Iliac vein compression syndrome: Clinical,imaging and pathologic findings

May-Thurner syndrome (MTS) is the pathologic compression of the left common iliac vein by the right common iliac artery, resulting in left lower extremity pain, swelling, and deep venous thrombosis. Though this syndrome was first described in 1851, there are currently no standardized criteria to establish the diagnosis of MTS. Since MTS is treated by a wide array of specialties, including interventional radiology, vascular surgery, cardiology, and vascular medicine, the need for an established diagnostic criterion is imperative in order to reduce misdiagnosis and inappropriate treatment. Although MTS has historically been diagnosed by the presence of pathologic features, the use of dynamic imaging techniques has led to a more radiologic based diagnosis. Thus, imaging plays an integral part in screening patients for MTS, and the utility of a wide array of imaging modalities has been evaluated. Here, we summarize the historical aspects of the clinical features of this syndrome. We then provide a comprehensive assessment of the literature on the efficacy of imaging tools available to diagnose MTS. Lastly, we provide clinical pearls and recommendations to aid physicians in diagnosing the syndrome through the use of provocative measures.     

Magnetic resonance imaging of the spine at 3 Tesla

Magnetic resonance imaging (MRI) has developed dramatically in the 25 years since its clinical introduction. Advances in hardware design have included the development of high field magnets and more sophisticated and sensitive coils. Improvements in sequences, data sampling, and postprocessing software have benefited the attainable spatial and temporal resolution to the point at which the fine depiction of anatomical structure and pathological processes is now routine. As in other radiological areas, the most recent advances in MRI have proven highly valuable in the field of musculoskeletal radiology where the lack of radiation, high soft tissue contrast, and capacity for multiplanar or three-dimensional imaging have made MRI the imaging modality of choice. Particular benefits are seen in diagnostic imaging of the spine where MRI is clearly superior to both conventional radiography and computed tomography. In this article, we discuss the impact of the most recent technological advance in MRI, namely the advent of 3 Tesla (3-T) imaging, on diagnostic imaging of the spine. Comparisons are drawn with imaging at 1.5 T, and emphasis is placed on MR physics and on the benefits and principal difficulties associated with spine imaging at high field strength.     

Turf wars in radiology: the overutilization of imaging resulting from self-referral

A recent report by the Medicare Payment Advisory Commission to Congress indicated that the utilization of diagnostic imaging is growing more rapidly than that of any other type of physician service. This has engendered concern among those who pay for health care. In this article, the authors review the role of self-referral in driving up imaging utilization.A number of studies of the self-referral factor in imaging have been conducted over the past three decades. These have consistently shown that when nonradiologist physicians operate their own imaging equipment and have the opportunity to self-refer, their utilization is substantially higher than among other physicians who refer their patients to radiologists. It has also been shown that the vast bulk of the recent increases in imaging utilization are attributable to nonradiologists who self-refer. The authors estimate that the cost to the American health care system of unnecessary imaging resulting from self-referral by nonradiologists is $16 billion per year.     

Magnetic resonance imaging or arthrography for shoulder problems: a randomised study

Objective: Diagnostic technologies are often assessed merely by their accuracy, rather than by their impact on diagnosis and patient management. To this end the authors have undertaken a study to assess the diagnostic and therapeutic impact of magnetic resonance imaging (MRI) and arthrography of the shoulder for patients referred from a rheumatology clinic. Methods and patients: Patients referred from a rheumatology clinic with symptoms warranting imaging of the shoulder were randomised to either MRI or arthrography. Data on the clinician’s diagnostic confidence and management were recorded before and after imaging using questionnaires. Patients were followed-up at least 10 months after imaging to see how management plans evolved, and what proportion of patients required further imaging. Results: Fifty three shoulders underwent imaging over a year and entered into the study; 29 randomised to MRI and 24 to arthrography. Both MRI and arthrography had a similar beneficial diagnostic impact in terms of clinical diagnoses (refuted and retained) and new diagnoses established. MRI and arthrography had a similar therapeutic impact, although MRI was associated with a significant shift towards surgical intervention. Conclusion: MRI and arthrography a have similar diagnostic and therapeutic impact.     

Planar ventilation-perfusion imaging for pulmonary embolism: the case for "outcomes" medicine

Single-photon emission computed tomography (SPECT) has been a significant advancement in scintigraphy, impacting many areas of diagnosis. It has begun to find use in ventilation-perfusion (V/Q) scintigraphy. However, its utility has been limited in the United States because of a lack of an optimal and Food and Drug Administration-approved SPECT ventilatory agent. Although SPECT V/Q can show more and smaller mismatches than planar studies, there is persistent debate regarding the clinical significance of these smaller pulmonary emboli (PE); they may be neither clinically significant nor require treatment. Available data suggest that planar V/Q, SPECT V/Q, and computed tomographic pulmonary angiography (CTPA) have similar false-negative rates and thus have a similar impact on outcomes. In most cases, emergency department physicians are the first to encounter patients who may have PE, and they frequently use an imaging study as part of the evaluation. We discuss the rational for triaging patients to different imaging modalities with the use of chest radiography and the strengths and weaknesses of each modality. Detailed anatomy is an advantage of CTPA, breast radiation dose is reduced with scintigraphy, and imaging is quicker and more detailed with SPECT. We also review planar and SPECT V/Q and CTPA from the differing vantage points of diagnostic accuracy vs patient outcomes. Whatever modality their patients require, physicians can be confident that they are all similarly efficacious at diagnosing clinically relevant emboli.     

Fast MR imaging of fetal CNS anomalies in utero

BACKGROUND AND PURPOSE: Although sonography is the primary imaging technique for evaluating the developing fetus, significant limitations exist in the sonographic prenatal diagnosis of many brain disorders. Fast MR imaging is increasingly being used to determine the underlying cause of nonspecific fetal CNS abnormalities detected sonographically and to confirm or provide further support for such anomalies. Our goal was to determine the value of MR imaging in establishing the diagnosis of fetal CNS anomalies, to ascertain how this information might be used for patient counseling, and to assess its impact on pregnancy management. METHODS: We prospectively performed MR examinations of 73 fetuses (66 pregnancies) with suspected CNS abnormalities and compared these with available fetal sonograms, postnatal images, and clinical examinations. Retrospectively, the impact on patient counseling and pregnancy management was analyzed. RESULTS: Images of diagnostic quality were routinely obtained with in utero MR imaging, which was particularly valuable in detecting heterotopia, callosal anomalies, and posterior fossa malformations, and for providing excellent anatomic information. We believe that 24 (46%) of 52 clinical cases were managed differently from the way they would have been on the basis of sonographic findings alone. In every case, the referring physicians thought that MR imaging provided a measure of confidence that was not previously available and that was valuable for counseling patients and for making more informed decisions. CONCLUSION: Sonography is the leading technique for fetal assessment and provides reliable, inexpensive diagnostic images. Fast MR imaging is an important adjunctive tool for prenatal imaging in those instances in which a complex anomaly is suspected by sonography, when fetal surgery is contemplated, or when a definitive diagnosis cannot be determined.     

The current role of imaging techniques in faecal incontinence

Faecal incontinence is a common multifactorial disorder. Major causes of faecal incontinence are related to vaginal delivery and prior anorectal surgery. In addition to medical history and physical examination, several anorectal functional tests and imaging techniques can be used to assess the underlying pathophysiology and to guide treatment planning in faecal incontinent patients. Anorectal functional tests provide functional information, but the potential strength comes from combining test results. Imaging techniques, including defecography, endoanal sonography, and magnetic resonance (MR) imaging, provide structural information about the anorectal region with a direct clinical impact. The major role of imaging techniques in faecal incontinence is visualising the structural and functional integrity of the anal sphincter complex. Both two-dimensional endoanal sonography and endoanal MR imaging are accurate tools to depict anal sphincter defects. The major advantage of endoanal MR imaging is the accurate demonstration of external anal sphincter atrophy. Recent studies have suggested that external phased array MR imaging and three-dimensional endoanal sonography are also valuable tools in the diagnostic work up of faecal incontinence. Decisions about the preferred technique will mainly be determined by availability and local expertise. This article demonstrates the current role of tests, predominantly imaging tests, in the diagnostic work up of faecal incontinence.     

Utilization of diagnostic medical imaging: comparison of radiologist referral versus same-specialty referral

PURPOSE: To retrospectively compare the frequency with which patients underwent diagnostic medical imaging procedures during episodes of outpatient medical care according to whether their physicians referred patients for imaging to themselves and/or physicians in their same specialty or to radiologists. MATERIALS AND METHODS: Institutional review board approval was not necessary for this HIPAA-compliant study. An insurance claims database from a large national employer-based health plan was obtained. Claims data from 1999-2003 were grouped into episodes of care for six conditions: cardiopulmonary disease, coronary and/or cardiac disease, extremity fracture, knee pain, intraabdominal malignancy, and stroke. For each condition, each referring physician's behavior was categorized as either "same-specialty referral" or "radiologist referral" on the basis of that physician's entire history of imaging referrals for the condition. The frequency with which patients underwent diagnostic medical imaging procedures during episodes of care was compared according to whether their physicians referred patients for imaging to themselves and/or same-specialty physicians or to radiologists. Rates were compared by using chi(2) tests, and logistic regression was used to compare utilization rates, with patient age and number of comorbidities as covariates. RESULTS: For the conditions evaluated, physicians who referred patients to themselves or to other same-specialty physicians for diagnostic imaging used imaging between 1.12 and 2.29 times as often, per episode of care, as physicians who referred patients to radiologists (P < .005 for all comparisons). Adjusting for patient age and comorbidity, the likelihood of imaging was 1.196-3.228 times greater for patients cared forby same-specialty-referring physicians. CONCLUSION: Same-specialty-referring physicians tend to utilize imaging more frequently than do physicians who refer their patients to radiologists. These results cannot be explained by differences in case mix (because analyses were performed within six specific conditions of interest), patient age, or comorbidity.     

Breast magnetic resonance imaging

Mammography has long been considered the gold standard for screening breast cancer. Although it reduces the risk of breast cancer mortality by enabling early diagnosis, it does not detect all breast cancers. Numerous breast imaging technologies are emerging as effective adjunctive diagnostic tools when mammography results are negative or inconclusive. Contrast-enhanced magnetic resonance (CE-MR) imaging, in particular, has demonstrated a high sensitivity and has proven to be most effective, especially with patients at high risk for developing breast cancer. This article discusses the clinical applications for breast MR imaging, use of CE-MR for breast cancer detection, and other emerging breast imaging technologies.     

The choice of the correct imaging modality in breast cancer management

This brief overview discusses which of the diagnostic options are more reliable and effective for breast cancer imaging with a view to avoiding the unjustified use of techniques that are suboptimal. The technological development of diagnostic imaging has been very impressive, and both radiological (mammography, ultrasonography, computed tomography, magnetic resonance imaging) and nuclear medicine tools (bone scan, planar and SPECT scintigraphy, sentinel node biopsy, positron emission tomography) have helped to overcome past limitations in the detection of small lesions. Furthermore, new approaches have been developed that permit successful differential diagnosis of doubtful lesions and rapid identification of systemic metastases, and allow non-invasive characterisation of the biology of cancer tissue. There is evidence that these advances may have helped in optimising therapeutic strategies. Importantly, the metabolic information provided by nuclear medicine procedures may be combined with the anatomical data supplied by radiological techniques in order to assist in predicting tumour response, planning radiotherapy and monitoring patient outcome. It is difficult to formulate conclusive diagnostic guidelines for application in the work-up of breast cancer, because while the role of some examinations, such as mammography and ultrasonography, is well established, that of others, such as magnetic resonance imaging and positron emission tomography, is still a matter of debate. There is a need for further prospective evaluations with appropriate clinical trials designed to evaluate the impact of these approaches in improving survival and quality of life.     

Magnetic resonance imaging of the knee.

Magnetic resonance imaging (MRI) has revolutionised diagnostic imaging of the knee. It has evolved significantly since Kean described healthy and pathologic knee anatomy in 1983. This innovative technology allows superior soft-tissue detail with multiplanar imaging capability that provides accurate evaluation of intra- and extra-articular structures of the knee not demonstrated with other imaging modalities. The development and advancements in MRI and the introduction of high-resolution coils have provided a noninvasive, nonoperator dependent, cost effective means to diagnose knee pathology. MRI is well tolerated by patients, widely accepted by evaluating physicians, and assists in distinguishing pathologic knee conditions that may have similar clinical signs and symptoms (i.e. meniscal tears, osteochondral lesions). This paper presents an overview of MRI of the knee and focuses on the MRI findings in a number of common pathologic conditions.     

Whole body MR imaging in diabetes

Diabetes mellitus is a major cardiovascular risk factor and one of the major causes for morbidity and mortality worldwide. Diabetic complications have not only major impact on the quality of life of diabetic patients, but are also potentially life-threatening. Therefore prevention, diagnosis and therapy of these long-term complications are of high importance. However, diagnosis of the variety of complications from diabetes mellitus remains a diagnostic challenge and usually several diagnostic steps are necessary to diagnose or exclude these complications.In the last years whole body magnetic resonance imaging (WB-MRI) including whole body magnetic resonance angiography (WB-MRA) has been introduced for cardiovascular imaging and is now increasingly applied in clinical routine for the workup of patients with cardiovascular disease and for cardiovascular screening. The article summarizes rationales for WB-MRI in diabetes mellitus, technical concepts of disease specific cardiovascular WB-MRI in diabetes mellitus and discusses potential clinical consequences.     

Impact of bedside right upper quadrant ultrasonography on radiology imaging

Many Emergency Departments (ED) use emergency ultrasonography of the right upper quadrant (RUQ) to capture images of the gallbladder in patients with suspected gallstones. It is unclear what impact this practice has on additional imaging performed by radiology. Patients were enrolled 24 h a day by ED residents and attending physicians who have completed an educational program in limited RUQ ultrasound. All ultrasounds were videotaped and later reviewed. According to the American College of Emergency Physicians’ credentialing standards, 25 ultrasounds were required before using the results clinically. A total of 352 patients were enrolled by 42 physicians over a 1-year period. Two hundred twelve (60.2%) of the ultrasounds were performed clinically, with the rest performed for teaching purposes. One hundred seventy-nine (50.9%) of the ultrasounds were performed by credentialed physicians. One hundred forty-nine (70%) clinical and 29 (20.7%) teaching ultrasounds had additional imaging. The average time to follow up imaging after discharge from the ED was 8.51 days. Most patients receiving emergency ultrasound of their RUQ had follow-up imaging by radiology.     

Diffusion-weighted MR imaging of the spinal cord

Diffusion-weighted MR imaging may increase the sensitivity and specificity of MR imaging for certain pathologic conditions of the spinal cord but is rarely performed because of several technical issues. We therefore tested a novel phase-navigated spin-echo diffusion-weighted interleaved echo-planar imaging sequence in seven healthy volunteers and six patients with intramedullary lesions. We performed diffusion-weighted MR imaging of the spinal cord with high spatial resolution. Different patterns of diffusion abnormalities observed in patient studies support the possible diagnostic impact of diffusion-weighted MR imaging for diseases of the spinal cord.     

Cardiovascular imaging: who does it and how important is it to the practice of radiology?

OBJECTIVE: Our research was conducted to ascertain the importance of noninvasive cardiovascular imaging to the practice of radiology and to determine what percentages of noninvasive cardiovascular imaging are performed by radiologists and by other types of physicians. MATERIALS AND METHODS: Using the national 1998 Medicare Part B database, we reviewed all 460 procedure codes pertaining to noninvasive diagnostic imaging and identified 65 that were specifically related to the cardiovascular system. These 65 codes were grouped in five categories: cardiac MR imaging, MR angiography, cardiovascular nuclear medicine, echocardiography, and vascular sonography. For each code and category, we determined the nationwide examination volume, the utilization rate per 1,000 Medicare fee-for-service enrollees, Part B physician reimbursements, and the percentages of examinations performed by radiologists, cardiologists, surgeons, and other physicians. RESULTS: During 1998, 19,244,001 noninvasive cardiovascular imaging studies were performed on Medicare enrollees, which accounted for 17.7% of all Medicare diagnostic imaging studies carried out that year and 33.6% of all Part B imaging-related reimbursements paid. The utilization rate for noninvasive cardiovascular imaging was 603 per 1,000 Medicare enrollees per year. Echocardiography alone accounted for 63.4% of these examinations. Radiologists conducted 16.7% of all noninvasive cardiovascular imaging, whereas cardiologists conducted 61.5%, surgeons 4.8%, and other physicians 16.9% of the examinations. The strong role of cardiologists was largely attributable to their dominance in echocardiography. Radiologists had a substantial role in all categories except echocardiography. CONCLUSION: Noninvasive cardiovascular imaging represents an important component of the practice of radiology. Radiologists have substantial participation in all aspects of the field with the exception of echocardiography.     

Anticipatory anxiety and interpersonal relations with the radiologist of patients undergoing diagnostic imaging]

A pilot study has been carried out with the aim of evaluating the impact of updated imaging techniques (CT and MRI) versus "simple" examinations (tomography, X-rays, US, and nuclear medicine) on the anticipatory anxiety of the patients, as well as on the radiologist-patient relationship. Ninety consecutive patients undergoing diagnostic imaging modalities were examined according to the following schedule: 1) preliminary interview and anxiety assessment according to HRSA; 2) diagnostic imaging investigation, and 3) filling out an "ad hoc" questionnaire. The collected data have been divided into two groups: the "simple" group (52 patients submitted to X-rays, tomography, US, and nuclear medicine), and the "complex" group (38 patients submitted to CT and MRI). Anticipatory anxiety was observed in all subjects and attained psychopathological rates in more than half of them. Anxiety proved to be related to the completion of the examination rather than to its complexity. The questionnaire has pointed out the need for a more interactive relationship between radiologist and patient during diagnostic imaging examinations.     

Optimisation of statistical methodologies for a better diagnosis of neurological and psychiatric disorders by means of SPECT

In the last years there has been a wide consensus on the importance of brain imaging in assessing neurodegenerative and psychiatric disorders. Different techniques for functional and anatomical examination are currently clinically implemented in neurology and psychiatry to improve sensitivity, specificity and accuracy of the diagnosis of various diseases. In addition, the increasing life expectancy in the Western world raises the social importance and the economical impact of age-related neurodegenerative disorders since the incidence of Alzheimer disease and Parkinson disease is higher in the elderly. An early diagnosis of neuro-psychiatric diseases and the assessment of "natural" changes of regional cerebral blood flow (rCBF) distribution during normal aging are hence of utmost importance. In the recent past brain disorders have extensively been investigated by means of optimised nuclear medicine techniques, instruments and algorithms. Diagnosis can be better achieved by identifying those structures in which CBF or metabolism deviate from normality resulting in significant changes as compared to a reference database. In the present paper we present some studies investigating, by means of recently implemented diagnostic tools, patients bearer of various neuro-psychiatric disorders. The improved nuclear medicine techniques and instrumentation, the state-of-the-art software for brain imaging standardisation and the use of sophisticated multivariate data analysis are extensively reviewed.     

Imaging in radiotherapy

Radiotherapy, more then any other treatment modality, relies heavily and often exclusively on medical imaging to determine the extent of disease and the spatial relation between target region and neighbouring healthy tissues. Radically new approaches to radiation delivery are inspired on CT scanning and treat patients in a slice-by-slice fashion using intensity modulated megavoltage fan beams. For quality assurance of complex 3-D dose distributions, MR based 3-D verificative dosimetry on irradiated phantoms has been described. As treatment delivery becomes increasingly refined, the need for accurate target definition increases as well and sophisticated imaging tools like image fusion and 3-D reconstruction are routinely used for treatment planning. While in the past patients were positioned on the treatment machines based exclusively on surface topography and the well-known skin marks, such approach is no longer sufficient for high-accuracy radiotherapy and special imaging tools like on-line portal imaging are used to verify and correct target positioning. Much of these applications rely on digital image processing, transmission and storage, and the development of standards, like DICOM and PACS have greatly contributed to these applications. Digital imaging plays an increasing role in many areas in radiotherapy and has been fundamental in new developments that have demonstrated impact on patient care.