Seventeen years of prenatal magnetic resonance imaging at the Institute of Mother and Child in Warsaw.

PURPOSE: The purpose of this paper is to summarise and to present the experience of the main Polish centre for prenatal magnetic resonance imaging (MRI) and to discuss the place and role of MRI in antenatal diagnosis, management, and counselling. MATERIAL AND METHODS: Retrospective analysis of the examinations performed in the years 2001-2017. RESULTS: In total, 1221 medical records and/or image files were collected. The full documentation of ultrasonography and MRI referrals, reports, and images was not available in every case. During the first three years 98 pregnant women were examined (approximately 33 per year, one study per fortnight). After purchase of own MR scanner, the number of examinations grew constantly, reaching 208 in 2017, which means almost one per day, and the highest number was eight in one day. We examined 45 pairs of twins, including three pairs of conjoined twins. CONCLUSIONS: MRI at our Institute is a practically used second-line foetal imaging tool, necessary to confirm, complete, or correct sonographic diagnoses, with important impact on clinical decisions concerning management of pregnancy and of the neonate, termination of pregnancy, choice of the time, place, and mode of delivery, and neonatal care, as well as on counselling. In experienced hands, MRI is to date the last and the best non-invasive method of diagnosis in utero. It is frequently requested by the interdisciplinary team for foetal diagnosis and therapy and routinely performed in everyday practice.

Diagnostic Imaging of Pregnant Women - The Role of Magnetic Resonance Imaging.

BACKGROUND: Presentation of magnetic resonance imaging (MRI) findings in pregnant women in the Department of Diagnostic Imaging, Institute of Mother and Child, Warsaw, Poland. MATERIAL/METHODS: Forty-three symptomatic pregnant women underwent MRI between 9 and 33 weeks of gestation (mean of 23 weeks). Moreover, we included 2 pregnant women who underwent fetal MRI and had incidental abnormalities. RESULTS: In 9 cases, we excluded the suspected brain abnormalities. In 4 cases, we found unremarkable changes in the brain without clinical significance. One patient was diagnosed with multiple sclerosis, one with cortical dysplasia, one with pineal hemorrhage and one with a brain tumor. On abdominal MRI, 2 patients had normal findings, one patient had colon cancer with a hepatic metastasis, one patient had a hepatic angioma, one patient had an extraadrenal pheochromocytoma, one patient had an abscess in the iliopsoas muscle, 9 patients had myomas, two patients had ovarian simple cysts, two endometrial cysts, three dermoid cysts, one patient had sacrococcygeal teratoma, one patient had a cystadenofibroma (partial borderline tumor), one patient had an androgenic ovarian tumor and two patients had hyperreactio luteinalis. One patient was diagnosed with transient osteoporosis of the hip and one with a stress fracture of the sacral bone. CONCLUSIONS: Magnetic resonance imaging is the best imaging modality for pregnant women. Although ultrasonography is the method of choice, doubtful cases as well as structures that cannot be examined with ultrasonography can be non-invasively evaluated with MRI.

Fetal MRI versus postnatal imaging in the MR-compatible incubator.

INTRODUCTION: One of the aims of fetal magnetic resonance imaging (MRI) is to avoid postnatal scanning. However, clinicians sometimes wish to have postnatal confirmation of prenatal findings. This study's purpose was to check whether there was indeed the added value of neonatal MRI performed in the MR-compatible incubator (INC) after fetal examination. MATERIALS AND METHODS: Material consists of 25 neonates (14 girls) who underwent prenatal and postnatal MRI in a 1.5 T scanner, the latter in INC. Mean time of prenatal MRI was 30th gestational week, of postnatal MRI-16th day of life. RESULTS: In 14 cases (56 %) postnatal findings were the same as prenatal ones. In 11 (44 %) postnatal MRI showed some different/new/more precise results, in two the differences were attributed to other factors than the advantage of postnatal MRI over prenatal one. Altogether then postnatal results were partly discordant with prenatal ones in 9/25 cases (36 %). CONCLUSIONS: In most cases there was no added value of postnatal MRI as compared to prenatal one. This value lied in small details that could not have been noticed on prenatal MRI or required contrast medium administration to be noticed. On the other hand, MR examination performed with use of the dedicated neonatal coils in the MR-compatible incubator is a safe and reliable method of visualization of these small details with better spatial resolution thus helping to establish final diagnosis, treatment plan and prognosis.

Circle of Willis abnormalities in children with neurofibromatosis type 1.

BACKGROUND AND PURPOSE: The aim of the study was to assess anatomical variants and abnormalities in cerebral arteries on magnetic resonance angiography in 67 children with neurofibromatosis type 1 (NF1). MATERIALS AND METHODS: The study included 67 children aged 9 months to 18 years (mean 6.6 years). Control group comprised 90 children aged 2-18 years (mean: 11.8 years). All patients were examined at 1.5T scanner. RESULTS: We found cerebral arteriopathy (moyamoya disease) in one child (1.5%) in the study group. No aneurysms were found. Twenty-nine NF1 children (43.3%) had arterial anatomical variants. In 13 of them, more than one variant was diagnosed (44.8% of group with variants, 19.4% of study group). In control group, 19 children (21.1%) had variants, including four children with more than one variant (21% of group with variants, 4.4% of control group). Arterial variants were more common in NF1 patients compared with control group (p=0.026, binomial test for two proportions). Percentage of multiple variants was higher in study group than in control group, but this difference was not significant. Variants were more frequent on left side than on the right one (significant difference in control group; p=0.022, McNemara test). In study group, the number of left-sided anomalies (25) was similar to that of right-sided ones (22). There was no correlation between gender and variants, unidentified bright objects and variants or between optic gliomas and variants. CONCLUSIONS: Occurrence of arterial variants in NF1 patients was twofold higher than in control group. Multiple variants were more frequent in the study group although the difference did not reach statistical significance. Features of cerebral arteriopathy were found in one child with NF1.

The role of magnetic resonance imaging in the prenatal diagnosis of cleft lip and palate.

INTRODUCTION: Cleft lip and/or palate is the most common congenital craniofacial anomaly. Ultrasonography plays a key role in the early diagnosis of this anomaly and is completed by MRI. The purpose of this paper is to present and summarize the experience in diagnosis of cleft lip/palate by means of MRI. MATERIAL AND METHODS: The material consists of 62 fetuses that required more detailed evaluation which was conducted with the use of a 1.5 T scanner in SSFSE/T2 sequence in the sagittal, transverse and coronal plane. RESULTS: The cleft was diagnosed in 15 fetuses: an isolated cleft lip in one case (6.7%), a cleft lip and alveolar process in 2 (13.3%), a cleft lip and palate in 12 (80%). In eight fetuses (53.3%) the defect was unilateral, in 6 (40%) on both sides, in one case (6.7%) - a bilateral cleft lip and unilateral cleft palate was diagnosed. In three cases (20%), the cleft lip and/or palate defect was isolated, in 12 (80%) - it coexisted with other fetal abnormalities. MRI was less useful than ultrasound in 1 case (6.7%), in 4 cases (26.7%) it did not add any significant new information, in the remaining 10 cases (66.6%) important additional information was obtained on MRI. MRI revealed more details of the cleft in 5 cases (33.3%). In 10 fetuses (66.7%), cleft diagnosis was based on ultrasound and MRI only confirmed it. In 47 cases MRI allowed to show normal fetal faces, while there were difficulties of visualisation on ultrasound. CONCLUSIONS: Prenatal MRI is a method supporting fetal ultrasound and is used to confirm/expand sonographic diagnosis, but can also change it. In the case of cleft lip and palate fetal MRI produces a better picture of the connections between the cavities, the degree of involvement of the secondary palate and cleft extent, and also helps to detect/assess other associated fetal abnormalities.

First Experience with Neonatal Examinations with the Use of MR-Compatible Incubator.

BACKGROUND: Since 2003, very few publications have described brain examinations using neonatal MR-compatible incubator (INC). The authors present their first experience in these examinations, not limited to brain scans, with the use of an incubator equipped not only with head coil, but also with a coil designed for examinations of the spinal canal and spinal cord as well as the whole body, at the Institute of Mother and Child in Warsaw. MATERIAL/METHODS: Examinations were performed in 27 newborns (12 girls, 15 boys). Most of the neonates were prematurely born: 19 (70.4%) were born at gestational age of 23-37 weeks, mean of 30 weeks. They were examined at the corrected age of 26 weeks-1 month, mean of 36 weeks. Body weight of the newborns on the day of the study was 600-4,300 g, mean of 2,654 g. The study was performed with a GE Signa HDxT 1.5 T system with the use of a Nomag IC 1.5 incubator by Lammers Medical Technology Co., equipped with three coils: an eight-channel, phased-array head coil and a twelve-channel phased-array coil for the whole body, consisting of an eight-channel coil integrated in the incubator and a separate four-channel surface coil. RESULTS: Of the 27 children, 25 (92.6%) required a brain scan. Two children (7.4%) were referred to MRI for assessment of the spinal canal and the abdomen. We compared the results of transfontanelle ultrasound and MRI scans in 21 children. MRI provided significantly more diagnostic information in 18 cases (85.7%); in 3 cases (14.3%), no additional knowledge about the pathology was provided by the exam. CONCLUSIONS: The MR-compatible incubator increases the availability of MRI to newborns, especially premature newborns and those with low and extremely low body weight, for whom MR examinations are necessary to determine the extent of changes, not limited to the central nervous system, as well as to establish prognosis. Dedicated neonatal coils integrated with the incubator permit more accurate diagnosis than the previously used adult coils.

Diagnostic problems in case of twin pregnancies: US vs. MRI study.

AIM: To present an experience with twin pregnancies underlining the impact of magnetic resonance imaging (MRI) on diagnosis and management. METHODS: There were 17 cases of twin pregnancies: nine monochorionic [including four monochorionic diamniotic and five monochorionic monoamniotic (conjoined twins)] and eight dichorionic. The MRI examinations were performed between 19 and 39 weeks of gestational age in two centers using 1.5 T scanners (GE Signa Excite and GE Signa HDxt; GE Healthcare, Waukesha, WI, USA), always after ultrasound (US). In the first period of our activity, SSFSE sequence in T2-weighted images (SSFSE/T2WI) was the main diagnostic tool supported by TSE or GRE T1-weighted images (T1WI). After upgrading the scanners, diffusion-weighted imaging (DWI), steady-state free precession (FIESTA), and echoplanar GRE imaging (EPIGRE) became available. RESULTS: In 11 cases (64.7%), MRI was superior to US and supplied additional information, including two cases in which pathology of the second twin suspected on US was ruled out on the basis of MRI. In six cases (35.3%) MRI confirmed US diagnosis and brought no new data. CONCLUSION: MRI offers more detailed assessment of fetal pathology in cases of twin pregnancies, including conjoined twins, in which sonographic evaluation is more difficult than in single cases.

[Prenatal MRI as a method of controlling fetal pathology]. / Prenatalne badanie MR jako metoda kontroli patologii plodu.

BACKGROUND: It has been shown that MRI offers the possibility of more detailed assessment of fetal pathology than sonography. It is used not only to diagnose but also to follow up some prenatal diseases. It is a basis of in utero treatment and the tool of monitoring its efficacy The purpose of the study was to present the authors' experience with prenatal MRI as a method of follow-up of fetal pathology and of monitoring invasive fetal therapy MATERIAL AND METHODS: The study group consisted of 31 fetuses that underwent two MRI examinations. The first exams were performed at the gestational age of 19-28 weeks (mean: 23.6 weeks), the follow-up between week 20 and 37 (mean: 30.5). The MRI examinations were performed using 1.5 T scanners. SSFSE/T2-weighted images, TSE/ or GRE/T1-weighted images, DWI, FIESTA, EPIGRE were performed. RESULTS: In 5 cases MRI allowed to exclude a suspected pathology: brain anomaly in a healthy fetus, septo-optic dysplasia in a healthy fetus, right-sided CDH in case of a left-sided pathology pentalogy of Cantrell, lack of bladder in a fetus with a small, thick-walled bladder In 4 cases an additional pathology was detected on MRI: CCAM/ pulmonary sequestration with self-regression, cerebellar hypoplasia, rhombencephalosynapsis, tethered cord with syringohydromyelia. In 4 cases MRI was used just to follow-up and showed evolution of the disease in 2 cases: regression of intracerebral hemorrhage, progression of kidney disease. Finally, in 18 cases MRI was performed before and after an open fetal surgery of myelomeningocele showing good outcome in 10 cases and a wide spectrum of complications in 8 neonates: from edema of the transplant only in 4 to recurrent MC in 1. CONCLUSIONS: Maternal uterus constitutes a natural "incubator" for the fetus--it is easier and safer to perform diagnostic procedure in utero than in a seriously ill newborn. MRI is a method of choice in the diagnosis and of follow-up in cases of open fetal surgery.

Congenital Tumors-Magnetic Resonance Imaging Findings with Focus on Rare Tumors.

Congenital tumors are rare and, owing to this rarity, there is limited information on many of them. A total of 839 fetal and postnatal MRI studies performed in the first 3 months of life were retrospectively reviewed. They were performed with the use of 1.5 T scanners. Seventy-six tumors were diagnosed based on fetal MRI between 20 and 37 gestational weeks, and 27 were found after birth, from 1 day of age to 3 months of life. Teratomas were the most common tumors in our dataset, mainly in the sacrococcygeal region (SCT), followed by cardiac rhabdomyomas and subependymal giant cell astrocytomas (SEGA) associated with TSC, and neuroblastomas. The group of less common tumors consisted of infantile fibrosarcomas, malignant rhabdoid tumors, mesoblastic nephromas and Wilms tumor, craniopharyngiomas, brain stem gliomas, desmoplastic infantile astrocytoma, choroid plexus carcinoma, glioblastoma, hemangiopericytoma, rhabdomyosarcoma, melanoma, mesenchymal hamartomas of the chest wall and the liver, and juvenile xanthogranuloma, with special consideration of blue rubber bleb nevus syndrome. MRI plays a significant role in further and better characterization of congenital tumors, leading to a correct diagnosis in many cases, which is crucial for pregnancy and neonatal management and psychological preparation of the parents. No diagnosis is impossible and can be absolutely excluded.

Lesions in basal ganglia in a patient with involuntary movements as a first sign of diabetes - case report and review of the literature.

We present a case of unilateral hyperdensity of the lentiform and caudate nucleus on CT with hyperintesity on T1-weighted images on MRI in a 71-year-old woman with hemichorea-hemiballism and recently diagnosed diabetes.

Postradiotherapeutic changes and their evolution in MRI in children with aggressive soft tissue tumors.

BACKGROUND: Magnetic resonance imaging is a commonly used method of monitoring of soft tissue tumours. The aim of the work was to describe precisely the typical changes within soft tissues and bones occurring after radiotherapy in children treated for sarcomas and other soft tissue tumours. With time, the changes undergo evolution and their characteristics and comparison with previous examinations help in a difficult differentiation between tumour lesions and posttherapeutic changes. MATERIAL/METHODS: Fifteen children and young adolescents (9 boys and 6 girls) aged between 2 and 22 years (mean age of 13.4 years) with diagnosed aggressive soft tissue tumours, were treated with radiotherapy. There were 102 MRI examinations analysed in the period from February 2004 to February 2008. The examinations were performed with a 1.5T MRI scanner in the following sequences: SE T1, SE T1+fatsat, before and after gadolinium administration (Gd), FSE T2 and STIR in three planes, and, in some selected cases, a dynamic gadolinium-enhanced (DCE MRI) examination with FAME sequence. HISTOPATHOLOGICAL EXAMINATIONS SHOWED: rhabdomyosarcoma (RMS) in 8 cases, synovial sarcoma - 3, agressive desmoid fibroma - 3, mesenchymoma mal. - 1. MRI examinations were performed at different postradiotherapeutic stages, several times in one patient (12 times at the most). RESULTS: Every postirradiation stage revealed a typical picture of posttherapeutic changes. We distinguished four stages and described changes in different sequences within soft tissues and bones, as well as features of contrast enhancement and enhancement curves in a dynamic study. The stages included: I stage - early, up to 3 months after rth, II stage - chronic, from 3 months to 12 months after rth, with some differences between the following periods: • 3-9 months; 9-12 months; III stage - late, from 1 to 3 years after rth, IV stage - distant, more than 3 years after rth. In the early stage, there were 2 cases with a suspicious, equivocal image of postradiotherapeutic changes. In the chronic stage, there was one recurrence and one case of increasing changes after the therapy. However, the changes resolved in subsequent examinations. In the distant stage, we found two cases of a local recurrence. CONCLUSIONS: 1. MRI is a method of choice in the monitoring of treatment of aggressive soft tissue tumours and in diagnosis of recurrence. 2. To interpret the examination results, it is very important to know the MRI characteristics of changes after radiotherapy and their evolution with time. 3. Interpretation of MRI images and differentiation between postradiotherapeutic and neoplastic changes is difficult, especially at an early postradiotherapeutic stage. 4. A dynamic MRI examination may be useful in the differentiation between postradiotherapeutic and neoplastic changes but it may be unreliable at an early postradiotherapeutic stage. 5. When interpreting the results, it is very important to compare the image with the previous ones. It is therefore indicated to carry out a baseline MRI in the early postradiotherapeutic stage, and then further follow-up images, at several-month intervals.

Pneumococcal Meningitis and Its Sequelae - A Devastating CNS Disease.

INTRODUCTION: In countries where Haemophilus influenzae type B vaccine is used, Streptococcus pneumoniae is the most common cause of bacterial meningitis in young children and notable cause of morbidity/mortality. The authors present material of magnetic resonance imaging (MRI) of patients with pneumococcal meningitis from archive of Department of Diagnostic Imaging of Institute of Mother and Child in Warsaw. MATERIALS AND METHODS: We performed 27 brain MRI scans and 1 follow-up computed tomography (CT) in 10 children (2 girls and 8 boys) aged from neonate to 5 years at disease onset with proven pneumococcal infection. RESULTS: Follow-up period range was 0-12 years. Two children underwent only one MRI, one of them died before follow-up and the other was lost from further observation. There was one case of relatively benign disease course with mild changes on MRI. In another seemingly benign case, acute transient hydrocephalus was observed. Six children developed hydrocephalus, and two required ventriculoperitoneal shunting complicated by neuroinfection, shunt malfunction and revisions. Two patients developed epilepsy. In six children, spastic paresis of various severity was diagnosed, up to quadriplegia in one who is under the longest observation (>12 years) and survived in vegetative state. Three other children suffer from delayed psychomotor development to severe intellectual disability. CONCLUSIONS: MRI shows perfectly the degree of central nervous system (CNS) damage during and after pneumococcal invasion. Despite appropriate treatment, disease course may be unpredictably serious. Attempts to eliminate the obligation to vaccinate are extremely irresponsible taking into account potential danger of death, vegetative state or another form of severe damage to CNS. Social and financial costs of care of survivors are very high with shunts placements and changes, (neuro)infections, rehabilitation, families breakdown, etc.

Neonatal brain and body imaging in the MR-compatible incubator.

BACKGROUND: The use of a specialized MR-compatible incubator (INC) is very poorly described in the literature and only with regard to brain imaging. OBJECTIVES: To present our own experience with brain and body magnetic resonance imaging (MRI) in the INC in a large cohort of neonates. MATERIAL AND METHODS: A total of 555 examinations were performed in 530 newborns with the use of a 1.5T system and Nomag IC 1.5 incubator, equipped with head and body coils. RESULTS: More than half of neonates (54%) were prematurely born at 22 + 6-36 + 6 gestational weeks. They were examined from the first to 153 days of life (median: 18.5, mean: 37.7) with body weights 600-5000 g (mean: 3051 g), 23% of less than 2500 g. The proportion of brain MRIs to other body regions was 533:85 = 86%:14%. In 36.6% of cases, MRI showed more abnormalities than ultrasound (USG), in a further 21.8%, MRI diagnosis was completely different, in 4.7%, a pathology described on a USG was ruled out on MRI. The superiority of MRI over USG was 63.1%. CONCLUSIONS: MR-compatible incubator significantly increased the availability of MRI to newborns, especially to premature and unstable newborns. The integration of body coils into the INC increased the spectrum of examinations and made possible the scanning not only of the brain but also the body. Dedicated neonatal coils improved image quality and allowed more accurate diagnosis than the previously used adult coils. Immobilization of the babies in the INC by means of Velcro belts and head fixation inserts is better than in adult coils. The closed space of the INC isolates newborns to a greater extent from the negative influence of noise in the MR environment.

Magnetic resonance imaging as a diagnostic tool in case of ovarian masses in girls and young women.

BACKGROUND: Gynecological examination and transvaginal ultrasound are difficult or impossible in girls and young women who have not started their sexual life. CT is not a method of choice in this age group because of the ionizing radiation and iodine-containing contrast media. MRI is chosen then. MATERIAL/METHODS: Pelvic MRI was performed in 15 patients aged 9-19 years with suspected ovarian mass after they had had unclear gynecological and sonographic examinations. 1.5 T MRI systems were used. SE,T(F)SE and SPIR sequences were applied in T1- and T2-weighted images in three planes. Contrast media were administered in 7 patients. RESULTS: In a group of 3 girls with acute abdominal pain, polycystic ovaries, ovarian hemorrhagic cyst, and fibroma of the ovary were diagnosed. In a group of 11 patients with chronic abdominal pain, dermoid cysts of the ovaries were found in 7 cases, in one bilateral and accompanied by ectopic kidney. In 2 patients, serous cysts were diagnosed. In 2 cases an ovarian origin of the mass was excluded: multilocular cystic lesion in the presacral region and a hydatid mole were revealed. A neoplastic ovarian mass was diagnosed in a girl with increasing circumference of the abdomen. The accuracy of MRI in localizing lesions was 100%. Its accuracy in precisely characterizing lesions was 83.3%. CONCLUSIONS: Magnetic resonance imaging, with its noninvasiveness, high spatial resolution, and tissue specificity, is a method of choice in the diagnosis or exclusion of ovarian pathology in children and adolescents.

CNS Metastases from Bone and Soft Tissue Sarcomas in Children, Adolescents, and Young Adults: Are They Really So Rare?

Purpose. To check whether primary involvement of brain/spinal cord by bone/soft tissue sarcomas' metastases in children is as rare as described and to present various morphological forms of bone/soft tissue sarcomas' CNS metastases. Methods. Patients with first diagnosis in 1999-2014 treated at single center were included with whole course of disease evaluation. Brain/spinal canal magnetic resonance imaging (MRI)/computed tomography were performed in cases suspicious for CNS metastases. Extension from skull/vertebral column metastases was excluded. Results. 550 patients were included. MRI revealed CNS metastases in 19 patients (incidence 3.45%), 14 boys, aged 5-22 years. There were 12/250 osteosarcoma cases, 2/200 Ewing's sarcoma, 1/50 chondrosarcoma, 3/49 rhabdomyosarcoma (RMS), and 1/1 malignant mesenchymoma. There were 10 single metastases and 7 cases of multiple ones; in 2 RMS cases only leptomeningeal spread in brain and spinal cord was found. Calcified metastases were found in 3 patients and hemorrhagic in 4. In one RMS patient there were numerous solid, cystic, hemorrhagic lesions and leptomeningeal spread. Conclusions. CNS metastases are rare and late in children with bone/soft tissue sarcomas, although in our material more frequent (3.45%) than in other reports (0.7%). Hematogenous spread to brain and hemorrhagic and calcified lesions dominated in osteosarcoma. Ewing sarcoma tended to metastasize to skull bones. Soft tissue sarcomas presented various morphological forms.

Clinical effects of image interpretation.

There are different objective and subjective factors having an influence on interpretation of result of human body examination by means of diagnostic imaging methods. In report the examples of the most important and common diagnostic errors in patients suspect - or having tumor lesions in musculo-skeletal system are presented. Demonstrated cases were divided into two groups:
- patients with posttraumatic injuries, inflammatory changes, benign tumors or developing abnormalities in those delayed proper diagnosis did not have negative influence on final result of treatment,
- patients with malignant tumors in those wrong interpretation of images had dramatic influence on the treatment and eventual fatal fate.
As a reason of misinterpretation the authors regard among different: bad quality of examinations, lacking knowledge, carelessness or perhaps presumptions.

Neurocutaneous melanosis in children with giant congenital melanocytic nevi.

Twenty-four children with giant congenital melanocytic nevi underwent brain MRI at 1.5 T scanner. Melanin deposits in the brain were found in seven children (29.2%) located in temporal lobes, thalamus, cerebellum, and pons. One patient showed leptomeningeal involvement. Six patients were asymptomatic, and one had epilepsy. As opposed to previous reports, localization of skin nevi on anterior part of trunk was correlated to central nervous system involvement. In all patients with brain involvement skin nevi showed picture of compound nevus with neurofibromatic component.

MR images of bone lesions in children treated due to leukemia.

Leukemia is the most frequent malignancy in children (30-40%); acute lymphoblastic leukemia (ALL) accounts for 85% of cases of this leukemia. Apart from bone marrow infiltration, MR imaging reveals other lesions in the bones of these children, that may be a complication of the disease or of its therapy and do not require referral to the oncologist unless they are misinterpreted. These lesions include osteonecrosis, stress fractures due to osteopenia, osteomyelitis - often resulting from administration of corticosteroids. The authors present MR images of these lesions, often misinterpreted as leukemic infiltration.

Magnetic resonance imaging in the evaluation of the fetal spinal canal contents.

Ultrasonography (US) remains the first method in the evaluation of fetal central nervous system (CNS) abnormalities but in case of the spinal canal and cord it is often insufficient since the bony structures may obscure these structures. Prenatal magnetic resonance imaging (MRI) is therefore the final noninvasive tool for the assessment of these malformations allowing for correction of sonographic findings, revealing the full extent of complex lesions and choosing the candidates for in utero treatment. The authors present the most frequent anomalies of spinal canal and spinal cord in the consecutive phases of pregnancy, illustrated with their own MR images, with reference to the literature and own experience. In 58 out of 252 fetuses examined due to suspicion of CNS anomalies (23.0%) the spinal canal and spinal cord abnormalities were found on MRI. The cases of diastematomyelia, myelomeningocele, tethered cord, caudal regression syndrome, anterior meningocele, cystic sacrococcygeal teratoma and syringohydromyelia are demonstrated.

Brain development of the human fetus in magnetic resonance imaging.

INTRODUCTION: Ultrasonography is the first step in the in vivo evaluation of fetal central nervous system. However, it is not always easy--or even possible--to carry out this examination because of maternal obesity, oligo- or ahydramnios or fetal position. Magnetic resonance imaging becomes then the only method of assessment. Recognition of cerebral and cerebellar abnormalities requires detailed knowledge of normal development and morphology of the fetal brain. AIM: To show the sequence of fetal brain maturation on MR images on the basis of own material and equipment. MATERIAL AND METHOD: Seventy five fetuses without cerebral abnormalities were selected for the analysis of T2-weighted images of the brain obtained with use of GE Signa 1.5T scanners. No maternal sedation was used. Single-Shot Fast Spin Echo sequence (SSFSE) was applied in T2-weighted images in axial, sagittal and coronal planes in all fetuses. Fast Spoiled Gradient Echo (FSPGR) T1-weighted images were also obtained. RESULTS: The sequence of fetal brain maturation during the second half of pregnancy was elaborated and discussed. CONCLUSIONS: Magnetic resonance imaging is the most useful method of the evaluation of normal fetal brain development. It should be used as an additional tool in every case of diagnostic difficulties or uncertainty.