Please, no more deaths from neglect

BACKGROUND: High resolution computed tomography (HRCT) is highly efficient in demonstrating the anatomy of the temporal bone. This study evaluates its application to temporal bone fractures (TBF). METHODS: We collected data from 26 cases of TBF in the past two years. All cases underwent HRCT examination. The clinical information was reviewed and correlated with the imaging findings. RESULTS: Eighty-six percent of the cases had longitudinal fractures. Axial scans were the most useful in identifying the fracture line. Mastoid opacification on routine head computed tomography (CT) was also useful in indicating possible TBFs. Complications of TBF, such as ossicular chain disruption, facial nerve damage or otorhino-liquorrhea, were identified clearly using HRCT. CONCLUSIONS: To minimize or prevent the sequelae of TBF, accurate radiologic evaluation is necessary as soon as possible after injury. HRCT of the temporal bone delineates the bony and soft tissue anatomy with high accuracy and we recommend it as the diagnostic modality of choice.     

Clinical and surgical application of reformatted high-resolution CT of the temporal bone

High resolution CT has played a pivotal role in temporal bone imaging since the early 1980s. Although the appearance of MR imaging technology with its superior demonstration of fluid-containing spaces of the inner ear and the posterior fossa structures, CT continues to offer distinct advantages for the evaluation of conductive hearing loss, and petrous apex lesions. With the advent of helical scanning techniques, CT is increasingly the imaging study of choice for definitive preoperative temporal bone imaging.     

CT evaluation of congenital aural atresia: what the radiologist and surgeon need to know

PURPOSE: The preoperative evaluation of aural atresia and stenosis is strongly dependent upon high resolution CT. We have devised a 10 point surgical rating scale based on high resolution CT of the temporal bone that will provide radiologists with a stepwise method of evaluating these scans and will allow them to communicate these findings to otologic surgeons in a consistent fashion. METHOD: We prospectively evaluated 1,500 patients with aural atresia or stenosis for eight critical areas of temporal bone anatomy, each area receiving 1 rating scale point, with the exception of the presence of a stapes, which received 2 points. The appearance of the external ear received the final point on the rating scale since the external ear is formed earlier than the middle ear and helps to predict its deformities. The presurgical score was utilized in selecting surgical candidates and was correlated with the intraoperative findings as well as the postsurgical results by comparing pre- and postoperative speech reception threshold. Patients with a presurgical rating of < or = 5 were not considered surgical candidates. Otherwise, the percentage of successful surgeries corresponded roughly to the rating scale. RESULTS AND CONCLUSION: Thus, a presurgical rating of 8 points translates into an 80% chance of restoring hearing to normal or near-normal levels.     

Diagnostic imaging in otorhinolaryngology--assessment of current status

BACKGROUND: The first conventional x-rays of the paranasal sinuses were received in 1897, just two years after the detection of x-rays. During the following decades several modifications and extensions of conventional radiologic techniques were developed, but routine imaging procedures of the head and neck were mainly restricted to pictures of the paranasal sinuses and the temporal bone. In the fifties, tomography was developed, which gave us a more detailed insight of the anatomy and pathology of the paranasal sinuses and temporal bone. During the last two decades the development of new techniques, i.e. computed tomography (CT) and magnetic resonance imaging (MRI), has significantly increased the importance of modern imaging for the diagnostic evaluation of head and neck diseases. These diagnostic tools enable us to visualize anatomical structures and pathological entities with an accuracy never been expected beforehand. The pace of the improvement of these diagnostic tools, however, requires that both radiologist and otorhinolaryngologist keep up with the adequate indications of CT and MRI in the different areas of the head and neck. A close relationship and cooperation between radiologist and ENT surgeon is therefore indispensible for a fruitful and cost-effective use of modern imaging. Otherwise the patient is exposed to modern medical technology without an equivalent benefit. The purpose of the present paper is mainly to give an update and state of the art of modern imaging techniques in otorhinolaryngology, head and neck surgery. Different areas i.e. paranasal sinuses, temporal bone, salivary glands, oral cavity and oropharynx as well as the neck are discussed in terms of adequate indications for modern imaging in the diagnostic evaluation of different lesions.     

Human pancreatic proenzymes are activated at different rates in vitro

The measurement of regional bone mineral density (rBMD) is a new method of evaluation of the human temporal bone in vitro or in vivo. Modified computed tomography (CT) enables us to collect a three-dimensional array of precise, reproducible bone density values, as well as high-quality CT images. Measurements are calibrated using phantoms of known composition and density. Conventional CT provides density information that is relative, qualitative, and lacks precise reproducibility over time. The rBMD technique provides precise numeric density measurements. Additional image processing capabilities are described. In vivo data from six normal temporal bones and from two patients with Paget's disease involving the temporal bone are presented to demonstrate the technique.     

Functional MRI lateralization of memory in temporal lobe epilepsy

OBJECTIVE: To determine the feasibility of using functional magnetic resonance imaging (fMRI) to detect asymmetries in the lateralization of memory activation in patients with temporal lobe epilepsy (TLE). BACKGROUND: Assessment of mesial temporal lobe function is a critical aspect of the preoperative evaluation for epilepsy surgery, both for predicting postoperative memory deficits and for seizure lateralization. fMRI offers several potential advantages over the current gold standard, intracarotid amobarbital testing (IAT). fMRI has already been successfully applied to language lateralization in TLE. METHODS: fMRI was carried out in eight normal subjects and 10 consecutively recruited patients with TLE undergoing preoperative evaluation for epilepsy surgery. A complex visual scene encoding task known to activate mesial temporal structures was used during fMRI. Asymmetry ratios for mesial temporal activation were calculated, using regions of interest defined in normals. Patient findings were compared with the results of IAT performed as part of routine clinical evaluation. RESULTS: Task activation was nearly symmetric in normal subjects, whereas in patients with TLE, significant asymmetries were observed. In all nine patients in whom the IAT result was interpretable, memory asymmetry by fMRI concurred with the findings of IAT including two patients with paradoxical IAT memory lateralization ipsilateral to seizure focus. CONCLUSIONS: fMRI can be used to detect asymmetries in memory activation in patients with TLE. Because fMRI studies are noninvasive and provide excellent spatial resolution for functional activation, these preliminary results suggest a promising role for fMRI in improving the preoperative evaluation for epilepsy surgery.     

Comparison of LC detection methods in the investigation of non-UV detectable organic impurities in a drug substance

The cartilaginous structures in the growing ends of the bone have a complex anatomy. MR imaging allows exquisite depiction of these structures. The normal anatomy and biochemical features of the zones of cartilage are reviewed. Based on an analysis of signal characteristics, it is possible to optimize the use of pulse sequences to study the normal structures and abnormalities of growing bone.     

Squamous cell lung carcinomas: the role of nm23-H1 gene

The position of the jugular bulb varies greatly. A high jugular bulb procident from the temporal bone is not uncommon. Most people with this anatomic variation remain asymptomatic. We report seven cases of high jugular bulb with clinical manifestations. The anatomy, clinical manifestations, diagnosis, and management are reviewed.     

Normal sternal bone marrow MRI using STIR

The MR signal of sternal bone marrow was examined in 21 normal volunteers using a sagittal STIR sequence. Craniocaudal phase-encoding with a hand-made positioning device effectively eliminated artifacts due to cardiac pulsation. The sternal bone marrow signal could be classified into three patterns based on the signal distribution. The superior segment of the manubrium showed characteristic age-related changes. This method provided high spatial resolution and excellent bone marrow imaging. Knowledge of a normal marrow signal pattern may be useful for the evaluation of hematological disorders.     

Advanced MR imaging techniques for evaluation of the heart and great vessels

A "one-stop shop" for evaluating cardiac disease with magnetic resonance (MR) imaging is progressing toward clinical reality and promises to have a major effect on the care of patients with cardiac disease. T1-weighted conventional spin-echo imaging gated to the cardiac cycle yields good anatomic detail but requires long imaging times and provides only static images of a single cardiac phase. Fast MR imaging with electrocardiographically (ECG) gated, low-flip-angle, segmented k-space gradient-recalled-echo (GRE) sequences provides excellent image quality with sufficiently high temporal resolution to "freeze" cardiac motion. Segmented k-space sequences improve on standard ECG-gated GRE sequences by allowing many cardiac phases, or frames of a cine sequence, to be imaged in a single breath hold with prospective cardiac gating. As commercial implementations of segmented k-space imaging become more widely available, the applications of this technique are expanding from research protocols to include many clinical applications in the heart and great vessels. Such applications include evaluation of vascular anatomy (coronary angiography, aortic disease, aberrant vessels, vascular access), cardiac anatomy (congenital anomalies, right ventricular dysplasia, constrictive pericarditis, valvular function), myocardial perfusion, and myocardial wall motion.     

Occipital condyle fracture and ligament injury: imaging by CT

The true incidence of fracture of the occipital condyles is unknown. It may be associated with instability at the craniocervical joint. CT is the modality of choice for the demonstration of these fractures, but its use for imaging of the associated ligament injury has not been reported. In order to demonstrate normal anatomy, occipital condyle fracture and ligament injury, and to estimate the incidence of this lesion, 21 children and young adults with high-energy blunt craniocervical injury were examined prospectively. Thin-slice, axial, contiguous, CT was performed from the base of C2 to above the foramen magnum. Bone and soft tissue windows and coronal, sagittal, and curvilinear 2D reconstructions were performed. Five occipital condyle fractures were identified in four patients (19 %), with demonstration of alar ligament injury in two cases and local hematoma in one. In four, artifacts or rotation precluded assessment of ligaments. In all remaining cases normal bone and ligament anatomy was demonstrated. Fracture of the occipital condyles following craniocervical injury is not uncommon in children and young adults. Normal bone and ligament anatomy and pathology can be safely and clearly demonstrated in seriously injured patients and others using this CT technique. Increased awareness of this entity and a low threshold for performing CT should avoid the potentially serious consequences of a missed diagnosis.     

A transmission/disequilibrium study of the DRB1*04 gene locus on chromosome 6p21.3 with schizophrenia

The precise relationship of the components of the heart can be difficult to understand. With recent developments in cardiac ultrasound and other imaging modalities, most professionals need to be familiar with cross-sectional cardiac anatomy. We have created a teaching technique based on a normal human heart removed at autopsy. It was scanned using a computed tomography scanner and the images examined in different planes. The images were annotated and used in a computer-based teaching program to convey the details of cardiac anatomy. Images corresponding to planes typically used in echocardiography were also examined. The resulting images were of high resolution and illustrated many subtle structures rarely seen in conventional studies of cardiac anatomy. This system has benefits to both clinicians and anatomists.     

The regeneration of soft tissue and bone around implants with and without membranes

The popularity of osseointegration for the replacement of anterior teeth has placed an increased demand on the preservation of normal gingival anatomy. This has led to the development of a variety of soft-tissue and bone-augmentation techniques that either prevent tissue collapse or restore previously damaged areas of the alveolus. With bone grafts, barrier membranes, and autogenous connective-tissue grafts used in combination with each other or separately, lost structures can be reconstructed into a normal configuration for optimum esthetic restorations.     

Computer-stimulated test fitting of an implantable hearing aid using implantable hearing aid using three-dimensional CT scans of the temporal bone: preliminary study

In preparation for future implantation of the implantable middle ear transducer in patients, a method was sought for preoperatively test fitting a model of the device, using computer generated three-dimensional (3-D) temporal bone images derived from spiral computed tomography (CT) data. A 3-D model of the implantable middle ear transducer was designed using NIH Image software on a Macintosh computer. High resolution human temporal bone CT scans were obtained using a spiral CT scanner (Siemens Somatom Plus S). The 3-D transducer model was superimposed onto 3-D reconstructions of the temporal bone using ANALYZE software on a computer graphics workstation (Sun SPARCstation 10), showing the transducer "implanted" in the temporal bone. Measurements were validated using a cadaver temporal bone. This process produced images demonstrating the "fit" of the current transducer design in the mastoid region of the adult temporal bone. It permitted assessment of the proximity of surrounding structures such as the external auditory meatus, dura, or sigmoid sinus. Preliminary cadaver validation measurements confirmed the accuracy of this method. Three-dimensional CT is a feasible method for preoperative planning of the surgical implantation of devices in the temporal bone. This method of 3-D test fitting will be used in the future to determine optimum orientation and size limitations for human implantable devices.     

The high jugular bulb: report of five cases and a review of the literature

The jugular bulb varies widely in position and dimensions. A high jugular bulb is not an uncommon finding in temporal bones. Besides our five cases with different clinical manifestations, we review 52 cases diagnosed clinically and published previously in the English literature. The high jugular bulb occurs more often on the right temporal bone. Certain pathologic conditions, such as an abnormal bone formation, an aberrant sinusojugular system, or decreased pneumatization of the mastoid bone, may predispose an individual to its occurrence. Most people with this anatomical variation remain asymptomatic. However, various otologic problems and symptoms may be attributed to this condition. A high resolution computed tomography scan is the most convenient diagnostic tool at present. Law projection plain mastoid radiography may reveal a high jugular bulb in certain cases, providing a preoperative warning to an otologic surgeon. An exploratory tympanotomy is not suggested for those with a high jugular bulb with a conductive hearing loss, while jugular vein ligation has been reported to have good results in alleviating intractable pulsatile tinnitus. For most asymptomatic patients, regular long-term follow-up is recommended.     

Petrous apex arachnoid cyst: radiographic confusion with primary cholesteatoma

The advent of combined computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of petrous apex lesions has improved the otologist's ability to differentiate among many disease processes. Temporal bone CT details osseous anatomy, whereas MRI delineates soft tissue signal characteristics. The employment of these two imaging modalities is often successful in differentiating between cholesterol common entities encountered in the petrous apex. The finding of a smoothly marginated, expansile, bone eroding lesion on CT, coupled with hypointensity on T1-weighted and hyperintensity on T2-weighted images on MRI, is highly suggestive of cholesteatoma. The authors recently encountered two cases of arachnoid cyst involving the petrous apex that shared the same imaging features seen with the more common cholesteatoma. One patient presented with tic douloureux, whereas the other had a spontaneous transotic cerebrospinal fluid leak. The contemporary skull base surgeon should include arachnoid cyst as a rare possibility in the evaluation and treatment of petrous apex lesions.     

Global phylogeography of the ridley sea turtles (Lepidochelys spp.) as inferred from mitochondrial DNA sequences

BACKGROUND: The cardiovascular applications of magnetic resonance (MR) techniques in coronary artery disease have increased considerably in recent years. Technical advantages of MR imaging are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. These characteristics allow the accurate assessment of left ventricular mass and volume, the differentiation of infarcted from normal tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. METHODS: In addition to the conventionally used spin-echo and cine-echo techniques, newer techniques such as myocardial tagging, ultrafast MR imaging and MR coronary angiography have been developed. These newer techniques allow a more accurate assessment of ventricular function (tagging), myocardial perfusion (ultrafast imaging), and evaluation of stenosis severity (MR coronary angiography). Particularly early detection and flow assessment of stenosed coronary arteries and bypasses by MR angiography would constitute a major breakthrough in cardiovascular MR imaging. Apart from the MR imaging techniques, cardiac metabolism may be well assessed using MR spectroscopy. This provides unique information on the metabolic behaviour of the myocardium under conditions stress-induced ischemia. However, the definite niche of cardiac MR spectroscopy has still to be settled. CONCLUSION: Currently, MR techniques allow the evaluation of anatomy and function (accepted use), perfusion and viability (development phase), and coronary angiography (experimental phase). A particular strength of MR imaging is that one single MR test may encompass cardiac anatomy, perfusion, function, metabolism and coronary angiography. The replacement of multiple diagnostic tests with one MR test may have major effects on cardiovascular healthcare economics and would outweight the cost inherent to the MR angiography procedure.     

Concurrent and predictive validity of an early language screening program

MR imaging has fulfilled many of the dreams of the pediatric radiologist studying the hip: it has allowed depiction of detailed anatomy, evaluation of vascularity and perfusion, determination of synovial proliferation activity in chronic arthritis, and detection of bone marrow changes with great sensitivity. MR imaging also has brought some disenchantments; it lacks specificity, it is expensive and long, and it often requires sedation. MR imaging is operator dependent and hardware and software dependent. Finally, issues of cost-effectiveness and clinical efficacy in comparison with good physical examination and conventional radiography or ultrasound remain unresolved. Demonstration of its cost-effectiveness in the clinical setting is clearly the dominant challenge facing MR imaging today.     

Further characterization of the DFNA1 audiovestibular phenotype

BACKGROUND: Autosomal dominant, nonsyndromic, hereditary hearing impairment in a large Costa Rican kindred is caused by a mutation in the human homolog of the Drosophila diaphanous gene. OBJECTIVE: To further characterize the phenotype of DFNA1 with comprehensive audiovestibular evaluation and computed tomography of the temporal bone. PATIENTS: One affected child and 2 affected adults of the Costa Rican kindred who harbor a mutation in the diaphanous gene. SETTING: Medical Center at the University of California, San Francisco. INTERVENTION: Otologic and neuro-otologic examination; pure tone audiometry, speech audiometry, and immitance testing; auditory evoked potentials, electrocochleography, and otoacoustic emissions; electronystagmography and vestibular autorotation tests; and computed tomography of the temporal bone. RESULTS: The youngest subject, an 8-year-old boy, had a mild hearing loss, intact stapedial reflexes, otoacoustic emissions at high frequencies, normal auditory evoked potentials, and electrocochleographic findings consistent with endolymphatic hydrops. The two adults had severe to profound bilateral sensorineural hearing impairment. Electronystagmography disclosed normal vestibular function. Computed tomography demonstrated normal external, middle, and inner ear structures. CONCLUSIONS: These results suggest that the early low-frequency hearing loss in this family is associated with endolymphatic hydrops. Elucidation of the role of the diaphanous gene in hearing will therefore lead to a better understanding of the mechanism of endolymphatic hydrops.     

Ligaments of the ankle: normal anatomy with MR arthrography

PURPOSE: Our purpose was to define the normal MR arthrographic anatomy of ankle ligaments. METHOD: Prior to injection of intraarticular gadolinium in cadaveric ankle joints, proton density and T2-weighted images were obtained to assess the integrity of the ligaments and tendons as well as the amount of preexisting joint effusion. Following injection of 10 ml of contrast agent (gadopentetate dimeglumine 1:250, Omnipaqe 300, Knox gelatin 50%, and methylene blue), T1-weighted images with fat saturation in axial, oblique axial, coronal, and sagittal planes were obtained in neutral, dorsiflexion, and plantar flexion positions. Specimens were sectioned, allowing anatomic and MR correlation. RESULTS: Contrast agent outlining anterior and posterior aspects of the anterior talofibular ligament and posterior talofibular ligament (PTAF) was a normal finding, related to anterior and posterior recesses of the ankle joint that extend out beyond these ligaments in an anteroposterior direction above the level of the ligaments. Intraarticular contrast material allowed resolution of superficial and deep components of the posterior tibiofibular ligament. Both were seen separately from PTAF with dorsiflexion. Posterior intermalleolar ligament was not present in our specimens. Visualization of calcaneofibular ligament was much improved by contrast material outlining the articular aspect of the ligament. Visualization of the syndesmotic ligamentous complex also was improved by contrast material outlining the articular side of the ligaments and separating them from adjacent bone. Superiorly, the distribution of contrast agent was limited by the interosseous ligament. Visualization of the medial collateral ligaments was not improved by the presence of the intraarticular contrast material. CONCLUSION: MR arthrography of the ankle allows improved visualization and evaluation of the lateral and syndesmotic ligamentous complex.