Pressure-Insensitive Epidermal Thickness of Fingertip Skin for Optical Image Encryption

In this study, an internal fingerprint-guided epidermal thickness of fingertip skin is proposed for optical image encryption based on optical coherence tomography (OCT) combined with U-Net architecture of a convolutional neural network (CNN). The epidermal thickness of fingertip skin is calculated by the distance between the upper and lower boundaries of the epidermal layer in cross-sectional optical coherence tomography (OCT) images, which is segmented using CNN, and the internal fingerprint at the epidermis-dermis junction (DEJ) is extracted based on the maximum intensity projection (MIP) algorithm. The experimental results indicate that the internal fingerprint-guided epidermal thickness is insensitive to pressure due to normal correlation coefficients and the encryption process between epidermal thickness maps of fingertip skin under different pressures. In addition, the result of the numerical simulation demonstrates the feasibility and security of the encryption scheme by structural similarity index matrix (SSIM) analysis between the original image and the recovered image with the correct and error keys decryption, respectively. The robustness is analyzed based on the SSIM value in three aspects: different pressures, noise attacks, and data loss. Key randomness is valid by the gray histograms, and the average correlation coefficients of adjacent pixelated values in three directions and the average entropy were calculated. This study suggests that the epidermal thickness of fingertip skin could be seen as important biometric information for information encryption.

The guiding value of the cinematic volume rendering technique in the preoperative diagnosis of brachial plexus schwannoma

This study aimed to explore and compare the guiding value of Maximum Intensity Projection (MIP) and Cinematic Volume Rendering Technique (cVRT) in the preoperative diagnosis of brachial plexus schwannomas. We retrospectively analyzed the clinical and imaging data of 45 patients diagnosed with brachial plexus schwannomas at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022. The enhanced three-dimensional short recovery time inversion-recovery fast spin-echo imaging (3D-STIR-SPACE) sequence served as source data for the reconstruction of MIP and cVRT. Two independent observers scored the image quality and evaluated the location of the tumor and the relationship between the tumor and the brachial plexus. The image quality scores of the two reconstruction methods were compared using the nonparametric Wilcoxon signed-rank test, and the consistency between the image and surgical results was assessed using the weighted kappa. Compared to MIP images, cVRT images had a better performance of overall image quality (p < 0.001), nerve and lump visualization (p < 0.001), spatial positional relationship conspicuity (p < 0.001), and diagnostic confidence (p < 0.001). Additionally, the consistency between the cVRT image results and surgical results (kappa =0.913, P<0.001) was higher than that of the MIP images (kappa =0.829, P<0.001). cVRT provides a high guiding value in the preoperative diagnosis of brachial plexus schwannomas and is an important basis for formulating surgical plans.

Maximum intensity projection based on high frame rate contrast-enhanced ultrasound for the differentiation of breast tumors

Objective

We explored the role of maximum intensity projection (MIP) based on high frame rate contrast-enhanced ultrasound (H-CEUS) for the differentiation of breast tumors.

Methods

MIP imaging was performed in patients with breast tumors who underwent H-CEUS examinations. The microvasculature morphology of breast tumors was assessed. The receiver operating characteristic curve was plotted to evaluate the diagnostic performance of MIP.

Results

Forty-three breast tumors were finally analyzed, consisting of 19 benign and 24 malignant tumors. For the ≤30-s and >30-s phases, dot-, line-, or branch-like patterns were significantly more common in benign tumors. A tree-like pattern was only present in the benign tumors. A crab claw-like pattern was significantly more common in the malignant tumors. Among the tumors with crab claw-like patterns, three cases of malignant tumors had multiple parallel small spiculated vessels. There were significant differences in the microvasculature morphology for the ≤30-s and >30-s phases between the benign and malignant tumors (all p < 0.001). The area under the curve, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the ≤30-s phase were all higher than those of the >30-s phase for the classification of breast tumors.

Conclusion

MIP based on H-CEUS can be used for the differentiation of breast tumors, and the ≤30-s phase had a better diagnostic value. Multiple parallel small spiculated vessels were a new finding, which could provide new insight for the subsequent study of breast tumors.

Anatomical Description of Loggerhead Turtle (Caretta caretta) and Green Iguana (Iguana iguana) Skull by Three-Dimensional Computed Tomography Reconstruction and Maximum Intensity Projection Images

The growing interest in reptiles has posed a challenge to veterinary clinicians due to the lack of a standardized system to perform anatomical studies similar to those used for dogs and cats. In this paper, we have attempted to describe, employing computed tomography and subsequent three-dimensional reconstructions, the normal anatomical features that comprise the skulls of two species of reptiles: the loggerhead turtle (Caretta caretta) and the green iguana (Iguana iguana). Computed tomography (CT) and subsequent image processing allowed the identification of the bony structures that comprise the head of these species. As a result, and based on previous articles, we propose the most significant anatomical differences and similarities between these species.

Clinical Significance of Maximum Intensity Projection Method for Diagnostic Imaging of Thoracic Outlet Syndrome

The aim of this study was to use the magnetic resonance imaging maximum-intensity projection (MRI-MIP) method for diagnostic imaging of thoracic outlet syndrome (TOS) and to investigate the stricture ratios of the subclavian artery (SCA), subclavian vein (SCV), and brachial plexus bundle (BP). A total of 113 patients with clinically suspected TOS were evaluated. MRI was performed in a position similar to the Wright test. The stricture was classified into four grades. Then, the stricture ratios of the SCA, SCV, and BP in the sagittal view were calculated by dividing the minimum diameter by the maximum diameter of each structure. Patients were divided into two groups: surgical (n = 22) and conservative (n = 91). Statistical analysis was performed using the Mann-Whitney U test. The stricture level and ratio in the SCV were significantly higher in the surgical group, while the stricture level and the ratio of SCA to BP did not show significant differences between the two groups. The MRI-MIP method may be helpful for both subsidiary and severe diagnoses of TOS.

Is Maximum Intensity Projection an Optimal Approach for Internal Target Volume Delineation in Lung Cancer?

Purpose:

Respiratory-induced tumor motion is a major challenge in lung cancer (LC) radiotherapy. Four-dimensional computed tomography (4D-CT) using a maximum intensity projection (MIP) dataset is a commonly used and time-efficient method to generate internal target volume (ITV). This study compared ITV delineation using MIP or tumor delineation on all phases of the respiratory cycle.

Materials and Methods:

Thirty consecutive patients of LC who underwent 4D-CT from January 2014 to March 2017 were included. ITV delineation was done using MIP (ITV_MIP) and all ten phases of the respiratory cycle (ITV_10Phases). Both volumes were analyzed using matching index (MI). It is the ratio of the intersection of two volumes to the union of two volumes. A paired sample t-test was used for statistical analysis, and P < 0.05 was considered statistically significant.

Results:

The mean ± standard deviation volume of ITV_10Phases was significantly larger compared to ITV_MIP (134 cc ± 39.1 vs. 113 cc ± 124.2, P = 0.000). The mean MI was 0.75 (range 0.57–0.88). The mean volume of ITV_10Phases not covered by ITV_MIP was 26.33 cc (23.5%) and vice versa was 5.51 cc (6.1%). The mean MI was 0.73 for tumors close to the mediastinum, chest wall, and diaphragm. MI was not different between tumors ≤5 cm and >5 cm. The average time required for delineation was 9 and 96 min, respectively. The center of mass of two ITVs differed by 0.01 cm.

Conclusion:

ITV using MIP is significantly smaller and may miss a tumor compared to ITV delineation in 10 phases of 4D-CT. However, the time required is significantly less with MIP. Caution should be exercised in tumors proximity to the mediastinum, chest wall, and diaphragm.

Maximum intensity projection aids in diagnosing acute appendicitis and mobile caecum: A case report and literature review

Appendicitis is a common childhood condition requiring surgical intervention and delayed diagnosis can have serious consequences. This report describes the case of a child who presented with an acute abdomen and intestinal obstruction. Multidetector (MD) CT demonstrated a left-sided caecum and an inflamed appendix with a faecolith. Maximum intensity projection (MIP) post-processing was key in identifying the appendicular artery and determine the diagnosis. At surgery, however, a mobile caecum and the appendix were positioned on the right side.

Comparison of Maximum Intensity Projection and Volume Rendering in Detecting Pulmonary Nodules on Multidetector Computed Tomography

Introduction Lung cancer is the most common cancer overall, and the foremost cause of cancer-related mortality. Almost all lung cancers evolve from pulmonary nodules. As multidetector CT (MDCT) scanners are now widely available, there is an increased rate of detection of pulmonary nodules. It is of utmost importance to evaluate pulmonary nodules to rule out the possibility of neoplastic diseases. With advancements in technology, there are various manual and automatic analytic software providing a wide range of post-processing techniques. Maximum intensity projection (MIP) and volume rendering (VR) techniques have been analyzed previously regarding pulmonary nodules but there is a scarcity of data in terms of low-density nodules. This study aims to delineate the comparison and supremacy of both techniques in terms of low-density nodules. Methodology The current prospective study was conducted from June 2019 to June 2020 in the Radiology Department at Dr. Ziauddin Hospital, Karachi. Chest CT scans were performed on 16 slice MDCT (Alexion 16 Multi-slice, Toshiba Medical System Corporation, Houston, TX). A consultant radiologist of six years experience and a postgraduate trainee of three years experience analyzed each patient on a workstation (Vitrea 6.2.0, Vital Images, Minnetonka, MN). SPSS 23.0 (SPSS Inc., Chicago, IL) was incorporated for data analysis. Data were expressed in the median and interquartile range (IQR). Data collected for this study were analyzed using analyzing the median difference in nodule count using Wilcoxon's signed-rank test. A p-value of <0.05 was considered significant. Results After informed consent, 236 patients were recruited for the study. MIP outperformed VR in terms of nodule detection and low-density nodules at each evaluated slab thicknesses (p<0.001). A 10-mm MIP was superior to all other techniques in terms of detection of pulmonary nodules and low-density nodules (p<0.001). MIP was also considered an easier technique as there was excellent inter-rater reliability and agreement. Conclusion This study is robust evidence regarding the supremacy of MIP. MIP outperformed VR on every slab thicknesses. The 10-mm MIP technique was superior to all others evaluated and was recorded to be an easier analyzing technique.

Role of CT Imaging With Three-Dimensional Maximum Intensity Projection Reconstruction in the Evaluation of Portal Vein Variants at a Tertiary Care Hospital

INTRODUCTION

Portal vein (PV) is the principal blood vessel transporting blood from the alimentary tract and spleen to the liver. The aim of this study is to determine the prevalence of PV anatomical variations in our population using multidetector CT with maximum intensity projection (MIP) technique at a tertiary care hospital.

METHODS

This cross-sectional study was prospectively conducted from November 2018 to June 2019 in the Department of Radiology at a tertiary care hospital in Karachi. After informed consent, all the patients with no known hepatic pathology undergoing routine abdomen CT were included in this study. Patients with previous hepatic resection surgeries, undiagnosed large hepatic tumors/metastasis, and those with PV thrombosis were excluded.

RESULTS

A total of 500 patients (256 males and 244 females) were included in the study; the mean age of female patients was relatively higher as compared to the male patients (53.80 ± 18.44 vs. 44.15 ± 19.94 years; p = 0.000). Standard PV anatomy (type 1) was found in 438 patients (87.6%). Trifurcation (type 2) occurred in 18 patients (3.6%). Right posterior portal vein as the first branch of main PV (type 3) was found in 22 patients (4.4%). A separate branch of the right portal vein (RPV) to segment VII (type 4) and separate branch of the RPV to segment VI (type 5) were found in 6 (1.2%) and 16 (3.2%) patients, respectively.

CONCLUSION

Our study displayed a relatively higher frequency of standard PV anatomy (type 1) compared to previous studies. We highlight the role of MIP in the analysis of hepatic venous anatomy with its utility demonstrating improved detection of variations.

Diagnostic Accuracy of Maximum Intensity Projection in Diagnosis of Malignant Pulmonary Nodules

Introduction Pulmonary nodules are frequently encountered during chest imaging, and its evaluation is usually done by chest radiograph and computed tomography (CT) scan of chest. High resolution of multidetector CT (MDCT) has improved the nodule detection. Post processing techniques such as maximum intensity projection (MIP) can further improve the sensitivity of MDCT for nodule detection. Failure to diagnose malignancy in pulmonary nodules can delay the treatment. Therefore, the aim of this study was to determine the diagnostic accuracy of MIP in the diagnosis of malignant pulmonary nodules taking histopathology findings as gold standard. Materials and methods A retrospective cross-sectional study was conducted at Dow Institute of Radiology, Dow University of Health Sciences, from 1 December 2018 till 30 June 2019. Both male and female patients aged 18 years and above who underwent CT scan of chest with suspicion of pulmonary nodules were included. Patients already diagnosed with malignant pulmonary nodules and presenting for follow-up were excluded. Contrast-enhanced CT chest was performed on a multi-slice scanner. MIP reconstruction and evaluation was performed on the workstation. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of MIP were calculated taking histopathology findings as gold standard. Results A total of 202 patients were included in this study. The mean age of the patients was 55.87 ± 13.08 years. A total of 103 patients (51.0%) were males and 99 patients (49.0%) were females. There were 131 (64.9%) nodules with smooth margins and 71 (35.1%) nodules with irregular margins. The mean size of nodule was 3.1 ± 0.7 cm. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of MIP in diagnosing malignant pulmonary nodules were found to be 85.82%, 82.35%, 90.55%, 74.67%, and 84.65%, respectively, taking histopathology findings as gold standard. The nodules >3 cm in size had a higher sensitivity for diagnosing malignant pulmonary nodules. Smooth margin nodule had high sensitivity, specificity, and diagnostic accuracy for diagnosing malignant pulmonary nodules. Conclusion MIP images have high sensitivity, specificity, and diagnostic accuracy in the diagnosis of malignant pulmonary nodules. The utilization of MIP images can aid in the detection of malignant pulmonary nodules and help in formulating early treatment strategies for the patients. Other post processing techniques such as volume rendering and computer-aided detection can help in further improving patient care.

Use of clinical MRI maximum intensity projections for improved breast lesion classification with deep convolutional neural networks

Deep learning methods have been shown to improve breast cancer diagnostic and prognostic decisions based on selected slices of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). However, incorporation of volumetric and temporal components into DCE-MRIs has not been well studied. We propose maximum intensity projection (MIP) images of subtraction MRI as a way to simultaneously include four-dimensional (4-D) images into lesion classification using convolutional neural networks (CNN). The study was performed on a dataset of 690 cases. Regions of interest were selected around each lesion on three MRI presentations: (i) the MIP image generated on the second postcontrast subtraction MRI, (ii) the central slice of the second postcontrast MRI, and (iii) the central slice of the second postcontrast subtraction MRI. CNN features were extracted from the ROIs using pretrained VGGNet. The features were utilized in the training of three support vector machine classifiers to characterize lesions as malignant or benign. Classifier performances were evaluated with fivefold cross-validation and compared based on area under the ROC curve (AUC). The approach using MIPs [Formula: see text] outperformed that using central-slices of either second postcontrast MRIs [Formula: see text] or second postcontrast subtraction MRIs [Formula: see text], at statistically significant levels.

Maximum-Intensity-Projection and Computer-Aided-Detection Algorithms as Stand-Alone Reader Devices in Lung Cancer Screening Using Different Dose Levels and Reconstruction Kernels

OBJECTIVE

The objective of our study was to evaluate lung nodule detection rates on standard and microdose chest CT with two different computer-aided detection systems (SyngoCT-CAD, VA 20, Siemens Healthcare [CAD1]; Lung CAD, IntelliSpace Portal DX Server, Philips Healthcare [CAD2]) as well as maximum-intensity-projection (MIP) images. We also assessed the impact of different reconstruction kernels.

MATERIALS AND METHODS

Standard and microdose CT using three reconstruction kernels (i30, i50, i70) was performed with an anthropomorphic chest phantom. We placed 133 ground-glass and 133 solid nodules (diameters of 5 mm, 8 mm, 10 mm, and 12 mm) in 55 phantoms. Four blinded readers evaluated the MIP images; one recorded the results of CAD1 and CAD2. Sensitivities for CAD and MIP nodule detection on standard dose and microdose CT were calculated for each reconstruction kernel.

RESULTS

Dose for microdose CT was significantly less than that for standard-dose CT (0.1323 mSv vs 1.65 mSv; p < 0.0001). CAD1 delivered superior results compared with CAD2 for standard-dose and microdose CT (p < 0.0001). At microdose level, the best stand-alone sensitivity (97.6%) was comparable with CAD1 sensitivity (96.0%; p = 0.36; both with i30 reconstruction kernel). Pooled sensitivities for all nodules, doses, and reconstruction kernels on CAD1 ranged from 88.9% to 97.3% versus 49.6% to 73.9% for CAD2. The best sensitivity was achieved with standard-dose CT, i50 kernel, and CAD1 (97.3%) versus 96% with microdose CT, i30 or i50 kernel, and CAD1. MIP images and CAD1 had similar performance at both dose levels (p = 0.1313 and p = 0.48).

CONCLUSION

Submillisievert CT is feasible for detecting solid and ground-glass nodules that require soft-tissue kernels for MIP and CAD systems to achieve acceptable sensitivities. MIP reconstructions remain a valuable adjunct to the interpretation of chest CT for increasing sensitivity and have the advantage of significantly lower false-positive rates.

Distinguishing high-flow from low-flow vascular malformations using maximum intensity projection images in dynamic magnetic resonance angiography - comparison to other MR-based techniques

BACKGROUND

In addition to ultrasound, magnetic resonance imaging (MRI) is considered a suitable, non-invasive technique to assess the type and extent of vascular malformations. The distinction between low- and high-flow lesions is crucial because it determines appropriate patient treatment.

PURPOSE

To distinguish high-flow from low-flow lesions on the basis of the enhancement pattern on MIP images acquired from dynamic time-resolved MR angiography (MRA) and compare it with previously described MR-based methods.

MATERIAL AND METHODS

We examined 25 consecutive patients with previously diagnosed vascular malformations. Next, each malformation was classified as "high-flow" or "low-flow" using the following criteria: (i) findings on T1-weighted (T1W) and T2-weighted (T2W) imaging (signal voids, signal intensity); (ii) the time interval between the start of arterial enhancement and the onset of lesion enhancement (artery-lesion time); (iii) the time of maximum lesion enhancement; and (iv) analysis of the slope of the enhancement curve.

RESULTS

Of the 25 patients, seven had high-flow and 18 had low-flow malformations. Signal voids on spin-echo T1W images were observed only in four of seven high-flow malformations and in two of 18 low-flow malformations. Analysis of signal intensity on T2W images showed increased signal intensity in 17 of 18 low-flow malformations, and in two of seven high-flow lesions. Calculation of the artery-lesion time, maximum enhancement time, and slope revealed significant differences between the high- and low-flow groups.

CONCLUSION

In conclusion, the slope of the enhancement curve appears to be useful in distinguishing between high- and low-flow vascular malformations. Standardization of MR image evaluation criteria is essential.

Improved image reconstruction of low-resolution multichannel phase contrast angiography

In low-resolution phase contrast magnetic resonance angiography, the maximum intensity projected channel images will be blurred with consequent loss of vascular details. The channel images are enhanced using a stabilized deblurring filter, applied to each channel prior to combining the individual channel images. The stabilized deblurring is obtained by the addition of a nonlocal regularization term to the reverse heat equation, referred to as nonlocally stabilized reverse diffusion filter. Unlike reverse diffusion filter, which is highly unstable and blows up noise, nonlocal stabilization enhances intensity projected parallel images uniformly. Application to multichannel vessel enhancement is illustrated using both volunteer data and simulated multichannel angiograms. Robustness of the filter applied to volunteer datasets is shown using statistically validated improvement in flow quantification. Improved performance in terms of preserving vascular structures and phased array reconstruction in both simulated and real data is demonstrated using structureness measure and contrast ratio.

Comparison of primary tumour volumes delineated on four-dimensional computed tomography maximum intensity projection and (18) F-fluorodeoxyglucose positron emission tomography computed tomography images of non-small cell lung cancer

INTRODUCTION

The study aims to compare the positional and volumetric differences of tumour volumes based on the maximum intensity projection (MIP) of four-dimensional CT (4DCT) and (18) F-fluorodexyglucose ((18) F-FDG) positron emission tomography CT (PET/CT) images for the primary tumour of non-small cell lung cancer (NSCLC).

METHODS

Ten patients with NSCLC underwent 4DCT and (18) F-FDG PET/CT scans of the thorax on the same day. Internal gross target volumes (IGTVs) of the primary tumours were contoured on the MIP images of 4DCT to generate IGTVMIP . Gross target volumes (GTVs) based on PET (GTVPET ) were determined with nine different threshold methods using the auto-contouring function. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTVPET and IGTVMIP were investigated.

RESULTS

In volume terms, GTVPET 2.0 and GTVPET 20% approximated closely to IGTVMIP with mean volume ratio of 0.93 ± 0.45 and 1.06 ± 0.43, respectively. The best MI was between IGTVMIP and GTVPET 20% (0.45 ± 0.23). The best DI of IGTVMIP in GTVPET was IGTVMIP in GTVPET 20% (0.61 ± 0.26).

CONCLUSIONS

In 3D PET images, the GTVPET contoured by standardised uptake value (SUV) 2.0 or 20% of maximal SUV (SUVmax ) approximate closely to the IGTVMIP in target size, while the spatial mismatch is apparent between them. Therefore, neither of them could replace IGTVMIP in spatial position and form. The advent of 4D PET/CT may improve the accuracy of contouring the perimeter for moving targets.

Geometrical differences in target volumes based on 18F-fluorodeoxyglucose positron emission tomography/computed tomography and four-dimensional computed tomography maximum intensity projection images of primary thoracic esophageal cancer

The objective of the study was to compare geometrical differences of target volumes based on four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of primary thoracic esophageal cancer for radiation treatment. Twenty-one patients with thoracic esophageal cancer sequentially underwent contrast-enhanced three-dimensional computed tomography (3DCT), 4DCT, and 18F-FDG PET/CT thoracic simulation scans during normal free breathing. The internal gross target volume defined as IGTVMIP was obtained by contouring on MIP images. The gross target volumes based on PET/CT images (GTVPET ) were determined with nine different standardized uptake value (SUV) thresholds and manual contouring: SUV≥2.0, 2.5, 3.0, 3.5 (SUVn); ≥20%, 25%, 30%, 35%, 40% of the maximum (percentages of SUVmax, SUVn%). The differences in volume ratio (VR), conformity index (CI), and degree of inclusion (DI) between IGTVMIP and GTVPET were investigated. The mean centroid distance between GTVPET and IGTVMIP ranged from 4.98 mm to 6.53 mm. The VR ranged from 0.37 to 1.34, being significantly (P<0.05) closest to 1 at SUV2.5 (0.94), SUV20% (1.07), or manual contouring (1.10). The mean CI ranged from 0.34 to 0.58, being significantly closest to 1 (P<0.05) at SUV2.0 (0.55), SUV2.5 (0.56), SUV20% (0.56), SUV25% (0.53), or manual contouring (0.58). The mean DI of GTVPET in IGTVMIP ranged from 0.61 to 0.91, and the mean DI of IGTVMIP in GTVPET ranged from 0.34 to 0.86. The SUV threshold setting of SUV2.5, SUV20% or manual contouring yields the best tumor VR and CI with internal-gross target volume contoured on MIP of 4DCT dataset, but 3DPET/CT and 4DCT MIP could not replace each other for motion encompassing target volume delineation for radiation treatment.

Oncologic PET/CT interpretation and reporting approaches. Survey in clinical practice

AIM

To elucidate techniques most commonly used for interpreting oncologic PET/CT studies. This survey forms a basis to work on standardization of reporting and highlight the most important issues to be addressed.

METHODS

A web-based survey of 329 PET/CT imaging specialists was designed with the intent to determine image interpretation patterns. The questionnaire consisted of 19 questions. Of the 329 participants, 230 were nuclear medicine specialists, 46 were radiologists, and 53 had dual-board certification.

RESULTS

Report ofstandardized uptake values (SUV) is not consistent;only50.2% of respondents always report SUVs, while 45.2% report only if needed or requested. 80.9% of respondents indicated that reporting of SUV is only appropriate when its limitations are understood whereby a large majority prefer to report SUVmax. Maximum intensity projection (MIP) images are almost always reviewed by 91.1% of the respondents. An accurate and detailed clinical history is considered an essential element for reading PET/CT studies by 84.0%, but only 20.7% report that this is always available. The most common self-reported average time for reviewing and reporting of whole body PET/CT (with no prior comparison scan) was 15-20 min (27.5%).

CONCLUSION

PET readers have considerable reservations regarding the use and reporting of SUVs. SUVmax is more frequently used than SUVmean. Evaluation of MIP images is considered an important element of PET/CT interpretation. Although availability of sufficient patient's history is considered essential, this is rarely available.

Dietary cholesterol increases ventricular volume and narrows cerebrovascular diameter in a rabbit model of Alzheimer's disease

Using structural magnetic resonance imaging in a clinical scanner at 3.0T, we describe results showing that following 12weeks on a diet of 2% cholesterol, rabbits experience a significant increase in the volume of the third ventricle compared to rabbits on a diet of 0% cholesterol. Using time-of-flight magnetic resonance angiography, we find cholesterol-fed rabbits also experience a decrease in the diameter of a number of cerebral blood vessels including the basilar, posterior communicating, and internal carotid arteries. Taken together, these data confirm that, despite the inability of dietary cholesterol to cross the blood-brain barrier, it does significantly enlarge ventricular volume and decrease cerebrovascular diameter in the rabbit - effects that are also seen in patients with Alzheimer's disease.

Correlation between secretin-enhanced MRCP findings and histopathologic severity of chronic pancreatitis in a cat model

BACKGROUND/OBJECTIVES

To evaluate the usefulness of secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) in chronic pancreatitis (CP), we compared the severity of disease determined histopathologically with that indicated by S-MRCP imaging parameters in an induced CP cat model.

MATERIALS AND METHODS

An experimental group of randomly chosen cats (n = 24) underwent ligation of the pancreatic duct to induce CP, and cats in a similarly chosen control group (n = 8) were sham-operated. MRCP was performed prior to secretin stimulation, and 5 and 15 min afterward, noting in particular the pancreatic duct caliber change (PDC) and the increasing degree of fluid volume (IDFV). Histopathological changes were observed in pancreatic samples processed for hematoxylin-eosin and Sirius red staining, and CP was classified as normal, minimal, moderate, or advanced. Correlations were investigated between these groups and the PDC at 5 min and the IDFV at 15 min.

RESULTS

Between cats with minimal CP and the controls, the differences in mean IDFV and PDC were not significant although diseased cats showed a downward trend in both parameters. However, compared with the control group both the mean IDFV and PDC were significantly lower in cats with moderate (IDFV, P = 0.001; PDC, P = 0.013) or advanced (IDFV, P = 0.013; PDC, P = 0.001) CP.

CONCLUSION

The S-MRCP parameters IDFV and PDC correlated with the histopathological severity of induced CP. S-MRCP could be used to evaluate the severity of CP, although it is somewhat insensitive for depicting very early disease.

GPU-based real-time volumetric ultrasound image reconstruction for a ring array

Synthetic phased array (SPA) beamforming with Hadamard coding and aperture weighting is an optimal option for real-time volumetric imaging with a ring array, a particularly attractive geometry in intracardiac and intravascular applications. However, the imaging frame rate of this method is limited by the immense computational load required in synthetic beamforming. For fast imaging with a ring array, we developed graphics processing unit (GPU)-based, real-time image reconstruction software that exploits massive data-level parallelism in beamforming operations. The GPU-based software reconstructs and displays three cross-sectional images at 45 frames per second (fps). This frame rate is 4.5 times higher than that for our previously-developed multi-core CPU-based software. In an alternative imaging mode, it shows one B-mode image rotating about the axis and its maximum intensity projection, processed at a rate of 104 fps . This paper describes the image reconstruction procedure on the GPU platform and presents the experimental images obtained using this software.

Quantitative evaluation of high intensity signal on MIP images of carotid atherosclerotic plaques from routine TOF-MRA reveals elevated volumes of intraplaque hemorrhage and lipid rich necrotic core

BACKGROUND

Carotid intraplaque hemorrhage (IPH) and lipid rich necrotic core (LRNC) have been associated with accelerated plaque growth, luminal narrowing, future surface disruption and development of symptomatic events. The aim of this study was to evaluate the quantitative relationships between high intensity signals (HIS) in the plaque on TOF-MRA and IPH or LRNC volumes as measured by multicontrast weighted CMR.

METHODS

Seventy six patients with a suspected carotid artery stenosis or carotid plaque by ultrasonography underwent multicontrast carotid CMR. HIS presence and volume were measured from TOF-MRA MIP images while IPH and LRNC volumes were separately measured from multicontrast CMR.

RESULTS

For detecting IPH, HIS on MIP images overall had high specificity (100.0%, 95% CI: 93.0 - 100.0%) but relatively low sensitivity (32%, 95% CI: 20.8 - 47.9%). However, the sensitivity had a significant increasing relationship with underlying IPH volume (p = 0.033) and degree of stenosis (p = 0.022). Mean IPH volume was 2.7 times larger in those with presence of HIS than in those without (142.8 ± 97.7 mm(3) vs. 53.4 ± 56.3 mm(3), p = 0.014). Similarly, mean LRNC volume was 3.4 times larger in those with HIS present (379.8 ± 203.4 mm(3) vs. 111.3 ± 122.7 mm(3), p = 0.001). There was a strong correlation between the volume of the HIS region and the IPH volume measured from multicontrast CMR (r = 0.96, p < 0.001).

CONCLUSION

MIP images are easily reformatted from three minute, routine, clinical TOF sequences. High intensity signals in carotid plaque on TOF-MRA MIP images are associated with increased intraplaque hemorrhage and lipid-rich necrotic core volumes. The technique is most sensitive in patients with moderate to severe stenosis.

CT Manifestations of Osler-Weber-Rendu Syndrome in Liver: Report of Three Cases

Osler-Weber-Rendu syndrome is characterized by widespread telangiectasias. Its clinical manifestations depend on position and scope of the abnormal vessels. The clinical and CT data of 3 patients with Osler-Weber-Rendu syndrome were retrospectively analyzed. CT features reviewed include the change of volume and configuration of liver, presence of tortuous and irregular vessels, opacified vessel mass, arteriovenous shunt, and splenomegaly. CT is helpful for diagnosis, treatment, and follow-up of Osler-Weber-Rendu syndrome.

3D multidetector CT angiographic evaluation of intralobular bronchopulmonary sequestration

We report a case of intralobar pulmonary sequestration with special emphasis on computed tomography (CT) angiography in determining the arterial supply and venous drainage, thus providing a detailed knowledge of the vasculature, which is of vital importance in surgery. The 3D volume rendering technique and maximum intensity projection images provide the vascular road map for the surgeon.

A method for rapid computation of maximum intensity projection images

We describe a method for rapid calculation of maximum intensity projection (MIP) images. The method is applied to 10 example cases with more extensive testing in 1 case. Measurements of calculation time for all 10 cases show good performance (less than 1.2 seconds) for calculating a MIP image that is a very faithful representation of the original (less than 2% of pixels differ from original image). We also demonstrate that the computation time is related linearly to the number of pixels used, allowing arbitrarily rapid computation rates. This technique may be helpful as a navigation aid in evaluation magnetic resonance (MR) angiography data.