Next Issue
Volume 3, March
Previous Issue
Volume 2, September
 
 

Diagnostics, Volume 2, Issue 4 (December 2012) – 6 articles , Pages 42-106

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:

Research

Jump to: Review

471 KiB  
Article
Importance of Attenuation Correction (AC) for Small Animal PET Imaging
by Henrik H. El Ali, Rasmus Poul Bodholdt, Jesper Tranekjær Jørgensen, Rebecca Myschetzky and Andreas Kjaer
Diagnostics 2012, 2(4), 42-51; https://doi.org/10.3390/diagnostics2040042 - 09 Oct 2012
Cited by 49 | Viewed by 9938
Abstract
The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. [...] Read more.
The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%), for kidneys 20 ± 1% (19–21%), and for bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction. Full article
(This article belongs to the Collection Feature Papers)
Show Figures

Figure 1

139 KiB  
Communication
Visual Suppression is Impaired in Spinocerebellar Ataxia Type 6 but Preserved in Benign Paroxysmal Positional Vertigo
by Masahiko Kishi, Ryuji Sakakibara, Tomoe Yoshida, Masahiko Yamamoto, Mitsuya Suzuki, Manabu Kataoka, Yohei Tsuyusaki, Akihiko Tateno and Fuyuki Tateno
Diagnostics 2012, 2(4), 52-56; https://doi.org/10.3390/diagnostics2040052 - 11 Oct 2012
Cited by 45 | Viewed by 5497
Abstract
Positional vertigo is a common neurologic emergency and mostly the etiology is peripheral. However, central diseases may mimic peripheral positional vertigo at their initial presentation. We here describe the results of a visual suppression test in six patients with spinocerebellar ataxia type 6 [...] Read more.
Positional vertigo is a common neurologic emergency and mostly the etiology is peripheral. However, central diseases may mimic peripheral positional vertigo at their initial presentation. We here describe the results of a visual suppression test in six patients with spinocerebellar ataxia type 6 (SCA6), a central positional vertigo, and nine patients with benign paroxysmal positional vertigo (BPPV), the major peripheral positional vertigo. As a result, the visual suppression value of both diseases differed significantly; e.g., 22.5% in SCA6 and 64.3% in BPPV (p < 0.001). There was a positive correlation between the visual suppression value and disease duration, cerebellar atrophy, and CAG repeat length of SCA6 but they were not statistically significant. In conclusion, the present study showed for the first time that visual suppression is impaired in SCA6, a central positional vertigo, but preserved in BPPV, the major peripheral positional vertigo, by directly comparing both groups. The abnormality in the SCA6 group presumably reflects dysfunction in the central visual fixation pathway at the cerebellar flocculus and nodulus. This simple test might aid differential diagnosis of peripheral and central positional vertigo at the earlier stage of disease. Full article
Show Figures

Figure 1

997 KiB  
Article
Prenatal Diagnosis of Chromosome Abnormalities: A 13-Year Institution Experience
by Carmen Comas, Mónica Echevarria, María Ángeles Rodríguez, Ignacio Rodríguez, Bernat Serra and Vincenzo Cirigliano
Diagnostics 2012, 2(4), 57-71; https://doi.org/10.3390/diagnostics2040057 - 19 Nov 2012
Cited by 40 | Viewed by 8824
Abstract
Objective: To analyze trends in screening and invasive prenatal diagnosis of chromosome abnormalities (CA) over a 13-year period and correlate them to changes in the national prenatal screening policy. Methods: We retrospectively reviewed Down syndrome (DS) screening tests and fetal karyotypes [...] Read more.
Objective: To analyze trends in screening and invasive prenatal diagnosis of chromosome abnormalities (CA) over a 13-year period and correlate them to changes in the national prenatal screening policy. Methods: We retrospectively reviewed Down syndrome (DS) screening tests and fetal karyotypes obtained by prenatal invasive testing (IT) in our fetal medicine unit between January 1999 and December 2011. Results: A total of 24,226 prenatal screening tests for DS and 11,045 invasive procedures have been analyzed. Over a 13-year period, utilization of non-invasive screening methods has significantly increased from 57% to 89%. The percentage of invasive procedures has declined from 49% to 12%, although the percentage of IT performed for maternal anxiety has increased from 22% to 55%. The percentage of detected CA increased from 2.5% to 5.9%. Overall, 31 invasive procedures are needed to diagnose 1 abnormal case, being 23 procedures in medical indications and 241 procedures in non-medical indications. Conclusions: Our experience on screening and invasive prenatal diagnostic practice shows a decrease of the number of IT, with a parallel decline in medical indications. There is an increasing efficiency of prenatal screening program to detect CA. Despite the increasing screening policies, our population shows a growing request for prenatal IT. The a priori low risk population shows a not negligible residual risk for relevant CA. This observation challenges the current prenatal screening strategy focused on DS; showing that the residual risk is higher than the current cut-off used to indicate an invasive technique. Full article
(This article belongs to the Special Issue Advance in Prenatal Diagnosis)
Show Figures

Graphical abstract

716 KiB  
Article
Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA
by Cuong Cao, Sam W. Birtwell, Jonas Høgberg, Hywel Morgan, Anders Wolff and Dang Duong Bang
Diagnostics 2012, 2(4), 72-82; https://doi.org/10.3390/diagnostics2040072 - 29 Nov 2012
Cited by 14 | Viewed by 9659
Abstract
SU-8 epoxy-based negative photoresist has been extensively employed as a structural material for fabrication of numerous biological microelectro-mechanical systems (Bio-MEMS) or lab-on-a-chip (LOC) devices. However, SU-8 has a high autofluorescence level that limits sensitivity of microdevices that use fluorescence as the predominant detection [...] Read more.
SU-8 epoxy-based negative photoresist has been extensively employed as a structural material for fabrication of numerous biological microelectro-mechanical systems (Bio-MEMS) or lab-on-a-chip (LOC) devices. However, SU-8 has a high autofluorescence level that limits sensitivity of microdevices that use fluorescence as the predominant detection workhorse. Here, we show that deposition of a thin gold nanoparticles layer onto the SU-8 surface significantly reduces the autofluorescence of the coated SU-8 surface by as much as 81% compared to bare SU-8. Furthermore, DNA probes can easily be immobilized on the Au surface with high thermal stability. These improvements enabled sensitive DNA detection by simple DNA hybridization down to 1 nM (a two orders of magnitude improvement) or by solid-phase PCR with sub-picomolar sensitivity. The approach is simple and easy to perform, making it suitable for various Bio-MEMs and LOC devices that use SU-8 as a structural material. Full article
(This article belongs to the Special Issue Microfluidic Lab-on-a-Chip Platforms for High-Performance Diagnostics)
Show Figures

Graphical abstract

10122 KiB  
Article
Detection of Dissolved Lactose Employing an Optofluidic Micro-System
by Emanuel Weber, Franz Keplinger and Michael J. Vellekoop
Diagnostics 2012, 2(4), 97-106; https://doi.org/10.3390/diagnostics2040097 - 06 Dec 2012
Cited by 305 | Viewed by 7111
Abstract
In this work, a novel optofluidic sensor principle is employed for a non-invasive and label-free characterization of lactose containing liquid samples. Especially for medicine and food industry, a simple, fast and accurate determination of the amount of lactose in various products is highly [...] Read more.
In this work, a novel optofluidic sensor principle is employed for a non-invasive and label-free characterization of lactose containing liquid samples. Especially for medicine and food industry, a simple, fast and accurate determination of the amount of lactose in various products is highly desirable. The presented system exploits the impact of dissolved molecules on the refractive index for sample characterization. On the optofluidic chip, a microfluidic channel filled with the analyte is hit by slightly diverging laser light. The center incident angle of the beam on-chip is set close to the critical angle for total internal reflection. Both the reflected and the transmitted light signals are recorded at the solid-liquid interface. The ratio of those two signals is then used as representative value for the analyte. Using this principle, lactose containing samples were differentiated based on their concentrations at a step size of 10 mmol/L. The use of the signals ratio instead of a single signal approach improves the stability of the system significantly, allowing for higher resolutions to be achieved. Furthermore, the fabrication of the devices in PDMS ensures biocompatibility and provides low absorbance of light in the visible range. Full article
(This article belongs to the Special Issue Microfluidic Lab-on-a-Chip Platforms for High-Performance Diagnostics)
Show Figures

Graphical abstract

Review

Jump to: Research

825 KiB  
Review
Cell-Based Biosensors: Electrical Sensing in Microfluidic Devices
by Katrine Kiilerich-Pedersen and Noemi Rozlosnik
Diagnostics 2012, 2(4), 83-96; https://doi.org/10.3390/diagnostics2040083 - 06 Dec 2012
Cited by 33 | Viewed by 10008
Abstract
Cell-based biosensors provide new horizons for medical diagnostics by adopting complex recognition elements such as mammalian cells in microfluidic devices that are simple, cost efficient and disposable. This combination renders possible a new range of applications in the fields of diagnostics and personalized [...] Read more.
Cell-based biosensors provide new horizons for medical diagnostics by adopting complex recognition elements such as mammalian cells in microfluidic devices that are simple, cost efficient and disposable. This combination renders possible a new range of applications in the fields of diagnostics and personalized medicine. The review looks at the most recent developments in cell-based biosensing microfluidic systems with electrical and electrochemical transduction, and relevance to medical diagnostics. Full article
(This article belongs to the Special Issue Microfluidic Lab-on-a-Chip Platforms for High-Performance Diagnostics)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop