Vascular Maps Research Articles

Blood Supply in Melanoma Xenografts Is Governed by the Morphology of the Supplying Arteries

Tumor blood supply was related to the morphology of the tumor microvasculature and the supplying arteries (SAs) of A-07-GFP and D-12-GFP melanoma xenografts growing in window chamber preparations in BALB/c nu/nu mice. Blood supply and morphologic parameters were determined from first-pass imaging movies and vascular maps recorded after a bolus of 155-kDa tetramethylrhodamine isothiocyanate–labeled dextran had been administered in-travenously. Poorly supplied tumors showed microvascular networks that did not differ from those of well-supplied tumors in vessel tortuosity, diameter, and density. Conversely, the SAs of poorly supplied tumors were more tortuous and had a smaller diameter than those of well-supplied tumors, resulting in lower plasma velocities in the downstream tumor vessels. Consequently, the blood supply of A-07-GFP and D-12-GFP tumors was governed by the geometric resistance of the SAs rather than by the geometric resistance or the vessel density of the tumor microvasculature. The present study suggests that the SAs may represent an important target for physiological interventions of tumors and that it may be beneficial to focus on the tumor SAs rather than the tumor microvasculature when searching for novel therapeutic strategies for modifying tumor blood supply.

The Pervasive Presence of Fluctuating Oxygenation in Tumors

Tumor hypoxia is a persistent obstacle for traditional therapies in solid tumors. Strategies for mitigating the effects of hypoxic tumor cells have been developed under the assumption that chronically hypoxic tumor cells were the central cause of treatment resistance. In this study, we show that instabilities in tumor oxygenation are a prevalent characteristic of three tumor lines and previous characterization of tumor hypoxia as being primarily diffusion-limited does not accurately portray the tumor microenvironment. Phosphorescence lifetime imaging was used to measure fluctuations in vascular pO(2) in rat fibrosarcomas, 9L gliomas, and R3230 mammary adenocarcinomas grown in dorsal skin-fold window chambers (n = 6 for each tumor type) and imaged every 2.5 minutes for a duration of 60 to 90 minutes. O(2) delivery to tumors is constantly changing in all tumors, resulting in continuous reoxygenation events throughout the tumor. Vascular pO(2) maps show significant spatial heterogeneity at each time point, as well as between time points. The fluctuations in oxygenation occur with a common periodicity within and between tumors, suggesting a common mechanism, but have tumor type-dependent spatial patterns. The widespread presence of fluctuations in tumor oxygenation has broad ranging implications for tumor progression, stress response, and signal transduction, which are altered by oxygenation/reoxygenation events.

Vascular Maps on Contrast-enhanced Breast MR Images: A New Approach Requiring Further Investigation

Vascular Maps on Contrast-enhanced Breast MR Images: A New Approach Requiring Further Investigation

The Cortical Involvement of Territorial Infarcts as a Risk Factor for Stroke-Related Seizures

Background: The cortical involvement of territorial infarcts is considered to be a significant risk factor for the development of early- as well as late-onset seizures. However, it is not known which cortical regions are more susceptible to the development of stroke-related seizures. Patients and Methods: In this retrospective study of 687 patients with territorial infarcts, 184 with stroke-related seizures were compared to 503 without seizures. The extent and the location of the infarcts were determined by computed tomography (CT) scans and/or magnetic resonance imaging (MRI) scans of the brain. The infarcts of the seizure and the non-seizure group were compared on digital cerebral vascular maps by superimposing the CT and/or MRI slices. Results: In patients with late-onset seizures, the infarcts were significantly more frequent in the temporal and parietal branches of the middle cerebral artery in comparison to the non-seizure group. In patients with early-onset seizures and in those with seizures due to a recurrent stroke, the territory of the temporal and occipital branches of the middle cerebral artery was the predilection side of the infarcts. Generalized tonic-clonic seizures occurred mainly in cases of infarction in the deep territory of the middle cerebral and of the anterior choroidal artery. Status epilepticus was significantly correlated with infarcts in the posterior temporal region. Conclusion: Some infarct regions are the sides of predilection for stroke-related seizures according to their type and their onset-time.

Breast vascular mapping obtained with contrast-enhanced MR imaging: implications for cancer diagnosis, treatment, and risk stratification

The value of breast vascular maps obtained using contrast-enhanced MR imaging has recently been explored. Additional information is obtained only by evaluating maximum intensity projections of the first dynamic subtraction to achieve a form of MR angiography of the breast. No increase in acquisition time and no dedicated contrast injections are needed. Four studies have been performed to evaluate the one-sided (asymmetric) increase in vascularity associated with ipsilateral cancer in a total of 404 patients with a cancer prevalence ranging from 38% to 80%. Sensitivity ranged from 72% to 88%, specificity from 57% to 100%, positive predictive value from 85% to 100%, negative predictive value from 38% to 88%, and overall accuracy from 73% to 87%. An asymmetric increase in breast vascularity ipsilateral to a cancer may be due to reduced flow resistance in the tumour, to a high metabolic rate (more likely in large tumours) or to angiogenic stimulation of the whole breast harbouring the lesion (more likely in small tumours). Tumour size could play a specific role in determining the ipsilaterally increased vascularity, and invasive cancers might be more frequently associated with ipsilaterally increased vascularity than in situ cancers. Moreover, while a reduction in breast vasculature has anecdotically been observed in breasts with locally advanced cancers treated with neoadjuvant chemotherapy, especially when taxanes are used, the higher incidence of breast cancer in patients with size asymmetry between the breasts as determined on screening mammography suggests that a role for breast MR vascular mapping in breast cancer risk stratification should be explored. Finally, arteries and veins might be differentiated with dedicated techniques. High-relaxivity agents may be used with advantage in these future investigations.

Contrast-enhanced 3.0-T breast MRI for characterization of breast lesions: increased specificity by using vascular maps

To assess the diagnostic accuracy of contrast-enhanced 3.0-T breast magnetic resonance imaging (MRI) for differentiating benign from malignant breast masses and subsequently to test if specificity could be further improved by scoring of the overall ipsilateral breast vascularity. Fifty-four patients were prospectively enrolled in the study and underwent contrast-enhanced 3.0-T breast MRI. MR images were evaluated and classified according to the MRI BI-RADS lexicon criteria. Lesion size, number of lesions, and localization in the breast were systematically assessed. Maximum intensity projections (MIPS) were obtained by using high-resolution contrast-enhanced (0.1 mmol/kg gadobutrol) fat-saturated T1-weighted images. Breast vascularization was scored according to the methods from Sardanelli et al. by measuring the number, diameter, and length of the vessels on the MIPS. The score ranged from 0 (indicating absent or low breast vascularity) to 3 (indicating high breast vascularity). Final analysis of 56 lesions revealed 25 (45%) malignant lesions and 31 (55%) benign lesions. Correlation with the MRI BI-RADS classification revealed cancer in none (0%) of the BI-RADS II lesions, in 1 (12%) of the BI-RADS III lesions, in 5 (83%) of the BI-RADS IV lesions, and in 19 (100%) of the BI-RADS V lesions. Based on morphologic and kinetic data analysis, the sensitivity and specificity of 3.0-T breast MRI was 100% (25/25) and 74% (23/31), respectively. After adjustment for the breast vascularity score, specificity significantly (p = 0.048) increased to 87% (27/31) without affecting sensitivity. Diagnostic accuracy of contrast-enhanced 3.0-T breast MRI increased significantly when the vascularity score was added to the standard morphologic and kinetic data analysis, resulting in a specificity of 87% without affecting sensitivity, which remained 100%.

Noninvasive Vascular Elastography: Toward A Complementary Characterization Tool of Atherosclerosis in Carotid Arteries

Only a minority of patients with carotid arterial disease have warning symptoms, because the majority of strokes are caused by previously asymptomatic lesions. Because morbidity and mortality after acute stroke are high, patients should be diagnosed and treated before symptoms develop. The hypothesis of this study is that vascular elasticity maps (or elastograms) of carotids are of predictive value for plaque characterization. The strain tensor from either cross-sectional or longitudinal ultrasound radiofrequency data were assessed by a new implementation of the Lagrangian speckle model estimator (LSME), which considers local echogenicity variations. A 26-year-old healthy male (HS1), a 40-year-old (HS2) normal female subject and two 75-year-old asymptomatic patients with severe carotid stenoses were scanned. Reproducible elastograms were obtained as a function of time over five to seven cardiac cycles. Stress-strain modulus elastograms were computed for normal subjects. Stiffening of healthy carotid walls was estimated to be 148 ± 7 kPa and 163 ± 30 kPa at peak-systole for HS1 and HS2, respectively. For patients with heterogeneous plaques, strain and shear elastograms revealed interesting information about plaque size, tissue composition and mechanical interaction between structures. In conclusion, the LSME provides a promising approach for strain and shear estimates to characterize vulnerable plaque. (E-mail: guy.cloutier@umontreal.ca)

Comprehensive esophageal microscopy by using optical frequency–domain imaging (with video)

Optical coherence tomography (OCT) has been used for high-resolution endoscopic imaging and diagnosis of specialized intestinal metaplasia, dysplasia, and intramucosal carcinoma of the esophagus. However, the relatively slow image-acquisition rate of the present OCT systems inhibits wide-field imaging and limits the clinical utility of OCT for diagnostic imaging in patients with Barrett's esophagus. This study describes a new optical imaging technology, optical frequency-domain imaging (OFDI), derived from OCT, that enables comprehensive imaging of large esophageal segments with microscopic resolution. A prototype OFDI system was developed for endoscopic imaging. The system was used in combination with a balloon-centering catheter to comprehensively image the distal esophagus in swine. Volumetric images of the mucosa and portions of the muscularis propria were obtained for 4.5-cm-long segments. Image resolution was 7 microm in depth and 30 microm parallel to the lumen, and provided clear delineation of each mucosal layer. The 3-dimensional data sets were used to create cross-sectional microscopic images, as well as vascular maps of the esophagus. Submucosal vessels and capillaries were visualized by using Doppler-flow processing. Comprehensive microscopic imaging of the distal esophagus in vivo by using OFDI is feasible. The unique capabilities of this technology for obtaining detailed information of tissue microstructure over large mucosal areas may open up new possibilities for improving the management of patients with Barrett's esophagus.

Computed tomographic changes of the brain and clinical outcome of patients with seizures and epilepsy after an ischaemic hemispheric stroke

It is not well established whether seizures and epilepsy after an ischaemic stroke increase the disability of patients. Seventy-two patients with delayed seizures after a hemispheric infarct (37 with a single seizure and 35 with epilepsy) were included in the study. The modified Rankin scale was used to compare disability of the patients at 1 month after stroke and at 2 weeks after single or the last seizure, in case of epilepsy. The size of the X-ray hypoattenuation zone was compared on computed tomographic (CT) scans, performed in the weeks after the stroke and 1 week after single or repeated seizures. Lesion size was determined by superimposing the CT slices on digital cerebral vascular maps, on which the contours of the infarct area were delineated. The extent of the infarcts was expressed as the percentage fraction of the total surface area of the cerebral hemisphere. Groups with a single seizure and with epilepsy were mutually compared. Infarcts predominated in the parieto-temporal cortical regions. In the overall group the median Rankin score worsened significantly after seizures. The average size of the X-ray hypoattenuation zone was also significantly increased on the CT scans after the seizures, compared with those after stroke, without clear evidence of recent infarction. Mutual comparison of patients with a single seizure episode and of those with epilepsy showed only a trend of more severe disability and of increase in lesion size in the post-stroke epilepsy group. Delayed seizures and epilepsy after ischaemic stroke are accompanied by an increase in lesion size on CT and by worsening of the disability of the patients. This study does not allow to determine whether this is due to stroke recurrence or due to additional damage as a result of the seizures themselves.

Vascular Mapping of the Leg with Multi–Detector Row CT Angiography prior to Free-Flap Transplantation

To retrospectively evaluate multi-detector row computed tomographic (CT) angiography in determining donor- and recipient-site arterial suitability for successful vascularized free-flap transplantation. The institutional review board granted approval; informed consent was waived, and the study was HIPAA compliant. Lower extremities of 20 (12 male, eight female; mean age, 51 years; range, 10-84 years) patients undergoing vascularized free-flap procedures were examined at multi-detector row CT angiography. In five patients, legs were assessed as potential fibular free-flap donors for mandibular, maxillary, or radial reconstruction. In 15 patients, legs were assessed as recipient sites for free flaps. Vascular maps obtained with volume rendering, maximum intensity projections, and curved planar reformations were generated, and assessment was made in the depiction of calf vessels and presence of stenosis, occlusion, and anatomic anomaly. Findings of CT angiography, physical examination, and surgery were compared, where applicable, and successful CT-based prediction of the surgical intervention was assessed. Immediate and long-term (>70 days) viability of the graft was assessed in all patients. CT angiography depicted the entirety of all four major calf arteries in 29 of 32 legs scanned. In three legs, external-fixation hardware obscured some segments. There were no discrepancies between CT findings and those identified at the time of surgery. Arterial abnormalities, including stenosis, occlusion, and variant anatomy, were seen in 12 lower extremities in 10 patients. Only two were suspected on the basis of physical examination findings. In five of 20 patients, CT findings resulted in changes to the surgical plan. There was a 100% immediate viability of all grafts, which remained well vascularized between 70 days and 37 months after the procedure. Multi-detector row CT angiography provides a noninvasive means of preoperatively assessing lower extremity arteries for abnormalities, which could jeopardize graft viability or pedal arterial supply after free-flap procedures.

Defining Vascular Supply and Territory of Thinned Perforator Flaps: Part I. Anterolateral Thigh Perforator Flap

The anterolateral thigh perforator flap is increasingly being used for trauma and reconstructive surgical cases. With the thinned flap design, greater survivability and a decrease in donor-site morbidity are observed. To increase our knowledge of the vascular territories in these flaps, an anatomic study was performed to determine pedicle number, location, and diameter; accompanying veins; vascular territory; and where surgical incisions can be made safely during thinning, as opposed to the "danger zone." Thirteen anterolateral thigh perforator flaps were harvested from seven adult cadavers. The largest perforator arteries were cannulated, and flaps were thinned to a thickness of 6 to 8 mm, with a 2.5-cm radius from the perforator retained. Vascular territories were quantified before and after thinning by nonradiographic and radiographic methods. A series of dyes were injected: red dye for skin (photography) followed by Omnipaque for the whole flap (radiography) before thinning, and blue dye for skin (photography) and lead oxide for the whole flap (radiography) after thinning. Pedicle locations were determined by ratios of anatomical landmarks. Danger zone measurements were derived at specific thicknesses using lateral radiographs of each flap. In anterolateral thigh perforator flaps, the mean perforator artery diameter at the fascia level was 1.00 +/- 0.08 mm (range, 0.84 to 1.11 mm) and the mean number of perforator arteries was 1.69 +/- 1.03 (+/-SD). Perforator pedicles were located near the midpoint of the line between the anterior superior iliac spine and the lateral aspect of the patella in the vertical axis. The mean vascular territories were 256 +/- 52.5 cm2 (photography) and 351 +/- 72.8 cm2 (radiography) in unthinned flaps and 211 +/- 65.7 cm2 (photography) and 289 +/- 106.6 cm2 (radiography) in thinned flaps. Differences in overall vascular territories after thinning were 83.3 percent (photography) and 81.8 percent (radiography) compared with unthinned flaps. Four respective vascular territory maps were drawn showing surgical territories using percentile confidence intervals (98th and 90th) and averages. From the skin at thicknesses of 4, 6, and 8 mm, the 98th percentile danger zones were 33 to 37 mm (proximal to distal), 30 to 35 mm, and 27 to 31 mm from the pedicle in the vertical axis, respectively; in the horizontal axis, they were 30 to 34 mm (medial to lateral), 28 to 31 mm, and 25 to 29 mm. These data define anterolateral thigh perforator flap pedicle location, number, and diameter before harvesting, surgical danger zones during thinning, and vascular territories after thinning. The authors' guidelines provide surgeons with anatomical vascular territory maps to design and harvest specific flaps for optimal results.

Will Improved Vascular Mapping Achieved with Gadobenate Dimeglumine Aid in Interpretation of Breast MR Images?

HomeRadiologyVol. 235, No. 3 Next Science to PracticeWill Improved Vascular Mapping Achieved with Gadobenate Dimeglumine Aid in Interpretation of Breast MR Images?Liane E. PhilpottsLiane E. PhilpottsAuthor Affiliations1Department of Radiology, Yale University School of Medicine, 333 Cedar St, PO Box 208042, New Haven, CT 06520-8042 [email protected]Liane E. PhilpottsPublished Online:Jun 1 2005https://doi.org/10.1148/radiol.2353042165MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References 1 Sardanelli F, Iozzelli A, Fausto A, Carriero A, Kirchin M. Gadobenate dimeglumine–enhanced MR imaging breast vascular maps: association between invasive cancer and ipsilateral increased vascularity. Radiology 2005; 235:791-797. Link, Google Scholar2 Kirchin MA, Pirovano G, Venetianer C, Spinazzi A. Safety assessment of gadobenate dimeglumine (MultiHance): extended clinical experience from phase I studies to post-marketing surveillance. J Magn Reson Imaging 2001; 14:281-294. Crossref, Medline, Google ScholarArticle HistoryPublished in print: June 2005 FiguresReferencesRelatedDetailsCited ByContrast-enhanced breast MR imaging of claustrophobic or oversized patients using an open low-field magnetM.Calabrese, D.Brizzi, L.Carbonaro, M.Chiaramondia, M.A.Kirchin, F.Sardanelli2009 | La radiologia medica, Vol. 114, No. 2The Challenge of Imaging Dense Breast ParenchymaFedericaPediconi, CarloCatalano, AntonellaRoselli, ValeriaDominelli, SabrinaCagioli, AngelikiKaratasiou, AnnaMariaPronio, Miles A.Kirchin, RobertoPassariello2009 | Investigative Radiology, Vol. 44, No. 7Vascular Maps on Contrast-enhanced Breast MR Images: A New Approach Requiring Further InvestigationFrancesco Sardanelli, 1 April 2008 | Radiology, Vol. 247, No. 1Contrast-enhanced MR Mammography for Evaluation of the Contralateral Breast in Patients with Diagnosed Unilateral Breast Cancer or High-Risk Lesions1Federica Pediconi, , Carlo Catalano, , Antonella Roselli, , Simona Padula, , Fiorella Altomari, , Enrica Moriconi, , Anna Maria Pronio, , Miles A. Kirchin, , and Roberto Passariello, 1 June 2007 | Radiology, Vol. 243, No. 3Contrast-enhanced magnetic resonance mammography: does it affect surgical decision-making in patients with breast cancer?FedericaPediconi, CarloCatalano, SimonaPadula, AntonellaRoselli, EnricaMoriconi, ValeriaDominelli, Anna MariaPronio, Miles A.Kirchin, RobertoPassariello2007 | Breast Cancer Research and Treatment, Vol. 106, No. 1Recommended Articles Performance of Screening Breast MRI across Women with Different Elevated Breast Cancer Risk IndicationsRadiology2019Volume: 292Issue: 1pp. 51-59Dentate Nucleus Signal Intensity Increases Following Repeated Gadobenate Dimeglumine Administrations: A Retrospective AnalysisRadiology2020Volume: 296Issue: 1pp. 122-130Impact of Preoperative Breast MR Imaging and MR-guided Surgery on Diagnosis and Surgical Outcome of Women with Invasive Breast Cancer with and without DCIS ComponentRadiology2017Volume: 284Issue: 3pp. 645-655The Value of Patient and Tumor Factors in Predicting Preoperative Breast MRI OutcomesRadiology: Imaging Cancer2020Volume: 2Issue: 4Delayed Gadolinium-enhanced MR Imaging of Cartilage: A Comparative Analysis of Different Gadolinium-based Contrast Agents in an ex Vivo Porcine ModelRadiology2016Volume: 282Issue: 3pp. 734-742See More RSNA Education Exhibits Abbreviated Breast MRI: Past, Present, and FutureDigital Posters2019Malignant Papillary Tumors of the Breast: Radiologist’s Role for a Complete Diagnostic AssessmentDigital Posters2019Everything but BRCA: Imaging Hereditary Breast Cancer GenesDigital Posters2019 RSNA Case Collection Breast Papillomatosis with DCISRSNA Case Collection2020Invasive Papillary CarcinomaRSNA Case Collection2020Multifocal breast cancerRSNA Case Collection2020 Vol. 235, No. 3 Metrics Altmetric Score PDF download

Gadobenate Dimeglumine–enhanced MR Imaging Breast Vascular Maps: Association between Invasive Cancer and Ipsilateral Increased Vascularity

To retrospectively compare three different doses of gadobenate dimeglumine with a standard dose of gadopentetate dimeglumine for magnetic resonance (MR) imaging evaluation of breast vessels and to evaluate the accuracy of one-sided increased vascularity seen on gadobenate dimeglumine-enhanced MR images as an indicator of ipsilateral breast cancer. The original study had local ethics committee approval; informed consent was obtained from all enrolled patients. Ninety-five patients known to have or suspected of having breast cancer were randomly assigned to four groups to receive gadobenate dimeglumine at a dose of 0.05, 0.10, or 0.20 mmol per kilogram of body weight or gadopentetate dimeglumine at a dose of 0.10 mmol/kg. T1-weighted gradient-echo MR images were acquired before and 2 minutes after intravenous contrast material injection. Subtracted images were used to obtain maximum intensity projections (MIPs). Two readers blinded to the type and dose of contrast agent administered scored the MIPs obtained in the dose groups for vessel number, length, and conspicuity from 0, which indicated absent or low breast vascularity, to 3, which indicated high breast vascularity. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of one-sided increased vascularity in association with ipsilateral malignancy for 69 histopathologically confirmed lesions (reference standard) were determined after gadobenate dimeglumine-enhanced MR imaging. The mean MIP scores assigned to the gadobenate dimeglumine groups were significantly higher than those assigned to the gadopentetate dimeglumine group (P < or = .044). Histopathologic analysis revealed malignant lesions in 52 of 69 patients examined with gadobenate dimeglumine MR imaging: invasive ductal carcinoma in 45, invasive lobular carcinoma in four, and invasive mixed ductal-lobular carcinoma in three patients. Seventeen patients had benign lesions. Two cases of bilateral invasive cancer with symmetric breast vascular maps were excluded. Thus, the overall sensitivity, specificity, accuracy, PPV, and NPV of one-sided increased vascularity as a finding associated with ipsilateral malignancy were 88% (44 of 50 patients), 82% (14 of 17 patients), 87% (58 of 67 patients), 94% (44 of 47 patients), and 70% (14 of 20 patients), respectively. Gadobenate dimeglumine is effective for MR imaging evaluation of breast vessels at doses as low as 0.05 mmol/kg. One-sided increased vascularity is an MR imaging finding frequently associated with ipsilateral invasive breast cancer.

A method for the analysis of the geometrical relationship between white matter pathology and the vascular architecture of the brain

A novel method for the visual and quantitative analysis of the geometrical relationship between the vascular architecture of the brain and white matter pathology is presented. The cerebro vascular system is implicated in the pathogenesis of many diseases of the cerebral white matter, for example, stroke, microcerebrovascular disease, and multiple sclerosis (MS). In our work, white matter lesions and vessels are depicted using magnetic resonance imaging (MRI) and extracted using image analysis techniques. We focus on measuring distance relationships between white matter lesions and vessels, and distribution of lesions with respect to vessel caliber. Vascular distance maps are generated by computing for each voxel the Euclidean distance to the closest vessel. Analogously, radius maps assign the radius of the closest vessel to each voxel in the image volume. The distance and radius maps are used to analyze the distribution of lesions with respect to the vessels' locations and their calibers. The method was applied to three MS patients to demonstrate its functionality and feasibility. Preliminary findings indicate that larger MS lesions tend to be farther from detected vessels and that the caliber of the vessels nearest to larger lesions tends to be smaller, suggesting a possible role of relative hypoperfusion or hypoxia in lesion formation.

The Prognostic Significance of Changes in Lesion Size of Established Cerebral Infarcts on Computed Tomography of the Brain

Background: As a second part of our prospective study, we assessed the size of the infarct lesion on computed tomography (CT) of the brain at two fixed time points after stroke in order to investigate its influence on the clinical outcome. Methods: From 220 consecutive stroke patients, admitted within 24 h after onset with symptoms lasting more than 24 h, we selected 150 displaying an anterior circulation infarct or syndrome. All included patients had CT scans without contrast enhancement on day 3 (± 8 h) and on day 10 (± 8 h) after stroke onset. The size of the X-ray hypoattenuation zone was determined by superimposing the CT slices on digital cerebral vascular maps, on which the contours of the infarct area were delineated. The lesion size was expressed as the fraction of the total surface area of these digital cerebral maps. The patients were divided into four groups according to their degree of disability at 3 months on the modified Rankin (R) scale as follows : R 0–1, R 2–3, R 4–5, R 6. Results: There was a clear association between lesion size on CT, on day 3 and on day 10, and the clinical outcome. Lesion size decreased between day 3 and day 10 in the groups R 0–1 and R 2–3, remained unchanged in the group R 4–5 and further increased in group R 6. Conclusion: Lesion size on CT is a significant predictor of stroke outcome. It decreases from day 3 to day 10 in patients with no or low disability at 3 months, but increases in those who do not survive their stroke.

Three-dimensional Multi–Detector Row CT Portal Venography in the Evaluation of Portosystemic Collateral Vessels in Liver Cirrhosis

Multi-detector row computed tomography (CT) offers distinct advantages over traditional spiral CT. Multi-detector row CT scanners are faster and allow thinner collimation than single-detector row spiral CT scanners. The use of multi-detector row CT combined with postprocessing of the imaging data with a variety of three-dimensional reformatting techniques (eg, maximum intensity projection, shaded surface display, volume rendering) allows creation of vascular maps whose quality equals or exceeds that of maps created at classic angiography for many applications. Three-dimensional multi-detector row CT portal venography can help determine the extent and location of portosystemic collateral vessels (eg, left gastric vein, short gastric vein, esophageal and paraesophageal varices, splenorenal and gastrorenal shunts, paraumbilical and abdominal wall veins) in patients with liver cirrhosis and is probably the optimal imaging technique in this setting.

Volume-rendered 3D CT of the mesenteric vasculature: normal anatomy, anatomic variants, and pathologic conditions.

Multi-detector row computed tomography (CT) offers important advantages over more conventional imaging methods in the evaluation of the mesenteric vasculature. It allows faster scanning, which practically eliminates motion and breathing artifacts, as well as thinner collimation. These advances, coupled with rapid intravenous administration of contrast material, allow excellent opacification of the mesenteric arteries and veins. This improves the quality of the three-dimensional (3D) data sets, which in turn leads to improved 3D vascular maps and more accurate assessment of various conditions such as arterial or venous encasement in patients with pancreatic cancer, mesenteric ischemia, or inflammatory bowel disease. Three-dimensional multi-detector row CT also allows better visualization of arterial and venous branching, thereby improving detection of more distal vascular involvement. In addition, 3D multi-detector row CT may help detect hemodynamic changes in patients with active inflammation and hyperemia of a bowel segment because it can be used to measure bowel wall enhancement over time. Carcinoid tumors that have infiltrated the mesentery have a characteristic CT appearance, and other conditions such as lymphoma or sclerosing mesenteritis can also manifest as an infiltrating mass that envelops mesenteric vessels. Three-dimensional multi-detector row CT represents a significant advance in CT technology and can help ensure prompt, accurate evaluation of the mesenteric vasculature.

From the RSNA refresher courses: CT angiography: clinical applications in the abdomen.

The development of spiral computed tomography (CT) and subsequently multidetector CT has provided unparalleled opportunities for advancement of CT technology and clinical applications. One of the most influential developments has been CT angiography, which is the use of thin-section CT combined with postprocessing of imaging data by using a variety of three-dimensional reconstruction techniques to produce vascular maps that equal or exceed those provided by classic angiography in many applications. In the evaluation of pancreatic disease, the use of multidetector CT angiography enables the radiologist to produce vascular maps that clearly show tumor invasion of vasculature and the relationship of vessels to pancreatic masses. Anatomic areas for which the three-dimensional display is especially helpful include the confluence of the portal vein and the superior mesenteric vein and the more distal portions of the portal vein. Preliminary studies indicate that CT angiography may prove beneficial in the evaluation of ischemic bowel and active Crohn disease. CT angiography has proved extremely valuable for applications such as preoperative planning for hepatic resection, preoperative evaluation and planning for liver transplantation, pretreatment planning for patients considered for hepatic arterial infusion chemotherapy, and pretreatment evaluation of portal vein patency for a variety of reasons. CT angiography can also provide supplemental information in patients with cirrhosis, upper gastrointestinal tract bleeding due to varices, or primary extrahepatic neoplasms.

Measurement of tumor vascular volume and mean microvascular random flow velocity magnitude by dynamic Gd-DTPA-albumin enhanced and diffusion-weighted MRI.

Tumor vascular volume fraction and the magnitude of the mean microvascular random flow velocity were measured in an animal tumor model by combining dynamic Gd-DTPA-albumin enhanced MRI and diffusion-weighted MRI in conjunction with a compartmental modeling analysis. The vascular volume fraction maps were obtained from the dynamic Gd-DTPA-albumin enhanced MRI measurement. It was found that the vascular volume fraction for Walker 256 tumor was higher within the outgrowing rim and decreased towards the central region. The average value obtained from five animals was 0.062 +/- 0.009 ml/g. By using the vascular volume fraction from the Gd-DTPA-albumin enhanced MRI measurement, maps of the magnitude of the mean microvascular random flow velocity were obtained from the diffusion-weighted MRI measurements with the compartmental modeling analysis. The relative extravascular and intravascular contributions to the diffusion-weighted MRI signal were determined for three tissue groups with different Gd-DTPA-albumin enhancement characteristics, and the flow and molecular diffusion-induced attenuation factors for the intravascular compartment were also compared. The mean microvascular random flow velocity magnitude maps were obtained with an average value of 0.67 +/- 0.06 mm/s.

Detection, visualization and animation of abnormal anatomic structure with a deformable probabilistic brain atlas based on random vector field transformations

This paper describes the design, implementation and preliminary results of a technique for creating a comprehensive probabilistic atlas of the human brain based on high-dimensional vector field transformations. The goal of the atlas is to detect and quantify distributed patterns of deviation from normal anatomy, in a 3-D brain image from any given subject. The algorithm analyzes a reference population of normal scans and automatically generates color-coded probability maps of the anatomy of new subjects. Given a 3-D brain image of a new subject, the algorithm calculates a set of high-dimensional volumetric maps (with typically 384 2 × 256 × 3 ≈ 10 8 degrees of freedom) elastically deforming this scan into structural correspondence with other scans, selected one by one from an anatomic image database. The family of volumetric warps thus constructed encodes statistical properties and directional biases of local anatomical variation throughout the architecture of the brain. A probability space of random transformations, based on the theory of anisotropic Gaussian random fields, is then developed to reflect the observed variability in stereotaxic space of the points whose correspondences are found by the warping algorithm. A complete system of 384 2 × 256 probability density functions is computed, yielding confidence limits in stereotaxic space for the location of every point represented in the 3-D image lattice of the new subject's brain. Color-coded probability maps are generated, densely defined throughout the anatomy of the new subject. These indicate locally the probability of each anatomic point being unusually situated, given the distributions of corresponding points in the scans of normal subjects. 3-D MRI and high-resolution cryosection volumes are analyzed from subjects with metastatic tumors and Alzheimer's disease. Gradual variations and continuous deformations of the underlying anatomy are simulated and their dynamic effects on regional probability maps are animated in video format (on the accompanying CD-ROM). Applications of the deformable probabilistic atlas include the transfer of multi-subject 3-D functional, vascular and histologic maps onto a single anatomic template, the mapping of 3-D atlases onto the scans of new subjects, and the rapid detection, quantification and mapping of local shape changes in 3-D medical images in disease and during normal or abnormal growth and development.