Molecular pharmacology of P2Y-receptors

Membrane-bound P2-receptors mediate the actions of extracellular nucleotides in cell-to-cell signalling. P2X-receptors are ligand-gated ion channels, whereas P2Y-receptors belong to the superfamily of G-protein-coupled receptors. So far, the P2Y family is composed of eight cloned and functionally defined subtypes. Five of them (P2Y1, P2Y2, P2Y4, P2Y6 and P2Y11) are present in human tissues. The P2Y3-, p2y8- and tp2y-receptors may be species orthologues. The principal physiological agonists of the cloned human P2Y-receptors are ADP (P2Y1), UTP/ATP (P2Y2), UTP (P2Y4), UDP (P2Y6) and ATP (P2Y11). The rat P2Y4-receptor is activated by both UTP and ATP. Specific patterns of polar amino acid residues in the exofacial portions of transmembrane domains (TMs) 6 and 7 of the P2Y-receptors may account for the ligand specificity of the subtypes. Suramin acts as an antagonist at most P2Y-receptors with the exception of P2Y4- and tp2y-receptors. PPADS has been shown to block P2Y1-, the human P2Y4- and P2Y6-receptors. The nucleotide analogue 2'-deoxy-N6-methyladenosine-3',5'-bisphosphate (MRS 2179), in contrast, seems to be a potent and selective antagonist at the P2Y1-receptor. All cloned and functionally expressed P2Y-receptors are able to couple to phospholipase C. The P2Y11-receptor mediates in addition a stimulation of adenylate cyclase and the tp2y-receptor an inhibition of this signal transduction pathway. Other functionally defined subtypes, e.g., the receptor mediating an inhibition of adenylate cyclase in blood platelets, are not yet cloned. The distribution of P2Y1 mRNA is widespread. The receptor plays a crucial role in blood platelet aggregation and mediates the adenine nucleotide-induced release of the endothelium-derived relaxing factor nitric oxide. P2Y1-receptors may also be involved in the modulation of neuro-neural signalling transmission. P2Y2 transcripts are abundantly distributed. One important example for its functional role is the control of chloride ion fluxes in airway epithelia. The P2Y4-receptor is highly expressed in the placenta. The distribution of the P2Y6-receptor is widespread including heart, blood vessels and brain. The P2Y11-receptor may play a role in the differentiation of immunocytes.

Quantitative analysis of survival motor neuron copies: identification of subtle SMN1 mutations in patients with spinal muscular atrophy, genotype-phenotype correlation, and implications for genetic counseling

Problems with diagnosis and genetic counseling occur for patients with autosomal recessive proximal spinal muscular atrophy (SMA) who do not show the most common mutation: homozygous absence of at least exon 7 of the telomeric survival motor neuron gene (SMN1). Here we present molecular genetic data for 42 independent nondeleted SMA patients. A nonradioactive quantitative PCR test showed one SMN1 copy in 19 patients (45%). By sequencing cloned reverse-transcription (RT) PCR products or genomic fragments of SMN1, we identified nine different mutations in 18 of the 19 patients, six described for the first time: three missense mutations (Y272C, T274I, S262I), three frameshift mutations in exons 2a, 2b, and 4 (124insT, 241-242ins4, 591delA), one nonsense mutation in exon 1 (Q15X), one Alu-mediated deletion from intron 4 to intron 6, and one donor splice site mutation in intron 7 (c.922+6T-->G). The most frequent mutation, Y272C, was found in 6 (33%) of 18 patients. Each intragenic mutation found in at least two patients occurred on the same haplotype background, indicating founder mutations. Genotype-phenotype correlation allowed inference of the effect of each mutation on the function of the SMN1 protein and the role of the SMN2 copy number in modulating the SMA phenotype. In 14 of 23 SMA patients with two SMN1 copies, at least one intact SMN1 copy was sequenced, which excludes a 5q-SMA and suggests the existence of further gene(s) responsible for approximately 4%-5% of phenotypes indistinguishable from SMA. We determined the validity of the test, and we discuss its practical implications and limitations.

Identification of a candidate modifying gene for spinal muscular atrophy by comparative genomics

Spinal muscular atrophy (SMA) is a common recessive disorder characterized by the loss of lower motor neurons in the spinal cord. The disease has been classified into three types based on age of onset and severity. SMA I-III all map to chromosome 5q13 (refs 2,3), and nearly all patients display deletions or gene conversions of the survival motor neuron (SMN1) gene. Some correlation has been established between SMN protein levels and disease course; nevertheless, the genetic basis for SMA phenotypic variability remains unclear, and it has been postulated that the loss of an additional modifying factor contributes to the severity of type I SMA. Using comparative genomics to screen for such a factor among evolutionarily conserved sequences between mouse and human, we have identified a novel transcript, H4F5, which lies closer to SMN1 than any previously identified gene in the region. A multi-copy microsatellite marker that is deleted in more than 90% of type I SMA chromosomes is embedded in an intron of this gene, indicating that H4F5 is also highly deleted in type I SMA chromosomes, and thus is a candidate phenotypic modifier for SMA.

MR-guided transgluteal biopsies with an open low-field system in patients with clinically suspected prostate cancer: technique and preliminary results

The purpose of this study was to examine the feasibility and safety of MR-guided biopsies with a transgluteal approach in patients with uncertain or suspicious prostate lesions. Twenty-five patients with uncertain or suspicious focal prostate lesions detected by high-field MR imaging of the prostate gland using endorectal coil imaging were biopsied with a transgluteal approach in a low-field MRI system (0.2 T, Concerto, Siemens). The procedures were guided using T1-weighted FLASH sequences. The prostate gland was biopsied repeatedly with a coaxial technique through a 15-gauge pencil tip with a 16-gauge biopsy handy (median 3.8 samples per patient). Complications and biopsy findings were documented retrospectively. Using T1-weighted sequences biopsy procedures were performed successfully with MR guidance in all cases without any side effects or complications. The median intervention time was 11.3 min. Pathological findings revealed ten cases of hyperplasia or atrophy, three cases of prostatitis, ten cases of carcinoma and two cases of normal tissue. The clinical follow-up showed that in two patients prostate cancer was missed at MR-guided biopsy. Transgluteal MR-guided biopsy of the prostate gland is a safe and promising approach for histological clarification of uncertain or suspicious lesions.

Origin and course of the extracranial vertebral artery: CTA findings and embryologic considerations

PURPOSE

The aim of this study was to show the different origins and courses of the extracranial VA on CTA with special emphasis on embryological considerations. The duplicated VA is an anomaly that has been assumed to predispose for dissection and to be associated with aneurysms. We report its frequency and clinical significance.

METHODS

We retrospectively reviewed CTA of 539 patients by using a contrast-enhanced CTA protocol of the VA on CT.

RESULTS

Ninety-four-point-two percent of left VA originated from left subclavian artery and entered the transverse foramen at C6 in nearly all cases. Six-point-three-percent of left VA (m = 4 %, f  = 10 %) originated from the aortic arch and entered the transverse foramen either at C4, C5 or C7 but never at C6. One case of an aberrant retroesophageal right VA originated from the aortic arch distal to the left subclavian artery and entered at C7 (0.19 %). All other right VA originated from the right subclavian artery (99.8 %) and entered between C4 and C6. We diagnosed four cases of duplicated VA (0.74 %) with a female predominance (1.9 %) without any signs of dissection on CTA. Two cases with VA duplication had intracranial arterial aneurysms.

CONCLUSIONS

The VA is a longitudinal anastomosis of segmental metameric arteries. The level of entrance into the transverse foramen indicates which metameric artery or arteries persist. Duplication corresponds to persistence of two segmental arteries and is a rare phenomenon. VA duplication might be associated with vascular lesions.

Whole-Body Integrated [68Ga]PSMA-11-PET/MR Imaging in Patients with Recurrent Prostate Cancer: Comparison with Whole-Body PET/CT as the Standard of Reference

PURPOSE

The aim of this study was to evaluate the detection rate of [⁶⁸Ga]prostate-specific membrane antigen ([⁶⁸Ga]PSMA-11) positron emission tomography (PET)/magnetic resonance imaging (MRI) and to compare it with [⁶⁸Ga]PSMA-11 PET/X-ray computed tomography (CT) in patients with recurrent prostate cancer (PC) after radical prostatectomy.

PROCEDURES

A total of 93 patients with biochemically recurrent prostate cancer underwent [⁶⁸Ga]PSMA-11 PET/CT and subsequently a whole-body integrated PET/MRI examination. Board certified nuclear medicine physicians and radiologists evaluated PET/CT and PET/MRI datasets regarding identification of tumor lesions ((i) lymph nodes, (ii) bone lesions, (iii) local recurrence, and (iv) parenchymal lesions) based on maximum [⁶⁸Ga]PSMA-11 uptake as well as morphological changes. Quality of PET images for both PET/CT and PET/MRI were rated using a 5-point scoring system by evaluating lesion homogeneity, contrast, contour, and delineation. Wilcoxon signed-rank tests were used to determine statistical differences.

RESULTS

PC relapse was detected in 62/93 patients. PET/MRI detected 148 out of 150 lesions described in PET/CT. In addition, PET/MRI detected 11 lesions not detected in PET/CT (5 lymph nodes, 6 local recurrences). The exact McNemar statistical test (one-sided) showed significant difference between PET/CT and PET/MRI for diagnosis of local recurrence (p value = 0.031). Diagnostic confidence for (iii) was higher in PET/MRI compared with PET/CT (PET/CT = 1.1; PET/MRI = 4.9). Diagnostic confidence for (i) (PET/CT = 4.9; PET/MRI = 4.6), (ii) (PET/CT = 4.9; PET/MRI = 4.6), and (iv) (PET/CT = 4.6; PET/MRI = 4.8) was equivalent between PET/MRI and PET/CT.

CONCLUSIONS

Integrated [⁶⁸Ga]PSMA-11 PET/MRI provides a similarly high diagnostic performance for localization of recurrent PC as PET/CT. For the detection of local recurrences [⁶⁸Ga]PSMA-11 PET/MRI is superior compared with [⁶⁸Ga]PSMA-11 PET/CT.

1-kilowatt CW all-fiber laser oscillator pumped with wavelength-beam-combined diode stacks

We have demonstrated a monolithic cladding-pumped ytterbium-doped single all-fiber laser oscillator generating 1 kW of CW signal power at 1080 nm with 71% slope efficiency and near diffraction-limited beam quality. Fiber components were highly integrated on "spliceless" passive fibers to promote laser efficiency and alleviate non-linear effects. The laser was pumped through a 7:1 pump combiner with seven 200-W 91x nm fiber-pigtailed wavelength-beam-combined diode-stack modules. The signal power of such a single all-fiber laser oscillator showed no evidence of roll-over, and the highest output was limited only by available pump power.

Laparoscopic treatment of liver cysts

Symptomatic simple liver cysts should be treated. In this report we describe the results of a straightforward, well-tolerated laparoscopic operation for this condition. Between 1990 and 1996 we performed 19 laparoscopic liver cyst excisions. The exposed portion of the cyst wall was excised and a piece of omentum was secured into the remaining cyst cavity to prevent recurrence. The average age of the patients was 65 years (range 30 to 81 years). Eight patients (42%) had single simple cysts, nine patients (47%) had multiple simple cysts, and two patients (11%) had polycystic liver disease. Fifty-three percent of the patients had previous abdominal operations, 47% had undergone previous needle aspirations, and one had previously undergone unsuccessful laparoscopic cyst decompression elsewhere. The indications for surgery included abdominal pain, mass, early satiety, malaise, bloating, and shortness of breath. Two patients underwent concurrent cholecystectomies, and one patient underwent concurrent laparoscopic Nissen fundoplication. Follow-up, which averaged 32 months (range 3 to 68 months), is complete in all patients. There was one treatment failure among the patients with simple cysts. Both patients with polycystic liver disease have had recurrent symptoms. The laparoscopic approach to simple liver cysts is relatively straightforward, and if certain technical principles are adhered to, the success rate is very high.

MR-guided biopsies of lesions in the retroperitoneal space: technique and results

The purpose of this study was to evaluate the safety and precision of MRI-guided biopsies of retroperitoneal space-occupying tumors in an open low-field system. In 30 patients with indistinct retroperitoneal tumors [paraaortic lesion (n=20), kidney (n=2), suprarenal gland (n=3) and pancreas (n=5)] MR-guided biopsies were performed using a low-field system (0.2 T, Magnetom Concerto, Siemens, Germany). For the monitoring of the biopsies T1-weighted FLASH sequences (TR/TE=160/5 ms; 90 degrees ) were used in all patients and modified FLASH sequences (TR/TE=160/13 ms; 90 degrees ) in ten patients. After positioning of the needle in the tumors 114 biopsy specimens were acquired in coaxial technique with 16-gauge cutting needles (Somatex, Germany). The biopsies were successfully performed in all patients without vascular or organ injuries. The visualization of the aortic blood flow with MRI facilitated the biopsy procedures of paraaortic lesions. The size of the lesions ranged from 1.6 to 7.5 cm. The median distance of the biopsy access path was 10.4 cm. Adequate specimens were obtained in 28 cases (93.3%) resulting in a correct histological classification of 27 lesions (90%). In conclusion, MR-guided biopsies of retroperitoneal lesions using an open low-field system can be performed safely and accurately and is an alternative to CT-guided biopsies.

Determination of synapsin I and synaptophysin in body fluids by two-site enzyme-linked immunosorbent assays

Two-site enzyme-linked immunosorbent assays (ELISA) have been established for the specific and sensitive determination of two membrane proteins of the small synaptic vesicles (SSV), namely: peripheral synapsin I and integral synaptophysin. The ELISA used highly specific capture monoclonal antibodies (mAB) and polyclonal antibodies (pAB) as detectors. For synapsin I, the mAB were newly generated, whereas for synaptophysin, the commercially available mAB SY38 was applied. In order to calibrate the ELISA and to raise pAB, both proteins were purified in the mg-range. Synapsin I was purified by conventional means from human and porcine brain and synaptophysin was purified by immunoaffinity chromatography from porcine brain. Using the ELISA, neither synapsin I nor synaptophysin could be determined in serum or cerebrospinal fluid (CSF) from healthy donors or patients suffering various neurological disorders or pheochromocytomas. For this reason, the degradation of both proteins in serum and CSF was investigated. With the exception of synaptophysin measured in serum, both proteins exhibited fast rates of degradation. Despite the negative results in human body fluids, the two ELISA are appropriate for the quantification of these membrane proteins in neuronal or neuroendocrine cell extracts or preparations of SSV.

Automated Detection of Lung Nodules in Multidetector CT: Influence of Different Reconstruction Protocols on Performance of a Software Prototype

PURPOSE

To evaluate the accuracy of software for computer-aided detection (CAD) of lung nodules using different reconstruction slice thickness protocols in multidetector CT.

MATERIALS AND METHODS

Raw image data sets for 15 patients who had undergone 16-row multidetector CT (MDCT) for known pulmonary nodules were reconstructed at a reconstruction thickness of 5.0, 2.0 and 1.0 mm with a reconstruction increment of 1.5, 1.0 and 0.5 mm, respectively. The "Nodule Enhanced Viewing" (NEV) tool of LungCare for computer-aided detection of lung nodules was applied to the reconstructed images. The reconstructed images were also blinded and then evaluated by 2 radiologists (A and B). Data from the evaluating radiologists and CAD was then compared to an independent reference standard established using the consensus of 2 independent experienced chest radiologists. The eligible nodules were grouped according to their size (diameter > 10, 5 - 10, < 5 mm) for assessment. Statistical analysis was performed using the receiver operating characteristic (ROC) curve analysis, t-test and two-rater Cohen's Kappa co-efficient.

RESULTS

A total of 103 nodules were included in the reference standard by the consensus panel. The performance of CAD was marginally lower than that of readers at a 5.0-mm reconstruction thickness (AUC = 0.522, 0.517 and 0.497 for A, B and CAD, respectively). In the case of 2.0-mm reconstruction slices, the performance of CAD was better than that of the readers (AUC = 0.524, 0.524 and 0.614 for A, B and CAD, respectively). CAD was found to be significantly superior to radiologists in the case of 1.0-mm reconstruction slices (AUC = 0.537, 0.531 and 0.675 for A, B and CAD, respectively). The sensitivity at a reconstruction thickness of 1.0 mm was determined to be 66.99 %, 68.93 % and 80.58 % for A, B and CAD, respectively. The time required for detection was shortest for CAD at reconstruction slices of 1.0 mm (mean t = 4 min). The performance of radiologists was greatly enhanced when using CAD: sensitivity 91.26 % and 94.17 % for CAD+A and CAD+B, respectively (AUC = 0.889 and 0.917). CAD was most advantageous in the detection of nodules < 10 mm.

CONCLUSION

At a 1.0-mm reconstruction thickness, CAD's ability to detect nodules < 10 mm is superior to that of radiologists and its relatively short evaluation time makes it a viable second reader.

Parathyroid hormone (1-34) receptor-binding and second-messenger response in rat incisor odontoblasts

Even though indirect evidence indicates that PTH exerts an anabolic effect on dentinogenesis, the existence of PTH receptors and any second-messenger response in odontoblasts have not been demonstrated. The aim of this study was to investigate whether rat incisor odontoblasts express PTH receptors, and to identify which second messenger pathway the hormone may activate. Odontoblasts were dissected from rat incisors. Amino-terminal (1-34) fragment rat PTH [rPTH(1-34)] conjugated to fluorescein isothiocyanate visualized receptor sites on the cell surface. Upon incubation of odontoblasts with rPTH(1-34), cAMP formation was increased. However, no fluctuations in intracellular calcium activity were observed upon rPTH(1-34) stimulation when using Fura-2 as a Ca2+ probe. In long-time incubations, stimulation with PTH(1-34) upregulated APase activity. The results demonstrate that rPTH(1-34) evokes an anabolic response in dentinogenically active odontoblasts, and that this may be mediated through the protein kinase A/cAMP pathway, whereas no indications for Ca2+ as a second messenger were evident.

Mediastinoscopy in the investigation of primary mediastinal lymphadenopathy

Mediastinoscopy was introduced by Carlens (1) in 1959 to obtain lymph node biopsies from the superior mediastinum in patients with bronchogenic carcinoma. The technique has been widely accepted for clinical staging as a guide to operability and prognosis. We report on a consecutive retrospective series of 110 patients undergoing mediastinoscopy between 1982-1986 for primary mediastinal lymphadenopathy in order to assess the diagnostic value and safety of the procedure. Mediastinoscopy gave a positive histological diagnosis in 74.5% of cases with no false negative results. There were no deaths and one complication only (pneumothorax). This study shows mediastinoscopy to be a safe, accurate and cost effective procedure minimising hospital stay and allowing appropriate treatment to be immediately commenced upon diagnosis. Mediastinoscopy obviates the need for expensive computed tomography or nuclear magnetic resonance scans and we conclude that it is the investigation of choice for primary mediastinal lymphadenopathy after confirmation by plain chest radiography.

An essential SMN interacting protein (SIP1) is not involved in the phenotypic variability of spinal muscular atrophy (SMA)

The survival motor neuron (SMN) protein and the SMN interacting protein 1 (SIP1) are part of a 300 kD protein complex with a crucial role in snRNP biogenesis and pre-mRNA splicing. Both proteins are colocalised in nuclear structures called gems and in the cytoplasm. Approximately 96% of patients with autosomal recessive spinal muscular atrophy (SMA) show mutations in the SMN1 gene, while about 4% fail to show any mutation, despite a typical SMA phenotype. Additionally, sibs with identical 5q13 homologs and homozygous absence of SMN1 can show variable phenotypes which suggest that SMA is modified by other, yet unknown factors. Since both genes, SMN1 and SIP1, belong to the same pathway and are part of the same protein complex, it is obvious to ask whether mutations within SIP1 are responsible for both the phenotypic variability and the appearance of non-SMN mutated SMA patients. First, we identified the chromosomal location of SIP1 and assigned it to chromosomal region 14q13-q21 by fluorescence in situ hybridisation. No SMA related disorder has yet been assigned to this chromosomal region. Next, we determined the exon-intron structure of the SIP1 gene which encompasses 10 exons and identified five transcription isoforms. We sequenced either RT-PCR products or genomic DNA covering the complete coding region from 23 typical SMA patients who had failed to show any SMN1 mutation. No mutation and no polymorphism was found within SIP1. Additionally, we sequenced RT-PCR products or genomic fragments of the entire SIP1 coding region from 26 sibs of 11 SMA families with identical genotypes (delta7SMN/delta7SMN or delta7SMN/other mutation) but different phenotypes and again no mutation was found. Finally, we performed quantitative analysis of RT-PCR products from the same 26 sibs. No difference in expression level of the five isoforms among phenotypically variable sibs was observed. Based on these data, we suggest that neither the phenotypic variability nor the 5q-unlinked SMA are caused by mutations within SIP1.

Phase- and size-adjusted CT cut-off for differentiating neoplastic lesions from normal colon in contrast-enhanced CT colonography

A computed tomography (CT) cut-off for differentiating neoplastic lesions (polyps/carcinoma) from normal colon in contrast-enhanced CT colonography (CTC) relating to the contrast phase and lesion size is determined. CT values of 64 colonic lesions (27 polyps <10 mm, 13 polyps > or =10 mm, 24 carcinomas) were determined by region-of-interest (ROI) measurements in 38 patients who underwent contrast-enhanced CTC. In addition, the height (H) of the colonic lesions was measured in CT. CT values were also measured in the aorta (A), superior mesenteric vein (V) and colonic wall. The contrast phase was defined by xA + (1-x)V using x as a weighting factor for describing the different contrast phases ranging from the pure arterial phase (x=1) over the intermediate phases (x=0.9-0.1) to the pure venous phase (x=0). The CT values of the lesions were correlated with their height (H), the different phases (xA+(1-x)V) and the ratio [xA+(I-x)V]/H. The CT cut-off was linearly adjusted to the imaged contrast phase and height of the lesion by the line y=m[xA+(1-x)V]H+y(0). The slope m was determined by linear regression in the correlation (lesion approximately [xA+(i-x)V]/H) and the Y-intercept y(0) by the minimal shift of the line needed to maximize the accuracy of separating the colonic wall from the lesions. The CT value of the lesions correlated best with the intermediate phase: 0.4A + 0.6V (r=0.8 for polyps > or =10 mm, r=0.6 for carcinomas, r=0.4 for polyps <10 mm). The accuracy in the differentiation between lesions and normal colonic wall increased with the height implemented as divisor, reached 91% and was obtained by the dynamic cut-off described by the formula: cut-off (A,V,H)=1.1 [0.4A+0.6V]/H+69.8. The CT value of colonic polyps or carcinomas can be increased extrinsically by scanning in the phase in which 0.4A + 0.6V reaches its maximum. Differentiating lesions from normal colon based on CT values is possible in contrast-enhanced CTC and improves when the cut-off is adjusted (normalized) to the contrast phase and lesion size.

Staging des Prostatakarzinoms: Wertigkeit der kombinierten Information aus endorektaler MRT, bioptischem Gleason Score und präoperativem PSA-Wert

PURPOSE

To evaluate the predictive value of MR imaging criteria, the biopsy Gleason score, and preoperative PSA levels for differentiating between T2 and T3 prostate carcinomas.

MATERIALS AND METHODS

Endorectal MR images of 81 patients (median age: 65 years, range: 48 to 81 years) who had biopsy-proven prostate cancer and underwent a radical prostatectomy were analyzed retrospectively. The existence of different imaging features were recorded for each patient. A radiological analysis comprising all used imaging criteria was also performed for every patient. Optimal cut-off levels for the biopsy Gleason score and preoperative PSA levels were obtained using ROC analyses. Subsequently, a logistic regression analysis was performed to identify features which make a significant contribution to the prediction of the tumor stage.

RESULTS

Histological examination showed that 24 patients (29.6 %) had a T3 tumor and 57 patients (70.4 %) had a T2 tumor. The mean preoperative PSA level was 9.4 ng/ml (+/- 7 ng/ml), and the median Gleason score was 6 with a range of 4 to 8. The radiological judgment comprising all imaging criteria led to a sensitivity of 54.2 % and specificity of 79 % for the detection of a T3 tumor. The obliteration of the rectoprostatic angle (regression coefficient B = 2.30; standard error (se) = 0.80; p = 0.002) and the biopsy Gleason score (B = 1.16; se = 0.3; p = 0.001) were the parameters with the highest independent predictive value for the diagnosis of an extracapsular tumor spread. The other radiological criteria and the preoperative PSA level were not statistically significant. A combination of the parameters "obliteration of the rectoprostatic angle" and "biopsy Gleason score" led to a sensitivity and specificity of 75 % and 79 %, respectively (existence of one parameter sufficient). The optimal cut-off value was a Gleason score of 7 for the differentiation between T2 and T3 prostate carcinomas.

CONCLUSION

In our study, only the criteria "obliteration of the rectoprostatic angle" and "biopsy Gleason score" were of predictive value for the diagnosis of a T3 prostate carcinoma. The other MR imaging criteria and the preoperative PSA levels had no additional benefit.

MR-guided biopsies with a newly designed cordless coil in an open low-field system: Initial findings

The purpose of this study was to examine the feasibility and safety of MR-guided biopsies with a newly designed cordless coil in an open low-field magnetic resonance (MR) system. Eleven patients were biopsied using a low-field system (0.2 T, Magnetom Concerto, Siemens) by using the new cordless coil (Siemens). The biopsies were performed in different organ systems [liver (n = 7), abdomen (n = 1), shoulder (n = 1), pelvis (n = 1) and hip (n = 1)]. The procedures were guided using T1-weighted FLASH (fast low-angle shot) sequences. The lesions were biopsied using the coaxial technique through a 15-gauge puncture needle with a 16-gauge biopsy handy. Coil handling, image quality and complications were evaluated. Imaging quality and visualization of the lesions were optimal up to a penetration depth of 9 cm. In all cases the biopsy procedures were successfully performed with MR guidance without any complications. Pathological findings revealed seven cases of malignant tissue and four cases of non-malignant tissue. The use of the cordless coil allows improved patient access during the biopsy and an improved handling of the coil system. MR-guided biopsy using the novel cordless coil system can be performed safely and precisely with easy handling of the coil. This coil concept, however, is restricted to special indications.

[Nucleolysis in the herniated disk]

Back pain associated with a herniated disk has become an important and increasing general health problem in Germany and other industrialized countries. After all methods of conservative treatment have been exhausted, nucleolysis may be a minimally invasive alternative to surgery. In nucleolysis, chondrolytic substances or other substances, which reduce the pressure within the disk by other means, are injected into the nucleus pulposus under CT guidance. Among various substances, which have been employed for nucleolysis, an ozone-oxygen mixture appears to be very promising. The water-binding capacity of ozone results in a reduction of pain for several months. Moreover, it has an anti-inflammatory effect and results in an increase of perfusion. Ozone is converted into pure oxygen in the body and has a low allergic potential. Recent minimally invasive therapeutic methods such as percutaneous nucleotomy or laser treatment do not result in superior results compared with nucleolysis.

Treatment of middle cerebral artery occlusion and internal carotid artery dissection with combined mechanical thrombectomy and stenting of the internal carotid artery. A case report

We describe a case of combined mechanical thrombectomy of the right middle cerebral artery and stent angioplasty of the right internal carotid artery in a severe stroke caused by arterio-arterial embolism due to a traumatic dissection of the internal carotid artery. The patient was admitted with an NIHSS score of 19 and was discharged from hospital with a score of 2. Three months later neurological examination disclosed no pathological findings. The case demonstrates the crucial role of interventional procedures in the treatment of severe stroke where intravenous thrombolysis has little prospect of success.

[Variation in X-ray dose quantity using an amorphous selenium based flat-panel detector -- a study on the dose reduction rate up to the limit of diagnostical utilization]

PURPOSE

To evaluate the diagnostic quality and minimum required dose to obtain acceptable images for diagnostic purposes in the field of musculoskeletal radiology.

MATERIALS AND METHODS

A critical comparison of the image quality produced by a novel flat panel detector and the conventional screen/film system using a contrast-detail phantom was performed in phase I. Images from both systems were obtained with the same dose and displayed with similar contrast and density. In phase II images of significant anatomical structures in cadaver extremities obtained using the digital detector system and the standard film/screen system were critically evaluated. After a successive reduction in the X-ray dose for 84 patients in phase III, eight independent radiologists compared the image quality of the screen/film system to that of the novel flat panel detector.

RESULTS

Phases I and II revealed a difference in the image quality achieved by the standard screen/film system and the digital detector system to the advantage of the digital detector system. In 77 of 84 patients (91.7 %), phase III showed equal image quality after a 50 % reduction in the X-ray dose. In 3 cases (3.6 %) the image quality and the level of contrast were better. No unified statement could be made for 4 patients (4.7 %).

CONCLUSION

Digital imaging of skeletal disorders using the novel flat panel detector makes it possible to reduce the X-ray dose by 50 % with equal or even better image quality.

[Efficacy of x-ray assessment in emergency surgical departments: an evaluation in a level I trauma center]

BACKGROUND

The aim of the study was to ascertain the state of the art in x-ray assessment in an emergency surgical department.

METHODS

From August 2008 to February 2009 a total of 1,588 plain x-rays of 658 patients from the emergency department were included in this study. The images were assessed by 3 experienced orthopedic surgeons and 1 experienced radiologist. The incidence of missed traumatic lesions and suspected lesions and the treatment of these patients were noted.

RESULTS

A total of 136 pathological cases with 238 pathological x-ray findings were found. The mean rate of missed lesions was 13% of the assessed cases. Despite the fact that the rate of missed lesions varied from 9-25% depending on the level of experience, all patients were treated adequately. The quality of x-ray assessment improved with the level of training of the individual doctors.

CONCLUSION

The present situation is in need of improvement but it is not critical. Junior medical staff should undergo a special training in x-ray assessment.