Peripheral Ring-like Enhancement Research Articles

Diagnostic value of morphological enhancement patterns in the hepatobiliary phase of gadoxetic acid-enhanced MRI to distinguish focal nodular hyperplasia from hepatocellular adenoma.

To describe the different morphological enhancement patterns of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI (Gd-EOB-DTPA MRI) and to determine their added value in their differential diagnosis. A retrospective analysis of imaging findings in 185 benign hepatocellular lesions (154 FNH; 31 HCA) in 108 patients who underwent Gd-EOB-DTPA MRI was performed by two independent reviewers. Six patterns on HBP were recorded: 1) homogeneous enhancement; 2) peripheral ring-like enhancement with hypointense central core; 3) peripheral ring-like enhancement with hyperintense central core; 4) central core enhancement with hypointense periphery; 5) heterogeneous enhancement; and 6) the absence of enhancement. Peripheral ring-like enhancement with hypointense central core and peripheral ring-like enhancement with hyperintense central core showed the highest specificity for the diagnosis of FNH (100% and 96.8%, respectively). The absence of enhancement and central core enhancement with hypointense periphery were only present in 0.6% and 1.9% of FHN, respectively. All other patterns were observed with similar frequencies in FNH (22.1% to 26.6%). Six HCA showed contrast uptake on the HBP: homogeneous (6.5%), peripheral ring-like enhancement with hyperintense central core (3.2%) and heterogeneous (9.7%). Both FNH and HCA may demonstrate enhancement in the HBP of Gd-EOB-DTPA MRI, limiting its specificity. A significant improvement in specificity can be achieved by the evaluation of morphological enhancement patterns: Peripheral ring-like enhancement with hypointense or hyperintense central core was highly specific for FNH diagnosis. On the other hand, the absence of HBP enhancement makes the diagnosis of FNH unlikely.

Value of contrast-enhanced malignancy imaging features in secondary grade diagnosis of BI-RADS-US type 4 breast lesions.

To explore the value of contrast-enhanced malignancy imaging features in secondary grade diagnosis of Breast Imaging Reporting and Data System for Ultrasonography (BI-RADS-US) type 4 breast lesions. After initial diagnosis by ultrasound, 124 BI-RADS-US type 4 patients with 130 lesions were examined by contrast-enhanced ultrasound (CEUS) and were classified again before surgery according to five contrast-enhanced malignancy imaging features: inhomogeneous enhancement, peripheral ring-like enhancement, expansive enhancement, internal filling defects, and surrounding radioactive convergence. Lesions with no contrast-enhanced features of malignancy were categorized as type 3; lesions with one, two, or three features of malignancy were categorized as type 4A, 4B, or 4C, respectively; and lesions with four or more indices of malignancy were categorized as type 5. The value of contrasted imaging features of malignancy in diagnosing BI-RADS-US type 4 breast lesions was analyzed. The accuracy of CEUS diagnosis for type 3 lesions was 93.8% (46/49), 76.9% (10/13) for type 4A, 71.4% (5/7) for type 4B, 75.0% (9/12) for type 4C, and 93.8% (46/49) for type 5 lesions. The sensitivity of CEUS in diagnosing malignant lesions was 90.4%, specificity was 83.6%, and accuracy was 86.9%. CEUS decreased the benign lesion biopsy ratio to 68.5% (46/67) and increased the diagnosis ratio of malignant lesions to 73.0% (46/63). CEUS can further optimize the classification of BI-RADS-US type 4 breast lesions and may provide a better reference basis for clinical diagnosis and treatment of those breast lesions.

Typical CT and MRI signs of hepatic epithelioid hemangioendothelioma.

To investigate the typical magnetic resonance imaging (MRI) and computed tomography (CT) features of hepatic epithelioid hemangioendothelioma (HEH), the CT and MRI findings of 14 histopathologically confirmed cases of HEH were retrospectively analyzed. Non-contrast and dynamic contrast-enhanced scans were conducted in all cases. A total of 229 lesions were detected in the 14 cases. All cases were classified as one of three types: (i) Solitary nodular type (1 case, 7%); (ii) multifocal nodular type (11 cases, 79%); or (iii) diffuse type (2 cases, 14%). The diameter of the lesions ranged from 5 to 105 mm. For the first two types (solitary and multifocal nodular types), the CT findings included low density lesions with clear margins on non-contrast scans, centripetal enhancement in arterial phase, and homogeneous enhancement in the portal venous and delay phases. The findings of non-contrast MRI scans for these two types included low signal intensity on T1-weighted images, heterogeneous high signal intensity on T2-weighted images, and heterogeneous high signal intensity on diffusion-weighted images. The lesions were predominantly located in submarginal areas. On contrast-enhanced MRI, the findings for the first two types included peripheral ring-like enhancement with a central low signal intensity (‘black target-like’ sign) and a central enhanced core surrounded by a low signal intensity halo (‘white target-like’ sign). The findings for the third HEH type (diffuse type) on CT and MRI scans included low density or heterogeneous signal intensity lesions involving regions of part or the whole liver, coalescent lesions (‘strip-like’ sign), and gradual enhancement along central vessels (‘lollipop’ sign). Collectively, these findings indicate that the ‘white target-like’ sign, ‘black target-like’ sign, ‘lollipop’ sign and ‘strip-like’ sign, in addition to capsular contraction and submarginal location, on CT and MRI imaging may have implications for the diagnosis of HEH. Furthermore, a variety of MRI sequences may provide additional information for the differential diagnosis of HEH.

Atypical Findings of Focal Nodular Hyperplasia with Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced Magnetic Resonance Imaging

We report two cases of focal nodular hyperplasia in patients following gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging confirmed with histopathology. These cases showed an atypical pattern during the delayed-hepatobiliary phase after the injection of gadoxetic acid. One case showed a total defect, and the other showed a peripheral ring-like enhancement without a visible central scar, mimicking hepatocellular carcinoma. The pathologic examination demonstrated that the two lesions were focal nodular hyperplasia.

Epithelioid hemangioendothelioma adjacent to the axilla: a case report

We described a case of a 71-year-old woman with an epithelioid hemangioendothelioma (EHE) in her left axilla, a rare location which hasn’t been reported yet. The patient suffered from numbness, pain and decreased muscle strength of her left upper extremity. Sonography revealed a hypoechoic mass surrounded the axillary artery and brachial artery. No obvious capsule was demonstrated. CT showed a soft-tissue mass with some calcifications and peripheral ring-like enhancement. The MRI indicated a mass with mainly intermediate signal intensity on T1-weighted imagine and intermediate signal intensity on T2-weighted imagine. The diagnosis was confirmed by histopathologic examination after surgery. There are some correlations of these imaging features with its histopathologic characters.

Differentiation of focal liver lesions using three-dimensional ultrasonography: Retrospective and prospective studies

To differentiate focal liver lesions based on enhancement patterns using three-dimensional ultrasonography (3D US) with perflubutane-based contrast agent. Two hundred and eighty two patients with focal liver lesions, including 168 hepatocellular carcinomas (HCCs), 63 metastases, 40 hemangiomas and 11 focal nodular hyperplasias (FNHs), were examined by 3D US with perflubutane-based contrast agent. Tomographic ultrasound images and sonographic angiograms were reconstructed. Among 282 lesions, enhancement patterns of 163 lesions between January 2007 and October 2007 were analyzed retrospectively. Then from November 2007 to May 2008, compared with contrast-enhanced (CE) 2D US, CE 3D US was performed on 119 lesions for prospective differential diagnosis. Sensitivity, specificity, area under receiver operating characteristic curve (A(z)) and inter-reader agreement were assessed. With the tridimensional view, dominant enhancement patterns were revealed as diffuse enhancement or peripheral ring-like enhancement, followed with washout change for HCCs or metastases, respectively, and peripheral nodular enhancement or diffuse enhancement with spoke-wheel arteries, followed by persistent enhancement for hemangiomas or FNHs, respectively. At CE 3D US, the prospective differentiation of lesions showed sensitivity 92% (mean for two readers), specificity 91% and A(z) value 0.95 for HCCs, 84%, 97%, and 0.95 for metastases, 91%, 98%, and 0.98 for hemangiomas and 80%, 99%, and 0.99 for FNHs, respectively, while good to excellent inter-reader agreement was achieved. No significant difference exists between prospective diagnosis accuracy at CE 3D US and that at CE 2D US. CE 3D US provides a spatial perspective for liver tumor enhancement, and could help in differentiating focal liver lesions.

Sonazoid-Enhanced Ultrasonography for Evaluation of the Enhancement Patterns of Focal Liver Tumors in the Late Phase by Intermittent Imaging With a High Mechanical Index

The purpose of this study was to evaluate the enhancement patterns of focal liver tumors in the late phase of Sonazoid-enhanced ultrasonography by intermittent imaging with a high mechanical index (MI). A total of 142 patients with 208 lesions, including 109 hepatocellular carcinomas (HCCs), 61 metastases, 30 hemangiomas, and 8 focal nodular hyperplasias (FNHs), were enrolled in this prospective study. Contrast-enhanced ultrasonography with intermittent scanning at 2 frames per second (MI, 0.7-1.2) was conducted in the late phase (>5 minutes after bolus intravenous injection of the perflubutane-based contrast agent Sonazoid; Daiichi Sankyo, Tokyo, Japan). Two blinded readers classified the enhancement patterns of the lesions. The sensitivity, specificity, and positive predictive value (PPV) of the dominant enhancement patterns and inter-reader agreement were assessed. A combination of diffuse enhancement with intratumoral vessels and intratumoral vessels alone yielded sensitivity of 85% (average of both readers), specificity of 88%, and a PPV of 88% for HCC. For metastasis, a combination of peripheral ringlike enhancement with peritumoral vessels and peripheral ringlike enhancement with intratumoral vessels yielded sensitivity of 79%, specificity of 95%, and a PPV of 85%. For hemangiomas, a combination of peripheral nodular enhancement with peritumoral vessels and peripheral nodular enhancement without peritumoral vessels yielded sensitivity of 75%, specificity of 99%, and a PPV of 92%. Diffuse enhancement with spoked wheel arteries yielded sensitivity of 82%, specificity of 100%, and a PPV of 87% for FNHs. Good inter-reader agreement was achieved. Sonazoid-enhanced ultrasonography using intermittent imaging with a high MI can potentially be used for evaluating the enhancement patterns of focal liver tumors in the late phase.

Magnetic Resonance Imaging Features of Spontaneously Regressed Thymoma

The authors describe 2 cases in which thymoma spontaneously regressed. The first patient was a 49-year-old woman with myasthenia gravis. A chest radiograph on admission showed an anterior mediastinal mass that spontaneously decreased in size as shown on a radiograph obtained 2 weeks later. Surgical removal of the mass was performed and the histopathologic examination showed a type B2 thymoma with marked coagulation necrosis in the central area. The second patient was a 46-year-old woman who was hospitalized due to chest and back pain. A chest radiograph on admission showed an anterior mediastinal mass and bilateral pleural effusion. The mass decreased in size and the effusion disappeared as shown on a chest radiograph obtained 2 months later. Computed tomography-guided biopsy was performed, and histopathologic examination revealed thymoma with marked necrosis. In both cases, dynamic contrast-enhanced magnetic resonance images showed peripheral ringlike enhancement of the mass. The clinical and radiologic features of spontaneously regressed thymoma may be different from those of common thymoma.

Aspiration biopsy of nodular sarcoidosis of the muscle No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis. Diagn. Cytopathol. 2002;26:109–112; DOI 10.1002/dc.10055 © 2002 Wiley-Liss, Inc.

Aspiration biopsy of nodular sarcoidosis of the muscle

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis.

Role and limitation of FMPSPGR dynamic contrast scanning in the follow-up of patients with hepatocellular carcinoma treated by TACE.

To evaluate the role and limitation of fast multiplanar spoiled gradient-recalled (FMPSPGR) MR dynamic contrast scanning in the follow-up of patients with HCC treated by transarterial chemoembolization (TACE). Twenty-two patients with 24 HCC lesions confirmed by biopsy or surgical resection underwent MR imaging in 4-9wks after TACE with a superconducting 1.5 T MR scanner, including SE T(1)WI, T(2)WI and FMPSPGR dynamic contrast scanning. The signal intensities of all lesions on SE T(1)WI,T(2)WI and the enhancement patterns on FMPSPGR dynamic contrast scanning were observed, and the comparison was made between MRI findings and pathological results in all the cases. Of the 24 lesions, the signal intensities were various on SE T(1)WI and T(2)WI. On T(1)WI, 13 lesions appeared as hyperintense, 4 lesions were isointense and the other 7 lesions were hypointensese. Histologically, hyperintense lesions showed on T(1)WI were viable tumor or hemorrhage; isointensities were coagulative necrosis or inflammatory infiltration; hypointensities were tumor, liquified necrosis, coagulative necrosis or inflammatory infiltration. On T(2)WI, 15 lesions appeared as hyperintense, 3 lesions were isointense and the other 6 lesions were hypointensese. Hyperintense lesions showed on T(2)WI were residuals of viable tumor, hemorrhage, liquefied necrosis or inflammatory infiltration; isointense lesions were residuals of viable tumor or inflammatory infiltration; hypointense lesions were coagulative necrosis. On FMPSPGR dynamic contrast scanning, 18 of the 24 lesions enhanced on early-phase dynamic scanning corresponding to residuals of viable tumor and the other 6 lesions had no enhancement at this phase because complete necrosis were seen in the histologic examination. On delayed-phase dynamic scanning, 6 lesions had permanent enhancement appeared as inhomogeneous hyperintensity and both residuals of viable tumor and inflammatory infiltration were found by histologic examination. 18 lesions were hypointense at this phase and 8 of them coexisted with peripheral ring-like enhancement of the lesions resulting from viable tumors or inflammatory infiltration. FMPSPGR MR dynamic contrast scanning can reflect the pathologic changes of HCC treated by TACE. Especially, early-phase dynamic scanning can evaluate accurately residuals of viable tumor and necrosis in HCC lesions. FMPSPGR dynamic contrast scanning is useful in the follow-up of patients with HCC treated by TACE combined with SE T(1)WI and T(2)WI, but it is difficult to differentiate peripheral viable tumors from inflammatory infiltration.

Giant Cell Tumor (Osteoclastoma) of the Petrous Bone: Case Report

A case of a basal middle fossa giant cell tumor occurring in a 46-year-old man is described. The lesion appeared at the computed tomography (CT) scan examination as an hypodense mass with a peripheral "ring-like" enhancement, and no evident erosion of the skull base. The tumor, which infiltrated the basal temporal parenchyma, was removed via a temporal transzygomatic craniotomy, and extensive drilling of the petrous bone. Despite the occurrence, of significant postoperative complications, the patient ultimately showed a good clinical outcome, with no signs of recurrence at the 1-year follow-up CT scanning. The clinical and diageostic aspects and the management policy, of this rare lesion are discussed.

Tuberculous brain abscess: A case report and review of the literature

We present the case of a 21-year-old male patient who, despite triple antituberculosis therapy, developed a right frontal hypodense expansive process which exhibited peripheral ring-like enhancement following intravenous contrast injection. With the diagnosis of tuberculous brain abscess, we performed complete extirpation by means of craniotomy. The clinical suspicion was confirmed histologically. Patient's evolution has been satisfactory, and he remains asymptomatic at the present time.

Islet cell tumors: comparison of dynamic contrast-enhanced CT and MR imaging with dynamic gadolinium enhancement and fat suppression.

Ten patients with 11 islet cell tumors underwent dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging within a 1-month period. MR imaging depicted all 11 tumors, and CT depicted seven of the 11 tumors. CT did not depict four of seven tumors that measured 2.5 cm in diameter or less. Islet cell tumors had low signal intensity on T1-weighted fat-suppressed MR images, and gastrinomas were best shown with this technique. Two of three insulinomas less than 1.5 cm in diameter were best shown on dynamic contrast-enhanced fast low-angle shot (FLASH) images as uniform areas of high signal intensity. Hepatic metastases were seen in five patients and showed peripheral ringlike enhancement best demonstrated on dynamic gadolinium-enhanced FLASH images. Hepatic lesions were most conspicuous on T2-weighted fat-suppressed spin-echo images. MR imaging with dynamic gadolinium enhancement and fat suppression is a promising tool in the investigation of islet cell tumors.

The Unusual Association of Transient Resolving Thyrotoxicosis due to Painless Thyroiditis, Hypopituitarism and Central Diabetes Insipidus Associated with Spontaneous Pituitary Apoplexy

Pituitary apoplexy is characterized by a wide spectrum of clinical features. A quite rare case of painless thyroiditis, hypopituitarism and central diabetes insipidus (DI) followed by pituitary apoplexy was presented. A 61-year-old woman was admitted to our hospital in May, 1986 because of marked general malaise, polydipsia and weight loss which became progressively worse. Four months earlier she had experienced episodes of abrupt onset of severe headache associated with nausea and blurring vision. Physical examinations revealed a fine tremor, dry skin and nervousness. The thyroid gland was not palpable. Visual fields were intact. Her blood pressure was 105/64 mmHg with variable tachycardia. The routine laboratory studies were normal or negative except for hypoalbuminemia, hypocholesterolemia and hypernatremia. Erythrocyte sedimentation rate was 12 mm/hr. An impairment in corticotropin secretion was suspected from the low plasma cortisol and the low urinary excretion of 17-OHCS and the sufficient response to ACTH. Basal levels of GH and gonadotropin were also low, and responses to the stimulation tests (Insulin-stress, L-DOPA, and LH-RH) were all blunted. Brain computed tomographic scan and magnetic resonance imaging demonstrated a suprasellar mass that, after infusion, developed peripheral ring-like enhancement and large hyperintense pituitary mass, respectively. A diagnosis of pituitary apoplexy with anterior pituitary failure was made. However, the initial levels of thyroid hormones showed elevated as follows: Free T3 7.6 pg/ml, Free T4 3.3 ng/dl and T3-resin uptake 41.1%. TSH responses to TRH were all suppressed. TSH receptor antibody (TBII) was negative. Both antithyroglobulin and antimicrosomal antibodies were repeatedly positive. A thyroid scan with 99mTc revealed no uptake in the thyroid area. These findings led us to the diagnosis of "painless autoimmune thyroiditis". She had become hypothyroid without any medication. At that time radioactive 99mTc and 123I uptakes increased significantly. When hydrocortisone was substituted, daily urine output abruptly increased to about 10 liters with low osmolality, and the presence of DI was suspected. This diagnosis was confirmed by water deprivation and hypertonic saline infusion tests and subsequent pitressin test. She is currently quite well on L-thyroxine, hydrocortisone and desmopressin (1988). This association with pituitary apoplexy must be a rare occurrence, as a literature search has failed to find a similar case. The pathogenetic trigger of "painless thyroiditis" in this case may be responsible for some immunological change due to secondary adrenal insufficiency after pituitary apoplexy.

Pituitary Apoplexy

In two patients with pituitary apoplexy, computerized tomograms demonstrated a suprasellar mass that, after infusion with contrast medium, showed a peripheral ring-like enhancement consistent with a pituitary adenoma with central necrosis. In patients with symptoms or signs suggesting subarachnoid hemorrhage or meningitis, the finding of an enlarged sella turcica on plain skull roentgenograms should raise the possibility of pituitary apoplexy. This diagnosis may be rapidly and safely confirmed by computerized tomography. (<i>JAMA</i>244:59-61, 1980)