Brain magnetic resonance imaging after high-dose chemotherapy and radiotherapy for childhood brain tumors.

PURPOSE: Brain necrosis or other subacute iatrogenic reactions has been recognized as a potential complication of radiotherapy (RT), although the possible synergistic effects of high-dose chemotherapy and RT might have been underestimated. METHODS AND MATERIALS: We reviewed the clinical and radiologic data of 49 consecutive children with malignant brain tumors treated with high-dose thiotepa and autologous hematopoietic stem cell rescue, preceded or followed by RT. The patients were assessed for neurocognitive tests to identify any correlation with magnetic resonance imaging (MRI) anomalies. RESULTS: Of the 49 children, 18 (6 of 25 with high-grade gliomas and 12 of 24 with primitive neuroectodermal tumors) had abnormal brain MRI findings occurring a median of 8 months (range, 2-39 months) after RT and beginning to regress a median of 13 months (range, 2-26 months) after onset. The most common lesion pattern involved multiple pseudonodular, millimeter-size, T1-weighted unevenly enhancing, and T2-weighted hyperintense foci. Four patients with primitive neuroectodermal tumors also had subdural fluid leaks, with meningeal enhancement over the effusion. One-half of the patients had symptoms relating to the new radiographic findings. The MRI lesion-free survival rate was 74%+/-6% at 1 year and 57%+/-8% at 2 years. The number of marrow ablative courses correlated significantly to the incidence of radiographic anomalies. No significant difference was found in intelligent quotient scores between children with and without radiographic changes. CONCLUSION: Multiple enhancing cerebral lesions were frequently seen on MRI scans soon after high-dose chemotherapy and RT. Such findings pose a major diagnostic challenge in terms of their differential diagnosis vis-à-vis recurrent tumor. Their correlation with neurocognitive results deserves further investigation.

Multicenter comparative multimodality surveillance of women at genetic-familial high risk for breast cancer (HIBCRIT study): interim results.

PURPOSE: To prospectively compare clinical breast examination (CBE), mammography, ultrasonography (US), and contrast material-enhanced magnetic resonance (MR) imaging for screening women at genetic-familial high risk for breast cancer and report interim results, with pathologic findings as standard. MATERIALS AND METHODS: Institutional review board of each center approved the research; informed written consent was obtained. CBE, mammography, US, and MR imaging were performed for yearly screening of BRCA1 or BRCA2 mutation carriers, first-degree relatives of BRCA1 or BRCA2 mutation carriers, or women enrolled because of a strong family history of breast or ovarian cancer (three or more events in first- or second-degree relatives in either maternal or paternal line; these included breast cancer in women younger than 60 years, ovarian cancer at any age, and male breast cancer at any age). RESULTS: Two hundred seventy-eight women (mean age, 46 years +/- 12 [standard deviation]) were enrolled. Breast cancer was found in 11 of 278 women at first round and seven of 99 at second round (14 invasive, four intraductal; eight were

A method for dynamic subtraction MR imaging of the liver.

BACKGROUND: Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR) volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. METHODS: Nineteen consecutive patients (median age 45 years; range 37-67) were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20 degrees , slice thickness 1.5 mm) acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a) rigid 3D translation using maximization of normalized mutual information (NMI), and (b) fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. RESULTS: The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 +/- 0.031 vs. 0.078 +/- 0.031, n.s., paired t-test) and by a further 23% (0.096 +/- 0.035 vs. 0.078 +/- 0.031, p < 0.001, paired t-test) after non-rigid realignment. The overall average NMI increase was 31%. CONCLUSION: This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.

MRI in the early detection of breast cancer in women with high genetic risk.

AIMS AND BACKGROUND: Women with BRCA1 or BRCA2 germline mutations have an elevated risk of developing breast and/or ovarian cancer. Because of the early onset of the disease, screening of this group of women should start at an earlier age than in the general population. The association of breast magnetic resonance imaging (BMRI) and ultrasonography (US) with mammography (MX) and clinical breast examination (CBE) in the regular surveillance of these individuals has been proposed and seems to improve the early detection of breast cancer. METHODS: Within a multicenter study started by the Istituto Superiore di Sanità (Rome), at the Istituto Nazionale Tumori of Milan (INT) we enrolled 116 women at high genetic risk for breast cancer; they were either BRCA1 or BRCA2 mutation carriers or had a strong family history of breast cancer. They underwent CBE, MX, US and BMRI once a year. RESULTS: Between June 2000 and April 2005, at INT 12 cancers were detected among the 116 screened individuals (10%). In this subgroup, 1 patient refused BMRI and in 2 cases US was not performed. With BMRI we found 11 cancers and 6 of them were detectable only by this technique. In these 6 cases, the size of the disease was less than 1 cm and MX was false negative due to irregularly nodular parenchyma in 4 cases and scar tissue or prosthesis in the other 2. US was not performed in 2 cases and was false negative in 4 cases. Three false positive results were found with BMRI: 1 case was considered suspect but related to hormonal influences; 1 case with the same pattern was sent for second-look US, which gave a negative result and BMRI review after 6 months showed normalization of the parenchyma; in the third case histology revealed the presence of adenosis. No false positive results were registered for MX. CONCLUSIONS: The aim of secondary prevention is the detection of cancer at its earliest stage. BMRI screening in women with BRCA1 or BRCA2 mutations or at high familiar risk appears to be highly sensitive and may detect mammographically occult disease. The accuracy of MR imaging is higher than that of conventional imaging but the technique is flawed by a lower specificity. In order to avoid unnecessary biopsies we believe that the combination of BMRI and conventional imaging can be very useful in screening women with a high genetic risk of breast cancer, especially with second-look evaluation by means of US when BMRI yields the only positive diagnostic result. Second-look US has been demonstrated to be of critical importance both in recognizing false positive BMRI results and in guiding biopsies, when necessary.

Breast MRI screening in patients with increased familial and/or genetic risk for breast cancer: a preliminary experience.

AIMS AND BACKGROUND: Breast cancer is the most common cancer affecting women, and it is associated with or due to a genetic predisposition in 5%-10% of the cases. Owing to the higher risk of developing breast cancer and the early onset of the disease in women proved or suspected to be carriers of a breast cancer susceptibility gene, a dedicated screening should be offered as a less invasive approach with the otherwise suggested prophylactic mastectomy. This should be optimized in order to overcome the limitations of conventional breast imaging with the application of new technologies such as breast magnetic resonance imaging. METHODS: A diagnostic protocol for routine control in patients at high risk of developing breast cancer has been prepared. Within a 7-month period, 23 patients suspected or proved to carry a breast cancer susceptibility gene underwent breast magnetic resonance imaging. RESULTS: Four breast cancers were identified with breast magnetic resonance imaging. In these cases, mammography was negative because of the density of the parenchyma or for its fibroglandular pattern. Ultrasound was negative in 2 cases, not specific for malignancy in 1 case, and considered as only possibly malignant but with biopsy recommendation on the basis of magnetic resonance findings in the last one. Clinical analysis was positive for a mass in 2 cases. CONCLUSIONS: The accuracy of breast magnetic resonance imaging is known to be higher than that of conventional imaging in the study of breast parenchyma. High spatial resolution, no breast density influence and multiplanarity can give more detailed information about the smaller lesions and the right extension of the disease. Preliminary studies where breast magnetic resonance imaging is performed in addition to mammography within this group of patients are encouraging. We also believe that the application of breast magnetic resonance imaging can be very useful in the detection of cancer as early as possible with the aim to obtain the highest chance of survival after treatment.

Breast microcalcifications studied with 3D contrast-enhanced high-field magnetic resonance imaging: more accuracy in the diagnosis of breast cancer.

AIMS: To evaluate the reliability of magnetic resonance imaging (MRI) performed with three-dimensional (3D) sequences in mammographically detected breast microcalcifications. METHODS: During an 8-month period, a group of 28 patients with mammographically detected microcalcifications suspicious for malignancy underwent MRI. Their ages ranged from 33 to 65 years. Examinations were performed with a 1.5 Tesia MR unit and a 3D T1 weighted sequence. Images were interpreted on the basis of morphologic parameters and dynamic behavior in the uptake of contrast medium (Gd-DTPA). Histologic findings were considered as the gold reference. RESULTS: Histologic analysis revealed invasive carcinoma in 7 patients, 3 of which were associated with foci of lobular carcinoma in situ. Intraductal carcinoma was diagnosed in 8 patients, 1 of which was associated with a tubular carcinoma. Benign lesions accounted for 13 patients. All the neoplastic conditions showed enhancement on MR images (sensitivity, 100%), whereas early and intense enhancement was noted in 5 of 13 benign lesions (specificity, 61%). The positive predictive value was 75% and negative predictive value, 100%. CONCLUSIONS: Although an overlap in the enhancement behavior of malignant and some benign lesions is clearly evident, a careful interpretation of MR images is helpful in detecting and mainly ruling out breast cancer combined with mammographically suspicious microcalcifications.

Ressonância magnética do esôfago; aspecto normal / Magnetic resonance imaging of the esophagus; normal appearance

Utilizamos um aparelho de ressonância magnética a alto campo magnético (1,5T) para realizarmos o estudo dos parâmetros normais do esôfago torácico em 40 pacientes sem evidência clínica de doença esofagiana. Os parâmetros analisados foram os diâmetros ântero-posterior e transversal do órgäo, a incidência de ar no seu interior, a espessura de sua parede e o ângulo de contacto com a orta, a presença ou ausência de plano de clivagem periesofagiano e o aspecto da parede posterior da traquéia. A representaçäo anatômica foi também avaliada notando-se que os terços superior e médio do esôfago torácico säo bem visualizados em 92,5% dos casos. Entre os resultados encontrados, a ausência de plano de clivagem adiposo periesofagiano näo permite utilizar esse parâmetro como sinal de invasäo de estruturas vizinhas pela neoplasia do esôfago, sugerido por diversos autores através da tomografia computadorizada e mesmo da ressonância magnética