MR imaging of squamous cell carcinoma of the floor of the mouth. Appearance of the sublingual and submandibular glands.

PURPOSE: To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands. MATERIAL AND METHODS: Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. The appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively. RESULTS: All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images. CONCLUSION: At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images.     

Rathke cleft cysts: correlation of enhanced MR and surgical findings.

PURPOSETo describe the gadolinium-enhanced MR findings of Rathke cleft cyst correlate them with the surgical findings, and define those preoperative findings that differentiate this lesion from other sellar and juxtasellar tumors.METHODSWe studied 18 patients who were diagnosed as having Rathke cleft cyst pathologically. These patients were imaged with T1- and T2-weighted coronal and sagittal spin-echo sequences. Fifteen of these patients received gadopentetate dimeglumine.RESULTSIn eight patients, the cyst showed low intensity on T1-weighted images and high intensity on T2-weighted images. At surgery, the cyst fluid was cerebrospinal fluid-like or light brown in five patients, motor oil-like in one patient, and milky in two patients. In 10 patients, cysts showed isointensity to high intensity on T1-weighted images and had various intensity on T2-weighted images. All 10 contained milky fluid. In three patients the intensity of fluid was heterogeneous. A waxy nodule was found in two patients. The position of the normal pituitary gland confirmed by surgery in all cases coincided with enhancement on MR imaging. The variable position of the normal pituitary gland was clearly identified in the sagittal images. The cyst walls showed no enhancement by gadopentetate dimeglumine.CONCLUSIONSBecause Rathke cleft cysts show variable intensities on MR, the diagnosis is often difficult when based on MR signal intensity values alone. MR imaging with gadopentetate dimeglumine does assist in the diagnosis of Rathke cleft cysts. Diagnostic clues include the lack of cyst wall enhancement and displacement of the normal pituitary gland.     

Sublingual gland: MR features of normal and diseased states

OBJECTIVE: We describe the MR features of the sublingual gland in normal and diseased states. SUBJECTS AND METHODS: We used MR imaging to assess age-related changes in size and signal intensity of normal sublingual glands in 60 control subjects. The MR features of sublingual glands were also studied in 70 patients with cancer, cellulitis of the sublingual space, Sj?gren's syndrome, or ranula. RESULTS: MR imaging efficiently revealed normal sublingual glands. On T1-weighted images, the MR signal intensity of the sublingual gland was lower than that of the surrounding fat but higher than that of muscle. The sublingual glands showed age-related decreases in size, with approximately 25% of the thickness present in the second decade of life being lost by the seventh decade. T1-weighted signal intensity of the parotid gland increased with age, but the signal intensity of the sublingual and submandibular glands did not. T1-weighted signal intensity of carcinomas in and near the sublingual space was lower than that of the sublingual glands, but T2-weighted signal intensity of carcinomas exceeded that of the glands. Gadolinium enhancement occasionally diminished the contrast between invading carcinomas and the glands. T1-weighted MR imaging showed that sublingual glands affected by Sj?gren's syndrome exhibit features analogous to those of the other major salivary glands; however, the sublingual glands seemed to be less severely involved overall in this syndrome than the other major glands. We found that using fat suppression and short inversion time inversion recovery may be useful for assessment of sialadenitis of the gland. CONCLUSION: MR imaging is useful in depicting normal and diseased states of the sublingual gland.     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

A case of synovial sarcoma in the submandibular region

Synovial sarcomas are a less common cervical tumor in young patients. We report a 23-year-old man with synovial sarcoma in the submandibular region. T2-weighted MR images demonstrated a mixed-intensity tumor attached to the submandibular gland. T1-weighted MR images revealed a focal area with mildly increased signal intensity, indicating intratumoral hemorrhage. MR images were also useful for visualization of tumor extension. Synovial sarcoma should be considered in the differential diagnosis of well-defined inhomogeneous tumors adjacent to the submandibular gland in young adults.     

MR of denervated tongue: temporal changes after radical neck dissection.

PURPOSEThe purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection.METHODSOne hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study.RESULTSAbnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery.CONCLUSIONMR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.     

Imaging of pancreatic neoplasms: comparison of MR and CT

Thirty-two patients with pathologically proved pancreatic carcinomas or cystadenomas were evaluated with MR images obtained with T1-weighted spin echo (short TR/short TE), inversion recovery, and T2-weighted spin-echo (long TR/long TE) pulse sequences. CT was used as the reference standard to determine the ability of MR to delineate normal and abnormal pancreatic anatomy and thereby to exclude or detect pancreatic malignancy. Short TR/short TE spin-echo sequences were significantly better (p less than .05) than inversion recovery or T2-weighted spin-echo sequences in resolution of both normal and abnormal anatomy. Resolution of pancreatic anatomy correlated (r = .9) with the image signal-to-noise ratio. In seven (22%) of 32 cases, MR visualized pancreatic tumors better than CT did because it showed a signal intensity difference between the tumor and normal pancreatic tissue. Overall, the slight superiority of MR over CT for tumor visualization tended to occur in larger tumors and was not statistically significant. On T1-weighted images, 63% (20 of 32) of pancreatic tumors studied had lower signal intensities than normal pancreatic tissue, whereas on T2-weighted sequences (TE = 60, 120, and 180 msec) only 41% (13 of 32) of tumors had increased signal intensities. Currently available MR imaging techniques offer no significant advantages over CT for evaluating the pancreas for neoplasia.     

Intracranial tuberculoma: comparison of MR with pathologic findings.

PURPOSETo compare the MR signal intensity patterns and enhancement pattern of intracranial tuberculomas with their histopathologic features.METHODSMR images of six patients with surgically proved intracranial tuberculoma were reviewed retrospectively and were compared with histologic findings of the resected specimen. Detailed histologic examination was performed to look for the extent and characteristics of caseation necrosis, fibrosis, and inflammatory cellular infiltrates at each area of different signal intensities and at the enhancing areas on MR. Signal intensities for T1- and T2-weighted images were compared with normal gray matter.RESULTSOn T1-weighted images, the granulomas showed a slightly hyperintense rim surrounded by a complete or partial rim of slight hypointensity and central isointensity or mixed isointensity and hyperintensity in five patients and homogeneous isointensity in one patient. Histologically, the zone of central isointensity or mixed intensity corresponded to caseation necrosis plus adjacent cellular infiltrates. The hyperintense and hypointense rims corresponded to the layers of collagenous fiber and the layers of the inflammatory cellular infiltrates, respectively. On T2-weighted images, the entire portion of the granuloma showed slightly heterogeneous isointensity or hypointensity with small markedly hypointense foci in five patients, and a hyperintense center surrounded by a hypointense rim in one patient. Histologic layers were not discriminated on T2-weighted images. On postcontrast T1-weighted images, there were single or multiple conglomerate ring enhancements within a tuberculoma in all six patients, corresponding to the layers of both collagenous and inflammatory cells.CONCLUSIONCombination of the described signal intensity patterns and conglomerate ringlike enhancing appearance of the lesion is characteristic of tuberculoma, and may play an important role in differentiating intracranial tuberculomas from other ring-enhancing brain lesions.     

MR imaging findings of Rathke's cleft cysts: significance of intracystic nodules

BACKGROUND AND PURPOSE: Rathke's cleft cysts often may be difficult to differentiate from other intrasellar or suprasellar masses on radiologic studies. The purpose of this study was to describe the significance of intracystic nodules, a diagnostic characteristic found in Rathke's cleft cysts, on MR images. METHODS: A retrospective review of MR studies was conducted for 13 patients who, after pathologic analysis, were diagnosed as having Rathke's cleft cyst. These patients underwent unenhanced and contrast-enhanced T1- and T2-weighted axial and coronal spin-echo sequential imaging. The signal intensity and incidence of the intracystic nodules on T1- and T2-weighted images were analyzed. The signal intensity of the nodule was compared with that of white matter and surrounding cyst fluid. The signal intensity of cyst fluid was compared with the intraoperative appearance of the cyst fluid. Biochemical and pathologic analyses of the intracystic nodules were conducted in two cases. RESULTS: An intracystic nodule having high signal intensity on T1-weighted images and low signal intensity on T2-weighted images was observed in 10 (77%) of the cases. At surgery, intracystic nodules were yellow, waxy, solid masses. Pathologic analysis showed this nodule to be a mucin clump. Biochemical analysis of the intracystic nodules showed cholesterol and proteins as the main constituents. In the Rathke's cleft cyst with intracystic nodules, cyst fluid revealed low signal intensity to isointensity relative to the intensity of the nodules on T1-weighted images, and isointensity to high signal intensity on T2-weighted images. Intracystic nodules were clearly visible on T2-weighted images. CONCLUSION: Because cyst fluid of Rathke's cleft cysts shows variable intensities on MR images, the specific diagnosis is often difficult when based on MR signal intensity values alone. The presence of an intracystic nodule with characteristic signal intensities on MR images may be indicative of the diagnosis of Rathke's cleft cyst.     

Triangular fibrocartilage and intercarpal ligaments of the wrist: MR imaging. Cadaveric study with gross pathologic and histologic correlation

To provide further understanding of the magnetic resonance (MR) signal intensities in the triangular fibrocartilage (TFC) and interosseous ligaments of the wrist, the authors performed MR imaging with gross pathologic and histologic analysis in 10 cadaveric wrists. Spin-echo T1- and T2-weighted coronal images were obtained, and 3-mm coronal sections of the specimens were then made that correlated precisely with the MR images. Normal portions of the TFC showed asymmetrical bow tie-like low signal intensity, except near the radial and ulnar attachments. Degeneration of the TFC, present in all cases, was more severe on the proximal surface and was characterized by high signal intensity on T1-weighted images and less high signal intensity on T2-weighted images. These findings differed from those in TFC perforation, which showed high signal intensity on T2-weighted images. Similar signal intensity characteristics could allow differentiation of degeneration and perforation of the scapholunate and lunotriquetral ligaments. These findings suggest that in vivo MR imaging may accurately delineate degeneration and perforation of the TFC and intercarpal ligaments.     

Bone bruises: MR characteristics and histological correlation in the young pig

PURPOSE: To correlate magnetic resonance (MR) signal characteristics of bone bruises with histological findings. MATERIALS AND METHODS: In 14 tibiae of young pigs, bone bruises were created in the proximal tibial metaphysis. The signal intensity seen on the MR images were correlated with histological findings. The following findings were evaluated: (a) changes of signal intensity on the tibiae; (b) changes of histology on the tibiae; and (c) changes of (a) and (b) on follow-up examinations. RESULTS: We observed three types of injuries on T1-weighted images: focal or diffuse low signal, normal signal and linear low signal intensities. Severe hemorrhagic areas showed low signal intensities on all sequences of MR imaging. Fast spin-echo (FSE) T2-weighted images showed a more distinct low signal intensity than T1-weighted images. FSE short tau inversion recovery (STIR) and FSE fat saturated (FSE-FS) T2-weighted images showed similar signal intensities with FSE T2-weighted images. FS T1-weighted enhanced images showed low signal intensities with variable enhancements. Upon histological examination, hemorrhages and edemas were prominent at the subcortical areas of the contusion sites. The areas of dense, low signal intensities in all imaging sequences showed signs of severe hemorrhage. The areas of diffuse low signal and enhanced areas showed mixed areas of hemorrhages and edemas. Follow-up MR imaging showed evolution of the processes of hemorrhages and edemas with fatty marrow changes. CONCLUSIONS: MR imaging can depict changes in the bone marrow resulting from direct injury to the bone. MR imaging is a useful tool for evaluating the evolution of bone bruises.     

Warthin tumor of the parotid gland: diagnostic value of MR imaging with histopathologic correlation

BACKGROUND AND PURPOSE: The purpose of our study was to describe the MR imaging appearance of Warthin tumors multiple MR imaging techniques and to interpret the difference in appearance from that of malignant parotid tumors. METHODS: T1-weighted, T2-weighted, short inversion time inversion recovery, diffusion-weighted, and contrast-enhanced dynamic MR images of 19 Warthin tumors and 17 malignant parotid tumors were reviewed. MR imaging results were compared with those of pathologic analysis. RESULTS: Epithelial stromata and lymphoid tissue with slitlike small cysts in Warthin tumors showed early enhancement and a high washout rate (> or =30%) on dynamic contrast-enhanced images, and accumulations of complicated cysts showed early enhancement and a low washout ratio (< 30%). The areas containing complicated cysts showed high signal intensity on T1-weighted images, whereas some foci in those areas showed low signal intensity on short tau inversion recovery images. The mean minimum signal intensity ratios (SIRmin) of Warthin tumor on short tau inversion recovery (0.29 +/- 0.22 SD) (P < .01) and T2-weighted images (0.28 +/- 0.09) (P < .05) were significantly lower than those of malignant parotid tumors (0.53 +/- 0.19, 0.48 +/- 0.19). The average washout ratio of Warthin tumors (44.0 +/- 20.4%) was higher than that of malignant parotid tumors (11.9 +/- 11.6%). The mean apparent diffusion coefficient of Warthin tumors (0.96 +/- 0.13 x 10(-3)mm2/s) was significantly lower (P < .01) than that of malignant tumors (1.19 +/- 0.19 x 10(-3)mm2/s). CONCLUSION: Detecting hypointense areas of short tau inversion recovery and T2-weighted images or low apparent diffusion coefficient values on diffusion-weighted images was useful for predicting whether salivary gland tumors were Warthin tumors. The findings of the dynamic contrast-enhanced study also were useful.     

Malignant lymphoma of the gingiva: MR evaluation.

PURPOSEOur purpose was to document the MR imaging findings of malignant lymphoma of the gingiva.METHODSFive patients with histologically proved malignant lymphoma of the gingiva were studied by MR imaging. The MR images were analyzed for tumor size, extent, and signal characteristics, bone involvement, and associated cervical lymph node enlargement.RESULTSClinical examination tended to underestimate the size of lymphomatous lesions. The signal intensity of the lesions was isointense to hyperintense relative to muscle on noncontrast T1-weighted images and showed variable contrast enhancement patterns. On T2-weighted images, signal intensity was isointense to hypointense relative to the oral mucosa. In one case, the mass extended to the submandibular space; in the remaining cases, the masses were limited to the gingiva and the adjacent bone. MR imaging revealed that gingival lymphomatous masses were broad-based along the mandible or maxilla and eroded through the cortex into the marrow space, but the cortex was still recognizable. No nodal involvement was noted in any of the patients with malignant lymphoma.CONCLUSIONThe signal characteristics of gingival lymphoma overlap those of other tumors. The cortex separating marrow involvement from the broad-based gingival mass generally appears to be permeated with small erosions but is still recognizable.     

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.     

Colorectal mucinous carcinoma: findings on MRI

PURPOSE: The purpose of this work was to define the characteristic MR features of colorectal mucinous carcinomas and to correlate the mucin pool with the signal intensity of this tumor. METHOD: MRI of 12 cases of pathologically proven colorectal carcinoma containing mucin was evaluated. We analyzed the signal intensity of tumor on T1- and T2-weighted MR images and correlated the area of intratumoral high signal intensity on T2-weighted images with the mucinous pool on the pathologic specimens. Two radiologists independently estimated the area of high signal intensity in the tumor on T2-weighted images and one pathologist estimated the amount of mucinous pool in the pathologic specimen. RESULTS: In 9 (75%) of 12 cases, focal or diffuse high signal intensity areas were detected on T2-weighted fast spin echo images. In seven cases in which mucin pools were seen macroscopically, partial (n = 3) or diffuse high signal intensity areas were noted on the T2-weighted images. Among the five cases in which microscopic mucinous pools were detected on the pathologic slides, three cases showed no high signal foci on MR images, and in the remaining two cases, high signal intensity areas were noted as small foci. CONCLUSION: Intratumoral high signal intensity on T2-weighted fast spin echo MR images occurs in mucinous carcinomas and correlates with the mucin pools on pathologic specimens.     

MR imaging features of pure mucinous carcinoma of the breast

ObjectiveTo characterize MR imaging features of pure mucinous carcinoma of the breast.Materials and methodsMR images obtained from 16 women (age range, 29–81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings.ResultsEleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass.ConclusionsMR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.     

Salivary duct carcinomas: clinical and CT and MR imaging features in 20 patients

Introduction

Salivary duct carcinoma (SDC) is an uncommon high grade adenocarcinoma of the salivary gland with a grave prognosis. The aim of this study was to investigate the clinical and CT and MR imaging features of SDC.

Methods

We retrospectively evaluated the clinical and CT and MR imaging findings in 20 patients (14 men and six women; mean age, 59?years) with histologically proved SDC. We also tried to correlate clinicoradiological tumor staging with pathologic tumor staging in 17 patients who underwent surgery.

Results

The tumor originated in the parotid gland (n?=?11; 55%), the submandibular gland (n?=?7; 35%) and the buccal space along the distal Stensen's duct (n?=?2; 10%). Locoregional recurrence occurred in 41% and distant metastasis in 47%. Fifty-eight percent died of the disease with a mean survival period of 32?months after diagnosis. On CT and MR images, SDC was mostly seen as an ill-defined (85%) and infiltrative (60%) mass with frequent calcification (50%) and necrosis (80%). Although various signal intensities were seen on MR images, six of nine tumors contained the areas of marked hypointensity on T2-weighted images. Clinicoradiological tumor staging correlated well with pathologic tumor staging in 82% of the patients.

Conclusion

Ill-defined, infiltrative mass with calcification on CT scans and the areas of marked hypointensity on T2-weighted MR images may be useful radiologic features to suggest the diagnosis of SDC. CT and MR imaging are useful for staging of SDC.     

MRI of chronic sclerosing sialoadenitis

The purpose of our study was to describe the MR appearance of Kuttner's tumours and to interpret their differences in appearance from other submandibular gland tumours. MR studies of 7 Kuttner's, 8 malignant and 12 benign submandibular gland tumours were reviewed. MR sequences obtained included T(1) weighted, short inversion time inversion recovery (STIR), T(2) weighted, diffusion-weighted (DW) and dynamic contrast-enhanced MR (dynamic MR) images. In all cases of Kuttner's tumour, the affected submandibular glands were swollen with slightly higher intensity on T(2) weighted, STIR and DW images, but the tumour margin could not be defined. Conversely, the margins of the other tumours could be detected. On T(2) weighted, STIR and DW images, the mean signal intensity ratios and the mean apparent diffusion coefficient (ADC) values for Kuttner's tumours and malignant tumours were significantly lower than those of benign tumours, but there were no significant differences between those of Kuttner's tumours and those of malignant tumours. All benign tumours showed late enhancement, with peak enhancement later than 120 s on dynamic MR images. Kuttner's tumours and malignant tumours showed variable enhancement patterns. In conclusion, signal intensity ratios for T(2) weighted and STIR images, ADC values and patterns of enhancement may help distinguish Kuttner's tumours from benign submandibular gland tumours, but not from malignant tumours. Although the intensities, ADC values and enhanced patterns of Kuttner's tumours were similar to those of malignant tumours, there were some morphological differences.     

Testes and scrotum: MR imaging at 1.5 T

Magnetic resonance (MR) images of the scrotum were obtained at 1.5 T in 20 subjects, 13 patients with intrascrotal pathologic conditions and seven healthy subjects. Characteristic MR imaging signals obtained on T1- and T2-weighted images allowed differentiation of testis from epididymis and spermatic cord. Masses were differentiated from normal testicular parenchyma in all cases. Atrophic or ischemic testes had lower signal intensity than normal testes on T2-weighted images. Hematoma displayed a characteristic high intensity on both T1- and T2-weighted images. Intratesticular and extratesticular pathologic conditions were readily differentiated. These results suggest that MR imaging is useful in the diagnosis of scrotal and testicular abnormalities.     

Basal cell adenoma of the parotid gland: MR imaging findings with pathologic correlation

BACKGROUND AND PURPOSE: Basal cell adenomas (BCAs) are rare tumors of the parotid gland. Only a few case reports describing MR imaging features of BCA have been published. The aim of this study was to describe and characterize the MR findings of BCAs of the parotid gland. MATERIALS AND METHODS: We retrospectively reviewed MR images of BCA with pathologic correlation in 8 cases (2 men and 6 women; age range, 52-82 years) collected between January 1992 and August 2004 from our pathologic data base. All MR images were retrospectively evaluated with respect to the marginal morphology, signal intensity (SI), and enhancement behavior by 2 experienced radiologists. RESULTS: On pathologic examination, 5 tumors were solid type, 2 were trabecular type, and 1 was membranous type. All of the tumors were well circumscribed with smooth contours. Cystic changes were seen in 4 cases. On T1-weighted images (T1WI), 7 tumors showed homogeneously low SI equal to muscle and one showed heterogeneously low SI. On T2-weighted images (T2WI), all of them showed slightly lower SI than that of surrounding parotid tissue. On gadolinium-enhanced T1WI, 6 tumors demonstrated moderate enhancement and one demonstrated strong enhancement (membranous type). Dynamic studies were performed in 4 cases. All showed rapid and prolonged enhancement. CONCLUSION: MR imaging findings of BCA were well-defined and smooth marginal morphologies, relatively low SI on both T11W and T2WI, and rapid and prolonged enhancement on dynamic study. Although BCAs are rare, they should be suspected when a tumor shows all of the characteristics noted here.