Prevalence of annular tears and disc herniations on MR images of the cervical spine in symptom free volunteers.

STUDY DESIGN: Prospective MR analysis of the cervical spine of 30 asymptomatic volunteers. OBJECTIVES: To evaluate the prevalence of annular tears, bulging discs, disc herniations and medullary compression on T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance (MR) images of the cervical spine in symptom free volunteers. SUMMARY OF BACKGROUND DATA: Few studies have reported the prevalence of cervical disc herniations in asymptomatic people, none have reported the prevalence of cervical annular tears on MR images of symptom free volunteers. MATERIALS AND METHODS: Thirty symptom-free volunteers (no history or symptoms related to the cervical spine) were examined using sagittal T2-weighted fast spin-echo (SE), sagittal gadolinium-enhanced T1-weighted SE imaging and axial T2(*)-weighted gradient echo (GRE). The prevalence of bulging discs, focal protrusions, extrusions, nonenhancing or enhancing annular tears and medullary compression were assessed. RESULTS: The prevalence of bulging disk and focal disk protrusions was 73% (22 volunteers) and 50% (15 volunteers), respectively. There was one extrusion (3%). Eleven volunteers had annular tears at one or more levels (37%) and 94% of the annular tears enhanced after contrast injection. Asymptomatic medullary compression was found in four patients (13%). CONCLUSION: Annular tears and focal disk protrusions are frequently found on MR imaging of the cervical spine, with or without contrast enhancement, in asymptomatic population. The extruded disk herniation and medullary compression are unusual findings in a symptom-free population.

Sonography of a rupture of the tendon of the extensor pollicis longus muscle: initial clinical experience and correlation with findings at cadaveric dissection.

OBJECTIVE: The objectives of our study were to report our initial clinical experience with sonography of the wrist for diagnosing a proximal rupture of the tendon of the extensor pollicis longus (EPL) muscle and to perform sonographic-anatomic correlation of the EPL tendon. MATERIALS AND METHODS: Clinical and imaging files of five patients who underwent sonography and subsequent open wrist surgery were reviewed retrospectively. Imaging was performed by four radiologists experienced in musculoskeletal sonography. Tendon retraction was evaluated on sonography and at surgery. In cadavers, sonography was performed in concert by two musculoskeletal radiologists during progressive stages of dissection of four embalmed specimens. One specimen was sliced in the transverse plane. RESULTS: In cadavers, the EPL tendon was located on or adjacent to Lister's tubercle and extended to the base of the thumb. The EPL tendon crossed over the extensor carpi radialis tendons where it exhibited a flattened aspect. In the five patients in the study, a tubular-shaped hypoechoic area was evident at the position of the ruptured EPL tendon on sonograms. At surgery, this area corresponded to fluid, hemorrhage, and scar tissue in the EPL tendon sheath. The assessment of tendon retraction on sonography correlated with findings at surgery. CONCLUSION: Sonography may aid in diagnosing a rupture of the EPL tendon and in the preoperative assessment of gap size and position of the retracted tendon ends. A characteristic tubular hypoechoic area may be seen crossing over the extensor carpi radialis tendons.

MR imaging of the postoperative ankle.

Although MRI of the ankle has become a routine diagnostic method to cope with pathologic conditions of the ankle, the literature on postoperative evaluation of the ankle by imaging is very scarce. In this short course, the basic principles on surgical reconstruction techniques of ankle ligaments and tendons will be reviewed. The value of imaging--with emphasis on MRI--in depicting postoperative complications will be discussed as well.

MR imaging findings of bone marrow changes in patients with cystic fibrosis.

The purpose of this work was to evaluate bone marrow abnormalities in the lower limbs of patients with cystic fibrosis by means of MR imaging. Eight patients with cystic fibrosis ranging in age from 16 to 35 years (average age 25.1 years) were evaluated with MR imaging of the lower extremities. T1 weighted spin echo sequences were obtained in all patients. Pelvis, femora and tibia were imaged in the coronal plane whereas the feet were imaged in the sagittal plane. The studies were independently evaluated by two musculoskeletal radiologists. The images were not mixed with disease-free images, but the readers were completely unaware of clinical data. Distribution of haematopoietic and fatty marrow was graded on a 5-point scale. In five patients, both observers considered marrow distribution as probably or definitely abnormal relative to their age. Although our findings are very preliminary, our investigation suggests that cystic fibrosis may be added to the list of disorders in which bone marrow abnormalities may be observed.

CT doses in children: a multicentre study.

We evaluated examination protocols used for common CT procedures of paediatric patients at different hospitals in Belgium in order to determine whether adjustments related to patient size are made in scanning parameters, and to compare patient doses with proposed reference levels. Three paediatric hospitals and one non-paediatric hospital participated in the study. Weighted CT dose-index (CTDI(w)), dose-length product (DLP) and effective dose (E) were evaluated for three patient ages (1 year, 5 years and 10 years) and three common procedures (brain, thorax and abdomen). CTDI(w) and DLP values higher than the reference levels were found for all types of evaluated examination. E ranged from 0.4 mSv to 2.3 mSv, 1.1 mSv to 6.6 mSv, and 2.3 mSv to 19.9 mSv for brain, thorax and abdomen examinations, respectively. All centres but one adapted their protocols as a function of patient size. However, no common trend in the selection of protocols was observed. Some centres divided the whole range of patient size into only two/three groups by age, while others classified the patients into six groups by weight. It was also observed that some centres used the same mAs for the total range of patient sizes and decreased the pitch factor for small children, which resulted in higher doses. This indicates the importance of careful selection of technical scan parameters. If CT parameters used for paediatric patients are not adjusted on the basis of examination type, age and/or size of the child, then some patients will be exposed to an unnecessarily high radiation dose during CT examinations.

Can bone marrow edema be seen on STIR images of the ankle and foot after 1 week of running?

PURPOSE: To evaluate whether initiation of running in sedentary individuals would lead to bone marrow edema on MR images, within the time span of 1 week. MATERIALS AND METHODS: The feet of 10 healthy volunteers were imaged by MR imaging before and after running during 30 min a day for 1 week. The images were evaluated by consensus of 2 musculoskeletal radiologists who graded the presence of bone marrow edema on a 4-point scale. Edema scores and number of bones involved before and after running were compared statistically. RESULTS: Edema was present on the baseline images in 3 subjects. After running edema showed an increase or was present in 5 subjects. The changes after running were statistically significant. Bones involved were the talus, calcaneus, navicular bone, cuboid bone, and 5th metatarsal. CONCLUSION: Edema patterns can be seen in the feet of asymptomatic individuals. During initiation of running an increase of edema or development of new edema areas can be seen.

Comparison of surface coil and knee coil for evaluation of the patellar cartilage by MR imaging.

PURPOSE: The aim of this work was to compare the knee coil and the surface coil for the visualisation of the patellar cartilage. MATERIALS AND METHODS: In 28 patients (17 women, 11 men) with an average age of 40 years (range 14-76) with knee pain MR was performed. Transverse images were obtained using a fast spin echo proton density weighted sequence on a Philips Gyroscan Intera 1.5 T clinical system. Transverse images were obtained at the level of the patellar cartilage using both the surface and the knee coil. All images were evaluated by consensus of two radiologists. They evaluated a number of quality criteria on a 4-point scale. Criteria for artefacts were also graded on a 4-point scale. RESULTS: For the visualisation of fluid there was no significant difference between the knee coil and the surface coil (P=0.021). For all other criteria regarding image quality and presence of imaging artefacts there was a significant difference between both coils (P<0.001) with the surface coil obtaining the better result. CONCLUSION: The use of the surface coil in the visualisation of the patellar cartilage can be recommended at knee MR.

The use of phantoms or tissue simulating test objects in the evaluation of imaging methods.

We reviewed the 1996 issues of Radiology and American Journal of Roentgenology to appreciate the number of phantom studies published. There were 11 studies involving living animals and 51 other phantom studies. The categories chest, CT and MR, and musculoskeletal contained more than 10% of phantom studies in both journals. Design, advantages and limitations of different types of phantom studies are further addressed. Phantom studies offer several advantages over studies in patients in selected circumstances and have an important role in radiology research.

Imaging of semimembranosus bursitis: MR findings in three patients and anatomical study.

We report on three patients with posteromedial knee pain related to semimembranosus bursitis. The semimembranosus bursa has a typical location and morphology around the central tendon of the semimembranosus muscle. These characteristics are demonstrated in patients and by dissection of the tendon and bursa in an embalmed knee specimen.

Inverted Meckel's diverticulum as a leading point for ileoileal intussusception in an adult: case report.

Intussusception due to an inverted Meckel's diverticulum is considered a rare occurrence. We present a case of a 37-year-old male with anemia and melena due to an inverted Meckel's diverticulum at the base of an ileoileal intussusception. To our knowledge, this is the first case in which small bowel enema, computed tomography, and magnetic resonance imaging showed the pathology.

[Radiological differential diagnosis of focal liver lesions with anatomo-pathological correlations]. / Diagnostic différentiel des lésions focales hépatiques avec corrélations anatomopathologiques.

Starting from the macroscopic, microscopic and circulatory characteristics of focal liver lesions, we aimed at assessing the possibilities and the limits of their radiological differential diagnosis. We compared the normal hepatic parenchyma (in terms of: general morphology, cellularity, necrosis, macro- and micro-circulation) and the lesions, assessed following the radiological features of echoreflectivity, RX density, contrast dynamics and specific contrast uptake. The association of morphologic and dynamic features can sometimes lead to an excellent diagnostic specificity (by example: angioma); in other fields, interesting results are noted, but the limits of every modality require further evaluation. This study applies to the following focal lesions: angioma, focal hyperplasia, adenoma, regeneration nodule, hepatocarcinoma, metastasis.

Patient and staff exposure during endoscopic retrograde cholangiopancreatography.

Despite a number of efforts being put into the radiological protection of both patient and staff during interventional radiological (IR) procedures during recent years, information about radiation exposure during endoscopic retrograde cholangiopancreatography (ERCP) procedures remains scarce. The purpose of this study was to estimate both patient and staff radiation doses during therapeutic ERCP procedures by direct measurement and to compare these results with data from other IR procedures. For 54 patients, effective dose and skin dose were estimated by measuring the dose-area product. For staff, entrance surface doses to the lens of the eye, thyroid and hands were estimated by thermoluminescent dosemeters. A median effective dose of 7.3 mSv and a median entrance surface dose of 271 mGy per procedure were estimated for patients. The gastroenterologist received a median dose of 0.34 mGy to the lens of the eye, 0.30 mGy to the skin at the level of the thyroid and 0.44 mGy to the skin of the hands, per procedure. When comparing the dosimetric quantities presented in this study with data from other IR procedures, it is clear that patient skin doses and doses to staff are high owing to the use of inappropriate X-ray equipment. ERCP requires the same radiation protection practice as all IR procedures. It should be consistently included in future multicentre IR patient and staff dose survey studies at national or international level.

Diffusion-weighted MR imaging of an acute venous stroke: case report.

A patient with a superior sagittal sinus thrombosis had progressively worsening symptoms and signs that resolved after IV heparin therapy. MR imaging revealed abnormalities in diffusion, similar to those seen with acute arterial stroke. Abnormalities shown on a T2-weighted fast spin-echo and fluid-attenuated inversion recovery images resolved completely. The findings in this report contradict those from previous reports that suggest diffusion-weighted imaging with quantitative apparent diffusion coefficients may be used in selecting patients for dural venous sinus thrombolysis.

Posterolateral supporting structures of the knee: findings on anatomic dissection, anatomic slices and MR images.

In this article we study the ligaments and tendons of the posterolateral corner of the knee by anatomic dissection, MR-anatomic correlation, and MR imaging. The posterolateral aspect of two fresh cadaveric knee specimens was dissected. The MR-anatomic correlation was performed in three other specimens. The MR images of 122 patients were reviewed and assessed for the visualization of different posterolateral structures. Anatomic dissection and MR-anatomic correlation demonstrated the lateral collateral, fabellofibular, and arcuate ligaments, as well as the biceps and popliteus tendons. On MR images of patients the lateral collateral ligament was depicted in all cases. The fabellofibular, arcuate, and popliteofibular ligaments were visualized in 33, 25, and 38% of patients, respectively. Magnetic resonance imaging allows a detailed appreciation of the posterolateral corner of the knee.

Severe adverse reactions with contrast agents for magnetic resonance: clinical experience in 30,000 MR examinations.

We report on the frequency, manifestations and reactions to gadolinium contrast media in patients who underwent MR imaging at our institution between 1988 and 1998. During a 10-year period 30,000 patients received an intravenous injection of 0.1 mmol/kg gadoterate meglumine or gadopentetate dimeglumine for an MRI examination. When a reaction occurred a written report was made (the events were categorized into mild, moderate, and severe). In the period of 10 years we obtained three reports of moderate or severe reactions to the administration of gadolinium. This paper discusses the safety issues of intravenous contrast media in MR imaging, focusing on two gadolinium complexes, gadoterate meglumine, gadopentetate dimeglumine.

b matrix errors in echo planar diffusion tensor imaging.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is a recognized tool for early detection of infarction of the human brain. DW-MRI uses the signal loss associated with the random thermal motion of water molecules in the presence of magnetic field gradients to derive parameters that reflect the translational mobility of the water molecules in tissues. If diffusion-weighted images with different values of b matrix are acquired during one individual investigation, it is possible to calculate apparent diffusion coefficient maps that are the elements of the diffusion tensor. The diffusion tensor elements represent the apparent diffusion coefficient of protons of water molecules in each pixel in the corresponding sample. The relation between signal intensity in the diffusion-weighted images, diffusion tensor, and b matrix is derived from the Bloch equations. Our goal is to establish the magnitude of the error made in the calculation of the elements of the diffusion tensor when the imaging gradients are ignored.

MR imaging of the medial collateral ligament bursa: findings in patients and anatomic data derived from cadavers.

OBJECTIVE: The purpose of this work was to define the MR imaging findings of fluid collections confined to the medial collateral ligament (MCL) bursa and to correlate these findings with anatomic features shown in cadaveric specimens. MATERIALS AND METHODS: The anatomic location of the MCL bursa was investigated by MR-anatomic correlation in seven cadaveric knees. The MR imaging studies and clinical charts of six patients with fluid collections confined to the MCL bursa were reviewed. RESULTS: On anatomic sections, the MCL bursa was located between the superficial and deep portions of the MCL. Separate femoral and tibial compartments were seen in most specimens. CONCLUSION: The anatomy of the MCL bursa is shown with MR imaging in cadaveric specimens and patients. Understanding the compartmentlike distribution of fluid in the MCL bursa at MR imaging allows accurate diagnosis and differentiation from other conditions.

MR imaging of meniscal cysts: evaluation of location and extension using a three-layer approach.

PURPOSE: To analyze the extension of medial and lateral meniscal cysts relative to the capuloligamentous planes of the knee. MATERIALS AND METHODS: The MR images of 32 patients with meniscal cysts were reviewed. The location and extension of the meniscal cysts with reference to the capsule and ligaments were recorded. RESULTS: Most medial meniscal cysts were located posteromedially. Posteromedial meniscal cysts usually penetrated the capsule and were located between layer I and the fused layers II+III. From this site some extended anteriorly and then became located superficial to the superficial MCL. The location of lateral meniscal cysts was more varied. Anteriorly the cysts were located deep to the iliotibial band, whereas posterolateral cysts were located deep to the lateral collateral ligament. CONCLUSION: Although the site of capsular penetration of meniscal cysts is determined by the location of meniscal tears, the possible pathways of extension appear to be determined by the capsuloligamentous planes of the knee.

Echo planar magnetic resonance imaging of anisotropic diffusion in asparagus stems.

MR diffusion-weighted imaging (DWI) uses the signal loss associated with the random thermal motion of water molecules in the presence of magnetic field gradients to derive a number of parameters that reflect the translational mobility of the water molecules in tissues. In highly organized but asymmetric structures, this mobility may be affected by the obstacles present and this in a direction-dependent way. Important examples of this are white brain matter and the stem of certain plants, both containing fibrous components where diffusion of water molecules across fibers is much more restricted than along the fibers. Diffusion that exhibits such directional dependence is said to be anisotropic, and diffusion tensor magnetic resonance imaging allows localized characterization of this behavior. Interpretation of the information obtained in terms of the underlying tissue structure is often hampered by the complexity of factors that can produce the observed behavior. A phantom that exhibits well-defined anisotropic diffusion and yields sufficient signal can help the experimental testing of the relevant methods and models. In this paper, we have used a phantom consisting of asparagus stems as a test object for assessing the value of the acquisition and postprocessing techniques commonly used in the clinic for this kind of investigation. Because of its strongly fibrous and cylindrically symmetric morphology, exhibiting a well-defined sub-classification of cells on the basis of size and shape, asparagus allows a relatively simple interpretation of the results obtained in the diffusion experiments. Our experiments show that the known structural information about the main cell types encountered correlates well with the behavior patterns of the diffusion parameters.