Magnetic Resonance Appearance Research Articles

Diffusion-weighted imaging proves watershed infarction in neurotrichinosis

Central nervous system involvement in trichinosis is rare. Computed tomography (CT) findings in neurotrichinosis are well described, but there are only a few reports about magnetic resonance (MR) appearances. Several pathological mechanisms have been suggested to explain neurological complications. Using sequential diffusion-weighted and conventional MR imaging, we were able to demonstrate bilateral watershed infarction due to eosinophilic vasculitis as the underlying cause of CNS involvement.

Longitudinal CT and MR appearances of hemimegalencephaly in a patient with tuberous sclerosis

A 3-day-old baby was referred to our institution with seizures since birth and a presumptive diagnosis of cerebral tumor detected by prenatal ultrasound. Computed tomography (CT) and Magnetic Resonance (MR) imaging performed immediately after birth revealed the presence of an enhancing mass in the left cerebral hemisphere. The possibility of a congenital malignant brain tumor was considered. Although surgery was advised, the parents opted for conservative medical management. The infant was under treatment for seizures with antiepileptic drugs. At 7-month follow-up, there was a noticeable increase in the seizure activity with signs of developmental delay and increased head circumference. Repeat CT and MR imaging showed features of hemimegalencephaly with a calcified mass involving the left hemisphere. The patient was diagnosed to have tuberous sclerosis. This case report illustrates how an enhancing mass (possibly a tuber) over a period of time diminishes in size and becomes calcified in a patient with tuberous sclerosis and associated hemimegalencephaly.

Magnetic Resonance Imaging of Tendon and Ligament Injuries

Magnetic resonance (MR) imaging is the gold-standard imaging modality for diagnosing tendon and ligament pathology. MR is capable of detecting lesions that are not visible with other imaging modalities. Pathologic changes in tendons and ligaments are seen on MR as changes in size, shape, and/or signal intensity of the affected structure. All tendons and ligaments have individual characteristics and variations in normal appearance. This chapter describes the normal MR appearance of the tendons and ligaments of the distal limb, as well as discussing the ways in which damage to individual tendons and ligaments affects how they appear on MR images.

Magnetic resonance imaging in the evaluation of osteochondritis dissecans of the patella

The objective was to evaluate the magnetic resonance (MR) appearance of patellar osteochondritis dissecans (OCD). We retrospectively analyzed MR images of 16 patients (18 cases, mean age 20 years) using OCD of the patella. In 5 cases surgery was carried out, and we compared the surgical findings with the MR imaging findings in these cases. In all 18 cases, OCD was located central-inferiorly on the patella, and the average size was 11 x 11 x 7 mm. Subchondral deformities were present in 16 out of 18 cases (88.9%), subchondral cyst formation in 4 cases (22.2%), reactive bone marrow signal in 8 cases (44.4%), overlying patellar cartilage abnormality in 14 cases (77.8%), loose body in 2 cases (11.1%), patella alta in 8 cases (44.4%), hypoplastic sulcus in 7 cases (38.9%), and synovitis in 4 cases (22.2%). In all 5 cases in which surgery was carried out, the cartilage abnormality classified on the MR images was confirmed, and a loose body was removed at arthroscopy in 2 of the 5 cases. Magnetic resonance imaging of patellar OCD typically shows subchondral deformity and variable abnormalities of the overlying patellar cartilage located central-inferiorly on the patella.

A wide variety of dynamic contrast-enhanced MR appearances of breast cancer: Pathologic correlation study

PurposeThe aim of this study was to elucidate the characteristic magnetic resonance (MR) appearance of breast cancers, as well as, its variations and to investigate the pathology providing different patterns of dynamic-MR appearances. Materials and methodsFifty-two women with cancer underwent mastectomy (52 tumors resected) and had MR imaging at our institution between April 2001 and March 2004. MR images of T1WI, T2WI, dynamic-MRI and contrast-enhanced T1WI were obtained and evaluated. Dynamic-MR images were correlated with pathological findings. ResultsCommon MR appearance of breast cancer was a focal mass either with irregular or spiculated margins with similar signal intensity on T1WI as and similar to higher signal intensity on T2WI compared to the normal mammary gland. On static contrast-enhanced T1WI, apparent enhancement was typically observed. On dynamic MRI, tumor-rim-enhancement on an early phase image and washout enhancement pattern on dynamic images, both characteristic for breast cancer, were observed, however, the prevalence of them was relatively low, which could be explained by the variation of histopathology among breast cancer nodules. ConclusionIn diagnosing breast masses on MRI, as well as the common and characteristic findings of breast cancer, the variations of MR findings and their underlying histopathology should also be considered.

Fetal Magnetic Resonance Imaging

Fetal magnetic resonance imaging (MRI) is emerging as an important complementary clinical tool to ultrasonography for evaluation of fetal anomalies. Fetal MRI has been in clinical use since 1983; but, early magnetic resonance (MR) sequences were of several minutes’ duration, resulting in significant fetal motion artifact. The recent development of ultrafast MRI sequences allows subsecond image acquisition, minimizing the artifact related to fetal motion. Accurate diagnosis of a fetal anomaly by MRI has the potential to improve parental counseling regarding prognosis and treatment options, assist clinicians with fetal and postnatal management decisions, and plan delivery at an appropriate center for treating the diagnosed anomaly. This review discusses MRI safety and techniques; clinical indications for fetal MRI; and the MR appearance of normal anatomy and anomalies involving the fetal neck, chest, and abdomen.

Magnetic resonance–guided, real-time targeted delivery and imaging of magnetocapsules immunoprotecting pancreatic islet cells

In type I diabetes mellitus, islet transplantation provides a moment-to-moment fine regulation of insulin. Success rates vary widely, however, necessitating suitable methods to monitor islet delivery, engraftment and survival. Here magnetic resonance-trackable magnetocapsules have been used simultaneously to immunoprotect pancreatic beta-cells and to monitor, non-invasively in real-time, hepatic delivery and engraftment by magnetic resonance imaging (MRI). Magnetocapsules were detected as single capsules with an altered magnetic resonance appearance on capsule rupture. Magnetocapsules were functional in vivo because mouse beta-cells restored normal glycemia in streptozotocin-induced diabetic mice and human islets induced sustained C-peptide levels in swine. In this large-animal model, magnetocapsules could be precisely targeted for infusion by using magnetic resonance fluoroscopy, whereas MRI facilitated monitoring of liver engraftment over time. These findings are directly applicable to ongoing improvements in islet cell transplantation for human diabetes, particularly because our magnetocapsules comprise clinically applicable materials.

Imaging Features and Decision Making in Retrobulbar Neuroendocrine Tumours in Horses – Case Report and Review of Literature

A 25-year-old Haflinger gelding was evaluated for chronic-progressive unilateral exophthalmos. Ultrasonographic investigation and magnetic resonance (MR) imaging revealed a retrobulbar space-occupying mass to be the cause of eyeball displacement. Ultrasonographic features were not sufficient to specify the type and extension of the lesion. Magnetic resonance scans, however, clearly displayed an infiltrative intracranial growth pattern but sparing of orbital soft tissues. Based on MR appearance, tentative diagnosis of an orbital soft tissue neoplasia was made and subsequently confirmed by histopathological investigation. The latter revealed a poorly differentiated neuroendocrine tumour. Retrospectively, MR changes resembled those seen with neuroendocrine neoplasms of the human skull. Even if histopathology remains to be elucidated by cytological or histological inspection, MR imaging of equine orbital tumours should provide the criteria necessary for evaluating the therapeutic options and associated prognosis.

Nasal NK/T-cell Lymphoma: Computed Tomography and Magnetic Resonance Imaging Findings

Primary nasal natural killer (NK)/T-cell lymphoma is the most common cellular subtype seen in nasal lymphomas. It is rare in the Western population but occurs more frequently in Asia, South America, and Mexico. The purpose of this study was to describe the computed tomography (CT) and magnetic resonance (MR) imaging findings of primary nasal NK/T-cell lymphoma. During the period between January 1990 and June 2006, the CT (n=24) and MR (n=6) images of 24 patients with biopsy-proved nasal NK/T-cell lymphoma were reviewed retrospectively. Both CT and MR images were evaluated for site and extent of disease and for pattern of involvement of adjacent areas. The most common symptoms at presentation were nasal obstruction, nasal discharge, and epistaxis. There was involvement of the unilateral nasal cavity in 16, bilateral nasal cavity including nasal septum in 5 and nasal choana in 3. Sites of extension outside the nasal cavity included tumor extension into paranasal sinuses (n=15), nasopharynx (n=5), nasal labial fold (n=3), oropharynx (n=2), infratemporal fossa (n=2), other subcutaneous soft tissue of the face (n=2) and anterior cranial fossa base (n=1). Bony destruction was demonstrated in 18 cases, involving the sinus bony wall (n=15), nasal turbinate (n=10), lamina papyracea (n=6), orbital floor (n=3), and hard palate (n=2). Regional lymphadenopathy was also detected in 3 patients with nasal NK/T-cell lymphoma. The CT and MR appearances of nasal NK/T-cell lymphoma are nonspecific, and the diagnosis requires histologic confirmation. However, the differential diagnosis of nasal NK/T-cell lymphoma should be included if the images present soft tissue of the nasal cavity with bony erosion or destruction; involvement of the orbital cavity, nasopharynx and infratemporal fossa; and subcutaneous or nasolabial fold soft tissue infiltration, especially in Asian populations.

Benign adenomyoepithelioma of the breast: imaging findings mimicking malignancy and histopathological features

Adenomyoepithelioma of the breast is a rare neoplasm. We present a case of a benign adenomyoepithelioma of the breast in an asymptomatic 60-year-old woman. This report illustrates the mammogram, ultrasound, and magnetic resonance appearances of this unusual lesion, with histopathological correlation.

SAPHO Syndrome: MR Appearance of Vertebral Involvement

To retrospectively evaluate the magnetic resonance (MR) imaging findings of vertebral involvement in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. Ethics committee approval and informed patient consent were not required for this retrospective study. MR images obtained in 12 patients (seven female, five male; mean age, 42 years; range, 16-65 years) with SAPHO syndrome involving the spine were reviewed. One vertebral lesion separated by one or more normal vertebrae was analyzed as a distinct lesion. For each lesion, the number of associated vertebrae with abnormal signal intensity (SI) (ie, single vertebra, two adjacent vertebrae, or more than two adjacent vertebrae) was noted. The following MR imaging findings were evaluated: cortical bone erosion, abnormal vertebral body SI compared with normal vertebral body SI, increased anteroposterior diameter of the vertebral body, soft-tissue involvement, vertebral body height loss of more than 30%, and abnormal SI of the adjacent intervertebral disk compared with the SI of the other disks. Of 24 vertebral lesions found, 17 involved a single vertebra, four involved two adjacent vertebrae, and three involved three or four adjacent vertebrae. Vertebral corner cortical erosion was present in all lesions, and 23 (96%) lesions had anterior vertebral corner involvement. The erosion was confined to a vertebral corner in five (21%) lesions and included the adjacent endplate and/or the anterior cortex of the vertebral body in the remaining 19 (79%) lesions. In four (17%) lesions, involvement of two adjacent vertebral corners on either side of an intervertebral disk mimicked to some extent early disk space infection. An adjacent disk space was narrowed in six (25%) lesions and exhibited abnormal SI in two (8%). Prevertebral tissue thickening was observed in eight (33%) lesions. Erosion of a vertebral body corner is consistently seen on MR images of SAPHO vertebral lesions and may support the diagnosis of SAPHO syndrome in the appropriate clinical context.

Arcuate ligament of the wrist: normal MR appearance and its relationship to palmar midcarpal instability: a cadaveric study

To describe the magnetic resonance (MR) imaging and gross anatomic appearance of the scaphocapitate (SC) ligament and triquetrohamocapitate (THC) ligament, which are the radial and ulnar limbs of the composite arcuate ligament, a critical volar midcarpal stabilizing ligament. T1 spin-echo and 3D gradient-echo MR imaging in the standard, coronal oblique, and axial oblique planes were performed both before and following midcarpal arthrography in seven cadaveric wrists. The seven specimens were then sectioned in selected planes to optimally visualize the SC and THC ligaments. These specimens were analyzed and correlated with their corresponding MR images. The SC and THC ligaments can be visualized in MR images as structures of low signal intensity that form an inverted "V" joining the proximal and distal carpal rows. The entire ligamentous complex is best visualized with coronal and axial oblique MR imaging but can also be seen in standard imaging planes. SC and THC ligaments together form the arcuate ligament of the wrist. Their function is crucial to the normal functioning of the wrist. Palmar midcarpal instability (PMCI) is a resulting condition when abnormalities of these ligaments occur. Dedicated MR imaging in the coronal and axial imaging planes can be performed in patients suspected of having PCMI.

Medial Collateral Ligament Complex of the Ankle: MR Appearance in Asymptomatic Subjects

To prospectively characterize the spin-echo magnetic resonance (MR) imaging appearance of the medial collateral ligament (MCL) complex of the ankle in asymptomatic volunteers. The study was approved by institutional review board. Informed consent was obtained. MR images in 56 asymptomatic subjects (29 women, 27 men; mean age, 40.7 years; range, 23-60 years) were analyzed by two musculoskeletal radiologists. Visibility and signal intensity characteristics were analyzed for deep (anterior and posterior tibiotalar ligaments [TTLs]) and superficial (tibionavicular ligament [TNL], tibiospring ligament [TSL], and tibiocalcaneal ligament [TCL]) components of the MCL complex. Thickness of ligaments was compared between sexes (Mann-Whitney U test). Associations between age and variables of signal intensity characteristics and morphology were evaluated with Kruskal-Wallis test. Anterior and posterior TTLs, TNL, TSL, and TCL were visible in 31 (55%), 56 (100%), 31 (55%), 56 (100%), and 49 (88%) subjects, respectively. On T1-weighted images, anterior and posterior TTLs, TNL, TSL, and TCL were more commonly of intermediate signal intensity than hypointense (77%, 100%, 93%, 50%, and 73% of subjects, respectively); on T2-weighted images, they were commonly hypointense (55%, 52%, 42%, 75%, and 78% of subjects, respectively). On T2-weighted images, posterior TTL had a striated appearance that was significantly associated with age (P = .004) in 89% of subjects: In subjects younger than 45 years, this striated appearance was present. On T1-weighted images, striation was present in 48% of subjects. Striation was uncommon in remaining ligaments. Mean thickness and range were 1.5 mm and 1-4 mm (anterior TTL), 8.2 mm and 6-11 mm (posterior TTL), 1.6 mm and 1-2 mm (TNL), 2.0 mm and 1-4 mm (TSL), and 1.2 mm and 1-3 mm (TCL). TNL (P = .001) and TSL (P = .003) were significantly thicker in men than in women. In asymptomatic volunteers, posterior TTL and TSL were always visible, but anterior TTL and TNL are only seen in approximately half of subjects. Posterior TTL has a typically striated appearance.

Cavernomatosis múltiple cerebral familiar

Intracraneal vascular malformations are congenital lesions due to alterations in the development of arteriocapillary network. Cavernomas are present in 0.4% of people, and represent 5-13% of all cerebrovascular malformations. They are multilobulated clearly delimited lesions that contain blood at different evolution. Cavernomas can be single or multiple, and sporadic or familial. Inheritance pattern in familial cases is autosomal dominant and three involved genes have been described. We made a retrospective review of clinical histories of two patients diagnosed of multiple familial cavernomatosis. First patient's onset was with partial seizures. Magnetic resonance (MR) showed a frontal cavernoma probable responsible of seizures, and other lesions in frontal and parietal lobes. Second patient consulted for psychomotor delay and behaviour disorder. MR showed multiple cavernomas. In the first patient, one lesion was surgically removed. In second patient, the attitude was expectant. In both cases familial study was done and multiple cavernomas were found in both parents. Cavernomas are a type of vascular malformations with specific histological features. Usual clinical characteristics are seizures and parenchymatous bleeding. The appearance of MR has permitted the diagnosis of asymptomatic cavernomas and is currently considered to be the technique of choice for this purpose. In familial cases, multiple lesions are found in 84%, often in association with family history of seizures. Surgical treatment must be considered in patients with symptomatic or progressive lesions that are accessible. All cases must be clinically and MR followed.

High-resolution Constructive Interference in a Steady State Imaging of Cervicothoracic Adhesive Arachnoiditis

To assess the usefulness of constructive interference in a steady state (CISS) sequence for an evaluation of cervicothoracic adhesive arachnoiditis. Seven patients with arachnoiditis underwent magnetic resonance imaging with T1- and T2-weighted fast spin-echo (FSE) and 3-dimensional CISS sequences. Three observers compared T2-weighted FSE and 3-dimensional CISS images with regard to image quality for spinal adhesive arachnoiditis. Magnetic resonance appearances accompanied with cervicothoracic adhesive arachnoiditis on CISS coupled with T2-weighted FSE sequences were also evaluated. The CISS images were superior to T2-weighted FSE images in the demarcation of spinal cord, dura matter, nerve root, and adhesive point. In our 7 cases with cervicothoracic adhesive arachnoiditis, dural thickening in 2 cases, syringomyelia in 6, arachnoidal cysts in 3, findings of presyrinx in 2, intramedullary microcyst in 2, and deformity of the spinal cord were present. A CISS sequence was more desirable for an evaluation of the cervicothoracic adhesive arachnoiditis than T2-weighted FSE images and could provide useful additional information.

MR Imaging of Stable Posterior Cruciate Ligament Grafts in 21 Arthroscopically Proven Cases

ObjectiveTo describe the magnetic resonance (MR) appearance of intact posterior cruciate ligament (PCL) grafts.Materials and MethodsThirty-one postoperative MR examinations were performed in 21 grafts of 20 patients after PCL reconstruction. All 21 grafts were proven to be intact on second-look arthroscopic examination. Two musculoskeletal radiologists retrospectively analyzed the MR findings and reached decisions by consensus. The signal intensity (SI) of the graft on proton density-weighted and T2-weighted images, as well as the shapes, locations, and segments of increased SI were recorded. The graft thickness was also recorded and correlated to elapsed time since reconstructive surgery.ResultsThe SI of the graft was high (15/31, 48%), intermediate (10/31, 32%), or low (6/31, 19%) on proton density-weighted images, and high (9/31, 29%), intermediate (6/31, 19%), or low (16/31, 52%) on T2-weighted images. The graft SI decreased significantly as postoperative time elapsed. The shape of the increased SI within the grafts was band-like (14/25, 56%) or focal (11/25, 44%). The increased SI was located in the proximal (18/25, 72%), middle (21/25, 82%), and distal (12/25, 48%) segments. In the axial plane, the location of increased SI was intrasubstance (19/25, 76%) or peripheral (10/25, 40%). A 'focal' shape of increased SI was found significantly more in Achilles tendon allografts, while a band-like shape was more frequent in autogenous double-loop hamstring tendon grafts. Graft thickness ranged from 5-15 mm. The difference in graft thickness relative to postoperative time was not statistically significant (p = 0.79).ConclusionStable PCL grafts commonly showed an increased SI at any segment or location, even though they were stable. The shape of increased SI differed according to allograft donor sites. However, SI tended to decrease as time elapsed.

Magnetic resonance imaging assessment of brain maturation in preterm neonates with punctate white matter lesions

Early white matter (WM) injury affects brain maturation in preterm infants as revealed by diffusion tensor imaging and volumetric magnetic resonance (MR) imaging at term postmenstrual age (PMA). The aim of the study was to assess quantitatively brain maturation in preterm infants with and without milder forms of WM damage (punctate WM lesions, PWML) using conventional MRI. Brain development was quantitatively assessed using a previously validated scoring system (total maturation score, TMS) which utilizes four parameters (progressive myelination and cortical infolding, progressive involution of glial cell migration bands and germinal matrix tissue). PWML were defined as foci of increased signal on T1-weighted images and decreased signal on T2-weighted images with no evidence of cystic degeneration. A group of 22 preterm infants with PWML at term PMA (PWML group) were compared with 22 matched controls with a normal MR appearance. The two groups were comparable concerning gestational age, birth weight and PMA. TMS was significantly lower in the PWML group than in the control group (mean TMS 12.44 +/- 2.31 vs 14.00 +/- 1.44; P = 0.011). Myelination (mean 2.76 +/- 0.42 PWML group vs 3.32 +/- 0.55 control group, P = 0.003) and cortical folding (3.64 +/- 0.79 vs 4.09 +/- 0.43, P = 0.027) appeared to be significantly delayed in babies with PWML. Conventional MRI appears able to quantify morphological changes in brain maturation of preterm babies with PWML; delayed myelination and reduced cortical infolding seem to be the most significant aspects.

Multiple intramedullary lipomas with conal intramedullary dermoid: magnetic resonance appearances

Background context Intramedullary fat-containing benign childhood tumors of the cord include lipomas, dermoid cysts, and teratomas. These are embryonal tumors. Most intramedullary fat-containing tumors are solitary. Multiple intramedullary lipomas are rare and may represent a spinal lipomatous malformation. The presence of another intramedullary dermoid tumor in the same case is rare. Purpose The intent of this case report is to look at magnetic resonance features and possible mechanisms of association of these fat-containing intramedullary tumors. Study design/setting A 3-year-old male child presented with spastic quadriplegia. Methods Magnetic resonance imaging (MRI) of spine was done on a 1.5-T scanner in different planes. Results MRI showed multiple intramedullary spinal lipomas with an intramedullary dermoid involving the conus, cord atrophy, and subarachnoid fat droplets. Conclusion Multiple intramedullary lipomas with an intramedullary dermoid represent a form of spinal lipomatous malformation. Both may represent embryogenic mesenchymal inclusions and hamartomatous growth, which can be accurately diagnosed with MRI.

Unusual MR presentation of occult spinal dysraphism with lumbosacral lipoma and dermoid cyst

We describe a case with tethered cord syndrome due to the association of intradural lipoma and a dermoid cyst at the filum terminale that had an unusual magnetic resonance (MR) appearance. Although both pathologies usually demonstrate a similar intensity on MR images, the involvement of a capsule filled with hair in the dermoid cyst, which presented hypointensity, may be a clue to be differentiated from lipoma on preoperative MR images.

Magnetic resonance findings of bile duct adenoma with calcification

Computed tomographic (CT) and magnetic resonance (MR) appearances of bile duct adenoma (BDA in a patient who underwent partial hepatectomy of segment 8 are presented. BDA showed a ring-shaped hyperdense area suggesting calcification and ring enhancement on CT. It appeared hypointense on both T1- and T2-weighted MR images. Preoperatively, the diagnoses considered included metastatic carcinoma, cholangiocarcinoma, tuberculosis, and rare tumors such as epithelioid hemangioendothelioma. The radiological findings were confirmed by pathological investigation.