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1.
Skeletal Radiol ; 38(6): 559-64, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19234700

RESUMO

OBJECTIVE: A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. MATERIALS AND METHODS: Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16-76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. RESULTS: When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. CONCLUSIONS: The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded.


Assuntos
Fraturas do Fêmur/diagnóstico , Fraturas do Fêmur/etiologia , Necrose da Cabeça do Fêmur/complicações , Necrose da Cabeça do Fêmur/diagnóstico , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
2.
Circulation ; 114(10): 1036-45, 2006 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-16940196

RESUMO

BACKGROUND: Diffusion tensor magnetic resonance imaging (DT-MRI) provides a means for nondestructive characterization of myocardial architecture. We used DT-MRI to investigate changes in direction-dependent water diffusivity to reflect alterations in tissue integrity (trace apparent diffusion coefficients [ADCs] and fractional anisotropy [FA]), as well as indicators of remodeling of fiber helix angles, in patients after myocardial infarction. METHODS AND RESULTS: Thirty-seven patients (35 men, 2 women; median age, 59) after acute myocardial infarction (median interval from onset, 26 days) were enrolled. DT-MRI was performed at the midventricular level to measure trace ADC, FA, and helix angles of myofibers. Helix angles were grouped into left-handed helical fibers, circumferential fibers, and right-handed helical fibers. Measurements were correlated with viability and regional wall motion assessed by contrast-delay-enhancement and cine MRI, respectively. The infarct zone showed significantly increased trace ADC and decreased FA than the remote zone. The percentage of left-handed helical fibers increased from the remote zone (mean +/- SD, 13.3 +/- 5.8%) to the adjacent zone (19.2 +/- 9.7%) and infarct zone (25.8 +/- 18.4%) (MANOVA, P = 0.004). The percentage of right-handed helical fibers decreased from the remote zone (35.0 +/- 9.0%) to the adjacent zone (25.5 +/- 11.5%) and infarct zone (15.9 +/- 9.2%) (P < 0.001). Multiple linear regression showed that the percentage of left-handed helical fibers of the infarct zone was the strongest correlate of infarct size and predictor of ejection fraction. CONCLUSIONS: In vivo DT-MRI of postinfarct myocardium revealed a significant increase in trace ADC and a decrease in FA, indicating altered tissue integrity. The redistribution of fiber architecture correlated with infarct size and left ventricular function. This technique may help us understand structural correlates of functional remodeling after infarction.


Assuntos
Coração/anatomia & histologia , Imageamento por Ressonância Magnética , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Fenômenos Fisiológicos Cardiovasculares , Ecocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/patologia , Pletismografia , Reprodutibilidade dos Testes
3.
AJR Am J Roentgenol ; 187(2): W169-74, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16861506

RESUMO

OBJECTIVE: The objective of our study was to describe MRI features of contracture of the gluteus maximus muscle after providing a retrospective review of the MRI studies of 21 patients. CONCLUSION: Gluteal contracture manifests characteristic features on MRI, including an intramuscular fibrotic cord extending to the thickened distal tendon with atrophy of the gluteus maximus muscle and posteromedial displacement of the iliotibial tract. In advanced cases, medial retraction of the muscle and its tendon results in a depressed groove at the muscle-tendon junction and external rotation of the proximal femur. Clinical correlation and meticulous physical examination may confirm the MR diagnosis.


Assuntos
Contratura/diagnóstico , Imageamento por Ressonância Magnética , Adolescente , Adulto , Nádegas , Pré-Escolar , Feminino , Humanos , Masculino , Estudos Retrospectivos
4.
AJR Am J Roentgenol ; 187(4): 940-3, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16985138

RESUMO

OBJECTIVE: Our purpose was to evaluate the safety and therapeutic efficacy of single-session prolonged alcohol sclerotherapy in treating large hepatic cysts. A therapeutic comparison between 4-hour and 2-hour retention techniques was also studied. MATERIALS AND METHODS: Twenty-seven patients with 31 hepatic cysts were enrolled in this study. Seventeen patients (18 cysts) were treated by alcohol retention for 4 hours (group 1) and 10 patients (13 cysts) for 2 hours (group 2). The mean diameter of the hepatic cysts was 12.4 cm (range, 8-23 cm) with a comparable size range in each group. The sclerosing agent used was 95% alcohol, and the maximum amount was limited to 200 mL. Patients changed position and vital signs were monitored every 10-15 minutes. The blood alcohol concentrations were checked hourly for 5 consecutive hours in the initial nine patients. The nonparametric Mann-Whitney U test was used to compare the difference in characteristics and treatment results of the subjects between these two groups. The level of statistical significance was set at a p value of less than 0.05. RESULTS: All but one patient in group 2 tolerated the entire course of sclerotherapy. The mean aspirated volume and mean injected alcohol volume of the hepatic cysts were 730 mL and 138.3 mL, respectively, in group 1 patients, and 931 mL and 139 mL, respectively, in group 2 patients. The mean maximum blood alcohol concentration was 128.2 mg/dL (range, 60-199 mg/dL) at 3-4 hours after alcohol instillation. The mean posttherapy residual cystic diameter was 2.5 cm (range, 0-6 cm), with an average volume reduction rate of 98.3% and 97.7%, respectively, for patients in group 1 and group 2 after a mean follow-up period of 29.6 months (9-59 months). No statistical differences of the mean reduction rate between the two groups were noted. CONCLUSION: Long retention of the alcohol in a single-injection technique is safe and effective. Two-hour alcohol retention has a comparable efficacy to that of 4-hour retention.


Assuntos
Cistos/terapia , Etanol/administração & dosagem , Hepatopatias/terapia , Soluções Esclerosantes/administração & dosagem , Escleroterapia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia de Intervenção
5.
Korean J Radiol ; 7(2): 118-24, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16799272

RESUMO

OBJECTIVE: We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. MATERIALS AND METHODS: Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patients (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10 mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. RESULTS: No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (+/-standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%+/-9 and 88%+/-6, 41%+/-10 and 88%+/-6, 30%+/-10 and 77%+/-10, and 12%+/-8 and 61%+/-13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%+/-16 and 86%+/-13 vs 45%+/-15 and 73%+/-13 at 6 months, and 25%+/-15 and 71%+/-17 vs 23%+/-17 and 73%+/-13 at 12 months (p = .346 and .224), respectively. CONCLUSION: Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen.


Assuntos
Angioplastia com Balão , Derivação Arteriovenosa Cirúrgica , Oclusão de Enxerto Vascular/terapia , Idoso , Idoso de 80 Anos ou mais , Feminino , Antebraço , Humanos , Masculino , Metais , Pessoa de Meia-Idade , Politetrafluoretileno , Diálise Renal , Stents , Falha de Tratamento , Grau de Desobstrução Vascular
6.
J Chin Med Assoc ; 69(8): 387-90, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16970276

RESUMO

Ureteroarterial fistula is a rare but life-threatening cause of hematuria. The predisposing factors of a ureteroarterial fistula includes pelvic exenteration, radiation therapy, infection, primary vascular disease, vascular reconstructive surgery, and indwelling ureteral catheters or stents. We report a case of ureteroarterial fistula between the right ureter and a pseudoaneurysm originating from the right proximal external iliac artery in a female patient presenting with intermittent massive hematuria. She had previously undergone an operation for cervical cancer, radiation therapy, and ureteral stent placement. She was treated successfully by percutaneous endovascular stent graft placement to exclude the pseudoaneurysm. Percutaneous stent graft placement appears to be an effective and safe therapeutic alternative in the treatment of ureteroarterial fistula.


Assuntos
Stents , Doenças Ureterais/terapia , Fístula Urinária/terapia , Fístula Vascular/terapia , Feminino , Humanos , Pessoa de Meia-Idade
7.
Stroke ; 36(7): 1562-4, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15933251

RESUMO

BACKGROUND AND PURPOSE: Multi-detector computed tomographic (MDCT) angiography is a recently developed imaging technique that can study small vessels such as medullary arteries and veins. The purpose of this study was to evaluate MDCT angiography in diagnosing SDAVF. METHODS: Eight patients with initial magnetic resonance imaging (MRI) and clinical findings suggestive of spinal dural arteriovenous fistula (SDAVF) and 8 control subjects underwent MDCT angiography. Both MDCT angiography and catheter angiography were performed within 5 days in patients with SDAVFs. The results of MDCT angiography in patients with SDAVFs were compared with those of catheter angiography. RESULTS: MDCT angiography detected engorged perimedullary draining veins and correctly localized the fistula of the SDAVFs, and correlated well with catheter angiography. Fistula was at the thoracic level in 7 patients, and sacral level in 1 patient. MDCT angiography did not visualize the engorged perimedullary venous plexus in the control group. CONCLUSIONS: MDCT angiography correlated well with catheter angiography in diagnosing SDAVFs. It might play a role in shortening the length of the catheter angiography in diagnosing this disease.


Assuntos
Angiografia/métodos , Fístula Arteriovenosa/diagnóstico , Malformações Vasculares do Sistema Nervoso Central/diagnóstico , Medula Espinal/patologia , Tomografia Computadorizada por Raios X/métodos , Estudos de Casos e Controles , Sistema Nervoso Central/patologia , Malformações Vasculares do Sistema Nervoso Central/patologia , Humanos , Reprodutibilidade dos Testes , Coluna Vertebral/patologia , Fatores de Tempo
8.
Am Heart J ; 149(4): 701-8, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15990756

RESUMO

BACKGROUND: Recent studies reveal that contrast-enhanced multidetector row computed tomography (MDCT) is a promising technique for noninvasive visualization of coronary artery stenoses. We investigated the safety and accuracy of MDCT for early assessment of the severity of residual stenosis of the infarct-related artery (IRA) and the number of diseased vessels in patients after acute myocardial infarction (AMI). METHODS AND RESULTS: Of 146 AMI cases admitted, 72 fit with criteria and underwent 16-slice MDCT (4 +/- 2 days after AMI) with beta-blockers. There were no complications except 1 patient who had from complete atrioventricular block. Results were compared with conventional coronary angiography (CCA) within 3 days. In 55 (73.3%) of 72 patients, all arteries were assessable. In total, the number of assessable arteries was 253 (87.8%), and 35 (12.2%) vessels were nonassessable, mostly because of motion artifacts and extensive calcification. Overall, 84 of the 115 lesions (> or = 50% lumen reduction) were correctly detected by MDCT (sensitivity 73.0%). The accuracy in classifying patients with nonsignificant, single-, or multiple-vessel diseases was 79.1%. The accuracy for residual lesions with >50% stenosis of IRA was 87.5%. There was a good correlation regarding the severity of residual stenosis of the IRA (0%, 1%-49%, 50%-89%, 90%-99%, or occlusion) between MDCT and CCA (Spearman correlation 0.94, P < .001). Lesions with 90% to 99% or occlusion of the IRA were accurately detected or ruled out in 31 of 36 cases (86.1%). CONCLUSIONS: With appropriate protocol, MDCT is safe and accurate in assessing the severity of IRA and the number of diseased vessels during the first week after AMI. It has the potential to provide triage for early management of patients after AMI.


Assuntos
Estenose Coronária/diagnóstico por imagem , Infarto do Miocárdio/etiologia , Tomografia Computadorizada Espiral , Antagonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/uso terapêutico , Idoso , Artefatos , Calcinose/complicações , Calcinose/diagnóstico por imagem , Comorbidade , Angiografia Coronária , Estenose Coronária/complicações , Vasos Coronários/patologia , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Metoprolol/farmacologia , Metoprolol/uso terapêutico , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/tratamento farmacológico , Oxigênio/administração & dosagem , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Tomografia Computadorizada Espiral/efeitos adversos
9.
J Chin Med Assoc ; 68(3): 131-7, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15813247

RESUMO

BACKGROUND: Acute subarachnoid hemorrhage (SAH) has traditionally been diagnosed by computed tomography (CT); however, fluid-attenuated inversion recovery (FLAIR) is a magnetic resonance imaging (MRI) modality currently used to detect acute SAH. CT is insensitive in the detection of subacute or chronic SAH. The purpose of this study was to compare 4 MRI pulse sequences and CT in the detection of SAH in acute and subacute-to-chronic stages. METHODS: From 2001-2003, we collected data for 22 patients (12 men and 10 women, aged 35-80 years) with SAH due to ruptured aneurysm (n = 11), trauma (3), or unknown origin (8). All patients underwent MRI and CT examination, with an interval of less than 12 hours between the 2 procedures. We divided patients into 2 groups according to the time from symptom onset to MRI evaluation: patients with MRI performed < or = 5 days post-ictus had acute-stage illness, whereas patients with MRI performed from day 6-30 post-ictus had a subacute-to-chronic condition. MRI (1.5-T) pulse sequences comprised spin-echo T1-weighted, fast spin-echo T2-weighted, FLAIR, and gradient-echo (GE) T2*-weighted images. RESULTS: In the acute-stage group, SAH was seen as an area of high signal intensity compared with surrounding cerebrospinal fluid in 36.4% of cases on T1-weighted images, and in 100% on FLAIR images; low signal intensities were seen in 18.2% of cases on T2-weighted images, and in 90.9% on GE T2*-weighted images. High-attenuated SAH was seen on CT in 90.9% of cases. FLAIR (p = 0.008), GE T2*-weighted images (p = 0.012) and CT images (p = 0.012) were all statistically significant indicators of acute SAH. In the subacute/chronic-stage group, SAH was detected on T1-weighted images (36.4% of cases), FLAIR (33.3%), T2-weighted images (9.1%), GE T2*-weighted images (100%), and CT (45.5%). GE T2*-weighted images were significantly superior (p = 0.001) to other MRI pulse sequences and CT as indicators of subacute-to-chronic SAH. CONCLUSION: FLAIR and GE T2* MRI pulse sequences, and CT scans, are all statistically significant indicators of acute SAH. GE T2*-weighted images are statistically significant indicators of subacute-to-chronic SAH, whereas other MRI pulse sequences, and CT scans, are not.


Assuntos
Imageamento por Ressonância Magnética , Hemorragia Subaracnóidea/diagnóstico , Tomografia Computadorizada por Raios X , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Aneurisma Roto/complicações , Lesões Encefálicas/complicações , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Hemorragia Subaracnóidea/etiologia
10.
Clin Imaging ; 28(6): 408-14, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15531140

RESUMO

PURPOSE: To assess the feasibility of low-dose CT (LDCT) in the detection of pulmonary metastases in patients with primary gynecologic malignancies and also to compare the performance of chest digital radiography (DR) and LDCT for their delectability of pulmonary metastases, with use of standard-dose CT (SDCT) as the reference standard. MATERIALS AND METHODS: Thirty female patients with primary gynecologic malignancies (age range, 20-76 years; mean age, 50 years) underwent DR, noncontrast LDCT and contrast-enhanced SDCT, which were performed within an interval of 2 weeks. We used lung nodule, mediastinal lymphadenopathy (>10 mm in the short axis) and pleural changes (including effusion, irregular thickening, or nodularity) as the cardinal imaging findings of lung metastases. A five-point scoring system was designed to indicate the probability of lung metastasis from primary gynecologic malignancies. The five-point scores of DR, LDCT, and SDCT were analyzed by receiver operating characteristic (ROC) curve. RESULTS: SDCT probability scores of +2 and -2 were set to indicate true positive and true negative for pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion, respectively. All the areas under the ROC curve of LDCT appeared to be larger than those of DR[pulmonary nodule: 0.96 [95% confidence interval (CI): 0.92-1.01] vs. 0.74 [95% CI: 0.57-0.91], 0.82 [95% CI: 0.70-0.95] vs. 0.61 [95% CI: 0.50-0.77]; mediastinal lymphadenopathy: 0.98 [95% CI: 0.93-1.03] vs. 0.90 [95% CI: 0.79-1.01], 0.94 [95% CI: 0.82-1.06] vs. 0.66 [95% CI: 0.44-0.88]; and pleural effusion: 0.98 [95% CI: 0.93-1.03] vs. 0.56 [95% CI: 0.29-0.82], 0.90 [95% CI: 0.74-1.05] vs. 0.46 [95% CI: 0.23-0.68]]. CONCLUSION: The performance of LDCT were comparable to those of SDCT and superior to those of DR for detection of pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion. By using LDCT, there was no need of intravenous contrast injection and less radiation exposure. We propose a protocol including standard-dose abdominal CT and low-dose chest CT for the initial and follow-up stagings of primary gynecologic malignancy. The use of chest DR is unnecessary.


Assuntos
Neoplasias dos Genitais Femininos/patologia , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/secundário , Doenças Linfáticas/patologia , Intensificação de Imagem Radiográfica , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Área Sob a Curva , Estudos de Coortes , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Probabilidade , Estudos Prospectivos , Doses de Radiação , Medição de Risco , Sensibilidade e Especificidade
11.
Clin Imaging ; 28(1): 10-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-14996441

RESUMO

BACKGROUND AND PURPOSE: Cystic meningiomas are quite rare, accounting for between 2% and 4% of all intracranial meningiomas. To better understand all the types of cystic meningiomas with magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and histopathology, we attempted to correlate the MRI and DWI features of cystic meningiomas with the histopathological findings. METHODS: We collected 15 cases of cystic meningiomas diagnosed between 1993 and 2000 (5 men and 10 women, 41-80 years old). Fifteen patients had conventional MRI and 14 patients had CT scan. DWI was also performed in three patients. Apparent diffusion coefficient (ADC) images were also done. In the classification of cystic meningiomas, we adopted Worthington's classification, which divides cystic meningiomas into five groups. RESULTS: Tumor resection was performed in all patients. Tumor locations were as follows: convexity (10), falx (2), pterion (2) and lateral ventricle (1). Regarding the types of cystic lesion, type I (3), type II (3), type III (3), type IV (1) and type V (5) were found. Histopathologically, there were six atypical, four meningothelial, two malignant, one fibroblastic, one angiomatous and one transitional. Intratumoral cystic meningiomas were more common in atypical types. Peritumoral cystic meningiomas were more common in meningothelial and atypical types. The cystic portion of the three cystic meningiomas was hypointense or mildly hyperintense on DWI. ADC ratio (ADCR) of DWI for cyst part of two type I cystic meningiomas was 1.25 and 0.82; for cyst part of one type III was 4.04. CONCLUSIONS: It is important to recognize the neuroimaging features of the cystic meningiomas. Conventional MRI and DWI may play an important role in the preoperative radiological evaluation and the recognition of these types of cysts for proper surgical treatment.


Assuntos
Cistos/patologia , Imagem de Difusão por Ressonância Magnética , Imageamento por Ressonância Magnética , Neoplasias Meníngeas/patologia , Meningioma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste/administração & dosagem , Cistos/classificação , Feminino , Gadolínio DTPA/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estatística como Assunto , Tomografia Computadorizada por Raios X
12.
Clin Imaging ; 26(4): 227-36, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12140151

RESUMO

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) can be used to distinguish brain abscesses from cystic or necrotic brain tumors, which are difficult to distinguish by conventional magnetic resonance imaging (MRI) techniques. METHODS: Eleven consecutive patients with brain abscesses [10 pyogenic and 1 toxoplasmosis (in an AIDS patient)] and 15 with cystic or necrotic brain gliomas or metastases were enrolled in this study. None of these lesions had apparent hemorrhage based on T1-weighted image (T1WI). The DWI was performed using a 1.5-T system, single-shot spin-echo echo-planar pulse sequence with b=1000 s/mm(2). The ADC was calculated using a two-point linear regression method at b=0 and b=1000 s/mm(2). The ratio (ADCR) of the lesion ADC to control region ADC was also measured. RESULTS: Increased signal was seen in all of the pyogenic abscess cavities to variable degrees on DWI. In vivo ADC maps showed restricted diffusion in the abscess cavity in all pyogenic abscesses [0.65+/-0.16 x 10(-3) (mean+/-S.D.) mm(2)/s, mean ADCR=0.63]. The case with multiple toxoplasmosis abscesses showed low signal intensity on DWI and high ADC values (mean 1.9 x 10(-3) mm(2)/s, ADCR=2.24). All cystic or necrotic tumors but one showed low signal intensity on DWI and their cystic or necrotic areas had high ADC values (2.70+/-0.31 x 10(-3) mm(2)/s, mean ADCR=3.42). One fibrillary low-grade astrocytoma had a high DWI signal intensity and a low ADC value in its central cystic area (0.44 x 10(-3) mm(2)/s, ADCR=0.49). Postcontrast T1WIs yielded a sensitivity of 60%, a specificity of 27.27%, a positive predictive value (PPV) of 52.94%, and a negative predictive value (NPV) of 33.33% in the diagnosis of necrotic tumors. DWI yielded a sensitivity of 93.33%, a specificity of 90.91%, a PPV of 93.33%, and a NPV of 90.91%. The area under receiver operating characteristic (ROC) curves for postcontrast T1WI was 0.44 and DWI was 0.92. Analysis of these areas under the ROC curves indicates significant difference between postcontrast T1WI and DWI (P<.001). CONCLUSION: With some exceptions, DWI is useful in providing a greater degree of confidence in distinguishing brain abscesses from cystic or necrotic brain tumors than conventional MRI and seems to be a valuable diagnostic tool.


Assuntos
Abscesso Encefálico/diagnóstico , Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Imageamento por Ressonância Magnética/métodos , Encéfalo/patologia , Neoplasias Encefálicas/secundário , Estudos de Casos e Controles , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Toxoplasmose Cerebral/diagnóstico
13.
J Chin Med Assoc ; 67(7): 369-72, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15510936

RESUMO

Dorsal defect of the patella (DDP) is an uncommon but well-documented disease entity. We report a case of bilateral DDP with patellar hypoplasia and patello-femoral malalignment. Detailed imaging features including radiographic, magnetic resonance imaging, and computed arthrotomographic appearances, are described.


Assuntos
Mau Alinhamento Ósseo/complicações , Patela/anormalidades , Adulto , Mau Alinhamento Ósseo/patologia , Humanos , Joelho/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Patela/diagnóstico por imagem , Patela/patologia , Tomografia Computadorizada por Raios X
14.
J Chin Med Assoc ; 66(3): 166-72, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12779037

RESUMO

BACKGROUND: Central venous obstruction is a serious and common complication in hemodialysis patients. The recurrence rate is high after balloon dilation, while surgical repair is hazardous in these chronically ill patients. The aim of this study was to evaluate the efficacy of primary Wallstent placement for treatment of hemodialysis-related central venous obstructions. METHODS: Eighteen hemodialysis patients with symptomatic shunt dysfunction and arm swelling due to subclavian (n = 3) or innominate (n = 15) venous obstructions were treated at Kaohsiung Veterans General Hospital with primary Wallstent placement from November 1998 to August 2001. Technical success and complications were reported. Primary and secondary patency rates of stent and hemodialysis access were calculated by survival analysis with Kaplan-Meier method. RESULTS: A total of twenty-five Wallstents were deployed for central venous stenosis (n = 18) and occlusion (n = 7) in these 18 hemodialysis patients. The initial technical success rate was 100%. Fourteen episodes of re-obstruction developed during the observation period. Of them, seven episodes occurred within the stent, four episodes outside of but abutting to the peripheral end of the stent, and another three episodes of re-obstruction were attributed to delayed shortening of the Wallstent. Six of the 14 episodes were treated percutaneously with angioplasty alone, while seven episodes necessitated additional stent placement. No stent migration or other complications were encountered. Primary patency rates of stent and hemodialysis access at 3, 6, 12 and 18 months were 100 and 89%, 73 and 68%, 49 and 42%, and 16 and 0%, respectively. Secondary patency rates of stent and hemodialysis access each were both 100% after 3 months, 93 and 100% after 6 months, 85 and 91% after 12 months and, 68 and 72% after 24 months. CONCLUSIONS: Wallstents are safe to deploy, with excellent technical success for hemodialysis-related central venous obstructions. The Wallstent provides continued use of a hemodialysis access for a substantial period. However, repeated interventions may be necessary to maintain the patency.


Assuntos
Cateterismo Venoso Central/efeitos adversos , Diálise Renal/efeitos adversos , Stents , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Kaohsiung J Med Sci ; 20(8): 381-8, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15473649

RESUMO

Posterior reversible encephalopathy syndrome (PRES) is a potentially devastating neurologic syndrome, but timely treatment may lead to complete reversal of the disease course. We reviewed 12 cases of PRES and describe the clinical history and imaging findings, including conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and calculated apparent diffusion coefficient (ADC) maps, used to establish the diagnosis of PRES. Three male and nine female patients aged between 11 and 70 years (mean, 37 years) with clinical and imaging findings consistent with PRES were enrolled in the study. All patients had undergone conventional MRI and 10 had undergone additional DWI studies. Ten patients had follow-up MRI studies. DWI was performed using a 1.5T system with a single-shot spin-echo echoplanar pulse sequence. Initial and follow-up neuroimaging and clinical history were reviewed. Lesions were almost always present over the posterior circulation, mainly the parieto-occipital region, affecting primarily the white matter. The anterior circulation region, brainstem, cerebellum, deep cerebral white matter, and thalamus were also involved in five cases. Conventional MRI revealed hyperintensity on T2-weighted and fluid-attenuated inversion recovery images. DWI showed isointensity and increased signal intensity on ADC values in all cases, indicating vasogenic edema. Clinical and MRI follow-up showed that the symptoms and radiologic abnormalities could be reversed after appropriate treatment of the causes of PRES in most patients (9 of 10). In one patient, the ADC value was lower on follow-up images, indicating cytotoxic edema with ischemic infarct. DWI was a useful complement to MRI in the diagnosis of PRES.


Assuntos
Encéfalo/patologia , Hipóxia-Isquemia Encefálica/patologia , Adolescente , Adulto , Idoso , Criança , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Encefalopatia Hipertensiva/patologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Síndrome
18.
Acta Radiol ; 48(7): 734-40, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17729003

RESUMO

BACKGROUND: A permanent reservoir implantation is considered mandatory for hepatic arterial infusion chemotherapy (HAIC) of hepatocellular carcinoma (HCC). Since treatment sessions of HAIC may be limited for these end-staged patients, a simple alternative technique for this treatment is desirable. PURPOSE: To evaluate the feasibility of placing a temporary catheter for HAIC in advanced HCC patients. MATERIAL AND METHODS: 25 advanced HCC patients underwent HAIC with drugs delivered from a temporary catheter which was placed percutaneously by puncturing the left subclavian artery under ultrasound guidance. A course of chemotherapy consisted of five consecutive daily infusions of 5-fluorouracil, cisplatin, mitomycin C, and leucovorin. The catheter was removed on the 6th day. Therapy was repeated every 4-6 weeks with maximal number of courses of up to six. The total courses of HAIC in each patient, the catheter-placed-related complications, tumor response rate, and median survival of the patients were registered. RESULTS: A total of 77 courses of HAIC were performed with 100% technical success of catheter placement (1-6 courses in each patient, average 3.1 courses). The overall response rate was 20%, with complete response in two patients and partial response in three patients. Eleven (55%) of the 20 non-responders died within 5 months (mean HAIC, two courses). None of the patients experienced complications such as catheter occlusion, hepatic arterial thrombosis, cerebral infarction, or local infection. CONCLUSION: With fewer catheter-related complications, HAIC by temporary catheter placement via subclavian puncture could be a treatment option.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Adulto , Idoso , Antineoplásicos/administração & dosagem , Carcinoma Hepatocelular/patologia , Cateteres de Demora , Esquema de Medicação , Estudos de Viabilidade , Seguimentos , Humanos , Infusões Intra-Arteriais , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento
19.
Cardiovasc Intervent Radiol ; 29(5): 890-2, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16565793

RESUMO

Ruptured mycotic pulmonary pseudoaneurysm is a lethal complication. Emergent surgical repair is usually recommended, but still associated with a high mortality rate. We present a patient in whom mycotic pulmonary pseudoaneurysm was a complication after surgical lobectomy 2 weeks earlier. This patient had suffered from repeated massive hemoptysis. After emergent surgical repair of the ruptured pulmonary artery stump, another episode of massive hemorrhage occurred. The pulmonary arteriogram revealed a segmental stenosis and a large, wide-necked, lobulated pseudoaneurysm at the left proximal pulmonary artery. We deployed a balloon-expandable stent-graft (48 mm in length mounted on a 12 mm x 40 mm angioplasty balloon) across the stenotic segment and the neck of the pulmonary pseudoaneurysm. Hemostasis was achieved immediately and, under a 4-week antibiotic treatment, patient was transferred to a local hospital for medical care. This case report demonstrates the benefit of minimally invasive endovascular therapy in a critically ill patient. A literature review of the etiology and management of mycotic pulmonary pseudoaneurysm is included.


Assuntos
Falso Aneurisma/terapia , Aneurisma Infectado/terapia , Aneurisma Roto/terapia , Angioplastia com Balão , Implante de Prótese Vascular , Artéria Pulmonar , Stents , Falso Aneurisma/diagnóstico por imagem , Aneurisma Infectado/tratamento farmacológico , Aneurisma Infectado/microbiologia , Infecções por Bactérias Gram-Negativas/complicações , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Pulmonar/diagnóstico por imagem , Radiografia , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/tratamento farmacológico , Stenotrophomonas maltophilia
20.
Magn Reson Med ; 56(3): 517-26, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16902978

RESUMO

A temporal correlation (TC) mapping method is proposed to help bolus chasing during dynamic contrast-enhanced (DCE) MRI of complex pulmonary circulation (CPC) in patients with congenital heart disease. DCE-MRI was performed on five healthy male subjects (23-24 years old) and 25 patients (nine males and 16 females, 0.25-44 years old), and TC maps were generated by performing pixel-based computation of cross-correlations to the pulmonary artery with a series of time shifts in all subjects. Qualitative and quantitative evaluations were performed in comparison with original DCE images. TC maps exhibited a better signal-to-noise ratio (SNR) by factors of 4.3 and 1.3 in the lung parenchyma, pulmonary veins, and superior artery/vein; a better intraparenchymal contrast-to-noise ratio (CNR) by factors of 1.5-5.4; and a significantly higher conspicuity in all regions except the pulmonary arteries when graded with a five-point score. TC maps evaluated by two experienced clinicians significantly added relevant information (P<0.001), and in some cases affected the final diagnosis. We conclude that TC maps facilitate bolus chasing for DCE-MRI by reducing recirculation effects and interframe fluctuations, and hence complements morphological imaging of CPC in patients with complex congenital heart disease.


Assuntos
Cardiopatias Congênitas/complicações , Cardiopatias Congênitas/diagnóstico , Aumento da Imagem/métodos , Pneumopatias/diagnóstico , Pneumopatias/etiologia , Imageamento por Ressonância Magnética/métodos , Circulação Pulmonar , Adolescente , Adulto , Criança , Pré-Escolar , Meios de Contraste , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Lactente , Masculino
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