Biomedical subjects
Publications and source records attributed to S James Zinreich.
For the theoretic advantages of 3T units to translate to improved diagnostic quality, careful attention must be paid to optimization of pulse sequences and development of clinically feasible imaging protocols. RARE sequences continue to be the choice for routine clinical imaging of the head and neck; although exquisite T2W images are afforded, T1W imaging is problematic. Short ETLT1W RARE imaging seems to be a good compromise.
Radiologic imaging is an essential part of the presurgical evaluation of patients with sinusitis and of the monitoring of difficult-to-treat,recurrent, and postsurgical disease. In patients with noninflammatory sinus pathology and those who "baffle" clinical diagnosis, ima-ging is extremely helpful in differentiating the various pathological entities and determining the extent of disease. Computerized tomography (CT), when deemed clinically necessary, is the current modality of choice to evaluate sinusitis. CT's ability to display bone,mucosa, and air makes it a perfect tool for imaging of the paranasal sinuses. The fine bony architecture of the nasal cavity and the para-nasal sinus drainage pathways are depicted accurately with CT examination.
Imaging of sinonasal structures has evolved from standard radiographs to the much more complicated and informative techniques used today. The plain radiograph was useful when the surgical techniques practiced were primarily aimed at the maxillary and frontal sinuses. With a better understanding of the mucociliary clearance of the nasal cavity and the paranasal sinuses, the surgical technique was shifted to the ethmoid sinuses and became more focal, thus needing a better understanding and display of the intricate morphology of the nasal cavity and paranasal sinuses. Polytomography was a step above plain radiographs and was first used in the display of the regional anatomy for the development of functional endoscopic sinus surgery. Polytomography was quickly replaced by computed tomography, as this imaging technique provides a much more detailed view of the sinonasal architecture than does polytomography. Magnetic resonance imaging has also shown usefulness in imaging this morphological area, as it provides better soft tissue resolution, but it does not allow good visualization of bony structures. Newer computer systems with software capable of reconstructing the digitized information into a 3-dimensional display further enhance our understanding of the regional morphology and afford an improved means of correlating the imaging and endoscopic information. Furthermore, stereotactic navigation systems allow surgeons the ability to visualize the endoscope-instrument tip position, as instruments are actively being used during surgery, on the computed tomographic and/or magnetic resonance images. There is a persistent trend toward reducing the size of the imaging equipment to render it more mobile (computed tomography) and adapt it for operating room use.
Magnetic Resonance Imaging (MRI) has unmatched potential for planning, guiding, monitoring and controlling interventions. MR arthrography (MRA) is the imaging gold standard to assess small ligament and fibrocartilage injury in joints. In contemporary practice, MRA consists of two consecutive sessions: 1) an interventional session where a needle is driven to the joint space and gadolinium contrast is injected under fluoroscopy or CT guidance. 2) A diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space and evaluate the condition of the joint. Our approach to MRA is to eliminate the separate radiologically guided needle insertion and contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners. We propose a 2D augmented reality image overlay device to guide needle insertion procedures. This approach makes diagnostic high-field magnets available for interventions without a complex and expensive engineering entourage.
Significant changes in surgical technique, surgical instrumentation, and imaging technology have occurred during the past 20 years. These changes have largely resulted from a better understanding of the pathophysiology ofa specific pathologic process, the inflammation of paranasal sinus mucosa. As surgical techniques were adapted to address clinical issues, new instrumentation was developed. Changes in imaging technology were also a result of these and similar issues pressing from other similar medical/surgical fields. The obsolescence of plain-film imaging is being addressed by miniaturization of large and bulky cross-sectional imaging equipment that will gradually become available and embraced by the clinical practice. These changes will bring about greater responsibilities, the foremost of which is vigilance in reducing radiation dose to the patient.
We present an image overlay system to aid needle insertion procedures in computed tomography (CT) scanners. The device consists of a display and a semitransparent mirror that is mounted on the gantry. Looking at the patient through the mirror, the CT image appears to be floating inside the patient with correct size and position, thereby providing the physician with two-dimensional (2-D) "X-ray vision" to guide needle insertions. The physician inserts the needle following the optimal path identified in the CT image rendered on the display and, thus, reflected in the mirror. The system promises to reduce X-ray dose, patient discomfort, and procedure time by significantly reducing faulty insertion attempts. It may also increase needle placement accuracy. We report the design and implementation of the image overlay system followed by the results of phantom and cadaver experiments in several clinical applications.
OBJECTIVE: We present a 2D image overlay device to assist needle placement on computed tomography (CT) scanners. MATERIALS AND METHODS: The system consists of a flat display and a semitransparent mirror mounted on the gantry. When the physician looks at the patient through the mirror, the CT image appears to be floating inside the body with correct size and position as if the physician had 2D 'X-ray vision'. The physician draws the optimal path on the CT image. The composite image is rendered on the display and thus reflected in the mirror. The reflected image is used to guide the physician in the procedure. In this article, we describe the design and various embodiments of the 2D image overlay system, followed by the results of phantom and cadaver experiments in multiple clinical applications. RESULTS: Multiple skeletal targets were successfully accessed with one insertion attempt. Generally, successful access was recorded on liver targets when a clear path opened, but the number of attempts and accuracy showed variability because of occasional lack of access. Soft tissue deformation further reduced the accuracy and consistency in comparison to skeletal targets. CONCLUSION: The system demonstrated strong potential for reducing faulty needle insertion attempts, thereby reducing X-ray dose and patient discomfort.
We present the case of a 30-year-old man with silent sinus syndrome. A CT scan obtained 10 years earlier showed completely normal maxillary sinuses. This case illustrates the acquired nature of this disorder.
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Although clinical judgment is sufficient to diagnose rhinosinusitis in many cases, a number of patients with recurrent or complicated sinus disease require imaging studies. Advances in the field of diagnostic imaging techniques such as computed x-ray tomography (CT) and magnetic resonance imaging have enhanced our understanding and management of the disease. Magnetic resonance imaging excels in displaying soft tissue resolution and is superior in demonstrating the presence of neoplasia and fungal sinusitis. but has limited advantages over CT scanning in demonstrating the regional anatomy (bony structure) and in the diagnosis of chronic rhinosinusitis. Computed tomography provides greater detailed information about the paranasal sinuses than do plain radiographic films. Rhinosinusitis staging systems utilizing CT techniques are reviewed. Although results from the Lund-Mackay system appear to be easily reproducible. there are still clinical challenges not addressed by this method of classification. Considering the patency of specific ostiomeatal channels and quantifying the volume of disease may add to the clinical value of future classification systems.
OBJECTIVE: Patients with superior canal dehiscence (SCD) syndrome experience vertigo and oscillopsia with loud sounds and/or stimuli that result in changes in middle ear or intracranial pressure. Findings on temporal bone CT were analyzed to determine if a developmental abnormality is associated with the syndrome. MATERIAL AND METHODS: Temporal bone CT scans [0.5 mm collimation and projections into the superior semicircular canal (SC) plane] were used to compare the bone overlying the SC in patients with SCD syndrome (20 unilateral, 7 bilateral) and in 88 patients without SCD syndrome who had undergone temporal bone CT for evaluation of other otologic disorders (controls). RESULTS: The thickness of bone overlying the SC in the controls measured 0.67 +/- 0.38 mm (mean +/- SD). For individual control subjects. the thickness of bone on one side was correlated with that on the other side (r = 0.43; p < 0.0001). The thickness of bone overlying the SC on the intact side in patients with unilateral dehiscence measured 0.31 +/- 0.23 mm, and was thinner than that noted in the controls (p < 0.0001). CONCLUSION: These findings support the notion that there is a developmental abnormality underlying SCD syndrome. When dehiscence is found on one side, the contralateral side is likely to be thin.
PURPOSE: To describe the computed tomographic (CT) findings at different collimation widths associated with superior semicircular canal (SSC) dehiscence syndrome and to determine the frequency of these findings in a control population. MATERIALS AND METHODS: Temporal bone CT scans with 1.0-mm and/or 0.5-mm collimation were obtained in 50 patients with sound- and/or pressure-induced vestibular symptoms. The control population consisted of 50 patients undergoing CT at 1.0-mm collimation and 57 patients undergoing CT at 0.5-mm collimation for other reasons. RESULTS: SSC dehiscence was documented on CT scans in all 36 patients with the clinical syndrome, with bilateral findings in six patients. Six other patients without specific clinical signs appeared to have dehiscence on 1.0-mm-collimated scans. Intact bone overlaying the SSC was subsequently identified with 0.5-mm-collimated CT in each case. On the 1.0-mm-collimated scans in 50 control patients, an area judged as possible or definite dehiscence was identified in 18 of 100 ears. The bone overlaying the SSC was intact in each of the 114 control ears evaluated with 0.5-mm-collimated CT. CT findings from the patients with vestibular symptoms combined with those in the control population indicated that the positive predictive value of an apparent dehiscence in the diagnosis of SSC dehiscence syndrome improved from 50% with 1.0-mm-collimated CT with transverse and coronal images to 93% with 0.5-mm-collimated CT with reformation in the plane of the SSC. CONCLUSION: The positive predictive value of CT in identification of SSC dehiscence syndrome improves with 0.5-mm-collimated helical CT and reformation in the SSC plane.
OBJECTIVE: The aim of this study was to identify recognizable landmarks on coronal CT (CCT) scans for the localization of the anterior and posterior ethmoid arteries, which are important anatomic structures and surgical landmarks within the ethmoid sinuses. MATERIALS AND METHODS: Four series of plastinated cadaver specimens and 80 CCT examinations were evaluated to identify the anatomical landmarks that define the course of the anterior and posterior ethmoid arteries within the ethmoid sinuses. RESULTS: The following anatomic landmarks: the indentations into the medial orbital wall, the relationship between the superior oblique and medial rectus orbital muscles, and the lateral ethmoid fovea wall thinning proved to be useful CCT landmarks for the localization of the anterior and posterior ethmoid arteries. CONCLUSION: The results of this study suggest that familiarity with the above-mentioned landmarks on routine CCT images facilitates the localization of the anterior and posterior ethmoid arteries as they enter the ethmoid sinus.
Computer-assisted pedicle screw insertion is feasible but has proved to be problematic. The purpose of this study was to detail the accuracy of registration techniques and pedicle screw insertion using a frameless stereotactic system. Two registration techniques were evaluated on a model spine. The frameless stereotactic system was then used to insert 26 pedicle and 8 lateral mass screws in human cadavers. For posterior vertebral elements, trajectory accuracy was 2.5 +/- 1.0 mm between T12 and L5 and 2.2 +/- 0.9 mm between C2 and T1. Registration of the anterior elements, however, was less accurate. Despite this flaw, all screws were inserted without penetrating the cortex. Screw trajectory was accurate to 2 degrees. The main limitation of frameless stereotactic surgery in the spine stems from the fact that only the posterior vertebral elements are used during registration. Despite this flaw, the system placed all screws correctly. Given these limitations, we believe that this system is most useful for locating the screw insertion point and providing a trajectory in the pedicle.
Imaging modalities have become increasingly significant in the treatment of laryngeal cancer. The ability of CT and MR imaging to reveal pathologic conditions that are undetectable by palpation or endoscopy has led to the development of several imaging-based systems of anatomic classification and tumor staging. This article provides an up-to-date review of the radiographic evaluation of the normal neck and information for both the radiologist and clinician treating the patient with laryngeal cancer. Technical considerations, imaging-based staging systems, and the radiographic characteristics of laryngeal cancer in various regions of the neck are discussed.
BACKGROUND: Mometasone furoate nasal spray (MFNS) 400 microg, twice daily, as adjunctive treatment with oral antibiotic significantly improved symptoms of recurrent rhinosinusitis. OBJECTIVE: To evaluate the effectiveness and safety of MFNS 200 microg, twice daily, and 400 microg, twice daily, compared with placebo as adjunctive treatment with oral antibiotic for acute rhinosinusitis. METHODS: In this multicenter, double-blind, placebo-controlled study, 967 outpatients with computed tomographic scan-confirmed moderate to severe rhinosinusitis received amoxicillin/clavulanate potassium (Augmentin, GlaxoSmithKline, Research Triangle Park, NC) 875 mg, twice daily, for 21 days with adjunctive twice daily MFNS 200 microg, MFNS 400 microg, or placebo nasal spray. Patients recorded scores of six rhinosinusitis symptoms and any adverse events twice daily. Pre- and postcosyntropin-stimulation plasma cortisol levels were measured in a subset of patients at selected study sites. RESULTS: Treatment with MFNS 200 microg or 400 microg, twice daily, produced significantly greater improvements in total symptoms score (primary efficacy variable) day 1 to day 15 average (50% and 51%, respectively) than placebo (44%, P < or = 0.017). Both doses of MFNS produced significant total symptoms score improvement over placebo by day 4, and maintained efficacy over the entire 21-day study. Relief of individual symptoms showed a similar pattern. Both doses of MFNS were well tolerated, and adverse events were similar to that of placebo. Cosyntropin stimulation showed no evidence of hypothalamic-pituitary-adrenal axis suppression. CONCLUSIONS: As adjunctive therapy to oral antibiotic treatment, MFNS at doses of 200 microg or 400 microg, twice daily, was well tolerated and significantly more effective in reducing the symptoms of rhinosinusitis than antibiotic therapy alone.
PURPOSE: To evaluate the dimensions of specific white matter tracts in the brainstems (region of brain thought to be least affected) of children with holoprosencephaly by using diffusion tensor magnetic resonance (MR) imaging and to correlate these abnormalities with forebrain malformation severity and neurologic deficit severity. MATERIALS AND METHODS: Thirteen patients with holoprosencephaly underwent diffusion tensor MR imaging, with which white matter color maps were generated. Type of holoprosencephaly was correlated with presence or absence of specific brainstem white matter tracts. Furthermore, patient rank based on cortico-ponto-spinal tract (CPST) and middle cerebellar peduncle (MCP) dimensions was correlated with holoprosencephaly type and neurodevelopmental score by using Spearman rank correlation analysis. RESULTS: Two patients had alobar holoprosencephaly, five had the semilobar type, one had the lobar type, and one had the middle-hemisphere-variant type. Four patients were excluded from analysis. In the two patients with alobar holoprosencephaly, the CPSTs were absent bilaterally. In all of the remaining patients except one, who had semilobar holoprosencephaly in which the CPSTs could not be identified at the level of the medulla oblongata, all tracts were present bilaterally. Holoprosencephaly type and neurodevelopmental score correlated strongly with CPST and MCP dimensions (P <.01) over and above the effect of age. CONCLUSION: In vivo identification of brainstem white matter tract abnormalities in patients with holoprosencephaly can be achieved by performing diffusion tensor MR imaging.