CT and MR imaging of primary cardiac malignancies.

Primary cardiac malignancies are rare tumors that are difficult to diagnose clinically. Different primary cardiac malignancies may have different clinical, morphologic, and radiologic features and intracardiac locations. Angiosarcoma is the most common primary cardiac malignancy. It tends to occur in the right atrium and involve the pericardium. Because of its tendency to hemorrhage, angiosarcoma often demonstrates areas of increased signal intensity with T1-weighted sequences. Undifferentiated sarcomas typically occur in the left atrium and have variable epidemiologic and radiologic features. Rhabdomyosarcoma is the most common primary cardiac malignancy in children and is more likely than other primary cardiac sarcomas to involve the valves. Primary cardiac osteogenic sarcoma almost always occurs in the left atrium and frequently demonstrates calcification. Certain features (eg, broad base of attachment, origin at a site other than the atrial septum) help differentiate this tumor from left atrial myxoma. Leiomyosarcoma favors the left atrium and tends to invade the pulmonary veins and mitral valve. Fibrosarcoma also tends to occur in the left atrium and is often necrotic. Liposarcoma is very rare and usually manifests as a large, infiltrating mass. Foci of macroscopic fat are occasionally seen. Primary cardiac lymphoma occurs more commonly in immunocompromised patients, frequently involves the pericardium, and, unlike other primary cardiac malignancies, may respond to chemotherapy. The advent of cross-sectional imaging has allowed earlier detection of primary cardiac malignancies as well as more accurate diagnosis and characterization.     

前列腺原发神经内分泌癌的CT、MR诊断

目的探讨前列腺原发神经内分泌癌CT、MR表现特点。方法回顾性分析经手术病理证实的前列腺神经内分泌癌病例5例,年龄68～78岁。临床症状主要是排尿不畅、尿频、血尿。结果本组前列腺神经内分泌癌瘤灶均呈不规则形,体积较大,无钙化灶,增强后不均匀强化。MRI表现为T1WI等信号,T2WI混杂高信号,DWI稍高信号,ADC值约为(0.8～1.0)×10-3 mm2/s,增强后不均匀强化。5例中2例侵犯膀胱,1例侵犯直肠,骨转移4例,肾上腺转移1例,肺部转移3例,肝转移3例,盆腔、髂窝淋巴结转移3例。免疫组化NSE、Cga、Syn检查有阳性表达。结论前列腺神经内分泌癌CT、MR表现为瘤灶较大,形态不规则,常侵犯邻近组织,常伴有远处转移(特别是骨外转移),PSA水平升高不显著。NSE、Cga、Syn的阳性表达对本病的确诊有决定性意义。     

Congenital cholesteatoma of the temporal bone: MR findings and comparison with CT.

PURPOSETo describe the MR findings of temporal bone congenital cholesteatoma and MR usefulness in preoperative diagnosis and follow-up, in comparison with CT.METHODSSeven patients underwent CT and MR studies for facial palsy (n = 3), deafness (n = 3), vertigo (n = 1), tinnitus (n = 1), and otalgia (n = 1). Three patients had for congenital cholesteatoma previously undergone surgery. One of them was free of symptoms and referred for follow-up. Final diagnosis was obtained from surgical data in all the cases but one.RESULTSCongenital cholesteatoma signal intensity was low or intermediate on T1-weighted images and high on T2-weighted images in all the cases. MR was useful in diagnosis in six cases, helping to differentiate congenital cholesteatoma from other nonenhancing tumors. When temporal bone wall erosion was observed with CT (n = 6), MR ruled out intracranial extension in five cases; in one case, MR found an associated epidermoid cyst of the cerebellopontine angle not identified with CT. However, CT assessed relationships with labyrinthine structures more easily.CONCLUSIONMR and CT are complementary in initial diagnosis and follow-up.     

原发性与继发性动脉瘤样骨囊肿CT表现

目的评价CT对诊断与鉴别原发性与继发性动脉瘤样骨囊肿的价值。方法回顾性分析9例经手术病理证实原发性与继发性动脉瘤样骨囊肿的CT征象,并进行献复习。结果9例患中骨皮质缺损征象出现率(67％)高于“液一液平面”出现率(44％)。继发性动脉瘤样骨囊肿骨嵴明显粗大,可构成分房。9例病灶内呈不均匀软组织密度,增强后强化明显。结论CT检查有助于动脉瘤样骨囊肿早期定性诊断,并有助于鉴别原发性与继发性病灶。     

Epidermoidomas of the cerebellopontine angle and temporal bone: CT and MR aspects

Epidermoidomas were found in four locations within and adjacent to the temporal bone: cerebellopontine angle, petrous apex, facial geniculate ganglion region, and tympanic-mastoid cavity. Lesions in each of these locations presented different clinical and imaging characteristics. Cerebellopontine angle epidermoidomas were seen on computed tomography (CT) as low-attenuation masses in the posterior fossa. Petrous apex and geniculate ganglion region lesions destroyed and expanded the bone of their respective regions. Tympanic-mastoid cavity epidermoidomas were relatively nonspecific, soft-tissue masses. CT study of the brain and temporal bone was the single most informative imaging procedure in the preoperative evaluation of these lesions. Magnetic resonance images complemented CT scans for evaluation of the size and extent of the abnormality but were relatively nonspecific and did not allow preoperative differentiation of epidermoidomas from other temporal bone lesions.     

Aneurysmal bone cyst of the temporal bone: MR findings.

MR findings in a case of aneurysmal bone cyst of the temporal bone are described. MR can suggest the diagnosis of aneurysmal bone cyst and also give ancillary information that is helpful for surgical treatment.     

MR of benign chondroblastoma of the temporal bone.

A benign chondroblastoma of the temporal bone in an 8-year-old boy is reported. Head CT showed an expansile mass with calcifications in the center. The tumor appeared as a well-lobulated, hypointense intraosseous mass on T1-weighted brain MR; it was isointense to brain parenchyma on intermediate-weighted images and enhanced homogenously with gadolinium.     

High-grade malignancies of the parotid gland: identification with MR imaging

Most tumors in the parotid gland are either benign neoplasms or low-grade malignancies. The magnetic resonance (MR) images of 29 patients with such tumors were reviewed. These masses typically have low T1-weighted and high T2-weighted signal intensities and have clearly defined margins. The signal characteristics presumably reflect the serous and mucinous products that are characteristic of these lesions. The MR images of six patients with aggressive parotid tumors were reviewed and correlated with operative and pathologic findings. These high-grade parotid lesions are uncommon, usually have poorly defined margins, and have low T1- and T2-weighted signal intensities. These signal characteristics presumably reflect the lack of serous and mucinous products, the high mitotic ratio, and the high nuclear to cytoplasmic ratios that are characteristic of these lesions. The authors conclude that the findings of these tumors on MR images are characteristic and should be suggestive of their diagnosis. The preoperative diagnosis of these high-grade tumors allows a more radical surgical treatment to be well planned before surgery. The primary differential diagnoses of these aggressive tumors with MR imaging include fibrosis and sialolithiasis.     

Barotrauma presenting as temporal lobe injury secondary to temporal bone rupture

We present the case of a scuba diver who experienced acute ear pain during ascent from a dive. CT imaging was performed because of severe unrelenting headache. Blood and gas was identified within the epidural space of the middle fossa and over the petrous bone, as well as hemorrhage within the adjacent temporal lobe. To the best of our knowledge, this is the first case of CT-documented barotrauma affecting the brain as a result of middle-ear gas rupturing through the tegmen tympani.     

CT and MR appearances of parotid pseudotumors in Sj?gren syndrome.

The radiologic findings in eight patients with parotid pseudotumors associated with Sj?gren syndrome (CT in eight; MRI in two) were retrospectively analyzed and compared with the findings in three cases with malignant lymphomas. Diagnosis of pseudotumor was obtained by surgery in six cases and by fine-needle aspiration biopsy and radiologic follow-up in the remaining cases. Six cases (75%) had advanced disease and the remaining had early disease. Both solid (75%) and cystic (38%) masses were seen in the patients with pseudotumors. The masses were solitary in 25%, multiple in 75%, unilateral in 25%, and bilateral in 75%. All three lymphomas were solid masses. The lymphomatous masses were not reliably distinguished from the solid pseudotumors.     

Hemangiopericytoma of the parotid gland: CT and MR features

Hemangiopericytomas are uncommon vascular neoplasms with rare occurrence in the head and neck region. They originate from the pericytes, which are small, oval cells encircling capillaries. Hemangiopericytomas traditionally appear in the retroperitoneum and in the capillaries of the extremities. A case of hemangiopericytoma of the parotid gland is presented. The clinical, surgical, histologic, and radiologic features are described and discussed. Received: 7 February 2000 Revised: 3 March 2000 Accepted: 4 April 2000     

Kimura disease involving parotid gland and cervical nodes: CT and MR findings.

Kimura disease is a rare disease that occurs in Orientals. The majority of lesions occur in the head and neck and most patients have involvement of regional lymph nodes and the major salivary glands. We present a patient with parotid gland and submandibular lymph node involvement. On post-contrast CT the parotid gland enhanced intensely and the enlarged lymph nodes either enhanced diffusely or had rim enhancement. On MR the nodes had high T1-weighted and T2-weighted signal intensities as did portions of the parotid mass. There were suspected flow voids in the parotid mass. The clinical, pathological, and imaging findings are reviewed.     

Ossifying parotid carcinoma ex pleomorphic adenoma: CT findings.

The CT appearance of a large necrotic carcinoma ex pleomorphic adenoma of the parotid gland is described. The tumour contained trabecular bone, which was correctly identified on a preoperative CT examination and which indicated the origin of the tumour to be a benign pleomorphic adenoma. This degree of macroscopic bone formation is rare in pleomorphic adenoma, and its demonstration by CT has not been previously reported.     

Benign and malignant parotid pleomorphic adenomas: CT and MR studies

Parotid pleomorphic adenomas are usually benign, solitary, ovoid masses. Occasionally, these tumors may be highly lobulated and clinically mimic multiple lesions. Actual multiple benign mixed tumors are rare as are malignancies that occur in these pleomorphic adenomas. Of these malignancies, the most common type is the carcinoma ex pleomorphic adenoma. Two patients are presented, one of whom had a markedly lobulated benign mixed tumor and the other patient had an ex pleomorphic malignancy associated with multiple benign mixed tumors. Both cases are documented with CT and magnetic resonance studies. The relative merits of these modalities are discussed as they apply to these parotid masses.     

High-resolution CT of temporal bone trauma

Computed tomographic (CT) findings in 18 patients with temporal bone trauma were reviewed. Eight patients suffered longitudinal fractures of the petrous bone, which were associated with ossicular dislocation in two patients. Transverse fractures were detected in six patients, with a contralateral mastoid fracture in one patient. In four patients, the fractures were restricted to the mastoid region. Of the 14 patients in whom adequate neurologic evaluation was available, seven had a permanent facial nerve or hearing deficit while five suffered at least a transient neurologic deficit related to the temporal bone trauma. Routine head CT (10 mm sections) demonstrated only eight of 19 petrous bone injuries. Clues to such injury included opacification of the mastoid air cells (10 patients), sphenoid sinus (11 patients), external canal and middle ear air space (10 patients), and local pneumocephalus (five patients). Evidence of brain trauma or extraaxial hematoma was seen in 12 patients. In 13 cases, high-resolution CT was also performed, demonstrating temporal bone injuries in all. This latter technique allows rapid and detailed evaluation of temporal bone trauma. Reports of radiographic evaluation of temporal bone trauma tend to deal with a somewhat skewed population, selected on the basis of clinical symptomatology. In a major trauma center equipped with high-resolution CT, it was found that temporal bone fractures may be seen incidentally, or in patients in whom symptomatology related to temporal fracture is obscured by much more serious neurologic compromise.     

Detection of unexpected additional primary malignancies with PET/CT.

This study evaluated the yield of whole-body (18)F-FDG PET/CT for the detection of unexpected (18)F-FDG-avid additional primary malignant tumors in patients being evaluated by PET/CT for known or suspected malignances. METHODS: Reports from whole-body (18)F-FDG PET/CT scans from June 2001 to June 2003 were reviewed, and 1,912 patients (924 men and 988 women; mean age +/- SD, 58.9 +/- 13.9 y) who had been scanned for known or suspected malignant lesions were included in this study. The sites of known or suspected primary tumors included lung (28.6%), colon or rectum (12.4%), head or neck (12.1%), lymph nodes (10.9%), breast (7.6%), gynecologic organs (7.1%), genitourinary organs (4.2%), esophagus (3.6%), skin (melanoma) (3.5%), pancreas (2.5%), bone or soft tissue (2.2%), and other sites (5.4%). Lesions that were newly discovered on PET/CT, had not been previously detected by other modalities, and were atypical in location for metastases on the PET/CT study were interpreted as suggestive of a new primary malignant tumor. These abnormalities were compared with the final diagnosis obtained from the medical records, including pathologic reports. RESULTS: PET-positive lesions suggestive of new primary malignant tumors were found in 79 (4.1%) of 1,912 patients. In 22 (1.2%) of 1,912 patients, these lesions were pathologically proven to be malignant. Proven sites were lung (7 lesions), thyroid (6 lesions), colon (4 lesions), breast (2 lesions), esophagus (2 lesions), bile duct (1 lesion), and head and neck other than thyroid (1 lesion). Two new lesions in the lung and the thyroid were proven malignant in 1 patient. In 17 patients, the treatment plan was changed and the new lesion was surgically resected after the PET/CT examination. In 10 patients, PET was falsely positive after pathologic assessment. False-positive sites included thyroid (5 lesions), uterus (2 lesions), head and neck other than thyroid (2 lesions), and lung (1 lesion). In 8 patients, the PET-positive lesions were considered benign after clinical follow-up of at least 8 mo. In 39 patients, the follow-up record was not yet available and the final diagnosis of the detected lesion has not yet been resolved. CONCLUSION: Whole-body PET/CT detected new, unexpected (18)F-FDG-avid primary malignant tumors in at least 1.2% of patients with cancer.     

Magnetic susceptibility artifacts on high-resolution MR of the temporal bone.

PURPOSETo determine whether signal variations and subtle anatomic deformities observed in high-resolution MR studies of temporal bones were caused by the large susceptibility differences at air-fluid interfaces near the round and oval window.METHODSA systematic study of healthy subjects and plastic phantoms was conducted. The phantom consisted of a series of cylindrical holes of various small sizes within a solid block of plastic. These holes were partially filled with water and then covered with a reservoir of gelatin to simulate the otic capsule air-water interfaces. On a 1.5-T system, T2-weighted fast spin-echo images and three-dimensional Fourier transform gradient acquisition in steady state images were obtained using dedicated phased-array radio frequency coils. The directions of the frequency and in-plane phase-encoding gradients were swapped, and the receiver bandwidth was changed to demonstrate the dependence of the artifacts on these parameters.RESULTSThe phantom images confirmed and characterized artifacts consistent with magnetic susceptibility differences at the air-water interfaces. There is a combination of signal loss, misregistration in the frequency-encoding direction, and high signal foci related to the air-water interfaces. Furthermore, the artifacts were worse with narrower receiver bandwidth. Similar consistent artifact patterns were seen near the oval and round windows in studies of healthy subjects.CONCLUSIONSIn high-resolution MR imaging there are significant deformities in the display of the normal anatomy because of magnetic susceptibility.     

MR and CT appearance of iliopsoas bursal distention secondary to diseased hips

Occasionally hip joint disease may extend into surrounding structures, including the retroperitoneum, via the iliopsoas bursa. The enlargement of this bursa may present as an inguinal or pelvic mass that may affect other surrounding structures and can result in a multitude of clinical presentations. The two cases presented herein of iliopsoas bursa distention secondary to hip disease demonstrate the excellent specificity of CT and magnetic resonance in differentiating this clinical entity from other causes of groin masses.