Israel Medical Association Journal

Background: Magnetic resonance imaging of the breast has emerged as a valuable imaging tool in addition to conventional imaging modalities. It has high sensitivity for malignant lesions, and can detect mammographically, sonographically and clinically occult cancers. “MR only” lesions are best biopsied under MR guidance; however, this may be a challenging task.

Objectives:  To evaluate our initial clinical experience with MR-guided core needle breast biopsy and MR-guided needle localization.

Methods: We retrospectively evaluated 81 women with 97 lesions, who were scheduled for guided core needle biopsy or MR-guided needle localization followed by surgery. Lesions were categorized as malignant, high risk, or benign according to the BI- RADS MR classification system. MR findings were compared with final histopathology or with follow-up imaging findings.

Results: Fifteen (16%) lesions were malignant (9 invasive ductal carcinoma, 2 invasive lobular carcinoma, 4 ductal carcinoma in situ); 7 (7%) lesions were high risk (4 atypical ductal hyperplasia, 3 radial scars); 75 (77%) lesions were benign, mainly fibrocystic changes. Other benign findings were sclerosing adenosis, pseudoangiomatous stromal hyperplasia, fat necrosis, intraductal papilloma, fibroadenoma, capillary hemangioma, and florid ductal hyperplasia. No major complications were encountered.
Conclusions: MR-guided interventional procedures of the breast are accurate, safe and feasible methods for sampling breast lesions detected only by MR and have become a significant tool in the management of certain patients.

Background: Stem cell-based therapy is a promising approach for the treatment of neurodegenerative disease. In our laboratory, a novel protocol has been developed to induce bone marrow-derived mesenchymal stem cells into neurotrophic factor-secreting cells. These cells produce and secrete factors such as BDNF (brain-derived neurotrophic factor) and GDNF (glial-derived neurotrophic factor).

Objectives: To evaluate the migratory capacity and efficacy of NTF-SC[1] in animal models of Parkinson's disease and Huntington's disease.

Methods: MSCs[2] underwent two-phase medium-based induction. An efficacy study was conducted on the 6-hydroxydopamine-induced lesion, a rat model for Parkinson's disease. Cells were transplanted on the day of 6-OHDA[3] administration, and amphetamine-induced rotations were measured as a primary behavioral index. In a second experiment, migratory behavior was examined by transplanting cells a distance from a quinolinic acid-induced striatal lesion, a rat model for Huntington's disease. Migration, in vivo, was monitored using longitudinal magnetic resonance imaging scans followed by histology.

Results: NTF-SCs attenuated amphetamine-induced rotations by 45%. HPLC analysis demonstrated a marked decrease in dopamine depletion, post-cellular treatment. Moreover, histological assessments revealed that the engrafted cells migrated and acted to regenerate the damaged striatal dopaminergic nerve terminal network. In a preliminary work on an animal model for Huntington's disease, we demonstrated by high resolution MR images and correlating histology that induced cells migrated along the internal capsule towards the QA[4]-induced lesion.

Conclusions: The induced MSCs are a potential therapy for neurodegenerative diseases, due both to their NTF secretion and their ability to migrate towards the diseased tissue.

Background: Manganism is a central nervous system disorder caused by toxic exposure to manganese. Manganism has been related to occupational exposures, liver diseases, prolonged parenteral nutrition, and abuse of illicit drugs. Initially manifested by a reversible neuropsychiatric syndrome (locura manganica), the main symptoms and signs of manganism are emotional lability, compulsive behavior and visual hallucinations. Locura manganica is followed by an irreversible extrapyramidal syndrome, the onset of which occurs years after chronic exposure.

Objectives: To characterize the regional distribution of Mn[1] in the rat brain after subchronic exposure to Mn. This animal model holds special clinical relevance, reflecting the earlier clinical stages of manganism before chronic exposure to Mn exerts its irreversible effects.

Methods: Sprague-Dawley rats were intravenously injected with MnCl₂ weekly, for a total of 14 weeks – approximately 1/10 of the lifetime of the rat. T1-weighted magnetic resonance imaging was used to detect the distribution of Mn deposition in brain tissues, as evidenced by areas of T1-weighted hyperintense signals.

Results: A consistent region-specific pattern of T1-weighted hyperintensities was observed in the brains of Mn-treated rats. Cortical hyperintensities were prominent in the hippocampus and dentate gyrus. Hyperintensities were also observed in the olfactory bulbs, pituitary gland, optic nerves and chiasma, pons, midbrain tegmentum, habenula, lentiform and caudate nuclei, thalamus, chorioid plexus and cerebellar hemispheres.

Conclusions: Prominent Mn depositions, evidenced by T1-weighted hyperintensities in the hippocampus after subacute exposure to Mn, are compatible with the clinical picture of manganism during its early stages; and may explain its pathophysiology.  

Background: Occult breast cancer without clinically or mammographically detectable breast tumor is an uncommon presentation.

Objectives: To assess the role of breast MRI in women with metastatic carcinoma and an occult primary, and to define the MRI characteristics of the primary breast tumor.

Methods: This retrospective study evaluated 20 women with metastatic carcinoma of unknown origin who underwent breast MRI between 2000 and 2006. Four women were excluded, leaving 16 in the study group. Probability of malignancy was assessed according to BIRADS classification. MRI performance in detecting lesions and evaluating disease extent was assessed, with the gold standard being surgical or biopsy pathology.

Results: MRI detected suspicious lesions in 15 patients. Lesion size ranged from 0.4 to 7 cm (median 1.5 cm). MRI detected a single lesion in 6 patients (40%), multifocal disease in 3 (20%), multicentric disease in 4 (27%), and bilateral breast lesions in 2 (13%). In 13 patients MRI depicted the primary breast cancer. Initial treatment was surgical in nine; MRI correctly estimated disease extent in 6 (67%), underestimated disease extent in 1 (11%), and overestimated it in 2 (22%). Four patients had biopsy followed by chemotherapy; one had multicentric disease and one had multifocal disease. MR findings were false positive in two patients and false negative in one.

Conclusions: MRI is sensitive in detecting the primary tumor and beneficial in assessing tumor extent. Small size and multiple foci are common features. We suggest that bilateral breast MRI be part of the evaluation of women with metastatic carcinoma and an occult primary.
 

Background: Magnetic resonance imaging is a diagnostic tool of growing importance. Since its introduction, certain medical implants, e.g., pacemakers, were considered an absolute contraindication, mainly due to the presence of ferromagnetic components and the potential for electromagnetic interference. Patients with such implants were therefore prevented from entering MRI systems and not studied by this modality. These devices are now smaller and have improved electromechanical interference protection. Recently in vitro and in vivo data showed that these devices may be scanned safely in the MRI.

Objectives: To report our initial experience with three patients with pacemakers who underwent cerebral MRI studies.

Methods: The study included patients with clear clinical indications for MRI examination and who had implanted devices shown to be safe by in vitro and in vivo animal testing. In each patient the pacemaker was programmed to pacing-off. During the scan, continuous electrocardiographic telemetry, breathing rate, pulse oximetry and symptoms were monitored. Specific absorption rate was limited to 4.0 W/kg for all sequences. Device parameters were assessed before, immediately after MRI, and 1 week later.

Results: None of the patients was pacemaker dependent. During the MRI study, no device movement was felt by the patients and no episodes of inappropriate inhibition or rapid activation of pacing were observed during the scan. At device interrogation here were no significant differences in device parameters pre-, post-, and 1 week after MRI. Image quality was unremarkable in all imaging sequences used and was not influenced by the presence of the pacemaker.

Conclusion: Given appropriate precautions, MRI can be safely performed in patients with a selected permanent pacemaker. This may have significant implications for current MRI contraindications.  

Objectives: To establish the impact of breast MRI on women undergoing testing in our institution.

Methods: We analyzed 82 cases that underwent MRI between January 2001 and April 2003. Analysis appraised the clinical impact of MRI testing in cases where medical summaries were available.

Results: Studies were categorized into five indications: a) screening in high risk women (n=7), b) search for primary disease in the presence of disease (n=5), c) monitoring of chemotherapy (n=2), d) postoperative assessment of tumor bed (n=9), and e) diagnostic/characterization of primary or recurrent breast cancer (n=59). Results were defined as negative, positive or no impact on clinical management. MRI testing had a positive impact in 62 cases, affecting measurable change in 9 cases. Benefit was seen in screening, diagnosis and postoperative cases. In 15 cases, MRI stimulated investigations.

Conclusion: MRI is a valuable tool in breast imaging and affects management. Further trials are necessary to define clearly the role of MRI and to ascertain whether in cases where beneficial impact on management is noted, there is ultimate impact on outcome. 

Gadolinium-based agents are widely used in magnetic resonance imaging as contrast agents. These agents are radio-opaque enough for diagnostic imaging of the vascular tree by using digitally subtracted images as well as for imaging of the biliary system and the urinary tract. The recommended doses for gadolinium do not impair renal function or cause adverse reactions in patients with iodine sensitivity; thus patients with such conditions can safely undergo diagnostic angiography, either by MRI angiography or by catheterization using gadolinium as contrast agent, for diagnostic and therapeutic purposes.