RESUMEN

The purpose of this study was to compare the performance of magnetic resonance (MR) imaging using currently available techniques with contrast-enhanced single-phase helical computed tomography (CT) in depicting extrahepatic disease in patients with malignancy. At two institutions, 164 patients with known or suspected malignancy underwent abdominal imaging with contrast-enhanced helical CT and MR imaging. The prospective interpretations of the CT scans and MR examinations were used to assess the sensitivity of each imaging test in detecting benign and malignant extrahepatic disease at 17 anatomic sites. Imaging findings were compared with results of surgery in 57 patients and with the combined results of image-guided biopsy, follow-up cross-sectional imaging studies, other concurrent imaging tests, and clinical follow-up. For the 164 patients, helical CT scans depicted 221 of 316 (70%) sites of proven extrahepatic tumor compared with 288 sites (91%) (P < 0.0001) for MR imaging. For the 57 patients who underwent exploratory laparotomy, helical CT scans depicted 101 of 154 (66%) findings of surgically confirmed extrahepatic tumor compared with MR imaging, which depicted 139 sites (90%) (P < 0.0001). Anatomic sites at which MR imaging showed a significantly greater detection of extrahepatic tumor included the peritoneum, bowel, and vascular and osseous structures. For depiction of benign extrahepatic disease, there was no significant difference between helical CT and MR imaging. MR imaging, using currently available T1-weighted, RARE T2-weighted, and gadolinium-enhanced imaging, is effective in depicting extrahepatic disease in patients with malignancy. Compared with single-phase helical CT scanning, MR imaging shows an advantage in depicting tumor involving the peritoneum, omentum, bowel, and osseous and vascular structures.

Asunto(s)

Neoplasias Abdominales/diagnóstico , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X , Neoplasias Abdominales/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Medios de Contraste , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sensibilidad y Especificidad

RESUMEN

BACKGROUND: To report the observation that chemotherapy-treated liver metastases may mimic the appearance of hemangiomas on T2-weighted and serial postgadolinium gradient-echo magnetic resonance (MR) images. METHODS: T2-weighted and serial postgadolinium spoiled gradient-echo images were prospectively and retrospectively analyzed in six patients. All patients had been treated with chemotherapy for a duration of 2-12 months. Histopathologic evaluation of liver lesions was performed in three patients. RESULTS: Twelve lesions that resembled hemangiomas were identified. Lesions were 0.8-5.5 cm in diameter. All were well defined, oval or lobulated, and demonstrated decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. On immediate postgadolinium images, all lesions demonstrated peripheral nodular enhancement, which coalesced on delayed imaging. Final histopathologic diagnoses were as follows: hepatic metastases from colon cancer (two patients), ovarian cancer (two patients), pancreatic islet cell tumor (one patient), and breast cancer (one patient). CONCLUSIONS: Metastases treated by chemotherapy may mimic the appearance of hemangiomas on a variety of commonly employed MR techniques. In patients undergoing MR imaging for the evaluation of liver metastases, a history of prior chemotherapy administration and duration should be sought to prevent inaccurate staging and inappropriate therapeutic decision making.

Asunto(s)

Hemangioma/diagnóstico , Neoplasias Hepáticas/diagnóstico , Imagen por Resonancia Magnética , Anciano , Antineoplásicos/uso terapéutico , Medios de Contraste , Diagnóstico Diferencial , Femenino , Gadolinio , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/secundario , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos

RESUMEN

This study evaluates a combined protocol consisting of breath hold immediate post gadolinium 3-D gradient echo MR angiography and blood pool phase gadolinium-enhanced breath hold 2-D fat-suppressed spoiled gradient echo (SGE) sequences in the examination of diseases of the abdominal aorta and iliac vessels. Thirty-two patients with suspected disease of the abdominal aorta, major aortic branches, or iliac vessels underwent MR angiographic study from January 1996 to January 1997. Examinations were performed on a 1.5 T MR imager using 2-D axial SGE, coronal 3-D fast imaging in steady state precession (3-D FISP) following bolus administration of 40 mL of gadolinium, and axial and coronal blood pool phase gadolinium-enhanced fat-suppressed SGE. Post-processed data, including 3-D reconstructions using maximum intensity projection (MIP), targeted MIP, and multiplanar reconstruction (MPR) were evaluated. MR findings in all patients were correlated as follows: surgery (13 patients), angiography (11 patients), contrast enhanced CT (3 patients), non-contrast enhanced CT (1 patient), color doppler US (2 patients), and previous MR study (2 patients). MR findings correlated closely with findings at surgery or other imaging studies in 31 of 32 patients. One patient had renal artery occlusion that was misinterpreted as mild stenosis. The following vascular diseases were present: aneurysm disease [10 patients: aortic aneurysm (8 patients), inflammatory aneurysm (2 patients)], thoracoabdominal aortic dissection (2 patients), arteriovenous fistula (1 patient), stenoses and/or occlusion of the abdominal aorta, major aortic branches and iliac vessels [12 patients: stenoses and/or occlusion of the abdominal aorta with stenoses of the iliac vessels (9 patients), renal artery stenosis (2 patients), occlusion of the abdominal aorta (1 patient)], and occluded artery to pancreatic transplant artery (1 patient). Five patients had normal studies. The 3-D FISP technique accurately defined the luminal contours of vessels, allowing precise depiction of vessel stenosis (i.e., renal artery stenosis or common iliac artery stenosis) and clear demonstration of relationship of aortic branch vessels (i.e., renal arteries) to underlying aortic pathology (i.e., aortic aneurysm or dissection). Blood pool phase gadolinium-enhanced fat-suppressed SGE images were useful in the evaluation of the external surface of vessel walls, and providing accurate measurement of aneurysm diameter and other associated vascular entities (i.e., inflammatory aneurysm, left-sided IVC). Targeted MIP or MPR reconstruction were important for assessing stenoses of medium sized vessels such as renal arteries and branches of the iliac arteries, and for identifying accessory arteries. The combination of immediate post gadolinium 3-D FISP and blood pool phase gadolinium-enhanced fat-suppressed SGE is useful in the evaluation of the abdominal aorta, major aortic branches and iliac vessels. Immediate post gadolinium 3-D FISP images provides diagnostically useful information regarding vessel luminal contour, while blood pool phase gadolinium-enhanced fat-suppressed SGE provides ancillary information on the vessel wall and surrounding tissue.

Asunto(s)

Aorta Abdominal , Arteria Ilíaca , Vena Ilíaca , Angiografía por Resonancia Magnética , Enfermedades Vasculares/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades de la Aorta/diagnóstico , Medios de Contraste , Femenino , Gadolinio , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino

RESUMEN

PURPOSE: To compare state-of-the-art magnetic resonance (MR) imaging with single-phase helical computed tomography (CT) in abdominal screening for extrahepatic disease in patients with proved malignancy. MATERIALS AND METHODS: Fifty-seven patients with known malignancy underwent abdominal contrast material-enhanced helical CT and MR imaging from 1994 through 1997. Prospective interpretations of CT scans and MR images were used to assess each modality's sensitivity in depicting malignant extrahepatic tumor at 17 anatomic sites. Imaging findings were compared with surgical results in all patients. RESULTS: Helical CT depicted 101 (66%) of 154 surgically confirmed extrahepatic tumor sites; MR imaging depicted 139 (90%) (P < .001). MR imaging depicted tumor in more patients at 11 of the 17 anatomic sites; at six sites, MR imaging and helical CT were equivalent. MR imaging showed significantly greater depiction of extrahepatic tumor for the peritoneum (P < .05), bowel (P < .01), and mesentery (P < .05). False-negative interpretations would have altered patient care had the extrahepatic tumor remained undetected in 13 patients for helical CT and in six patients for MR imaging. CONCLUSION: State-of-the-art MR imaging can be used for effective abdominal screening for extrahepatic tumor in patients with malignancy. Compared with single-phase helical CT, MR imaging depicted more sites of extrahepatic tumor and was particularly advantageous for the peritoneum, mesentery, and bowel.

Asunto(s)

Neoplasias Abdominales/diagnóstico , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X/métodos , Neoplasias Abdominales/diagnóstico por imagen , Neoplasias Abdominales/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Medios de Contraste , Diatrizoato , Reacciones Falso Negativas , Femenino , Estudios de Seguimiento , Gadolinio DTPA , Humanos , Neoplasias Intestinales/diagnóstico , Neoplasias Intestinales/diagnóstico por imagen , Neoplasias Intestinales/cirugía , Yohexol , Laparotomía , Imagen por Resonancia Magnética/métodos , Masculino , Mesenterio/diagnóstico por imagen , Mesenterio/patología , Mesenterio/cirugía , Persona de Mediana Edad , Neoplasias Peritoneales/diagnóstico , Neoplasias Peritoneales/diagnóstico por imagen , Neoplasias Peritoneales/cirugía , Estudios Prospectivos , Sensibilidad y Especificidad , Método Simple Ciego

RESUMEN

We evaluated the ability of current magnetic resonance (MR) scanning techniques to detect and stage neuroblastoma in children, using surgical and histopathologic correlation. We prospectively and retrospectively reviewed 16 MR examinations from 14 patients with neuroblastoma (13 patients) or ganglioneuroblastoma (1 patient) and compared these to computed tomography (CT) (5 patients) and pathology (all patients). Sequences included: precontrast T1-weighted and T2-weighted images, and gadolinium-enhanced T1-weighted images. The study time for each MR exam was also calculated. Five primary tumors were intrathoracic paraspinous masses, eight were adrenal, and 1 was presacral. Neural foraminal invasion was demonstrated on MR in four of 14 patients. Three of the four patients had undergone CT and neural foraminal invasion was shown in one. Vascular encasement was demonstrated in five of 14 patients on MR images. Three of the five patients had undergone CT and vascular involvement was shown in two. All cases of neural foramina invasion and vascular encasement were proven at surgery. There were no false positive or false negative MR studies of neural foraminal invasion or vascular encasement. Bone marrow invasion was shown in two of 14 patients on MR images which were confirmed by bone marrow aspirate. No false negative cases of bone marrow invasion was shown. In one patient, CT considered one neuroblastoma to be adrenal in location which was correctly shown to be intrathoracic on MR. The mean study time for MR imaging was 49 min. Current MR techniques are accurate at detecting and staging neuroblastoma, and coverage of chest, abdomen, and pelvis can be performed in less than one hour.

Asunto(s)

Imagen por Resonancia Magnética/métodos , Neuroblastoma/diagnóstico , Neoplasias de las Glándulas Suprarrenales/diagnóstico , Neoplasias de las Glándulas Suprarrenales/patología , Preescolar , Femenino , Humanos , Masculino , Estadificación de Neoplasias , Neuroblastoma/patología , Estudios Prospectivos , Estudios Retrospectivos , Neoplasias Torácicas/diagnóstico , Neoplasias Torácicas/patología , Tomografía Computarizada por Rayos X

RESUMEN

We report a case of a 41-year-old patient with multiple pulmonary aneurysms secondary to Hughes-Stovin syndrome. Conventional pulmonary angiography could not be performed, because thrombus in both the inferior and superior vena cavae prevented catheter passage. Contrast-enhanced three-dimensional (3D) MR angiography (MRA) showed two segmental pulmonary aneurysms in the right lung. The affected segments of the lung were resected successfully, predicated on the MRA findings.

Asunto(s)

Aneurisma/diagnóstico , Angiografía por Resonancia Magnética , Arteria Pulmonar/patología , Tromboembolia/complicaciones , Tromboflebitis/complicaciones , Adulto , Aneurisma/etiología , Aneurisma Falso/complicaciones , Medios de Contraste/administración & dosificación , Gadolinio DTPA/administración & dosificación , Humanos , Aneurisma Ilíaco/complicaciones , Inyecciones Intravenosas , Masculino , Arteria Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Vena Cava Inferior/patología , Vena Cava Superior/patología

RESUMEN

This study describes the spectrum of appearances of cholangiocarcinoma on magnetic resonance (MR) sequences, including gadolinium-enhanced, fat-suppressed spoiled gradient echo images and MR cholangiography. Fifteen patients were included in the study. Histologic diagnosis was established in 11 patients by surgical resection (6 patients), percutaneous biopsy (4 patients), and open liver biopsy (1 patient). The final diagnosis was determined by correlation of the MR findings with cholangiographic studies and laboratory studies in 4 patients. MR studies were performed at 1.5 T, and the following sequences were obtained: T1-weighted spoiled gradient echo (SGE), T1-weighted fat-suppressed spin echo or SGE, T2-weighted fat-suppressed conventional or turbo spin echo, MR cholangiography, and gadolinium-enhanced T1-weighted fat-suppressed SGE images. The following determinations were made: tumor location, tumor extent, ductal dilatation, ductal wall thickness, signal intensity, enhancement pattern, and associated findings. Mass-like neoplasms were peripheral (6 patients), hilar (1 patient), and extrahepatic (2 patients). Circumferential tumors were hilar (2 patients) and extrahepatic (4 patients). All peripheral tumors were multifocal. Mass-like tumors were well-defined, rounded, and ranged from 1 to 14 cm in diameter. Circumferential tumors had less well-defined margins and measured from 3 to 15 mm in thickness. All mass-like tumors were moderately hypointense on T1-weighted images and mildly to moderately hyperintense on T2-weighted images. The circumferential tumors were iso- to moderately hypointense on T1-weighted images and iso- to mildly hyperintense on T2-weighted images. Mass-like tumors were generally well shown on non-contrast and immediate gadolinium-enhanced images, whereas circumferential tumors were poorly seen on non-contrast images and best shown on gadolinium-enhanced T1-weighted fat-suppressed images. The degree of enhancement ranged from minimal to intense on immediate gadolinium-enhanced images, with all tumors becoming more homogeneous in signal intensity on images obtained between 1 and 5 min following contrast administration. Tumor-containing lymph nodes greater than or equal to 1 cm in diameter were demonstrated in 11 out of 15 patients (73.3%). These were best shown on T2-weighted fat-suppressed images and gadolinium-enhanced fat-suppressed SGE images. MR cholangiography demonstrated the level of obstruction and degree of dilatation of the proximal biliary system in 5 out of 6 patients who underwent MR cholangiography. The spectrum of appearances of cholangiocarcinoma is demonstrable on MR images. Mass-like tumors are well shown on both pre- and post-gadolinium sequences. Circumferential tumors may cause minimally increased duct wall thickness and are most clearly shown on gadolinium-enhanced fat-suppressed SGE images obtained 1 to 5 min following gadolinium administration.

Asunto(s)

Neoplasias de los Conductos Biliares/diagnóstico , Conductos Biliares Intrahepáticos/patología , Colangiocarcinoma/diagnóstico , Imagen por Resonancia Magnética/métodos , Adulto , Anciano , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Imagen por Resonancia Magnética/instrumentación , Masculino , Persona de Mediana Edad , Estudios Retrospectivos

RESUMEN

The purpose of this study is to describe the appearance of bowel-related abscesses on magnetic resonance (MR) images. Sixteen consecutive patients who had bowel-related abscesses underwent MR examination at 1.5T. MR sequences included T1-weighted fat-suppressed imaging pre- and post-intravenous gadolinium chelate administration (all patients) and breathing-independent single-shot T2-weighted half Fourier turbo (fast) spin echo (6 patients). Patients with pelvic abscesses also underwent sagittal imaging with post-gadolinium T1-weighted images (9 patients) and T2-weighted turbo (fast) spin echo (8 patients). Abscesses were confirmed by open surgery or surgical drainage (6 patients), percutaneous drainage (8 patients), or combined physical examination, fluoroscopic fistulogram, and clinical follow-up (2 patients). Oval-shaped fluid collections were identified in all of the patients, which ranged in diameter from 2 cm to 18 cm, mean: 8 cm. Abscesses were low to intermediate in signal on T1-weighted images, heterogenous and moderately high signal on T2-weighted images, and low signal on post-gadolinium images. A layering effect of lower signal material in the dependent portion of the abscess was noted in abscesses in 6 of 14 patients on T2-weighted images. Post-gadolinium images demonstrated a definable 3- to 7-mm thick abscess wall, which enhanced substantially with contrast. Definition of the wall was best shown on fat-suppressed images post-gadolinium. Substantial enhancement of surrounding periabscess tissues was demonstrated in all cases and was most clearly defined on fat-suppressed images. Image acquisition in two orthogonal planes was of value to demonstrate that fluid collections were oval, and separate from bowel. Image acquisition in the sagittal plane was useful in the evaluation of pelvic abscesses. The results from this preliminary study show that bowel-related abscesses are demonstrable on MR images using gadolinium-enhanced fat-suppressed T1-weighted and turbo (fast) spin-echo T2-weighted sequences. The presence of a thickened, enhancing lesion wall and enhancement of perilesional tissues on T1-weighted fat-suppressed images were observed in all abscesses. A layering effect of low signal intensity material in the dependent portion of the abscess was an important ancillary feature.

Asunto(s)

Absceso/diagnóstico , Enfermedades Intestinales/diagnóstico , Imagen por Resonancia Magnética , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Masculino , Persona de Mediana Edad , Pelvis

RESUMEN

PURPOSE: The goal of our study was to examine the prevalence of multiple hypodense splenic nodules and their associated diagnoses and to correlate CT appearance with clinical presentation and diagnosis. METHOD: Records of all patients undergoing contrast-enhanced CT from July 1994 through September 1997 were reviewed. Charts and CT scans of patients with multiple (more than five) hypodense splenic nodules were then evaluated. RESULTS: During the search period, there were 8,764 patients examined. Multiple hypodense splenic nodules were identified in 45 patients. Sixteen patients had malignant neoplasia as an etiology, with two patients having a benign tumor. Ten patients had an infectious etiology; nine patients had an inflammatory but noninfectious etiology; in eight patients, a diagnosis was not established; five of these patients were followed for > 18 months. CONCLUSION: Multiple hypodense splenic nodules are uncommon. Lymphoma, infection, and sarcoid were the three most common disorders in the symptomatic patient, with infection strongly correlated with a compromised immune system. In the asymptomatic patient, nonlymphomatous metastatic disease, benign tumor, and sarcoid were most common. Although overlap exists between diagnostic groups, lymphoma tends to have larger, more variable nodules, whereas infection tends to occur with smaller, more uniform nodules. Sarcoid is intermediate in appearance.

Asunto(s)

Bazo/diagnóstico por imagen , Enfermedades del Bazo/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Medios de Contraste/administración & dosificación , Diagnóstico Diferencial , Femenino , Humanos , Inyecciones Intravenosas , Hígado/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Esplenomegalia/diagnóstico por imagen , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/métodos

RESUMEN

Hepatosplenic candidiasis (HSC) is a morbid complication encountered in immunocompromised individuals, especially, those being treated with intensive chemotherapy protocols for acute leukemia. Immediate recognition of this complication and initiation of appropriate treatment is crucial in order to control the infection, decrease the morbidity and mortality, and avoid delays in treatment of the underlying condition. The definitive diagnosis requires either positive blood cultures for yeasts in the presence of abnormal findings on imaging studies consistent with HSC, or liver biopsy demonstrating yeast forms or pseudohyphae. We describe our experience in the evaluation of 15 patients with HSC using magnetic resonance imaging (MRI) as a diagnostic and follow-up tool. The diagnosis of HSC was established by liver biopsy in 11 patients (73%), and by positive blood cultures for Candida in 4 patients (27%). All patients had MRI findings consistent with HSC during the study period. Amphotericin B was administered intravenously to all 15 patients (median duration of treatment, 62 days). Repeat MR images were obtained at 2 weeks, 6 weeks and then at monthly intervals until the resolution of abnormalities. The median time for the disappearance of MRI lesions was 9 weeks. Alterations in the appearance of lesions on MRI were noted throughout chemotherapy in all the 13 (86.6%) responding patients. Our results suggest that MRI when used in patients with high clinical suspicion for HSC provide an alternative for liver biopsy or other invasive diagnostic procedures and that appropriate response to treatment can be safely monitored by obtaining sequential MRI studies.

Asunto(s)

Candidiasis/diagnóstico , Leucemia Mieloide Aguda/complicaciones , Hepatopatías/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicaciones , Enfermedades del Bazo/diagnóstico , Adolescente , Adulto , Anciano , Candidiasis/complicaciones , Candidiasis/tratamiento farmacológico , Niño , Humanos , Hepatopatías/complicaciones , Hepatopatías/tratamiento farmacológico , Imagen por Resonancia Magnética , Persona de Mediana Edad , Enfermedades del Bazo/complicaciones , Enfermedades del Bazo/tratamiento farmacológico , Resultado del Tratamiento

RESUMEN

PURPOSE: To prospectively investigate the diagnostic accuracy of and appearances at magnetic resonance (MR) imaging of patients clinically suspected to have intraperitoneal abscesses. MATERIALS AND METHODS: Sixty-seven consecutive patients underwent MR imaging for suspected intraperitoneal abscesses. MR images were prospectively interpreted for intraperitoneal abscesses; the results were correlated with surgical, histopathologic, and laboratory findings. RESULTS: MR imaging revealed 25 fluid collections consistent with intraperitoneal abscesses in 22 of 67 patients (33%). Of these collections, 22 were intraperitoneal abscesses; one, a giant sigmoid diverticulum; and two, sterile fluid collections. The latter two patients had been receiving antibiotic therapy. MR imaging allowed exclusion of intraperitoneal abscesses in 45 patients (67%). All collections demonstrated decreased signal intensity on T1-weighted images; on T2-weighted images, 13 collections demonstrated homogeneously increased signal intensity and 12 demonstrated heterogeneously increased signal intensity. The abscesses were best demonstrated on gadolinium-enhanced T1-weighted fat-suppressed images as well-defined fluid collections with peripheral rim enhancement. Sensitivity was 100%; specificity, 94% (95% confidence interval = 83%, 99%); positive predictive value, 88% (95% confidence interval = 69%, 97%); negative predictive value, 100%; and accuracy, 96% (95% confidence interval = 88%, 99%). CONCLUSION: MR imaging has high diagnostic accuracy in evaluation of acute intraperitoneal abscesses.

Asunto(s)

Absceso Abdominal/diagnóstico , Imagen por Resonancia Magnética , Enfermedades Peritoneales/diagnóstico , Absceso Abdominal/etiología , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Peritoneales/etiología , Sensibilidad y Especificidad

RESUMEN

This study describes the sequential use of ferumoxide (superparamagnetic iron oxide) particles and nonspecific extracellular gadolinium chelate (Gd) for evaluation of focal liver lesions on MRI to evaluate order of contrast administration and imaging effect of the first contrast agent on sequences acquired after the second contrast agent. Thirteen patients underwent MR examinations that included ferumoxide and Gd. The order and timing of administration were as follows: separate sessions (three patients; Gd study 4-19 days before ferumoxide study), same session, Gd first (seven patients; Gd study 1-2 hours before ferumoxide study), and same session, ferumoxide first (three patients; ferumoxide administered less than 1 hour before Gd study). Postcontrast sequences were reviewed in a randomized, blinded fashion by two separate investigators. Determination was made regarding whether (a) the presence of the first agent administered could be detected on sequences obtained after the second agent and (b) the presence of the first agent interfered with the image quality of those sequences. No evidence for the presence of Gd was appreciated by either observer on postferumoxide sequences acquired in separate session studies. In same session, Gd first studies, the presence of Gd was observed in six of seven patients on T1-weighted spoiled gradient-echo (SGE) images obtained after ferumoxide administration. The presence of Gd was not apparent in seven of seven patients on T2-weighted fat-suppressed images obtained after ferumoxide. In same session, ferumoxide first studies, the presence of ferumoxide was appreciated on post-Gd sequences in two of three patients. The presence of ferumoxide did not appreciably diminish image quality on those sequences. Exact agreement was achieved by the independent investigators. Our results suggest that Gd and ferumoxide can be administered sequentially within one study session without substantial loss of diagnostic information obtained on sequences performed after administration of the second contrast agent. Administrating Gd first resulted in less of an effect of the visualization of the first agent on sequences acquired after the second agent.

Asunto(s)

Medios de Contraste , Gadolinio DTPA , Hierro , Neoplasias Hepáticas/diagnóstico , Imagen por Resonancia Magnética , Óxidos , Adulto , Anciano , Medios de Contraste/administración & dosificación , Dextranos , Método Doble Ciego , Esquema de Medicación , Femenino , Óxido Ferrosoférrico , Gadolinio DTPA/administración & dosificación , Humanos , Aumento de la Imagen , Hierro/administración & dosificación , Hígado/patología , Neoplasias Hepáticas/secundario , Nanopartículas de Magnetita , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Óxidos/administración & dosificación , Sensibilidad y Especificidad

RESUMEN

OBJECTIVE: The purpose of this study was to define the common appearances of hepatocellular carcinoma (HCC) in patients in North America by analyzing T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images interpreted by radiologists at multiple institutions in North America. MATERIALS AND METHODS: One hundred thirteen consecutive patients with HCC from eight institutions were included in this retrospective case series. Inclusion criteria included MR imaging examinations performed on 1.5-T MR imagers using T1-weighted breath-hold spoiled gradient-echo images, T2-weighted images, and serial gadolinium-enhanced spoiled gradient-echo images. Diagnosis was established by histology in all patients. Images were analyzed retrospectively for lesion count, lesion diameter as less than or equal to 1.5 cm and greater than 1.5 cm, and signal intensity, by individual experienced radiologists at each institution. RESULTS: We found 354 HCC lesions in the 113 patients. Tumors were solitary in 63 patients, multifocal in 45 patients, and diffuse in five patients. Lesion appearance on combined T1-weighted, T2-weighted, and immediate gadolinium-enhanced spoiled gradient-echo images was as follows: 102 lesions (29%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse heterogeneous enhancement; 52 lesions (15%) were isointense on both T1- and T2-weighted images and exhibited diffuse homogeneous enhancement (all of these lesions measured < or = 1.5 cm in diameter); 50 lesions (14%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse homogeneous enhancement; 33 lesions (9%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited predominantly peripheral rim enhancement; and 27 lesions (8%) were hypointense on T1-weighted images, were isointense on T2-weighted images, and exhibited diffuse homogeneous enhancement. The remaining 90 lesions showed less common patterns. The appearance of HCCs greater than 1.5 cm and of HCCs less than or equal to 1.5 cm was significantly different (p = .001). The appearance of histologically proven HCCs is separately described. CONCLUSION: The combination of hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and diffuse heterogeneous enhancement was the most common appearance of HCC on MR images in a multiinstitutional patient population in North America. Small HCCs measuring less than or equal to 1.5 cm were frequently isointense on both T1-weighted and T2-weighted images and may be detected on immediate gadolinium-enhanced images only as diffuse homogeneously enhancing lesions.

Asunto(s)

Carcinoma Hepatocelular/diagnóstico , Medios de Contraste , Gadolinio DTPA , Neoplasias Hepáticas/diagnóstico , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Estados Unidos

RESUMEN

This study describes the MR appearances of malignant hypervascular liver lesions pre- and post-hepatic-arterial chemoembolization, with correlation to serial imaging and clinical responses. Eight patients with malignant hypervascular liver lesions underwent pretreatment and posttreatment MR examination on a 1.5-T MR imager. MR sequences included T1-weighted spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo or turbo spin echo, and dynamic gadolinium-enhanced SGE images. All patients underwent pretreatment, initial posttreatment, and subsequent posttreatment MR studies. The histology of primary tumors included various types of hepatocellular carcinoma (HCC) (four patients: fibrolamellar HCC [one patient], HCC [two patients], mixed HCC/cholangiocarcinoma [one patient]) and liver metastases (four patients: untyped islet cell tumor [two patients], gastrinoma [one patient], carcinoid [one patient]). Response to chemoembolization was determined by three assessments: MR response, serial imaging response, and clinical response. The appearance of MR response to chemoembolization was determined based on the correlation with clinical and serial imaging response. The MR response of lesions that showed good clinical response included: increase in signal intensity on T1-weighted images (three patients), decrease in signal intensity on T2-weighted images (three patients), and negligible or minimal enhancement on immediate postgadolinium images (four patients) after chemoembolization. The most marked change in lesion appearance was observed in lesions < or = 1 cm, which had intense homogeneous enhancement on pretreatment MR studies and negligible enhancement on initial posttreatment MR examinations. MR response of lesions that showed moderate clinical response demonstrated a variety of lesion appearances from substantial change to minimal change. MR response of lesions that showed poor clinical response demonstrated no change in lesion appearances compared with the pretreatment MR study. Our results demonstrated change in appearance of liver lesions between pre- and post-hepatic-arterial chemoembolization MR studies. MR response correlated with response determined by serial imaging studies and clinical findings.

Asunto(s)

Carcinoma Hepatocelular/terapia , Quimioembolización Terapéutica , Neoplasias Hepáticas/terapia , Hígado/patología , Imagen por Resonancia Magnética , Adolescente , Carcinoma Hepatocelular/patología , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/secundario , Masculino , Persona de Mediana Edad

RESUMEN

PURPOSE: To evaluate the normal appearance of fetal anatomy, the conspicuity of fetal organs, the reproducibility of images, and the limitations to image quality with the use of half-Fourier, single-shot rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fifty-four fetuses of 49 pregnancies underwent MR imaging with the half-Fourier, single-shot RARE technique. Two reviewers attempted to identify 47 organs and anatomic regions in each fetus. Organ or region conspicuity, image quality, and the limitations of image quality were graded. RESULTS: Fetal anatomy was well depicted in fetuses over 20 weeks in gestational age. Fetal imaging was limited by gestational age of 20 weeks or less usually owing to the small size of the organ or region being evaluated and, less frequently, by motion. CONCLUSION: Half-Fourier, single-shot RARE MR imaging provided a detailed and reproducible evaluation of normal fetal anatomy, which can be used as a standard of reference in MR imaging of fetal anomalies.

Asunto(s)

Feto/anatomía & histología , Imagen por Resonancia Magnética/métodos , Artefactos , Femenino , Movimiento Fetal , Análisis de Fourier , Edad Gestacional , Humanos , Embarazo , Valores de Referencia , Reproducibilidad de los Resultados , Procesamiento de Señales Asistido por Computador

RESUMEN

This study compares liver lesion detection, characterization, and effect on patient management between single-phase spiral CT and MRI using spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo, and serial post gadolinium SGE. All patients with suspected liver lesions who underwent spiral CT and MRI within a 1-month period between January 1993 and September 1996 were included in the study. Spiral CT and MRI were interpreted prospectively in a blinded fashion by separate individual experienced investigators, and lesion detection and characterization were determined. Confirmation was obtained by surgery (6 patients), biopsy (18 patients), imaging follow-up (36 patients), or combined reading of all imaging studies and clinical follow-up (29 patients). Effect on patient management was determined by combined chart review and interview of the patients' physicians and by retrospective clinical assessment performed by a surgical oncologist and medical oncologist separately. Eighty-nine patients were included in the study. Regarding true positive lesion detection, 295 and 519 lesions were detected on spiral CT and MR images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were detected on MR than on spiral CT in 44 of 89 patients (49.4%), and 11 of these 44 patients had lesions shown on MRI in whom no lesions were apparent on CT images. No patients had true positive lesions shown on spiral CT that were not shown on MRI. Regarding lesion characterization, 129 and 466 lesions were characterized on spiral CT and MRI images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were characterized on MR than CT images in 67 patients (75.3%). Regarding effect on patient management, chart review with physician interview demonstrated that findings on MRI provided information that altered patient management as compared with findings on spiral CT in 57 patients. Retrospective clinical evaluation by the surgical and medical oncologist showed that MRI was considered to have a greater effect on patient management than spiral CT in 58 and 55 patients, respectively. Comparing current MRI technique to single-phase spiral CT, MRI detected more lesions in 49.4% and characterized more lesions in 75.3% of patients investigated for focal liver disease. MRI had a greater effect on patient management in each of the three methods than single-phase spiral CT in more than 61% of patients.

Asunto(s)

Neoplasias Hepáticas/diagnóstico , Imagen por Resonancia Magnética , Planificación de Atención al Paciente , Tomografía Computarizada por Rayos X , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Interpretación Estadística de Datos , Femenino , Humanos , Masculino , Persona de Mediana Edad

Asunto(s)

Anticonvulsivantes/efectos adversos , Hipersensibilidad a las Drogas/complicaciones , Fenitoína/efectos adversos , Enfermedades del Bazo/inducido químicamente , Adulto , Humanos , Masculino , Enfermedades del Bazo/diagnóstico por imagen , Tomografía Computarizada por Rayos X

RESUMEN

PURPOSE: To establish the appearance of the normal placenta on dynamic, gadolinium-enhanced magnetic resonance (MR) images. MATERIALS AND METHODS: Eleven patients underwent MR imaging for suspected uterine (four patients) or placental (seven patients) abnormalities (but not placental insufficiency or intrauterine growth retardation). Unenhanced or gadolinium-enhanced, T1-weighted, fat suppressed, spoiled gradient-recalled-echo MR images and T2-weighted, half-Fourier, single-shot, spin-echo-train MR images were obtained. Two investigators retrospectively evaluated the images to determine the rate, pattern, and degree of placental contrast material enhancement with myometrial enhancement as a reference. RESULTS: The diagnoses were normal placenta (six patients), abnormal placental position (four patients), and subchorionic hematoma (one patient). The placenta rapidly and intensely enhanced on images acquired immediately after contrast material administration and preceded substantial enhancement of the myometrium. Immediately postcontrast images showed closely packed 2-3-cm lobules of placental enhancement in third-trimester pregnancies and heterogeneous placental enhancement in second-trimester pregnancies. In all cases, placental enhancement became more homogeneous over time. The placenta could be readily distinguished from the myometrium. All neonates were healthy with no evidence of intrauterine growth retardation. CONCLUSION: Normal placental enhancement is intense on immediately postcontrast images and precedes substantial myometrial enhancement. Third-trimester placentas exhibit a lobular pattern of enhancement, while second-trimester placentas exhibit heterogeneous enhancement.

Asunto(s)

Imagen por Resonancia Magnética , Placenta/anatomía & histología , Adulto , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Recién Nacido , Placenta/patología , Enfermedades Placentarias/diagnóstico , Embarazo , Trimestres del Embarazo , Valores de Referencia

RESUMEN

OBJECTIVE: We describe our 6-year experience in the prospective examination of patients with suspected hepatosplenic fungal disease to show the diagnostic accuracy of MR imaging and the spectrum of appearances on MR images. SUBJECTS AND METHODS: All patients who underwent MR examination for suspected hepatosplenic fungal disease from January 1990 to January 1997 in three university institutions were included in the study. Patients presented with persistent fever or no response to antibacterial antibiotics. Patients were grouped as acute, subacute treated, and chronic treated, according to the duration of their symptoms. Patients with 2 weeks or fewer of possible infection were acute presentation, patients on antifungal therapy longer than 2 weeks but shorter than 3 months were subacute treated presentation, and patients on antifungal therapy for 3 months or longer or who had completed antifungal therapy and had a history of hepatosplenic fungal disease were chronic treated presentation. MR studies were prospectively interpreted for the presence of hepatosplenic fungal lesions. The appearances of fungal lesions in patients in each category were determined. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detecting lesions in patients with acute presentation were also determined. RESULTS: Sixty-nine patients were included in the study. MR imaging revealed signs consistent with hepatosplenic fungal lesions in 22 (32%) of 69 patients and no demonstration of hepatosplenic lesions in 47 (68%) of 69 patients. In the 60 patients with acute presentation, MR imaging in 13 patients revealed hepatosplenic lesions that were interpreted as fungal disease. True-positive lesions were present in 11 of these 13 patients. These lesions measured less than 1 cm in diameter and were best shown as well-defined high-signal-intensity foci on T2-weighted images. The remaining two of the 13 patients had false-positive lesions; one was shown to have tuberculosis, and the other had graft-versus-host disease. For acute presentation, MR sensitivity was 100%, specificity was 96%, positive predictive value was 85%, negative predictive value was 100%, and accuracy was 97%. In the five patients with subacute presentation, lesions were present that measured less than 1 cm in diameter and were best shown as mildly hyperintense on T1-weighted images. A perilesional ring nearly void of signal intensity was seen on unenhanced and gadolinium-enhanced T1-weighted images in all five patients. The four patients with chronic healed lesions all had lesions that were 1-3 cm in diameter with irregular, angular polygonal margins. These lesions, which were best shown on images obtained immediately after gadolinium administration, appeared as regions of diminished enhancement with no perilesional changes. CONCLUSION: MR imaging has high diagnostic accuracy for the diagnosis of acute hepatosplenic fungal disease. Patients with acute, subacute treated, and chronic healed presentations may have lesions that can be distinguished by their MR appearances.

Asunto(s)

Candidiasis/diagnóstico , Hepatopatías/microbiología , Imagen por Resonancia Magnética , Enfermedades del Bazo/microbiología , Enfermedad Aguda , Adulto , Candidiasis/inmunología , Enfermedad Crónica , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Huésped Inmunocomprometido , Hepatopatías/diagnóstico , Hepatopatías/inmunología , Masculino , Neutropenia/inmunología , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , Enfermedades del Bazo/diagnóstico , Enfermedades del Bazo/inmunología

RESUMEN

We describe magnetic resonance findings in three patients with small bowel intussusception from different etiologies including idiopathic, adenomatous polyps, and hamartomatous polyps. Magnetic resonance findings showed a bowel-within-bowel appearance in two patients and a coiled-spring appearance in one patient. These findings were best shown on T2-weighted images, and clear definition was present on breathing independent T2-weighted images using half fourier acquisition snap shot turbo spin echo T2-weighted images.

Asunto(s)

Enfermedades del Íleon/diagnóstico , Intususcepción/diagnóstico , Enfermedades del Yeyuno/diagnóstico , Imagen por Resonancia Magnética/métodos , Adulto , Humanos , Enfermedades del Íleon/etiología , Enfermedades del Íleon/cirugía , Intususcepción/etiología , Intususcepción/cirugía , Enfermedades del Yeyuno/etiología , Enfermedades del Yeyuno/cirugía , Masculino , Persona de Mediana Edad , Síndrome de Peutz-Jeghers/complicaciones