CT of scoliotic patients after myelography: value of lateral decubitus positioning.

In routine computed tomography (CT) of scoliotic patients, multiple scans through each intervertebral disk level must be made, which can make interpretation of disks and neural foramina difficult. Use of lateral decubitus positioning for postmyelography CT allows use of gantry angulation to achieve true axial scans through disks, which permits easier evaluation of individual disks and foramina.     

Intrarenal arterial Doppler sonography in patients with nonobstructive renal disease: correlation of resistive index with biopsy findings

The resistive index (RI), calculated from the duplex Doppler waveform, was compared with clinical and laboratory findings and the results of renal biopsy in 41 patients with nonobstructive (medical) renal disease. Kidneys with active disease in the tubulointerstitial compartment had a mean RI of 0.75 +/- 0.07. This was statistically significantly different (p less than .01) from the RI in kidneys with disease limited to the glomeruli (mean RI of 0.58 +/- 0.05). Acute tubular necrosis resulted in an elevated RI (mean RI = 0.78 +/- 0.03) as did vasculitis/vasculopathy (mean RI = 0.82 +/- 0.05). Patients with hypertension, proteinuria, or hematuria did not have kidneys with a significantly higher RI than did patients without these clinical factors. Kidneys found to be abnormally echogenic did not have an RI significantly different from kidneys of normal echogenicity. There was a weak correlation between creatinine level and RI value, reflected by a linear correlation coefficient of 0.34. In patients with normal renal RIs, the mean creatinine level was 1.7 +/- 1.7, whereas in those with abnormal RI values (greater than or equal to 0.70), the mean creatinine level was 3.7 +/- 3.6. We conclude that some forms of nonobstructive renal disease can produce changes in the Doppler waveform detectable by RI measurement. The production of Doppler waveform changes is strongly influenced by the site of the main disease within the kidneys. Active disease within the tubulointerstitial compartment (acute tubular necrosis, interstitial nephritis) or vasculitis/vasculopathy generally resulted in an elevated RI, whereas disease limited to the glomeruli, no matter how severe, did not significantly elevate the RI. Degree of renal dysfunction as indicated by serum creatinine level probably affects the Doppler waveform to some degree, but the relationship is weak.     

Neurologic complications of cerebral angiography.

PURPOSETo examine the incidence of neurologic complications associated with modern cerebral angiography and to assess patient characteristics associated with an increased risk of complications.METHODSOne thousand consecutive cerebral angiographic procedures were evaluated prospectively. Examinations were performed using transfemoral catheterization and film-screen methods. For purposes of this trial, a neurologic complication was defined as any new focal neurologic deficit or change in mental status occurring during the angiogram or within the following 24 hours. Patients were evaluated during and at the completion of angiography. Follow-up evaluations were performed on the day of and the day after angiography.RESULTSThere were a total of 10 neurologic complications within 24 hours of angiography, 5 of which were persistent. Onset of 5 of the deficits occurred during angiography, the other 5 (3 persistent) were delayed. All complications occurred in patients being evaluated for stroke/transient ischemic attack or (in one case) asymptomatic bruit. A higher average age, longer average procedure time, and greater volume of radiographic contrast was noted in these patients than in the study population.CONCLUSIONCerebral angiography was associated with a 1% overall incidence of neurologic deficit and a 0.5% incidence of persistent deficit. All complications occurred in patients presenting with a history of stroke/transient ischemic accident or carotid bruit, which may reflect the difficulty of performing angiography in this population at risk for atherosclerotic changes.     

The value of CT in the detection of bladder and posterior urethral injuries

To determine the value of CT in the diagnosis of bladder and posterior urethral injuries, we retrospectively evaluated the CT and urethrocystographic findings in 33 trauma patients with suspected injuries of the lower urinary tract who had both studies in their initial evaluation. In 26 (79%) of 33 patients, results of both examinations were normal. Seven (21%) of 33 patients had bladder injuries (seven--two in one patient) and/or posterior urethral injuries (three) as determined on the basis of urethrocystography. Three patients had extraperitoneal bladder tears as the only injury to the lower urinary tract. Two patients had both extraperitoneal bladder tears and posterior urethral injuries. One patient had both an extraperitoneal tear at the bladder base and an intraperitoneal rupture at the bladder dome. The seventh patient had an isolated posterior urethral injury. All seven bladder injuries were detected with CT. In these cases, CT findings included (1) free intraperitoneal contrast material (one case), (2) focal contrast extravasation (three cases), and (3) paravesical fluid collections that on delayed CT scans revealed contrast accumulation in the fluid, indicating extravasation (two cases). The seventh bladder injury was suspected on CT and confirmed with retrograde urethrography. Only one of three posterior urethral injuries was detected with CT. Our results suggest that CT is sensitive in the detection of bladder injuries, but not for the diagnosis of urethral injuries.     

Carbon dioxide gas as a venous contrast agent to guide upper-arm insertion of central venous catheters

Purpose Evaluate in a prospective randomized study carbon dioxide (CO₂) gas compared to iodinated contrast agent for image-guided placement of peripherally inserted central venous catheters (PICCs).Methods The upper-arm approach to the central vein was used for placement of PICCs in 74 patients requiring intermediate or long-term central venous access. Fluoroscopy was used to obtain venous access during peripheral injection of CO₂ (n = 41) or low osmolar contrast material (Omnipaque 240 mgI/ml) (n = 33).Results Placement of PICCs was accomplished in 88% of the CO₂ group and in 100% of the contrast group, with a mean venipuncture of two in both groups. Venous access was unsuccessful in five patients with CO₂ due to a small vein, venous spasm, or technical failure. The mean and range of procedure times were 22.8 min (13–64 min) with CO₂ and 23.2 min (12–60 min) with contrast material. The average and range of CO₂ and nonionic contrast volumes injected during the procedure were 35.4 ml (5–300 ml) and 27.8 ml (8–120 ml), respectively. Vital signs and oxygen saturation did not change significantly during or after injection of CO₂. There was no incidence of adverse reaction following CO₂ injection.Conclusion CO₂ gas is a useful contrast agent to guide upper-arm insertion of PICCs and may be a safe alternative in patients with renal insufficiency and/or allergy to iodinated contrast material.     

Intraoperative spinal sonography in the evaluation of intramedullary tumors

Seventeen intraoperative spinal sonographic examinations were performed in 14 patients with intramedullary spinal cord neoplasms. Results of the ultrasound exams were correlated with preoperative imaging studies, surgical findings, and histopathologic analysis of the tumors. Intraoperative spinal sonography accurately localized the intramedullary tumors, often revealing the need for extension of the initial laminectomy. The neoplasms appeared as expansile echogenic masses, with cystic components in over half. Ultrasound was as accurate as preoperative imaging in the evaluation of solid neoplasms, and was superior to computed tomography (CT) and magnetic resonance imaging (MRI) for delineating the cystic components of neoplasms. Intraoperative sonography should be used routinely in all surgical cases of intramedullary spinal cord neoplasms.     

Public citizens, marginalized communities: the struggle for syringe exchange in Springfield, Massachusetts

Syringe exchange programs, which, in order to prevent HIV infections, provide injection drug users with sterile syringes in exchange for used ones, operate at the intersection of conflicting social and political beliefs about disease, drugs, the common good, and the law. This paper describes community opposition that emerged from diverse quarters in response to a proposed syringe exchange program (SEP) in Springfield, Massachusetts. White suburban residents and inner-city African-Americans both drew on concepts of personal responsibility and self-sufficiency as they described their opposition to SEP. Through archival research and in-depth interviews with key community figures, I show how their similar political positions resulted from highly divergent views on the role of government in caring for citizens and communities. These arguments about addiction, HIV, and community both index and turn on the unique relationships with government experienced by a range of social actors.     

Overview of adrenal imaging/adrenal CT

CT is the imaging procedure of choice for the detection of most suspected adrenal masses. But except for some patients with acute adrenal hemorrhage or fat-containing myelolipoma, the precise histologic nature of an adrenal mass is not apparent from the CT image. MIBG radionuclide scanning is useful in some patients with pheochromocytoma, whereas bilateral adrenal venous sampling for hormone assay is necessary for correct lateralization in some patients with a small aldosterone-producing adenoma. The potential value of MR imaging in the characterization of adrenal masses, especially to distinguish benign adrenal cortical adenomas from metastatic disease, is now under investigation. Currently percutaneous aspiration biopsy is still necessary to make this distinction in patients with an adrenal mass and a known extra-adrenal primary neoplasm.     

Enhanced magnitude and breadth of neutralizing humoral response to a DNA vaccine targeting the DHBV envelope protein delivered by in vivo electroporation

We explored in the duck hepatitis B virus (DHBV) model the impact of electroporation (EP)-mediated DNA vaccine delivery on the neutralizing humoral response to viral preS/S large envelope protein. EP enhanced the kinetics and magnitude of anti-preS response compared to the standard needle DNA injection (SI). Importantly, EP dramatically enhanced the neutralizing potency of the humoral response, since antibodies induced by low DNA dose (10 μg) were able to highly neutralize DHBV and to recognize ten antigenic regions, including four neutralization epitopes. Whereas, SI-induced antibodies by the same low DNA dose were not neutralizing and the epitope pattern was extremely narrow, since it was limited to only one epitope. Thus, EP-based delivery was able to improve the dose efficiency of DNA vaccine and to maintain a highly neutralizing, multi-specific B-cell response, suggesting that it may be an effective approach for chronic hepatitis B therapy at clinically feasible DNA dose.