Low Signal Intensity Mass Research Articles

P708 Multimodality imaging of catheter-related right atrial thrombus: a case report

Abstract INTRODUCTION Catheter-related right atrial thrombosis (CRAT) is potentially life-threatening complication of long-term indwelling central venous catheters (CVC), which are used extensively in various patients. Reported incidence of CRAT is variable (2-62%) and probably underestimated due to predominantly asymptomatic course and lack of routine screening. Main pathogenic mechanisms that promote CRAT include mechanical and chemical injury of atrial endocardium by the catheter and infused drugs, stasis of blood and hypercoaguability. Differential diagnosis between thrombus and other intracardiac masses, especially myxoma, is sometimes very difficult and requires multimodality imaging studies. CASE PRESENTATION 62-years old patient after chemotherapy of lymphoma, in remission, with subcutaneous CVC inserted in right subclavian vein, which was used as chemotherapy port several years ago, was sent to emergency department because right atrial mass was found on elective outpatient transthoracic echocardiography (TTE). Urgent computed tomography (CT) was performed and showed well defined, 1.8 x 2.0 cm large, low attenuating mass with some calcifications. Several features were primarily suggestive of myxoma, however differentiation from thrombus was not possible. Patient was admitted to hospital, where transesophageal echocardiography (TEE) confirmed the presence of heterogenous mass attached to right atrial free wall with tumor-like movement. Mobile catheter tip was nearby and touching the mass irregularly. Although in addition to CT also some echocardiographic characteristics were more consistent with myxoma, there was still high clinical suspicion of CRAT due to multiple risk factors for thrombosis. Cardiac magnetic resonance imaging (MRI) using cine sequence was performed for further evaluation and revealed mobile, homogeneously low-signal intensity mass that remained hypointense on contrast-enhanced sequences (first pass perfusion and late gadolinium enhancement), which led to final diagnosis of thrombus. CONCLUSION CRAT should be suspected and anticipated in all, also asymptomatic patients with long-term indwelling CVC (e.g. for chemotherapy, parenteral nutrition, hemodialysis..), majority of whom have additional multiple risk factors for thrombosis. Routine screening for CRAT can provide early diagnosis and treatment and should be considered especially in high-risk patients in order to prevent potentially severe complications. Although echocardiography is the modality of choice for screening, further imaging modalities, e.g. CT and MRI are often required to differentiate thrombus from myxoma or other cardiac masses. Our case demonstrates difficult differential diagnosis of right atrial mass in an asymptomatic patient with a long-term indwelling chemotherapy port, in whom multimodality imaging studies were performed, but only MRI with contrast-enhanced sequences providing superior tissue characterization, could differentiate between CRAT and myxoma. Abstract P708 Figure. Multimodality imaging of atrial thrombus

Multiple hepatic sclerosing hemangiomas: a case report and review of the literature

BackgroundHepatic sclerosing hemangioma, a very rare benign tumor, is characterized by fibrosis and hyalinization occurring in association with degeneration of a hepatic cavernous hemangioma. Such atypical hemangiomas can be diagnosed incorrectly as primary or metastatic malignancies based on imaging characteristics. We present herein a rare case of giant and multiple hepatic sclerosing hemangiomas that are difficult to differentiate from hepatic malignancies and review the relevant literature.Case presentationThe patient was a 48-year-old male who was found to have multiple hepatic tumors and a giant tumor (67 × 53 mm) superior to the inferior vena cave by an abdominal ultrasonography during a routine medical examination. The patient was referred to our hospital for further evaluations and diagnosis of the multiple hepatic tumors. Dynamic CT showed low-density tumors in the delayed phase suggestive of membrane-covered lesions. EOB-MRI demonstrated a mass with low-signal intensity mass on T1-weighted images and areas of high-signal intensity on T2-weighted images and a hypointense mass in the hepatobiliary phase, which showed high intensity on DWI-based ADC map. FDG-PET showed no accumulation of [18F]-FDG. A provisional diagnosis of multiple scirrhous hepatocellular carcinomas was made on the basis of these imaging studies, and caudate lobectomy of the liver and partial hepatectomy of S2 and S6 were performed. Histopathological examination showed that the tumors were composed of various sized irregularly dilated vessels with some blood thrombi, inflammatory cell infiltration, fibrous and hyalinized sclerotic or myxomatous stroma, resulting in a diagnosis of multiple hepatic sclerosing hemangiomas.ConclusionsDifferentiation of multiple sclerosing hemangiomas from other hepatic malignant tumors, such as intrahepatic cholangiocarcinoma, metastatic liver cancer, and scirrhous hepatocellular carcinoma characterized by abundant fibrous stroma, is difficult because the radiological findings are very similar. Inclusion of hepatic sclerosing hemangioma in the differential diagnosis of multiple liver tumors could enable optimal management; this possibility is important to consider before planning invasive therapies.

Pathology Quiz Case 1

A 70-YEAR-OLD MAN PRESENTED WITH A REcurrent right parotid mass. Five months earlier, he had presented at an outside hospital with a 4.3 3.2 2.6-cm level 2 mass in the right side of his neck. Two months after the excision, the mass recurred. Magnetic resonance imaging of the neck showed a 6 5-cm ill-defined mass of low signal intensity in superficial and deep parotid lobes, with infiltration of the surrounding soft tissues (Figure1). A chest radiograph revealed multifocal opacities. Positron emission tomography–computed tomography showed diffusehypermetabolic lymphadenopathy throughout thebody and hypermetabolic activity in the right parotid gland. An excisional biopsy specimen of a level 2 lymph node on the right side demonstrated follicular hyperplasia, increased immunoblasts, germinal centers, and mantle zones, with no evidence of lymphoma. The patient underwent a right total parotidectomy with facial nerve preservation. Pathologic examination demonstrated marked periductal and interlobular sclerosis with prominent collagen bands, lymphoid hyperplasia with germinal centers, numerous small lymphocytes, and plasma cells (Figure 2 and Figure 3). Immunohistochemical analysis revealed markedly increased IgG4 cells (Figure 4), with more than 80 IgG4-positive plasma cells per high-power field and an IgG4-IgG ratio of 10:1.Pathologic examination showed no evidence of lymphoma. Serologic tests demonstrated elevated levels of IgG (2940 mg/dL [reference range, 690-1660 mg/dL]) and IgG4 (1030 mg/dL [reference range, 4-86]) (to convert IgG and IgG4 levels to grams per liter, multiply by 0.01). Prednisone and azathioprine therapy was initiated, and the patient showed rapid improvement of symptoms and resolution of pulmonary opacities on computed tomograms of the chest. The level of IgG4 decreased to 19.4 mg/dL after 1 month and was then successfully maintained within normal limits, with no disease recurrence at the 9-month follow-up visit. What is your diagnosis?

Symptomatic calcification of the anterior cruciate ligament: A case report

We report a rare case of symptomatic calcification of the ACL. A 31-year-old man complained of severe knee pain with restriction of knee motion from 30° to 130° for a week. Plain radiographs and multi-planar CT revealed calcification within the intercondylar notch with no osteoarthritic changes. MRI revealed a low signal intensity mass near the intact ACL. The ACL appeared bulged by arthroscopy and white and creamy fluid exuded from the partially excised synovial membrane. Pain subsided immediately postoperatively. Histologically, the calcific deposit near the ACL showed negligible degenerative changes and resembled calcifying tendinitis of the rotator cuff. Although calcific deposits rarely affect the knee joint, calcification of the ACL should be included in differential diagnoses for acute knee pain and restricted range of motion such as mechanical locking. This case illustrates that arthroscopic removal of the deposits can be effective.

Dissection Aneurysm of the Radiculomedullary Branch of the Artery of Adamkiewicz With Subarachnoid Hemorrhage -Case Report-

A 60-year-old female presented with sudden onset of severe headache and back pain, followed by nausea. The initial head computed tomography (CT) scan revealed posterior fossa subarachnoid hemorrhage (SAH). Spinal T(2)-weighted magnetic resonance imaging demonstrated SAH, and a homogeneous and slightly low signal intensity mass at T11. Spinal angiography in the early arterial phase revealed a small pearl and string-like aneurysm of the proximal radiculomedullary artery on the left side at the T12 level. Forty days after the onset of SAH, CT angiography demonstrated complete occlusion of the dissecting aneurysm and the preserved anterior spinal artery. The present case of ruptured dissecting aneurysm of the radiculomedullary branch of the artery of Adamkiewicz with SAH underwent subsequent spontaneous occlusion, indicating that the wait-and-see strategy may be justified and will provide adequate treatment.

Obstructive jaundice in an elderly female

A 55-year-old woman presented with 1 month history of right hypochondrium pain, vomiting, and jaundice. On examination, she had tender right hypochondrium and palpable gall bladder. Blood investigations revealed increased white cell count with eosinophilia; serum bilirubin (6 mg/dL) and alkaline phosphatase (900U/L) were raised; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were not significantly elevated. Ultrasonography showed a cyst in the right lobe of liver and dilated common bile duct (CBD) filled with echogenic debris. Gall bladder was distended and transonic. MRCP was performed for further evaluation. Cholangiographic thick slab MRCP revealed a cyst in the right lobe of liver closely related to right lobe ducts, with intracystic linear and irregular hypointensities; intrahepatic bile ducts were dilated and CBD filled with long, low signal intensity mass like structure. GB was distended and pancreatic duct slightly dilated [Figure 1]. Figure 1 Thick slab coronal plane MRCP image showing dilated intrahepatic bile ducts and a cyst closely related to right lobe ducts with equivocal evidence of communication. Cyst shows internal low signal intensity membranes; common bile duct is filled with long, ...

Giant malignant ovarian fibrothecoma involved with retroperitoneal structures mimicking a retroperitoneal sarcoma

Ovary is located inside peritoneal cavity. However, a huge malignant ovarian tumor may get involved with retroperitoneal structures. We reported a case of a 70-year-old woman presented with a 2-month history of increased abdominal distention and was subsequently found to have a giant abdominal mass. A huge low signal intensity mass with the involvement of retroperitoneal structures was showed on MRI. At operation, we found that the tumor pushed mesentery and small bowel upwards with the encasement of 10 cm jejunum and was fixed posteriorly to vena cava, aorta, right iliac vessels, and right ureter. It was dissected from the retroperitoneal structures and resected en bloc with the involved jejunum. Although ovary is located inside peritoneal cavity, a huge malignant ovarian tumor may get involved with retroperitoneal structures. So, great care should be taken not to injury the retroperitoneal structures as vena cava, mesenteric vessels, iliac vessels, and ureters.

Diffuse mineralization of forearm extraskeletal chondroma

We report on the clinical, histologic, and radiologic features – including CT and MRI – of extraskeletal chondroma in a rare case of diffuse calcification of the chondroid matrix. T2-weighted MR imaging showed a well-demarcated mass of low signal intensity in the left flexor digitalis profundus, with a slight surrounding intramuscular edema. Histopathological examination revealed a heavily calcified soft-tissue chondroma generating macrophagic foreign body reaction. Knowledge of this unusual pattern of mineralization may help in the radiological diagnosis of extraskeletal chondroma.

Right atrial free-floating thrombus in a patient with massive pulmonary embolism: A case of ‘emboli in transit’

A 78-year-old man was admitted with sudden onset of dyspnea followed by syncope. Contrast-enhanced computed tomography showed embolism in the right main pulmonary artery and left upper pulmonary artery. Echocardiography revealed a large, free-floating thrombus and cine magnetic resonance imaging showed highly mobile, low-signal intensity mass in the right atrium, which protruded into the right ventricle during diastole. During surgery the thrombus migrated into the pulmonary artery trunk, but it was successfully removed.

MRI appearance of primary giant ovarian leiomyoma in a hysterectomised woman

Primary leiomyoma is a rare, benign tumour of the ovary. We describe the MRI features of an ovarian leiomyoma identified in a 51-year-old woman after hysterectomy. The tumour appeared as a well-circumscribed low signal intensity mass on T(1) weighted imaging, with mixed signal intensity on T2 weighted imaging. Areas of high signal intensity on T2 weighted imaging corresponded to degeneration of leiomyoma. Dynamic contrast-enhanced imaging revealed early enhancement of the lesion. MRI appearance was thus similar to that of uterine leiomyoma. This case suggests the potential usefulness of dynamic contrast-enhanced MRI for the diagnosis of ovarian leiomyoma.

Elastofibroma Dorsi as Differential Diagnosis in Tumors of the Thoracic Wall

We report the case of a 73-year-old woman who presented with a soft tissue tumor located between the scapula and the rib cage. Magnetic resonance imaging showed an inhomogeneous tumor on the right dorsolateral thoracic wall that measured 7 x 4 x 7 cm with contrast enhancement. The findings were suggestive of partial infiltration of intercostal muscles and were suspicious of a malignant tumor. After local excision at a district hospital had failed to render definitive diagnosis, the patient underwent complete resection of the tumor at our institution. Histology from the specimen was consistent with elastofibroma dorsi with free resection margins.

Testicular epidermoid cyst in Klinefelter's syndrome

A 38-year-old Japanese man was referred to our outpatient clinic for treatment of infertility. Semen analysis showed azoospermia. Chromosome analysis revealed a 47XXY karyotype, and non-mosaic Klinefelter's syndrome (KFS) was diagnosed. Upon physical examination, the patient's right testicular volume was 30 mL and the left testicular volume was 3 mL. Laboratory tests showed normal levels of lactate dehydrogenase, alpha-fetoprotein, and human chorionic gonadotropin beta-subunit. The plasma luteinizing hormone and follicle-stimulating hormone levels were increased to 15.7 mIU/mL and 45.9 mIU/mL, respectively. The plasma testosterone was decreased to 0.25 ng/mL. Magnetic resonance imaging showed a right testicular mass of low-signal intensity on the T1-weighted image and of high-signal intensity on the T2-weighted image. Therefore, the final diagnosis was KFS with a right testicular tumor. Thus, a right high orchiectomy was performed. Histological examination revealed an epidermoid cyst of the right testis. Epidermoid cysts in cases of KFS are rare. To our knowledge, only seven cases, including ours, have been reported in the literature.

Endometriosis of the vastus lateralis muscle

We report an unusual case of a woman who sought medical attention for a painful mass within her anterolateral left thigh. The patient's symptoms waxed and waned with her menses. Magnetic resonance imaging revealed a 3 cm mass isointense to muscle and surrounded by a rim of decreased signal intensity on T1-weighted images. T2-weighted images with fat saturation revealed a low signal intensity mass with a surrounding rind of high signal intensity edema. Based on its magnetic resonance imaging characteristics, the lesion was initially thought to represent the sequela of prior trauma or perhaps a small fibrous tumor. An excisional biopsy of the mass, however, revealed endometrial tissue, and a pathologic diagnosis of intramuscular endometriosis was rendered.

Microcystic meningiomas: radiological characteristics of 16 cases

As a rare subtype of meningioma, only a few reports deal with radiological characteristics of microcystic meningiomas and the problem remains controversial. The authors have analyzed the radiological findings of a series of microcystic meningiomas with a special focus on magnetic resonance images (MRI) and conventional angiography. Sixteen patients of histologically proven microcystic meningiomas were included. Analysis of preoperative MRI including signal intensity characteristics, enhancement patterns and peritumoural edema were performed and correlated with angiographic and histological findings. Peritumoural edema was graded using edema index (EI) which was defined as the ratio of VE/VT. The tumours were uniformly visualized as a high-signal mass lesion in T2-weighted images and as a low-signal mass lesion in T1-weighted images regardless of tumour vascularity shown by angiography. T2-weighted images revealed that peritumoural brain edema was severe in 11, moderate in 1, mild in 2 and negligible in 2 patients and this was closely related to the co-existence of irregular tumour marginal enhancement. However, other features failed to distinguish these lesions from other subtypes of meningioma. The cases presented demonstrate that characteristic MRI findings suggestive of microcystic meningiomas are; (1) low signal intensity mass in T1- and high signal intensity mass in T2-weighted images; (2) high incidence of peritumoural edema.

Knee Pain in a 13-Year-Old Boy

Knee Pain in a 13-Year-Old Boy

Imaging of Spinal Infections in Children

Infections of the spine in children consist of osteomyelitis and the so-called spondyloarthritis or diskitis. The hallmark of radiographic diagnosis is disk space narrowing with destruction of the two adjacent vertebral body surfaces. 3 , 5 , 26 , 29 Localization of infection to the osseous and articular structures of the vertebral column is not as common in children as adults. The most common route of contamination of the spine is by a hematogenous pathway, either by an arterial route or Batson's paravertebral venous system. The arterial pathway can be implicated by the localization of early infection in the subchondral region of the vertebral body, where numerous arterial loops are present. Infection may also be distributed along the course of the ascending and descending nutrient branches of the posterior spinal artery. The direction and extent of flow through the valveless venous plexus are significantly influenced by changes in intra-abdominal pressure, which may account for the contamination of the spine that may be observed in a child with urinary tract and other pelvic infections. 17 Infection of spine may also occur secondary to spread from a contiguous contaminated source or from direct implantation. Subligamentous spread of infection with subsequent bony invasion is more characteristic of tuberculosis than pyogenic infection. Direct implantation of organisms can occur during punctures of the spinal canal. Postoperative infection may develop following laminectomy or other instrumentation such as scoliosis repair. The cervical spine may be infected by direct extension from prevertebral abscesses, especially those associated with sharp foreign bodies in the pharynx. Vertebral and disk infections account for approximately 2% to 4% of all cases of osteomyelitis with equal incidence in boys and girls. The symptoms include fever; malaise; weight loss; back pain, which may be intermittent or constant; or hip contracture, which occurs secondary to psoas muscle irritation. The erythrocyte sedimentation rate is elevated, but serum leukocyte count may be normal and organisms may not be recovered from blood cultures. The most common early focus of hematogenous osteomyelitis of the spine is the anterior subchondral region of the vertebral body adjacent to the intervertebral disk. The diagnosis of infection is suggested by rapid loss of disk height and adjacent lysis of bone (Figs. 1 and 2) . Involvement of two contiguous vertebral bodies almost always represents transdiskal infection rather than multicentric foci. With vertebral osteomyelitis, bone scintigraphy usually shows diffuse uptake of the radiopharmaceutical within the involved vertebra in blood pool and delayed images. A butterfly pattern of uptake on gallium scintigraphy has been described in vertebral osteomyelitis. White blood cell imaging of osteomyelitis of the spine has been disappointing. Most foci of infection demonstrate increased activity, but photopenia has also been reported in osteomyelitis of spine. MR imaging is the modality of choice for early diagnosis of vertebral osteomyelitis. MR imaging is more sensitive in the detection of vertebral osteomyelitis than either conventional radiography or CT scan and nuclear scintigraphic studies. 21 The appearance of vertebral osteomyelitis on MR images has been characterized as (1) confluently decreased signal intensity of the vertebral bodies and associated interspace with poor distinction between these on short TR, short TE images; and (2) abnormal increased signal of the disk on long TR, long TE images with an abnormal configuration (i.e., absent intranuclear cleft); and (3) increased signal of the vertebral end plates at the abnormal disk level on long TR, long TE images. 2 , 22 , 29 In advanced stages of infection, such as tuberculous spondylitis, a soft tissue mass of low signal intensity on T1-weighted images and of high signal intensity on T2-weighted images is frequently observed. Unlike neoplastic disease, infection is associated with loss of disk space height and the low signal intensity in transnuclear cleft normally seen on T2-weighted images. Increased T2 signal within the vertebral body marrow often precedes abnormal uptake on technetium 99m scintigraphy. Gadolinium chelate enhancement further increases sensitivity (Figs. 2 B, 3 B, and 4 A). Soft tissue extension from spinal osteomyelitis in the form of epidural abscess or paravertebral abscess is well demonstrated by MR imaging (see Fig. 4 A) and enhanced CT scan. Following treatment, a radiodense “ivory” vertebra may be seen. The affected disk space may remain relatively intact, or complete bony ankylosis may occur.

A symptomatic cyclops lesion 4 years after anterior cruciate ligament reconstruction

The cyclops lesion is a fibrous nodule with central granulation tissue located anterolateral to the tibial tunnel after intra-articular reconstruction of the anterior cruciate ligament (ACL) that has been shown to be a cause of failure to regain full extension in the early postoperative period. We present the case of a 23-year-old woman who had undergone arthroscopic ACL reconstruction with a patellar tendon autograft 4 years prior to presentation. Following her reconstruction, she regained full range of motion and returned to collegiate cheerleading. At presentation, she complained of a gradual loss of full extension and joint-line pain with terminal extension. On examination, her graft was stable and she lacked 3° of extension. Magnetic resonance imaging documented a 1-cm mass of low signal intensity immediately anterior to the ACL graft within the intercondylar notch. At arthroscopy, a large amount of thick, immobile scar tissue was found immediately anterior to the ACL, consistent with a cyclops lesion. The lesion was debrided and the patient did well postoperatively. Patients who present with delayed-onset loss of extension after ACL reconstruction should undergo careful evaluation including radiographs and magnetic resonance imaging. If a cyclops lesion is diagnosed, arthroscopic resection should be undertaken.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 2 (February), 2001: pp E8–E8

Calcium pyrophosphate dihydrate crystal deposition in and around the atlantoaxial joint: association with type 2 odontoid fractures in nine patients.

To investigate the histopathologic anatomy of calcium pyrophosphate dihydrate (CPPD) crystal deposition in and around the atlantoaxial joint and the association between CPPD crystal deposition and subchondral cysts, erosions, and fracture involving the odontoid process of the axis. One adult cadaver demonstrating calcification in the retro-odontoid area at computed tomography (CT) was selected for further radiography, CT, and magnetic resonance (MR) imaging at the C1-2 level. Anatomic sectioning and histologic evaluations were performed in the specimen. For clinical study, radiographs (n = 5), CT scans (n = 8), and MR images (n = 6) in nine patients (mean age, 74.4 years) with odontoid process fractures and CPPD crystal deposits in and around the atlantoaxial joint were reviewed. In the cadaveric specimen, radiography and CT demonstrated calcifications in the transverse ligament; histologic evaluation confirmed that these calcifications were CPPD crystal deposits. In all nine patients, radiography (n = 5) and CT (n = 8) also showed calcification in areas adjacent to the odontoid process, which included the transverse ligament. T1- and T2-weighted MR imaging showed a retro-odontoid mass of low signal intensity that compressed the cervical cord in six patients. CT, MR imaging, or both demonstrated subchondral cysts, osseous erosions, or a type 2 odontoid fracture in all patients. CPPD crystal deposition disease involving the C1-C2 articulation can be a clinically important entity that may place affected patients at increased risk of pathologic fracture of the odontoid process.

Atrial myxoma demonstrated by cine gradient refocused echo magnetic resonance imaging

A case of atrial myxoma presenting with syncope evaluated by echocardiography and MRI is described. Cine gradient-echo MRI demonstrated atrial myxoma as a very low signal intensity mass indicating the presence of haemosiderin.

Shoulder MRI after surgical treatment of instability

Objective: To analyze magnetic resonance imaging (MRI) findings of the shoulder after an instability operation. Materials and methods: Physical examinations, radiographs and MRI of 10 patients after anterior glenoid bone block insertion for ventral instability were compared. MRI included T 1-weighted spin-echo (TR=600, TE=20 ms) and T 2*-weighted gradient-echo sequences (TE=600, TE=18, Flip=30°) in the axial, oblique-coronal and oblique-sagittal planes. Results: No patient suffered from recurrent subluxation. We found fusion of the bone block with the anterior glenoid in seven cases, dislocation of the bone block without contact to the glenoid in one case, and no visible bone block in two cases. On MRI, the bone block showed either signal intensity equivalent to fatty bone marrow ( n=4) or was devoid of signal consistent with cortical bone or bone sclerosis ( n=4). In all patients, a low signal intensity mass, 2–4 cm in diameter, was visible next to the glenoid insertion site. Conclusion: Insertion of a bone block onto the anterior glenoid induces formation of scar tissue, increasing the stability of the shoulder joint. This scar is well visible on MRI and forms independently of the behavior of the bone block itself. MRI is ideally suited for evaluating postoperative shoulder joints after bone-grafting procedures.