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The objective of this study is to evaluate the feasibility of a disease-specific deep learning (DL) model based on minimum intensity projection (minIP) for automated emphysema detection in low-dose computed tomography (LDCT) scans. LDCT scans of 240 individuals from a population-based cohort in the Netherlands (ImaLife study, mean age ± SD = 57 ± 6 years) were retrospectively chosen for training and internal validation of the DL model. For independent testing, LDCT scans of 125 individuals from a lung cancer screening cohort in the USA (NLST study, mean age ± SD = 64 ± 5 years) were used. Dichotomous emphysema diagnosis based on radiologists’ annotation was used to develop the model. The automated model included minIP processing (slab thickness range: 1 mm to 11 mm), classification, and detection maps generation. The data-split for the pipeline evaluation involved class-balanced and imbalanced settings. The proposed DL pipeline showed the highest performance (area under receiver operating characteristics curve) for 11 mm slab thickness in both the balanced (ImaLife = 0.90 ± 0.05) and the imbalanced dataset (NLST = 0.77 ± 0.06). For ImaLife subcohort, the variation in minIP slab thickness from 1 to 11 mm increased the DL model’s sensitivity from 75 to 88% and decreased the number of false-negative predictions from 10 to 5. The minIP-based DL model can automatically detect emphysema in LDCTs. The performance of thicker minIP slabs was better than that of thinner slabs. LDCT can be leveraged for emphysema detection by applying disease specific augmentation.

Background: Evaluation of the diagnostic value of computed tomography (CT) cholangiography with minimum intensity projection (MinIP) in the work up of patients with obstructive biliary disease through correlation with percutaneous trans hepatic cholangiography (PTC) results. Objective: In this study, we aimed to evaluate the diagnostic value of CT cholangiography with MinIP in the work up of patients with obstructive biliary disease through correlation with PTC results. Patients and Method: The study included 36 patients (26 males and 10 females), with biliary obstruction. CT cholangiography was done to reach a definite diagnosis for the cause of obstruction and PTC was done during their management plan. Analysis of the image data with (MinIP) images was created on a separate workstation and compared to that of PTC. Results: The CT cholangiography using MinIP technique correctly diagnosed the cause of obstruction among all included cases. No significant difference was found between measurements of obstructing lesion size. We had a novel observation about that axial images are significantly better to reveal the obstructing biliary lesion if the cause of obstruction is intrahepatic; while coronal images are significantly better to reveal the obstructing biliary lesion if the cause of obstruction is extrahepatic. Conclusion: CT cholangiography with MinIP is a complete noninvasive technique that provides projectional images similar to that of PTC without administration of oral specific contrast agents, requires no medications, less operator dependent and no complications were encountered in adequately screened patients.

In digital in-line particle holography (DIPH), minimum intensity projection (MIP) is a crucial step in the reconstruction procedure, the MIP image quality is significantly degraded by nonuniform-il...

Hepatic portal venous gas and pneumobilia (PB) are uncommon findings, indicating the accumulation of gas in the portal vein and its branches and in the biliary tree, respectively. Aims of this retrospective, descriptive study were to describe the computed tomographic (CT) features and visualization techniques of hepatic portal venous gas (HPVG) and PB in a group of small animal veterinary patients. The CT data of patients with HPVG and PB were retrospectively reviewed. Thin-section multiplanar reformatting and minimum intensity projection (MinIP) views were used to assess the acquired volume dataset. The CT features recorded were as follows: amount, aspect, distribution, and localization of the gas in the liver. Five patients were included (four dogs and one cat), two presenting HPVG and three with PB. Gas in HPVG presented a peripheral location, whereas in PB was characterized by a central location. The aspect of the gas was tubular in case of HPVG and mixed tubular and rounded in PB. An analogous number of animals between the two groups showed comparable amount (mild, moderate, and severe) and distribution (diffuse and focal). Thin-section CT can detect the presence of gas in the liver, and a combination of two-dimensional and thin-slab MinIP can differentiate between HPVG and PB in dogs and cats. The distinctive features are peripheral versus central location and tubular versus rounded aspect of the gas.

OBJECTIVE. The purpose of this study was to investigate the effect of slab thickness on the detection of pulmonary nodules by use of maximum-intensity-projection (MIP) and minimum-intensity-projection (MinIP) to process CT images. MATERIALS AND METHODS. Chest CT data of 221 patients with pulmonary nodules were retrospectively analyzed. Nodules were categorized into two groups according to density: solid nodules (SNs) and subsolid nodules (SSNs). Pulmonary nodules were independently evaluated by two radiologists using axial CT images with 1-mm and 5-mm section thickness and MIP and MinIP images. MIP images for SN detection and MinIP images for SSN detection were separately reconstructed with four (5, 10, 15, 20 mm) and three (3, 8, 15 mm) slab thicknesses. The numbers and locations of detected nodules were recorded, and interobserver agreement was assessed. For each reader, the differences in nodule detection rates were evaluated in different series of images. RESULTS. Among the different series of images, interobserver agreements for detecting nodules were all good to excellent (κ ≥ 0.687). For total SNs and SNs with a diameter < 5 mm, detection rates on 10-mm MIP images were significantly higher than in other series of images (reader 1, 84.5% and 83.8%; reader 2, 83.6% and 82.2%). For total SSNs and SSNs < 5 mm, detection rates on 3-mm MinIP images were significantly higher than those in other series of images, except for 1-mm (reader 1, 93.3% and 78.6%; reader 2, 95.0% and 81.0%). CONCLUSION. Ten-millimeter MIP images are extremely efficient for detecting SNs. Three-millimeter MinIP images are more useful for visualizing SSNs, the efficiency being comparable to that achieved by use of 1-mm axial images.

Post mortem computed tomography (PMCT) can aid in localizing foreign bodies, bone fractures, and gas accumulations. The visualization of these findings play an important role in the communication of radiological findings. In this article, we present an algorithm for automated visualization of gas distributions on PMCT image data of the thorax and abdomen. The algorithm uses a combination of region growing segmentation and layering of different visualization methods to automatically generate overview images that depict radiopaque foreign bodies, bones and gas distributions in one image. The presented method was tested on 955 PMCT scans of the thorax and abdomen. The algorithm managed to generate useful images for all cases, visualizing foreign bodies as well as gas distribution. The most interesting cases are presented in this article. While this type of visualization cannot replace a real radiological analysis of the image data, it can provide a quick overview for briefings and image reports.

PURPOSE: To investigate whether minimum intensity projection (MinIP) reconstructions enable more accurate depiction of pulmonary ground-glass opacity (GGO) compared to standard transverse sections and multiplanar reformat (MPR) series in patients with suspected coronavirus disease 2019 (COVID-19). METHOD: In this multinational study, chest CT scans of 185 patients were retrospectively analyzed. Diagnostic accuracy, diagnostic confidence, image quality regarding the assessment of GGO, as well as subjective time-efficiency of MinIP and standard MPR series were analyzed based on the assessment of six radiologists. In addition, the suitability for COVID-19 evaluation, image quality regarding GGO and subjective time-efficiency in clinical routine was assessed by five clinicians. RESULTS: The reference standard revealed a total of 149 CT scans with pulmonary GGO. MinIP reconstructions yielded significantly higher sensitivity (99.9 % vs 95.6 %), specificity (95.8 % vs 86.1 %) and accuracy (99.1 % vs 93.8 %) for assessing of GGO compared with standard MPR series. MinIP reconstructions achieved significantly higher ratings by radiologists concerning diagnostic confidence (medians, 5.00 vs 4.00), image quality (medians, 4.00 vs 4.00), contrast between GGO and unaffected lung parenchyma (medians, 5.00 vs 4.00) as well as subjective time-efficiency (medians, 5.00 vs 4.00) compared with MPR-series (all P < .001). Clinicians preferred MinIP reconstructions for COVID-19 assessment (medians, 5.00 vs 3.00), image quality regarding GGO (medians, 5.00 vs 3.00) and subjective time-efficiency in clinical routine (medians, 5.00 vs 3.00). CONCLUSIONS: MinIP reconstructions improve the assessment of COVID-19 in chest CT compared to standard images and may be suitable for routine application.

With 6 years of experience in implementing virtopsy routinely into the Hong Kong cetacean stranding response program, standardized virtopsy procedures, postmortem computed tomography (PMCT) acquisition, postprocessing, and evaluation were successfully established. In this pioneer cetacean virtopsy stranding response program, PMCT was performed on 193 stranded cetaceans, providing postmortem findings to aid necropsy and shed light on the biological health and profile of the animals. This study aimed to assess 8 image rendering techniques in PMCT, including multiplanar reconstruction, curved planar reformation, maximum intensity projection, minimum intensity projection, direct volume rendering, segmentation, transfer function, and perspective volume rendering. Illustrated with practical examples, these techniques were able to identify most of the PM findings in stranded cetaceans and served as a tool to investigate their biological health and profile. This study could guide radiologists, clinicians and veterinarians through the often difficult and complicated realm of PMCT image rendering and reviewing.

The aim of the study Is to compare the role of minimum intensity projection (MinIP) images with that of volumetric high resolution computed tomography (HRCT) images in the diagnosis of interstitial lung diseases (ILD). Patients and methods 180 patients (149 females and 31 males) were included in this prospective study that took place over a duration of two and half years. All patients underwent HRCT and MinIP images. The positive findings were compared recording which technique was better and if MinIP adds a value in reaching an accurate diagnosis. Results MinIP images showed better visualization of traction bronchiectasis, ground glass opacities and mosaic attenuation pattern, as well as, the cystic lung changes seen in LAM. While MinIP did not add a significant value in thick-walled cystic changes e.g.: honeycombing. Conclusion MinIP is one of the multiplanar techniques of HRCT that proved throughout our study to be an informative complementary tool increasing the observer confidence and agreement regarding some findings as compared with HRCT alone.

Background: Minimum Intensity Projection is a post-proccesing technique on CT Scan that useful for showing structures with low Hounsfiled Unit (HU) values such as pancreas. To demonstrate the anatomy and pathology of the pancreatic organs, a contrast CT scan was performed on pancreatic phase but pancreatic phase was rarely used, so it was replaced by the portal venous phase, but this technique is still rarely used among the radiographers. Objective: This study aimed to prove the image of the portal venous pancreatic vein on contrast contrast CT scan by using minimum intensity projection (MinIP) on CT scan 64 slices will produce a more optimal image than without the minimum intensity projection (MinIP). Methods: This study is a retrospective study with an observational analytic method to assess differences of pancreatic image in contrasting contrast CT scans with and with MinIP reforms on CT 64 slice modalities Philips Briliance. 30 images as samples, with the criteria set by the researchers. The image will be post proccesing without and by using MinIP reformat. Image results will be evaluated by two radiologist, then the data obtained will be tabulated and processed using SPSS software version 17. Result: From this research obtained the result that MinIP reformat able to produce pancreas image more optimal than image without MinIP reformat on CT scan 64 slice and shows a significant difference. Overall assessment of the image has an improvement with the MinIP but for the homogeneity of pancreatic images decreased. Conclusions: There was a significant difference between pancreatic venous porta port results in contrasting CT scans of the abdomen without and with MinIP reformat.

Objective: This study investigated the diagnostic performance of MinIP images based on three-dimensional variable-flip-angle turbo spin echo T1 weighted imaging (3D CUBE T1WI) from high-resolution vessel wall magnetic resonance imaging for detecting middle cerebral artery (MCA) stenosis. Methods: A total of 63 consecutive patients were included in this study. MinIP images were reconstructed using 3D CUBE T1WI as the source images. The degree and length of MCA stenosis were measured on MinIP images and were compared with digital subtraction angiography (DSA) as the reference standard. Results: The intra- and interobserver agreement for both the rate and length of MCA stenosis were excellent for the MinIP images. There was also excellent agreement in the degree of MCA stenosis calculated using MinIP images and DSA. MinIP images had a high sensitivity, specificity for diagnosing MCA stenosis. There was a good correlation between the two methods for measuring the rate and length of MCA stenosis. Conclusion: MinIP images based on 3D CUBE T1WI are highly consistent with DSA for evaluating the degree and length of MCA stenosis. Advances in knowledge: MinIP images can be produced as a derivative from vessel wall imaging and implemented as an adjunct to vessel wall imaging without extra acquisition time.

Objective Intraocular foreign body (IOFB), a frequent cause of ocular trauma, causes serious damage to the eyes. This study was designed to elaborate and compare the characteristics of different magnetic resonance imaging (MRI) sequences in detecting wooden IOFBs in rabbits. Methods The right vitreous of 24 healthy rabbits was randomly implanted with diverse wooden foreign bodies (diameter φ = 0.2 mm). The T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), proton density-weighted imaging (PDWI), and susceptibility-weighted imaging (SWI) sequences were applied individually 2 weeks after the implantation. Results IOFBs were detected as linear low signals on T1WI, T2WI, PDWI, and SWI (SWI image). The detectable rates of poplar wood with a length of 0.5 mm were 0%, 50%, 0%, and 67% for T1WI, T2WI, PDWI, and SWI, respectively. SWI and T2WI sequences exhibited higher sensitivity than T1WI and PDWI. The detectable rates of the first three SWI sequences (magnitude, phase, and SWI) were all 67%, which was higher than that of the minimum intensity projection sequence (33%). Conclusion MRI is practicable in the diagnosis of wooden IOFBs. SWI and T2WI are optimal for the integrated diagnosis of wooden IOFBs and could be used for diagnosis and immediate treatment.

A wide variety of pathologic processes, both benign and malignant, affect the central airways. These processes may be classified into 4 distinct groups: anatomic variants, lesions that result in focal or diffuse airway narrowing, and those that result in multinodular airway disorder. Key to the accurate assessment of the central airways is meticulous imaging technique, especially the routine acquisition of contiguous high-resolution, 1-mm to 1.5-mm images. These images enable high-definition axial, coronal, and sagittal reconstructions, as well as advanced imaging techniques, including minimum intensity projection images and virtual bronchoscopy. Current indications most commonly include patients presenting with signs and symptoms of possible central airway obstruction, with or without hemoptysis. In addition to diagnosing airway abnormalities, computed tomography (CT) also serves a critical complementary role to current bronchoscopic techniques for both diagnosing and treating airway lesions. Advantages of CT include noninvasive visualization of the extraluminal extent of lesions, as well as visualization of airways distal to central airways obstructions. As discussed and illustrated later, thorough knowledge of current bronchoscopic approaches to central airway disease is essential for optimal correlative CT interpretation.

Molecular markers associated with diseases can be visualized and quantified noninvasively with targeted ultrasound contrast agent (t-UCA) consisting of microbubbles (MBs) that can bind to specific molecular targets. Techniques used for quantifying t-UCA assume that all unbound MBs are taken out of the blood pool few minutes after injection and only MBs bound to the molecular markers remain. However, differences in physiology, diseases, and experimental conditions can increase the longevity of unbound MBs. In such conditions, unbound MBs will falsely be quantified as bound MBs. We have developed a novel technique to distinguish and classify bound from unbound MBs. In the post-processing steps, first, tissue motion was compensated using block-matching (BM) techniques. To preserve only stationary contrast signals, a minimum intensity projection (MinIP) or 20th-percentile intensity projection (PerIP) was applied. The after-flash MinIP or PerIP was subtracted from the before-flash MinIP or PerIP. In this way, tissue artifacts in contrast images were suppressed. In the next step, bound MB candidates were detected. Finally, detected objects were tracked to classify the candidates as unbound or bound MBs based on their displacement. This technique was validated in vitro, followed by two in vivo experiments in mice. Tumors (n = 2) and salivary glands of hypercholesterolemic mice (n = 8) were imaged using a commercially available scanner. Boluses of 100 mu L of a commercially available t-UCA targeted to angiogenesis markers and untargeted control UCA were injected separately. Our results show considerable reduction in misclassification of unbound MBs as bound ones. Using our method, the ratio of bound MBs in salivary gland for images with targeted UCA versus control UCA was improved by up to two times compared with unprocessed images.

We reported the results of post mortem computed tomography of the liver in 27 subjects dead simultaneously during a flood. The aim of our work was to identify the different patterns of post mortem intrahepatic gas distribution and the timing of its appearance. Although post mortem CT is the method of choice for the evaluation of gas distribution, controversies exist about the first site of appearance of intrahepatic gas (portal veins versus hepatic veins) as well as the timing and steps of intrahepatic gas spreading. In each subject we performed thin slice CT scanner (Somatom Definition, Siemens) and post processing of native CT images with Minimum Intensity Projection technique. Our results show that the first site of appearance of intrahepatic gas is portal veins. Gas in hepatic veins was never seen without the presence of the gas in portal vein. Gaseous cysts in hepatic parenchyma represent a further and usually more tardive pattern of intrahepatic gas distribution. In addition, we demonstrated that differences in timing of gas spreading was statistically significative for exclusive presence of portal veins gas before 48h as well as for complete substitution of hepatic parenchyma by cysts 64h after death. In conclusion, our work shows that the CT study of postmortem intrahepatic gas distribution could be a useful complementary tool both in demonstrating the mechanism of intrahepatic gas spreading and in estimating post mortem interval.

Contains fulltext : 173113.pdf (Publisher’s version ) (Closed access) OBJECTIVE: To investigate the effect of dedicated Computer Aided Detection (CAD) software for automated breast ultrasound (ABUS) on the performance of radiologists screening for breast cancer. METHODS: 90 ABUS views of 90 patients were randomly selected from a multi-institutional archive of cases collected between 2010 and 2013. This dataset included normal cases (n=40) with >1year of follow up, benign (n=30) lesions that were either biopsied or remained stable, and malignant lesions (n=20). Six readers evaluated all cases with and without CAD in two sessions. CAD-software included conventional CAD-marks and an intelligent minimum intensity projection of the breast tissue. Readers reported using a likelihood-of-malignancy scale from 0 to 100. Alternative free-response ROC analysis was used to measure the performance. RESULTS: Without CAD, the average area-under-the-curve (AUC) of the readers was 0.77 and significantly improved with CAD to 0.84 (p=0.001). Sensitivity of all readers improved (range 5.2-10.6%) by using CAD but specificity decreased in four out of six readers (range 1.4-5.7%). No significant difference was observed in the AUC between experienced radiologists and residents both with and without CAD. CONCLUSIONS: Dedicated CAD-software for ABUS has the potential to improve the cancer detection rates of radiologists screening for breast cancer.

We present a case of a 10-month-old girl baby with pulmonary artery sling and bridging bronchus demonstrated using multidetector computed tomography with a three-dimensional volume-rendering display and minimum intensity projections. To the best of our knowledge, this method has been helpful not only in the diagnosis and surgical planning for this rare abnormality but also in the evaluation of prognosis. After pulmonary artery reimplantation, the patient was well and discharged.

Background and purpose The susceptibility-weighted imaging form of brain MRI using minimum intensity projection (mIP) is useful for assessing traumatic brain injuries because it readily reveals deoxyhemoglobin or paramagnetic compounds. We investigated the efficacy of using this methodology in nontraumatic patients. Methods We retrospectively analyzed the asymmetric mIP findings in nontraumatic patients. Asymmetric mIP images were first verified visually and then using ImageJ software. We enrolled patients with a difference of >5% between hemispheres in ImageJ analysis. All patients underwent detailed history-taking and EEG, and asymmetric mIP findings were compared. Results The visual analysis identified 54 pediatric patients (37 males and 17 females) with asymmetric mIP findings. Ten patients were excluded because they did not meet the ImageJ verification criteria. The 44 patients with asymmetry comprised 36 with epilepsy, 6 with headache, and 2 with cerebral infarction. Thirty-one of the 36 epileptic patients showed definite partial seizure activities in semiology, while the remaining patients did not demonstrate a history of partial seizure manifestations. The MRI findings were normal in all patients except for five with periventricular leukomalacia unrelated to seizure symptoms. There was agreement between mIP images and semiology in 29 (93.5%) of the 31 epileptic patients with focal signs, while the other 2 demonstrated discordance. Twenty (64.5%) of the 31 patients showed consistent EEG abnormalities. Conclusions Our data suggest that asymmetric mIP findings are an excellent lateralizing indicator in pediatric patients with partial epilepsy.

A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further 'Gold Standard' method for in-depth morphological study of complex root canal systems.

Minimum intensity projection is a technique commonly used to display magnetic resonance susceptibility weighted images, allowing the observer to better visualize hemorrhages and vasculature. The technique displays the minimum intensity in a given projection within a thick slab, allowing different connectivity patterns to be easily revealed. Unfortunately, the low signal intensity of the skull within the thick slab can mask superficial tissues near the skull base and other regions. Because superficial microhemorrhages are a common feature of traumatic brain injury, this effect limits the ability to proper diagnose and follow up patients. In order to overcome this limitation, we developed a method to allow minimum intensity projection to properly display superficial tissues adjacent to the skull. Our approach is based on two brain masks, the largest of which includes extracerebral voxels. The analysis of the rind within both masks containing the actual brain boundary allows reclassification of those voxels initially missed in the smaller mask. Morphological operations are applied to guarantee accuracy and topological correctness, and the mean intensity within the mask is assigned to all outer voxels. This prevents bone from dominating superficial regions in the projection, enabling superior visualization of cortical hemorrhages and vessels.

Introduction/purpose In vivo detection of cerebral microbleeds (CMBs) from T2* gradient recalled echo (GRE) magnitude image suffers from low specificity, modest inter-rater reproducibility and is biased by its sensitivity to acquisition parameters. New methods were proposed for improving this identification, but they mostly rely on 3D acquisitions, not always feasible in clinical practice. A fast 2D phase processing technique for computing internal field maps (IFM) has been shown to make it possible to characterize CMBs through their magnetic signature in routine clinical setting, based on 2D multi-slice acquisitions. However, its clinical interest for CMBs identification with respect to more common images remained to be assessed. To do so, systematic experiments were undertaken to compare the ratings obtained by trained observers with several image types, T2* magnitude, Susceptibility Weighted Imaging reconstructions (SWI) and IFM built from the same T2*-weighted acquisition. Materials/methods 15 participants from the MEMENTO multi-center cohort were selected: six subjects with numerous CMBs (20 ± 6 CMBs), five subjects with a few CMBs (2 ± 1 CMBs) and four subjects without CMB. 2D multi-slice T2* GRE sequences were acquired on Philips and Siemens 3T systems. After pilot experiments, T2* magnitude, Susceptibility Weighted Imaging (SWI) minimum intensity projection (mIP) on three slices and IFM were considered for the rating experiments. A graphical user interface (GUI) was designed in order to consistently display images in random order. Six raters of various background and expertise independently selected “definite” or “possible” CMBs. Rating results were compared with respect to a specific consensus reference, on both lesion and subject type points of view. Results IFM yielded increased sensitivity and decreased false positives rate (FPR) for CMBs identification compared to T2* magnitude and SWI-mIP images. Inter-rater variability was decreased with IFM when identifying subjects with numerous lesions, with only a limited increase in rating time. IFM thus appears as an interesting candidate to improve CMBs identification in clinical setting., Highlights • We introduce an evaluation of phase-contrast for CMBs detection in clinical setting. • Comparison included T2* magnitude, SWI-mIP and IFM images using a specific GUI. • Rating results showed an improved sensitivity of IFM compared to T2*and SWI-mIP. • A decreased false positive rate with IFM with respect to T2*and SWI-mIP was proved. • We demonstrate a decreased inter-rater variability with IFM.

Objective This micro-computed tomography (MCT) study investigated the utility of thin-slab minimum-intensity projection (TS-MinIP) technique as an adjunct to 3-dimensional (3D) modeling for in-depth morphology study. Study design One hundred one extracted maxillary first molars were scanned for microtomographic analysis (SkyScan). Two-dimensional TS-MinIP and 3D images of mesiobuccal (MB) roots were produced and analyzed to record the number and configurations of the canals, the incidence and location of accessory canals, loop, and intercanal connections, and number of foramina. Results Multiple-canal MB roots were present in 76.2%, and all of the roots had intercanal communications. Weine type III configuration was the most common in the multiple-canal roots. Accessory canals were found in 78.2% of the roots. Configurations that were nonclassifiable were found in 10.9% of the MB roots. Conclusions MB root canal anatomy was complex, and MinIP may serve as an adjunct to 3D modeling for in-depth morphology study.

Summary The objective of this pictorial essay is to highlight the key role of computed tomography scanning (CT scan), particularly minimum intensity projection (MinIP) reformation, with regards to the diagnosis of hypersensitivity pneumonitis (HP) and its contribution to patients’ management. MinIP enhances detecting the characteristic CT scan features of HP, particularly air trapping and ground-glass opacities, features representing the bronchoalveolar lavage or biopsy core target zones to the clinician.

BACKGROUND AND PURPOSE: The detection of microbleeds differs strongly between studies, due to differences in scan protocol. This study aims to compare the visualization of microbleeds with 3D T2*-weighted imaging at 1.5T with 3D dual-echo T2*-weighted imaging at 7T. MATERIALS AND METHODS: Thirty-four patients (29 male; mean age, 58 ± 12 years) with atherosclerotic disease from the Second Manifestations of ARTerial Disease study were included. 3D T2*-weighted imaging at 1.5T and dual-echo T2*-weighted imaging at 7T were done in all patients. The presence and number of definite microbleeds were recorded on minimal intensity projections. Inter- and intraobserver reliability was assessed with Cohen κ test and the ICC. The difference in presence and number of microbleeds was tested with the McNemar test and Wilcoxon signed rank test. RESULTS: The interobserver ICC at 7T was 0.61 and the intraobserver ICC was 0.94, whereas at 1.5T the interobserver ICC was 0.50 and the intraobserver ICC was 0.59. Microbleeds were detected in significantly more patients on 7T (50%) than on 1.5T scans (21%) ( P = .001). The number of microbleeds was also higher at 7T (median, 0.5; range, 0–5) than on 1.5T (median, 0.0; range, 0–6) ( P = .002). CONCLUSIONS: 3D dual-echo T2*-weighted imaging at 7T results in better and more reliable detection of microbleeds compared with 3D T2*-weighted imaging at 1.5T. GRE : gradient recalled-echo ICC : intraclass correlation coefficient MARS : Microbleed Anatomical Rating Scale MIP : minimum intensity projection PRESTO : principles of echo shifting with a train of observations SMART : Second Manifestations of ARTerial disease SNR : signal-to-noise ratio SWI : susceptibility-weighted imaging TE1 : first echo TE2 : second echo

Purpose : The purpose of this study was to evaluate the usefulness of thick slab minimum intensity projection (MinIP) as a follow-up method in patients with pulmonary emphysema. This method was used to determine the presence or absence of changes over time in the lung field based on multi-detector-row CT (MDCT) data. Methods : Among pa- tients diagnosed with pulmonary emphysema who underwent 16-MDCT (slice thickness, 1 mm) twice at an interval of 6 months or more, 12 patients without changes in the lung field and 14 with clear changes in the lung field were selected as subjects. An image in- terpretation experiment was performed by five image interpreters. Pulmonary emphy- sema was followed up using two types of thick slab MinIP (thick slab MinIP 1 and 2) and multi-planar reformation (MPR), and the results of image interpretation were evaluated by receiver operating characteristic (ROC) analysis. In addition, the time required for image interpretation was compared among the three follow-up methods. Results : The area under the ROC curve (Az) was 0.794 for thick slab MinIP 1, 0.778 for the thick slab MinIP 2, and 0.759 for MPR, showing no significant differences among the three meth- ods. Individual differences in each item were significantly more marked for MPR than for thick slab MinIP. The time required for image interpretation was around 18 seconds for thick slab MinIP 1, 11 seconds for thick slab MinIP 2, and approximately 127 seconds for MPR, showing significant differences among the three methods. Conclusion : There were no significant differences in the results of image interpretation regarding the pres- ence or absence of changes in the lung fields between thick slab MinIP and MPR. How- ever, thick slab MinIP showed a shorter image interpretation time and smaller individual differences in the results among image interpreters than MPR, suggesting the usefulness of this method for determining the presence or absence of changes with time in the lung fields of patients with pulmonary emphysema. J. Med. Invest. 58 : 175-179, August, 2011