DicomWorks: software for reviewing DICOM studies and promoting low-cost teleradiology

Artificial Intelligence in Pancreatic Image Analysis: A Review

Pancreatic cancer is a highly lethal disease with a poor prognosis. Its early diagnosis and accurate treatment mainly rely on medical imaging, so accurate medical image analysis is especially vital for pancreatic cancer patients. However, medical image analysis of pancreatic cancer is facing challenges due to ambiguous symptoms, high misdiagnosis rates, and significant financial costs. Artificial intelligence (AI) offers a promising solution by relieving medical personnel's workload, improving clinical decision-making, and reducing patient costs. This study focuses on AI applications such as segmentation, classification, object detection, and prognosis prediction across five types of medical imaging: CT, MRI, EUS, PET, and pathological images, as well as integrating these imaging modalities to boost diagnostic accuracy and treatment efficiency. In addition, this study discusses current hot topics and future directions aimed at overcoming the challenges in AI-enabled automated pancreatic cancer diagnosis algorithms.

Sirenomelia: An anatomical assessment and genetic sex determination of two cases

The etiology of sirenomelia is currently unknown. Data are limited in comparing external and internal abnormalities using modern imaging technologies and molecular genetic analysis. The purpose of the current study was designed to compare external and internal anatomical defects in two cases of sirenomelia and Potter's sequence. Considered rare, Potter's sequence is a fetal disorder with characteristic features of bilateral renal agenesis, obstructive uropathy, atypical facial appearance, and limb malformations. The internal and external malformations of two term fetuses with sirenomelia and Potter's sequence were compared using assessment of external features, radiography and MRI on internal structures, and molecular genetic studies on sex determination. Data reveal that both fetuses were male and manifested with an overlapping but distinct spectrum of abnormalities. Principal differences were noted in the development of the ears, brain, urogenital system, lower limbs, pelvis, and vertebral column. Defects of the axial mesoderm are likely to underlie the abnormalities seen in both fetuses. The first one, which had only caudal defects, was found to have a spectrum of abnormalities most similar to those associated with more severe forms of the small pelvic outlet syndrome, although the structure and orientation of the sacrum and iliae were different from previously reported cases. The other had both caudal and cranial defects, and was most similar to those described in the axial mesodermal dysplasia syndrome. Defects associated with sirenomelia can be evaluated with standard gross anatomy examination, radiology, MRI, and modified PCR techniques to determine anatomical abnormalities and the sex of preserved specimens, respectively. Evidence indicated that sirenomelia could be developed via various etiologies.

Free DICOM-Viewers for Veterinary Medicine : Survey and Comparison of Functionality and User-Friendliness of Medical Imaging PACS-DICOM-Viewer Freeware for Specific Use in Veterinary Medicine Practices

There is increasing prevalence of digital diagnostic imaging in veterinary medicine with a progressive need to use medical imaging software. As Digital Imaging and Communications in Medicine (DICOM)-viewers for veterinary use do not require medical device approval in many countries, freeware viewers might be a practical alternative. The aim of this study was to identify and evaluate free DICOM-viewer software for veterinary purposes. The functionality and user-friendliness of various DICOM-viewers from the internet were analyzed and compared. Inclusion criteria for the evaluation were free availability, PACS (picture archiving and communication system)-connectivity, and stand-alone and client-based software. Based on this, eight viewers were found: Ginkgo CADx, Horos, K-PACS, MAYAM, MITO, OsiriX Lite, RadiAnt, Synedra personal. In these DICOM-viewers, 14 core tools were tested and rated on a score from 1 to 10 by multiple observers with different levels of training, using studies of four imaging modalities. Criteria were functionality and user-friendliness. For each viewer, the total number of a predefined set of 47 important tools was counted. The ranking based on functionality and user-friendliness of 14 core tools (mean score in brackets) was as follows: 1. Horos/OsiriX Lite (8.96), 2. RadiAnt (8.90), 3. K-PACS (8.02), 4. Synedra (7.43), 5. MAYAM (6.05), 6. Ginkgo CADx (5.53), 7. MITO (3.74). The DICOM-viewers offered between 20 and 44 tools of the predefined important tool set and are sufficient for most veterinary purposes. An increasing number of tools did not necessarily impair user-friendliness, if the user interface is well designed. Based on the results of this study, veterinarians will find suitable free DICOM-viewers for their individual needs. In combination with PACS-freeware, this allows veterinary practices to run a low-budget digital imaging environment.

Mechanical Ventilation Strategy Guided by Transpulmonary Pressure in Severe Acute Respiratory Distress Syndrome Treated With Venovenous Extracorporeal Membrane Oxygenation

OBJECTIVES

Previous studies have suggested that adjusting ventilator settings based on transpulmonary pressure measurements may minimize ventilator-induced lung injury, but this has never been investigated in patients with severe acute respiratory distress syndrome supported with venovenous extracorporeal membrane oxygenation. We aimed to evaluate whether a transpulmonary pressure-guided ventilation strategy would increase the proportion of patients successfully weaned from venovenous extracorporeal membrane oxygenation support in patients with severe acute respiratory distress syndrome.

DESIGN

Single-center, prospective, randomized controlled trial.

SETTING

Sixteen-bed, respiratory ICU at a tertiary academic medical center.

PATIENTS

Severe acute respiratory distress syndrome patients receiving venovenous extracorporeal membrane oxygenation.

INTERVENTIONS

One-hundred four patients were randomized to transpulmonary pressure-guided ventilation group (n = 52) or lung rest strategy group (n = 52) groups. Two patients had cardiac arrest during establishment of venovenous extracorporeal membrane oxygenation in the lung rest group did not receive the assigned intervention. Thus, 102 patients were included in the analysis.

MEASUREMENTS AND MAIN RESULTS

The proportion of patients successfully weaned from venovenous extracorporeal membrane oxygenation in the transpulmonary pressure-guided group was significantly higher than that in the lung rest group (71.2% vs 48.0%; p = 0.017). Compared with the lung rest group, driving pressure, tidal volumes, and mechanical power were significantly lower, and positive end-expiratory pressure was significantly higher, in the transpulmonary pressure-guided group during venovenous extracorporeal membrane oxygenation support. In the transpulmonary pressure-guided group, levels of interleukin-1β, interleukin-6, and interleukin-8 were significantly lower, and interleukin-10 was significantly higher, than those of the lung rest group over time. Lung density was significantly lower in the transpulmonary pressure-guided group after venovenous extracorporeal membrane oxygenation support than in the lung rest group.

CONCLUSIONS

A transpulmonary pressure-guided ventilation strategy could increase the proportion of patients with severe acute respiratory distress syndrome successfully weaned from venovenous extracorporeal membrane oxygenation.

Glucosamine Conjugated Gadolinium (III) Oxide Nanoparticles as a Novel Targeted Contrast Agent for Cancer Diagnosis in MRI

BACKGROUND

Glucose transporter (Glut), a cellular transmembrane receptor, has a key role in the metabolism of cell glucose and is also associated with various human carcinomas.

OBJECTIVE

In this study, we evaluated a magnetic resonance (MR) imaging contrast agent for tumor detection based on paramagnetic gadolinium oxide (Gd₂O₃) coated polycyclodextrin (PCD) and modified with glucose (Gd₂O₃@PCD-Glu) for the targeting of overexpressed glucose receptors.

MATERIAL AND METHODS

In this experimental study, 3T magnetic resonance imaging (MRI) scanner was used to assess the specific interactions between Glut1-overexpressing tumor cells (MDA-MB-231) and Gd₂O₃@PCD-Glu NPs. Furthermore, the capacity of transporting Gd₂O₃@PCD-Glu NPs to tumor cells was evaluated.

RESULTS

It was found that the acquired MRI T₁ signal intensity of MDA-MB-231 cells that were treated with the Gd₂O₃@PCD-Glu NPs increased significantly. Based on the results obtained, Gd₂O₃@PCD-Glu NPs can be applied in targeting Glut1-overexpressing tumor cells in vivo, as well as an MRI-targeted tumor agent to enhance tumor diagnosis.

CONCLUSION

Results have shown that glucose-shell of magnetic nanoparticles has a key role in diagnosing cancer cells of high metabolic activity.

DICOM Standard Conformance in Veterinary Medicine in Germany: a Survey of Imaging Studies in Referral Cases

In 2016, the recommendations of the DICOM Standards Committee for the use of veterinary identification DICOM tags had its 10th anniversary. The goal of our study was to survey veterinary DICOM standard conformance in Germany regarding the specific identification tags veterinarians should use in veterinary diagnostic imaging. We hypothesized that most veterinarians in Germany do not follow the guidelines of the DICOM Standards Committee. We analyzed the metadata of 488 imaging studies of referral cases from 115 different veterinary institutions in Germany by computer-aided DICOM header readout. We found that 25 (5.1%) of the imaging studies fully complied with the "veterinary DICOM standard" in this survey. The results confirmed our hypothesis that the recommendations of the DICOM Standards Committee for the consistent and advantageous use of veterinary identification tags have found minimal acceptance amongst German veterinarians. DICOM does not only enable connectivity between machines, DICOM also improves communication between veterinarians by sharing correct and valuable metadata for better patient care. Therefore, we recommend that lecturers, universities, societies, authorities, vendors, and other stakeholders should increase their effort to improve the spread of the veterinary DICOM standard in the veterinary world.

Pattern recognition for cache management in distributed medical imaging environments

PURPOSE

Traditionally, medical imaging repositories have been supported by indoor infrastructures with huge operational costs. This paradigm is changing thanks to cloud outsourcing which not only brings technological advantages but also facilitates inter-institutional workflows. However, communication latency is one main problem in this kind of approaches, since we are dealing with tremendous volumes of data. To minimize the impact of this issue, cache and prefetching are commonly used. The effectiveness of these mechanisms is highly dependent on their capability of accurately selecting the objects that will be needed soon.

METHODS

This paper describes a pattern recognition system based on artificial neural networks with incremental learning to evaluate, from a set of usage pattern, which one fits the user behavior at a given time. The accuracy of the pattern recognition model in distinct training conditions was also evaluated.

RESULTS

The solution was tested with a real-world dataset and a synthesized dataset, showing that incremental learning is advantageous. Even with very immature initial models, trained with just 1 week of data samples, the overall accuracy was very similar to the value obtained when using 75% of the long-term data for training the models. Preliminary results demonstrate an effective reduction in communication latency when using the proposed solution to feed a prefetching mechanism.

CONCLUSIONS

The proposed approach is very interesting for cache replacement and prefetching policies due to the good results obtained since the first deployment moments.

Free DICOM de-identification tools in clinical research: functioning and safety of patient privacy

Purpose

To compare non-commercial DICOM toolkits for their de-identification ability in removing a patient's personal health information (PHI) from a DICOM header.

Materials and Methods

Ten DICOM toolkits were selected for de-identification tests. Tests were performed by using the system’s default de-identification profile and, subsequently, the tools' best adjusted settings. We aimed to eliminate fifty elements considered to contain identifying patient information. The tools were also examined for their respective methods of customization.

Results

Only one tool was able to de-identify all required elements with the default setting. Not all of the toolkits provide a customizable de-identification profile. Six tools allowed changes by selecting the provided profiles, giving input through a graphical user interface (GUI) or configuration text file, or providing the appropriate command-line arguments. Using adjusted settings, four of those six toolkits were able to perform full de-identification.

Conclusion

Only five tools could properly de-identify the defined DICOM elements, and in four cases, only after careful customization. Therefore, free DICOM toolkits should be used with extreme care to prevent the risk of disclosing PHI, especially when using the default configuration. In case optimal security is required, one of the five toolkits is proposed.

Key Points

• Free DICOM toolkits should be carefully used to prevent patient identity disclosure.

• Each DICOM tool produces its own specific outcomes from the de-identification process.

• In case optimal security is required, using one DICOM toolkit is proposed.

Magnetic resonance arthrography assessment of the superior labrum using the BLC system: age-related changes mimicking SLAP-2 lesions

OBJECTIVE

The purpose of the study was to describe the variation of the superior labrum with increasing age by assessing magnetic resonance (MR) arthrograms.

METHODS

Inclusion criteria were used to include only the MR arthrograms of patients devoid of clinical labral pathology. Two hundred thiry-six MR arthrograms were blindly assessed for biceps-labral complex (BLC) type 1-3 and sublabral recess size by a musculoskeletal radiologist. We have chosen the BLC system, which defines normal superior labral variants, since it is established in the literature and is used by reporting musculoskeletal (MSK) radiologists.

RESULTS

The MR arthrograms demonstrated that the majority of patients <40 years old were BLC type 1 and showed a steady increase in BLC types 2 and 3 with increasing age. Assessments demonstrated significantly greater (p < 0.01) mean BLC types (1.62 vs 1.29) and recess size (1.35 vs 0.66 mm) in those over 40 compared with those less than 40 years of age. Furthermore, significant differences (p < 0.05) were noted between mean BLC assessments between different decades of age.

CONCLUSIONS

There appears to be a physiologic deepening of the superior labrum sulcus with age, which becomes significant after the age of 40. These findings can contribute to whether the superior labrum is considered abnormal when assessed radiographically. The differentiation of normal age-related changes in the shoulder, from those of a type 2 SLAP tear can reduce the rates of unnecessary SLAP-2 repairs. This is the first reported series to use the BLC system; we believe it provides a common nomenclature to allow clear communication between specialists.

Conjugation of glucosamine with Gd3+-based nanoporous silica using a heterobifunctional ANB-NOS crosslinker for imaging of cancer cells

BACKGROUND

The aim of this study was to synthesize Gd(3+)-based silica nanoparticles that conjugate easily with glucosamine and to investigate their use as a nanoprobe for detection of human fibrosarcoma cells.

METHODS

Based on the structure of the 2-fluoro-2-deoxy-D-glucose molecule ((18)FDG), a new compound consisting of D-glucose (1.1 nm) was conjugated with a Gd(3+)-based mesoporous silica nanoparticle using an N-5-azido-2-nitrobenzoyloxy succinimide (ANB-NOS) crosslinker The contrast agent obtained was characterized using a variety of methods, including Fourier transform infrared spectroscopy, nitrogen physisorption, thermogravimetric analysis, scanning and transmission electron microscopy, and inductively coupled plasma atomic emission spectrometry (ICP-AES). In vitro studies included cell toxicity, apoptosis, tumor necrosis factor-alpha, and hexokinase assays, and in vivo tests consisted of evaluation of blood glucose levels using the contrast compound and tumor imaging. The cellular uptake study was validated using ICP-AES. Magnetic resonance relaxivity of the contrast agent was determined using a 1.5 Tesla scanner.

RESULTS

ANB-NOS was found to be the preferred linker for attaching glucosamine onto the surface of the mesoporous silica nanospheres. The r1 relaxivity for the nanoparticles was 17.70 mM(-1)s(-1) per Gd(3+) ion, which is 4.4 times larger than that for Magnevist® (r1 approximately 4 mM(-1)s(-1) per Gd(3+) ion). The compound showed suitable cellular uptake (75.6% ± 2.01%) without any appreciable cytotoxicity.

CONCLUSION

Our results suggest that covalently attaching glucosamine molecules to mesoporous silica nanoparticles enables effective targeted delivery of a contrast agent.

Modified Gadonanotubes as a promising novel MRI contrasting agent

Background and purpose of the study

Carbon nanotubes (CNTs) are emerging drug and imaging carrier systems which show significant versatility. One of the extraordinary characteristics of CNTs as Magnetic Resonance Imaging (MRI) contrasting agent is the extremely large proton relaxivities when loaded with gadolinium ion (Gd_n³⁺) clusters.

Methods

In this study equated Gd_n³⁺ clusters were loaded in the sidewall defects of oxidized multiwalled (MW) CNTs. The amount of loaded gadolinium ion into the MWCNTs was quantified by inductively coupled plasma (ICP) method. To improve water solubility and biocompatibility of the system, the complexes were functionalized using diamine-terminated oligomeric poly (ethylene glycol) via a thermal reaction method.

Results

Gd_n³⁺ loaded PEGylated oxidized CNTs (Gd_n³⁺@CNTs-PEG) is freely soluble in water and stable in phosphate buffer saline having particle size of about 200 nm. Transmission electron microscopy (TEM) images clearly showed formation of PEGylated CNTs. MRI analysis showed that the prepared solution represents 10% more signal intensity even in half concentration of Gd³⁺ in comparison with commerciality available contrasting agent Magnevist®. In addition hydrophilic layer of PEG at the surface of CNTs could prepare stealth nanoparticles to escape RES.

Conclusion

It was shown that Gd_n³⁺@CNTs-PEG was capable to accumulate in tumors through enhanced permeability and retention effect. Moreover this system has a potential for early detection of diseases or tumors at the initial stages.

Acute myocardial infarction: early CT aspects of myocardial microcirculation obstruction after percutaneous coronary intervention

OBJECTIVE

To evaluate the capabilities of delayed enhanced multidetector CT (DE-MDCT), performed immediately after percutaneous coronary intervention (PCI), in predicting myocardial microvascular obstruction (MVO) formation assessed by delayed enhanced MRI (DE-MRI).

METHODS

Thirty-two patients presenting with a primary acute myocardial infarction, successfully recanalised by PCI, underwent a DE-MDCT immediately after PCI and a DE-MRI within 1 week. The left ventricle was split into 64 subsegments, rated as "healthy", "infarcted" or "MVO" on DE-MRI. Their mean density was measured on DE-MDCT and calculated relative to the patient's mean healthy myocardium density. Hypoenhanced DE-MDCT subsegments, termed "CT early MVO", were also recorded. Sensitivity and specificity of DE-MDCT for MRI-assessed "MVO" subsegments detection was calculated for mean CT relative density (threshold determined from a ROC analysis), "CT early MVO" and both.

RESULTS

Mean CT relative density was higher in MRI-assessed "MVO" than in "infarcted" and "healthy" subsegments (1.82 ± 0.46, 1.43 ± 0.36 and 1.0 ± 0.13 respectively; P < 0.001) leading to a sensitivity and specificity of 94.3 % and 89.2 % for a cutoff of 1.36. Sensitivity and specificity were respectively 16.9 % and 99.8 % for "CT early MVO" and 95.3 % and 89.3 % when considering the two patterns.

CONCLUSION

DE-MDCT, performed immediately after PCI, allows for an accurate prediction of MVO formation.

KEY POINTS

• Myocardial microvascular obstruction (MVO) is an important prognostic sequel following myocardial infarction. • MVO can be accurately predicted by multidector CT (MDCT). • Both hypo- and hyperenhanced myocardial areas can be analysed by MDCT. • MDCT may become a useful prognostic tool for acute MI outcome.

Gd(3+)-DTPA-DG: novel nanosized dual anticancer and molecular imaging agent

Background:

Difficulties in the use, preparation, and cost of radioactively-labeled glycosylated compounds led to this research and development study of a new gadolinium-labeled glucose compound that does not have a radioactive half-life or difficulties in its synthesis and utilization.

Methods:

Based on the structure of the 2-fluoro-2-deoxy-D-glucose molecule (¹⁸FDG), a new compound consisting of D-glucose (1.1 nm) conjugated to a well-known chelator, diethylenetriamine penta-acetic acid (DTPA), was synthesized, labeled with Gd³⁺, and examined in vitro and in vivo.

Results:

This novel compound not only demonstrated excellent and less costly imaging capability, but also showed anticancer effects on treated cells. Our results demonstrated that the new Gd³⁺-DTPA-DG compound (GDD, with GDD conjugate aggregation of about 8 nm at 0.02 mg/mL concentration) significantly decreased HT1080 and HT29 tumor cell numbers. Application of GDD to cancer cells also increased levels of tumor necrosis factor alpha, but did not alter blood glucose levels. Interestingly, no toxicological findings were seen in normal human kidney cells.

Conclusion:

Dual application of GDD for both imaging and treatment of tumor cells could be remarkably advantageous in both the diagnosis and treatment of cancer.

Atherosclerotic plaque progression in carotid arteries: monitoring with high-spatial-resolution MR imaging--multicenter trial

PURPOSE

To estimate the annualized rate of progression of vessel-wall volume in the carotid arteries in 160 patients by using magnetic resonance (MR) imaging and to establish the fraction of studies that have acceptable image quality.

MATERIALS AND METHODS

The study procedures and consent forms were reviewed and approved by each site's institutional review board. All U.S. study sites conducted all phases of this study in compliance with HIPAA requirements. Written consent was obtained from each participant. One hundred sixty patients with greater than 50% narrowing of the diameter of the carotid artery were recruited at six centers for prospective imaging of the carotid arteries at baseline and 1 year later by using high-spatial-resolution, 1.5-T MR imaging. Studies with unacceptable image quality were excluded. Quantitative changes in atheroma volume were measured on unenhanced T1-weighted images. A multiple linear regression analysis was used to correlate progression with several clinical factors, including statin therapy.

RESULTS

All 160 patients completed both baseline and follow-up studies. Of these studies, 67.5% were deemed to have image quality that was acceptable for quantitative analysis. The causes of rejection were motion (46%), deep location of the carotid artery (22%), low bifurcation of the carotid artery (13%), and "other" (19%). The mean annual change in vessel-wall volume was 2.31% +/- 10.88 (standard deviation) (P = .014). At 1-year follow-up, vessel-wall volumes in patients not receiving statin therapy had increased faster compared with those in patients receiving statin therapy: 7.87% +/- 13.58% vs 1.14% +/- 9.9%, respectively (P = .029).

CONCLUSION

Evaluation of results of a multicenter study indicates that quantitative evaluation of the progression of volume of extracranial carotid vessel walls is feasible with 1.5-T MR imaging despite limitations due to patient motion or habitus. In patients who had preexisting carotid disease, the rate of increase in vessel-wall volume was slower in patients receiving statin therapy.

Computer-assisted diagnosis of prostate cancer using DCE-MRI data: design, implementation and preliminary results

OBJECTS

We present computer-assisted diagnosis (CAD) software designed to improve prostate cancer detection using perfusion MRI data.

METHODS

In addition to standard visualization features, this software allows for the 2D and multislice 2D contouring of suspicious areas based on a seeded region growing algorithm, and area labeling based on zonal anatomy. Tumor volume assessment and the semiquantitative analysis of DCE-MRI sequences can both be performed. We retrospectively analyzed DCE-MRI examinations of 100 patients and found 121 lesions showing a suspiciously high intensity with early enhancement in 84 of them. Seventy-one patients turned out to be malignant, whereas 50 were benign. Based on an analysis of the median wash-in and wash-out values of these foci, we designed a standardized 5-level cancer suspicion score (ranging from "probably benign" to "highly suspicious"). This comprehensive score provides a scaled likelihood of malignancy in the region of interest taking account of its location in relation to prostate zonal anatomy. We compared its accuracy with that of visual assessments of time-intensity curves performed by specialist and non-specialist radiologists.

RESULTS

Parameters of the scoring algorithm were designed to provide the greatest possible sensitivity in our sample population. A re-substitution evaluation provided an Se/Sp of 100/45% for peripheral zone cancer, and 100/40% for transition zone cancer characterization. When identifying malignant areas using time-intensity curves data, this simple algorithm performed significantly better (AUC = 0.77) than a non-specialist (AUC = 0.57, P < 0.0001) radiologist, and better than a trained (AUC = 0.70) radiologist, although this difference was not significant.

CONCLUSION

Our new prostate MRI CAD software provides a standardized cancer suspicion score for suspicious foci detected in DCE-MRI T1-w images. Our results suggest that it may improve radiologists' performances in prostate cancer identification, especially when they are not specialized in prostate imaging.

DicomWorks Teleradiology: secure transmission of medical images over the internet at low cost

We developed a completely secured teleradiology solution tailored for e-mail teleradiology applications at low-cost. Data processing consists in creating a couple of files with an encrypted and compressed image archive and a 128 bits decoding key file. No proprietary file format or encryption scheme is used. Files are exchanged using the e-mail (SMTP and POP) protocols, but FTP or sFTP can be used for better performances. Software includes original features such as real-time interactive JPEG compression, instant archive preview or secured data cleanup when a user logs off. We believe that this flexible, integrated and easy to use solution is a robust alternative to more complex architectures for simple image transmissions or occasional circumstances.

Prostate cancer computer-assisted diagnosis software using dynamic contrast-enhanced MRI

ProCAD is a computer assisted diagnosis (CAD) software dedicated to prostate DCE-MRI analysis.

METHODS

In addition to standard visualization features, 2D and multislice 2D contouring tools based on a seeded growing region algorithm were included in the software. Tumor volume assessment and semiquantitative analysis of suspicious lesions can be performed. A 5-levels cancer suspicion score (ranging from "probably benign" to "Highly suspicious" is calculated on the basis of adjusted parameters extracted from the data of 121 suspicious benign or tumoral lesions.

RESULTS

Using a simple scoring algorithm based the median w.i and w.o values of TZK, TZB, PZK and PZB and designed to provide the highest sensitivity we had respective Se/Sp of 100/49% for peripheral zone cancers, and 100/40% for transition zone cancers characterization.

CONCLUSION

This software provides useful data for an unbiased an reproducible assessment of hypervascularized prostatic areas in routine practice.

Monitoring serial change in the lumen and outer wall of vertebrobasilar aneurysms

BACKGROUND AND PURPOSE

Estimation of the stability of fusiform aneurysms of the basilar artery requires precise monitoring of the luminal and outer wall volumes. In this report we describe the use of MR imaging and 3D postprocessing methods to study the evolution of those aneurysms.

MATERIALS AND METHODS

Nine patients with fusiform basilar artery aneurysms underwent MR imaging studies covering at least 2 different time points (mean delay between studies, 7.1 +/- 4.6 months). Imaging included multisection 2D T1-weighted fast spin-echo and/or 3D steady-state imaging to assess the outer wall and contrast-enhanced MR angiography to study the lumen. The outer and inner walls were extracted using, respectively, a manual delineation (made by 2 observers) and a thresholding technique. The 2 studies were subsequently coregistered at each time point, as well as between differing time points. Volumes of each vessel component were calculated.

RESULTS

Mean volume was 6760 +/- 6620 mm(3) for the outer wall and 2060 +/- 1200 mm(3) for the lumen. Evolution of the lumen and outer wall was highly variable from 1 patient to another, with a trend toward increase of the vessel wall for the largest aneurysms. Interobserver reproducibility for outer wall delineation was on the order of 90%.

CONCLUSION

Combining MR imaging methods to study both the outer wall and lumen with 3D registration tools provides a powerful method for progression of fusiform basilar aneurysmal disease.