Variable Imaging Appearances Research Articles

Isolated intramedullary neurosarcoidosis of the thoracic spine: case report and review of the literature

Sarcoidosis can involve the central nervous system in approximately 5-15% of cases. Any part of the nervous system can be involved, so presentation can be quite varied. Isolated disease of the spinal cord is even less common and reports are limited to single cases and small series. Although in the setting of systemic disease the diagnosis can be made with skin or lymph node biopsy, isolated disease of the spinal cord presents a diagnostic challenge. We present a case of isolated intramedullary neurosarcoidosis of the distal thoracic spinal cord presenting with posterior column dysfunction. Imaging demonstrated T2 changes in the patient's lower thoracic cord adjacent to disc herniation. Over time, however, his symptoms progressed despite decompression, and the abnormal region began to exhibit focal contrast enhancement. The persistence of symptoms as well as the new enhancement led us to perform a spinal cord biopsy, which demonstrated histopathological findings consistent with sarcoidosis. Further workup failed to reveal any evidence of systemic disease. Intramedullary sarcoidosis without systemic sarcoidosis is extremely rare. With its variable imaging appearance and inconsistent clinical manifestations, it can be difficult to diagnose. It should be considered in the differential diagnosis of a mass-like intramedullary lesion with progressive symptoms. Biopsy with histopathological correlation may be the only definite management option.

The proximal hamstring muscle–tendon–bone unit: A review of the normal anatomy, biomechanics, and pathophysiology

Proximal hamstring injuries occur during eccentric contraction with the hip and the knee on extension; hence they are relatively frequent lesions in specific sports such as water skiing and hurdle jumping. Additionally, the trend toward increasing activity and fitness training in the general population has resulted in similar injuries. Myotendinous strains are more frequent than avulsion injuries. Discrimination between the two types of lesions is relevant for patient management, since the former is treated conservatively and the latter surgically. MRI and Ultrasonography are both well suited techniques for the diagnosis and evaluation of hamstring tendon injuries. Each one has its advantages and disadvantages. The purpose of this article is to provide a comprehensive review of the anatomy and biomechanics of the proximal hamstring muscle–tendon–bone unit and the varied imaging appearances of hamstring injury, which is vital for optimizing patient care. This will enable the musculoskeletal radiologist to contribute accurate and useful information in the treatment of athletes at all levels of participation.

Variable MR imaging appearances of focal nodular hyperplasia in pediatric cancer patients

Focal nodular hyperplasia (FNH) is rare in the general pediatric population but is increasingly found in treated pediatric cancer patients. FNH can be incidentally found on CT and MRI and can be misdiagnosed as liver metastasis in patients with an oncological history. To describe the MR imaging findings of FNH in pediatric cancer patients. Ten children who had been treated for a primary malignancy and who were diagnosed with FNH from 2003 to 2010 were identified from a search for FNH in our pathology and radiology databases. Patients were included if they were treated for a primary malignancy and had undergone MR imaging of the liver including T1-weighted, T2-weighted and dynamic contrast-enhanced T1-weighted sequences. FNH from all patients (n=10) demonstrated typical homogeneous arterial enhancement on MRI. The FNH was often multiple and small (7/10 patients), lacking a central scar, with variable imaging characteristics including signal hyperintensity on both T1- and T2-weighted images (4/10 patients), especially in the setting of hepatic hemosiderosis. FNH has a variable MR appearance in pediatric cancer patients and should be considered in the differential diagnosis of hypervascular liver lesions.

Adrenal Imaging

Adrenal nodules are frequently encountered on current high-resolution imaging, and accurate characterization of such lesions is critical for appropriate patient care. Our article highlights how imaging techniques such as CT densitometry, CT washout characteristics, chemical shift MRI, PET, and PET/CT help characterize most adrenal lesions. We focus on these techniques as well as specifically, because of space constraints, the varied imaging appearances of adrenocortical carcinoma, pheochromocytoma, and lymphoma on these techniques. The imaging characterization of adrenal lesions has continued to advance over the past decade as new technologies have evolved. CT, MRI, PET, and PET/CT are now established clinical techniques capable of differentiating benign from malignant adrenal lesions.

Changing signal intensity of a craniopharyngioma

Craniopharyngiomas can present as suprasellar cystic lesion with varied imaging appearance. In magnetic resonance imaging using T1-weighted sequence, the cyst can show hypointense, isointense or hyper intense signals depending on the cyst content. We report a case where the T1 signal intensity of a craniopharyngioma changed over time. The hypointense lesion had become hyper intense in the follow-up scan after six months. Such change in signal intensity is described with Rathke's cleft cyst but has not been reported with craniopharyngioma. The possible reason for this change in signal intensity is discussed.

Imaging findings of neonatal herpes simplex virus type 2 encephalitis

The CT, MR, and diffusion-weighted initial and follow-up imaging findings in neonatal herpes simplex virus type 2 (HSV-2) encephalitis were assessed. The clinical, laboratory and imaging findings in 12 patients (eight girls and four boys) with proven neonatal HSV-2 encephalitis with follow-up were retrospectively reviewed. Patterns of brain involvement and distribution of lesions were studied and the contribution of diffusion-weighted imaging to the imaging diagnosis of this disease was explored. A total of 24 CT and 22 MRI studies were performed with a mean follow-up time of 38 months. Neonatal HSV-2 encephalitis can be multifocal or limited to only the temporal lobes, brainstem, or cerebellum. The deep gray matter structures were involved in 57% of patients, and hemorrhage was seen in more than half of the patients. CT images were normal or showed mild abnormalities in the early stages of the disease. Conventional MR images may be normal in the early stages of the disease. Lesions were initially seen only by diffusion-weighted imaging in 20% of the patients and this modality showed a substantially more extensive disease distribution in an additional 50% of patients. In 40% of patients, watershed distribution ischemic changes were observed in addition to areas of presumed direct herpetic necrosis. Neonatal HSV-2 encephalitis has a variable imaging appearance. Diffusion-weighted MRI is an important adjunct in the imaging evaluation of this disease. Watershed distribution ischemia in areas remote from the primary herpetic lesions may be seen.

Extrahepatic Abdominal Hydatid Disease Caused by Echinococcus granulosus: Imaging Findings

The classical findings in hydatid disease caused by Echinococcus granulosus with liver or lung involvement are well known. However, diagnosing hydatid disease at unusual locations may be challenging because of variable imaging appearances depending on the host reaction. The purpose of this pictorial essay is to review the sonographic, CT, and MRI features of extrahepatic abdominal hydatid disease including intraperitoneum, retroperitoneum, diaphragma, bone, and soft tissue of the abdomen. Extrahepatic abdominal hydatid lesions have nearly identical imaging features, including the presence of cyst wall calcification, daughter cysts, and membrane detachment. The combinations of radiologic and serologic tests especially in patients living in the endemic areas contribute to the diagnosis. Despite their rarity, being familiar with the spectrum of radiologic findings in these unusual sites is helpful to improve diagnostic accuracy.

Recurrent ovarian granulosa cell tumors: clinical and imaging features

Granulosa cell tumor of the ovary differs from epithelial ovarian tumors in histologic appearance, clinical course and imaging findings. The purpose of this study was to evaluate clinical and imaging features of recurrent ovarian granulosa cell tumors. We performed retrospective evaluation of the medical, surgicopathologic records and CT or MR images of 11 patients with pathologically proven recurrent ovarian granulosa cell tumor. The first recurrence of granulosa cell tumor was diagnosed at between 4 months and 18 years after the initial surgical resection of tumor (mean; 9.7 years). Six patients relapsed after 10 years after initial diagnosis. The recurrent tumors were located in the pelvic cavity alone in three patients, extrapelvic peritoneal cavity alone in two, both pelvic and extrapelvic peritoneal cavity in three, and paraaortic retroperitoneal space in three. The imaging appearances of recurrent masses were variable ranging from solid masses to completely cystic masses. Recurrent granulosa cell tumor is characterized by late tumor recurrence manifested as a relatively small number of discrete peritoneal or retroperitoneal masses with variable imaging appearances from solid to cystic masses.

The spine in Paget’s disease

Paget’s disease (PD) is a chronic metabolically active bone disease, characterized by a disturbance in bone modelling and remodelling due to an increase in osteoblastic and osteoclastic activity. The vertebra is the second most commonly affected site. This article reviews the various spinal pathomechanisms and osseous dynamics involved in producing the varied imaging appearances and their clinical relevance. Advanced imaging of osseous, articular and bone marrow manifestations of PD in all the vertebral components are presented. Pagetic changes often result in clinical symptoms including back pain, spinal stenosis and neural dysfunction. Various pathological complications due to PD involvement result in these clinical symptoms. Recognition of the imaging manifestations of spinal PD and the potential complications that cause the clinical symptoms enables accurate assessment of patients prior to appropriate management.

Hamstring Muscle Complex: An Imaging Review

Increasing activity in the general population and the high demands placed on athletes have resulted in injuries to the hamstring muscle complex (HMC) being commonplace in sports. Imaging of HMC injuries can form a considerable part of a sports medicine practice, with a wide spectrum of such injuries being reflected in their varied imaging appearances. Magnetic resonance (MR) imaging and ultrasonography (US) are the imaging modalities of choice in this setting. Both MR imaging and US provide exquisitely detailed information about the HMC with respect to localization and characterization of injury. Optimization of MR imaging involves the use of a surface coil and high-resolution techniques, allowing the musculoskeletal radiologist not only to diagnose injury and assess severity but also to provide the clinician with useful clues with respect to prognosis. The portability and availability of US make it an attractive modality for the diagnosis of acute hamstring injuries, although its effectiveness is dependent on operator experience. A thorough knowledge of the HMC anatomy and of the spectrum of imaging findings in HMC injury is crucial for providing optimal patient care and will enable the musculoskeletal radiologist to make an accurate and useful contribution to the treatment of athletes at all levels of participation.

Magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy, usually develops in patients with cirrhosis, growing sequentially from low-grade dysplastic nodules to frank malignant HCC. Its recognition is critical because curative treatment and prognosis require early diagnosis. Survival in patients with HCC relates directly to the number, size, and extent of lesions at diagnosis. Imaging of HCC is complicated because the tumor has a varied imaging appearance and frequently coexists with other cirrhotic nodules. Magnetic resonance imaging (MRI), the best available diagnostic technique, offers good contrast resolution and diagnostic sensitivity ranging from 33% to 77%. The main difficulty is not in diagnosing large tumors, but rather small tumors (<2 cm), because of considerable overlap on imaging between benign (regenerative), borderline (dysplastic), and malignant nodules. Increasing degrees of histological malignancy are associated with increasing arterialization and loss of portal blood supply; therefore, recognition of HCC requires dynamic imaging with gadolinium-enhanced T1-weighted sequence. Typically, HCC is a focal lesion with high signal intensity on T2-weighted images, variable signal intensity on T1-weighted images, intense arterial phase enhancement after gadolinium injection, and isointensity or hypointensity at the portal venous phase. The sensitivity of MRI for detecting small lesions is low, and improvement is still needed. Newer contrast agents, higher field strength (3 Tesla) imaging, and perfusion and diffusion MRI techniques possibly will provide greater sensitivity and specificity for detecting small HCCs in the future.

Hepatic Angiomyolipoma Mimicking Hepatocellular Carcinoma

Angiomyolipoma [AML] is a rare benign lipomatous tumour of the liver. It is typically echogenic on ultrasound, hypodense on computed tomography and hyperintense on magnetic resonance imaging. Its varied imaging appearance is due to the different proportion of the three cell types which make up the tumour. This is a case report of a hepatic AML mimicking hepatocellular carcinoma [HCC] with fatty change in a hepatitis B carrier. Diagnostic difficulty and implications on subsequent management are discussed in the context of an endemic region for HCC.

Dermatofibrosarcoma protuberans: MR imaging features.

The objective of our study was to describe the MR imaging features of 10 cases of histologically confirmed dermatofibrosarcoma protuberans. MR imaging is useful in identifying the extent and location of dermatofibrosarcoma protuberans. Although most cases of this tumor are superficial and well defined, we have shown three cases in which the tumor was in a deep location and one case in which the tumor was ill defined in appearance. Knowledge of the variable MR imaging appearances of these tumors may aid in the diagnosis of difficult or atypical cases.

Radiographic and CT Appearances of the Major Fissures

The major fissure is an important anatomic landmark in the interpretation of chest radiographs and computed tomographic (CT) scans. At radiography, the major fissures normally appear as hairlines of soft-tissue density; at conventional CT, they typically appear as lucent, hypovascular bands; and at high-resolution CT, they most often appear as sharp lines. The superolateral major fissure usually manifests as a curving edge at the upper lateral lung field with lateral opacity and medial lucency. The vertical fissure line appears as a fine, linear shadow, commencing in or near the costophrenic angle and coursing upward. The superomedial major fissure manifests as a short, obliquely oriented straight line. Progressive widening of the major fissure inferiorly manifests as a triangular area of increased opacity and represents intrafissural fat. Various inflammatory, granulomatous, neoplastic, and abnormal hemodynamic conditions involving the major fissure can affect its imaging appearance. Oblique orientation of the major fissure may complicate radiographic interpretation. The fissure may be incomplete or absent, complicating identification of various diseases. An incomplete major fissure may lead to disease spread, collateral air drift, or the "incomplete fissure sign," a sign that may, however, also be present in cases of complete fissure. Knowledge of the anatomy and normal variants of the major fissures is essential for recognizing their variable imaging appearances as well as related abnormalities.

Lymphoproliferative disorders: CT findings in immunocompromised children.

The objective was to evaluate the CT imaging appearance, distribution of disease, type of immunocompromised state, and outcome of children with Epstein-Barr virus-induced lymphoproliferative disorders. Medical records and imaging studies (from four tertiary children's medical centers) were reviewed for pathologically proven cases of lymphoproliferative disorders in patients less than 20 years old. Trends between the CT imaging appearance, distribution, and type of immunocompromised state and prognosis were noted and analyzed with Fisher's exact test. Twenty-seven cases were identified (mean age, 7 years 8 months). Eighteen children had undergone solid organ transplantation (heart, n = 9; liver, n = 7; kidney, n = 2), and four had undergone bone marrow transplantation. Five patients had primary immunodeficiencies. The CT appearance of lymphoproliferative disorders varied and included lymphadenopathy, focal mass or masses, and diffuse infiltration and enlargement of organs without focal mass. The distribution of disease included abdomen (n = 17), chest (n = 10), neck (n = 8), and brain (n = 1). In eight of nine heart transplant recipients, the disease predominantly involved the chest and neck, whereas in all seven liver transplant recipients, the disease was isolated to the abdomen (p = .001). The overall mortality rate of 44% was less related to anatomic extent (multiorgan, 46%; localized, 43%) than to type of immune dysfunction (p = .001): bone marrow transplantation (100%), primary immunodeficiency (80%), heart transplantation (55%), liver transplantation (0%), and kidney transplantation (0%). Lymphoproliferative disorders in children had a variable distribution, imaging appearance, and outcome. However, in recipients of solid organ transplants, the disease tended to occur in the anatomic region of the transplant. Mortality rates were more closely related to the type of underlying immune dysfunction than to distribution of disease.

Syndrome of spotty skin pigmentation, myxomas, endocrine overactivity, and schwannomas (Carney complex): breast imaging findings.

To study the imaging appearances of breast lesions in female patients with Carney complex. Seven patients with Carney complex underwent mammography (n = 5), ultrasound (US) (n = 6), or magnetic resonance (MR) imaging (n = 6) in a prospective study. Previous breast images in three patients were reviewed. Mammograms in two additional patients were retrospectively reviewed. Thus, nine patients aged 16-61 were included in this study. Mammograms showed well-defined, iso- or hypodense masses; most were not calcified. Two lesions contained calcifications; both were biopsy-proved ductal adenomas. US demonstrated solid, hypoechoic, well-circumscribed masses in six patients and complex cystic masses (myxoid fibroadenomas) in one patient. MR imaging with a fat-suppressed, fast spin-echo, T2-weighted sequence demonstrated high-signal-intensity lesions (n = 5). Fat-suppressed, spoiled gradient-recalled-echo MR images demonstrated hypointense lesions with variable contrast material enhancement (n = 5). Five of seven patients in the prospective review had multiple breast lesions on at least one study. Mammograms and US scans were negative in three patients each. Chest and breast MR images were negative in only one patient. Female patients with Carney complex often have multiple breast masses with variable imaging appearances that probably represent myxoid fibroadenomas or ductal adenomas. MR imaging showed the most lesions. These lesions all demonstrate benign characteristics and should not prompt multiple biopsies.

Variable imaging appearances of angiomyolipomas of the liver

Angiomyolipomas of the liver are rare benign tumours. We describe the variable imaging appearances of these tumours in three women. The first two patients underwent ultrasound, computed tomography (CT) and angiography, which demonstrated lesions resembling focal nodular hyperplasia and hepatocellular carcinoma, respectively. Both had histologically-proven liver angiomyolipomas surgically resected. The third patient was incidentally found to have typical features of multicomponented liver angiomyolipoma on CT. Variable proportions of fatty tissue in these tumours are the most likely explanation for their different imaging appearances on CT.

Magnetic resonance imaging of central nervous system haemorrhage.

The variable magnetic resonance imaging appearances of central nervous system haemorrhage, both intra- and extra-axial, are described. These will vary with the type of image contrast (T1 or T2 weighting), the nature of the imaging sequence (spin-echo or gradient-echo) and the time from onset of haemorrhage. Magnetic resonance imaging is a useful technique for imaging haemorrhage in the central nervous system as it yields temporal information about haematoma development, and it is the only non-invasive means of imaging intraspinal haemorrhage. It is, however, limited in the imaging of haematomas within 24 h of onset and in subarachnoid haemorrhage where computed tomography is the investigation of choice.

Hepatic Adenoma and Focal Nodular Hyperplasia: A Diagnostic Dilemma

Focal Nodular Hyperplasia (FNH) and Hepatic Adenoma (HA) remain difficult diagnostic problems due to their variable imaging appearances. Five new cases are presented, illustrating this variability, and the current literature is reviewed. Ultrasonography is a sensitive modality for their detection but is otherwise non-specific. On computer tomography, the presence of a scar suggests FNH, whilst haemorrhage suggests HA. However these features are seen in only a small number of cases. Radionuclide (colloid) scanning aids considerably in FNH but a definitive role has not been found in HA. Angiography is helpful, providing anatomical information, sometimes diagnostic (septated blush in FNH, hypovascular areas in HA) and able to discern benign from malignant lesions. Where imaging is not definitively diagnostic, percutaneous biopsy is indicated if FNH is suspected and surgical biopsy if HA is felt likely.