Improvement in imaging common temporal bone pathologies at 3 T MRI: small structures benefit from a small field of view.

AIM: To compare image quality and evaluate its clinical importance in common temporal bone pathologies of a pTX-SPACE (parallel transmit [pTX] three-dimensional turbo spin-echo with variable flip angle [SPACE]) magnetic resonance imaging (MRI) sequence improved for spatial resolution to a standard-SPACE sequence exhibiting the same scan time at 3 T. MATERIALS AND METHODS: Thirty-four patients were examined using a standard-SPACE and resolution improved pTX-SPACE sequence at 3 T MRI. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image quality were assessed. Diseases investigated were vestibular schwannoma (VS), intralabyrinthine schwannoma (ILS), inner ear malformations, labyrinthitis, temporal bone fractures, and situation after VS resection. RESULTS: Edge definition, intratumoural pattern, discrimination of VS from the modiolus and edge definition of ILS, separability from the spiral lamina, and detectability within cochlear turns were improved on the pTX-SPACE sequence. Detectability of malformations, post-traumatic changes, and discrimination of the cochlear and facial nerve after VS resection was improved on the pTX-SPACE sequence. In labyrinthitis, pTX-SPACE was not superior to standard-SPACE. The SNR and CNR were significantly reduced for pTX-SPACE. CONCLUSIONS: pTX-SPACE significantly improves the detectability of temporal bone diseases, in particular, VS, ILS, and post-VS resection.

Zoomed EPI DWI of Acute Spinal Ischemia Using a Parallel Transmission System.

PURPOSE: A new method for diffusion-weighted imaging (DWI) using independent parallel transmission technique resulting in zoomed DWI was applied in four patients suffering from acute spinal cord ischemia. METHODS: Four patients with clinical symptoms of acute spinal cord ischemia were examined on a 3 T MR-system equipped with a two-channel transmit array. Scans included T2-weighted turbo spin echo, conventional DWI, and zoomed DWI. Image evaluation was performed with regard to overall image quality, anatomic delineation of the spinal cord, and the level of confidence to establish the diagnosis of spinal cord ischemia. RESULTS: Through spatially selective excitation, zoomed DWI allows for acquisition of high-resolution images with reduced scan time due to a reduced field of view in phase-encoding direction, resulting in zoomed images. In all cases the ischemia was demonstrated in conventional DWI as well as zoomed DWI. CONCLUSIONS: Compared to conventional DWI, zoomed DWI enables a faster image acquisition and allowed a more detailed analysis of the spinal lesion which may be critical to attribute the lesion to a particular vessel territory.

Feasibility of Noninvasive Diagnosis and Treatment Planning in a Case Series with Carotid-Cavernous Fistula using High-Resolution Time-Resolved MR-Angiography with Stochastic Trajectories (TWIST) and Extended Parallel Acquisition Technique (ePAT 6) at 3 T.

PURPOSE: The evaluation of carotid-cavernous fistulas (CCFs) and the intracranial vasculature has been predominantly carried out using conventional digital subtraction angiography (DSA). Recent developments in time-resolved magnetic resonance angiography (MRA) provide the opportunity to assess both multiple arterial and venous phases with high temporal and spatial resolution. Here, we investigated the feasibility of this technique to functionally assess CCF prior to intervention. METHODS: Six consecutive patients with clinical symptoms of a CCF were scheduled for clinically indicated MRA and underwent a protocol that comprised conventional imaging sequences and high resolution time-resolved MRA with interleaved stochastic trajectories (TWIST). The location of the fistulous communication, the flow pattern, and venous drainage were determined by time-resolved MRA and compared with DSA which was available in five out of six patients. RESULTS: Typical morphological findings (including enlargement of the superior ophthalmic vein, exophthalmos) were found in all cases in both conventional MRI and time-resolved MRA source data. The temporal resolution of time-resolved MRA enabled a good separation of the early filling of the cavernous sinus during the arterial phase. Direct fistulous communication was assessed in three patients with good correlation to DSA, whereas indirect CCF could not definitely be visualized. The time-resolved MRA provided information about the flow pattern and the venous drainage of the fistula in all patients, which is essential for therapy planning. CONCLUSION: Time-resolved MRA provides important morphological and functional information in patients with CCF. Although DSA remains the gold standard for diagnosis and exact classification of fistulas, time-resolved MRA can provide the relevant hemodynamic information to plan interventional treatment as a one-step procedure with a focused diagnostic workup.

Is the diagnostic yield of myocardial stress perfusion MRI impaired by three-vessel coronary artery disease?

BACKGROUND: Three-vessel coronary artery disease (CAD) comes along with globally reduced myocardial perfusion potentially restricting the demarcation of regional hypoperfusion in stress perfusion cardiac magnetic resonance imaging (MRI). PURPOSE: To evaluate whether stress perfusion cardiac MRI is capable of detecting myocardial hypoperfusion in patients with 3-vessel CAD reliably. MATERIAL AND METHODS: Two hundred and five patients with symptoms of CAD were included. The examination protocol comprised imaging of myocardial perfusion at stress (0.14 mg/kg/min adenosine for 4 min) using a 2D saturation recovery gradient echo sequence after administration of gadobutrol (0.1 mmol/kg body weight). Perfusion sequences were assessed qualitatively by two experienced observers. Coronary angiography served as standard of reference. RESULTS: Sensitivity and specificity for hemodynamically relevant stenoses in patients with 0-, 1-, 2-, 3-vessel coronary artery disease were 100%/91%, 91%/73%, 90%/71%, 92%/64%; positive/negative predictive value, 67%/100%, 91%/73%, 83%/81%, 93%/58%; diagnostic accuracy, 93%/87%/83%/87%, respectively. The negative predictive value in patients with 3-vessel CAD was lower than in patients with 0- and 2-vessel CAD and the specificity lower than in patients with no CAD whereas the positive predictive value was higher than in patients with no CAD. The other proportions did not differ significantly between the groups. CONCLUSION: The diagnostic value of stress perfusion cardiac MRI in patients with 3-vessel CAD is comparable to results in patients with 1- or 2-vessel CAD. In the rare event that stress perfusion images do not depict regional hypoperfusion in patients with severe 3-vessel CAD, myocardial ischemia could be identified by reduced semi-quantitative perfusion parameters.

Is myocardial stress perfusion MR-imaging suitable to predict the long term clinical outcome after revascularization?

INTRODUCTION: Aim of our study was to evaluate, whether myocardial ischemia or myocardial infarction (MI) depicted by myocardial stress perfusion MR imaging (SP CMR) can predict the clinical outcome in patients with coronary artery disease (CAD). MATERIALS AND METHOD: 220 patients were included. Myocardial perfusion was assessed at stress and at rest, using a 2D saturation recovery gradient echo sequence (SR GRE) and myocardial viability by late gadolinium enhancement magnetic resonance images (LGE CMR). MR-images were assessed in regard of presence and extent of MI and ischemia. Patients were monitored for major adverse cardiac events (MACE) (monitoring period: 5-7 years). MACE were correlated with the initial results of SP CMR. RESULTS: Ischemia was found in 143 patients, MI in 107 patients. Number of MACE was in patients with normal SP CMR 0 (51 patients), with ischemia 21 (62 patients), with MI 14 (26 patients), with ischemia and MI 52 (81 patients). In all patients with severe MACE (MI, death) and in 63 of those with recurring symptoms LGE CMR revealed MI at baseline. CONCLUSION: Negative SP CMR indicates low risk for MACE. In patients with stress induced ischemia, MACE might occur even after myocardial revascularization. The presence of MI proved by LGE CMR is associated with a significantly increased risk for MACE.

Detection of cardiovascular disease in elite athletes using cardiac magnetic resonance imaging.

PURPOSE: Sudden cardiac death [SCD] in competitive athletes is caused by a diverse set of cardiovascular diseases such as hypertrophic and dilated cardiomyopathy [HCM/DCM], myocarditis, coronary anomalies or even coronary artery disease. In order to identify potential risk factors responsible for SCD, elite athletes underwent cardiac magnetic resonance [CMR] imaging. MATERIALS AND METHODS: 73 male [M] and 22 female [F] athletes (mean age 35.2 ±â€Š11.4 years) underwent CMR imaging. ECG-gated breath-hold cine SSFP sequences were used for the evaluation of wall motion abnormalities and myocardial hypertrophy as well as for quantitative analysis (left and right ventricular [LV, RV] end-diastolic and end-systolic volume [EDV, ESV], stroke volume [SV], ejection fraction [EF] and myocardial mass [MM]). Furthermore, left and right atrial sizes were assessed by planimetry and delayed enhancement imaging was performed 10 minutes after the application of contrast agent. Coronary arteries were depicted using free-breathing Flash-3 D MR angiography. RESULTS: The quantitative analyses showed eccentric hypertrophy of the left ventricle (remodeling index [MM/LV-EDV]: M 0.75, F 0.665), enlargement of the RV volumes (RV-EDV: M 122.6 ±â€Š19.0 ml/m², F 99.9 ±â€Š7.2 ml/m²) and an increased SV (LV-SV: M 64.7 ±â€Š10.0 ml/m², F 56.5 ±â€Š5.7 ml/m²; RV-SV; M 66.7 ±â€Š10.4 ml/m², F 54.2 ±â€Š7.1 ml/m²). Abnormal findings were detected in 6 athletes (6.3 %) including one benign variant of coronary anomaly and abnormal late gadolinium enhancement in 2 cases. None of the athletes showed wall motion abnormalities or signs of myocardial ischemia. CONCLUSION: CMR imaging of endurance athletes revealed abnormal findings in more than 5 % of the athletes. However, the prognostic significance remains unclear. Thus, cardiac MRI cannot be recommended as a routine examination in the care of athletes.

p53 is correlated with low BMI negative progesterone receptor status and recurring disease in patients with endometrial cancer.

OBJECTIVE: P53 tumor suppressor gene plays a role in endometrial carcinogenesis. Former studies described correlations between p53 protein overexpression in endometrial cancer and prognostic factors, measured by immunohistochemistry. But data is still controversial. The aim of this study was to measure p53 and phospho-p53 overexpression by Western blot and evaluate correlations between overexpression and prognostic and clinical factors. Phospho-p53 seems to be the functional p53 protein and was examined for the first time in endometrial cancer. METHODS: 40 patients with endometrial cancer were included in the study. A control group of 20 patients with normal endometrial tissue samples was used. Western blot was performed for detection of p53 and phospho-p53. Clinical and pathological parameters were obtained from medical records. Statistical analysis was performed using the log-rank test, the Mann-Whitney test for two independent groups and the Fisher's exact test for dichotomous groupings. RESULTS: In 17.5% of the patients with endometrial cancer a p53 overexpression could be evaluated. There was a correlation between a p53 overexpression and recurring disease (p: 0.014), a negative progesterone receptor status (p: 0.021) and a low BMI (p: 0.022). Only one of 40 patients had a phospho-p53 expression. CONCLUSION: Western blot is a valid method for the detection of p53 overexpression. As other authors described before, p53 overexpression seems to correlate with negative prognostic factors. The correlation between p53 overexpression and a low BMI may underline the relationship between p53 alterations and biological aggressive endometrial carcinomas.

MRI for evaluation of potential living liver donors: a new approach including contrast-enhanced magnetic resonance cholangiography.

OBJECTIVES: To assess the feasibility of a comprehensive MRI protocol using intrabiliary contrast medium (gadolinium-EOB-DTPA) for evaluation of living liver donors. MATERIAL AND METHODS: In this prospective study, 30 donor candidates for living-related liver transplantation (17 men; 13 women, mean age 37 ± 10.9 years) underwent MRI including MR-angiography (MRA) as well as a conventional T2-weighted MR-cholangiography (MRC) and a contrast-enhanced sequence for depiction of the biliary structures. MRC and MRA images were evaluated for quality on a four-point-scale (score of 0 indicated poor and a score of 3, excellent image quality). Anatomic variants of the arterial, venous, portal venous, and biliary structures were identified. RESULTS: Image quality was diagnostic in all examinations except for 4 of 30 MRA data sets. Intrahepatic biliary structures, especially with regard to the intrahepatic bile ducts of 2nd and 3rd order could be identified with significantly increased image quality than in conventional T2-weighted MRC sequences (P = 0.005 and P = 0.035). A high percentage rate of anatomic variants regarding the biliary, arterial, venous, and portal venous anatomy was found. CONCLUSION: This protocol allows the evaluation of liver donors especially with regard to the biliary structures. However, the depiction of the arterial anatomy requires further technical developments.

Depiction of variants of the portal confluence venous system using multidetector row CT: analysis of 916 cases.

PURPOSE: Detailed knowledge of the venous mesenteric system is important for gastrointestinal surgery, particularly for transplantation planning and surgery and for the comprehension of perioperative complications that may influence patient outcome. Data about the mesenteric venous anatomy in the literature varies substantially. The purpose of this study was to categorize venous mesenteric variants and to determine their incidence. MATERIALS AND METHODS: We included 916 patients requiring diagnostic abdominal CT in the portal venous phase. The mesenteric vein anatomy was categorized as follows: 1. the inferior mesenteric vein (IMV) enters the splenic vein (SV); 2. the IMV enters into the angle of the confluence of the SV and superior mesenteric vein (SMV) forming the portal vein (PV); 3. the IMV enters the SMV; 4. seven rare variants. We measured the diameters of the veins and distances from the confluence to the IMV origins. RESULTS: The frequency of variants was: 1. 37.6%, 2. 28.8%; 3. 19.2%. The rare variants totaled 14.4%. The average vessel diameters measured in cm: PV 1.48; SV 1.02; SMV 1.2; IMV 0.5. The mean IMV entering distances were 1.66 cm in variant 1 and 0.75 cm in variant 3. CONCLUSION: The three common variants (1, 2 and 3) are the most relevant ones. 14.4% of patients had different anatomic variants. The variability of the mesenteric venous system was higher than previously published. Knowledge of rare variants is important to avoid complications in abdominal surgery.

MRI assessment of cardiac amyloidosis: experience of six cases with review of the current literature.

Cardiac MRI is known to be diagnostically valuable in cardiac amyloidosis. Several features are frequently found, including myocardial hypertrophy, diastolic dysfunction, a faster gadolinium blood wash out, pleural and pericardial effusions, and diffuse myocardial delayed enhancement. Cardiac MR facilitates the detection of cardiac amyloidosis and allows longitudinal assessment of myocardial function. This pictorial review focuses on cases with histologically proven systemic amyloidosis and cardiac involvement in order to illustrate typical findings.

[Cardiac MRI in addition to MR angiography: a longitudinal study in vascular risk patients]. / Kardiale MRT als ergänzung zur MR-angiografie: eine longitudinale studie bei vaskulären risikopatienten.

PURPOSE: The aim of the study was to assess the feasibility and additional diagnostic information of cardiac MRI as a supplement to state-of-the-art MR angiography (MRA) in the case of vascular risk patients. Therefore, the prevalence of delayed myocardial enhancement (DE) was determined in patients suffering from peripheral artery disease (PAD) and a clinical follow-up was evaluated after 2 years. MATERIALS AND METHOD: 87 consecutive patients (ages 66 +/- 10 years, 67 males) with symptomatic peripheral arterial occlusive disease (n = 68) or abdominal aortic aneurysm (n = 19) were examined using delayed cardiac enhancement (DE) within the clinical indication of MRA at a 1.5T system. A follow-up examination was carried out two years later (24 months +/- 4 months) with regards to cardiac events (cardiac death, myocardial infarction or acute coronary syndrome, heart insufficiency, coronary revascularization). RESULTS: In total, 40 / 87 patients had myocardial infarctions shown in MRI (46 %). In 25 patients (29 %), the myocardial infarction was already known, while in 15 patients (17 %) an occult progressing infarction was diagnosed (38 % of the myocardial infarcts). Follow-up data was able to be obtained after 2 years for 82 patients. 15 patients had a major cardiac event during the follow-up period, and 10 (67 %) of them already showed DE in the MRI. In the group with occult progressing infarctions, cardiac events occurred in 40 % (6 / 15 patients, cardiac death n = 1, ischemia n = 4, heart insufficiency n = 1, bypass n = 1), in patients with known infarction in 17 % (4 / 23 patients, cardiac death n = 1, ischemia n = 3, bypass n = 2) and in 11 % of patients without myocardial scars (5 / 44 patients, cardiac death n = 1, ischemia n = 2, heart insufficiency n = 2). CONCLUSION: Cardiac MRI in combination with MRA was feasible and showed a high prevalence of known and unexpected myocardial infarctions. This was of prognostic relevance in the follow-up 2 years later. Therefore, this enables important additional information regarding to the risk stratification and eventually targeted therapy in risk patients with PAD.

[MR stress perfusion for the detection of flow-limiting stenoses in symptomatic patients with known coronary artery disease and history of stent implantation]. / MR-Stressperfusion zur Vorhersage flusslimitierender Stenosen bei symptomatischen Patienten mit bekannter KHK nach Stentimplantation.

PURPOSE: The aim of the present study was to determine the correlation of myocardial perfusion MR imaging (MPMRI) and coronary angiography for the detection of flow-limiting stenosis in symptomatic patients with known coronary artery disease and a history of intervention. MATERIALS AND METHODS: MPMRI was performed in 51 symptomatic patients (44 male, 64.7 +/- 9.5 years) with known coronary artery disease and a history of stent implantation (between 5 years and 2 weeks prior to MRI). Malperfused myocardial regions were correlated with findings of coronary angiography. A stenosis of > 70% was regarded as hemodynamically significant. RESULTS: In MPMRI 37 patients (73%) showed a stress induced perfusion deficit. In 35 of these patients coronary angiography revealed a stenosis of > 70 %. A total of 38 patients (75%) showed stenoses of > 70%. MPMRI yielded a sensitivity of 92% with a specificity of 85 %. The positive predictive value was 95 % and negative predictive value was 79%. The assignment of malperfused segments to coronary artery territories was carried out according to the standardized myocardial model of the American Heart Association (sensitivity/specificity was 59/85% for RCA, 79/81% for LAD and 54/68 % for LCX). CONCLUSION: MPMRI is a suitable non-invasive method for detecting flow-limiting coronary artery stenoses in patients with a history of stent implantation.

Placement of the preparation line and periodontal health--a prospective 2-year clinical study.

The aim of this prospective clinical 2-year study was to determine whether the placement of the proximal margins of crowns within the zone of the biologic width results in periodontal alterations. In 41 patients, 116 prepared teeth as well as 82 unrestored, healthy contralateral teeth were examined. The following indices were determined before as well as 3, 6, 12, and 24 months after preparation: hygiene index, papillary bleeding index (PBI), and probing depth. After preparation, the distance between the restoration margins and the alveolar crest was measured with a modified periodontal probe on both proximal aspects of each tooth. These values were classified into 3 groups: I = < or = 1 mm between crown margin and alveolar crest, II = 1 to 2 mm, and III = > 2 mm. In addition, radiographs were taken directly after cementation of each restoration and after 12 and 24 months. The hygiene index did not significantly vary during the investigation, but PBI increased in all groups. The highest PBI increase was found in group I; in this group, the most significant increase was found between 3 and 6 months after preparation. The mean probing depth only increased in group I during the first 3 months after preparation on the mesial aspects. Only minor changes were found on the distal aspects of the teeth in group I and on all aspects in groups II and III. No alterations of the bone levels were diagnosed on the radiographs. These results indicate that the location of the restoration margins within the zone of the biologic width may impair the periodontal health of restored teeth.

A Review of the Magnetic Relaxation and Its Application to the Study of Atomic Defects in α-Iron and Its Diluted Alloys.

This review presents a comprehensive survey on intensive studies performed during the last decades on point defect reactions on α-iron (α-Fe) and its diluted alloys. Our intention is to give an actual account of the knowledge accumulated on this subject, as it has been obtained predominantly by means of the magnetic after-effect (MAE) spectroscopy. After a concise introduction into the theoretical and experimental fundamentals of this technique, the main concern is focused on the presentation and detailed discussion of the MAE spectra arising - after low-temperature electron (e-)- or neutron(n)-irradiation and subsequent annealing - in: (i) high-purity α-Fe and α-Fe doped with (ii) substitutional solutes (like Ni, V, Al, Cu, Ti, Be, Si, Mn, …) or (iii) interstitial solutes (like O, H, C, N). During the course of systematic annealing treatments, these respective spectra undergo dramatic variations at specific temperatures thereby revealing in great detail the underlying intrinsic reactions of the radiation-induced defects, i.e., reorientation, migration, clustering, dissolution and finally annihilation. In alloyed Fe systems the corresponding reaction sequences are even multiplied due to additional interactions between defects and solute atoms. Most valuable information concerning formation-, dissociation- and binding enthalpies of small, mixed clusters (of the type C i V k , N i V k ; i, k ≥ 1) has been obtained in high-purity α-Fe base material which, after charging with C or N, had been e--irradiated. Concerning the basic recovery mechanisms in α-Fe, two complementary results are obtained from the analysis of the various systems: (i) in high-purity and substitutionally alloyed α-Fe the recovery in Stage-III (200 K) is governed by a three-dimensionally migrating (H M I = 0.56 eV) stable interstitial (dumb-bell); (ii) following the formation and dissociation kinetics of small clusters (C1V k , N1V k ) in interstitially alloyed α-Fe the migration enthalpy of the monovacancy must hold the following relation H M N (0.76 eV) < H M C (0.84 eV) < H M V1. These results are in clear agreement with the so-called two-interstitial model (2IM) in α-Fe - a conclusion being further substantiated by a systematic comparison with the results obtained from nonrelaxational techniques, like i.e. positron annihilation (PA), which by their authors are preferentially interpreted in terms of the one-interstitial model (1IM).

Two-step chromatographic procedure for purification of basic fibroblast growth factor from recombinant Escherichia coli and characterization of the equilibrium parameters of adsorption.

A two-step chromatographic procedure for purification of basic fibroblast growth factor (bFGF) from high-cell-density cultures of recombinant E. coli is described. Heparin-Sepharose as a material which shows a high affinity to endothelial growth factors was used as sorbent for purification of bFGF from the soluble cell fraction. A one-step affinity chromatographic procedure resulted in very pure bFGF. However, this one-step affinity isolation of bFGF caused the loss of around 60% of the recombinant protein. A combination of ion-exchange chromatography with heparin-Sepharose affinity chromatography was favored for bFGF purification. A first cation-exchange chromatographic step resulted in a solution of bFGF with a purity of around 70%. The weak cation exchanger CM Sepharose C50 was preferred in comparison to the strong cation exchanger S-Sepharose because of the higher recovery of bFGF. With the ion-exchange chromatographic step prior to the heparin-Sepharose affinity chromatography, the total yield of recovery of bFGF increased to 56% compared to 40% using the one-step purification procedure with heparin-Sepharose. To characterize the equilibrium parameters of adsorption, batch experiments for the calculation of maximum capacities and dissociation constants for CM-Sepharose C50 and heparin-Sepharose were carried out. The equilibrium experiments revealed that adsorption of bFGF to the ion-exchange sorbent followed single-site interaction according to the Langmuir model of adsorption. The adsorption of bFGF to heparin-Sepharose was described by a double Langmuir approach of two independent binding sites with different maximum capacities and dissociation constants. The purified bFGF showed a high biological activity and circular dichroic spectra of a proper folded molecule. The analysis of the N-terminal amino acid sequence revealed a mixture of two fractions of bFGF, which both are characterized by the cleavage of the first amino acid methionine. In addition, half of the bFGF molecules lacked the second amino acid alanine.