Detection of Drugs in Postmortem Specimens of Blood, Vitreous Humor and Bone Marrow Aspirate.

In case of basic biological materials (blood, urine, vitreous humor) being unavailable, bone marrow can be used for toxicological tests. The aim of the study was to assess the concentration of various xenobiotics in the bone marrow, as well as in the blood and the vitreous humor. The analysis was performed in the biological material originating from the autopsy (n = 120), using the LC-MS method and with liquid/liquid extraction at pH = 9. As many as 46 different xenobiotics were detected in the biological material, strong correlations between the concentration of a given xenobiotic in blood and bone marrow, as well as in the vitreous humor and bone marrow, were noted for most of them, with the exception of diazepam and 7-aminoclonazepam. The obtained results indicate the possibility of using bone marrow to determine the concentration of numerous xenobiotics in the situation of basic biological materials being unavailable, as well as using the results obtained in the future to better understand the pharmacokinetic processes and the effect of postmortem redistribution on medication and drug concentrations in the body of a deceased person.

Dissociative ionization dynamics of dielectric gas C3F7CN.

Fluoronitrile C3F7CN is a promising candidate for the replacement of SF6 dielectric gas in high-voltage insulation. We present a combined experimental and theoretical study on its ionization dynamics probed in the 0-100 eV energy range. We exploited the total ion collection technique to determine the absolute ionization cross section, mass spectrometry to determine the fragment branching ratios and ab initio nonadiabatic molecular dynamics to simulate the ionization process. The latter two approaches showed the dominating presence of the CF3+ cation over the whole electron energy range. The Binary-Encounter-Bethe (BEB) approximation reproduces experimental cross sections very well and reveals that the ionization from a surprisingly large number of orbitals contributes almost equally to the processes. We show that the initially populated cation excited states undergo an ultrafast internal conversion to the ground state where the dissociation into a single decay channel takes place. Implications for the use of C3F7CN as an insulating material are discussed.

Should anastomotic assessment with flexible sigmoidoscopy be routine following laparoscopic restorative left colorectal resection?

AIM: The aim of the study was to evaluate the value of routine intra-operative flexible sigmoidoscopy (IOFS) for left-sided anastomotic integrity and to determine the safest step after a positive leak test. METHOD: All consecutive patients undergoing left-sided colorectal resections for benign and malignant disease between August 2005 and April 2011 were included. Data regarding procedure, type of anastomosis and outcomes of IOFS were collected. A positive intra-operative leak test resulted in redoing the anastomosis and repeating the leak test. RESULTS: A total of 415 consecutive patients underwent hand-assisted laparoscopic colorectal resection with a colorectal/ileoanal anastomosis. All patients underwent IOFS. Seventeen patients had abnormality on IOFS. Fifteen patients had a positive air leak test. One patient had anastomotic bleeding. There was one stapler misfiring. Fourteen anastomoses were redone without diversion. One patient required diversion to protect the ileoanal anastomosis and another had already been diverted. Minor bleeding from the staple line in one patient resolved without intervention; however, he had a postoperative anastomotic leak needing surgical intervention. None of the patients who had a takedown and refashioning of the anastomosis following a positive leak on IOFS had postoperative anastomotic leakage or bleeding. Our overall anastomotic leak rate was 2.1%. CONCLUSIONS: Intra-operative flexible sigmoidoscopy for restorative colorectal resection is safe and reliable and should be performed routinely to assess anastomotic integrity and bleeding. Refashioning the anastomosis after formal takedown would obviate the risk of leakage and is our recommended method of managing intra-operative leaks.

Is hybrid robotic laparoscopic assistance the ideal approach for restorative rectal cancer dissection?

AIM: While the use of robotic assistance in the management of rectal cancer has gradually increased in popularity over the years, the optimal technique is still under debate. The authors' preferred technique is a robotic low anterior resection that requires a hybrid approach with laparoscopic hand-assisted mobilization of the left colon and robotic assistance for rectal dissection. The aim of this study was to determine the efficacy of this approach as it relates to intra-operative and short-term outcomes. METHOD: Between August 2005 and July 2011, consecutive patients undergoing rectal dissection for cancer via the hybrid robotic technique were included in our study. Demographics, margin positivity, intra-operative and short-term outcomes were evaluated. RESULTS: The preferred approach was performed in 77 patients with rectal adenocarcinoma. Of these, 68 underwent low anterior resection and nine had a coloanal pull-through procedure (mean age 60.1 years; mean body mass index 28.0 kg/m(2) ; mean operative time 327 min; conversion rate 3.9%). Three patients (3.9%) had positive resection margins (one circumferential, two distal). Five patients had an anastomotic leak (6.4%). No robot-specific complications were observed. CONCLUSION: The hybrid approach involving hand-assisted left colon mobilization and robotic rectal dissection is a safe and feasible technique for minimally invasive low anterior resection. This approach can be considered an viable option for surgeons new to robotic rectal dissection.

"Giant" arachnoid granulations just like CSF?: NOT!!

"Giant" AGs (>1 cm) are uncommon and can be misdiagnosed as venous sinus pathology such as a neoplasm or thrombosis. Seventeen patients with a total of 19 venous sinus AGs of >1 cm were collected from contributing authors. MR imaging was available for all AGs; CT, for 5/19; and DSA, for 7/19. Intra-AG fluid was compared with CSF in subarachnoid spaces. Nonfluid AG tissue was compared with gray matter. Diagnosis was based on imaging findings. Fluid within giant AGs did not follow CSF signal intensity on at least 1 MR image in nearly 80% (15/19) of AGs. Nine of these 15 AGs had CSF-incongruent signal intensity on ≥2 MR images. CSF-incongruent signal intensity was seen in 8/8 AGs on FLAIR, 7/10 on precontrast T1WI, 13/19 on T2WI, and 8/14 on contrast-enhanced T1WI. Nonfluid signal intensity was present in 18/19 AGs and varied from absent/hypointense (intra-AG flow voids) to gray matter isointense (stromal tissue).

Emerging impact of CTA/perfusion CT on acute stroke thrombolysis in a community hospital.

Our objective was to retrospectively review the emerging role of CT, CTA, and perfusion CT (pCT) in the hyperacute stroke population of a community hospital. We reviewed 50 consecutive patients' records and imaging studies, who were treated with thrombolytic therapy within 6 h of symptom onset. Multidetector CT, CTA, and pCT studies were evaluated. Subsequent CT, magnetic resonance, or angiographic studies when available were correlated. Patients' clinical data at admission and outcomes at discharge were evaluated. Complications were tabulated. Of the 50 patients treated with thrombolytics, 37 had CT/CTA/pCT, the others non-contrast CT only. CT blood volume defect was present in a total of 14 patients, presaging permanent infarct in all. Arterial clot was seen in 28/37 CTAs (carotid "T" 6, MCA 16, vertebrobasilar 6). Viable penumbra was shown in 20/37; rescued penumbra was depicted after treatment in 14. 39 patients were treated with intravenous, nine with intra-arterial, two with both forms of thrombolysis. Modified Rankin score showed clinical improvement in 58%, three patients had complete recovery. Subsequent bleed was shown in two (4%), symptomatic in one (2%). Two patients died. Our experience suggests advanced CT is more sensitive to ischemia than routine CT, that salvageable penumbra can be identified, and that triage of patients with acute stroke for thrombolysis with CT/CTA/pCT is more robust than routine CT alone, and may improve outcomes in the community hospital setting.

Brown-Séquard syndrome secondary to spontaneous bleed from postradiation cavernous angiomas.

SUMMARY: The spontaneous occurrence of acute Brown-Séquard syndrome is an extremely rare event, with most reported cases being secondary to spontaneous epidural hematomas and spinal cord ischemia. We report a rare case of Brown-Séquard syndrome from spontaneous intraspinal hemorrhage in a patient with multiple cavernous angiomas in the spinal cord secondary to craniospinal radiation in childhood. Postulated mechanisms leading to the condition include postradiation molecular changes and venous occlusion.

Central neurocytoma: case report of an 81-year-old and histopathologic findings.

Central Neurocytomas are rare and usually benign tumors found primarily in the lateral ventricles of the brain. Central Neurocytomas are composed of uniform round cells exhibiting neuronal differentiation and are found almost exclusively in young adults between 15 and 60 years of age. The authors report the case of an 81-year-old man with a history of severe psychosis and depression, who presented with progressive confusion and ataxia likely unrelated to a central neurocytoma of his right lateral ventricle. The patient underwent a stereotactic biopsy of the lesion, followed by Gamma Knife radiosurgery. Histopathology showed immunohistological staining for synaptophysin, neuron specific enolase (NSE) and neuronal nuclear antigen (NeuN). A review of published literature on central neurocytomas revealed that this tumor occurs most frequently in young adults with a median age between 25 and 30 years. This pathology has never been reported in patients over the age of 80. Gamma Knife radiosurgery was successful in decreasing the tumor volume by 20% at the four month follow-up, but the fact that the patient died of unrelated occurrences in the elderly cannot be ruled out. Patients with central neurocytomas commonly present with obstructive hydrocephalus and immediate treatment may be necessary to tide over urgent situations.

Fluid-attenuated inversion recovery (FLAIR): clinical prospectus of current and future applications.

A relative weakness of the traditional spin-echo technique, and particularly of the newer "FAST" or "TURBO" spin-echo sequences, has been diminished conspicuousness of lesions affecting the peripheral cortical mantle or those located in the periventricular region. This is a consequence of partial volume effects and high cerebrospinal fluid (CSF) signal adjacent to pathologic regions. Fluid-attenuated inversion recovery (FLAIR) is a magnetic resonance imaging (MRI) sequence that produces strong T2 weighting, suppresses the CSF signal, and minimizes contrast between gray matter and white matter. This effect produces images with significantly increased lesion-to-background CSF contrast and enhances the visibility of lesions as well as their detectability, particularly in the peripheral subcortical and periventricular regions. Applications are evolving, though preliminary reports highlight the superiority of FLAIR in the evaluation of infarction, multiple sclerosis, metastatic disease, tuberous sclerosis, and, possibly, subarachnoid hemorrhage. Early reports also address the application of FLAIR to imaging of the spinal cord. Modified versions of FLAIR are currently being developed; these modifications will further shorten acquisition times and eliminate pulsation artifacts. FLAIR may ultimately supplant conventional spin-echo imaging in routine MR screening of the brain.

Three-dimensional MR imaging and display of intracranial disease: improvements with the MP-RAGE sequence and gadolinium.

Three-dimensional (3D) image rendering was performed in 14 patients who had undergone magnetic resonance (MR) imaging for focal brain lesions. The MR study included the magnetization-prepared rapid gradient-echo (MP-RAGE) sequence with 64 or 128 partitions. Resultant contiguous sections 2.5 or 1.25 mm thick, respectively, were obtained. Images were acquired before and after administration of gadopentetate dimeglumine. Resultant 3D data sets were processed on a commercially available workstation. Correlative surgical observation was performed in four cases. All data sets were successfully processed into 3D images. The precontrast images proved superior to gadolinium-enhanced images for brain surface rendering. Postcontrast images proved superior for reconstruction of tumors and vascular structures. The 64-partition data set proved sufficient for all postprocessing. Coronal orientation was preferred to sagittal orientation for surface rendering because it provided optimal orthogonal orientation of sulcal and gyral brain surface features. Three-dimensional rendition allowed easy superposition of lesion, brain, vessels, and scalp features--all useful for surgical planning. The central sulcus was easily recognized in the midline partitions and traced mediolaterally for projection on the cortical surface. MP-RAGE provides a 3D data set that can be obtained in just over 3 minutes, from which clinically useful 3D renderings are possible. The rapidity of acquisition and capability for 3D rendering provides additional clinical utility.

MR imaging of the brain in patients with AIDS: value of routine use of i.v. gadopentetate dimeglumine.

OBJECTIVE: A prospective study was conducted to explore the value of routine administration of IV gadopentetate dimeglumine for MR imaging of the brain in patients with AIDS. SUBJECTS AND METHODS: Over a 19-month period, MR images of the brain in 51 consecutive AIDS patients were obtained routinely both with and without IV gadopentetate dimeglumine. Unenhanced and contrast-enhanced images from the resulting 63 studies were viewed together. Findings were classified into one or more of three categories: normal, mass or focal lesions, or white matter disease. The number of focal or mass lesions was recorded. Lesion conspicuity on the unenhanced and enhanced images was compared. Ventricular enlargement was also graded. Available medical records and laboratory data of the patients were reviewed. RESULTS: Of the 63 MR studies reviewed, 39 (62%) were abnormal. In no case was a normal unenhanced MR study rendered abnormal after the administration of gadopentetate dimeglumine. Overall, T2-weighted images showed twice as many focal or mass lesions than contrast-enhanced T1-weighted images did. Most lesions detected on the T2-weighted images did not show enhancement with contrast material. White matter disease was the most common abnormality detected. The group of patients with white matter disease also had the highest occurrence of ventriculomegaly. CONCLUSION: Our study does not support the routine use of gadopentetate dimeglumine for MR imaging of the brain in patients with AIDS. Our experience emphasizes the importance of a normal T2-weighted image.

MP RAGE: a three-dimensional, T1-weighted, gradient-echo sequence--initial experience in the brain.

The authors evaluated a recently developed sequence for magnetic resonance imaging of the brain. The three-dimensional, Fourier-transformed acquisitions require magnetization-prepared 180 degrees radio-frequency pulses and rapid gradient-echo (MP RAGE) sampling. The resulting T1-weighted images were compared with T1-weighted spin-echo (SE) images; both were obtained after paramagnetic contrast material was administered to 33 patients with known or suspected focal brain lesions. Image quality and contrast between gray and white matter were superior with the MP RAGE sequence compared with the T1-weighted SE sequence. The time for obtaining contiguous thin-section (1.3-2.5-mm) images was also comparable, with readily acquired multiplanar reformations obviating additional images. MP RAGE imaging depicted more focal lesions than did T1-weighted SE imaging and matched the number seen with T2-weighted SE imaging. Demonstration of paramagnetic contrast enhancement of lesions was comparable in most cases; however, three lesions showed greater enhancement on T1-weighted SE images and two others were seen only on the T1-weighted SE images. Thus, the MP RAGE sequence may provide an alternative to T1-weighted SE imaging.

Pitfalls of contrast-enhanced imaging in the nervous system.

This brief review covers the evolving clinical role of paramagnetic contrast agents in magnetic resonance imaging of the central nervous system, with particular emphasis on potential pitfalls. The safety and efficacy of Gd-DTPA is now well-established. Approximately 35-40% of all scans performed in this country now utilize the agent. The major pitfalls center on overinterpretation of the characterization of disease by either enhancement or lack thereof in any particular process.