Multiparametric MRI prior to radical prostatectomy identifies intraductal and cribriform growth patterns in prostate cancer.

OBJECTIVES: To evaluate the diagnostic value of multiparametric prostate magnetic resonance imaging (mpMRI) prior to radical prostatectomy with curative intent for the detection of cribriform architecture (CA) and intraductal prostate cancer (IDC), which have recently been demonstrated to be adverse pathological features. PATIENTS AND METHODS: The study included 124 men who underwent mpMRI prior to radical prostatectomy at our centre. Preoperative mpMRI, prostatectomy histology and clinical follow-up details were reviewed retrospectively. The diagnostic value of mpMRI was evaluated on the basis of the detection rate. Secondly, the prognostic significance of CA/IDC among grade group (GG)2 cancers with regard to biochemical recurrence (BCR)-free survival was assessed using Kaplan-Meier analysis, with the log rank test and Fisher's exact test. RESULTS: Pathological examination of radical prostatectomy specimens identified CA/IDC in 89 of 124 cases (71%) and mpMRI identified 86/95 of tumours including any CA/IDC with a sensitivity of 90.5% (95% confidence interval 82.8-95.6%). When localization of the lesions was compared, there was an association between the highest Prostate Imaging-Reporting and Data System classification and the highest pathological grade in 106 of the 124 cases (85.5%). In patients with GG2 lesions, BCR occurred in 11 of 31 (35.5%) with CA/IDC and two of 21 (9.5%) without CA/IDC (P = 0.034). CONCLUSION: Multiparametric MRI has good sensitivity for detection of pathological primary prostate cancer, including most cases with CA/IDC; however, reliable prediction of GG2 tumours with CA/IDC for individual risk stratification remains challenging.

Lesion size on prostate magnetic resonance imaging predicts adverse radical prostatectomy pathology.

OBJECTIVES: To investigate the value of the maximal lesion diameter on preoperative multiparametric/bi-parametric magnetic resonance imaging for estimating the risk of adverse radical prostatectomy pathology. PATIENTS AND METHODS: Consecutive patients (n = 162) with prostate multiparametric or biparametric magnetic resonance images acquired before prostatectomy were retrospectively stratified into two groups: 65 patients with normal MRI (n = 18) or a suspicious lesion <15 mm in diameter (n = 47), and 97 patients with a lesion diameter ≥15 mm. The presence of extraprostatic extension, margin positivity, seminal vesicle invasion, and lymph node metastasis was examined in these groups using logistic regression analysis, including preoperative clinical parameters (prostate-specific antigen concentration, biopsy Gleason grade group, clinical T-stage, and D'Amico risk group). RESULTS: The prevalence of extraprostatic extension, margin positivity, and seminal vesicle invasion was 53.1% (86/162), 22.8% (37/162), and 17.9% (29/162), respectively. Lymphadenectomy was performed in 64 men, of whom 14 had lymph node metastasis. Lesion diameter ≥15 mm strongly predicted extraprostatic extension (Odds ratio: 7.94, 95% confidence interval: 3.87-16.28, p < 0.001), margin positivity (Odds ratio: 7.86, 95% confidence interval 2.63-23.51, p < 0.001), and seminal vesicle invasion (Odds ratio: 7.57, 95% confidence interval 2.18-26.22, p = 0.001). Lesion diameter ≥15 mm was an independent risk factor for adverse prostatectomy pathology. Lesion diameter ≥20 mm, but not ≥15 mm, was a significant risk factor for lymph node metastasis. CONCLUSION: Magnetic resonance imaging lesion diameter ≥15 mm is an independent risk factor for extraprostatic extension, margin positivity and seminal vesicle invasion.

Diagnostics of endometriosis by using magnetic resonance imaging.

Endometriosis affects about 2 to 10% of women in fertile age, It causes pain and infertility. In the ovaries, endometrios causes endometriomas. The disease may spread into the abdominal cavity and even result in ileus. Deep endometriomas are located under the peritoneal surface, typically behind the uterus and in the region of uterosacral ligaments. History, clinical examination and transvaginal ultrasound scanning usually lead to the diagnosis. Magnetic resonance imaging is in particular utilized prior to surgery. It provides a comprehensive view of endometriosis lesions in the pelvis, including deep foci.

Anatomical and functional changes to the pelvic floor after robotic versus laparoscopic ventral rectopexy: a randomised study.

INTRODUCTION AND HYPOTHESIS: To compare the effect of laparoscopic and robot-assisted ventral rectopexy for posterior compartment procidentia on the pelvic floor anatomy and function. METHODS: A prospective randomised single-centre study was carried out of 29 female patients, who underwent robot-assisted or laparoscopic ventral mesh rectopexy for external or internal rectal prolapse with symptoms of obstructive defecation and/or faecal incontinence. Anatomical changes were measured by Pelvic Organ Prolapse Quantification (POP-Q) and magnetic resonance defecography. Functional changes were evaluated using symptom questionnaires before and 3 months after surgery. RESULTS: After rectopexy, changes in POP-Q measurements were statistically significant for points Ap, Bp, C, D and Ba. The descent of the anorectum and cervix/vaginal cuff during straining were significantly reduced with regard to the reference line (mean, -10.4 ± 14.9 mm, p = 0.001) and (-13.3 ± 18.1 mm, p < 0.001) respectively. Pelvic organ mobility (POM) was reduced statistically significantly for the posterior (mean, -16.6 ± 20.8 mm, p < 0.001) and apical compartments (mean, -13.1 ± 14.8, p < 0.001). The PFDI-20, PFIQ-7 and PISQ-12 questionnaires showed statistically significant improvement of symptoms and sexual function. No significant differences were observed between the robot-assisted and laparoscopic techniques in terms of anatomical or functional parameters. CONCLUSION: Ventral mesh recto-colpo-sacropexy effectively corrects the anatomy of the posterior compartment, elevates the vaginal apex and reduces pelvic organ mobility of the posterior and middle compartments. The robot-assisted and laparoscopic techniques had similar anatomical and functional outcomes.

Prebiopsy Multiparametric Magnetic Resonance Imaging for Prostate Cancer Diagnosis in Biopsy-naive Men with Suspected Prostate Cancer Based on Elevated Prostate-specific Antigen Values: Results from a Randomized Prospective Blinded Controlled Trial.

BACKGROUND: Multiparametric magnetic resonance imaging (MP-MRI) may improve the detection of clinically significant prostate cancer (PCa). OBJECTIVE: To compare MP-MRI transrectal ultrasound (TRUS)-fusion targeted biopsy with routine TRUS-guided random biopsy for overall and clinically significant PCa detection among patients with suspected PCa based on prostate-specific antigen (PSA) values. DESIGN, SETTING, AND PARTICIPANTS: This institutional review board-approved, single-center, prospective, randomized controlled trial (April 2011 to December 2014) included 130 biopsy-naive patients referred for prostate biopsy based on PSA values (PSA <20 ng/ml or free-to-total PSA ratio ≤0.15 and PSA <10 ng/ml). Patients were randomized 1:1 to the MP-MRI or control group. Patients in the MP-MRI group underwent prebiopsy MP-MRI followed by 10- to 12-core TRUS-guided random biopsy and cognitive MRI/TRUS fusion targeted biopsy. The control group underwent TRUS-guided random biopsy alone. INTERVENTION: MP-MRI 3-T phased-array surface coil. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was the number of patients with biopsy-proven PCa in the MP-MRI and control groups. Secondary outcome measures included the number of positive prostate biopsies and the proportion of clinically significant PCa in the MP-MRI and control groups. Between-group analyses were performed. RESULTS AND LIMITATIONS: Overall, 53 and 60 patients were evaluable in the MP-MRI and control groups, respectively. The overall PCa detection rate and the clinically significant cancer detection rate were similar between the MP-MRI and control groups, respectively (64% [34 of 53] vs 57% [34 of 60]; 7.5% difference [95% confidence interval (CI), -10 to 25], p=0.5, and 55% [29 of 53] vs 45% [27 of 60]; 9.7% difference [95% CI, -8.5 to 27], p=0.8). The PCa detection rate was higher than assumed during the planning of this single-center trial. CONCLUSIONS: MP-MRI/TRUS-fusion targeted biopsy did not improve PCa detection rate compared with TRUS-guided biopsy alone in patients with suspected PCa based on PSA values. PATIENT SUMMARY: In this randomized clinical trial, additional prostate magnetic resonance imaging (MRI) before prostate biopsy appeared to offer similar diagnostic accuracy compared with routine transrectal ultrasound-guided random biopsy in the diagnosis of prostate cancer. Similar numbers of cancers were detected with and without MRI. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01357512.

Long-term hormonal follow-up after human Puumala hantavirus infection.

OBJECTIVE: Nephropathia epidemica (NE) is a haemorrhagic fever with renal syndrome (HFRS) caused by Puumala hantavirus (PUUV). Pituitary haemorrhage and hypopituitarism may complicate recovery from acute NE. DESIGN: Forty-seven of our recent cohort of 58 NE patients volunteered to be re-examined in order to estimate the burden of hormonal deficiency 4 to 8 years after the acute illness. Two patients had suffered from pituitary haemorrhage, but many others exhibited pituitary oedema during their acute infection. In this study, we searched for symptoms of hormonal deficiency, performed hormonal laboratory screening, and most patients underwent pituitary MRI examination. RESULTS: The pituitary size had diminished in all patients in whom MRI was performed (P < 0·001). One patient with acute phase haemorrhage had made a complete recovery while the other continued to require hormonal substitution. In addition, hormonal laboratory abnormalities were observed in nine other patients; these being attributable to several reasons, for example independent peripheral hormonal diseases, side effects of medication or other secondary causes such as obesity. None of them had signs of late-onset pituitary insufficiency caused by their previous NE. Health-related quality of life (mean and median 15D score) of patients was comparable to that of age-standardized general population. CONCLUSIONS: None of our patients had developed obvious late-onset hypopituitarism despite of the fact that pituitary gland can be affected during acute NE. We recommend requesting a history of hantavirus infection whenever the possibility of pituitary dysfunction is suspected at least in patients originating from regions with high NE infection rate.

[Incidental finding as a diagnostic and therapeutic challenge]. / Radiologinen sattumalöydös.

Incidental findings have increased with imaging studies. On the average, an incidental finding is made for one out of four patients in connection with an imaging study. The finding may be a harmless change without any significance for the patient's prognosis or treatment. Most incidental findings are indeed benign. On the other hand, an incidental finding may necessitate further investigations, follow-up or even immediate treatment in case of a malignant or other life-threatening change. Ideally, collaboration between a radiologist and a clinician leads to the correct decisions.

Survey of inappropriate use of magnetic resonance imaging.

OBJECTIVE: There are concerns that not all costly advanced imaging is appropriate. However, studies about the appropriateness of magnetic resonance imaging (MRI) are sparse. The aim of this study was to review various MRI examinations done at a university hospital to determine whether there is inappropriate use. METHODS: Altogether 150 common MRIs (upper abdomen or liver, lumbar spine, knee, head and head of children performed under anaesthesia, 30 each) were reviewed consecutively. The referrals and corresponding patient files were analysed by senior radiologists and the indications of the examinations were compared to the referral criteria. RESULTS: Seven per cent of the examinations were deemed inappropriate. All the MRIs of the head done on children were indicated. One to three examinations in all other subgroups were not indicated. The most common appropriate indications were ambiguous hepatic, pancreatic or adrenal lesions, prolonged lower back pain, suspicion of meniscus rupture, brain malignancy and developmental disorder of a child, respectively. CONCLUSIONS: Although the proportion of inappropriate examinations was not high; financial issues and the growing number of patients referred for MRI are of concern. Education and regular use of up-to-date referral guidelines could help to further improve appropriateness. MAIN MESSAGES: •Seven per cent of the MRI examinations analysed were inappropriate at a university hospital. •Everyday practices of a hospital may contribute to the level of appropriateness. •A survey of indications for previous MRI examinations might be helpful in various institutions.

Attempt to treat congenital pseudarthrosis of the tibia with mesenchymal stromal cell transplantation.

BACKGROUND AIMS: Congenital pseudarthrosis of the tibia (CPT) caused by neurofibromatosis type 1 (NF1) is a refractory disease occurring in childhood. We present two cases that had failed all earlier treatment attempts and, as a last treatment attempt, the patients were chosen to receive mesenchymal stromal cell (MSC) transplantation prior to amputation. METHODS: The MSC from bone marrow (BM) were harvested from the iliac crest and cultured in osteoinductive medium for 3 weeks. The cultured MSC were injected in solution into BM canals of the tibia and around the resection line or bone defect in a 3-dimensional collagen sponge scaffold. After the MSC transplantation, the patients were monitored during a 10-month follow-up period. In both cases, bone formation at the pseudarthrosis site was observed and two of three treated bone defects healed. For clinical reasons not related to cell transplantation, such as new infection and pseudarthrosis and severe shortening of the leg, both extremities were finally amputated and bone samples were analyzed to evaluate MSC therapy effect and safety. RESULTS: MSC transplantation normalized bone remodeling, promoted bone resorption and improved the overall structure of bone. The number of osteoclasts in the cortical bone was 2-fold higher compared with the monitored situation before MSC transfer. In addition, the mineral content of the bone improved after transplantation. We could see no sign of aberrant bone formation or malignant transformation. CONCLUSIONS: Our data suggest that MSC transplantation is a possibility for treatment of CPT caused by NF1 in less severe cases without adjunct defects.

Apparent diffusion coefficient on magnetic resonance imaging in pons and in corona radiata and relation with the neurophysiologic measurement and the outcome in very preterm infants.

BACKGROUND: New imaging techniques allow a detailed visualization of the brain and the findings possibly correlate with neurophysiologic measurements and neurosensory and motor outcomes. Postnatal clinical factors known to associate with neurologic disabilities may contribute to brain abnormalities not visible to the naked eye. OBJECTIVES: We evaluated whether quantitative measurement of organized water diffusion on MR imaging, apparent diffusion coefficient (ADC), relates to neurophysiologic function and to clinical risk factors and motor outcome in preterm infants. METHODS: Diffusion-weighted imaging was successfully performed at term age on 30 infants born <32 weeks of gestation, birth weight <1,000 g. Infants with major destructive brain lesions were excluded from the final analysis (n = 2). ADC was calculated within regions of interest placed in pons and in white matter regions known to contain motor fibers. Brain stem auditory evoked potentials (BAEP) were registered at term age. Gross motor outcome was assessed using Griffiths Scales at 2 years of corrected age. RESULTS: A positive correlation was found between ADC in the pons and the latency of wave III in BAEP (r = 0.619, p = 0.024). Need for inotrope support during the postnatal period and bronchopulmonary dysplasia associated with high ADC values in the pons and in the corona radiata. Infants with poor gross motor outcome had higher ADC in the corona radiata than infants with better outcome (mean = 1.343 vs. 1.197, p = 0.004). CONCLUSIONS: This is the first study to report a relationship between ADC and BAEP measurements in the pons. The study may add to the current knowledge about the relation between postnatal clinical factors and diffusion-weighted imaging when evaluating the high-risk infants.

Radiation-induced meningiomas: a shadow in the success story of childhood leukemia.

While the prognosis of acute childhood leukemia has improved, long-term survivors are increasingly experiencing late effects of the treatment. Cranially irradiated survivors are predisposed to the development of CNS tumors. Our aim was to describe the incidence of secondary brain tumors and to define the significance of treatment-related risk factors and host characteristics in a cohort of childhood leukemia survivors. Our cohort consisted of 60 consecutive cranially irradiated adult survivors of childhood leukemia treated in Oulu University Hospital (Oulu, Finland); MRI of the brain was performed on 49. The sites of the tumors, their histology, and details of the leukemia treatment were determined. Of the 49 patients, 11 (22%) 1-8 years of age at the time of diagnosis developed meningioma later in life, while no other brain tumors were seen. In this cohort, the development of meningioma seemed to show undisputable linkage with long latency periods (mean, 25 years; range, 14-34 years) and an increasing incidence 20 years after the treatment (47%). Three patients had multiple meningiomas, two had recurrent disease, and one had an atypical meningioma. Age at the time of irradiation, gender, or cumulative doses of chemotherapeutic agents showed no significant association with the development of meningiomas. The high incidence of meningiomas in this study was associated with long follow-up periods. Although the cohort is small, it seems probable that the increasing incidence of meningioma will shadow the future of cranially irradiated leukemia survivors. Systematic brain imaging after the treatment is therefore justifiable.

Unjustified CT examinations in young patients.

The doses of radiation from computed tomography (CT) are relatively high, yet CT is being increasingly utilized. Furthermore, the radiation-induced lifetime risk of cancer mortality is higher at younger age. The purpose of this study was to find out whether previous CT examinations done on patients aged under 35 years were justified, and if not, whether there would have been other, more justifiable imaging modalities available. Fifty CT examinations of the head and 30 CT examinations each of the lumbar spine, cervical spine, abdomen, nasal sinuses and trauma were evaluated consecutively since the beginning of the year 2005 by using electronic patient files, the referral guidelines for imaging recommended by the European Commission and certain principles of classification. Seventy-seven per cent of the CT examinations of the lumbar spine, 36% of the head, 37% of the abdomen, 20% of the nasal sinuses and 3% of the cervical spine were unjustified. Most of these unjustified examinations could have been replaced by magnetic resonance imaging. In order to reduce utilization of ionizing radiation, both the referring practitioner and the radiologist responsible for the examination should carefully consider the justification for CT examinations and the possibility of using other imaging modalities.

Osteonecrosis in children treated for lymphoma or solid tumors.

PURPOSE: The purpose of this study was to find out the incidence of and clinical risk factors for magnetic resonance imaging (MRI)-detected osteonecrosis (ON) in children treated for lymphoma or solid tumors. PATIENTS AND METHODS: The development of ON was studied in 32 childhood cancer patients who underwent MRI scanning of the lower extremities at the end of their treatment. The underlying malignancy was Wilms tumor in 8 patients, non-Hodgkin lymphoma (NHL) in 8, Hodgkin disease (HD) in 7, rhabdomyosarcoma in 6, and other occasional solid tumors in 3 patients. RESULTS: Six of the 32 patients (19%) had ON. The mean age of the patients with ON at diagnosis was 12.7 years compared with 5.8 years for the patients without ON (P<0.001). All the patients with ON had either HD (4 patients) or NHL (2 patients). Two (33%) of the patients with ON were symptomatic. CONCLUSIONS: ON in MRI was found to be a common complication in children after treatment for HD or NHL. The risk for ON seems to be very low in patients with other solid tumors even when they receive high cumulative doses of dexamethasone.

Ventricular tachyarrhythmia as a primary presentation of sarcoidosis.

AIMS: Sarcoidosis is a multisystem, granulomatous disease with occasional cardiac manifestations. The clinical course of patients with ventricular tachyarrhythmias as a primary presentation of sarcoidosis is mostly unknown. METHODS AND RESULTS: We describe nine patients (four males and five females) in whom sarcoidosis manifested as ventricular tachycardia (VT). The age of the patients was 53 +/- 10 years (range 33-68). The disease was diagnosed by endomyocardial biopsy in eight patients and by lymph node biopsy in one patient. The presenting arrhythmia varied from non-sustained VT to incessant VT and ventricular fibrillation. All patients received implantable cardioverter defibrillator (ICD) and anti-arrhythmic medication. High-dose steroid treatment was used in eight cases. During the follow-up (50 +/- 34 months), five patients underwent appropriate ICD therapies and non-sustained VT episodes were detected in four patients. Two patients developed incessant VT, which was treated by catheter ablation. One patient was referred for heart transplantation. CONCLUSION: Our data indicate that sarcoidosis can manifest as VT without any detectable systemic findings. This makes sarcoidosis an important diagnostic consideration in patients with VT of unknown origin. Arrhythmia control in cardiac sarcoidosis is difficult, and all modern treatments including high-dose steroids, anti-arrhythmic drugs, ICD, and catheter ablation are needed to suppress the arrhythmias.

High body mass index increases the risk for osteonecrosis in children with acute lymphoblastic leukemia.

PURPOSE: The aim of the study was to determine the incidence of and clinical risk factors for radiographic osteonecrosis (ON) in children treated for acute lymphoblastic leukemia (ALL) using the Nordic ALL protocols. PATIENTS AND METHODS: Ninety-seven consecutive patients with childhood ALL were studied prospectively by magnetic resonance imaging (MRI) of the lower extremities at the end of the treatment. RESULTS: Twenty-three (24%) of the 97 patients had ON. Seven of the patients (30%) were symptomatic, and three patients (13%) required surgical interventions. Multiple logistic regression analysis showed that high body mass index (BMI; P = .04), female sex (P = .01), older age at diagnosis (P < .001), and higher cumulative dexamethasone dose (P = .03) were independent risk factors for radiographic ON. The cumulative prednisone dose did not differ significantly between the patients with and without ON. The incidence of radiographic ON decreased significantly, from 36% to 7%, when the duration of dexamethasone exposure during the delayed-intensification phase was shortened from 3 to 4 weeks to 2 weeks with a taper (P = .001). CONCLUSION: ON as determined by MRI was found to be a common complication in children and adolescents after treatment with the Nordic ALL protocols. Revision of the ALL protocols by shortening the single exposure to dexamethasone has diminished the risk for ON remarkably. High BMI was identified as a new significant risk factor for ON.

MR-guided breast biopsy and hook wire marking using a low-field (0.23 T) scanner with optical instrument tracking.

The purpose of this study was to evaluate the technical feasibility of MR-guided percutaneous breast biopsy (LCNB) and breast hook wire marking in a low-field (0.23 T) MRI system with optical instrument tracking. MR-guided core biopsy and/or hook wire marking was performed on 13 lesions observable at MR imaging only. Seven breast LCNBs and 10 hook wire markings were performed under MR guidance on 11 patients. The diagnosis was confirmed by excision biopsy or mastectomy in 12 lesions and with histopathological and cytological diagnosis and 12-month clinical follow-up in one lesion. All lesions seen in the high-field scanner were also successfully identified and targeted in the low-field scanner. The following procedures were typically technically successful. There were difficulties due to unsatisfactory functioning of some core biopsy guns. Detailed description of low-field MR guidance and optical tracking in breast biopsies is provided. The procedure seems accurate and safe and provides means to obtain a histological diagnosis of a breast lesion only seen with MRI. The low-field biopsy system is comparable to the high-field MRI system. MR-compatible biopsy guns need to be improved.

Population cohort associating chorioamnionitis, cord inflammatory cytokines and neurologic outcome in very preterm, extremely low birth weight infants.

Intrauterine inflammation may relate to neurologic disability among preterm children. We investigated the relationship between chorioamnionitis, cord serum cytokines, and neurologic outcome. Sixty-one consecutively born very preterm extremely low birth weight (ELBW) infants were prospectively enrolled. Histologic inflammation in placenta and umbilical cord and vascular pathology were evaluated. Cord sera were analyzed for five proinflammatory cytokines. Serial brain ultrasound and magnetic resonance imaging were performed for evaluation of intraventricular hemorrhage (IVH grade I-III) and white matter damage (WMD: cystic periventricular leukomalacia or IVH grade IV). Neurologic and neurocognitive outcomes were assessed at the corrected age of 2 y. The incidences of HCA, WMD, and abnormal neurologic outcome were 48%, 13% and 19%, respectively. HCA or high IL-6 in cord serum predicted spontaneous preterm labor with high accuracy. HCA increased the risk of IVH grade II-III. In HCA, without either clinical chorioamnionitis or histologic placental perfusion defect, the children had a low risk of WMD (0%) and a low risk of abnormal neurologic outcome (6%). In HCA, the concentration of IL-6 in cord serum was lower in children with abnormal neurologic outcome than in children with normal neurologic outcome. In HCA and placental perfusion defect (compound defect) the risk of abnormal neurologic outcome was high. Compound placental defect and WMD additively predicted abnormal neurologic outcome. We propose that HCA together with other insults (placental perfusion defect or maternal systemic infection) increases the risk of poor neurologic outcome in very preterm ELBW infants.

Low-field versus high-field MRI in diagnosing breast disorders.

We evaluated the performance of low-field MRI in breast disorders by comparing it with high-field MRI and biopsy results. Twenty-eight consecutive patients who were able to undergo two magnetic resonance examinations on following days were examined by high-field and low-field MRI. After T1-weighted sagittal images had been obtained a dynamic 3D axial study was performed followed by the acquisition of contrast-enhanced T1-weighted sagittal images. The images were analyzed separately by two radiologists paying attention to lesion morphology and enhancement kinetics. Six patients had problems in both breasts (34 breasts studied). The results were compared with biopsy results of 27 breasts. There were 16 malignant lesions, two fibroadenomas and nine other benign lesions. The inter-magnetic-resonance-scanner kappa value was 0.77 (substantial agreement), while the interobserver kappa value was 0.86 and 0.81 at low and high field, respectively (excellent agreement). The sensitivity was 100 and 100%, the specificity was 82 and 73% and the accuracy was 93 and 89% at low and high field, respectively. The mean lesion size was 2 cm and the smallest malignant lesion was 8 mm in diameter. Low-field MRI is a promising tool for breast imaging. Larger materials and smaller lesions are needed to evaluate its true sensitivity and specificity.

Perfusion MRI and SPECT of brain after treatment for childhood acute lymphoblastic leukemia.

BACKGROUND: Treatment of childhood leukemia may cause perfusion defects in the brain observed by SPECT. Perfusion MRI is a novel method to study brain perfusion which has not been used previously in this setting. This study was performed to compare SPECT with perfusion MRI in patients with acute lymphoblastic leukemia (ALL) after treatment. PROCEDURE: Nineteen children or young adults underwent perfusion MRI at the cessation of treatment (n = 9) or 4-8 years after the treatment (n = 10). Seventeen of them also underwent SPECT at the time of MRI (within 0-3 days, n = 14) or a couple of months later (1.5-6 months, n = 3). SPECT images and relative cerebral blood volume (CBV) and cerebral blood flow (CBF) maps from perfusion MRI were analyzed visually. Relative CBV ratios of gray matter to white matter and thalamus to white matter were also calculated from the perfusion MRI. RESULTS: Perfusion MRI did not show any focal perfusion defects, while small defects were observed by SPECT in five of 17 children (29%) in the basal, frontal or temporal areas on the left. No significant differences were observed by perfusion MRI in the relative CBV ratios in the different treatment groups. Time since treatment, age at diagnosis, brain irradiation, or findings in conventional MRI or SPECT did not have any effect on the relative perfusion values either. CONCLUSIONS: SPECT may show small perfusion defects after treatment for childhood leukemia which are not visible by perfusion MRI. The clinical significance or prognosis of these defects is not known.