The effect of various stain carriers on the quality and quantity of DNA extracted from dried bloodstains

Summary Bloodstains were made with 200 l blood on each of 11 different common substrates to examine the effect of the stain carrier on the amount and quality of DNA recoverable. High-molecular-weight DNA was extracted from all samples after 2 days. The yield of DNA from each sample varied considerably, not only between the different stain carriers but also within a given category. With a DNA yield of up to 10 g, paper, glass, nylon, wood, smooth leather and wool gave the best results, followed by blue denim and wallpaper (up to 6 g), cotton fabric and carpeting (up to 4 g), and suede (up to 2 g), For several stain carriers the DNA-containing solution was contaminated by chemical substances, which in the case of the blue denim, suede, and carpet samples inhibited the digestion of the DNA with restriction enzymes and prevented DNA typing. The different textures of the stain carriers tested and (as for varying yields on the same carrier) the differing degree of loss of DNA during extraction and the physiological variation in the number of leukocytes in human blood are discussed as possible reasons for the wide range of variation in the amounts of DNA it was possible to extract.Presented in part at the meeting of the North/West German Section of the German Society for Legal Medicine (Essen, May 88) and at the Liège meeting of the English Speaking Group of the Society for Forensic Haemogenetics (Oct 88)     

Traumatic diaphragmatic injury: a review of CT signs and the difference between blunt and penetrating injury

PURPOSE

We aimed to present the frequency of computed tomography (CT) signs of diaphragmatic rupture and the differences between blunt and penetrating trauma.

MATERIALS AND METHODS

The CT scans of 23 patients with surgically proven diaphragmatic tears (both blunt and penetrating) were retrospectively reviewed for previously described CT signs of diaphragmatic injuries. The overall frequency of CT signs was reported; frequency of signs in right- and left-sided injuries and blunt and penetrating trauma were separately tabulated and statistically compared.

RESULTS

The discontinuous diaphragm sign was the most common sign, observed in 95.7% of patients, followed by diaphragmatic thickening (69.6%). While the dependent viscera sign and collar sign were exclusively observed in blunt-trauma patients, organ herniation (P = 0.05) and dangling diaphragm (P = 0.0086) signs were observed significantly more often in blunt trauma than in penetrating trauma. Contiguous injury on either side of the diaphragm was observed more often in penetrating trauma (83.3%) than in blunt trauma (17.7%).

CONCLUSION

Knowledge of the mechanism of injury and familiarity with all CT signs of diaphragmatic injury are necessary to avoid a missed diagnosis because there is variability in the overall occurrence of these signs, with significant differences between blunt and penetrating trauma.Traumatic diaphragmatic injury has been found in 3%–8% of patients undergoing surgical exploration after blunt trauma and in 10% of patients with penetrating trauma (1, 2). The rate of initially missed diagnoses on computed tomography (CT) ranges from 12% to 63%. A missed diagnosis can later present as intrathoracic visceral herniation and strangulation with a mortality rate of 30%–60% (2, 3). In this era of increasing nonoperative management for most cases of blunt abdominal trauma, it becomes essential to diagnose diaphragmatic rupture on imaging to ensure early and timely operative repair of the rupture. The reasons for missed early diagnoses include potentially distracting and more severe thoracic and abdominal visceral injuries and lack of familiarity with all the imaging appearances and signs of diaphragmatic rupture (2, 4).Various imaging modalities including chest radiographs, ultrasonography, CT, and magnetic resonance imaging have been used in the diagnosis of diaphragmatic rupture (1). Currently, multidetector CT (MDCT) is the modality of choice for the detection of diaphragmatic injury. MDCT has increased the accuracy of diagnosis of diaphragmatic rupture. MDCT has inherent technical advantages, such as rapid, volumetric data acquisition for the chest and abdomen within a single breath hold, minimization of motion artifacts, thin-section reconstruction and sagittal and coronal reformat-reducing partial-volume effects that assist in diagnosing subtle defects (1). MDCT also aids in detecting the associated chest, abdomen, ribs, and bony injuries in these polytrauma patients. Various studies have revealed CT to have a variable sensitivity and specificity of 61%–87% and 72%–100%, respectively, for the diagnosis of diaphragmatic rupture (1, 5–7). Killeen et al. (6) demonstrated that the sensitivity for detecting left-sided ruptures (78%) is higher than for right-sided ruptures (50%). This finding has been attributed to the better soft tissue-fat contrast on the left side and the difficulty in diagnosing subtle liver herniation on the right side.Various signs of diaphragmatic rupture have been described on CT. These signs have been divided into direct and indirect signs and signs of uncertain/controversial origin, according to Desir and Ghaye (8), and have been tabulated in 2, 3).

Table 1.

CT signs of diaphragmatic injury^a

Exploring the nature of atheroma and cardiovascular inflammation in vivo using positron emission tomography (PET)

Positron emission tomography (PET) has become widely established in oncology. Subsequently, a whole new “toolbox” of tracers have become available to look at different aspects of cancer cell function and dysfunction, including cell protein production, DNA synthesis, hypoxia and angiogenesis. In the past 5 years, these tools have been used increasingly to look at the other great killer of the developed world: cardiovascular disease. For example, inflammation of the unstable plaque can be imaged with 18-fludeoxyglucose (¹⁸F-FDG), and this uptake can be quantified to show the effect that statins have in reducing inflammation and explains how these drugs can reduce the risk of stroke. ¹⁸F-FDG has also become established in diagnosing and monitoring large-vessel vasculitis and has now entered routine practice. Other agents such as gallium-68 (⁶⁸Ga) octreotide have been shown to identify vascular inflammation possibly more specifically than ¹⁸F-FDG. Hypoxia within the plaque can be imaged with ¹⁸F-fluoromisonidazole and resulting angiogenesis with ¹⁸F-RGD peptides. Active calcification such as that found in unstable atheromatous plaques can be imaged with ¹⁸F-NaF. PET imaging enables us to understand the mechanisms by which cardiovascular disease, including atheroma, leads to morbidity and death and thus increases the chance of finding new and effective treatments.Positron emission tomography (PET) has become established in the staging and restaging of many common cancers and in many ways can be considered to be routine. The most commonly used radiopharmaceutical for PET imaging is 18-fludeoxyglucose (¹⁸F-FDG), but it is a non-specific agent and relies on the fact that cancer cells have a higher uptake of glucose than do normal tissue. There is also increased uptake of ¹⁸F-FDG in other cell types including both lymphocytes and macrophages. Therefore, when reading an ¹⁸F-FDG PET study, care must be taken not to assume that focal uptake of ¹⁸F-FDG is a site of cancer when it could be owing, for example, to inflammation such as can be seen in atheroma in a major artery. The use of fusion imaging with PET-CT allows for better localization and should ensure correct localization (Figure 1). There has been increasing use of ¹⁸F-FDG imaging in inflammation, and recently published European and North American guidelines have recommended that ¹⁸F-FDG PET can be used in cardiovascular inflammation.¹Open in a separate windowFigure 1.Coronal CT (upper left image), 18-fludeoxyglucose (¹⁸F-FDG) (upper right image), positron emission tomography-CT-fused image (lower left image) and maximal intensity projection (lower right image) of focal ¹⁸F-FDG uptake on the right side of the neck, which localizes to atheroma in the internal carotid artery. FOV, field of view.In oncology, the non-specific nature of ¹⁸F-FDG has led to the development of a toolbox of different PET radiopharmaceuticals to look at a range of different aspects of cancer cell function and metabolism, such as carbon-11 (¹¹C) methionine to look at amino acid metabolism, ¹⁸F-fluorolevothymidine to look at DNA synthesis in cancer cells and ¹⁸F-fluoromisonidazole (FMISO) to look at hypoxia.^2–5 Over the next 5–10 years, a similar toolbox may be applied to the imaging of the cardiovascular system (Figure 2), which may well move from the laboratory into more routine clinical practice; therefore, the clinician who is responsible for the provision of PET services will need to know how these techniques can be used.Open in a separate windowFigure 2.Diagram of the positron emission tomography agents that can be used to image factors in the atheromatous plaque. ¹⁸F-FDG, 18-fludeoxyglucose; FMISO, fluoromisonidazole; VEGF, vascular epidermal growth factor.     

A simple method for the quantification of benzodiazepine receptors using iodine-123 iomazenil and single-photon emission tomography

Iodine-123 iomazenil (Iomazenil) is a ligand for central type benzodiazepine receptors that is suitable for single-photon emission tomography (SPET). The purpose of this study was to develop a simple method for the quantification of its binding potential (BP). The method is based on a two-compartment model (K ₁, influx rate constant;k ₂, efflux rate constant;V _T (=K ₁/k ₂), the total distribution volumes relative to the total arterial tracer concentration), and requires two SPET scans and one blood sampling. For a given input function, the radioactivity ratio of the early to delayed scans can be considered to tabulate as a function ofk ₂, and a table lookup procedure provides the correspondingk ₂ value, from whichK ₁ andV _T values are then calculated. The arterial input function is obtained by calibration of the standard input function by the single blood sampling. SPET studies were performed on 14 patients with cerebrovascular diseases, dementia or brain tumours (mean age±SD, 56.0±12.2). None of the patients had any heart, renal or liver disease. A dynamic SPET scan was performed following intravenous bolus injection of Iomazenil. A static SPET scan was performed at 180 min after injection. Frequent blood sampling from the brachial artery was performed on all subjects for determination of the arterial input function. Two-compartment model analysis was validated for calculation of theV _T value of Iomazenil. Good correlations were observed betweenV _T values calculated by three-compartment model analysis and those calculated by the present method, in which the scan time combinations (early scan/delayed scan) used were 15/180 min, 30/180 min or 45/180 min (all combinations:r=0.92), supporting the validity of this method. The present method is simple and applicable for clinical use.     

The mechanism of the localization of 67Gallium citrate in experimental abscesses

⁶⁷Ga accumulation in turpentine-induced abscesses, from 5 h to 20 days old, in the rat has been investigated, and the results indicate that this is dependent on polymorphonuclear leukocyte (PMN) infiltration of the inflamed site. ⁶⁷Ga concentration 24 h after injection correlates well with the activities of the lysosomal enzymes, aryl sulphatase and -glucuronidase, P0.001, and with the DNA content of the tissue. There is no direct relationship with the rate of DNA synthesis.The mechanism of lysosomal incorporation into PMNs is consistent with the factors involved in ⁶⁷Ga uptake into tumours and normal tissues.     

Application of DNA techniques for identification using human dental pulp as a source of DNA

Summary Dental pulp tissue could be obtained in most cases from materials obtained under experimental conditions and from forensic casework (air accidents, burned and putrefied bodies). Teeth extracted during dental treatment (n = 30) were stored for 6 weeks and 4 years at room temperature. In addition teeth (n = 10) extracted from jaw fragments that had been stored for 15 years at room temperature, and teeth extracted post mortem from actual identification cases (n = 8) were investigated. Following extraction from dental pulp tissue the DNA concentration was measured by fluorometry. The amount of DNA obtained from the dental pulp tissue of a single tooth varied from 6 g to 50 g DNA. In most cases high molecular weight DNA was still present although the major portion consisted of degraded DNA. Genomic dot blot hybridization for sex determination using the biotinylated repetitive DNA probe pHY 2.1 was performed and sex was correctly classified in all cases using 50–100 ng target DNA. PCR typing of the HLA-DQ and ApoB 3 VNTR systems from dental pulp tissue DNA was in agreement with the results obtained from blood, bloodstains, or lung tissue. In addition, Southern blot analysis of selected samples using the single locus VNTR probe pYNH24 was successfully performed. In all cases the DNA recovered from dental pulp was unsuitable for multilocus probe analysis.

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Abbreviations BCIP 5-bromo-4-chloro-3-indolylphosphate - RFLP Restriction fragment length polymorphism - VNTR Variable number of tandem repeats - AMP-FLP Amplified fragment length polymorphism Presented in part as poster demonstration at the International Symposium on Mass Disasters, Lausanne 1991     

Antioxidants Taken Orally prior to Diagnostic Radiation Exposure Can Prevent DNA Injury

Purpose

To evaluate efficacy of oral antioxidant treatment given to patients before radiologic procedures in reducing x-ray-induced DNA damage.

A new biodosimetric method: branched DNA-based quantitative detection of B1 DNA in mouse plasma

A simple and accurate method for measuring the biological effects of radiation is of increasing importance, especially in mass casualty scenarios. We have therefore developed a new biodosimetric technique targeting circulating B1 DNA in mouse plasma by branched DNA signal amplification for rapid quantification of plasma DNA. This technology targets repetitive elements of the B1 retrotransposon in the mouse genome, followed by signal amplification using Panomics Quantigene 2.0 reagents. Evaluation was conducted concerning precision, accuracy and linearity. Plasma samples were collected from mice 0–24 h after 0–10 Gy total body irradiation (TBI). The average inter- and intra-assay coefficients of variance were 8.7% and 12.3%, respectively. The average recovery rate of spiked DNA into plasma was 89.5%. This assay revealed that when BALB/c and NIH Swiss mice were exposed to 6 Gy TBI, plasma B1 DNA levels increased significantly at 3 h post-TBI, peaked at 9 h and gradually returned toward baseline levels in 24 h. A dose-dependent change in plasma DNA was observed at 9 h post-TBI; the dose–response relation was monotonic, exhibiting linearity for BALB/c mice from 3 to 6 Gy (r = 0.993) and NIH Swiss mice from 3 to 7 Gy (r = 0.98). This branched DNA-based assay is reliable, accurate and sensitive in detecting plasma B1 DNA quantitatively. A radiation dose-correlated increase in plasma B1 DNA was demonstrated in BALB/c and NIH Swiss mice in the dose range from 3 to 6 Gy, suggesting that plasma B1 DNA has potential as a biomarker for radiation biological effect.Our awareness of the potential risk of accidental and intentional radiation exposure in the form of a terrorist attack has grown in recent years, as unrest, warfare and terrorism have spared few countries or continents. Environmental and ever-growing medical radiation exposures as common components of modern life are also a continued public health concern. Furthermore, plans for space exploration demand better understanding and evaluation of cosmic radiation exposure risks.Physical dosimeters measure radiation exposure, but, unlike biodosimeters, they cannot measure biological effects or individual differences in radiation sensitivity. There is an acknowledged dearth of rapid and effective methods for biodosimetry, especially in the mass casualty scenario. Thus, identifying biomarkers for accurate biodosimetry and assessing their implications are topics of increasing importance [1].The chromosomal aberration assay remains the “gold standard” for biodosimetry and an important part of clinical evaluation of radiation exposure [1, 2] despite newly emerging techniques, such as gene expression profiles [3], proteomics [4], metabolomics [5] and mutation frequency [6]. Unfortunately, there are several aspects of this test as it is currently performed that make it less useful in mass casualty screening and in the acute medical management setting. These include time- and labour-intensive procedures, and the requirement for professional facilities and personnel [1, 2, 7]. The limitations of existing methods prompted us to seek correlated biomarkers and accurate methods to provide a better biological estimation of absorbed dose.The observation that circulating DNA is detected after irradiation was first made by Russian scientists in 1987, when sera from 8–100 Gy irradiated rats were assessed with 0.8% agarose gel indicating an increase in nucleosome DNA [8]. Since then, radiation-released low molecular weight genomic DNA in plasma has been actively studied by another Russian group [9–12]. In 2006, studies of radiation-induced release of mitochondrial DNA into plasma were also reported by Russian scientists [13]. In these experiments, the total circulating DNA in plasma was measured by electrophoresis or by targeting particular housekeeping genes via polymerase chain reaction (PCR) techniques, which are not suitable for a mass casualty situation.Here, we introduce a new approach for biodosimetry through the targeting of the B1 component of plasma DNA, a potential cell or gene stress indicator in the mouse. Through the establishment of the branched DNA (bDNA)-based quantitative assay, we have demonstrated a correlation between plasma B1 DNA and absorbed dose over a specific dose range. In addition, bDNA technology permits direct plasma measurement, circumventing complicated nucleic acid processing procedures. B1 is also called “7SL RNA gene-related non-autonomous retrotransposon” and has been recently identified as being actively involved in the early post-stress genetic response [14]. Since B1 evolutionarily exists in all rodents and mammals, this assay can be extended easily to humans and other species.     

An innovative modification of the retrograde approach to angioplasty and recanalization of the superficial femoral artery

Endovascular therapy has been performed for chronic limb ischemia for nearly 50 years. Superficial femoral artery occlusions can be managed by the retrograde contralateral (“crossover”), antegrade ipsilateral, or retrograde popliteal (“facedown”) approaches. The retrograde approach was initially fraught with limitations and served as a backup option. Refinements to this technique have made it an enticing option and possibly the first choice in selected patients. We herein describe an innovative modification of this method.Endovascular therapy has been performed for chronic limb ischemia since 1964, with intraluminal and subintimal angioplasty of the superficial femoral artery (SFA) gaining popularity in the last decade (1). SFA occlusions can be managed by retrograde contralateral or antegrade ipsilateral approaches (2, 3); when these approaches fail, some practitioners resort to using a re-entry device (4, 5). The retrograde popliteal approach was initially fraught with limitations and served as a backup option (1, 4, 6). However, refinements to this technique have made this an enticing option (2–7), and it has been advocated as a first-line treatment in select patients (3). We herein describe another modification of this method.     

MRI in local staging of rectal cancer: an update

Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer. However, high-resolution phased-array MRI is recommended as a standard imaging modality for preoperative local staging of rectal cancer, with excellent soft tissue contrast, multiplanar capability, and absence of ionizing radiation. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique such as diffusion-weighted imaging and dynamic contrast-enhanced MRI.Colorectal cancer is the second most common cancer in women and the third most common cancer in men with 570 100 and 663 600 estimated new cases per year worldwide, respectively (1). Rectal cancer accounts for approximately 42% of colorectal cancers with 45 000 estimated new cases per year in the United States (2). Prognosis of rectal cancer is determined by depth of invasion, number of involved lymph nodes, and involvement of circumferential resection margin. Management of rectal cancer has evolved over the years with preoperative imaging playing an increasingly prominent role. Initial strategy of clinical diagnosis followed by surgery and postoperative chemotherapy had a high local recurrence rate (27%) and poor survival (48% 5-year survival) (3). Later studies showed that neoadjuvant chemoradiation improves survival and decreases local recurrence rates significantly (4). In addition, it reduces tumor size, facilitates curative resection (5), and may enable sphincter sparing surgery in cancers close to the anorectal junction (6). Neoadjuvant chemoradiotherapy is not indicated in stage I tumors (confined to rectal wall with no nodal involvement), but is recommended for stage II (extends beyond the rectal wall, no nodal involvement) and stage III tumors (regional lymph node involvement). Therefore, in order to avoid unnecessary chemoradiation in stage I cancers, a reliable imaging modality is crucial to precisely define depth of invasion and to identify lymph node involvement (7). Current approach in the management of rectal cancer includes preoperative staging with different imaging modalities followed by neoadjuvant chemoradiotherapy (for stage II/III cancers). This approach has lowered the local recurrence rate (11%) and improved survival (58% 5-year survival) (3).Preoperative imaging for rectal cancer staging is also useful to determine which surgical technique would be more appropriate: recently-developed local excision method of transanal resection or traditional radical resections such as low anterior resection or abdominoperineal resection. Physical examination, endoscopic evaluation, and imaging modalities are used for preoperative staging of rectal cancer. Ideal imaging modality should accurately assess the depth of tumor penetration (T), lymph node involvement (N), presence of distant metastatic disease (M), mesorectal fascia involvement, and anal sphincter involvement. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer.Endoscopic ultrasonography, one of the oldest and most widely used imaging modalities, is reported to assess T staging with 67%–97% accuracy and nodal involvement with 64%–88% accuracy (8–11). Although it has a role in staging of early cancers confined to the wall of the rectum, endoscopic ultrasonography may not assess deeper or higher nodes in the mesorectum and can misinterpret inflammatory or fibrotic changes as metastasis (12). Its value is also limited in the evaluation of near-obstructing tumors, tumors in the upper rectum, and mesorectal fascia involvement (12, 13).Computed tomography (CT) is commonly used in rectal cancer because of its ability to assess entire pelvic anatomy and presence or absence of distant metastasis. However, CT has limited soft tissue contrast for local staging. A meta-analysis of 83 studies showed that CT has 73% accuracy for T staging and 22%–73% accuracy for nodal staging (14). In a recent study, Sinha et al. (15) showed T stage accuracy of 87.1% and N stage accuracy of 87.1%. Although newer multidetector CT technology with multiplanar reformations has improved the accuracy, soft tissue resolution of CT is still inadequate to evaluate early rectal cancers.On the other hand, high-resolution phased-array MRI is recommended as a standard imaging modality for pre-operative local staging of rectal cancer, with excellent soft tissue contrast, functional imaging ability, and multi-planar capability (Figs. 1 and ​and2).2). With these inherent proprieties, MRI fills a gap in clinical practice and helps accurate local staging of rectal cancer prior to management decisions. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique.Open in a separate windowFigure 1. a, b.Axial (a) and coronal (b) fast spin-echo T2-weighted MR images obtained with a phased-array coil on a 3.0 T magnet show the normal anatomy of the pelvis. The rectum (a, arrowhead) is distended with water. Note uterus (a, arrow), and oval-shaped fatty-centered left iliac node (a, curved arrow), which is likely reactive. The iliococcigeal part of the levator ani muscle (b, arrows) extends from the pelvic sidewalls to the anus and joins with the puborectalis muscle (b, arrowheads) to form the external sphincter of the anus (b, curved arrow).Open in a separate windowFigure 2.Axial T2-weighted MR image obtained with an endorectal coil shows the layers of the rectum. Hyperintense submucosa (curved arrows) is surrounded by hypointense muscularis propria (arrows). The mucosa cannot be differentiated from the submucosa, and both layers appear as a single hyperintense layer. Note the levator ani muscle (curved arrows).     

Correlation of minimum apparent diffusion coefficient with maximum standardized uptake on fluorodeoxyglucose PET-CT in patients with rectal adenocarcinoma

PURPOSE

The aim of this study was to retrospectively assess the correlation between minimum apparent diffusion coefficient (ADC_min) values obtained from diffusion-weighted magnetic resonance imaging (MRI) and maximum standardized uptake values (SUV_max) obtained from positron emission tomography-computed tomography (PET-CT) in rectal cancer.

MATERIALS AND METHODS

Forty-one patients with pathologically confirmed rectal adenocarcinoma were included in this study. For preoperative staging, PET-CT and pelvic MRI with diffusion-weighted imaging were performed within one week (mean time interval, 3±1 day). For ADC measurements, the region of interest (ROI) was manually drawn along the border of each hyperintense tumor on b=1000 s/mm² images. After repeating this procedure on each consecutive tumor-containing slice to cover the entire tumoral area, ROIs were copied to ADC maps. ADC_min was determined as the lowest ADC value among all ROIs in each tumor. For SUV_max measurements, whole-body images were assessed visually on transaxial, sagittal, and coronal images. ROIs were determined from the lesions observed on each slice, and SUV_max values were calculated automatically. The mean values of ADC_min and SUV_max were compared using Spearman’s test.

RESULTS

The mean ADC_min was 0.62±0.19×10⁻³ mm²/s (range, 0.368–1.227×10⁻³ mm²/s), the mean SUV_max was 20.07±9.3 (range, 4.3–49.5). A significant negative correlation was found between ADC_min and SUV_max (r=−0.347; P = 0.026).

CONCLUSION

There was a significant negative correlation between the ADC_min and SUV_max values in rectal adenocarcinomas.Diffusion-weighted imaging (DWI) is a widely used technique for disease evaluation in oncology (1, 2). In rectal cancer, the applications of DWI include tumor detection, tumor characterization, distinguishing tumor tissue from nontumor tissue, and monitoring and predicting treatment response (3–8). For local staging of rectal cancer, adding DWI to conventional magnetic resonance imaging (MRI) yields better identification of tumor borders and locoregional lymph nodes than conventional MRI alone (9, 10).The apparent diffusion coefficient (ADC) map obtained from DWI shows the freedom of water diffusion, and values calculated on the map are useful parameters in tissue characterization. By performing diffusion-weighted (DW) MRI with at least two diffusion weightings, or b values, the differential signal attenuation at different b values can be used to calculate the ADC (2). Regardless of the tumor type and location, the ADC values reflect tumor morphology, including the cellular density, integrity of cell membrane, and nuclear-to-cytoplasm ratio (11, 12).Positron emission tomography/computed tomography (PET-CT) has become a crucial method in cancer imaging, both for diagnosis and staging, as well as for offering prognostic information based on tumor response. In PET-CT, the standardized uptake value (SUV) is a measure of fluorodeoxyglucose (FDG) uptake, which has been shown to be helpful in establishing the metabolic activity level of a tumor (13–15).Both ADC and SUV have been used as important imaging parameters to supplement visual interpretation. To our knowledge, few studies have evaluated the relationship between ADC and SUV in cancer patients (16–18). The aim of the present study was to retrospectively assess the correlation between the minimum ADC (ADC_min) on DWI and maximum SUV (SUV_max) values from FDG PET-CT in rectal cancer.     

Impact of arterial reocclusion and distal fragmentation during thrombolysis among patients with acute ischemic stroke

BACKGROUND AND PURPOSE: Arterial reocclusion and distal embolization are known complications of ischemic stroke intervention, impacting treatment strategies and device design. We sought to determine their rates of occurrence and effects on long-term outcomes during endovascular treatment of patients with acute ischemic stroke.MATERIALS AND METHODS: Retrospective analysis of data from 4 prospective acute stroke protocols was performed. Patients underwent the standard technique for parent vessel angiography followed by pharmacologic thrombolysis and/or sonographic thrombolysis and/or mechanical thrombus disruption. Certain patients also received systemic heparin or abciximab therapy. Demographic, clinical, and angiographic variables were assessed at onset, 24 hours, 1 week, and 1–3 months after the event. “Distal embolization” was defined qualitatively as appearance of an occlusion on a downstream vessel. “Arterial reocclusion” was defined as subsequent reocclusion of the target vessel after initial recanalization had been achieved.RESULTS: Arterial reocclusion occurred in 18% of these patients, whereas distal embolization occurred in 16% of the 91 patients treated in these protocols. Arterial reocclusion, but not distal embolization, was associated with a lower likelihood of favorable outcome at 1–3 months (P = .05; odds ratio, 3.9; 95% confidence interval, 0.01–0.98) after adjusting for age, initial National Institutes of Health Stroke Scale scores, sex, time to treatment, initial angiographic grade, symptomatic intracranial hemorrhage, and final recanalization.CONCLUSIONS: Arterial reocclusion and distal embolization occur in 16%–18% of patients with stroke undergoing endovascular intervention. Only arterial reocclusion is associated with poor long-term outcome. Prospective studies are needed to identify risk factors for their occurrence and possible preventive therapies.

Although it is generally believed that vessel recanalization leads to improved outcome in acute ischemic stroke,^1–3 complications of thrombolysis, such as arterial reocclusion (Fig 1) and downstream embolization of thrombus (Fig 2), may counter the benefits of therapy. Early reocclusion following thrombolysis has been shown by transcranial Doppler (TCD) to occur in 34% of patients receiving intravenous (IV) recombinant tissue plasminogen activator (rtPA) and may result in neurologic worsening in many of these patients.⁴ Preliminary studies of arterial reocclusion during endovascular treatment have shown rates of 17%, with a subsequent association with poor outcome.⁵ The concern for arterial reocclusion may lead physicians to administer anticoagulation or platelet glycoprotein (GP) IIb/IIIa inhibitors in patients undergoing endovascular therapy,^6,7 despite the increased risk of intracranial hemorrhage.⁸Open in a separate windowFig 1.Arterial reocclusion. A 54-year-old woman, status post IV tissue plasminogen activator, has a left M1 occlusion seen in the anteroposterior (A) and lateral (B) planes (Qureshi grade 3A). After mechanical thrombolysis, there is improved flow in the superior division, frontal branches of M2 (arrows, C and D; Qureshi grade 2). However, the final angiogram shows reocclusion of the M1 stem similar to her initial angiographic appearance (E and F, Thrombolysis in Myocardial Infarction grade 0, Qureshi grade 3A).Open in a separate windowFig 2.Distal embolization. A 53-year-old woman has right carotid terminus occlusion seen in the anteroposterior (panel A) and lateral (panel B) projections (Qureshi grade 5). Status post IA reteplase and intravenous abciximab, there is flow through the anterior cerebral artery seen in the anteroposterior (C) and lateral (D) projections. The arrow (D) indicates an occlusion of the callosomarginal branch, whereas the pericallosal branch is filling well (Qureshi grade 3B).Concern for distal embolization has impacted device design in ischemic stroke therapy, serving as the rationale for the use of distal protection devices in carotid artery stent-placement procedures^9–11 and the basis of the balloon-guide catheter for the Merci retriever (Concentric Medical, Mountain View, Calif), though exact rates of distal embolization were not known in the MERCI trial.^12,13 Studies of distal embolization during carotid artery stent placement procedures, by using diffusion-weighted imaging (DWI) techniques as a marker, estimate occurrence rates of 17%–30%, even with the use of distal protection devices.^14–16We sought to evaluate the occurrence of distal embolization and arterial reocclusion in patients undergoing revascularization therapy in 4 prospective acute stroke protocols: intra-arterial (IA) reteplase and mechanical thrombus disruption (MTD, group 1),^5,17,18 the EKOS MicroLysUS North American trial (group 2),¹⁹ MTD following IV thrombolysis (group 3),²⁰ and IA reteplase and IV abciximab (FDA IND 9180, group 4).²¹     

CT assessment of vocal cord medialization

BACKGROUND AND PURPOSE: Unilateral vocal cord paralysis (UVCP) occurs after iatrogenic injury or disease process and is associated with dysphonia and aspiration. Various surgical options are available for treatment of UVCP, including vocal cord medialization thyroplasty and injection laryngoplasty. These augmentative procedures improve phonation and airway protection. Our purpose was to demonstrate the CT appearance of implants used for the treatment of UVCP.METHODS: Twelve patients treated surgically for UVCP were studied with helical CT. The vocal cords were augmented by using Silastic implants (n = 7), polytetrafluoroethylene (Gore-Tex) implants (n = 2), Teflon injections (n = 2), or fat injection (n = 1). Augmented vocal cords were characterized by size, shape, and Hounsfield units (HU). Two other patients with failed medialization thyroplasty were evaluated for the position of the extruded implant relative to the paralyzed vocal cord.RESULTS: The 7 Silastic implants were triangular and hyperattenuated (293.4 ± 90.4 HU). The 2 Gore-Tex implants were heterogeneous with lobulated medial margins and were hyperattenuating (320 and 414 HU). The injected materials demonstrated ovoid/masslike configurations: the 2 Teflon injections were hyperattenuated (107 and 429 HU), and the fat injection was hypoattenuated (−102 HU). Inferior displacement of the implant was demonstrated relative to the true vocal cord in 2 patients with failed Silastic thyroplasties.CONCLUSION: CT can distinguish various types of vocal cord augmentation. Silastic implants are recognized by their characteristic triangular configuration. The Gore-Tex implants had unique heterogeneous attenuation with lobulated medial margins. Fat and Teflon injections both appear ovoid/masslike. Teflon injection should not be mistaken for tumor.

Unilateral vocal cord paralysis (UVCP) can cause dysphonia and aspiration because of glottic incompetency. UVCP is often the result of recurrent laryngeal nerve involvement from iatrogenic injury following thyroid surgery or from direct tumor extension. With the exception of the cricothyroid, the intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve. Injury to the nerve results in diminished vocal fold tone, bulk, and mobility.¹ CT can be used to characterize UVCP. In a representative patient, UVCP presented as a flaccid atrophic left vocal cord. It was paramedian in position, and there was associated dilation of the glottic airway (Fig 1).Open in a separate windowFig 1.Postcontrast axial CT image of a flaccid atrophic left vocal cord (arrow). It is paramedian in position, and there is associated dilation of the glottic airway.Surgical options for treatment of UVCP include vocal cord medialization by injection laryngoplasty or by thyroplasty.² Injection laryngoplasty involves direct injection of a biocompatible material into a paralyzed true vocal cord guided by endoscopic visualization. This provides bulk to the affected vocal cord, thereby improving its opposition to the unaffected contralateral vocal cord. It is a minimally invasive technically simple procedure that can be performed with the patient under local anesthesia.² Injection laryngoplasty is the oldest method of treatment of UVCP. Paraffin was used as an injection material as early as 1911.³ A number of other substances have been used to augment vocal cords. However, foreign body reactions to substances such as polytetrafluoroethylene (PTFE) (Teflon; Dupont, Wilmington, Del) and migration from injection sites have limited the substances currently acceptable for injection laryngoplasty primarily to collagen and fat.⁴Medialization thyroplasty was first described by Payr⁵ in 1915 and was later described by Isshiki et al⁶ in 1975. The technique was modified by Montgomery in 1997.⁷ The Montgomery prosthesis is Silastic (Dow Corning, Auburn, Mich) and is constructed of triangular plastic. It is inserted surgically through a window in the thyroid lamina at the level of the vocal cord. The contour of the implant is designed to medialize the true vocal cord, thereby improving glottic competency and facilitating phonation and airway protection.⁷ Videostroboscopy evaluates vocal fold movement and vibration in patients with vocal cord paralysis.⁸ Videostroboscopy is often used to assess patients with vocal cord augmentation and help determine which type of procedure will provide the most benefit. Fig 2A, -B shows the preoperative videostroboscopy in a patient with cervical esophageal cancer, demonstrating a paralyzed left vocal cord. Following medialization thyroplasty using a Montgomery Silastic implant, videostroboscopy (Fig 2C, -D) demonstrated that the left vocal fold was midline and glottic closure was improved during vocal fold adduction.Open in a separate windowFig 2.A and B, A 57-year-old woman status postresection of cervical esophageal cancer, with left vocal cord paralysis. Preoperative videostroboscopy demonstrates the paralyzed vocal cord (arrow) during abduction (A) and adduction (B). Note the complete lack of glottic closure during vocal cord adduction. A indicates anterior commissure.C and D, Postoperative videostroboscopy in abduction (C) and adduction (D), in the same patient following medialization thyroplasty performed using a Montgomery Silastic implant. The left vocal fold is now midline, and glottic closure is improved during vocal cord abduction (arrow in C) and adduction (arrow in D). A indicates anterior commissure.The CT appearances of the medialization thyroplasty and injection laryngoplasty are unique. The purpose of this study was to demonstrate the CT appearance of vocal cord augmentation procedures performed by otolaryngologists and head and neck surgeons. An understanding of the appearance of vocal cord augmentations is useful to avoid misinterpretation of implants as pathology. In addition, accurate localization of extruded implants with high-resolution CT is helpful before revision surgery.     

Identification in blood stains through DNA typing with C4 and HLA-DR probes

Summary A restriction fragment length polymorphism analysis using double digestion of DNA preparations with XbaI and BglII restriction enzymes and hybridization with C4 and HLA-DR probes is described. The typing conditions selected reveal extensive individual variation in both C4 and DR gene regions. In our panel of 46 unrelated individuals, 37 different phenotypic patterns were recognized when both probes were used, and preliminary discriminative power values of 0.865 and 0.914 were calculated for C4 and DR, respectively. The probability of a chance match using both systems is probably about 1.5 · 10^–2.The potential of this method for individual identification of blood stains was demonstrated on DNA prepared from 6-month-old dried blood stains from seven panel individuals. The seven individuals were all identified when comparing stain DNA patterns with panel control patterns. No RFLP pattern changes were observed following storage of blood stains. Based on these experiments with C4 and DR DNA typing under laboratory conditions, it is concluded that DNA typing with such probes may become a powerful tool in future stain identification analyses.     

Validation of the STR system FES/FPS for forensic purposes in an Austrian population sample

The short tandem repeat system FES/FPS was amplified by the polymerase chain reaction (PCR) in 211 unrelated Austrians and analysed by horizontal, non-denaturing electrophoresis. The allele distribution was in Hardy-Weinberg equilibrium. No mutations were found in 25 families (50 meioses). The mean exclusion chance was 0.49, the discriminating power 0.86 and the heterozygosity rate 74.4%. Amplification could be achieved with as little as 100 pg of high molecular weight DNA, which could be reduced to 75 pg by using 32 instead of 30 cycles. By reamplifying 1 l for another 15 cycles, the threshold could be reduced to less than 20 pg. In a degradation experiment DNA extracted from bloodstains stored for up to 24 days in a moist chamber and DNA boiled for up to 18 min could be amplified.     

The potential role of modern US in the follow-up of patients with retroperitoneal fibrosis

PURPOSE

We aimed to evaluate a standardized ultrasonography (US) algorithm for the visualization of pathologic para-aortic tissue in retroperitoneal fibrosis (RPF).

MATERIALS AND METHODS

Thirty-five patients with lumbar RPF of typical extent, as determined by abdominal magnetic resonance imaging, were included. Examinations were conducted using standardized abdominal US with axial sections obtained at the levels of the renal arteries, aortic bifurcation, and both common iliac arteries. Imaging of each section was acquired with fundamental B-mode (US) and tissue harmonic imaging, respectively. In addition, we examined RPF visualized using extended field-of-view US.

RESULTS

Tissue harmonic imaging adequately visualized RPF of typical extent in 33 patients (94.2%). Excellent and good visualization with mild artifacts were achieved in 25 (71.4%) and six (17.1%) patients, respectively. When RPF spread along the iliac arteries, excellent visualization was achieved in 38.7% for the left side and 34.5% for the right side. There were significantly fewer diagnostic examinations for the right iliac (27.6%) than for the left one (9.7%) (P = 0.016). Overall, harmonic imaging achieved significantly better visualization than fundamental B-Mode (P < 0.001).

CONCLUSION

We described the first systematic evaluation of RPF visualization by modern US techniques. The best imaging quality was found in the typical RPF location, at the level of the aortic bifurcation. These results advocate for the presented US algorithm as an efficient follow-up alternative to cross-sectional imaging in RPF patients.Chronic periaortitis or retroperitoneal fibrosis (RPF) is a rare fibrosing disease that affects para-aortic tissues (1–3). It typically presents as a proliferating lumbar process surrounding the ureters and retroperitoneal vascular structures (Fig. 1) (2, 4). Sporadic, atypical manifestations in pelvic and mesenteric regions are also possible (5).Open in a separate windowFigure 1. a–c.Typical extent of the retroperitoneal fibrosis surrounding the infrarenal aorta (a). Spreading of the fibrosis to the renal arteries and along the common iliac arteries (b). Standardized US examination with four transverse sections (c). AO, aorta; AIC, common iliac artery; RA, renal artery; RPF, retroperitoneal fibrosis.Magnetic resonance imaging (MRI) allows precise evaluation of the extent and complications (6). RPF presents as hypointense (often isointense to striated muscle) plaques in native T1-weighted magnetic resonance (MR) images with significant gadolinium contrast enhancement of active and untreated retroperitoneal fibrosis (7–9).Ultrasonography (US) is primarily used in patients with RPF for a rapid and practical diagnosis of consecutive hydronephrosis (6). RPF presents as a smooth-bordered mass with either an echo-poor or echo-free signal (10, 11). Two studies in the 1980s indicated that US revealed only a poor overall sensitivity in the detection of RPF (12, 13). Feinstein et al. (14) reported that only 25% of affected patients with computed tomography (CT)-mediated diagnosis of RPF showed corresponding ultrasonographic abnormalities. Since that time the quality of US scanners has improved dramatically, and modern techniques, such as tissue harmonic imaging (THI) and extended field-of-view US, have significant advantages for routine clinical diagnosis (15–17). Today, US has established itself as an effective and cost-efficient imaging method for the screening and follow-up of infrarenal aortic aneurysms (18, 19). US, however, is not used routinely for RPF follow-up, nor has a systematic evaluation of modern ultrasonographic methods been available to date.The aim of the present study was to evaluate the potential role of modern ultrasonographic techniques for the visualization of fibrous tissue in patients with prediagnosed RPF.     

Preoperative transarterial particulate embolization of juvenile angiofibroma with intracranial extension: Technical and clinical outcomes

Purpose

This retrospective study was constructed to assess the beneficial effects of preoperative transarterial particulate embolization of juvenile angiofibroma (JA) with intracranial extension in terms of intraoperative blood loss and local tumor recurrence.