Multi-organ segmentation of the head and neck area: an efficient hierarchical neural networks approach

PURPOSE

In radiation therapy, a key step for a successful cancer treatment is image-based treatment planning. One objective of the planning phase is the fast and accurate segmentation of organs at risk and target structures from medical images. However, manual delineation of organs, which is still the gold standard in many clinical environments, is time-consuming and prone to inter-observer variations. Consequently, many automated segmentation methods have been developed.

METHODS

In this work, we train two hierarchical 3D neural networks to segment multiple organs at risk in the head and neck area. First, we train a coarse network on size-reduced medical images to locate the organs of interest. Second, a subsequent fine network on full-resolution images is trained for a final accurate segmentation. The proposed method is purely deep learning based; accordingly, no pre-registration or post-processing is required.

RESULTS

The approach has been applied on a publicly available computed tomography dataset, created for the MICCAI 2015 Auto-Segmentation challenge. In an extensive evaluation process, the best configurations for the trained networks have been determined. Compared to the existing methods, the presented approach shows state-of-the-art performance for the segmentation of seven different structures in the head and neck area.

CONCLUSION

We conclude that 3D neural networks outperform the most existing model- and atlas-based methods for the segmentation of organs at risk in the head and neck area. The ease of use, high accuracy and the test time efficiency of the method make it promising for image-based treatment planning in clinical practice.

[The risk of contracting hepatitis A or hepatitis B run by visitors to the Mediterranean and Eastern Europe]

Hepatitis A and B continue to represent a risk for travelers. Those traveling to tropical countries are usually aware of this risk, while those visiting a Mediterranean country often are not. This investigation presents a destination-related risk assessment and vaccination recommendations for travellers, on the basis of incidences and prevalences of hepatitis A and hepatitis B. For hepatitis B, the WHO classification based on HBsAg prevalence has been selected. For hepatitis A, countries have been categorized as low-, moderate- or high-risk. A comparison of infection risk with the numbers of airline passengers showed that in particular the large number of travelers to Tunisia, Turkey and Egypt, in conjunction with hygienic conditions in those countries, represent a source of imported hepatitis A. With regard to destinations in the Mediterranean and Eastern Europe, too, the risk of contracting hepatitis A or hepatitis B is not always negligible, so that vaccination may need to be recommended.

Sublingual specific immunotherapy for adults and children: a post-marketing surveillance study

BACKGROUND

Sublingual immunotherapy (SLIT) is a relatively new form of treatment for type I allergies and a good safety profile is rapidly being established. Evidence on the efficacy of SLIT is increasing, and the present study provides further supportive data. We describe the results of treatment with a SLIT vaccine formulated with a range of allergen extracts obtained by allergologists in daily clinical practice.

METHODS

Adult and child patients (n = 159, 81 males, 78 females) with confirmed type I allergic sensitivities were treated with a standardized SLIT vaccine (ORALVAC) using the sublingual-swallow method. Evaluation of the efficacy of SLIT was based on the consumption of anti-allergic medication and a global assessment. Tolerability assessment was based on the incidence of local or systemic reactions.

RESULTS

Medication use was significantly reduced compared with that in previous years (p = 0.023). In a large subgroup of patients treated for pollen sensitivity the significance was stronger (p = 0.016). Global assessment revealed that only 3.5 % of patients showed no change in symptoms after therapy. High tolerability was achieved and no serious or severe adverse effects were observed.

CONCLUSION

Over a one-year period, adult and child patients with a variety of type I allergies were treated with a SLIT vaccine that has shown significant efficacy and was well-tolerated with no serious or severe adverse events.

Single-course specific immunotherapy with mixed pollen allergoids: results of a multi-centre study

BACKGROUND

A short-term immunotherapy vaccine for the treatment of pollen allergy has been developed utilising L-tyrosine adsorbed allergoids. The reduced number of injections could provide advantages over long-term therapy schedules. This would improve compliance and support application of specific immunotherapy (SIT) to a greater extent. We report a multicenter study to evaluate the efficacy and safety of this treatment in a clinical practice setting.

METHODS

Patients (n = 1808) with a diagnosis of sensitivities to various pollens and symptoms of allergic asthma and/or allergic rhinitis and/or allergic conjunctivitis were selected. The vaccine formulation was made up according to individual sensitivities and contained L-tyrosine adsorbed allergoids. The patients were treated with a 3-injection initial course followed by a 3-injection maintenance course. Efficacy was measured by consumption of symptomatic anti-allergic medication compared with that in the previous season and by physician assessment using a 5-point scale. All adverse events were recorded.

RESULTS

Efficacy was demonstrated by a considerable decrease in regular and frequent use of medication compared with that in the previous season (p < 0.001). In addition, in 80 % of the patients, the physician's assessment was either "good" or "very good". These outcomes were unaffected by the closeness of the treatment course to the onset of the pollen season. Tolerability was good and most local and systemic reactions were mild.

CONCLUSIONS

The treatment of pollen-allergic patients with a short-term SIT using a 6-injection pollen allergoid/L-tyrosine vaccine in a clinical practice setting provided a high level of efficacy with a low incidence of mainly mild adverse events.

Human cutaneous leishmaniasis caused by Leishmania naiffi is wide-spread in South America

Four human cases of localized cutaneous leishmaniasis caused by Leishmania naiffi are reported. Two of the cases were infected in French Guiana, one in French Guiana or Martinique, and the other in Ecuador or Peru. The geographical distribution of L. naiffi is clearly larger than that initially reported. Three zymodemes were represented by the four isolates, confirming that there is intraspecific polymorphism in L. naiffi.

Influence of rheumatoid factor on the specificity of a rapid immunochromatographic test for diagnosing dengue infection

In order to determine the influence of rheumatoid factor in serum specimens on the specificity of an immunochromatographic test for the detection of antibodies against dengue virus, 50 clinical specimens containing rheumatoid factor were evaluated for cross reactivity with a commercially available assay. While specificity for the detection of immunoglobulin (Ig) G antibodies was 100%, the IgM component of the test showed false-positive results in 26% of cases. Thus, it is important to consider interference by rheumatoid factor when using immunochromatographic assays for the detection of specific IgM produced during dengue infection.

Population structure of recrudescent Plasmodium falciparum isolates from western Uganda

It has been proposed that polymorphisms of the Merozoite Surface Protein 1 and 2 (MSP1 and MSP2) and the Glutamate Rich Protein (GLURP) genes can be considered as genetic markers for the genotyping of field populations of Plasmodium falciparum. During a field study on in vivo drug resistance against chloroquine, sulphadoxine/pyrimethamine (S/P) and cotrimoxazole in West Uganda, sensitive and resistant isolates were collected from patients by fingerprick for genotyping. 59 (72.8%) of the 81 P. falciparum samples isolated at day 0 showed multiclonal infection with 2-7 clones. Among the isolates we investigated, presence of the allelic family MAD20 of MSP1 at day 0 was significantly (P = 0.0041) associated with decreased resistance to antimalarials. Use of this method in a field study on in vivo drug resistance demonstrates another potential application of genotyping as a tool for epidemiological investigations.

[Persistent arthralgias in Ross-River-Virus disease after travel to the South Pacific]

HISTORY AND CLINICAL FINDINGS

A 57-year-old patient presented with malaise and severe persistent arthralgia of the left shoulder. He reported an acute illness with fever, generalized myalgia and arthralgias of the large joints which had started one month earlier during his flight back to Germany after a two weeks trip to the South Pacific. Physical examination showed extensive pain on palpation of the glenohumeral and acromioclavicular joints with impairment of active and passive mobility. Investigation of the cervical spine was normal.

INVESTIGATIONS

Apart from elevated C-reactive protein and erythrocyte sedimentation rate levels, routine laboratory investigations were normal including negative immunodiagnostic tests for autoantibodies and various global infections that may be associated with arthritis. Immunofluorescence tests showed significant levels of specific IgM- and IgG-antibodies against Ross River virus (RRV) but not against other arboviruses endemic in the South Pacific and Australia (Dengue, West Nile, Chikungunya, Sindbis, Barmah Forest). This was confirmed by a positive RRV neutralisation test. Attempts at virus isolation and detection of viral RNA by PCR were not successful.

TREATMENT AND COURSE

Symptomatic treatment with high doses of diclofenac quickly led to pain relief, and arthralgias receded within 10 days after begin of treatment. However, several bouts of arthralgia of the left shoulder and left knee occurred during a period of 4 months.

CONCLUSIONS

Because of the current epidemiological situation in the South Pacific and Australia, infections by arboviruses like RRV should be considered in travellers returning from these areas with severe and persistent arthralgia of unknown origin, even in the absence of fever and other symptoms of acute infection.

Plasmodium falciparum and Plasmodium berghei: effect of magnesium on the development of parasitemia

The in vitro growth of Plasmodium falciparum was reduced by 35 and 43% through high concentrations (5 mmole/liter) of magnesium in RPMI medium and magnesium-free medium, respectively, after 48 hr, whereas no significant inhibition could be observed under these conditions after 24 hr cultivation in the respective medium. Levels of magnesium between 0.5 and 3 mmole/liter showed no inhibitory effect on the in vitro growth of P. falciparum even after long-term exposure for 7 days. The 50 and 90% chloroquine inhibitory concentrations of the chloroquine-resistant strain K1 after 24 hr were reduced to some extent in the presence of magnesium at 5 mmole/liter, but less than in the presence of verapamil at 10 mumole/liter, which showed intrinsic activities at this concentration and which completely reversed resistance. However, high physiologic magnesium plasma levels were associated with a significantly longer survival time of NMRI mice infected with P. berghei strain ANKA, compared to normal physiological plasma magnesium levels. It is concluded that in the case of clinically symptomatic magnesium deficiency, supplementation of magnesium will not aggravate concomitant plasmodial infections and therefore should not be withheld.

[Chronic subdural hematoma in aged patients. Diagnostic problems]

The history, clinical features, laboratory tests and admission circumstances were analysed retrospectively in 14 patients, aged 60 to 87 years, who were found to have a chronic subdural haematoma. Typical clinical features consisted of dominant psychiatric disorders, slow progression and frequently only traces of neurological signs. In only four patients was headache the initial symptom. Delay in diagnosis and treatment worsened the prognosis. Several factors account for the nonspecific signs and symptoms: diffuse cerebral atrophy, dementia of a degenerative or vascular nature, and cerebral decompensation. Computed tomography immediately after a trauma may be negative.