MR imaging of white matter disease in children

Twenty-three pediatric patients with white matter abnormalities on MR images were evaluated retrospectively to assess the contribution of MR compared with CT in diagnosing these conditions. In addition, the MR findings in major categories of white matter diseases were analyzed for sensitivity in detecting the presence of an abnormality. White matter disease categories included demyelinating disease (five cases), dysmyelinating disease (eight cases), developmental white matter abnormalities (four cases), and white matter abnormalities of unknown origin (idiopathic) (six cases), as seen on long TR images. We found that MR is not more sensitive than CT in detecting disease in the demyelinating or dysmyelinating categories, although it is more sensitive than CT in detecting the degree of disease present. In cases of developmental delay, MR is distinctly more useful than CT in demonstrating abnormalities of myelination. And in the idiopathic group, MR detected the presence of focal white matter abnormalities on long TR images in children with neurologic complaints and normal CT. MR may serve to redefine and broaden the spectrum of reported imaging abnormalities in pediatric patients.     

Magnetic resonance imaging findings in diffuse lymphangiomatosis: neuroradiological manifestations

We report magnetic resonance (MR) findings in a patient with histologically proven lymphangiomatosis with a history of chylothorax, diffuse lung infiltrates, spinal involvement, cystic lesions of the mediastinum, and mesentery thickening. The patient also had diffuse infiltration of the right brachial plexus, with similar imaging findings as the spinal lesions. Although osseous and extraosseous involvement may be seen frequently with lymphangiomatosis, involvement of the brachial plexus has not been previously reported.     

Imaging of degenerative brain disorders

Recent advances have been made in defining the imaging findings associated with degenerative brain disorders, especially Alzheimer's disease, multi-infarct dementia, and multiple sclerosis. CT and MR imaging are capable of evaluating structural changes seen in these abnormalities. Positron emission tomography and single-photon emission CT studies, by evaluating metabolic changes, may demonstrate abnormalities before those seen on CT or MR imaging. Recent articles pertaining to the imaging of degenerative brain disorders are reviewed and discussed.     

Renal peripelvic lymphatic cysts (lymphangiomas) associated with generalized lymphangiomatosis.

Renal peripelvic lymphatic cysts (lymphangiomas) are usually seen as an isolated finding. They appear as multiple mass lesions with low attenuation on computed tomography (CT), and show no contrast enhancement. We present a case of renal peripelvic lymphatic cysts associated with generalized lymphangiomatosis, and examined with magnetic resonance imaging (MRI), CT, and lymphangiography. Multiplanar MRI demonstrated the extent of disease, including retroperitoneal lesions. The lesions had low-signal intensity on T1-weighted and high-signal intensity on T2-weighted images. The diagnosis of generalized lymphangiomatosis was verified by renal sinus cyst puncture, lymphangiography, and tissue biopsy.     

Renal peripelvic lymphatic cysts (lymphangiomas) associated with generalized lymphangiomatosis

Renal peripelvic lymphatic cysts (lymphangiomas) are usually seen as an isolated finding. They appear as multiple mass lesions with low attenuation on computed tomography (CT), and show no contiast enhancement. We present a case of renal peripelvic lymphatic cysts associated with generalized lymphangiomatosis, and examined with magnetic resonance imaging (MRI), CT, and lymphangiography. Multiplanar MRI demonstrated the extent of disease, including retroperitoneal lesions. The lesions had low-signal intensity on T1-weighted and high-signal intensity on T2-weighted images. The diagnosis of generalized lymphangiomatosis was verified by renal sinus cyst puncture, lymphangiography, and tissue biopsy.     

CT features of generalized lymphangiomatosis in adult patients

ObjectiveThe objective was to present computed tomographic (CT) findings of generalized lymphangiomatosis in young adults that was at first misdiagnosed with malignancy.Materials and methodsWe reviewed the clinical and radiological findings of three young adults who had histologically confirmed generalized lymphangiomatosis.ResultsBony lesions were cystic forms and appeared as variably sized, well-circumscribed, irregular, microlobulated-contour, multiseptated masses. Lymphangiomas involving soft tissue were similar to bony lesions on CT.ConclusionCT features of generalized lymphangiomatosis may be useful to prevent invasive procedures in young subjects. Generalized lymphangiomatosis involving bones in young adults shows less extensive and aggressive osteolytic pattern than known features in child.     

骨内腱鞘囊肿的影像学表现

目的:探讨骨内腱鞘囊肿的影像学表现及诊断与鉴别诊断.方法:回顾性分析经手术证实的20例骨内腱鞘囊肿的临床及影像资料,均行X线、CT检查,2例行MRI检查.结果:X线、CT表现为邻近关节面的类圆形囊样透亮区,边界清晰,18例有完整硬化边,10例病灶内见粗细不均的条状骨性间隔,3个病灶通过裂隙与关节腔相通,CT值20～60 HU,MRI在T2WI和脂肪抑制序列均表现为高信号.结论:骨内腱鞘囊肿的X线、CT典型表现为骨内邻近关节面的囊状破坏,边界清晰硬化,MRI在T2WI和脂肪抑制序列均表现为高信号,结合发病部位和临床症状及影像学表现,对本病可作出正确诊断.     

Correlation of early dynamic CT perfusion imaging with whole-brain MR diffusion and perfusion imaging in acute hemispheric stroke

BACKGROUND AND PURPOSE: Compared with MR imaging, dynamic CT perfusion imaging covers only a fraction of the whole brain. An important assumption is that CT perfusion abnormalities correlate with total ischemic volume. The purpose of our study was to measure the degree of correlation between abnormalities seen on CT perfusion scans and the volumes of abnormality seen on MR diffusion and perfusion images in patients with acute large-vessel stroke. METHODS: Fourteen patients with acute hemispheric stroke symptoms less than 12 hours in duration were studied with single-slice CT perfusion imaging and multislice MR diffusion and perfusion imaging. CT and MR perfusion studies were completed within 2.5 hours of one another (mean, 77 minutes) and were reviewed independently by two neuroradiologists. Hemodynamic parameters included cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Extents of abnormality on images were compared by using Kendall correlation. RESULTS: Statistically significant correlation was found between CT-CBF and MR-CBF abnormalities (tau = 0.60, P =.003) and CT-MTT and MR-MTT abnormalities (tau = 0.65, P =.001). Correlation of CT-CBV with MR-CBV approached significance (tau = 0.39, P =.06). Extent of initial hyperintensity on diffusion-weighted images correlated best with extent of MR-CBV abnormality (tau = 0.69, P =.001), extent of MR-MTT abnormality (tau = 0.67, P =.002), and extent of CT-CBV abnormality (tau = 0.47, P =.02). CONCLUSION: Good correlation was seen between CT and MR for CBF and MTT abnormalities. It remains uncertain whether CT perfusion CBV abnormalities correspond well to whole-brain abnormalities.     

Metastatic liver tumor from cystic ovarian carcinomas: CT and MRI appearance.

OBJECTIVE: The initial and follow-up CT and MRI images of ten patients with hepatic metastases from ovarian tumors were retrospectively analyzed to establish their features and sequential changes in appearance. MATERIALS AND METHODS: Ten patients with hepatic metastasis from ovarian tumors received initial and follow-up CT and MRI examinations. Six patients were followed up every two to three weeks before surgical tumor resection. Both CT and MR images were analyzed by two radiologists. RESULTS: A total of fourteen lesions were detected by CT and MRI in 10 patients. All 14 lesions were demonstrated as areas of marked hyperintensity on T2-weighted MRI. Eleven cyst-like tumors were demonstrated as round or oval low density lesions on CT and as areas of hypointensity on T1-weighted imaging. Three lesions were shown as solid masses with slightly low attenuation at the initial CT examination and slightly low or iso-intensity areas on T1-weighted imaging, and these lesions showed early peripheral globular enhancement and delayed enhancement on contrast-enhanced CT and MR imaging. Cystic formation was observed two to three weeks later after initial study in all the 3 solid lesions. Rapid subcapsular effusion, which showed obvious enhancement on delayed Gd-DTPA enhanced MR imaging, was observed in two patients. CONCLUSION: The hepatic metastatic tumor from cystic ovarian carcinoma may manifest as a well-defined cystic lesion or as a solid mass, and the solid mass shows delayed enhancement on contrast-enhanced CT and MR imaging. Furthermore, rapid cystic formation and rapid subcapsular extension is frequently seen.     

CNS complications of AIDS: CT and MR findings

AIDS is now a common disease, seen daily in large metropolitan medical centers. Neuroimaging techniques such as CT and MR are critical to the detection and diagnosis of CNS complications. Intracerebral infections are common. These infections frequently are caused by opportunistic organisms; less commonly, they are bacterial infections. The cranial imaging features on CT and MR are not pathognomonic, but their distribution or appearance (e.g., asymmetric target lesions of toxoplasmosis) may have predictive value in a known AIDS patient. The superior contrast resolution of MR makes it a more sensitive cross-sectional imaging tool for evaluating intracerebral abnormalities associated with a variety of infectious processes. Differential diagnoses still include metastatic disease, lymphoma, and infarcts. When MR is used as the initial cross-sectional imaging study, contrast-enhanced CT may still be necessary to further characterize a lesion. Currently, more experience exists with CT for follow-up of the AIDS patient with CNS manifestations. MR, particularly with gadolinium-DTPA as a contrast medium, will probably become the imaging method of choice.     

Hydatid disease: radiologic and pathologic features and complications.

Hydatid disease primarily affects the liver and typically demonstrates characteristic imaging findings. However, there are many potential local complications (eg, intrahepatic complications, exophytic growth, transdiaphragmatic thoracic involvement, perforation into hollow viscera, peritoneal seeding, biliary communication, portal vein involvement, abdominal wall invasion). Furthermore, secondary involvement due to hematogenous dissemination may be seen in almost any anatomic location (eg, lung, kidney, spleen, bone, brain). Ultrasonography (US) is particularly useful for the detection of cystic membranes, septa, and hydatid sand. Computed tomography (CT) best demonstrates cyst wall calcification and cyst infection. CT and magnetic resonance (MR) imaging may demonstrate cyst wall defects as well as the passage of contents through a defect. Chest radiography, US, CT, and MR imaging are all useful in depicting transdiaphragmatic migration of hydatid disease. CT is the modality of choice in peritoneal seeding. US and CT demonstrate rupture in most cases that involve wide communication. Indirect signs of biliary communication include increased echogenicity at US and fluid levels and signal intensity changes at MR imaging. CT allows precise assessment of osseous lesions, whereas MR imaging is superior in demonstrating neural involvement. Familiarity with atypical manifestations of hydatid disease may be helpful in making a prompt, accurate diagnosis.     

肝脏囊性转移瘤的CT和MR征象的比较

目的:分析肝脏囊性转移瘤在CT和MR上的表现,比较CT和MR检查对囊性转移瘤的临床诊断价值.材料和方法:18例(共52个病灶)肝脏囊性转移瘤中10例行CT平扫和增强门脉期扫描.8例行MR T1WI和FMP-SPGR多期动态增强扫描.观察肿瘤的大小、形态、数目、囊壁和壁结节的强化情况.结果:2例为单发病灶外,其余均为多发病灶.病灶呈类圆形或椭圆形.CT上8例见到囊壁不规则增厚,其中6例可见向囊腔内突起的壁结节,1例内有分隔.2例薄壁且均匀的病灶误诊为肝囊肿.T1WI上,7例为低信号,1例为混杂信号.T2WI上,病灶均为明显高信号,2例信号均匀,6例信号不均匀,可见到壁结节为略低信号.增强动脉期所有病灶均无强化表现,门脉期和延迟期,可见到边缘环形强化和壁结节的强化.也有1例见到分隔.结论:CT和MR均可显示肝脏囊性转移瘤的特征,MR在显示病灶的出血、囊变、分隔和囊壁的情况等比CT更为敏感、可靠,在鉴别诊断方面价值更大.     

Cystic neoplasms of the pancreas: comparison of MR imaging with CT

Cystic neoplasms of the pancreas are divided into two major groups: microcystic adenomas and mucinous cystic neoplasms. Five microcystic adenomas and seven mucinous cystic neoplasms (three cystadenomas and four cystadenocarcinomas) were examined with both magnetic resonance (MR) imaging and computed tomography (CT). The cystic content was differentiated more easily with MR imaging than with CT. It was homogeneous in four of the five microcystic adenomas, all of which had lobulated borders best seen on T2-weighted images. The mucinous cystadenomas and cystadenocarcinomas were all composed of multiple compartments that varied in signal intensity. The septa, shape, and wall thickness were demonstrated on T1- and/or T2-weighted MR images almost as well as on CT scans. Overall, MR imaging was equal or slightly superior to CT in the diagnosis of pancreatic cystic neoplasms, except in its limited ability to demonstrate calcifications of the tumor wall and septa.     

Myxoid liposarcoma: appearance at MR imaging with histologic correlation.

Although myxoid liposarcoma is a subtype of liposarcoma, it may be difficult to establish the correct diagnosis with magnetic resonance (MR) imaging due to the lack of fat signal intensity. Without the administration of gadolinium contrast material, the tumor may even mimic a cystic tumor. A spectrum of MR imaging abnormalities occur in myxoid liposarcoma, depending on the amount of fat and myxoid material, the degree of cellularity and vascularity, and the presence of necrosis. Most myxoid liposarcomas have lacy or linear, amorphous foci of fat. Some myxoid liposarcomas appear to be cystic at nonenhanced MR imaging, although they enhance like other solid masses at contrast material-enhanced MR imaging. The enhancing areas within the tumor represent increased cellularity and vascularity; the nonenhancing areas represent necrosis, reduced cellularity, and accumulated mucinous material. Gadolinium-enhanced imaging is important in differentiating myxoid liposarcoma from benign cystic tumors. Characterization of the tumor with MR imaging plays an important role in the management of myxoid liposarcoma.     

Cystic focal liver lesions in the adult: differential CT and MR imaging features.

Cystic lesions of the liver in the adult can be classified as developmental, neoplastic, inflammatory, or miscellaneous. Although in some cases it is difficult to distinguish these entities with imaging criteria alone, certain cystic focal liver lesions have classic computed tomographic (CT) and magnetic resonance (MR) imaging features, which are important for the radiologist to understand and recognize. Lesions with such features include simple (bile duct) cyst, autosomal dominant polycystic liver disease, biliary hamartoma, Caroli disease, undifferentiated (embryonal) sarcoma, biliary cystadenoma and cystadenocarcinoma, cystic subtypes of primary liver neoplasms, cystic metastases, pyogenic and amebic abscesses, intrahepatic hydatid cyst, extrapancreatic pseudocyst, and intrahepatic hematoma and biloma. Specific CT and MR imaging findings that are important to recognize are the size of the lesion; the presence and thickness of a wall; the presence of septa, calcifications, or internal nodules; the enhancement pattern; the MR cholangiographic appearance; and the signal intensity spectrum. In addition, access to critical clinical information remains extremely important. The most important clinical parameters defined include age and gender, clinical history, and symptoms. An understanding of the classic CT and MR imaging appearances of cystic focal liver lesions will allow more definitive diagnosis and shorten the diagnostic work-up.     

Imaging of the peritoneal cavity

Newer techniques and applications of cross-sectional imaging of the abdomen with CT, ultrasound, and MR imaging have facilitated the diagnosis of diseases primarily involving the peritoneal cavity. CT peritoneography may aid in diagnosing complications of peritoneal dialysis, and detecting internal hernias and small peritoneal implants. Uncommon abnormalities such as sclerosing encapsulating peritonitis, cystic mesothelioma, and peritonitis from rupture of a retroperitoneal teratoma may also be diagnosed with CT or ultrasonography.     

Wegener granulomatosis: CT and MR findings.

PURPOSETo demonstrate the spectrum of CT and MR imaging findings in patients with Wegener granulomatosis and to determine how often these findings could be attributed to either direct extension from paranasal or orbital disease sites, remote granulomas, or central nervous system (CNS) vasculitis.METHODSWe retrospectively reviewed the CT or MR studies of 15 patients with Wegener granulomatosis.RESULTSAbnormal findings were seen in 7 patients (5 examined with MR imaging, 2 with CT). Findings included dural thickening and contrast enhancement (3 patients), infarcts (2 patients), regions of hyperintense signal on T2-weighted MR images (2 patients), and abnormal MR signal in the brain stem (2 patients). Three patients with imaging findings of dural enhancement and thickening were thought to have remote granulomatous lesions involving the dura. No patients had extension from sites external to the CNS or clinical findings suggestive of CNS vasculitis.CONCLUSIONThe spectrum of CT and MR findings in Wegener granulomatosis includes dural thickening and enhancements cerebral infarction, and MR signal abnormalities in the brain stem and white matter. Presumed remote granulomatous lesions were the most common causes of CNS findings in this study. Complications related to non-CNS disease (eg, hypertension, endocarditis) also appear to have played a role in some patients.     

Seminal vesicle cyst with ipsilateral renal agenesis

OBJECTIVE: The purpose of this study was to review the clinical symptoms and imaging features of a seminal vesicle cyst associated with renal agenesis. CONCLUSION: Patients with seminal vesicle cysts associated with renal agenesis may present with symptoms of bladder irritation or obstruction and with an abdominal or pelvic mass revealed on physical examination. Differentiation of a seminal vesicle cyst from other pelvic cystic masses may be determined with a spectrum of imaging techniques including excretory urography, sonography, CT, and MR imaging.     

Comparison of MR imaging after barium administration with CT in pelvic disease.

The use of magnetic resonance (MR) imaging for evaluating the abdomen and pelvis has been limited by the lack of a suitable contrast agent. The purpose of this study was to compare axial MR imaging after rectal barium administration with computed tomography (CT) for delineation of normal anatomy and lesions of the pelvis. MR images and CT scans of 11 patients were studied retrospectively and independently by four radiologists. No substantial differences in the visualization of normal bowel, iliac vessels, lymph nodes, bladder, prostate, seminal vesicles, uterus, and cervix and in detection of abnormalities were seen between CT scans and axial MR images obtained after barium administration. This preliminary study suggests that axial MR imaging with rectal barium is a useful alternative to CT in evaluating pelvic disease.     

Imaging features of iliopsoas bursitis

The aim of this study was firstly to describe the spectrum of imaging findings seen in iliopsoas bursitis, and secondly to compare cross-sectional imaging techniques in the demonstration of the extent, size and appearance of the iliopsoas bursitis as referenced by surgery. Imaging studies of 18 patients (13 women, 5 men; mean age 53 years) with surgically proven iliopsoas bursitis were reviewed. All patients received conventional radiographs of the pelvis and hip, US and MR imaging of the hip. The CT was performed in 5 of the 18 patients. Ultrasound, CT and MR all demonstrated enlarged iliopsoas bursae. The bursal wall was thin and well defined in 83% and thickened in 17% of all cases. The two cases with septations on US were not seen by CT and MRI. A communication between the bursa and the hip joint was seen, and surgically verified, in all 18 patients by MR imaging, whereas US and CT failed to demonstrate it in 44 and 40% of the cases, respectively. Hip joint effusion was seen and verified by surgery in 16 patients by MRI, whereas CT (4 of 5) and US ( n=12) underestimated the number. The overall size of the bursa corresponded best between MRI and surgery, whereas CT and US tended to underestimate the size. Contrast enhancement of the bursal wall was seen in all cases. The imaging characteristics of iliopsoas bursitis are a well-defined, thin-walled cystic mass with a communication to the hip joint and peripheral contrast enhancement. The most accurate way to assess iliopsoas bursitis is with MR imaging; thus, it should be used for accurate therapy planning and follow-up studies. In order to initially prove an iliopsoas bursitis, US is the most cost-effective, easy-to-perform and fast alternative.