Validating incentive salience with functional magnetic resonance imaging: association between mesolimbic cue reactivity and attentional bias in alcohol-dependent patients

Alcohol-associated cues are able to elicit brain activations in mesocorticolimbic networks that are related to the rewarding properties of the drug. Some authors hypothesize that the activation of the mesocorticolimbic reward system triggers an attention allocation to alcohol-associated cues. Yet, no functional magnetic resonance imaging (fMRI) studies examining this proposition are available. In this fMRI study we investigate the association between attentional bias and neural cue reactivity. Thirty-eight recently abstinent alcohol-dependent patients were examined. fMRI was used to study cue reactivity during the presentation of alcohol-related pictures. A modified visual dot-probe task was used to assess attentional bias. Alcohol-dependent patients showed an attentional bias to alcohol-associated cues as well as cue-induced fMRI activation in response to alcohol-related stimuli in limbic and reward-related brain regions and visual areas. We found a positive correlation between cue-induced brain activation and attentional bias score in a network including frontal, temporal and subcortical regions. This study is the first demonstrating that, in line with previous suggestions, cue induced activation of the mesocorticolimbic reward system triggers focusing attention to substance-associated cues. However, this association could also be bidirectional with the attentional bias enhancing cue-induced neural activity.

[Diffusion-weighted MRI - how many B-values are necessary?]

PURPOSE

Diffusion-weighted imaging (DWI) has become an important component in modern stroke imaging. This MR technique detects diffusion abnormalities, which can be quantified by computing apparent diffusion coefficient (ADC) maps. ADC values are typically calculated from a set of MR images obtained with varying degrees of diffusion weighting (b-values) using nonlinear regression. However, there is no agreement concerning the number of images needed for ADC calculation. The aim of our study was to determine how many b-values are necessary to reliably calculate ADC maps.

MATERIALS AND METHODS

In 100 consecutive patients with clinical signs of acute ischemic stroke, 6 identically oriented and centered diffusion data sets with different b-values were acquired. ROI analysis was performed for DWI-positive lesions, normal-appearing gray and white matter, CSF, and background noise. ADC values for each ROI were calculated using a nonlinear regression model. Additionally, the CNR and SNR were calculated for each ROI.

RESULTS

Acquisition time was 0:39 min for 2 b-values and up to 2:49 min for a sequence with 7 b-values. The mean ADC (× 10(-3) mm2/s) for ischemic lesions was 58.29, 58.47, 57.83, 57.81, 57.58 and 54.51 using 2, 3, 4, 5, 6, and 7 b-values. Ischemic lesions had significantly different mean ADC values only for high b-values (b = 2000 s/mm2).

CONCLUSION

ADC values can be reliably calculated using 2 b-values. Radiologists may use the more time-efficient 2-point method for reliably estimating ADC values and detecting ischemic lesions in the daily clinical routine.

[Diagnosing neurovascular compression syndromes]

PURPOSE

Neurovascular compression syndromes are diseases caused by abnormal contact between a vessel loop and the root exit/entry zone of a cranial nerve. Compression can cause paroxysmal attacks of abnormal motor or sensory phenomena in the affected nerve.

MATERIALS AND METHODS

Review based on a selective analysis of the literature.

RESULTS

Neurovascular compression syndromes include well-established entities such as trigeminal neuralgia, facial hemispasm, vestibular paroxysmia and glossopharyngeus neuralgia but also cranial nerve disorders caused by compression due to an aneurysm, e. g., oculomotor nerve paresis caused by an aneurysm of the posterior communicating branch. An overview of neurovascular compression syndromes is given, outlining diagnostic procedures and the morphological imaging features of each syndrome as well as the changes seen after treatment are described.

CONCLUSION

Neurovascular compression syndromes are complex diseases. MR imaging plays an important role in the diagnostic workup of these diseases.

Long-term follow-up of high-dose chemotherapy with autologous stem-cell transplantation and response-adapted whole-brain radiotherapy for newly diagnosed primary CNS lymphoma: results of the multicenter Ostdeutsche Studiengruppe Hamatologie und Onkologie OSHO-53 phase II study

BACKGROUND

We previously reported the results of a phase II study for patients with newly diagnosed primary central nervous system lymphoma treated with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiotherapy (WBRT). Now, we update the initial results.

PATIENTS AND METHODS

From 1999 to 2004, 23 patients received high-dose methotrexate. In case of at least partial remission, high-dose busulfan/thiotepa (HD-BuTT) followed by aPBSCT was carried out. Patients refractory to induction or without complete remission after HD-BuTT received WBRT. Eight patients still alive in 2011 were contacted and Mini-Mental State Examination (MMSE) and the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire (QLQ)-C30 were carried out.

RESULTS

Of eight patients still alive, median follow-up is 116.9 months. Only one of nine irradiated patients is still alive with a severe neurologic deficit. In seven of eight patients treated with HD-BuTT, health condition and quality of life are excellent. MMSE and QLQ-C30 showed remarkably good results in patients who did not receive WBRT. All of them have a Karnofsky score of 90%-100%.

CONCLUSIONS

Follow-up shows an overall survival of 35%. In six of seven patients where WBRT could be avoided, no long-term neurotoxicity has been observed and all patients have an excellent quality of life.

The necessity for the coating of perfluorodecalin-filled poly(lactide-co-glycolide) microcapsules in the presence of physiological cholate concentrations: Tetronic-908 as an exemplary polymeric surfactant

Recently, we demonstrated that biodegradable poly(lactide-co-glycolide) (PLGA) micro- and nanocapsules with a liquid content of perfluorodecalin are principally useful for the development of artificial oxygen carriers. In order to solve a decisive and well-known problem with PLGA microcapsules, i.e. the spontaneous agglomeration of the capsules after depletion of the emulsifying agent (i.e. cholate), coating with the ABA block copolymer, Tetronic-908 was studied. After Tetronic-908 treatment at concentrations that were harmless to cultured cells, the clustering of the microcapsules was prevented, the adsorption of opsonins was decreased and the attachment to cells was inhibited, but the oxygen transport capacity of PLGA microcapsules was even increased. The present data clearly show that perfluorodecalin-filled PLGA microcapsules must be coated before decreasing the emulsifying agent cholate to physiological concentrations, in order to develop a solution that has the capabilities to function as a potential artificial oxygen carrier suspension.

Effects of cue-exposure treatment on neural cue reactivity in alcohol dependence: a randomized trial

BACKGROUND

In alcohol-dependent patients, alcohol-associated cues elicit brain activation in mesocorticolimbic networks involved in relapse mechanisms. Cue-exposure based extinction training (CET) has been shown to be efficacious in the treatment of alcoholism; however, it has remained unexplored whether CET mediates its therapeutic effects via changes of activity in mesolimbic networks in response to alcohol cues. In this study, we assessed CET treatment effects on cue-induced responses using functional magnetic resonance imaging (fMRI).

METHODS

In a randomized controlled trial, abstinent alcohol-dependent patients were randomly assigned to a CET group (n = 15) or a control group (n = 15). All patients underwent an extended detoxification treatment comprising medically supervised detoxification, health education, and supportive therapy. The CET patients additionally received nine CET sessions over 3 weeks, exposing the patient to his/her preferred alcoholic beverage. Cue-induced fMRI activation to alcohol cues was measured at pretreatment and posttreatment.

RESULTS

Compared with pretreatment, fMRI cue-reactivity reduction was greater in the CET relative to the control group, especially in the anterior cingulate gyrus and the insula, as well as limbic and frontal regions. Before treatment, increased cue-induced fMRI activation was found in limbic and reward-related brain regions and in visual areas. After treatment, the CET group showed less activation than the control group in the left ventral striatum.

CONCLUSIONS

The study provides first evidence that an exposure-based psychotherapeutic intervention in the treatment of alcoholism impacts on brain areas relevant for addiction memory and attentional focus to alcohol-associated cues and affects mesocorticolimbic reward pathways suggested to be pathophysiologically involved in addiction.

Percutaneous balloon kyphoplasty with the patient under intravenous analgesia and sedation: a feasibility study

BACKGROUND AND PURPOSE

Kyphoplasty is a minimally invasive procedure for the treatment of malignant or osteoporotic vertebral compression fractures, normally performed with the patient under general anesthesia. This may cause a therapeutic dilemma because these patients often have a very high risk for general anesthesia due to concomitant diseases. The aim of this study was to evaluate the safety and feasibility of percutaneous kyphoplasty by using IV anesthesia and sedation with midazolam and piritramide.

MATERIALS AND METHODS

From June 2007 to June 2009, we prospectively included 133 patients (77 women, 56 men; mean age, 69.18 ± 11.45 years) who were referred for BKP. Kyphoplasty was always performed under fluoroscopic guidance with a biplane angiographic system by using a transpedicular or extrapedicular approach. The individual anesthesia risk was assessed by using the ASA criteria. All procedures were performed with the patient under IV anesthesia and sedation with fractionated administration of midazolam and piritramide. Pain was assessed before and after treatment by using a VAS.

RESULTS

Ninety-nine patients (74.4%) had a significantly increased risk for general anesthesia (ASA score, ≥ 3). A total of 162 kyphoplasty procedures were performed. The mean amounts of midazolam and piritramide used were 11.3 ± 4.38 mg and 11.8 ± 3.98 mg, respectively. No complications related to IV anesthesia and sedation occurred. Periprocedural pain management was rated as sufficient, and all patients would undergo the procedure again.

CONCLUSIONS

Percutaneous BKP with the patient under IV anesthesia and sedation with midazolam and piritramide is a safe and feasible method for treating vertebral compression fractures in patients with an increased risk for general anesthesia.