gagCEST imaging at 3 T MRI in patients with articular cartilage lesions of the knee and intraoperative validation.

OBJECTIVE: The aim of this study was to compare glycosaminoglycan chemical exchange saturation transfer (gagCEST) of knee cartilage with intraoperative results for the assessment of early osteoarthritis (OA) and to define gagCEST values for the differentiation between healthy and degenerated cartilage. DESIGN: Twenty-one patients with cartilage lesions or moderate OA were examined using 3 T Magnetic Resonance Imaging (MRI). In this prospective study, regions of interest (ROIs) were examined by a sagittal gagCEST analysis and a morphological high-resolution three-dimensional, fat-saturated proton-density space sequence. Cartilage lesions were identified arthroscopically, graded by the International Cartilage Repair Society (ICRS) score in 42 defined ROIs per patient and consecutively compared with mean gagCEST values using analysis of variance and Spearman's rank correlation test. Receiver operating characteristics (ROC) curves were applied to identify gagCEST threshold values to differentiate between the ICRS grades. RESULTS: A total of 882 ROIs were examined and graduated in ICRS score 0 (67.3%), 1 (25.2%), 2 (6.2%) and the merged ICRS 3 and 4 (1.0%). gagCEST values decreased with increasing grade of cartilage damage with a negative correlation between gagCEST values and ICRS scores. A gagCEST value threshold of 3.55% was identified to differentiate between ICRS score 0 (normal) and all other grades. CONCLUSIONS: gagCEST reflects the content of glycosaminoglycan and might provide a diagnostic tool for the detection of early knee-joint cartilage damage and for the non-invasive subtle differentiation between ICRS grades by MRI even at early stages in clinical practice.

Intraoperative validation of quantitative T2 mapping in patients with articular cartilage lesions of the knee.

OBJECTIVE: The aim of this study was to compare T2 relaxation times of knee cartilage with intraoperative results for the assessment of early osteoarthritis (OA) and to define T2 values for the differentiation between healthy and degenerated cartilage. DESIGN: Twenty-one patients with cartilage lesions or moderate OA were examined using 3T magnetic resonance imaging (MRI). In this prospective study, a total of 882 regions of interest (ROIs) were examined by a sagittal, multi-echo, spin-echo T2 sequence and a morphological high-resolution three-dimensional, fat-saturated proton-density space sequence. Cartilage lesions were identified arthroscopically, graded by the International Cartilage Repair Society (ICRS) score in 42 defined ROIs per patient and consecutively compared with mean T2 values using analysis of variance and Spearman's rank correlation test. Receiver operating characteristics (ROC) curves were developed to identify threshold T2 values to differentiate between the ICRS grades. RESULTS: A total of 882 ROIs were examined and graduated in ICRS score 0 (67.3%), 1 (25.2%), 2 (6.2%) and the merged ICRS 3 and 4 (1.0%). T2 values increased with increasing grade of cartilage damage with a statistically significant positive correlation between T2 values and ICRS scores. A T2 value threshold of 47.6 ms was identified to differentiate between ICRS score 0 (normal) and all other grades (ROC curve analysis). CONCLUSION: T2 mapping might provide a diagnostic tool for the detection of early knee-joint cartilage damage and for the non-invasive differentiation between ICRS grades by MRI in clinical practice.

[The utilization of MRI by orthopaedic surgeons: requirements and limitations]. / Fachbezogene Anwendung der MRT in Orthopädie und Unfallchirurgie: Voraussetzungen und Limitationen.

BACKGROUND: The tendency in surgical fields to subspecialize continues. Diagnostic possibilities and surgical indications are becoming more and more sophisticated. As a consequence, surgeons in Germany have the possibility to acquire qualifications in magnetic resonance imaging (MRI) and are allowed to employ MRI scanners without consulting radiologists. AIMS: This article aims to describe the requirements to achieve this special qualification and to give a summary on the legal issues in this matter.

[EUROCRINE®: adrenal surgery 2015-2019- surprising initial results]. / EUROCRINE®: Nebennierenoperationen 2015 bis 2019 ­ überraschende erste Ergebnisse.

BACKGROUND: Since 2015 operations performed in the field of endocrine surgery have been entered into the European registry EUROCRINE®. The aim of this analysis was a description of the current healthcare situation for adrenal surgery in a homogeneous healthcare environment corresponding to the German-speaking countries-or to the presence of the working group on surgical endocrinology (CAEK) of the German society for general and visceral surgery (DGAV)-and to assess the adherence to current international treatment guidelines. METHODS: An analysis of the preoperative diagnostics, the applied operative techniques and the underlying histological entities was carried out for all operations on adrenal glands in Germany, Switzerland and Austria, which were registered in EUROCRINE® from 2015 to 2019. RESULTS: In the total of 21 participating hospitals from the German-speaking EUROCRINE® countries, 658 operations on adrenal glands were performed. In 90% of cases unilateral adrenalectomy was performed, in 3% bilateral adrenalectomy and in 7% other resection procedures. In 41% the main histological diagnosis was an adrenocortical adenoma. In 15% malignant entities were detected on final histology, including 6% adrenocortical carcinoma (ACC) and 8% metastases to the adrenal glands. 23% of the operations were performed for pheochromocytoma. This entity was primarily resected using minimally invasive approaches (82%), whereas minimally invasive techniques were applied in 28% for ACC and in 66% for metastases to the adrenal glands. CONCLUSION: Surprisingly, following adrenocortical adenoma and pheochromocytoma, the third most common histological entity was metastasis of different extra-adrenal primary tumors to the adrenal gland. Of the operations for ACC 28% were scheduled for minimally invasive techniques, but conversion to open surgery was necessary in 20%. The analysis revealed discrepancies between treatment reality and international guideline recommendations that raise questions, which will be addressed by an updated version of the EUROCRINE® module for the documentation of adrenal surgery.

Intraoperative thoracic epidural anaesthesia attenuates stress-induced immunosuppression in patients undergoing major abdominal surgery.

BACKGROUND: Intraoperative stress may suppress the adaptive immune system. Abolished proinflammatory lymphocyte function is associated with higher risk of infection and postoperative complications. We hypothesized that thoracic epidural anaesthesia (TEA) reduces intraoperative stress and thus attenuates lymphocyte decrease and impairment of proinflammatory lymphocyte function. METHODS: Fifty-four patients undergoing major abdominal surgery who had a thoracic epidural catheter inserted were studied. In the TEA-I group, this catheter was used for intraoperative analgesia, whereas the TEA-P group received systemic opioids during surgery. In both groups, patient-controlled epidural analgesia was used for postoperative pain management. Blood samples for immune analyses were obtained before induction of anaesthesia, 2 h after skin incision, and at days 1 and 4 after surgery. Lymphocyte subpopulations, expression of human leucocyte antigen (HLA)-DR on monocytes, plasma concentrations of interleukin (IL)-10, interferon-gamma (IFN-gamma), and IL-12, and concanavalin-A-stimulated concentrations of IFN-gamma and IL-10 were measured. Intraoperative data including bispectral index and plasma concentrations of epinephrine/cortisol were analysed; APACHE-II, SAPS II, and additional postoperative data were documented. RESULTS: Plasma concentrations of epinephrine and cortisol were significantly lower in the TEA-I patients during surgery. IFN-gamma/IL-10 ratio was significantly higher in the TEA-I group from 2 h after skin incision until day 1. Lymphocyte numbers and T-helper cells were significantly higher in the TEA-I group at day 1, whereas no significant differences were detected among IL-12, HLA-DR, and postoperative clinical course. CONCLUSIONS: Intraoperative use of thoracic epidural catheter reduced stress response and prevented stress-induced perioperative impairment of proinflammatory lymphocyte function.

Prevalence of neurovascular compression in patients with essential and secondary hypertension.

AIMS: There are discrepant data on the prevalence of vascular compression of the rostral ventrolateral medulla, discussed as a possible cause of essential hypertension, in patients with essential and secondary hypertension. We therefore evaluated the comparative prevalence of neurovascular compression in two large and well defined patient groups with severe essential and secondary hypertension. PATIENTS AND METHODS: 121 patients with long-standing severe (requiring at least three antihypertensive agents for adequate control of blood pressure) essential or secondary hypertension and extensive examination for causes of secondary hypertension were recruited. The presence of neurovascular compression was assessed independently by a neuroradiologist and a neurosurgeon in MRI images for all patients. The subgroup of patients with the highest prevalence of neurovascular compression was identified by CART-analysis. RESULTS: 5 of 121 formerly included patients (4.1%) were excluded for diverging MRI assessments. Neurovascular compression was diagnosed in 50 of 68 patients (73.5%) with essential hypertension and 6 of 48 patients (12.5%) with secondary hypertension. The odds ratio for diagnosis of neurovascular compression in patients with essential hypertension was 19.4 (95%-confidence interval 7.9-47.9) compared to patients with secondary hypertension. CART-analysis identified the highest prevalence of neurovascular compression in patients with severe essential hypertension younger than 67.5 years. CONCLUSIONS: Since successful decompression or implantation of a carotid sinus stimulator in patients eligible for surgery may lead to substantial improvement in blood pressure in patients in whom blood pressure could not be lowered below 140/90 mmHg by antihypertensive treatment alone MRI screening for the presence of neurovascular compression is justified in patients meeting all of the following three criteria: exclusion of secondary hypertension after extensive examination; hypertension uncontrollable with antihypertensive treatment alone, and age younger than 67.5 years.

Betaine use by rhizosphere bacteria: genes essential for trigonelline, stachydrine, and carnitine catabolism in Rhizobium meliloti are located on pSym in the symbiotic region.

Rhizobium meliloti is known to use betaines synthesized by its host, Medicago sativa, as osmoprotectants and sources of energy. It is shown in the present report that the symbiotic megaplasmid (pSym) of R. meliloti RCR2011 encodes functions essential to the catabolism of three betaines, trigonelline (nicotinic acid N-methylbetaine), stachydrine (proline betaine or dimethylproline), and carnitine (gamma-trimethyl-beta-hydroxybutyrobetaine). Preliminary evidence is presented showing that functions on pSym also influence the catabolism of choline and its oxidative product, glycine betaine. Genes implicated in betaine catabolism are found in the symbiotic region of pSym. Trigonelline catabolism functions lie between two clusters of symbiotic genes, nifKDH and nok/fixVI'. Stachydrine and carnitine functions lie to the right of trigonelline catabolism functions, immediately to the right of fixVI'. Information necessary to choline and glycine betaine catabolism is probably encoded to the right of stachydrine catabolism functions.

The stachydrine catabolism region in Sinorhizobium meliloti encodes a multi-enzyme complex similar to the xenobiotic degrading systems in other bacteria.

Stachydrine (proline betaine) can be used by Sinorhizobium meliloti as a source of carbon and nitrogen. Catabolism depends on an initial N-demethylation, after which the resultant N-methyl proline enters general metabolism. Deletion and insertion mutagenesis demonstrated that the information necessary for catabolism is carried on the symbiotic plasmid (pSym) distal to nodD2 and the nod-nif cluster. Sequencing of an 8.5kb fragment spanning this region revealed four open reading frames with functional homology to known proteins, including a putative monooxygenase and a putative NADPH-FMN-reductase, which were shown by insertional and frame-shift mutagenesis to be necessary for stachydrine catabolism. Other open reading frames, encoding a putative flavoprotein and a repressor, were judged not to be required for stachydrine catabolism, since they were not included in a fragment capable of complementing a deletion of the entire stc region. Sequence and mutagenesis data suggest that stachydrine is demethylated by an iron-sulfur monooxygenase of the Rieske type with a requirement for a specific reductase. The stc catabolic cluster, therefore, resembles xenobiotic degradation in other bacteria and recalls rhizopine catabolism in S. meliloti. Stachydrine appears to have multiple roles in osmoprotection, nutrition and nodulation. Genes involved in stachydrine catabolism are also necessary for carnitine degradation; thus, they could be important in the catabolism of a variety of root exudates and mediate other relationships.

Left main coronary artery stenosis following mediastinal irradiation.

The association of mediastinal radiation therapy and coronary artery disease has been documented over the past three decades. This report describes a case of left main coronary artery stenosis eight years after radiation therapy in a 27-year-old woman. The patient was a young woman with no risk factors for coronary artery disease who had development of new-onset angina at rest. At coronary arteriography, the patient was found to have a tight ostial left main stenosis. The association of mediastinal radiation therapy with fixed and vasospastic coronary artery disease is reviewed. With many patients treated by radiation therapy now surviving their thoracic malignancies, an enlarging young population may be susceptible to the early development of ischemic heart disease.

Preoperative versus postoperative radiotherapy for prevention of heterotopic ossification (HO): first results of a randomized trial in high-risk patients.

PURPOSE: In vivo data support the effectiveness of pre- and postoperative radiotherapy in suppressing the development of heterotopic ossification after hip surgery. In June 1992 a prospectively randomized trial was initiated to assess the comparative efficacy of pre- vs. postoperative prophylactic radiotherapy in patients with high risk to develop heterotopic ossification after hip surgery. METHODS AND MATERIAL: Between June 1992 and September 1993 a total of 84 eligible patients with high risk profile for the development of heterotopic ossification were entered in the study. They were randomized to receive radiotherapy either preoperatively (< 4 h before surgery) or according to a "standard protocol" postoperatively (< 72 h after surgery). A single 7 Gy fraction was administered to the preoperative group, while the postoperative group received a previously tested scheme of five fractions of 3.5 Gy (total dose 17.5 Gy). The treatment portal encompassed the soft tissues between the periacetabular region of the pelvis and the intertrochanteric portion of the femur. Important patient variables (age, sex, prior surgery) and predisposing risk factors were equally distributed between both treatment arms. X rays of the irradiated hips were obtained prior and immediately after surgery as well as at 6 months after surgery. The modified Brooker grading was used to score the extent of heterotopic ossification. The Harris score was applied to judge the overall functional status of the hip. If the Brooker grade and Harris score decreased from the immediate postoperative or preoperative status respectively to the follow-up situation, the case was considered as a "treatment failure." RESULTS: At a minimum 6 months follow-up after hip surgery 44 patients were available for evaluation. Effective prophylaxis was achieved in 41 (93%) hips. Two "radiological failures" were observed in the preoperative group and one in the postoperative group. Neither the pre- nor the postoperative interval affected the prophylactic efficacy. There were no increased intra- and postoperative complications seen in the preoperative group. The interval of partial strain (50% body weight) to the operated hip was longer in the preoperative group (19 days +/- 27) as compared to the postoperative group (8 days +/- 13), however the interval to full strain (100% body weight) was equal in both groups. The functional status (Harris Score change) of the operated hip decreased only in two (5%) patients ("functional failures"). The overall change was better in the postoperative group (42.7 +/- 17.1) as compared to the preoperative group (34.3 +/- 13.7) (p = 0.08, NS) as well as with regard to the criteria "limp" (p = 0.05) and "use of walking support" (p = 0.10, NS). In in all other aspects no differences were observed between both treatment arms. Therefore, the preliminary results for preoperative radiotherapy are similar to historical results obtained with postoperative radiotherapy regimens. CONCLUSION: Preoperative radiotherapy of the operative site applied within 4 h prior to elective hip surgery and total hip arthroplasty appears to be equally effective to currently accepted postoperative radiotherapy regimens in prevention of clinically significant heterotopic ossification about the hip. Improved patient comfort, ease of treatment management, and avoidance of possible postoperative complications associated with moving and positioning the patient in the immediate postoperative period are the major advantages of the preoperative radiotherapy concept.

Prevention of heterotopic ossification about the hip: final results of two randomized trials in 410 patients using either preoperative or postoperative radiation therapy.

PURPOSE: Experimental and clinical data support effectiveness of perioperative radiotherapy to prevent heterotopic ossification after hip surgery or trauma. Since 1987, two prospectively randomized trials were performed in patients with high-risk factors to develop heterotopic ossification: the first (HOP 1) to assess the prophylactic efficacy of postoperative low vs. medium dose radiotherapy, and the second (HOP 2) to assess the prophylactic efficacy of pre vs. postoperative radiotherapy. METHODS AND MATERIAL: 410 patients with high risk to develop heterotopic ossifications about the hip following hip surgery were recruited. Between June 1987 and June 1992, 249 patients were randomized in HOP 1 to postoperative "low dose" (5 x 2 Gy; total: 10 Gy) or "medium dose" (5 x 3.5 Gy; total: 17.5 Gy) radiotherapy. Between July 1992 and December 1995, 161 patients were randomized in HOP 2 to either 1 x 7 Gy preoperatively (< or = 4 h before surgery) or 5 x 3.5 Gy (total: 17.5 Gy) postoperatively (< or = 96 h after surgery). With exception of age and type of implant (cemented vs. uncemented prosthesis) all confounding patient variables (gender, prior surgery) and predisposing risk factors were similarly distributed between both trials and treatment arms. Portals encompassed the periacetabular and intertrochanteric soft tissues. Radiographs were obtained prior and immediately after surgery and at least 6 months after surgery to assess the extent of ectopic bone formation about the hip. Modified Brooker grading was used to score the extent of heterotopic ossification. Harris scoring was applied to evaluate the functional hip status. If the scores decreased from immediate post or preoperative status, respectively, to the last follow-up, radiological or functional failures were assumed. RESULTS: Effective prophylaxis was achieved in 227 (91%) hips of HOP 1 and in 142 (88%) of HOP 2. In HOP 1, 15 (11%) radiological failures were observed in the low-dose group compared to 7 (6%) in the medium dose group (p > 0.05). In HOP 2, 4 (5%) radiological failures were observed in the postoperative and 11 (19%) in the preoperative group (p < 0.05). Subgroup analysis of the preoperative group revealed that the highest failure rate occurred in patients with prophylactic radiotherapy prior to removal of ipsilateral Brooker Grade III and IV ossification (39%) (p < 0.001), while all other patients in the preoperative group had a failure rate that was comparable to postoperative treatment groups. In multivariate logistic regression analysis the number of high-risk factors for development of heterotopic ossification (p = 0.03) and the time to RT initiation (p = 0.05) were independent prognostic factors in the HOP 1 study. For the HOP 2 study, the multivariate logistic regression analysis revealed the number of high-risk factors for development of heterotopic ossification (p = 0.003), the preoperative HO grade (p = 0.001) and the RT dose concept (p = 0.05) as independent prognostic factors. Other factors including type of implant (cemented vs. uncemented) did not affect the prophylactic efficacy of radiotherapy. There were no increased intra- and postoperative complications seen in the preoperative group, and no long-term complications were observed in both HOP studies. For functional failures (decrease of Harris score) no statistically prognostic factors were found. There were less functional failures in HOP 1 (18 = 7%) than in HOP 2 (23 = 14%, but this difference was not statistically significant. Only patients with high Brooker Grade III and IV at last FU achieved a lower Harris score than those with low Brooker Grade 0, I and II (p < 0.05). CONCLUSION: With the exception of a small subgroup of patients with ipsilateral high Brooker Grade III and IV, pre- and postoperative radiotherapy are equally effective to prevent heterotopic ossification about the hip after hip surgery and total hip arthroplasty. Fractionated medium dose radiotherapy resulted in the low

Impact of simple screening criteria on utilization of low-yield bacterial stool cultures in a Children's Hospital.

OBJECTIVE: To determine diagnostic yield of stool cultures for Salmonella, Shigella, Campylobacter jejuni, Yersinia enterocolitica, and Escherichia coli O157:H7 (SSCYE) among hospitalized children and to develop guidelines for appropriate use of these tests. Setting. Tertiary care pediatric hospital. DESIGN: Computerized records from the Microbiology Laboratory from January 1992 to December 1996 were reviewed retrospectively to collect data on the number of stool cultures performed in inpatients and outpatients, the length of hospital stay at the time cultures were sent, and diagnostic yield of cultures in hospitalized patients. A detailed review of medical records of all patients with a stool pathogen isolated after 3 days of hospitalization was also undertaken. The results from this retrospective analysis were used to develop guidelines to reduce unwarranted stool cultures and to educate medical care providers in the appropriate use of these tests. The impact of these guidelines on reduction in the volume of stool cultures performed on hospitalized patients was measured prospectively from January 1998 to June 1998. RESULTS: A total of 27 110 stool cultures for SSCYE were performed in the 5-year study period. Of the 14 125 cultures from inpatients, 174 (1.2%) were positive. Among the cultures from inpatients, 9378 (66%) were from patients hospitalized for >3 days. Only 13 (.14%) were positive. Of these 13 cultures, 4 represented nosocomial infections, whereas the remaining 9 cultures either were sent to document clearance from a patient known previously to be infected with an enteric pathogen (7), or were attributed to delayed testing in individuals admitted with a diarrheal illness (2). Introduction of guidelines to reject all SSCYE cultures from patients hospitalized for >3 days who did not meet specified criteria was associated with an overall reduction of 689 (43%) in the volume of tests performed in the 6-month period evaluated. This included 497 fewer cultures ordered and 192 cultures that were ordered but rejected because screening criteria were not met. Only 11 (5.4%) of 203 cultures sent >3 days after admission were processed because they met clinical criteria for testing. None were positive. Estimated cost savings were $50 163/year. CONCLUSIONS: Stool cultures for SSCYE among hospitalized patients have very low diagnostic yield and are extremely overutilized. Simple guidelines, such as rejecting (with few exceptions) cultures from patients hospitalized for >3 days, can reduce substantially such unnecessary testing.

Prevention of heterotopic ossification (HO) after total hip replacement: randomized high versus low dose radiotherapy.

In a prospectively randomized study 60 hips at high risk for heterotopic ossification (HO) received prophylactic radiotherapy (RT). Randomization was performed between a low dose (LD-RT) of 5 x 2 Gy (arm A: 32 patients) and a high dose (HD-RT) of either 10 x 2 Gy (arm B1; 8 patients) or 5 x 3.5 Gy (arm B2; 20 patients). Relevant patient and risk factors were equally distributed in both treatment arms. 4 (7%) patients developed treatment failures. A short delay of RT after postoperative day (POD) 4 was significantly correlated with failure (p < 0.001). The results suggest no difference in prophylactic efficacy between LD-RT and HD-RT treatment. 2/19 (11%) patients receiving additional diphosphonates and 2/18 (11%) on no medication failed RT treatment, but none on indomethacin did so. In conclusion, immediate postoperative RT has been shown to be an effective prophylactic treatment.

Direct operations for the management of life-threatening ischemic ventricular tachycardia.

UNLABELLED: Between June 1978 and 1986, 93 consecutive patients underwent electrophysiologically guided operations for life-threatening recurrent sustained ventricular tachycardia mostly associated with other surgical procedures, such as left ventricular resection (aneurysmectomy) and coronary artery bypass grafting. DATA: Eighty-seven percent of the surviving patients were free of spontaneous ventricular tachycardia return or sudden death 1 year after the operation and 77% at 5 years. The instantaneous risk of ventricular tachycardia return was highest immediately after operation, declined rapidly, and by 2 weeks postoperatively had merged with the constant hazard phase, which persisted as long as the patients were observed. Endocardial resection, rather than encircling endocardial myotomy, increased the risk of spontaneous ventricular tachycardia return/sudden death. Survival rates, including hospital deaths, were 95% at 30 days, 89% at 1 year, and 70% at 5 years after operation. The most prevalent mode of death was heart failure. The absence of anterolateral left ventricular aneurysms and the use of more extended encircling incisional techniques for ventricular tachycardia ablation increased the risk of early and late death. Survival was particularly poor in that subset of patients in whom recurrent sustained ventricular tachycardia returned after operation; the most prevalent mode of death in this group was also progressive left ventricular failure. Inferences: (1) Complete and partial encircling endocardial myotomy incisions are the most effective surgical techniques for malignant ventricular tachycardia ablation. (2) Because of their adverse effects on left ventricular structure and function, the arrhythmogenic tissues have to be localized as precisely as possible, and the encompassing incisions should be kept as limited as possible. (3) The late return of ventricular tachycardia may be more related to a progressive ischemic left ventricular cardiomyopathy than to an inadequate operation.

Decay times of surface plasmon excitation in metal nanoparticles by persistent spectral hole burning

We describe a new technique to determine the homogeneous linewidths of surface plasmon resonances of metal nanoparticles and thus measure the decay time of this collective electron excitation. The method is based on spectral hole burning and has been applied to supported oblate Ag particles with radii of 7.5 nm. From the experimental results and a theoretical model of hole burning the linewidth of 260 meV corresponding to a decay time of 4.8 fs was extracted. This value is shorter than expected for damping by bulk electron scattering. We conclude that additional damping mechanisms have been observed and reflect confinement of the electrons in nanoparticles with sizes below 10 nm.

Image artifacts in fast magnetic resonance imaging.

Image artifacts are unwanted, spurious signal intensities that interfere with clinical diagnosis. This article gives an overview of image artifacts in magnetic resonance imaging. We discuss the causes of these artifacts, provide clinical examples, and offer solutions to avoid them.

[Magnetic resonance tomographic imaging of pulsatile CSF movement in communicating hydrocephalus before and after shunt placement]. / Magnetresonanztomographische Darstellung der Liquorpulsbewegung bei Hydrozephalus communicans vor und nach Shuntanlage.

16 patients with hydrocephalus communicans and 5 healthy volunteers were examined to demonstrate the pattern of the pulsatile CSF flow. After implantation of a CSF shunt system the same patients were examined again to show the influence of the shunt on the CSF pulsations. We used a flow-sensitised, cardiac-gated 2D FLASH sequence and analysed the phase and magnitude images. It could be shown that most patients (n = 12) had a hyperdynamic pulsatile flow preoperatively. After shunt implantation the pulsatile CSF motion and the clinical symptoms were improved in 8 of these patients. MRI of pulsatile CSF flow movement seems to be a helpful noninvasive tool to estimate the prognosis of a shunt implantation in patients with hydrocephalus communicans.

[Magnetic resonance tomography of the liver with TurboFLASH and segmented acquisition. Fast imaging with flexible image contrast]. / Magnetresonanztomographie der Leber mit TurboFLASH und segmentierter Akquisition. Schnelle Bildgebung mit variablem Bildkontrast.

The value of a fast imaging sequence in diagnosing focal liver lesions was assessed in 43 patients. The sequence (TurboFLASH with segmented acquisition) allows the acquisition of T1- and T2-weighted images within a breath-hold interval. Lesion-liver contrast was compared with T2-weighted spin-echo, T1-weighted gradient-echo, and single shot TurboFLASH sequences. All lesions that were seen with the latter sequences were also visible on the segmented TurboFLASH images. Contrast on the segmented TurboFLASH images was similar to that of T2-weighted spin-echo sequences and superior to T1-weighted gradient-echo sequences. Signal of fat could be nulled at an inversion time of 10 ms, signal from liver tissue could be nulled at an inversion time of 300 ms. By minimising the liver signal, the lesions could be "highlighted". This was not possible with the other imaging sequences. The segmented TurboFLASH technique allows breath-hold imaging of the liver with arbitrary image contrast. The lesion-liver contrast is comparable to time-consuming T2-weighted spin-echo sequences.

[Stent-supported percutaneous therapy of iliac vein stenosis following operative thrombectomy and placement of a shunt]. / Stentgestützte perkutane Therapie bei Beckenvenenstenosen nach operativer Thrombektomie und Shuntanlage.

Among 15 patients with acute thrombotic disease of pelvic veins who had been submitted to operative thrombectomy and creation of arteriovenous fistula in the groin, 12 presented with stenotic lesions 3 months later. These stenoses were submitted to percutaneous angioplasty. If angioplasty failed, percutaneous placement of a vascular stent (wall stent) was performed immediately (n = 7). Stenting in cross-over-technique proved practicable in all cases. Secondary stenotic disease in the exclusively dilated area was observed in 3/5 cases and was also treated with a wall stent. In one patient with recurrent stenoses who refused stenting, extended thrombosis occurred after occlusion of the AV-fistula. At mid-term PTA was successful in only two cases. Intimal hyperplasia was observed in only one wall stent treated patient. Percutaneous treatment of iliacal stenoses in patients with postthrombotic syndrome may be performed safely under the protective effect of the fistula. With the presented technique, patency of pelvic veins could be restored in 11/12 patients with postoperative significant venous stenoses.

[The postoperative MR tomographic findings following the removal of a hypophyseal adenoma]. / Postoperative kernspintomographische Befunde nach Hypophysenadenomentfernung.

36 patients with pituitary adenomas were examined via MRI to describe physiological changes and to visualise a residual tumour. Pre- and postoperative examinations included T1- and T2-weighted SE sequences. T1-weighted images were obtained in sagittal and coronal orientation pre- and post-Gd-DTPA application and T2-weighted images in coronal orientation. In 12 cases a residual tumour was found. Its signal intensity and contrast enhancement were similar to those of the primary tumour. Implanted material could be distinguished by localisation, decrease in volume and different signal intensity. The behaviour of contrast enhancement was helpful, since implanted material showed a rim enhancement. In our experience a sensitive imaging protocol in the follow-up of operated pituitary adenomas would be an early examination three months postoperatively followed by a control examination after one year. Information on the size and localisation of the primary tumour and the performed operative procedure is essential.