Superficial siderosis associated with an iatrogenic posterior fossa dural leak identified on CT cisternography

Superficial siderosis refers to hemosiderin deposition along the pial surface of the brain and spinal cord. It results from chronic and repetitive low-grade bleeding into the subarachnoid space. Dural tears are a common cause of superficial siderosis. Although such tears typically occur in the spine, dural tears can also occur in the posterior fossa. In many cases, posterior fossa dural tears are iatrogenic, and patients may present with neuroimaging evidence of postoperative pseudomeningoceles. We present a case of superficial siderosis caused by a persistent posterior fossa dural leak. The patient presented with superficial siderosis 30 years after a Chiari I malformation repair. A pinhole-sized dural tear was identified preoperatively using computed tomography cisternography. The dural defect was successfully repaired. An additional small tear that was not seen on imaging was also identified at surgery and successfully repaired.

e-ASPECTS software improves interobserver agreement and accuracy of interpretation of aspects score

INTRODUCTION

There is increased interest in the use of artificial intelligence-based (AI) software packages in the evaluation of neuroimaging studies for acute ischemic stroke. We studied whether, compared to standard image interpretation without AI, Brainomix e-ASPECTS software improved interobserver agreement and accuracy in detecting ASPECTS regions affected in anterior circulation LVO.

METHODS

We included 60 consecutive patients with anterior circulation LVO who had TICI 3 revascularization within 60 minutes of their baseline CT. A total of 16 readers, including senior neuroradiologists, junior neuroradiologists and vascular neurologists participated. Readers interpreted CT scans on independent workstations and assessed final ASPECTS and evaluated whether each individual ASPECTS region was affected. Two months later, readers again evaluated the CT scans, but with assistance of e-ASPECTS software. We assessed interclass correlation coefficient for total ASPECTS and interobserver agreement with Fleiss' Kappa for each ASPECTS region with and without assistance of the e-ASPECTS. We also assessed accuracy for the readers with and without e-ASPECTS assistance. In our assessment of accuracy, ground truth was the 24 hour CT in this cohort of patients who had prompt and complete revascularization.

RESULTS

Interclass correlation coefficient for total ASPECTS without e-ASPECTS assistance was 0.395, indicating fair agreement compared, to 0.574 with e-ASPECTS assistance, indicating good agreement (P < 0.01). There was significant improvement in inter-rater agreement with e-ASPECTS assistance for each individual region with the exception of M6 and caudate. The e-ASPECTS software had higher accuracy than the overall cohort of readers (with and without e-ASPECTS assistance) for every region except the caudate.

CONCLUSIONS

Use of Brainomix e-ASPECTS software resulted in significant improvements in inter-rater agreement and accuracy of ASPECTS score evaluation in a large group of neuroradiologists and neurologists. e-ASPECTS software was more predictive of final infarct/ASPECTS than the overall group interpreting the CT scans with and without e-ASPECTS assistance.

The Central Dot Sign : A Specific Post-gadolinium Enhancement Feature of Intramedullary Spinal Cord Metastases

PURPOSE

Peripheral enhancement characteristics on magnetic resonance imaging (MRI), namely the rim and flame signs, are specific for intramedullary spinal cord metastases (ISCM) compared to primary cord masses. The study compared the frequency of a novel finding-the central dot sign-in ISCMs versus primary intramedullary masses.

METHODS

In this study 45 patients with 64 ISCMs and 64 control patients with 64 primary intramedullary cord masses were investigated and 2 radiologists blinded to lesion type independently evaluated MR images for the presence of a central dot sign: a punctate focus of enhancement in/near the center of an enhancing intramedullary mass. The frequency of this sign in the two patient groups was compared.

RESULTS

A total of 63 enhancing ISCMs in 44 patients and 54 enhancing primary cord masses in 54 patients were included. The central dot sign was identified in 6% (4/63) of enhancing ISCMs in 9% (4/44) of patients and in none (0/54) of the enhancing primary cord masses (p = 0.038, per patient). The specificity for diagnosing ISCMs among spinal cord masses was 100%. The central dot sign was present in the axial plane only in two ISCMs and in the axial and sagittal planes in two ISCMs. The two ISCMs harboring the central dot sign also demonstrated both the previously described rim and flame signs, and two also demonstrated the rim sign alone.

CONCLUSION

The central dot sign is not sensitive but highly specific for ISCMs compared to primary spinal cord masses. The rim and/or flame signs may or may not be concurrently present in ISCMs.

Perinatal outcomes among young donor oocyte recipients

STUDY QUESTION

Is the use of donor oocytes in women <35 years of age associated with an increased risk of adverse perinatal outcomes compared to use of autologous oocytes?

SUMMARY ANSWER

Among fresh assisted reproductive technology (ART) cycles performed in women under age 35, donor oocyte use is associated with a higher risk of preterm birth, low birth weight and stillbirth (when zero embryos were cryopreserved) as compared to autologous oocytes.

WHAT IS KNOWN ALREADY

Previous studies demonstrated elevated risk of poor perinatal outcomes with donor versus autologous oocytes during ART, primarily among older women.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study using data reported to Centers for Disease Control and Prevention's National ART Surveillance System (NASS) during the period from 2010 to 2015 in order to best reflect advances in clinical practice. Approximately 98% of all US ART cycles are reported to NASS, and discrepancy rates were <6% for all fields evaluated in 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included all non-banking fresh and frozen ART cycles performed between 2010 and 2015 in women under age 35 using autologous or donor eggs. Cycles using cryopreserved eggs, donated embryos or a gestational carrier were excluded. Among fresh embryo transfer cycles, we calculated predicted marginal proportions to estimate the unadjusted and adjusted risk ratios (aRRs) and 95% confidence intervals (CIs) for the association between donor versus autologous oocyte use and stillbirth, spontaneous abortion, preterm delivery and low birth weight among singleton pregnancies or births. Stillbirth models were stratified by number of embryos cryopreserved. All models were adjusted for patient and treatment characteristics.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the 71 720 singleton pregnancies occurring during 2010-2015, singletons resulting from donor oocytes were more likely to be preterm (15.6% versus 11.0%; aRRs 1.39: CI 1.20-1.61) and have low birth weight (11.8% versus 8.8%; aRRs 1.34; CI 1.16-1.55) than those resulting from autologous oocytes. With zero embryos cryopreserved, donor versus autologous oocyte use was associated with increased risk for stillbirth (2.1% versus 0.6%; aRRs 3.73; CI 1.96-7.11); no association with stillbirth was found when ≥1 embryo was cryopreserved (0.54% versus 0.56%; aRR 1.15; CI 0.59-2.25).

LIMITATIONS, REASONS FOR CAUTION

The data come from a national surveillance system and is thus limited by the accuracy of the data entered by individual providers and clinics. There may be unmeasured differences between women using donor eggs versus their own eggs that could be contributing to the reported associations. Given the large sample size, statistically significant findings may not reflect clinically important variations.

WIDER IMPLICATIONS OF THE FINDINGS

Risks of preterm birth, low birth weight and stillbirth among singleton pregnancies using donor oocytes were increased compared to those using autologous oocytes. Further study regarding the pathophysiology of the potentially increased risks among donor oocyte recipient pregnancy is warranted.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

Traumatic anterior cervical pseudomeningocele causing intracranial hypotension successfully treated with blood patch: case report

Cervical pseudomeningocele is a rare complication of trauma. It develops when an extradural collection of cerebrospinal fluid (CSF) develops after a dural breach. The authors present the unusual case of a 33-year-old man with progressive headache, neck pain, mental status changes, and cardiopulmonary instability after polytrauma sustained from a motorcycle-versus-deer collision, without improvement during a 5-day hospitalization. Magnetic resonance imaging revealed a collection of CSF anterior to the cervical thecal sac compatible with an anterior cervical pseudomeningocele. A nontargeted epidural blood patch was performed with subsequent resolution of the patient's symptoms. Anterior cervical pseudomeningoceles are usually asymptomatic; however, these lesions can cause orthostatic headaches, neck pain, and cardiopulmonary compromise, as it did in the featured patient. Pseudomeningoceles should be included in the differential diagnosis for posttrauma patients with progressive neurological decline or postural headache, and blood patch may be an effective minimally invasive treatment.

The effects of changes in utilization and technological advancements of cross-sectional imaging on radiologist workload

RATIONALE AND OBJECTIVES

To examine the effect of changes in utilization and advances in cross-sectional imaging on radiologists' workload.

MATERIALS AND METHODS

All computed tomography (CT) and magnetic resonance imaging (MRI) examinations performed at a single institution between 1999 and 2010 were identified and associated with the total number of images for each examination. Annual trends in institutional numbers of interpreted examinations and images were translated to changes in daily workload for the individual radiologist by normalizing to the number of dedicated daily CT and MRI work assignments, assuming a 255-day/8-hour work day schedule. Temporal changes in institutional and individual workload were assessed by Sen's slope analysis (Q = median slope) and Mann-Kendall test (Z = Z statistic).

RESULTS

From 1999 to 2010, a total of 1,517,149 cross-sectional imaging studies (CT = 994,471; MRI = 522,678) comprising 539,210,581 images (CT = 339,830,947; MRI = 199,379,634) were evaluated at our institution. Total annual cross-sectional studies steadily increased from 84,409 in 1999 to 147,336 in 2010, representing a twofold increase in workload (Q = 6465/year, Z = 4.2, P < .0001). Concomitantly, the number of annual departmental cross-sectional images interpreted increased from 9,294,140 in 1990 to 94,271,551 in 2010, representing a 10-fold increase (Q = 8707876/year, Z = 4.5, P < .0001). Adjusting for staffing changes, the number of images requiring interpretation per minute of every workday per staff radiologist increased from 2.9 in 1999 to 16.1 in 2010 (Q = 1.7/year, Z = 4.3, P < .0001).

CONCLUSIONS

Imaging volumes have grown at a disproportionate rate to imaging utilization increases at our institution. The average radiologist interpreting CT or MRI examinations must now interpret one image every 3-4 seconds in an 8-hour workday to meet workload demands.

Increasing neuroradiology exam volumes on-call do not result in increased major discrepancies in primary reads performed by residents

Background and Purpose:

A common perception is that increased on-call workload leads to increased resident mistakes. To test this, we evaluated whether increased imaging volume has led to increased errors by residents.

Materials and Methods:

A retrospective review was made of all overnight neuroradiology CT exams with a primary resident read from 2006-2010. All studies were over-read by staff neuroradiologists next morning. As the volume is higher on Friday through Sunday nights, weekend studies were examined separately. Discrepancies were classified as either minor or major. “Major” discrepancy was defined as a discrepancy that the staff radiologist felt was significant enough to potentially affect patient care, necessitating a corrected report and phone contact with the ordering physician and documentation. The total number of major discrepancies was recorded by quarter. In addition, the total number of neuroradiology CT studies read overnight on-call was noted.

Results:

The mean number of cases per night during the weekday increased from 3.0 in 2006 to 5.2 in 2010 (p<0.001). During the weekend, the mean number of cases per night increased from 5.4 in 2006 to 7.6 in 2010 (p<0.001). Despite this increase, the major discrepancy rate decreased from 2.7% in 2006 to 2.3% in 2010 (p=0.34).

Conclusion:

Despite an increase in neuroradiology exam volumes, there continues to be a low major discrepancy rate for primary resident interpretations. While continued surveillance of on-call volumes is crucial to the educational environment, concern of increased major errors should not be used as sole justification to limit autonomy.

Intramedullary spinal cord metastases: prognostic value of MRI and clinical features from a 13-year institutional case series

BACKGROUND AND PURPOSE

In patients with intramedullary spinal cord metastases, the impact of MR imaging and clinical characteristics on survival has not been elucidated. Our aim was to identify MR imaging and clinical features with prognostic value among patients with intramedullary spinal cord metastases from a large retrospective series.

MATERIALS AND METHODS

The relevant MR imaging examination and baseline clinical data for each patient from a consecutive group of patients with intramedullary spinal cord metastases had previously been reviewed by 2 neuroradiologists. Additional relevant clinical data were extracted. The influence of clinical and imaging characteristics on survival was assessed by Kaplan-Meier survival curves and log-rank tests for categoric characteristics.

RESULTS

Forty-nine patients had 70 intramedullary spinal cord metastases; 10 (20%) of these patients had multiple metastases. From the date of diagnosis, median survival for all patients was 104 days (95% CI, 48-156 days). One clinical feature was associated with decreased median survival: lung or breast primary malignancy (57 days) compared with all other malignancy types (308 days; P < .001). Three MR imaging features were associated with decreased median survival: multiple intramedullary spinal cord metastases (53 versus 121 days, P = .022), greater longitudinal extent of cord T2 hyperintensity (if ≥3 segments, 111 days; if ≤2, 184 days; P = .018), and ancillary visualization of the primary tumor and/or non-CNS metastases (96 versus 316 days, P = .012).

CONCLUSIONS

Spinal cord edema spanning multiple segments, the presence of multifocal intramedullary spinal cord metastases, and ancillary evidence for non-CNS metastases and/or the primary tumor are MR imaging features associated with decreased survival and should be specifically sought. Patients with either a lung or breast primary malignancy are expected to have decreased survival compared with other primary tumor types.

Immunoglobulin G4-related disease of the orbit: imaging features in 27 patients

BACKGROUND AND PURPOSE

Immunoglobulin G4-related disease is a systemic fibroinflammatory process of unknown etiology, characterized by tissue infiltration by immunoglobulin G4 plasma cells. The purpose of this study was to retrospectively identify the spectrum of imaging features seen in immunoglobulin G4-related disease of the orbit.

MATERIALS AND METHODS

This study included 27 patients with biopsy-proved immunoglobulin G4-related disease of the orbit and either a CT or MR imaging of the orbits. These CT or MR imaging examinations were evaluated for the following: extraocular muscle size, extraocular muscle tendon enlargement, lacrimal gland enlargement, infiltrative process in the orbital fat (increased attenuation on CT or abnormal signal on MR imaging), infraorbital nerve enlargement, mucosal thickening in the paranasal sinuses, and extension of orbital findings intracranially.

RESULTS

Extraocular muscles were enlarged in 24 of 27 (89%) patients, 21 (88%) bilaterally. In 32 of 45 (71%) affected orbits, the lateral rectus was the most enlarged muscle. In 26 (96%) patients, the tendons of the extraocular muscles were spared. Nineteen (70%) patients had lacrimal gland enlargement. Twelve (44%) patients had an infiltrative process within the orbital fat. Infraorbital nerve enlargement was seen in 8 (30%) patients. Twenty-four (89%) patients had sinus disease. Cavernous sinus or Meckel cave extension was seen in 3 (11%) patients.

CONCLUSIONS

In patients with extraocular muscle enlargement, particularly when the tendons are spared and the lateral rectus is the most enlarged, and even more so when other noted findings are present, immunoglobulin G4-related disease should be a leading differential consideration, even over more commonly known etiologies of extraocular muscle enlargement.

Tympanic plate fractures in temporal bone trauma: prevalence and associated injuries

BACKGROUND AND PURPOSE

The prevalence of tympanic plate fractures, which are associated with an increased risk of external auditory canal stenosis following temporal bone trauma, is unknown. A review of posttraumatic high-resolution CT temporal bone examinations was performed to determine the prevalence of tympanic plate fractures and to identify any associated temporal bone injuries.

MATERIALS AND METHODS

A retrospective review was performed to evaluate patients with head trauma who underwent emergent high-resolution CT examinations of the temporal bone from July 2006 to March 2012. Fractures were identified and assessed for orientation; involvement of the tympanic plate, scutum, bony labyrinth, facial nerve canal, and temporomandibular joint; and ossicular chain disruption.

RESULTS

Thirty-nine patients (41.3 ± 17.2 years of age) had a total of 46 temporal bone fractures (7 bilateral). Tympanic plate fractures were identified in 27 (58.7%) of these 46 fractures. Ossicular disruption occurred in 17 (37.0%). Fractures involving the scutum occurred in 25 (54.4%). None of the 46 fractured temporal bones had a mandibular condyle dislocation or fracture. Of the 27 cases of tympanic plate fractures, 14 (51.8%) had ossicular disruption (P = .016) and 18 (66.6%) had a fracture of the scutum (P = .044). Temporomandibular joint gas was seen in 15 (33%) but was not statistically associated with tympanic plate fracture (P = .21).

CONCLUSIONS

Tympanic plate fractures are commonly seen on high-resolution CT performed for evaluation of temporal bone trauma. It is important to recognize these fractures to avoid the preventable complication of external auditory canal stenosis and the potential for conductive hearing loss due to a fracture involving the scutum or ossicular chain.

Intramedullary spinal cord metastases: visibility on PET and correlation with MRI features

BACKGROUND AND PURPOSE

Studies systematically evaluating the detection of intramedullary spinal cord metastasis with PET are lacking. Our purpose was to evaluate the visibility of intramedullary spinal cord metastasis on PET in a single institutional series and to correlate PET and MR imaging features.

MATERIALS AND METHODS

Patients were included if pretreatment MR imaging identifying an intramedullary spinal cord metastasis and an [(18)F] FDG-PET examination near the time of MR imaging were available. PET examinations were retrospectively reviewed, with reviewers blinded and then unblinded to the PET report and MR imaging findings. PET intramedullary spinal cord metastasis features were compared with and correlated with previously analyzed MR imaging lesion characteristics. Original clinical PET reports were reviewed.

RESULTS

The final study sample was 10 PET examinations in 10 patients with 13 intramedullary spinal cord metastases. In 7 (70%) patients, retrospective blinded review demonstrated convincing evidence of 10 (77%) intramedullary spinal cord metastases. Three MR imaging features correlated with intramedullary spinal cord metastases being visible on PET compared with those nonvisible, respectively: larger lesion enhancement size: mean size: 32.1 mm versus 6.0 mm (P = .038); larger longitudinal extent of T2 signal abnormality: mean 5.6 versus 1.0 segments (P = .0081); and larger ratio of extent of T2 signal abnormality to contrast enhancement: 3.8 versus 1.0 (P = .0069). Intramedullary spinal cord metastasis was confidently reported clinically in 2 (20%) patients, accounting for 5 (38%) intramedullary spinal cord metastases.

CONCLUSIONS

Most intramedullary spinal cord metastases can be detected on PET when performed near the time of pretreatment MR imaging. However, intramedullary spinal cord metastases may not be clinically reported on PET. Larger lesions with more edema are more likely to be visible. The spinal cord should be specifically and carefully assessed on PET for evidence of intramedullary spinal cord metastases to provide timely diagnosis.

Intracranial imaging of uncommon diseases is more frequently reported in clinical publications than in radiology publications

BACKGROUND AND PURPOSE

Descriptions of uncommon diseases with intracranial imaging abnormalities are often difficult to find in the radiology literature. We hypothesized that reported imaging findings of such conditions in the recent literature were more frequent in clinical compared with radiology journals.

MATERIALS AND METHODS

PubMed searches from December 1, 2007 to December 1, 2012 were performed for 5 uncommon CNS diseases with intracranial imaging manifestations: 1) Susac syndrome; 2) amyloid β-related angiitis; 3) Parry-Romberg syndrome/en coup de sabre; 4) transient lesion of the splenium of the corpus callosum; and 5) reversible cerebral vasoconstriction syndrome. Articles were classified as a case report, case series, or original research. Journals were categorized as radiology or clinical. The 1- and 5-year Impact Factors of the journals were recorded.

RESULTS

Two hundred two articles were identified for the 5 diseases, including 151 (74%) case reports, 26 case series (13%), and 25 original research articles (13%); 179 (89%) were published in nonradiology journals, compared with 23 (11%) in radiology journals. There was no significant difference between the mean 1- and 5-year Impact Factors of the radiology and clinical journals.

CONCLUSIONS

Recent reports of the selected uncommon diseases with intracranial manifestations are more frequent in clinical journals when compared with dedicated radiology publications. Most publications are case reports. Radiologists should review both radiology and clinical journals when reviewing imaging features of uncommon diseases affecting the brain. Lack of reporting on such disease in the radiology literature may have significant practice, educational, and research implications for the radiology community.

Intramedullary spinal cord metastases: MRI and relevant clinical features from a 13-year institutional case series

BACKGROUND AND PURPOSE

Because intramedullary spinal cord metastasis is often a difficult diagnosis to make, our purpose was to perform a systematic review of the MR imaging and relevant baseline clinical features of intramedullary spinal cord metastases in a large series.

MATERIALS AND METHODS

Consecutive patients with intramedullary spinal cord metastasis with available pretreatment digital MR imaging examinations were identified. The MR imaging examination(s) for each patient was reviewed by 2 neuroradiologists for various imaging characteristics. Relevant clinical data were obtained.

RESULTS

Forty-nine patients had 70 intramedullary spinal cord metastases, with 10 (20%) having multiple intramedullary spinal cord metastases; 8% (4/49) were asymptomatic. Primary tumor diagnosis was preceded by intramedullary spinal cord metastasis presentation in 20% (10/49) and by intramedullary spinal cord metastasis diagnosis in 10% (5/49); 98% (63/64) of intramedullary spinal cord metastases enhanced. Cord edema was extensive: mean, 4.5 segments, 3.6-fold larger than enhancing lesion, and ≥3 segments in 54% (37/69). Intratumoral cystic change was seen in 3% (2/70) and hemorrhage in 1% (1/70); 59% (29/49) of reference MR imaging examinations displayed other CNS or spinal (non-spinal cord) metastases, and 59% (29/49) exhibited the primary tumor/non-CNS metastases, with 88% (43/49) displaying ≥1 finding and 31% (15/49) displaying both findings. Patients with solitary intramedullary spinal cord metastasis were less likely than those with multiple intramedullary spinal cord metastases to have other CNS or spinal (non-spinal cord) metastases on the reference MR imaging (20/39 [51%] versus 9/10 [90%], respectively; P = .0263).

CONCLUSIONS

Lack of known primary malignancy or spinal cord symptoms should not discourage consideration of intramedullary spinal cord metastasis. Enhancement and extensive edema for lesion size (often ≥3 segments) are typical for intramedullary spinal cord metastasis. Presence of cystic change/hemorrhage makes intramedullary spinal cord metastasis unlikely. Evidence for other CNS or spinal (non-spinal cord) metastases and the primary tumor/non-CNS metastases are common. The prevalence of other CNS or spinal (non-spinal cord) metastases in those with multiple intramedullary spinal cord metastases is especially high.

Retrospective review of rapid pediatric brain MR imaging at an academic institution including practice trends and factors affecting scan times

BACKGROUND AND PURPOSE

In an effort to reduce radiation exposure in children requiring regular follow up for shunted hydrocephalus, our institution implemented a rapid brain MR imaging protocol. The purpose of this study was to review an academic practice experience with pediatric rapid brain MR imaging without patient sedation in the evaluation of hydrocephalus and a limited group of other conditions.

MATERIALS AND METHODS

We retrospectively analyzed limited-sequence, rapid brain MR imaging scans performed in nonsedated patients younger than 14 years between April 2009 and December 2011. So-called failed examinations were determined by consensus of 2 authors as insufficiently diagnostic for evaluation of ventricular size. CT and MR imaging quarterly volumes for hydrocephalus-related indications were determined from 2005-2012. Multivariable logistic regression analysis was performed to elucidate factors potentially affecting scan durations including examination indication and patient age, sex, inpatient status, and clinical conditions.

RESULTS

A total of 398 examinations were performed on 168 patients (103 boys, 65 girls; median age, 13 months). None were deemed to be failed examinations. Median scan duration was 4.43 minutes (interquartile range, 4.42 minutes-5.88 minutes; SD, 2.42 minutes). Examination indication of altered mental status was the only factor associated with increased scan duration (+1.77 minutes; P = .0021). Hydrocephalus-related imaging volumes approximately doubled in the 7 years reviewed, but rapid MR imaging introduced in 2009 is quickly replacing CT scanning for these indications, accounting for nearly 7 of every 8 examinations at the end of the study period.

CONCLUSIONS

In every case of initial work-up and follow-up, rapid brain MR imaging effectively evaluated ventricular size and/or intracranial fluid and represents a viable alternative to CT scanning, irrespective of a child's age or clinical condition. For this indication and patient group, MR imaging is now the predominant imaging method in our practice.

Position-related variability of CSF opening pressure measurements

BACKGROUND AND PURPOSE

Normative data for CSF OP have previously been established with patients in the LD position. During fluoroscopically guided LP procedures, radiologists frequently obtain these OP measurements with patients prone. In this prospective study, our goal was to determine the variability of OP measurements as a function of patient positioning and to assess whether there is a relationship with patient BMI.

MATERIALS AND METHODS

Consecutive patients reporting for fluoroscopically guided LP or myelography were enrolled. OP was measured with the patient in 3 positions, with the order of the technique randomized: prone with table flat, prone with table tilted until the hub of the needle was at the level of the right atrium, and LD with the needle hub at the level of the spinal canal. The BMI of each patient was calculated. The Wilcoxon signed-rank test and linear regression analysis with bivariate fit of difference were used for analysis.

RESULTS

OP measurements with the patient in the prone position were significantly elevated compared with those in the LD position, with mean differences of 2.7 (P<.001) and 1.6 cm H2O, (P=.017) for prone flat and prone tilted, respectively. There was no significant difference in OP measurements for the prone flat versus prone tilted positions (P=.20). There was no correlation between BMI and observed differences (LD-flat: R2=0.00028; LD-tilt: R2=0.00038; prone-tilt: R2=0.00000020).

CONCLUSIONS

Measuring OP with the patient in the prone position may result in overestimation of CSF pressure. Table tilt did not significantly impact mean prone OP. Radiologists should specify exact patient positioning when reporting OP measurements.

Rim and flame signs: postgadolinium MRI findings specific for non-CNS intramedullary spinal cord metastases

BACKGROUND AND PURPOSE

No highly specific MR imaging features distinguishing ISCMs from primary cord masses have been described. Our purpose was to retrospectively compare peripheral enhancement features on postgadolinium MR imaging of ISCMs with primary intramedullary cord masses.

MATERIALS AND METHODS

A consecutive group of patients with firmly diagnosed ISCM (45 patients with 64 ISCMs) and a comparison group with consecutive pathologically proved primary intramedullary spinal cord masses (64 patients with 64 primary spinal cord masses: ependymoma, astrocytoma, hemangioblastoma, ganglioglioma, and cavernous malformation) were included. MR images were evaluated for 2 specific signs on postgadolinium images: a "rim" sign (more intense thin rim of peripheral enhancement around an enhancing lesion) and "flame" sign (ill-defined flame-shaped region of enhancement at the superior/inferior lesion margins). The frequency of rim and/or flame signs in ISCMs and primary cord masses was compared (χ2 test). For ISCMs, the maximal dimension of the enhancing lesion was correlated with the presence of rim or flame signs (t test).

RESULTS

Rim and flame signs, alone and in combination, were seen more frequently in ISCMs than in primary cord masses (P<.0001 for each). Specificity and sensitivity, respectively, for diagnosing ISCMs among spinal cord masses on a per-patient basis were the following: rim sign, 97%, 47%; flame sign, 97%, 40%; at least 1 sign, 94%, 60%; and both signs concurrently, 100%, 27%. In the ISCM group, the presence of either a rim or flame sign correlated with a larger measured maximum enhancing lesion size (P=.0065 and P=.0012, respectively).

CONCLUSIONS

The rim and flame signs are common in and specific for ISCM and are rare in primary spinal cord masses.

Irrigation nose: CT findings of paranasal sinus exostoses

We report the case of a 57-year-old male who presented with recurrent sinus infections and frequent nasal irrigation. He was found at nasal endoscopy to have multiple outgrowths along his ethmoid and maxillary sinuses. Computed tomography (CT) showed multiple bony exostoses along these sinuses. We report the imaging findings of exostoses associated with sinonasal irrigation.

When should I do dynamic CT myelography? Predicting fast spinal CSF leaks in patients with spontaneous intracranial hypotension

BACKGROUND AND PURPOSE

Some patients with SIH have fast CSF leaks requiring dynamic CTM for localization; however, patients generally undergo conventional CTM before a dynamic study. Our aim was to determine whether findings on head MR imaging, spine MR imaging, or opening pressure measurements can predict fast spinal CSF leaks.

MATERIALS AND METHODS

A retrospective review was performed on 151 consecutive patients referred for CTM to evaluate for spinal CSF leak. Head MR imaging was evaluated for diffuse dural enhancement and "brain sag," and spine MR imaging for presence of an extradural fluid collection. The opening pressure was recorded. The CTM was scored as no leak, slow leak localized on conventional CTM, or fast leak that required dynamic CTM.

RESULTS

Fast CSF leaks were identified in 32 (21%), slow leaks in 36 (24%), and no leak in 83 (55%) of 151 patients on initial CTM. There was significant association between spinal extra-arachnoid fluid on MR imaging and the presence of a fast leak (sensitivity 85%, specificity 79%, P < .0001). There was not significant association between fast leak and findings on head MR imaging (P = .27) or opening pressure (P = .30).

CONCLUSIONS

If all patients with spinal extra-arachnoid CSF on MR imaging had been sent directly to dynamic CTM, repeat myelography would have been avoided in most patients with fast leaks (23 of 27; 85%). However, a minority of patients with slow or no leaks would have been converted from conventional to dynamic CTM (16 of 77; 21%). Spinal MR imaging is helpful in premyelographic evaluation of SIH.

The role of MR myelography with intrathecal gadolinium in localization of spinal CSF leaks in patients with spontaneous intracranial hypotension

BACKGROUND AND PURPOSE

Localization of spinal CSF leaks in CSF hypovolemia is critical in directing focal therapy. In this retrospective review, our aim was to determine whether GdM was helpful in confirming and localizing spinal CSF leaks in patients in whom no leak was identified on a prior CTM.

MATERIALS AND METHODS

Forty-one symptomatic patients with clinical suspicion of SIH were referred for GdM after undergoing at least 1 CTM between February 2002 and August 2010. A retrospective review of the imaging and electronic medical records was performed on each patient.

RESULTS

In 17 of the 41 patients (41%), GdM was performed for follow-up of a previously documented leak at CTM. In the remaining 24 patients (59%), in whom GdM was performed for a suspected CSF leak, which was not identified on CTM, GdM localized the CSF leak in 5 of 24 patients (21%). In 1 of these 5 patients, GdM detected the site of leak despite negative findings on brain MR imaging, spine MR imaging, and CTM of the entire spine. Sixteen of 17 patients with previously identified leaks underwent interval treatment, and leaks were again identified in 12 of 17 (71%).

CONCLUSIONS

GdM is a useful technique in the highly select group of patients who have debilitating symptoms of SIH, a high clinical index of suspicion of spinal CSF leak, and no demonstrated leak on conventional CTM. Intrathecal injection of gadolinium contrast remains an off-label use and should be reserved for those patients who fail conventional CTM.

The utility of diffusion-weighted imaging for cholesteatoma evaluation

DWI is a useful technique for the evaluation of cholesteatomas. It can be used to detect them when the physical examination is difficult and CT findings are equivocal, and it is especially useful in the evaluation of recurrent cholesteatoma. Initial DWI techniques only detected larger cholesteatomas, >5 mm, due to limitations of section thickness and prominent skull base artifacts. Newer techniques allow detection of smaller lesions and may be sufficient to replace second-look surgery in patients with prior cholesteatoma resection.

Diffusion-weighted imaging for cholesteatoma evaluation

Computed tomography (CT) has long been considered the optimal imaging technique for the detection of cholesteatomas. However, this modality often lacks specificity, particularly in patients with an absence of definite bony erosion or a history of surgical excision. Several investigators have proposed magnetic resonance imaging with diffusion-weighted imaging (DWI) as a means of diagnosing the presence and extent of cholesteatomas, particularly when CT results are equivocal. The rationale for the use of DWI is that cholesteatomas demonstrate restricted diffusion and granulation tissue does not. In this retrospective study, we review our experience with 12 patients who had undergone DWI for evaluation of a mass in the middle ear, mastoid, or petrous apex. Ten of these patients had previously undergone middle ear surgery, 8 for cholesteatoma resection. On DWI, 9 patients demonstrated restricted diffusion. Of these, 8 patients underwent surgical resection, and all were found to have had a cholesteatoma. Of the 3 patients who had not demonstrated restricted diffusion on DWI, 2 did not undergo surgery and the other was found to have only chronic inflammation at surgery. Based on our limited experience, we believe that DWI can be useful in confirming the diagnosis of cholesteatoma. Moreover, it may alter patient management, particularly in patients whose previous tympanoplasty/mastoidectomy does not allow for an adequate clinical inspection of the middle ear cavity.

Hepatitis C-associated osteosclerosis: a case report

A 38-year-old man presented for evaluation of severe pain in his lower limbs of 16 months' duration. Radiographs showed diffuse bony sclerosis involving the axial and appendicular skeleton with marked cortical thickening in the diaphyseal regions of the long bones. Iliac crest biopsy revealed abundant sclerotic bone. The patient was diagnosed with hepatitis C secondary to intravenous drug use 20 years earlier, and the bony findings and clinical symptoms attributed to hepatitis C-associated osteosclerosis (HCAO). Little is known about the natural history of this disease; however, we discuss the patient's clinical course over 15 years.

Pattern of T2 hypointensity associated with ring-enhancing brain lesions can help to differentiate pathology

Ring-enhancing lesions seen on MR images can occur with a variety of etiologies. Some ring-enhancing lesions have hypointense rims peripherally on T2-weighted MR images. In this study, we examined whether T2 hypointense rims were associated with specific pathologies. A search for ring-enhancing lesions on MR images obtained from 1996 to 2004 was performed, and revealed 221 patients with MRI findings of ring enhancement. The pattern of T2 hypointensity (arc or rim) corresponding with ring enhancement was recorded. In addition, we analyzed other imaging characteristics, including signal on diffusion-weighted images, central homogeneity on T2 and multiplicity of lesions. We then reviewed clinical data on the patients to ascertain the diagnosis for each examination. The most common associated pathologies in our study were gliomas (40%), metastases (30%), abscesses (8%) and multiple sclerosis (MS; 6%). Hypointense borders on T2-weighted images were present in 67% of lesions in the form of a rim in 40% and an arc in 60%. Abscesses had the highest percentage of hypointense rims. Metastases and gliomas more commonly had arcs, and MS lesions were divided between rims and arcs. Abscesses and MS lesions were more commonly homogeneous centrally, compared to gliomas and metastases. Additionally, abscesses were more often bright on diffusion imaging than the other pathologies. As expected, abscesses and MS lesions were usually multiple, whereas metastases were typically multiple in approximately 50% of the patients; gliomas were generally solitary. Trends in T2 hypointensity may aid in distinguishing among etiologies of ring-enhancing lesions, although there is overlap between the MR appearance of these various pathologies.

Thyroid acropachy: report of 40 patients treated at a single institution in a 26-year period

Thyroid acropachy is an extreme manifestation of autoimmune thyroid disease. It presents with digital clubbing, swelling of digits and toes, and periosteal reaction of extremity bones. It is almost always associated with ophthalmopathy and thyroid dermopathy. During a 26-yr period at our institution, of 178 patients with thyroid dermopathy, 40 had acropachy. Clubbing associated with thyroid dermopathy (pretibial myxedema) was seen in 35 patients. Clubbing usually was not a patient complaint and was noted only by clinical observers. Four of eight patients with hand and extremity radiographs had periosteal reaction. Seven had associated extremity and joint pain; this pain was absent at long-term follow-up. Half of the patients required systemic corticosteroid therapy, 53% required transantral or transfrontal orbital decompression for severe ophthalmopathy, and 18% had the elephantiasic form of dermopathy. Cigarette-smoking rates were 81% for women and 75% for men (mean, 28 pack-years). All 13 patients who had thyroid-stimulating Ig measurement had high titers. Long-term follow-up (median, 12.5 yr) revealed that acropachy was not a complaint in follow-up visits or questionnaires. The data suggest that thyroid acropachy is an indicator of severity of ophthalmopathy and dermopathy. It is a source of clinical concern only if dermopathy is persistent and severe.

Ventilation tube removal: does treatment affect perforation closure?

OBJECTIVE

The study goal was to determine whether treatment of the tympanic membrane at the time of ventilation tube (VT) removal affects closure of the perforation.

STUDY DESIGN

We conducted a retrospective chart review and telephone follow-up of children who underwent VT removal from 1995 through 1998.

RESULTS

Among 109 patients (162 ears; 58% male), the mean age at VT removal was 6.7 years. Most VTs (59%) were T-tubes, and most (91%) were removed because of prolonged retention (mean 2.3 years). After VT removal, 111 ears (69%) received treatment, most commonly (44%) with 25% trichloroacetic acid (TCA). At the latest follow-up, 151 of the ears (93%) had healed without additional treatment. Treatment failure occurred more frequently in ears not initially treated with TCA (TCA 3% failure, other treatment 13%, no treatment 8%) and in ears with VTs removed because of otorrhea.

CONCLUSIONS

Most perforations healed. TCA may promote closure, but a large randomized clinical trial is needed to eliminate physician bias.

Dermopathy of Graves' disease (pretibial myxedema): long-term outcome

Little is known about the long-term outcome of patients with thyroid dermopathy, an extrathyroidal manifestation of Graves' disease. Also, it is not known to what degree treatment promotes remission of the lesions. The present report supplies information on the natural course of mild, untreated and severe, treated thyroid dermopathy. In this study, we report on the outcomes of 178 patients seen at our institution between January 1969 and November 1995 with thyroid dermopathy who were followed up for an average of 7.9 yr. Nonpitting edema was the most prevalent form of dermopathy (43.3%), and the pretibial area was the region most commonly involved (99.4%). The majority of patients with dermopathy had ophthalmopathy (97.0%). Topical corticosteroids were the most commonly used treatment (53.9%). Patients with milder forms of dermopathy (40.4%) did not receive any therapy for dermopathy. Twenty-six percent of the patients experienced complete remission, 24.2% had moderate improvement (partial remission), and 50.0% had no or minimal improvement of their dermopathy at last follow-up. Patients who did not receive therapy experienced a significantly (P = 0.03) higher rate of complete remission (34.7%) than those who received local therapy (18.7%), although the combined complete and partial remission rates were not significantly different for the treated and untreated groups (P = 0.3). However, the treated and untreated groups were not comparable because our practice is to use therapy for more extensive and severe cases. All five cases of elephantiasis were in the treatment group and were less likely to have remission because of the severity of their skin condition. Patients receiving treatment were more likely to have dermatologic consultation and histologic diagnosis (P < 0.001). The beneficial effect of topical corticosteroid therapy on long-term remission rates remains to be determined.

Pseudotumor of infancy and congenital muscular torticollis: 170 cases

OBJECTIVES

To review pseudotumor of infancy (POI) and congenital muscular torticollis (CMT) and to suggest an algorithm for treatment.

STUDY DESIGN

Retrospective review of cases from 1962 to 1998 at a tertiary care center.

METHODS

Patients included in this study were 81 boys and 89 girls who had a diagnosis of POI (n = 38) or CMT (n = 132) before 24 months of age.

RESULTS

For all patients, the mean age at diagnosis was 4 months; 54.1% had the left side of the neck affected, over 90% had a head tilt, and 2.4% had feeding difficulty as a result of the disorder. Plagiocephaly was present in 39.5% of patients with POI and 63.6% of patients with CMT; a neck mass, in 63.2% and 18.2%, respectively; and facial asymmetry, in 7.9% and 15.9%, respectively. All patients had a complete physical examination; 54.1% had plain cervical radiography, 4.1%, computed tomography, and 2.9%, ultrasonography. Passive range of motion was the initial treatment recommended for 65.3% of patients. Conservative treatment failed for 16 patients; subsequently, they had surgical treatment. Follow-up data were available for 159 patients; 85.5% experienced total resolution and 14.5% experienced subtotal resolution or long-term abnormality.

CONCLUSIONS

Children diagnosed with POI or CMT should be treated and observed for at least 12 months or until symptoms resolve. If symptoms persist 1 year after diagnosis despite conservative therapy, surgical treatment should be considered. The majority of children with POI or CMT experience total resolution of symptoms.

Effects of oral propafenone on defibrillation and pacing thresholds in patients receiving implantable cardioverter-defibrillators. Propafenone Defibrillation Threshold Investigators

OBJECTIVES

The effects of propafenone, a predominantly class IC antiarrhythmic drug, on defibrillation and pacing thresholds were evaluated in patients undergoing cardioverter-defibrillator implantation.

BACKGROUND

Previous studies have shown that the class IC agents encainide and flecainide may increase the energy requirements for pacing and defibrillation. Animal studies with propafenone have shown inconsistent results regarding its effect on defibrillation energy requirements. This report investigated the effects of propafenone on defibrillation and pacing thresholds in humans.

METHODS

After cardioverter-defibrillator implantation, 47 patients were enrolled in a double-blind, three-way parallel, randomized trial of 450 mg/day (Group 1) or 675 mg/day (Group 2) of oral propafenone or placebo (Group 3) for 3 to 7 days. Predischarge defibrillation and pacing thresholds after treatment were compared with baseline thresholds obtained at implantation.

RESULTS

There was no statistically significant difference between implantation and predischarge defibrillation thresholds in the three groups (Group 1: [mean +/- SE] 11.0 +/- 1.3 vs. 12.1 +/- 1.5 J; Group 2: 11.5 +/- 1.1 vs. 13.6 +/- 1.3 J; Group 3: 12.5 +/- 1.2 vs. 13.3 +/- 1.6 J), and no significant difference between treatment groups was found with a 0.86 power to detect a 5-J difference between groups. Paired pulse width pacing thresholds at 2.8 V were compared in 14 patients. A small increase of 0.02 ms was noted at predischarge testing in patients treated with propafenone and placebo.

CONCLUSIONS

Short-term oral propafenone (450 and 675 mg/day) does not significantly affect defibrillation or pacing thresholds. Concomitant use of propafenone in patients with implantable cardioverter-defibrillators with recurrent ventricular or atrial tachyarrhythmias should not interfere with proper device function.

Production of IL2 and IL3 in syngeneic mixed lymphocyte reactions of BALB/c mice are elevated during a period of moderate dietary protein deficiency

The mixed lymphocyte reaction (MLR) is a model of T cell responsiveness to antigenic peptides complexed with major histocompatibility (MHC) proteins on antigen presenting cells (APC). Since dietary protein deficiencies alter T cell development, syngeneic and allogeneic MLR were investigated in mice fed a low protein 4% casein (4Ca) or control 20% casein (20Ca) diet. Proliferation of splenic lymphocyte populations from BALB/c mice fed 4Ca was increased during syngeneic and allogeneic MLR compared with lymphocytes from mice fed 20Ca. Increased proliferation was accompanied by significantly higher production of IL2 and IL3 during syngeneic, but not allogeneic MLR. To determine the influence of autologous B cells on IL2 and IL3 production during MLR, lymphocyte populations of mice fed 4Ca or 20Ca were depleted of B cells. Splenic lymphocyte populations of mice fed 4Ca that were depleted of B cells did not exhibit increased IL2 or IL3 production during syngeneic or allogeneic MLR. Splenic APc of mice given 4Ca caused greater proliferation during MLR. However, APC of 4Ca mice did not cause greater IL2 or IL3 production. Similarly neither IgM-B cells nor macrophage from mice fed 4Ca induced elevated IL2 or IL3 production during syngeneic or allogeneic MLR. A dichotomy appeared in that 4Ca-APC were able to induce higher T cell proliferation but not cytokine production compared with 20Ca-APC. The enhancement of T cell responsiveness to Class II MHC determinants on APC during moderate protein deficiency appears to require both T and B cells from mice fed the deficient diet.

Experience with the use of coronary autoperfusion catheter during complicated angioplasty

Between February and July of 1989, 22 patients underwent the use of the Stack autoperfusion catheter following acute occlusion or obstructive dissection during coronary angioplasty; in 20 cases conventional balloon was used in an attempt to correct the angiographic appearance followed by the use of Stack catheter when results were sub-optimal. Only 1 patient (4.5%) required surgical revascularization. Although our study is not prospective or randomized, our observations suggest a significant impact in decreasing the need for emergency surgical revascularization after complicated coronary angioplasty with the use of this approach.

Atenolol and chlorthalidone therapy for hypertension: a double-blind comparison

In a randomized, double-blind, parallel-group study of 31 patients with mild to moderate hypertension, we compared a placebo regimen with a regimen of atenolol and chlorthalidone (Tenoretic). The study, which lasted seven weeks, began with a single-blind two-week placebo lead-in period, followed by a four-week double-blind treatment phase, and concluded with a one-week single-blind placebo washout period. Of 24 patients included in the analysis of efficacy, seven received one Tenoretic 50 tablet per day (atenolol, 50 mg; chlorthalidone, 25 mg), nine received one Tenoretic 100 tablet per day (atenolol, 100 mg; chlorthalidone, 25 mg), and eight received placebo. Supine systolic/diastolic blood pressure (mean +/- SD) decreased from 154 +/- 15.2/102 +/- 4.6 mm Hg during the baseline period to 128 +/- 8.5/85 +/- 4.0 mm Hg during treatment in the group receiving Tenoretic 100, from 153 +/- 12.6/104 +/- 5.4 mm Hg to 137 +/- 4.5/91 +/- 4.4 mm Hg in the group receiving Tenoretic 50, and from 150 +/- 11.9/101 +/- 1.6 mm Hg to 145 +/- 11.6/93 +/- 5.1 mm Hg in the group receiving placebo. Reductions in systolic and diastolic blood pressures in the active treatment groups were significantly greater than the pressure reductions in the group receiving placebo (P less than .05 to .1). The combination of atenolol and chlorthalidone was well tolerated, and in no case was treatment discontinued because of side effects. This study showed that one tablet per day of either Tenoretic 50 or Tenoretic 100 is effective and well tolerated in the treatment of mild to moderate hypertension.

A temporary external DDD pacing unit

A device for temporary external DDD pacing was developed using a modified permanent pulse generator, and temporary atrial and ventricular electrode catheters were inserted pervenously. The atrial lead was a J type and the ventricular lead had a remote anode in the superior vena cava. With a special clamp and appropriate connectors the permanent DDD pulse generator provided unipolar external DDD pacing. The device was evaluated in 13 patients to control bradyarrhythmias or for overdrive pacing in an attempt to control tachyarrhythmias. Nine patients were ambulatory; all had continuous electrocardiographic monitoring. The device was used for 1 to 12 days (mean 4.9). Eight patients benefited from temporary DDD pacing and 7 had permanent DDD pacemakers implanted. In 1 patient, atrial fibrillation developed, 2 patients had brief episodes of ventricular lead displacement and another required reprogramming because of loss of ventricular capture. Results suggest that the device is applicable for a clinical trial of DDD pacing before possible permanent implantation when attempting to improve cardiac output or control arrhythmias.

Clinical evaluation of a new temporary atrial pacing catheter: results in 100 patients

Absence of a temporary atrial electrode that is stable and easily positioned has limited the use of atrial pacing in the hospital setting. A novel electrode involving a performed, 6F "J"-shaped catheter with a 10F anodal sphere and proximal fixed orienting wings 28 cm from the anodal tip was constructed. This design facilitated percutaneous insertion into the subclavian vein and positioning without fluoroscopy. Over a 15-month period, five physicians used the device in 100 patients for control of bradycardia in 56, overdrive suppression of atrial or ventricular tachyarrhythmias in 29, conversion and control of paroxysmal atrial tachycardia in seven, and temporary atrial-ventricular sequential pacing in eight patients with complete heart block. In 75 patients the electrode was inserted at the bedside without the benefit of fluoroscopy. Average insertion time was 2.5 minutes, initial thresholds were good, and lead stability evaluated by x-ray films and ECG recordings was excellent. The duration of pacing with the lead was 4.3 days (mean) and ranged from 1 to 23 days, with episodes of capture failure in only seven cases. Two of these cases were readily corrected by repositioning. This new electrode system could be rapidly inserted with excellent stability and reliability for days. Its ease of use could expand the role of temporary atrial pacing.

Pacemaker-mediated tachycardias: a rapid bedside technique for induction and observation

The DDD pacemaker allows sensing and pacing in both chambers and can, therefore, maintain atrioventricular synchrony. However, this pacemaker creates an additional anterograde conduction system between the atrium and ventricle and, in the presence of ventriculoatrial (VA) conduction, the possibility of pacemaker-mediated tachycardia exists. A simple bedside technique that does not require catheterization or expensive equipment was used to detect VA conduction. Just after DDD pacer implantation, an attempt was made to detect VA conduction in 31 patients. Ambulatory monitoring (Holter) was done for 24 hours after implantation and at 2 to 4 and 6 to 8 weeks after implantation to detect pacemaker-mediated tachycardia. Attempts to induce pacemaker-mediated tachycardia were made using a special programmable external stimulator at follow-up after implantation. It was found that (1) all the 17 patients with detectable VA conduction had pacemaker-mediated tachycardia when the atrial refractory period was less than the VA conduction time, (2) pacemaker-mediated tachycardias were not inducible or detected spontaneously when atrial refractory period was equal to or greater than VA conduction time + 50 ms, (3) VA conduction was not detectable in 9 of the 17 patients at a later visit. Six of these 9 received antiarrhythmic therapy or had developed congestive heart failure. VA conduction has important implications in patients with DDD pacemakers and can be readily evaluated at the bedside.

The direct negative chronotropic action of prazosin on the canine sinus node

The direct and indirect chronotropic effects of prazosin were studied in 22 anesthetized dogs using the technique of selective perfusion of the sinus node. Concentrations of 1, 10, 50 and 100 micrograms/ml of prazosin produced cumulative, dose-related reductions in mean sinus rat of 4 +/- 2; 10 +/- 6; 15 +/- 9 and 27 +/- 15 beats/min, respectively (P less than .0001). Intranodal prazosin did not significantly alter the positive chronotropic sinus node response to norepinephrine (0.05 and 0.1 micrograms/ml) administered via the same route. Sinus rate increases during stimulus frequency response curves after right stellate stimulation were not influenced by prior administration of prazosin. Sinus bradycardia elicited by submaximal vagal stimulation also was not affected by intranodal prazosin.l In six reserpinized dogs, methoxamine (10 and 25 micrograms/ml) injected into the sinus node artery caused a sinus rate increase of 10 4/- 2 and 14 +/- 3 beats/min (P less than .001). Intranodal prazosin (50 micrograms/ml) prevented this effect. Taken together, these results indicate that prazosin exerts a direct negative chronotropic action on the canine sinus node and that this effect is at least in part mediated through interference with alpha-1 receptors located in or near the sinus node. Prazosin has little or no effect on the presynaptic alpha-2 receptors nor does it interfere with the cholinergic mechanism in the sinus node.

Limited exercise testing soon after myocardial infarction. Correlation with early coronary and left ventricular angiography

Forty-eight patients within 3 weeks of myocardial infarction underwent both limited treadmill graded exercise testing and coronary and left ventricular angiography. Nineteen (90%) of 21 patients with positive exercise tests (greater than or equal to 1 mm ST depression, angina, or both) had multivessel coronary artery disease. In the 27 patients with negative exercise test results, 15 (55%) had multivessel disease, 11 (41%) had single-vessel disease, and one (4%) had no coronary stenosis. Exercise-induced ST segment elevation occurred in 24 patients and predicted a significantly lower ejection fraction and higher angiographic abnormally contracting segment size. Patients experiencing angina during or after exercise had a significantly shorter 2-year survival (54% +/- 21%) than patients without exercise-induced angina (97% +/- 3%) (p less than 0.03). Thus limited exercise testing postinfarction is useful in evaluating the presence of multivessel coronary artery disease and left ventricular dysfunction and predicting long-term survival.