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ABSTRACT: To assess the impact of cycles of freezing and thawing on magnetic resonance (MR) images (obtained by use of a 3-T magnet) of equine feet examined ex vivo.
9 forelimbs from 9 horse cadavers.
9 forefeet underwent MR imaging first at ambient temperature within 12 hours after the horses' death and then after each freezing-thawing cycle. Three digits underwent freezing and thawing (at 4°C for 36 hours) 2 times, 3 digits underwent freezing and thawing (at 4°C for 36 hours) once and rescanning after 24 hours at ambient temperature, and 3 digits underwent freezing and thawing at ambient temperature for 24 hours once. Images of the digits obtained prior to freezing were subjectively compared with images obtained after freezing and thawing. Changes in the signal-to-noise ratio between examinations were assessed.
Overall image quality was considered unchanged except for the hoof capsule. Quantitative analysis revealed signal-to-noise ratio changes in bone marrow, soft tissues, and hoof capsule induced with both thawing processes. The signal-to-noise ratio in the synovial recess of the distal interphalangeal joint significantly increased as a result of thawing at 4°C.
Although overall image quality was considered unchanged except for the hoof capsule, results suggested that changes induced in cadaver limbs following freezing and thawing, which are probably attributable both to modified and inhomogeneous temperature distribution and direct tissue damage, may alter the reliability of signal intensity in ex vivo MR examinations.
American Journal of Veterinary Research 06/2011; 72(6):780-90. · 1.27 Impact Factor
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ABSTRACT: Venous thromboembolic disease (VTE) is a common disorder which may be associated with high morbidity or mortality when left untreated. Specific VTE diagnosis is mandatory, as treatment is associated with significant side effects. Therefore, timely diagnostic tests are necessary to establish the presence or absence of VTE. Computed tomographic pulmonary angiography (CTPA) has reached a high accuracy in the evaluation of pulmonary embolism (PE). Unfortunately, the continuous decrease of the prevalence of PE in the most recent studies can lead to cost-efficacy imbalance and overuse of ionizing radiation when CTPA is used as a single test. Therefore, no single non-invasive test is suitable for all patients and diagnostic strategies based on sequential non-invasive tests are likely to identify patients in whom anticoagulation can be withheld safely and limit the number of patients requiring more invasive or more expensive tests. The cost effectiveness of clinical stratification and D-dimer test has been demonstrated as it reduces the requirement for invasive tests. In this paper, the current role of CTPA in the diagnosis of PE will be reviewed.
European Radiology 04/2008; 18(3):500-9. · 3.22 Impact Factor
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ABSTRACT: Indirect computed tomography (CT) venography reportedly provides high accuracy for detection of venous thrombosis in patients suspected of pulmonary embolism (PE). Nevertheless, the extent of the scanning range for lower limb and abdominal veins remains to be determined. It was the objective of this study to investigate the distribution of venous thrombosis in order to identify the most appropriate extent of scanning range when using CT venography. We reviewed 1,408 combined CT pulmonary angiographies (CTPA) and indirect CT venographies of the lower limbs, performed in patients suspected of PE. Percentage of venous thromboembolism (VTE), which includes PE and/or venous thrombosis was calculated. Location and the upper end of clots were recorded in 37 venous segments per patient from calf to diaphragm. PE, venous thrombosis and VTE, were found respectively in 272 (19.3%), 259 (18.4%) and 329 (23.4%) patients. Addition of CT venography to CTPA increased depiction of VTE in 17.3%. The upper end of venous thrombosis was located below the knee in 48%, between knee and inguinal ligament in 36% of the patients, and above the inguinal ligament in 15%. Ninety-six patients had thrombosis in a single vein, of which none occurred above the iliac crests in a patient without PE at CTPA. In conclusion, when added to CTPA, optimal scanning of CT venography should extent from calves to the iliac crests in patients suspected of VTE.
Thrombosis and Haemostasis 05/2007; 97(4):566-72. · 5.04 Impact Factor
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American Journal of Roentgenology 10/2006; 187(3):W327-8. · 2.78 Impact Factor
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ABSTRACT: To compare retrospectively the incremental value of indirect computed tomographic (CT) venography performed after multi-detector row CT pulmonary angiography and single-detector row CT pulmonary angiography for the diagnosis of venous thromboembolism (VTE).
The institutional ethics committee approved this study; informed consent was not required. The authors retrospectively reviewed results of 1100 combined single-detector row CT pulmonary angiographic and indirect CT venographic examinations (542 men, 558 women; mean age, 61 years +/- 17 [standard deviation]) (group 1) and 308 combined multi-detector row CT pulmonary angiographic and indirect CT venographic examinations (150 men, 158 women; mean age, 62 years +/- 18) (group 2), performed in 1408 patients suspected of having pulmonary embolism (PE). Frequency of deep venous thrombosis (DVT), PE, and VTE, and the incremental value of indirect CT venography were recorded in both groups. Data were compared by means of the Student t test for continuous data and z statistics for independent proportions.
VTE, PE, and DVT were found in 23.3% (n = 256), 19.9% (n = 219), and 18.3% (n = 201) of the 1100 patients in group 1, respectively, and in 23.7% (n = 73), 17.2% (n = 53), and 18.8% (n = 58) of the 308 patients in group 2, respectively (P values ranging from .273 to .876). The incremental value of indirect CT venography was 14.4% (37 of 256 patients) in group 1 and 27.4% (20 of 73 patients) in group 2.
Despite potential improved accuracy of multi-detector row CT pulmonary angiography for the diagnosis of PE, the addition of indirect CT venography increased the diagnosis of VTE in 27.4% of patients.
Radiology 08/2006; 240(1):256-62. · 5.73 Impact Factor
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Liver Transplantation 06/2006; 12(5):888-9. · 3.39 Impact Factor
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ABSTRACT: To retrospectively evaluate pulmonary artery (PA) clot load scores and computed tomographic (CT) cardiovascular parameters as predictors of mortality in patients with severe pulmonary embolism (PE).
Institutional review board approval was obtained with waiver of informed consent. A total of 82 consecutive patients (42 women, 40 men; mean age+/-standard deviation, 61 years+/-15) were admitted to the intensive care unit for PE-related conditions and were evaluated by using CT pulmonary angiography. Two independent readers who were blinded to clinical outcome quantified PA clot load by using four scoring systems. Cardiovascular measurements included right ventricular (RV) and left ventricular (LV) short-axis measurements; RV short axis to LV short axis (RV/LV) ratios; main PA, ascending aorta, azygos vein, and superior vena cava diameters; and main PA diameter to aorta diameter ratios. Reflux of contrast medium into the inferior vena cava, leftward bowing of the interventricular septum, pleural or pericardial effusion, pulmonary consolidation, infarct, platelike atelectasis, and mosaic ground-glass opacity were also recorded. Results were correlated with patient outcome during hospital stay by using the Wilcoxon rank sum and chi2 tests.
Twelve patients died within 1-14 days. RV and LV short axis; RV/LV ratio; azygos vein, superior vena cava, and aorta diameters; and contrast medium reflux into the inferior vena cava were significantly different between survivors and nonsurvivors (P<.05). No significant relationship was found between PA clot load and mortality rate. RV/LV ratio and azygos vein diameter allowed correct prediction of survival in 89% of patients (P<.001).
RV/LV ratio and azygos vein diameter are predictors of mortality in patients with severe PE.
Radiology 06/2006; 239(3):884-91. · 5.73 Impact Factor
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ABSTRACT: This study evaluated CT findings for signs of blunt diaphragmatic rupture.
CT examinations of 179 blunt trauma patients, including 11 with left-sided and five with right-sided blunt diaphragmatic rupture, were reviewed by two staff radiologists who first decided by consensus on the presence or absence of 11 published signs of blunt diaphragmatic rupture and then formulated the diagnosis in terms of absence of, presence of, or suggestion of blunt diaphragmatic rupture. The significance of the findings was assessed by multivariate logistic regression. Four other reviewers interpreted the CT findings independently. They were asked first to formulate a diagnosis in terms of absence of, presence of, or suggestion of blunt diaphragmatic rupture and then to enumerate the findings supporting a diagnosis or suggestion of blunt diaphragmatic rupture. These findings were compared with those of the staff radiologists.
Diaphragmatic discontinuity, diaphragmatic thickening, segmental nonrecognition of the diaphragm, intrathoracic herniation of abdominal viscera, elevation of the diaphragm, and both hemothorax and hemoperitoneum were strong predictors of blunt diaphragmatic rupture (p < 0.001). The combination of the first three findings was 100% sensitive (16/16). The staff radiologists' sensitivity for diagnosing blunt diaphragmatic rupture was 100% (16/16). The four reviewers' sensitivities were 56.2% (9/16), 81.2% (13/16), 62.5% (10/16), and 87.5% (14/16).
Six of 11 signs were good predictors of blunt diaphragmatic rupture. Despite diaphragmatic thickening, focal defect and segmental nonrecognition had 100% cumulative sensitivity; the reviewers formulating the diagnosis before analyzing CT signs overlooked blunt diaphragmatic rupture on CT in 12.5-43.8% of the patients.
American Journal of Roentgenology 02/2005; 184(1):24-30. · 2.78 Impact Factor
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Plastic & Reconstructive Surgery 07/2004; 113(7):2091-4. · 3.38 Impact Factor
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ABSTRACT: Percutaneous ablation is a well-established technique for treating cardiac arrhythmia by removing or isolating tissue at the site of the abnormal impulse formation. Various forms of energy for ablation procedures may be delivered via a catheter with fluoroscopic guidance. The procedures most commonly performed are radiofrequency ablation and cryotherapy. Atrial fibrillation, the most frequently occurring supraventricular tachyarrhythmia, may be initiated by ectopic beats that originate in the ostia of the pulmonary veins. The clinical efficacy of isolation (or focal ablation) of the pulmonary veins for treatment of atrial fibrillation has been well demonstrated. Pre- and postprocedural examinations with computed tomography (CT) or magnetic resonance (MR) imaging are frequently performed to depict the anatomy and to obtain baseline measurements of the pulmonary veins to enable early detection of complications from ablation. Venous stenosis or thrombosis and pulmonary hypertension may occur after radio-frequency ablation. Familiarity with the appearance of normal anatomic variants at CT and MR imaging and with the normal range of pulmonary vein diameters is essential for preoperative management and early detection of procedure-related complications.
Radiographics 11/2003; 23 Spec No:S19-33; discussion S48-50. · 2.85 Impact Factor
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ABSTRACT: This study was prospectively conducted to assess the feasibility, safety and accuracy of an 8-G directional vacuum-assisted biopsy (DVAB) probe in the diagnostic management of nonpalpable breast lesions (NPBL). Of 170 planned procedures which were indicated for investigation of BI-RADS category-3 to category-5 lesions, 153 were performed in 138 consecutive patients. The probe was targeted by the stereotactic unit of a prone table (United States Surgical Corporation, Norwalk, Conn.; and Lorad, Danbury, Conn.). Four to 18 (mean 8) core specimens were obtained for each lesion. In case of complete removal of the lesion, a localizing clip was deployed at the biopsy site. Adequate material for histopathologic examination was obtained in all cases (100%). Four of 138 (3%) patients experienced mild hematomas. We observed 15 of 39 failures (38%) to place the localizing clips. Thirteen of 153 (8%) procedures were inconclusive and required reintervention. Following DVAB, 42 of 138 (30%) patients underwent surgery. Subject to incomplete follow-up of the entire cohort, we observed no false-positive and one false-negative diagnosis. These preliminary results suggest that DVAB using an 8-G probe are feasible, safe and accurate. In our experience, clip placement was problematic. It is probable that increasing the dimensions of DVAB will only be relevant in a limited number of clinical situations, primarily the desire to obtain complete radiologic resections of the target abnormality.
European Radiology 10/2002; 12(9):2180-7. · 3.22 Impact Factor
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ABSTRACT: Deep venous thrombosis and pulmonary embolism are the two aspects of venous thrombo-embolism. Investigation of lower limb veins has been part of various diagnostic algorithms in the past 15 years. Recently, the combination of CT venography (CTV) of lower limbs and abdominal veins together with CT angiography of the pulmonary arteries has allowed a complete examination of venous thrombo-embolism in one session. The technical aspects, imaging findings, venous anatomy on CT, interpretative pitfalls, results and advantages of CT venography are reviewed.
European Radiology 09/2002; 12(8):1906-21. · 3.22 Impact Factor
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The Lancet 07/2002; 359(9322):1998. · 38.28 Impact Factor
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ABSTRACT: This study was prospectively conducted to assess the feasibility, safety and accuracy of an 8-G directional vacuum-assisted
biopsy (DVAB) probe in the diagnostic management of nonpalpable breast lesions (NPBL). Of 170 planned procedures which were
indicated for investigation of BI-RADS category-3 to category-5 lesions, 153 were performed in 138 consecutive patients. The
probe was targeted by the stereotactic unit of a prone table (United States Surgical Corporation, Norwalk, Conn.; and Lorad,
Danbury, Conn.). Four to 18 (mean 8) core specimens were obtained for each lesion. In case of complete removal of the lesion,
a localizing clip was deployed at the biopsy site. Adequate material for histopathologic examination was obtained in all cases
(100%). Four of 138 (3%) patients experienced mild hematomas. We observed 15 of 39 failures (38%) to place the localizing
clips. Thirteen of 153 (8%) procedures were inconclusive and required reintervention. Following DVAB, 42 of 138 (30%) patients
underwent surgery. Subject to incomplete follow-up of the entire cohort, we observed no false-positive and one false-negative
diagnosis. These preliminary results suggest that DVAB using an 8-G probe are feasible, safe and accurate. In our experience,
clip placement was problematic. It is probable that increasing the dimensions of DVAB will only be relevant in a limited number
of clinical situations, primarily the desire to obtain complete radiologic resections of the target abnormality.
European Radiology 01/2001; 12(9):2180-2187. · 3.22 Impact Factor
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ABSTRACT: Computed tomographic (CT) pulmonary angiography has been established as a first-line diagnostic technique in patients suspected of having pulmonary embolism. Risk stratification is important in patients with pulmonary embolism because optimal management, monitoring, and therapeutic strategies depend on the prognosis. Acute right-sided heart failure is known to be responsible for circulatory collapse and death in patients with severe pulmonary embolism. Acute right-sided heart failure can be assessed at CT pulmonary angiography by measuring the dimensions of right-sided heart cavities or upstream venous structures, such as the superior vena cava or azygos vein. The magnitude of pulmonary embolism can be calculated at CT pulmonary angiography by applying angiographic scores adapted for CT (Miller and Walsh scores) or dedicated CT scores (Qanadli and Mastora scores). The advent of CT pulmonary angiography performed with electrocardiographic gating permits new advances in assessment of acute right-sided heart failure, such as measurement of the ventricular ejection fraction. Although such findings may be useful for assessment of treatment effectiveness, their effect on prognosis in patients with severe pulmonary embolism is debated in the literature.
Radiographics 26(1):23-39; discussion 39-40. · 2.85 Impact Factor
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ABSTRACT: Persisting chronic edema following postoperative free flap transfer is a common complication. We report 3 cases of successful treatment by selective arterial embolization of the feeding arterial branches without side effect. One session embolization is advocated as a first line treatment of this condition.
CardioVascular and Interventional Radiology 26(3):316-8. · 2.09 Impact Factor
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ABSTRACT: We describe the abnormal magnetic resonance (MR) imaging findings in the deep digital flexor tendon (DDFT) and distal sesamoid bone in horses with radiographic changes compatible with navicular syndrome. Thirteen postmortem specimens were examined using a 1.5-T magnetic field, with spin echo (SE) T1-weighted, turbo SE (TSE) proton density-weighted (with and without fat saturation), and fat saturation TSE T2-weighted sequences. The limbs were then dissected to compare the MR findings with the gross assessment and histologic examination of the DDFT and distal sesamoid bones. Tendonous abnormalities were detected by MR imaging in 12 DDFTs and confirmed at necropsy. Most tendon lesions were located at the level of the distal sesamoid bone and the proximal recess of the podotrochlear bursa. Tendon lesions were classified based on their MR imaging features as core lesions, dorsal lesions, dorsal abrasions, and parasagittal splits. Areas of increased MR signal in the DDFTs were characterized by tendon fiber disturbance and lack of continuity of the collagen fibers, foci of edema, hemorrhages, and formation of lakes containing eosinophilic plasma-like material or amphophilic material of low density. Bone marrow signal alterations in the distal sesamoid bone were seen in all digits. Two main phenomena were responsible for the abnormal signal, respectively, in T1-weighted (decreased signal) and in T2-weighted fat-suppressed images (increased signal): a decrease in the fat marrow content in the trabecular spaces and an increase in the fluid content. Histologic examination revealed foci of bone marrow edema, hemorrhage, necrosis, and fibrosis. Cyst formation and trabecular abnormalities (disorganization, thinning, remodelling) were also observed in areas of abnormal signal intensity. Increased bone density because of trabecular thickening induced a decrease in signal in all sequences.
Veterinary Radiology & Ultrasound 46(4):279-86. · 1.08 Impact Factor
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ABSTRACT: The purpose of this study was to describe the normal magnetic resonance (MR) imaging characteristics of the palmar structures of the equine podotrochlear apparatus by means of retrospective evaluation of MR imaging studies of 16 cadaver limbs. The articular aspect of the distal sesamoid bone was not evaluated in this study. Equine digits were imaged with a human knee radiofrequency coil in a 1.5 T magnetic field, using spin echo (SE) T1-weighted, turbo spin echo proton density (TSE PD)-weighted with and without fat saturation (FS), and FS TSE T2-weighted sequences. The limbs were dissected after imaging to validate the absence of gross abnormalities of the flexor aspect of the distal sesamoid bone, of the deep digital flexor tendon, and the distal impar sesamoidean ligament. Seven deep digital flexor tendons were subjected to histologic examination to exclude any microscopic tendon pathology. The anatomic structures of the podotrochlear apparatus were easily identified on MR images. Compact bone of the flexor cortex of the distal sesamoid bone had low intensity signal on all sequences. In 11 digits an increased signal was seen within the thickness of the sagittal eminence of the flexor cortex in SE T1-weighted images and in TSE PD-weighted images without FS. Trabecular bone had a granular appearance and high signal in SE T1-weighted sequences and TSE images without FS. The deep digital flexor tendon had low signal on FS T2-weighted images, while on short echo time sequences (T1- and PD-weighted sequences), the tendon signal varied depending on the relative orientation between its fibers and the static magnetic field. Seven tendons had stippled appearance due to small intratendonous foci of slightly increased signal on transverse T1-weighted images. MR imaging provides a thorough evaluation of the anatomical structure of the podotrochlear apparatus: A good knowledge of the MR imaging appearance and anatomy and an awareness of potential pitfalls will improve diagnostic specificity for the detection of pathologic changes.
Veterinary Radiology & Ultrasound 45(3):198-204. · 1.08 Impact Factor
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ABSTRACT: The purpose of this study was to describe the computed tomographic (CT) features of nasal aspergillosis in dogs. Initial (n = 35) and follow-up (n = 12) CT images were available from 35 dogs. The most commonly encountered CT findings were (1) moderate to severe cavitary destruction of the turbinates with presence of a variable amount of abnormal soft tissue in the nasal passages, (2) non-specific thickening of the mucosa adjacent to the inner surface of bones of the frontal sinus, maxillary recess and nasal cavity and, (3) thickened reactive bone. The findings were consistent with a disease initially affecting one nasal cavity then progressing into the ipsilateral frontal sinus, the contralateral nasal cavity and the contralateral frontal sinus. Two dogs with associated nasal foreign body had a more localized invasion of the nasal cavity. Attenuation values and contrast enhancement were not specific. With follow-up examinations, a reduction in the amount of abnormal soft tissue was observed in all dogs except one, but this reduction could not be quantified.
Veterinary Radiology & Ultrasound 43(1):5-9. · 1.08 Impact Factor
