Secondary Imaging Modalities Research Articles

Diagnosis of central nervous system abnormalities: comparison of prenatal neurosonography and foetal magnetic resonance imaging findings

Magnetic resonance imagining (MRI) is gradually becoming the more preferred imaging modality in the evaluation of central nervous system (CNS) abnormalities rather than foetal ultrasonography (USG). The aim of this study was to compare the findings of prenatal neurosonography and foetal MRI. The study was a retrospective study analysing the records of 160 pregnant women who underwent both foetal MRI and USG due to suspicion of CNS abnormalities between 2008 and 2019. Indications for applying foetal MRI were neurosonography and foetal MRI findings. When the compatibility between MRI and USG results was examined in CNS abnormalities, it was found fully compatible in 61.3% of cases, partially compatible in 24.53% of cases, and not compatible in 14.5% of cases. When comparing prenatal neurosonography and foetal MRI findings, additional findings were reported in 16.9% of cases, and no additional finding was reported in 66.8% of cases. While normal anatomical findings were reported in 8.8% of the cases in MRI, the diagnosis made by neurosonography changed in 7.5%. Foetal MRI has more advantages than USG both in imaging the CNS abnormalities in more detail and in determining the accompanying additional anomalies. IMPACT STATEMENT What is already known on this subject: USG is a safe, practical and cost-effective primary imaging method that is widely used for foetal anomaly screening. However, there may sometimes be difficulties in evaluating the foetal brain structures due to foetal position which is unsuitable for imaging, extremely obese with a high body mass index, oligohydramnios and ossified foetal skull. For this reason, magnetic resonance imaging (MRI) is used as the most commonly used imaging method after USG in the evaluation of foetal anatomy, especially CNS. What do the results of this study add?: In our study, we saw that foetal MRI has more advantages than neurosonography in both seeing CNS abnormalities in more detail and recognising additional anomalies that may accompany. What are the implications of these findings for clinical practice and/or further research?: We have seen that besides neurosonography, foetal MRI can provide important information that can affect the clinical approach in pregnancy management by increasing the correct diagnosis in pregnancies with congenital CNS abnormalities. MRI: it is the best secondary imaging modality that can aid diagnosis in addition to neurosonography in the diagnosis of CNS abnormalities and in suspected cases. Therefore, foetal MRI should be used more widely in prenatal diagnosis.

Quantifying accuracy and heterogeneity in single-molecule super-resolution microscopy

The resolution and accuracy of single-molecule localization microscopes (SMLMs) are routinely benchmarked using simulated data, calibration rulers, or comparisons to secondary imaging modalities. However, these methods cannot quantify the nanoscale accuracy of an arbitrary SMLM dataset. Here, we show that by computing localization stability under a well-chosen perturbation with accurate knowledge of the imaging system, we can robustly measure the confidence of individual localizations without ground-truth knowledge of the sample. We demonstrate that our method, termed Wasserstein-induced flux (WIF), measures the accuracy of various reconstruction algorithms directly on experimental 2D and 3D data of microtubules and amyloid fibrils. We further show that WIF confidences can be used to evaluate the mismatch between computational models and imaging data, enhance the accuracy and resolution of reconstructed structures, and discover hidden molecular heterogeneities. As a computational methodology, WIF is broadly applicable to any SMLM dataset, imaging system, and localization algorithm.

Accuracy of Ultrasound-Guided versus Landmark-Guided Intra-articular Injection for Rat Knee Joints

Our aim was to test the effectiveness of ultrasound-guided intra-articular (IA) injection into the knee joint of rodents by an inexperienced operator compared with standard landmark-guided IA injections by a trained injector. Fifty landmark-guided and 46 ultrasound-guided IA injections in 49 rats were analyzed. Animal positioning and injection protocol were designed for use with the ultrasound system. Injection delivery was verified with a secondary imaging modality. We compared the success of IA injections by method (landmark and ultrasound-guided), adjusting for all other confounding factors (age, weight, experience, laterality and presence of surgery). Ultrasound-guided injections had higher success rates overall (89% vs. 58%) and helped to reduce the number of failed attempts per injection. None of the cofounding factors influenced the success of injection. In conclusion, we found higher accuracy for ultrasound-guided IA injection delivery than the traditional landmark-based injection method and also the technical feasibility for untrained personnel.

Persistent Extreme Hyperextension of the Fetal Neck: Clinical and Neuroimaging Findings.

Persistent hyperextension of the fetal craniocervical junction or neck is one of several fetal positions commonly observed on prenatal imaging. Underlying fetal structural etiologies such as fetal neck masses and iniencephaly can be detected as causes of hyperextension. Caesarean delivery is considered in cases of vaginal delivery or obstructed labor for fear of cervical spinal cord injury. In this case series, we describe the prenatal magnetic resonance imaging (MRI) findings and their potential role in obstetric management and discuss postnatal outcomes in fetuses demonstrating prenatal imaging findings of persistent extreme hyperextension of the neck. A retrospective cohort of fetuses with extreme fetal neck hyperextension on prenatal ultrasound and subsequent MRI is described. Persistent extreme neck hyperextension was demonstrated in four pregnancies. One patient showed resolution of head positioning prior to labor. In the other 3 patients, neck hyperextension persisted until labor. In these three pregnancies, caesarean section with early intubation was performed due to concern for airway compromise and cervical cord injury. An underlying structural neck abnormality with airway compromise was noted only in 1 patient (large venolymphatic malformation). No airway compromise, cervical spine, or spinal cord anomaly was identified in the remaining 3 patients. Noncervical fetal anomalies were detected only in 1 patient (arthogryposis multiplex and clubfoot deformities). In patients with no structural neck abnormality, early extubation was performed shortly following labor. Detailed, high-resolution fetal MRI may serve as a valuable secondary imaging modality for clinical decision making regarding management of pregnancy, in utero therapy, mode of delivery, and postnatal care.

Rationale and design of the Edwards SAPIEN-3 periprosthetic leakage evaluation versus Medtronic CoreValve in transfemoral aortic valve implantation (ELECT) trial : Arandomised comparison of balloon-expandable versus self-expanding transcatheter aortic valve prostheses.

Background and objectivesPeriprosthetic aortic regurgitation (PPR) after transcatheter aortic valve implantation (TAVI) remains an important issue associated with impaired long-term outcomes. The current randomised study aims to evaluate potential differences between the balloon-expandable Edwards SAPIEN-3 and the self-expanding Medtronic CoreValve system with the main focus on post-TAVI PPR by means of novel imaging endpoints, and an additional focus on other clinical endpoints.EndpointsThe primary endpoint of this study is quantitative assessment of the severity of post-procedural PPR using cardiac magnetic resonance imaging. Several other novel imaging modalities (X-ray contrast angiography, echocardiography) are used as secondary imaging modalities for the assessment of PPR following TAVI. Secondary objectives of the study include clinical outcomes such as cerebral and kidney injury related to TAVI, and quality of life.Methods and designThe ELECT study is a single-centre, prospective, two-armed randomised controlled trial. For the purpose of this study, 108 consecutive adult patients suitable for transfemoral TAVI will be randomly allocated to receive the SAPIEN-3 (n = 54) or the CoreValve system (n = 54).DiscussionThe ELECT trial is the first randomised controlled trial to quantitatively compare the extent of post-TAVI PPR between the SAPIEN-3 and CoreValve. Furthermore, it will evaluate potential differences between the two prostheses with regard to mid-term clinical outcome and quality of life.

Brain Tumors: Epidemiology and Current Trends in Treatment

Background: Brain tumors represent a group of neoplasms arising from brain tissue, each with their own unique biology, prognosis, and treatment. Included in this group are neoplasms not arising from brain parenchyma, which encompass meningiomas, lymphomas, and metastatic disease from other primary sources (often referred to as secondary brain tumors). Despite the diverse group of neoplasms represented, most intracranial tumors follow similar clinical presentations and diagnostic workups. Methods: This review focuses on primary and secondary brain tumor epidemiology, imaging, and treatment modalities. In addition, we will highlight molecular genetic advances in the field that will help shape future treatment approaches. Results: Although tumors affecting the Central Nervous System (CNS) are relatively uncommon, they are often very difficult to treat and cause disproportionate morbidity and mortality. Many of these neoplasms are universally fatal and our ability to treat both benign and malignant tumors is still in its infancy. Our lack of effective treatment leaves many of our patients with few options. Conclusions: The combination of poor prognosis and lack of therapeutic options make further innovation and investigation a priority to improve clinical outcomes for patients suffering from CNS malignancies.

Do additional imaging studies change operative management in patients undergoing adrenalectomy?

The purpose of this study is to determine the incidence of a secondary imaging modality (SIM) in the workup of adrenal masses and the usefulness of this additional imaging in changing surgical management. A retrospective analysis of our adrenalectomy database was performed on adult patients who underwent ≥1 imaging study before surgery. A multivariate logistic regression model was then constructed to identify patient factors that predisposed SIM. From February 2001 to August 2014, 264 cases met inclusion criteria, of which 98 (37%) were identified to have SIM. Patients with cancer (P = .001), incidentaloma (P = .002), and pheochromocytoma (P < .0001) were more likely to undergo additional imaging. MRI was the most commonly obtained SIM. In addition, 90 of the 98 cases (92%) met indications for adrenalectomy with primary imaging study and biochemical screening alone. Of the remaining 8 cases, in only 4 instances (4%) did SIM modify surgical decision making. The high incidence of unnecessary additional imaging performed in patients undergoing adrenalectomy is counterproductive to efforts toward cost-conscious, high-quality health care. Patients with adrenal tumors would benefit from early surgical referral to allow the surgeon to help guide clinical decision making and to avoid the use of excessive imaging.

Role of MRI for detection and characterization of pulmonary nodules

Due to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions. The purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character. The MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted.

Clinical Efficacy of FDG‐PET/CT in Head and Neck Adenoid Cystic Carcinomas

Objective: Positron emission tomography/computed tomography (PET/CT) with fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) of salivary malignancies is variable, thus unreliable for staging/surveillance. For adenoid cystic carcinomas (ACC), data is limited regarding FDG uptake. The objective is to characterize PET/CT and its ability to detect primary disease/tumor recurrence in patients with head and neck ACCs (HNACCs). Method: Ten-year retrospective study of 25 patients diagnosed with HNACCs. Eleven patients (8 women; age 33-65 years at time of diagnosis) were referred for whole-body FDG-PET/CT. Secondary imaging modalities were also acquired. Fifteen tumor sites (primary and metastatic foci) were evaluated. Histological disease was confirmed by biopsy and surgical pathology. Results: Of those referred for PET/CT, 81.8% (9/11) had primary disease foci detected and 22.2% (2/9) had distant metastasis. In one patient with metastatic disease, cavernous sinus disease was detected on MRI and not appreciated on PET/CT but was consistent with MRI in detecting disease foci of the nasal dorsum and lung. In one patient with base of the tongue ACC, PET/CT accurately detected cervical lymph nodes suspicious for malignancy not detected on CT scan. On MRI, another patient treated for nasal cavity ACC had what appeared to be disease recurrence, not appreciated on PET/CT and was confirmed as a pyogenic granuloma. Conclusion: In HNACCs, FDG-PET/CT is useful for preoperative evaluation of initial/recurrent disease foci and disease staging for treatment strategy; thus it shouldn’t be excluded as a method of patient evaluation.

Breast Imaging Devices for Nuclear Medicine

Breast cancer has long been a significant cause of morbidity and mortality. Mammography is the first-line imaging examination used to detect breast cancer; it has high sensitivity but only moderate specificity. The currently used secondary imaging modalities, sonography and MRI, cannot weed out all the false-positive lesions that mammography identifies as potentially malignant. Further, many patients do not image well on mammography, so there is a significant need for alternative imaging methods. Recently, technologies using small-field, pixelated detectors optimized for breast imaging have become available for both single-photon-emitting and positron-emitting radiopharmaceuticals. This article addresses the construction and functionality of several detector types and their application to imaging of the breast. Technical aspects of nuclear breast imaging will be discussed briefly. The article concludes with an assessment of the position of nuclear medicine imaging of the breast within the overall diagnostic scheme for breast cancer detection.

Flowable resin and marginal gap on tooth third medial cavity involving enamel and radicular cementum: A SEM evaluation of two restoration techniques

The aim of this study is to investigate the presence and the extent of a possible marginal gap after the interposition of a flowable composite between the composite restoration and the dental structures (enamel and cementum). This technique is also used to eliminate the infiltration in a zone of the cavity preparation that is frequently at a risk of secondary decay. Fifteen human premolars extracted for orthodontic reasons were used for the study. A cavity with mesial and distal margin in enamel and cementum was realized in every tooth. The cavities were then restored with an adhesive system (ScotchBond 3MÔ) and composite (Filtek Supreme 3MÔ); and, a fine layer of flowable composite was applied in the distal margin of each cavity. Scanning electron microscopy (SEM) in secondary electron imaging (S.E.I.) modality was used for the study and identifying the marginal gaps in the composite restorations. Data was investigated on the mesial and distal margin of each cavity at the restoration-enamel interface, and at the restoration-cementum interface. The interfaces were divided in four groups: Group A (enamel/composite); Group B (enamel/flow/composite); Group C (cementum/composite); and, Group D (cementum/flow/composite). By the comparison of the gap's average width found in each group, it is evidenced that the average width of the gap increases when the interface moves from the coronal to the radicular end (Group A 0,1 ± 0,4 μm Vs Group C 12,3 ± 11,6 μm; Group B 0,2 ± 0,8 μm Vs Group D 2,8 ± 6,6 μm). Correlating the measurements of the marginal gap's average width among the Group A and Group B, no significant variations were obtained; and instead, on comparing Group C with Group D, the gap's average width decreases. The interposition of a low elastic modulus composite between the adhesive layer and the composite resin allows an improvement of the cementum-restoration interface by the means of a lower shrinkage stress during polymerization.

Bilateral knee lipoma arborescence diagnosed by ultrasound

Dear Editor, A 57-year-old Hispanic woman with no significant past medical history, presented to our clinic with a 5-year history of bilateral knee pain and swelling for which she had tried naproxen without much relief. Physical examination revealed a moderate effusion in the right supra-patellar region with a limited range of motion from 0° up to 100°. The left knee effusion was milder and range of motion was preserved. Laboratory tests demonstrated a normal leukocyte count, C-reactive protein and erythrocyte sedimentation rate. Furthermore, synovial fluid analysis was non-inflammatory without any crystals. Rheumatoid factor (RF) was 31 IU/mL (normal < 13.9) but anti-cyclic citrulinated protein (anti-CCP) was negative. Radiographs of right knee demonstrated a moderate knee effusion without erosions. Radiographs of bilateral hands demonstrated joint space narrowing and osteophytes along both the first metacarpophalangeal joints consistent with osteoarthritis. Ultrasound of bilateral knees revealed a villous hyperechoic fatty proliferation with clear frond-like morphology inside the pouch, consistent with lipoma arborescens, more prominent in the right knee (Fig. 1). MRI of the right knee demonstrated suprapatellar joint effusion and frond-like projections of hypertrophied synovium (Fig. 2). Although positive for RF, the patient did not have any signs of active synovitis and hence was referred to orthopedic surgery for synovectomy. Longitudinal view, 7.5–12 MHz ultrasound image of both knees over suprapatella recess demonstrates a large effusion and villous hyper-echoic fatty synovial proliferation with clearly frond-like morphology inside the pouch. Sagittal T2-weighted image with fat saturation of the knee demonstrates a large suprapatellar joint effusion. Frond-like projections of hypertrophied synovium extend into the high-signal joint fluid. The signal intensity of the frond-like projections is identical to the subcutaneous fat. Discrete intra-articular solid lipomas are very rare; the more common finding is lipoma arborescens which represents a diffuse fatty lesion of the joint.1 A characteristic gross feature is an increased level of mature fat cells, which proliferate under the synovium, producing excess pressure on the synovial lining which leads to bulges which appear as multiple villi-like morphologies.2 At the cellular level, there are sheets of mature adipocytes, which are mixed with vasculature and separated by fibrous septae.2 The main differential diagnosis to consider in this scenario is pigmented villonodular synovitis. On ultrasound, pigmented villonodular synovitis (PVNS) presents as a well-delinated hypo-echoic mass inside the Hoffa fat pad (infra-patellar fat pad); in contrast lipomatosis arborescence presents as a hyperechoic frond-like lesion. On MRI PVNS exhibits low signal on both T1- and T2-weighted sequences due to hemosiderine deposites in the synovium. These lesions manifest various clinical symptoms depending on location and extent of fat proliferation. However, chronic intermittent effusions, edema and limited range of motion in the affected joint are common manifestations.1, 2 Although the most common location for this entity is in the suprapatellar region of the knee, there have been case reports of a multitude of other joints affected, such as wrists, hips, ankles, glenohumeral joints and tendon sheaths.2-5 Although there have been multiple lipomatosis arborescens cases which are classified as secondary to an underlying pathology such as RA, DJD or trauma, there are also cases without any underlying reactive process.1, 6 Hence, the underlying trigger for the proliferation of these fat cells under the synovial lining is yet to be elucidated. Radiographic features include a soft tissue mass within the synovium and occasionally along with degenerative findings.1, 7 On MRI the villi formed by the synovial mass appear as frond-like structures and the signal intensity of the villi resembles fat.1, 5, 7 Characteristic sonographic findings demonstrate an effusion along with a hyper-echoic synovial mass with villi, which demonstrate wave-like motility upon compression via ultrasound probe.7 We believe this case is among the few unique cases of lipomatosis arborescens found to occur in a bilateral distribution. Furthermore, this is the first time that this entity has been diagnosed primarily via ultrasound and only confirmed by MRI as a secondary imaging modality. When considering lipomatosis arborescens in the differential diagnosis, utilizing ultrasound as the first diagnostic imaging modality, is a quick, inexpensive and reliable method to make the diagnosis, given unique and characteristic sonographic features of this entity.

Clinical utility of tomosynthesis in suspected scaphoid fracture. A pilot study

Radiography alone will not detect all scaphoid fractures. There is a reported prevalence between 9 and 33% of occult scaphoid fractures. The evidence-based literature suggests that magnetic resonance imaging (MRI) is the most suitable secondary imaging modality due to the ability to evaluate the bone marrow directly and to also identify other injuries. However, there is no consensus on the choice of follow-up imaging strategy-computed tomography, MRI, or bone scan-across different institutions. Tomosynthesis is a new digital tomographic method creating multiple thin tomographic sections. The purpose of this study was to evaluate the clinical utility of tomosynthesis in suspected occult fracture. Thirty-five patients with a clinically suspected occult scaphoid fracture after initial normal radiography were imaged with repeat radiography and tomosynthesis scan 2weeks after trauma. Repeat radiography revealed one previously undetected scaphoid tubercle avulsion and one scaphoid waist fracture, confirmed by tomosynthesis. Tomosynthesis revealed two additional scaphoid waist fractures. In total, three initially occult scaphoid waist fractures were detected (9%). No additional fractures were detected in the remaining 32 patients during a 1-year follow-up. Tomosynthesis can demonstrate occult scaphoid fractures not visible at radiography.

Data Specific Spatially Varying Regularization for Multimodal Fluorescence Molecular Tomography

Fluorescence molecular tomography (FMT) allows in vivo localization and quantification of fluorescence biodistributions in whole animals. The ill-posed nature of the tomographic reconstruction problem, however, limits the attainable resolution. Improvements in resolution and overall imaging performance can be achieved by forming image priors from geometric information obtained by a secondary anatomical or functional high-resolution imaging modality such as X-ray computed tomography or magnetic resonance imaging. A particular challenge in using image priors is to avoid the use of assumptions that may bias the solution and reduced the accuracy of the inverse problem. This is particularly relevant in FMT inversions where there is not an evident link between secondary geometric information and the underlying fluorescence biodistribution. We present here a new, two step approach to incorporating structural priors into the FMT inverse problem. By using the anatomic information to define a low dimensional inverse problem, we obtain a solution which we then use to determine the parameters defining a spatially varying regularization matrix for the full resolution problem. The regularization term is thus customized for each data set and is guided by the data rather than depending only on user defined a priori assumptions. Results are presented for both simulated and experimental data sets, and show significant improvements in image quality as compared to traditional regularization techniques.

Diagnostic management of clinically suspected acute deep vein thrombosis

Deep vein thrombosis (DVT) is a common disease that may lead to potentially fatal complications, such as pulmonary embolism. In the past decades several diagnostic tools and algorithms for DVT have been studied. Currently the combination of a clinical decision rule, D-dimer testing and compression ultrasonography has proved to be safe and effective for the diagnosis of DVT in the lower extremities. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) can be useful as additional or secondary imaging modalities. This review will discuss the elements currently used in making the clinical diagnosis of DVT. These elements include clinical decision rules and D-dimer testing, different imaging investigations and the appropriate use of these within diagnostic algorithms in patients with clinically suspected DVT. Although current knowledge of the options available to diagnose DVT of the lower extremities is well established, there are still unresolved issues, including the optimal diagnosis of recurrent DVT and distal DVT. Furthermore, the diagnosis of DVT of the upper extremities will be discussed, including the different imaging modalities and the limitations of these techniques.

1401: Cystic Lesions of the Pancreas: Ultrasound Differential Diagnosis

Ultrasonography (US) renders a direct access to pancreatic morphology. Resolution capabilities of US are not achieved by the secondary imaging modalities (computed tomography and magnetic resonance), and the realtime information in US examination are not available by other modalities either. These unique features of US hold true as well in cystic pancreatic lesions of benign or of malignant origin. Descriptive criteria such as size, number, shape, echogenicity, position, texture, septations and wall structures give valuable information for an as clear a diagnostic classification as possible.

Imaging of Vx‐2 rabbit tumors with ανβ3‐integrin‐targeted 111In nanoparticles

Earlier tumor detection can improve 5-year survival of patients, particularly among those presenting with cancers less than 1 cm in diameter. alpha(nu)beta(3)-Targeted (111)In nanoparticles (NP) were developed and studied for detection of tumor angiogenesis. Studies were conducted in New Zealand white rabbits implanted 12 days earlier with Vx-2 tumor. alpha(nu)beta(3)-Targeted (111)In/NP bearing approximately 10 (111)In/NP vs. approximately 1 (111)In/NP nuclide payloads were compared to nontargeted radiolabeled control particles. In vivo competitive binding studies were used to assess ligand-targeting specificity. alpha(nu)beta(3)-Integrin-targeted NP with approximately 10 (111)In/NP provided better (p < 0.05) tumor-to-muscle ratio contrast (6.3 +/- 0.2) than approximately 1 (111)In/NP (5.1 +/- 0.1) or nontargeted particles with approximately 10 (111)In/NP (3.7 +/- 0.1) over the initial 2-hr postinjection. At 18 hr, mean tumor activity in rabbits receiving alpha(nu)beta(3)-integrin-targeted NP was 4-fold higher than the nontargeted control. Specificity of the NP for the tumor neovasculature was supported by in vivo competition studies and by fluorescence microscopy of alpha(nu)beta(3)-targeted fluorescent-labeled NP. Biodistribution studies revealed that the primary clearance organ in rabbits as a %ID/g tissue was the spleen. Circulatory half-life (t(1/2)beta) was estimated to be approximately 5 hr using a 2-compartment model. alpha(nu)beta(3)-Targeted (111)In perfluorocarbon NP may provide a clinically useful tool for sensitively detecting angiogenesis in nascent tumors, particularly in combination with secondary high-resolution imaging modalities, such as MRI.

A 53-year-old woman with a leiomyosarcoma of the breast

In this day and age of mammographic screening, increased awareness of breast cancer, and more accurate secondary imaging modalities such as ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET), one would think advanced breast cancer would become a thing of the past. It hasn’t, and caring for such patients doesn’t always follow in a straightforward fashion. We present a case of a breast leiomyosarcoma and discuss management and therapy of these unusual neoplasms.

MAGNETIC RESONANCE IMAGING OF THE CHEST: Where We Stand

Although the improved soft tissue contrast, multiplanar capacity, intrinsic flow sensitivity, and lack of ionizing radiation make MR an ideal thoracic imaging modality, technical problems resulting from magnetic susceptibility effects and motion have significantly limited its application. Currently, with the exception of cardiovascular applications and assessment of Pancoast tumors, MR remains a secondary imaging modality to chest CT. Research into thoracic MR undoubtedly will expand the current clinical indications. Development of specialized pulse sequences to address the unique problems of MR in the thorax will improve image quality and expand its clinical role. Additionally, MR provides unique information not easily obtainable by other noninvasive imaging modalities, such as quantitative determination of lung water. Further research in this area may provide unique insights into the pathophysiology of chronic interstitial lung disease. As a result, the role of thoracic MR should change significantly by the turn of the century.

A Computerized System for the Elastic Matching of Deformed Radiographic Images to Idealized Atlas Images

A system of computer programs is described which, for the first time, is able to use computerized tomographic data to automatically locate, measure, and describe anatomical structures of interest with accuracy and consistency. Input to the system consists of any digitized radiographic data. Computer assisted tomographic (CAT) scans of the head were used in this first implementation. Using these data and a predefined atlas picture representing an idealized view of the average normal image, an individualized atlas was created. From the individualized atlas, structure size, density, location displacement, and distortion may be calculated. The individualized atlas created using high resolution data, such as the CAT scan, may then be directly superimposed on pictures obtained using lower resolution modalities, such as positron emission tomographic scan images. This allows the precise location of structures poorly visualized by the secondary imaging modality. This system is capable of using either two- or three-dimensional data.