODS: A convenience sample of 21 physiotherapy students randomly performed three trials (unloaded, same-side loaded, cross-body loaded) in standing with a 15% body load. The Microscribe 3DX digitiser (Immersion Group Ltd) recorded the three dimensional coordinates of 15 Key anatomical landmarks on the back in the three conditions. RESULTS: A one-way ANOVA with repeated measures and post-hoc tests was implemented to highlight statistical differences in the data collected (p<0.05). Significant differences were found in the x, y and z coordinates of the anatomical landmarks in the upper back between unloaded and loaded conditions. Results demonstrated significantly less impact on spinal posture from cross-body loading as compared to same-sided loading. CONCLUSION: This study confirms that there are significant three-dimensional changes in back shape in response to asymmetrical loading. Further work is needed to evaluate the optimal carriage type and maximal body load that results in the least spinal impact and injury potential in young adults.

Adult↗

Reliability of conformational measurements in the horse using a three-dimensional motion analysis system.

REASONS FOR PERFORMING STUDY: The importance of a reliable method for conformation studies is generally acknowledged, but there are only limited data on the accuracy and precision of current assessment methods. OBJECTIVES: To assess (1) the accuracy and repeatability of marker placement, (2) influence of stance of the horse on conformational parameters, (3) practicality of a computerised motion analysis system and (4) to compare the computerised motion analysis system to photographic systems of assessment. METHODS: Twenty-eight reflective markers placed over anatomical landmarks were located in 3D using a computerised motion analysis system and their coordinates used to calculate segment lengths and joint angles. Four experiments, involving a cadaver study, a series of repeated measures on a single Thoroughbred and repeat measurements on 108 racehorses were performed. RESULTS: Identification of anatomical landmarks was found to introduce the biggest variation in the measurements for proximal conformation parameters with the interoperator being larger than intraoperator variation. Length measurements were least influenced by stance, with distal interphalangeal and metacarpo/metatarsophalangeal joint angles being the most variable. In some measurements, the variation between stances within a horse proved to be almost as large as between horses, rendering these parameters less useful as predictors of performance or orthopaedic health. CONCLUSIONS: A computerised motion analysis system allows 3D assessment of conformation with high accuracy and precision. It eliminates 3 major sources of error associated with photography-based methods and increases accuracy of conformational assessment by allowing repeat measurements in a relatively short period. POTENTIAL RELEVANCE: Studies on conformation should be viewed in the light of the limitations of the measurement technique used. The presented method maximises accuracy and precision and is a valuable basis for future studies investigating the effect of conformation on performance or orthopaedic health.

Animals↗

Lateral approach for arthrocentesis of the distal interphalangeal joint in horses.

OBJECTIVE: To determine anatomic landmarks for a lateral approach for arthrocentesis of the proximopalmarolateral aspect of the distal interphalangeal (DIP) joint in horses and the likelihood of entering synovial structures other than the DIP joint through this approach. DESIGN: Prospective study. SAMPLE POPULATION: Paired forelimbs of 8 cadavers and 12 horses. PROCEDURE: Anatomic preparations were used to determine anatomic landmarks. Positive-contrast arthrography was used to determine which structures were entered. RESULTS: Landmarks for the lateral approach included a depression in the proximal border of the lateral ungular cartilage and the palmar border of the middle phalanx. Use of the lateral approach for arthrography resulted in deposition of contrast material exclusively in the DIP joint in only 13 of 20 limbs, whereas use of the dorsal approach resulted in deposition of contrast material exclusively in the DIP joint in 20 of 20 limbs. CLINICAL IMPLICATIONS: The lateral approach is an alternative to the conventional dorsal approach to the DIP joint in horses, however, inadvertent entry into adjacent synovial structures is a possible complication. The lateral approach provides an additional portal for through-and-through lavage and arthroscopic access to the palmar aspect of the DIP joint.

Animals↗

Correspondence between functional magnetic resonance imaging somatotopy and individual brain anatomy of the central region: comparison with intraoperative stimulation in patients with brain tumors.

OBJECT: The goal of this study was to determine the somatotopical structure-function relationships of the primary motor cortex in individual patients by using functional magnetic resonance (fMR) imaging. This was done to assess whether there is a displacement of functional areas compared with anatomical landmarks in patients harboring brain tumors close to the central region, and to validate these findings with intraoperative cortical stimulation. METHODS: One hundred twenty hemispheres in 60 patients were studied by obtaining blood oxygen level-dependent fMR images in patients while they performed movements of the foot, hand, and face on both sides. There was a good correspondence between anatomical landmarks in the deep portion of the central sulcus on axial slices and the somatotopical organization of primary motor areas. Pixels activated during hand movements were centered on a small characteristic digitation; those activated during movements in the face and foot areas were located in the lower portion of the central sulcus (lateral to the hand area) and around the termination of the central sulcus, respectively. In diseased hemispheres, signal-intensity changes were still observed in the projection of the expected anatomical area. The fMR imaging data mapped intraoperative electrical stimulation in 92% of positive sites. CONCLUSIONS: There was a high correspondence between the somatotopical anatomy and function in the central sulcus, which was similar in normal and diseased hemispheres. The fMR imaging and electrical stimulation data were highly concordant. These findings may enable the neurosurgeon to locate primary motor areas more easily during surgery.

Adult↗

Ventriculostomy in a tumor involving the third ventricular floor.

Recently, endoscopic management has gotten preference over open surgical treatment in selected cases of intraventricular tumors. Endoscopic third ventriculostomy (ETV) appears unfeasible when tumors extend to the third ventricular floor region due to the risk of perforators and injury to the basilar artery. We report the case of a 12-year-old male with symptoms of acute, chronic, raised intracranial pressure. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a posterior third ventricular tumor involving the aqueductal and floor regions. The ETV was done after clearing the floor by partial tumor resection, keeping the dorsum sellae as the major anatomical landmark. The patient improved satisfactorily and was given adjuvant radiotherapy, and the need for an external shunt was completely eliminated. We conclude that ETV appears worth trying, even in third ventricular tumors involving the floor region if they can be cleared from the tumor keeping the dorsum sellae as the major anatomical landmark.

Cerebral Aqueduct↗

Image guided surgery for petrous apex lesions.

OBJECTIVES: To evaluate whether computer-assisted frameless stereotactic navigation in the temporal bone provides sufficient clinical application accuracy and thus a useful tool in temporal bone surgery. METHODS: Two patients with petrous apex cholesterol granuloma were operated on by an epidural middle fossa approach using a Stealth/Medtronic trade mark neuronavigation system. Based on literature data optimal skin fiducial placement and registration methods were used. Intra-operative accuracy was checked using three precise anatomical landmarks. Drilling of the petrous apex bone was guided by neuronavigation. Postoperative Computed Tomography (CT) images were fused with the preoperative CT and planning. RESULTS: The application of image-guidance in temporal bone surgery causes no additional burden to the patient nor prolongs the operating time. The accuracy measured at the anatomical landmarks was under 2,0 mm. This is confirmed by evaluation of bone removal through image fusion of pre- and postoperative CT-scan. CONCLUSIONS: The clinical application of a neuronavigation system during petrous apex surgery can be regarded as useful. Using all available data on registration methods it seems possible to obtain intra-operative application accuracies of <2,0 mm. Additional cadaver work is being performed to support these data.

Adult↗

Laparoscopic adrenalectomy: current status with a review of Japanese literature.

A decade has elapsed since laparoscopic adrenalectomy was first performed in 1992. Accumulated experiences of laparoscopic adrenalectomy have shown superior results to treat small functional benign tumors and make the indication expand to large tumors, pheochromocytomas and localized malignant tumors. Following the initially established transperitoneal approach, which includes anterior and lateral approaches, the retroperitoneal lateral flank and posterior lumber approaches have been performed. Each approach has advantages and disadvantages. The transperitoneal approach supplies a large operative field, many anatomical landmarks and easy handling. But it causes post-operative irritability and it is very difficult to perform after previous upper abdominal surgery. The retroperitoneal approach can be performed even after previous abdominal surgery and patients may be more comfortable after the operation. However, the narrow working space and the lack of anatomical landmarks may increase the rate of intra-operative complications and the rate of conversion to open surgery. Although there is no clear preference between transperitoneal and retroperitoneal approaches, the transperitoneal approach is commonly employed and the transperitoneal anterior approach seems to be the easiest one for right adrenal tumors and the transperitoneal lateral approach for left adrenal tumors. The shorter convalescence with laparoscopic adrenalectomy as compared with open adrenalectomy has been accepted and lower morbidity from laparoscopic adrenalectomy has been achieved. The operative time has been shortened to the level of open adrenalectomy. Less blood loss, less pain and better cosmesis are absolute advantages for the patients. Laparoscopic adrenalectomy is now the gold standard for the treatment of adrenal tumors.

Adrenalectomy↗

Measurement of acetabular component migration using two-dimensional radiography.

The relationships between apparent acetabular component migration, choice of anatomic landmarks, and changes in rotation of the pelvis were determined by examining radiographs of a pelvic model in multiple projections. The minimum apparent migration associated with transverse and longitudinal rotation of 5 degrees from neutral was 2 mm. The least apparent migration was noted when the teardrop was used as the principal anatomic landmark. Determination of component migration in clinical studies from serial radiographs involves a minimum projection and magnification error of 2 mm.

Acetabulum↗

Accuracy of blind versus fluoroscopically guided caudal epidural injection.

STUDY DESIGN: A prospective observational study of a case series of patients with low back pain referred for epidural injection of corticosteroid. OBJECTIVES: To evaluate the accuracy of caudal epidural injections performed without the use of fluoroscopic guidance and to determine the value of specific clinical tests performed during the procedure in predicting successful epidural needle placement. SUMMARY OF BACKGROUND DATA: Epidural injection of corticosteroid is one of many treatments currently used in the nonsurgical management of low back pain. The face validity of many studies evaluating the efficacy of epidural corticosteroid injections has been criticized for use of a blind technique. Although there currently is no consensus in the spine literature as to whether epidural injection of corticosteroid (by any technique) is effective, it is imperative first to establish the accuracy of the technique being used. METHODS: A total of 54 consecutive patients underwent fluoroscopically guided caudal epidural injections. Needle insertion was performed blindly (without the use of fluoroscopic guidance), and the success of needle placement was predicted according to the presence of palpable landmarks, palpation of subcutaneous airflow, and the subjective impression that the needle was in a satisfactory position. These clinical criteria then were compared with the position of the needle as seen under fluoroscopy and the spread of radio-opaque contrast in the epidural space after the procedure. RESULTS: Successful injection placement on the first attempt occurred in 74.1% of the patients. Results were improved when anatomic landmarks were identified easily (87.5%) and no air was palpable subcutaneously over the sacrum when injected through the needle (82.9%). The combination of these two signs predicted a successful injection in 91.3% of attempts. CONCLUSIONS: Caudal epidural injection is performed ideally with fluoroscopic guidance as the gold standard for accurate drug placement. If fluoroscopic guidance is unavailable, impractical, or contraindicated, the presence of readily palpable anatomic landmarks at the sacral hiatus and the absence of palpable subcutaneous airflow over the sacrum significantly increase the operator's confidence in the likelihood of an accurate injection even before any products are administered into the epidural space.

Adult↗

Clinical and anatomy study of the human mental foramen.

The great diffusion of the surgical techniques in jaws surgery and the progress of the radiological imagining procedures expressed many interest in clinical anatomy of the mental foramen (MF). The study goal was to determine the precise location of the MF and the surrounding anatomical landmarks. Measurements of the MF position relative to the surgical landmarks and related posterior teeth were made on 20 dry mandibles with complete dentition and intact alveolar bridge obtained from the Institute of Anatomy, School of Medicine, University in Sarajevo. The measurements were made by anthropometric methods on the booth sides of the mandible, and compared with measurement made on the orthopantomogram radiographs of the same mandibles. The most common position of the MF was in line with the longitudinal axis of the second premolar. In the vertical plane on the skulls the MF lays in the midpoint of the distance between the lower border of the mandible and the alveolar margin, however on the orthopantomogram MF appeared slightly bellow the midpoint. In the horizontal plane it lays approximately one third of the distance between the mandibular symphysis and the posterior border of the ramus of the mandible measurement from A-P projection and one quarter of that distance measurement from the profile projection. There were no significant differences between distances MF from posterior border of the ramus of the mandible measurement from A-P and profile projection and the one obtained on orthopantomogram and their ratio is constant value determine das 1,065. The MF was on average 25 mm lateral to the mandibular skeletal midline and symmetrical, and symmetry was preserved on the orthopantomogram. The measurement showed significant differences in distances of M from superior border mandible measurement on dry mandible and orthopantomogram radiographs while distance bellow the MF was not significantly different. The constant values of MF distance to the posterior border of the ramus of the mandible measured as 1,065 and the distance to the medial skeletal line of 2,11 made it possible to also determine average angle of 43 degrees stream of the cor-pus of the mandible behind MF. These values in combination with ratios of MF to the different anatomic landmarks designated as relative horizontal and relative vertical position, would be of importance not only from anatomical but also from practical point of view for estimation of alveolar bridge resorption and preoperative analysis in orthognat postresection or implant surgery in the mandible.

Chin↗

Appearance, location, course, and morphology of the mandibular incisive canal: an assessment on spiral CT scan.

OBJECTIVES: To assess the appearance, location, and course of the incisive canal as compared to other anatomical landmarks on spiral CT of the mandible. METHODS: Study material included 230 spiral CT scans taken for preoperative planning of implant placement in the posterior mandible. All scanning was performed using a standard exposure and patient positioning protocol. Axial, panoramic, and reformatted cross-sectional images were carefully examined. Visibility of the incisive canal and other anatomical landmarks was scored using a four-point rating scale. The vertical and buccolingual diameter of the outer contour as well the diameter of the inner contour of the incisive canal were measured using a digital sliding caliper. RESULTS: An incisive canal was identified in 93% of the cases, with good visibility in 22% of the cases. Mean (s.d.) vertical diameter, buccolingual diameter, and inner diameter of the incisive canal were 4.7 (1.1), 3.7 (0.7), and 1.1 (0.3) mm respectively. The mandibular canal, mental foramen, lingual foramen, and anterior looping appeared in 98, 100, 82 and 7% of the images respectively. CONCLUSIONS: A well-defined incisive canal could be detected in the majority of spiral CT scans. Its radiographic detection remained lower than for the mandibular canal or mental foramen, but higher than for the visibility of the lingual foramen. Visualisation of the incisive canal and the occasional presence of an anterior looping, demonstrates the potential value of cross-sectional imaging of the anterior mandible for presurgical planning purposes.

Adolescent↗

Application of a stereoradiographic method for the study of intervertebral motion.

A technique of three-dimensional reconstruction along with a method of adjusting anatomic landmarks were used to evaluate movements of the lumbar vertebrae of living subjects. Altogether, 16 subjects took part in the experiment. Each subject was radiographed in an upright standing position, and in each of the following positions: flexion, extension, axial rotation, and lateral bending. The results of the three-dimensional reconstruction procedures and the correction of anatomic landmarks show an adequate level of accuracy for experimentation with living subjects. The mean relative displacements of lumbar vertebrae in rotation are 10 degrees of flexion, 3 degrees of extension, 5 degrees of lateral bending, and 1 degree of axial rotation.

Adult↗

Physician training requirements in sonography: how many cases are needed for competence?

OBJECTIVE: Physician competence in the performance of sonographic studies was assessed after their involvement in predetermined increments of cases to determine whether the case volumes currently required by the American Institute of Ultrasound in Medicine and the American College of Radiology for training in sonography can be lowered substantially. MATERIALS AND METHODS: Sonographic competence tests were administered to 10 first-year diagnostic radiology residents after their involvement in increments of 50 cases, up to a total of 200 cases (four competency tests). Each competency test consisted of the resident's independently scanning and interpreting 10 clinically mandated studies that were scored in comparison with the examination performed by the sonographer and interpreted by an attending radiologist. Trainee studies were graded on the percentage of anatomic landmarks depicted, the number of reporting errors, the number of clinically significant reporting errors, and the percentage of cases receiving a passing score. RESULTS: Although resident performance improved progressively with increasing experience for all parameters assessed, performance of the group was poor even after their involvement in 200 cases. At this testing level, the mean percentage of anatomic landmarks depicted successfully was 56.5%; the mean total reporting errors per case was 1.2; the mean clinically significant errors per case was 0.5; and the mean percentage of cases receiving a passing score was 16%. Impressive performance differences were observed among residents for all parameters assessed, and these differences were not explained by the number of months of radiology training the resident had taken before the sonography rotation. CONCLUSION: Involvement in 200 or fewer cases during the training period is not sufficient for physicians to develop an acceptable level of competence in sonography.

Clinical Competence↗

Pinhole SPECT imaging in normal and morbid ankles.

UNLABELLED: Pinhole SPECT can generate sectional nuclear images of a normal and morbid ankle and hindfoot with remarkably enhanced resolution by portraying the topography and pathological alterations in great detail. METHODS: Pinhole SPECT was performed using a commercially available single-head, rotating gamma camera system by replacing the parallel-hole collimator used for planar SPECT with a pinhole collimator. The images were reconstructed in the same way as in planar SPECT by using the filtered back-projection algorithm and a Butterworth filter. First, we compared the scan resolution between the planar and pinhole SPECT images of a thyroid phantom and a normal ankle and hindfoot by working out pinhole SPECT anatomy with CT validation. Second, the clinical usefulness was assessed in one case each of fracture, reflex sympathetic dystrophy syndrome and rheumatoid arthritis of the ankle with radiographic correlation. The resolution of the pinhole SPECT and planar pinhole images was compared for these diseases. RESULTS: The resolution of the pinhole SPECT of a thyroid phantom and of a normal ankle and hindfoot was significantly enhanced compared to the planar SPECT although image distortion was seen in the periphery of the field-of-view. The pinhole SPECT resolution was such that most of the anatomical landmarks were sharply delineated in the ankle and hindfoot and some useful diagnostic signs in the diseased ankle were visible. CONCLUSION: Pinhole SPECT can be performed using a single-head gamma camera system and filtered back-projection algorithm. It generates sectional scan images of both normal and morbid ankle and hindfoot with enhanced resolution portraying many anatomical landmarks and pathological signs in useful detail.

Adult↗