Intravenous Administration Of Gadolinium Research Articles

Echocardiography and cardiovascular magnetic resonance diagnostic role in Takotsubo cardiomyopathy

We presented the case of a diabetic 67-year old female patient suffering from "Takotsubo cardiomyopathy". She arrived at the emergency department with severe chest pain soon after acute emotional and physical stress. The echocardiography performed in the acute phase showed balloon-like left ventricular wall motion abnormality with severe global dysfunction that showed complete normalization 4 days after the onset of symptoms. Cardiovascular magnetic resonance in the acute phase showed a small subendocardial hypo-perfusion area in the inferior wall (no longer present at the 3 week follow-up evaluation) and delayed hyperenhancement after administration of intravenous gadolinium in the same region that showed a significant reduction after 3 weeks.

Time‐resolved dynamic contrast‐enhanced MR urography for the evaluation of ureteral peristalsis: Initial experience

To determine the feasibility of time-resolved dynamic contrast-enhanced magnetic resonance urography (MRU) for the evaluation of ureteral peristalsis using a data-sharing 3D gradient echo sequence with spiral k-space filling. Eight patients (M=3, F=5, mean 48.1 years) were referred for MRU for the evaluation for renal mass (n=3), hematuria (n=2), urinary tract tuberculosis (n=1), postoperative bladder cancer (n=1), and postoperative ureteric reimplantation (n=1). Dynamic MRU was performed for 120 seconds at 1.5T after intravenous furosemide and gadolinium administration using an oblique sagittal, time-resolved T1 3D gradient echo sequence with 1 second effective temporal resolution. Study quality was assessed based on artifacts and extent of ureteric visualization. Frequency of peristalsis from the renal pelvis to urinary bladder was evaluated for each subject. A total of 16 ureters were examined. Image quality was good in four ureters, satisfactory in 11 ureters, and poor in one ureter. Mean peristaltic frequency was 3.5 waves per minute (range, 2.5-6.5 waves/minute) in normal ureters (n=11). Five ureters were considered abnormal (one urinary tract tuberculosis and four postsurgical ureters), and all had decreased or no peristalsis (0-1.5 waves per minute). MRU using a time-resolved, data-sharing 3D contrast-enhanced technique is able to demonstrate ureteral peristalsis and permits quantification of ureteral peristaltic frequency.

Effects of intravenous gadolinium administration and flip angle on the assessment of liver fat signal fraction with opposed‐phase and in‐phase imaging

To assess the effects of intravenous gadolinium (Gd) and flip angle (FA) on liver fat quantification by opposed-phase (OP) and in-phase (IP) imaging. Our Institutional Review Board (IRB) approved this Health Insurance Portability and Accountability Act (HIPAA)-compliant, retrospective, clinical study. We identified 79 patients in whom abdominal OP and IP gradient-echoes were obtained at 1.5T before and after Gd administration. All 79 patients were imaged at high FA (> or =70 degrees ); 57 were also imaged at low FA (< or =20 degrees ). Fat signal fraction (FSF) was calculated from pre- and post-Gd liver images for each subject and FA using the formula, FSF = (S(IP) - S(OP))/2S(IP), where S(IP) and S(OP) are the OP and IP signal intensities, respectively. The dataset pairs (pre-Gd vs. post-Gd; high-FA vs. low-FA) were compared using linear regression analysis. Before Gd, FSF was significantly greater at high FA than at low FA, with regression parameters (slope/intercept) of 1.27*/0.02*, where * indicates P value <0.01. After Gd, FSF was similar at high and low FA (0.99/-0.00). Gd administration caused an FA-dependent reduction in FSF, larger at high FA (0.68*/-0.03*) than at low FA (0.94, -0.01*). FSF by OP-IP imaging is highly dependent on FA before Gd, but this dependency is eliminated after administration of Gd. Gd appears to minimize the effect of T1-weighting and may improve the accuracy of liver fat quantification.

MR Imaging of the Midfoot and Forefoot

AbstractMR imaging is the diagnostic modality of choice for the evaluation of traumatic, inflammatory and neoplastic processes affecting the midfoot and forefoot soft tissue structures including muscles, ligaments, and tendons. MR imaging is also valuable in the diagnosis of occult bony trauma, stress reaction or fractures, and osteomyelitis. Exquisite contrast resolution, noninvasiveness, and multiplanar capabilities are unique features that make MR imaging a powerful diagnostic technique. The authors employ a basic protocol using T1‐weighted, fast spin echo proton density with and without frequency‐selective fat saturation, and fast spin echo T2‐weighted sequences as well as short‐tau inversion recovery (STIR) imaging. Additional imaging following intravenous gadolinium administration is indicated when osteomyelitis and neoplastic processes are suspected. Post‐contrast fat‐suppressed T1‐weighted sequences are necessary if intravenous or intra‐articular gadolinium is utilized.

Lipomatous lesions of the head and neck region: imaging findings in comparison with histological type

Aim of the study is to demonstrate the main role of magnetic resonance imaging in the identification and characterization of lipomatous lesions of the head and neck. CT and MRI findings of 78 patients (43 male, 35 female) aged 12-80 (mean 47.5) years surgically treated for lipomatous lesions of the head and neck region between January 1995 and June 2005 were retrospectively analysed and correlated with the histological results. On CT images, lipomas and fibrolipomas appeared as smooth (38/50 cases) or lobulated (12/50 cases) well-defined masses associated with moderate displacement of surrounding tissues; tumours had high signal intensity on MR T1-weighted images, with relative decreasing signal on T2-weighted images. Infiltrating lipomas appeared as expansile ill-defined masses with heterogeneous signal. Angiolipomas showed a characteristic contrast enhancement on both CT and MRI. In one case of sialolipoma, the lesion appeared markedly heterogeneous in signal. MR and CT images of Madelung's disease showed multiple symmetrical lipomatous masses involving the neck region. Intraosseous fatty lesions appeared as well-defined hypodense masses sometimes associated with cortical expansion and disruption. Both CT and MRI exams are useful for detecting lipomatous lesions. MRI, however, is more accurate in the evaluation of their extent and in the characterisation of uncommon lipomatous lesions of the head and neck, and intravenous administration of gadolinium better depicts the margins of the tumour and its vascularisation.

Un lymphome musculaire : à propos d’une observation

Skeletal muscle involvement is uncommon in lymphoma, occurring in less than 1.5% of patients. We report the original case of a 61-year-old man who presented with pseudotumoral muscle lesions of the lower limbs, revealing non-Hodgkin T-cell lymphoma. In our patient, magnetic resonance imaging (MRI) was useful in clearly revealing the detailed anatomic extent of muscle change; indeed, MRI showed muscle enhancement after intravenous administration of gadolinium on T1-weighted images as well as high-signal intensity on T2-weighted images. Moreover, MRI was helpful in guiding the optimal site for muscle biopsy.

Comparative evaluation of multidetector CT and MR imaging in the differentiation of adnexal masses

The purpose was to compare the accuracy of multidetector CT (MDCT) on a 16-row CT scanner and magnetic resonance (MR) imaging in the characterization of ovarian masses. Preoperative CT examination of the abdomen and MR imaging of the pelvis was performed in 67 women, with clinically or sonographically detected adnexal masses. The CT examinations were performed on a 16-row CT scanner, and the protocol included scanning of the abdomen during the portal phase, using a detector collimation of 16 x 0.75 mm and a pitch of 1.2. We used a 1.5-T magnet unit to perform T1, T2 and fat-suppressed T1-weighted sequences, before and after intravenous administration of gadolinium chelate compounds. The accuracy of multidetector CT and MR imaging in the differentiation between benign and malignant ovarian masses was evaluated, using histopathologic results as the standard of reference. The sensitivity, specificity and accuracy of MDCT in the characterization of ovarian masses were 90.5%, 93.7% and 92.9%, respectively, and that of MR imaging 95.2%, 98.4% and 97.6%, respectively. Although MRI performed slightly better, this did not reach statistical significance. In conclusion, both MDCT on a 16-row CT scanner and MR imaging demonstrated satisfactory results in the characterization of ovarian masses.

Magnetic resonance imaging of eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis following eating freshwater snails

Angiostrongyliasis cantonensis is a worldwide-existing parasitic disease. However, the relevant reports on its radiological appearances are limited. In this study, we investigated magnetic resonance imaging (MRI) features of eosinophilic meningoencephalitis in a group of consecutive patients caused by human infection with Angiostrongylus cantonensis after eating freshwater snails. We performed brain MR imaging on 74 patients with angiostrongyliasis cantonensis. The scanner was a 0.5T unit. For each patient MR pulse sequences of SE T1-weighted image (T1WI) and FSE T2-weighted image (T2WI) were used. After intravenous administration of gadolinium chelate (Gd-DTPA) repeated T1-weighted images were obtained. MRI features of the lesions in the brain and meninges were analyzed and recorded after observing initial and follow-up MR images. The classification of the types of angiostrongyliasis cantonensis infection was done on the basis of locations of the disorders. Forty-one (55%) normal and 33 (45%) abnormal MRI appearances in the brain were found. According to locations of the disorders, the types of angiostrongyliasis cantonensis infection were determined as follows: seventeen cases of type meningitis, three of type myeloencephalitis, one of type neuritis and twelve of mixed type (eight of type ventriculitis and five of type pneumonitis were among them). In type meningitis, abnormal leptomeningeal enhancement was visualized. In type myeloencephalitis, lesions in the brain parenchyma may have iso- or slightly low signal intensity on T1WI and high signal intensity on T2WI. Enhanced nodules in various shapes were shown on gadolinium-enhanced T1WI, a few lesions appeared as crescent enhancements and some lesions did not reveal abnormal enhancement. Other than brain lesions, an enhanced nodule was seen in the cervical spinal cord in one patient. In type ventriculitis, brain ventricular enlargement was demonstrated. In type neuritis, a nodule and abnormal enhancement in the right optic nerve was revealed. In type pneumonitis, patchy ground-glass opacity and consolidative lesions at the periphery of the lungs were seen. Follow-up results indicated that most lesions in the brain could resolve in 2 to 8 weeks. Angiostrongyliasis cantonensis presented as both single type and mixed type. Nodular enhancing lesions in the brain and/or linear enhancement in the leptomeninges were the main findings, while crescent enhancement would be the characteristic sign of the disease on gadolinium-enhanced T1WI. Focal edematous changes without contrast enhancement in the brain could be seen on MRI in some cases.

Individual Kidney Blood Flow Measured with Contrast-enhanced First-Pass Perfusion MR Imaging

The study design was HIPAA-compliant and approved by the Institutional Review Board, with all participants providing signed informed consent prior to the study. The purpose of this study was to prospectively evaluate the feasibility of determining renal blood flow (RBF) by using a technique based on intravenous administration of gadolinium chelate and evaluation of first-pass gadolinium chelate perfusion by using highly accelerated three-dimensional (3D) gradient-echo magnetic resonance (MR) imaging of the kidney in freely breathing subjects. Flow is determined with Kety-Schmidt formalism by modeling the uptake of gadolinium chelate in the kidney prior to its leaving through the venous system. Validation of the gadolinium chelate perfusion technique is based on comparison of values determined for participants with phase-contrast gradient-echo imaging. The model fit to the measured data is excellent over the first 7-8 seconds of gadolinium chelate uptake and diverges after its appearance in the renal vein. The perfusion data analysis technique showed less than 10% interobserver variation. The average difference between phase-contrast and gadolinium chelate perfusion measurements was 0.08 mL/sec (95% confidence interval: -3.73, 3.58) for left and right kidneys. This study demonstrates feasibility of the gadolinium chelate perfusion method for RBF measurement and discusses potential applications. http://radiology.rsnajnls.org/cgi/content/full/246/1/241/DC1.

Abstract 1761: An Uncommon Cause of Stroke in a 41-Year-old Female

A healthy 41-year-old female experienced sudden onset of right hand weakness, right facial droop and garbled speech. The symptoms lasted for several minutes and then resolved spontaneously. Neurologic exam and head CT were unremarkable. Brain magnetic resonance (MR) imaging demonstrated an infarct in the left frontoparietal operculum; head and neck MR angiogram was unremarkable. A trans-thoracic echocardiogram (TTE) was obtained to evaluate for a patent foramen ovale (PFO) as a cause of paradoxical embolus. Although there was no evidence of PFO, the TTE revealed a 7 × 8 mm pedunculated mass attached to the aortic valve. Trans-esophageal echocardiogram (TEE) confirmed the finding of a highly mobile, echo lucent mass most suggestive of a papillary fibroelastoma (PFE). However, valvular vegetation, thrombus and other primary intra-cardiac tumor could not be excluded. A cardiac MR scan was obtained to further characterize the mass. T2-weighted images demonstrated increased signal within the core of the mass, making tumor more likely than infectious vegetation. The mass also more than doubled in signal intensity after intravenous administration of gadolinium confirming the presence of a vascular source and making thrombus unlikely. The results of non-invasive imaging strongly suggested PFE. In the absence of other stroke source, surgical resection was recommended. Histology of the mass demonstrated a typical budding pattern of fibrous and elastic tissue, confirming the diagnosis of PFE. Papillary fibroelastomas are rare, accounting for less than 10% of primary cardiac tumors; however, they are the most common tumor associated with heart valves. Most PFE are asymptomatic and discovered incidentally. However, due to the risk of embolism, surgical resection is recommended for symptomatic or large left-sided tumors. This case illustrates the importance of a broad differential diagnosis when evaluating a common syndrome (ischemic stroke) in an uncommon circumstance (young patient). It also demonstrates the complimentary nature of echocardiography and cardiac MR in confirming the diagnosis of a cardiac mass prior to invasive therapy. As such, multi-modality imaging has become integral in the evaluation and management of cardiovascular disease.

Assessment of inflammatory activity in Crohn’s disease by means of dynamic contrast-enhanced MRI

Our aim was to perform a dynamic study of contrast enhancement of the intestinal wall in patients with Crohn's disease to quantitatively assess local inflammatory activity. We studied a population of 50 patients with histologically proven Crohn's disease. Magnetic resonance imaging (MRI) was performed using a 1.5-T magnet with a phased-array coil and acquisition of T2-weighted single-shot fast spin echo (SSFSE) half Fourier sequences before intravenous administration of gadolinium, and T1-weighted fast spoiled gradient (FSPGR) fat-saturated sequences before and after contrast administration. Before the examination, patents received oral polyethylene glycol (PEG) (1,000 ml for adults; 10 ml/Kg of body weight for children). Regions of interest (ROI) were placed on the normal and diseased intestinal wall to assess signal intensity and rate of increase in contrast enhancement over time. Data were compared with the Crohn's Disease Activity Index (CDAI). The diseased bowel wall showed early and intense uptake of contrast that increases over time until a plateau is reached. In patients in the remission phase after treatment, signal intensity was only slightly higher in diseased bowel loops than in healthy loops. There was a significant correlation between the peak of contrast uptake and CDAI. Dynamic MRI is a good technique for quantifying local inflammatory activity of bowel wall in patients with Crohn's disease.

Fibroma desmoplásico óseo: a propósito de dos casos

Desmoplastic fibroma is a rare bone tumor with benign, locally aggressive, lytic behavior. Histologically, it is very similar to the more common and better known desmoid tumor. It can occur at any site in the skeleton but is most common in the mandible or in the long bones. We present two cases; the tumor was located in the proximal tip of the fibula in one case and in the proximal tip of the femur in the other. We describe the appearance of these lesions on CT and MRI. In both cases, the lesions were lytic, expansive, with a trabeculated appearance and internal septa, and without mineralized osseous matrix. At MRI, one of the tumors was very heterogeneous, with two differentiated areas on T2-weighted sequences: the upper zone was hypointense and the lower zone showed intermediate signal intensity. We also describe the behavior of the tumor after the administration of intravenous Gadolinium: the upper zone showed no significant enhancement and the lower showed significant enhancement in the early phase.

Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings

Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (chi2=14.0; P<0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction.

Técnica e indicaciones de la resonancia magnética artrografía. Extremidad superior (I)

Magnetic resonance (MR) is the most effective imaging technique in the diagnosis of articular pathology. MR arthrography (MRA), with intra-articular injection of diluted gadolinium or physiological saline solution has become more common in recent years. The intra-articular fluid facilitates the detection of articular pathology by delineating the articular structures, separating adjacent anatomic structures, and filling potential spaces that originate in or communicate with the joint. MRA provides additional information about the integrity of the articular structures, especially cartilage, fibrocartilage, and ligaments. MRA has proven especially useful in the shoulder, where most of the studies have been centered. The detection of subtle lesions of the capsule/labrum complex is fundamental for presurgical evaluation. MRA can be used to complement conventional MR imaging in some cases and in others it is the initial technique of choice. Indirect MRA with intravenous gadolinium administration is based on the enhancement of articular fluid caused by diffusion from the synovial space to the articular space. This technique offers better results in articulations with less capacity for distension, such as the wrist, ankle, hand, and foot. This first part of two-part article reviews the current role of MRA in the upper limb. Special emphasis is placed on the shoulder joint, where its usefulness has been most clearly established. The usefulness of this technique in other joints is also described, reviewing the most important anatomic aspects, techniques and applications.

Gadolinium does not blunt the cardiovascular responses at the onset of voluntary static exercise in cats: a predominant role of central command

The cardiovascular adaptation at the onset of voluntary static exercise is controlled by the autonomic nervous system. Two neural mechanisms are responsible for the cardiovascular adaptation: one is central command descending from higher brain centers, and the other is a muscle mechanosensitive reflex from activation of mechanoreceptors in the contracting muscles. To examine which mechanism played a major role in producing the initial cardiovascular adaptation during static exercise, we studied the effect of intravenous administration of gadolinium (55 micromol/kg), a blocker of stretch-activated ion channels, on the increases in heart rate (HR) and mean arterial blood pressure (MAP) at the onset of voluntary static exercise (pressing a bar with a forelimb) in conscious cats. HR increased by 31 +/- 5 beats/min and MAP increased by 15 +/- 1 mmHg at the onset of voluntary static exercise. Gadolinium affected neither the baseline values nor the initial increases of HR and MAP at the onset of exercise, although the peak force applied to the bar tended to decrease to 65% of the control value before gadolinium. Furthermore, we examined the effect of gadolinium on the reflex responses in HR and MAP (18 +/- 7 beats/min and 30 +/- 6 mmHg, respectively) during passive mechanical stretch of a forelimb or hindlimb in anesthetized cats. Gadolinium significantly blunted the passive stretch-induced increases in HR and MAP, suggesting that gadolinium blocks the stretch-activated ion channels and thereby attenuates the reflex cardiovascular responses to passive mechanical stretch of a limb. We conclude that the initial cardiovascular adaptation at the onset of voluntary static exercise is predominantly induced by feedforward control of central command descending from higher brain centers but not by a muscle mechanoreflex.

Central neurocytoma: clinical, pathological, and neuroradiological findings

AIM To evaluate the clinical, pathological and neuroradiological features of intraventricular central neurocytoma in six patients. MATERIALS AND METHODS Six patients were imaged using non-enhanced and contrast-enhanced magnetic resonance imaging (MRI); three of them were also examined using non-enhanced computed tomography (CT). Two radiologists read the images retrospectively. The imaging data were studied with regard to location, size, margin, signal intensity, enhancement characteristics and presence of calcifications. Clinical data (i.e. presenting signs and symptoms, physical findings and medical histories) were collected and histopathological and immunohistochemical studies were performed by two pathologists. RESULTS All lesions were located in the lateral ventricles. Three tumors were confined to the left side, one to the right side and two cases involved both lateral ventricles. The growth of central neurocytoma was of close spatial relation to the septum pellucidum. On MRI, most of the cases showed a heterogeneous hypointensity on T1-weighted images and hyperintensity on T2-weighted images or FLAIR with a well-defined margin. The presence of cystic components, necroses and calcifications caused these internal heterogeneities. After intravenous administration of gadolinium (Gd-DTPA) all tumours showed a heterogeneous enhancement. CT provided additional information by distinguishing intratumoural calcifications in all three evaluated cases. Immunohistochemical analysis showed positive synaptophysin staining in all cases and positive neuron-specific enolase staining in four cases. In three cases a small proportion of the tumour cells could be labelled with antibodies to glial fibrillary acid protein (GFAP). CONCLUSION Central neurocytoma should be considered when the following conditions occur: young patients with lesions in the lateral ventricle, which contain calcifications and show some enhancement. This is especially applicable for tumours involving both lateral ventricles with symmetrical growth around the centre of septum pellucidum or for unilateral ventricular tumors with a wide base attachment to the septum pellucidum.

Central hypothyroidism and hypophysitis during treatment of chronic hepatitis C with pegylated interferon alpha and ribavirin

Thyroid dysfunction is a known complication of interferon treatment in patients with hepatitis C virus (HCV) infection. Other uncommon endocrine complications have been reported during the treatment of viral hepatitis with IFN-alpha, such as hypopituitarism. A 54-year-old female patient with chronic hepatitis C began treatment with pegylated (PEG)-IFN-alpha 2a 180 mug/week plus ribavirin 1,000 mg/day. At week 20 of treatment, her routine laboratory control showed low levels of thyroid-stimulating hormone (TSH) and free serum thyroxine. This was confirmed at week 24, and other laboratory values showed low levels of adrenocorticotrophic hormone (ACTH). A T1-weighted magnetic resonance imaging scan demonstrated high intensity of the anterior pituitary gland and enhancement after intravenous administration of gadolinium. Hypophysitis with hypothalamic-pituitary dysfunction and secondary or central hypothyroidism was diagnosed on the basis of the clinical features, endocrinological assessment, immunological markers and imaging studies. Twenty-four weeks after stopping treatment, HCV RNA was negative by polymerase chain reaction and alanine aminotransferase values were below the upper limits of normal, and ACTH and thyroid values remained within the reference values. This is the first report of central hypothyroidism and hypophysitis during treatment with PEG-IFN-alpha plus ribavirin, and may be included in the potential list of side effects of the combination treatment.

Central neurocytoma: clinical, pathological and neuroradiological findings

To evaluate the clinical, pathological and neuroradiological features of intraventricular central neurocytoma in six patients. Six patients were imaged using non-enhanced and contrast-enhanced magnetic resonance imaging (MRI); three of them were also examined using non-enhanced computed tomography (CT). Two radiologists read the images retrospectively. The imaging data were studied with regard to location, size, margin, signal intensity, enhancement characteristics and presence of calcifications. Clinical data (i.e. presenting signs and symptoms, physical findings and medical histories) were collected and histopathological and immunohistochemical studies were performed by two pathologists. All lesions were located in the lateral ventricles. Three tumors were confined to the left side, one to the right side and two cases involved both lateral ventricles. The growth of central neurocytoma was of close spatial relation to the septum pellucidum. On MRI, most of the cases showed a heterogeneous hypointensity on T1-weighted images and hyperintensity on T2-weighted images or FLAIR with a well-defined margin. The presence of cystic components, necroses and calcifications caused these internal heterogeneities. After intravenous administration of gadolinium (Gd-DTPA) all tumours showed a heterogeneous enhancement. CT provided additional information by distinguishing intratumoural calcifications in all three evaluated cases. Immunohistochemical analysis showed positive synaptophysin staining in all cases and positive neuron-specific enolase staining in four cases. In three cases a small proportion of the tumour cells could be labelled with antibodies to glial fibrillary acid protein (GFAP). Central neurocytoma should be considered when the following conditions occur: young patients with lesions in the lateral ventricle, which contain calcifications and show some enhancement. This is especially applicable for tumours involving both lateral ventricles with symmetrical growth around the centre of septum pellucidum or for unilateral ventricular tumors with a wide base attachment to the septum pellucidum.

Quadriceps fat pad edema: significance on magnetic resonance images of the knee

While clinically reading magnetic resonance (MR) images of the knees we have occasionally noted edema within the suprapatellar fat pad, with mass effect both on the suprapatellar joint recess posteriorly, and on the quadriceps tendon anteriorly. This MR appearance is analogous to Hoffa's disease described in the infrapatellar fat pad. We sought to evaluate the frequency and pattern of this finding and to provide clinical and histological correlation. The suprapatellar (quadriceps) fat pad was evaluated in 770 consecutive MR examinations (on 1.5 T and 0.3 T) in 736 patients (353 females and 383 males, age range 5-86 years, mean 44.3 years). The MR images were retrospectively evaluated by two observers in consensus for the presence of quadriceps fat pad edema with mass effect. In 46 patients who had intravenous administration of gadolinium, the presence of enhancement was also evaluated. Clinical correlation was performed in abnormal cases; in one patient, 1-year follow-up MRI was evaluated and in one patient a percutaneous biopsy as well as 2-year clinical follow-up was performed. Thirty-two (4.2%) knees in 29 patients showed quadriceps fat pad edema and mass effect. In five of these patients imaging of the contralateral knee was also performed and four of these showed symmetric edema. Another five cases had gadolinium-enhanced images with prominent enhancement. Most patients had clinical symptoms of meniscal tears (n=16, 55%) or anterior knee pain (n=8, 27.6%). The remainder had nonspecific pain (n=4, 13.8%) or suspected avascular necrosis (n=1, 3.4%). In the case with 1-year follow-up MRI, improvement was seen. Biopsy in another patient revealed vasculitis with obliteration of the small vessels. Resection of the fat pad in this patient led to complete resolution of the symptoms. Suprapatellar fat pad edema may be analogous to Hoffa's disease, is rare, and may be a cause of anterior knee pain. However, this finding is not infrequent and its precise association with symptoms remains unclear.

Intradural, extramedullary spinal sarcoidosis: report of a rare case and review of the literature

Background Spinal sarcoidosis represents a rare subgroup of neurosarcoidosis. Most spinal sarcoid lesions are intramedullary, and only eight cases of intradural, extramedullary sarcoid lesions have been reported hitherto. We describe the complete entity of intradural, extramedullary spinal sarcoidosis. Methods A 39-year-old woman presented with a 2-year history of slowly progressive numbness and paresthesia of the right medial upper arm followed by brachialgia and cephalgia. Magnetic resonance imaging revealed an intradural extramedullary T1 isointense and T2 hyperintense mass lesion near the right C3 nerve root exit C3, extending into the right neuroforamen. The cervical cord was not severely compressed. The mass lesion showed a high T2 signal. After intravenous administration of gadolinium–diethylenetriaminepentaacetic acid, there was marked enhancement of the process. Results The patient underwent a C2 to C3 laminoplasty and total resection of the intradural extramedullary tumor. The lesion encroached along the right neuroforamen, involving the C3 nerve root, and was grossly adherent to some of the rootlets. Histopathological examination of the specimen showed a noncaseating granulomatosis consistent with sarcoidosis. Postoperative testing did not reveal systemic involvement of sarcoidosis but bilateral hilar and mediastinal lymphadenopathy with normal lung parenchyma. The patient was therefore treated with corticosteroids. During the follow-up period of 16 months, the patient made a satisfactory recovery, though with persistent, distally pronounced sensory disturbance in the C3 or C4 root areas, and returned to work full-time. Conclusion An extramedullary sarcoid lesion is rare. Unlike intramedullary sarcoid lesions, it can be totally removed. Even if systemic sarcoidosis is present, the patient can have an excellent recovery. From a review of the literature, we can hypothesize that intradural extramedullary spinal sarcoidosis may represent a very early stage of spinal sarcoidosis progressing to intramedullary intradural spinal sarcoidosis. The intradural extramedullary spinal sarcoidosis can be subdivided into a peripheral and a central subtype. Positive histological examination is required to establish the diagnosis since other diagnostic tests are unspecific.