Temporal-lobe epilepsy: comparison of CT and MR imaging

In 50 patients with temporal-lobe epilepsy, CT and MR findings were compared. Axial CT scans were obtained before and after administration of contrast material. Coronal MR imaging was carried out with two spin-echo (SE) sequences with a repetition time of 1600 msec and echo times of 35 or 70 msec (SE 1600/35, SE 1600/70). A focal lesion was detected by CT in 12 cases and by MR in 16 cases. If discrete attenuation or signal abnormalities are also taken into account, CT provided a positive finding in 13 cases and MR imaging in 20 cases. With the exception of a small calcification, all the lesions revealed on the CT scans were also detected on the MR images. Among the examinations assessable for temporal-lobe asymmetry, signs of a unilateral reduction in temporal-lobe size were seen on two of 35 CT scans and on 15 of 38 MR images. In three patients who had temporal-lobe resection, a subsequent comparison was made between CT, MR imaging, and pathology. Histologically proven glial reactions that could not be detected on CT were demonstrated as high-signal-intensity lesions on the SE 1600/70 image. We conclude that MR scanning, with its higher sensitivity, superior image quality, and ability of multiplanar imaging, should be the imaging technique of choice in the diagnosis of temporal-lobe epilepsy.     

Telangiectatic focal nodular hyperplasia: US,CT, and MR imaging findings with histopathologic correlation in 13 cases

PURPOSE: To review the ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging findings in 13 patients with telangiectatic focal nodular hyperplasia (FNH) and to compare imaging features with histopathologic results from resected specimens. MATERIALS AND METHODS: US, helical multiphasic CT, and MR images in 13 patients with pathologically proven telangiectatic FNH were reviewed retrospectively. Two abdominal radiologists evaluated lesions for number, size, heterogeneity, surface characteristics, presence of a central scar, presence of a pseudocapsule, US appearance, attenuation at CT, signal intensity at MR imaging, and presence of associated lesions. Imaging and pathologic findings were compared. RESULTS: Sixty-one lesions (5-140 mm in diameter) were seen at imaging. Lesions were multiple in eight of 13 (62%) patients. Imaging characteristics were heterogeneity in 26 of 61 lesions (43%), well-defined margins in 43 of 61 (70%), lack of a central scar in 56 of 61 (92%), presence of a pseudocapsule in three of 61 (5%), hyperintensity on T1-weighted MR images in 17 of 32 (53%), strong hyperintensity on T2-weighted MR images in 24 of 54 (44%), and persistent enhancement on delayed contrast material-enhanced CT or T1-weighted MR images in 23 of 38 (61%). No specific US pattern was noted. Two patients had additional lesions: One had classic FNH, and the other had a cavernous hemangioma. Hyperintensity on T1-weighted MR images was due to sinusoidal dilatation. Hyperintensity on T2-weighted MR images correlated well with the presence of inflammation. CONCLUSION: Telangiectatic FNH differs from typical FNH at imaging: Atypical FNH features often observed with telangiectatic FNH are lack of a central scar, lesion heterogeneity, hyperintensity on T1-weighted MR images, strong hyperintensity on T2-weighted MR images, and persistent contrast enhancement on delayed contrast-enhanced CT or T1-weighted MR images.     

Cervicofacial actinomycosis: CT and MR imaging findings in seven patients

BACKGROUND AND PURPOSE: Cervicofacial actinomycosis is uncommon, but without proper treatment it causes extensive tissue destruction. Early diagnosis is critical but usually difficult with cultures or imaging. Our aim was to identify characteristic imaging features that facilitated diagnosis in seven patients with cervicofacial actinomycosis. METHODS: We retrospectively reviewed the CT and MR findings in seven patients with pathologically proved actinomycosis. Histologic diagnosis was made by means of surgical excision or biopsy in seven patients. Culturing was performed in two patients. Enhanced CT scans (n=7) and MR images (n=2) were evaluated for the location, margin, infiltrative nature, enhancement pattern, and presence of lymphadenopathy. RESULTS: CT and MR images showed either a well-defined (n=2) or ill-defined (n=5) mass. Involved areas included the nasal cavity (n=2), buccal space (n=1), pyriform sinus (n=1), aryepiglottic fold (n=1), oro- and hypopharynx (n=1) and tongue (n=1). Imaging confirmed the infiltrative nature, showing the tendency of the lesion to invade across tissue planes and boundaries (n=6). Moderate homogeneous contrast enhancement was seen on CT scans in six patients with several small low-attenuating foci (n=2). T1- and T2-weighted MR images showed intermediate signal intensity with moderate contrast enhancement (n=2). Reactive lymphadenopathy was associated in three patients. CONCLUSION: Although cervicofacial actinomycosis occurs infrequently, it should be included in the differential diagnosis when images show a soft-tissue mass with inflammatory changes and an infiltrative nature in the cervicofacial area.     

Focal cortical dysplasias: MR imaging,histopathologic, and clinical correlations in surgically treated patients with epilepsy

BACKGROUND AND PURPOSE: Focal cortical dysplasia (FCD) covers a spectrum of conditions in which the neuropathologic and electroclinic presentations and the surgical outcomes vary. The aim of this study was to identify the MR features of histologic subtypes of FCD that would be useful for differential diagnosis. METHODS: We reviewed the MR data of 49 patients treated surgically for intractable partial epilepsy, who received a histologic diagnosis of FCD not associated with other brain abnormalities except hippocampal sclerosis and who were classified by histologic criteria as having architectural dysplasia (28 patients), cytoarchitectural dysplasia (six patients), or Taylor's FCD (15 patients). RESULTS: From the MR features, it was generally possible to distinguish Taylor's FCD from architectural or cytoarchitectural dysplasias (non-Taylor's FCD). Findings suggesting Taylor's FCD were focal cortical thickening, blurring of the gray-white matter junction, and hyperintensity (on T2-weighted images) of subcortical white matter often tapering toward the ventricle. Focal brain hypoplasia with shrinkage and moderate signal intensity alterations in the white matter core were present in most patients with architectural dysplasia. The lesion was generally extratemporal in Taylor's FCD and temporal in architectural dysplasia. Ipsilateral hippocampal sclerosis was often present in architectural dysplasia (dual abnormality). CONCLUSIONS: In patients with FCD, Taylor's FCD and non-Taylor's FCD can usually be distinguished with MR imaging, although some overlap exists. A provisional MR diagnosis is important for presurgical investigations and surgical planning and may have prognostic implications.     

Preoperative local staging of rectal cancer with endorectal MR imaging: comparison with histopathologic findings

The purpose of this prospective study was to assess the accuracy of endorectal MR imaging in the preoperative local staging of rectal cancers. In 20 cases, we correlated endorectal MR imaging findings with postoperative histopathologic staging according to TNM classification. The accuracy of endorectal MR for determining the T stage of rectal cancer was 85%. The sensitivity and specificity for detecting lymph node metastases were 90.9% and 55.5%, respectively.     

Hepatocellular carcinoma: correlation of MR imaging and histopathologic findings.

Seventy-two histologically proved nodular hepatocellular carcinomas (HCCs) were studied with magnetic resonance (MR) imaging at 1.5 T. Capsules were present in 56 of the 72 tumors. Thirty-seven capsules were depicted on T1-weighted spin-echo MR images, and 16 were depicted on T2-weighted MR images. Visualization was dependent on thickness and structure of the capsules. Of the 72 tumors, 36 had a mosaic pattern. A mosaic pattern was visualized in 12 of the 36 tumors on T1-weighted images and in 27 of the 36 tumors on T2-weighted images. Six tumors were determined to be histologic grade 1, and all were hyperintense on T1-weighted images, regardless of whether intracellular fat deposits were present. Four of the six grade 1 tumors were isointense on T2-weighted images. In contrast, grades 2 and 3 tumors had various signal intensities on T1-weighted images and most were hyperintense on T2-weighted images. Twenty-one of 32 tumors (66%) with focal areas of increased signal intensity on T2-weighted images had intratumoral dilated sinusoids at histologic examination.     

CT and MR imaging findings in adults with cerebellar medulloblastoma: comparison with findings in children.

The goal of this study was to determine if certain imaging features suggest the diagnosis of cerebellar medulloblastoma in adults and to determine how often the classic CT appearance seen in children is present in adults. The study included 28 adult patients with proved cerebellar medulloblastoma. The tumor was located in the cerebellar vermis in 14 patients and in a cerebellar hemisphere in 14 patients. Thirteen patients had unenhanced CT of the brain, all patients had contrast-enhanced CT, and eight patients had unenhanced MR imaging. The imaging features in adults were compared with those in children, as described in the literature. In our adult patients, all tumors were hyperdense compared with gray matter on unenhanced CT and showed a slight to moderate increase in density after injection of contrast medium. Thirteen lesions had well-defined margins, and 15 had poorly defined margins. Low-density areas consistent with cystic and necrotic degeneration were detected in 23 (82%) of the 28 tumors. By comparison, in children, medulloblastoma usually originates in the vermis. As in adults, the mass is hyperdense on unenhanced CT, but enhances markedly and homogeneously after injection of contrast medium. Usually no evidence of cyst formation or necrosis is seen, and the tumor margins are well defined. This classic CT appearance of medulloblastoma in children was identified in only three (11%) of the 28 adult patients. Medulloblastoma has a variable MR appearance in both children and adults. On T2-weighted images, lesions are hypo-, iso-, or hyperintense compared with normal gray matter. The CT findings of medulloblastoma in adults usually differ from those of medulloblastoma in children. The tumor has a variable and nonspecific appearance in adults and should always be considered in the differential diagnosis of a mass in the posterior fossa.     

Kimura disease: CT and MR imaging findings

BACKGROUND AND PURPOSE:KD is a rare chronic inflammatory disorder of unknown etiology. The purpose of this study was to evaluate the CT and MR imaging findings of KD in the head and neck.MATERIALS AND METHODS:We retrospectively reviewed the CT (n = 21) and MR (n = 9) images obtained in 28 patients (24 males and 4 females; mean age, 32 years; age range, 10–62 years) with histologically proved KD in the head and neck.RESULTS:In these 28 patients, CT and MR images demonstrated a total of 52 non-nodal lesions, 1–8 cm in greatest diameter, in the head and neck. The lesions were unilateral in 11 patients and bilateral in 17 patients. Eleven patients had a solitary lesion, and 17 patients had 2–4 lesions. The parotid and/or periparotid area was the most frequent location, with 36 lesions in 23 patients. The margin of the lesions was well-defined in 1 and ill-defined in 51 cases. Compared with the adjacent muscle, the MR signal intensity of all lesions was iso- to slightly hyperintense on T1-weighted images and hyperintense on T2-weighted images. Most of the lesions demonstrated mild or moderate enhancement on postcontrast CT scans and moderate or marked enhancement on postcontrast MR images. MR images also showed tubular signal-intensity voids in 7 of 13 lesions. Associated lymphadenopathy was demonstrated in 23 patients, usually bilaterally.CONCLUSIONS:Multiple ill-defined enhancing masses within and around the parotid gland with associated regional lymphadenopathy are characteristic CT and MR imaging findings of KD in the head and neck.

KD is a rare chronic inflammatory disorder of unknown etiology, characterized by angiolymphoid proliferation with peripheral eosinophilia and elevated serum IgE. The disease has a predilection for the head and neck and typically occurs in young Asian males.^1,2 Although it was first described in the Chinese literature in 1937 under the designation of “eosinophilic hyperplastic lymphogranuloma,” it was not until 1948 that the disease to become widely known as KD when Kimura and Ishikawa³ reported it in the Japanese literature.⁴ KD often produces subcutaneous tumorlike nodules with frequently associated involvement of the major salivary gland and regional lymph nodes.⁵Although the clinical and histopathologic findings of KD have been well described in the literature, only a few reports have dealt with its radiologic findings, and generally as case reports or small case series.^6–15 The purpose of this study was to describe the CT and MR imaging findings of histologically proved KD involving the head and neck in 28 patients. To our knowledge, this is the largest imaging study of patients with KD of the head and neck.     

Nontuberculous mycobacterial pulmonary infection in immunocompetent patients: comparison of thin-section CT and histopathologic findings

PURPOSE: To identify and describe the thin-section computed tomographic (CT) findings of nontuberculous mycobacterial (NTM) pulmonary infection in immunocompetent patients and to compare these findings with histopathologic findings. MATERIALS AND METHODS: Between April 2002 and March 2003, the thin-section chest CT findings in and histopathologic lung tissue specimens from 22 patients who fulfilled the American Thoracic Society diagnostic criteria for NTM pulmonary infection were retrospectively reviewed. The lung lesion patterns (ie, small nodules, branching centrilobular nodules [ie, tree-in-bud pattern], consolidation, cavities, bronchiectasis, and volume loss) seen at CT at the sites of transbronchial lung biopsy (n = 22) or lobectomy (n = 1) were compared with the histopathologic findings. RESULTS: Thirteen of the 22 patients were found to have Mycobacterium abscessus pulmonary infection; seven, to have Mycobacterium avium-intracellulare complex infection; and two, to have Mycobacterium fortuitum infection. Regardless of the specific infective mycobacterial species, bilateral small nodules (in 22 [100%] lung locations), cylindric bronchiectasis (in 20 [91%] locations), and branching centrilobular nodular lesions (in 17 [77%] locations) were the most common CT findings seen at the biopsy sites. All of the transbronchial lung biopsy specimens showed a thickened bronchiolar wall and bronchiolar and peribronchiolar inflammation at histopathologic analysis. Dilated bronchioles were identified in 19 (86%) patients, and epithelioid granulomas with or without caseation were seen in seven (32%). CONCLUSION: Regardless of the specific infective mycobacterial species, the most common thin-section CT findings of NTM pulmonary infection are bilateral small nodules, cylindric bronchiectasis, and branching centrilobular nodules. These findings correspond histopathologically to bronchiolectasis and bronchiolar and peribronchiolar inflammation with or without granuloma formation.     

Elastofibroma dorsi: CT and MR imaging findings

Elastofibroma dorsi is a benign fibroelastic tumor of unknown etiology that arises bilaterally or unilaterally at the lower subscapular level. It can be easily diagnosed on computed tomography or magnetic resonance images and should not be mistaken for a malignant tumor.     

Deep white matter infarction: correlation of MR imaging and histopathologic findings

Focal and confluent areas of periventricular hyperintensity have been reported on magnetic resonance (MR) images in 30% of patients over 60 years of age. In order to better understand the pathologic basis of these lesions, the authors studied 14 formalin-fixed brains with MR imaging. Multiple focal areas of hyperintensity were identified in the periventricular white matter in three of the 14 brains studied (21%). Subsequent gross and microscopic pathologic examination of both hyperintense and normal-intensity areas was performed on 87 tissue sections. The larger lesions were characterized centrally by necrosis, axonal loss, and demyelination and therefore represent true infarcts. Reactive astrocytes oriented along the degenerated axons were identified at distances of up to several centimeters from the central infarct. This is called isomorphic gliosis and is associated with increased intensity on T2-weighted images that increases the apparent size of the central lesion.     

Acute identification of cranial burst fracture: comparison between CT and MR imaging findings

BACKGROUND AND PURPOSE: Scalp swelling associated with cranial burst fracture, a widely diastatic skull fracture of infants associated with dural laceration and acute cerebral extrusion, may be confused with that of a simple subgaleal hematoma. Both conditions can also be associated with hemorrhagic shock. We sought to improve the early evaluation of infants believed to have sustained cranial burst fracture by including MR imaging, since this study clearly delineates the dural-cortical interface, the site of injury. METHODS: Seven infants aged 1 through 11 months who sustained cranial burst fractures, all initially imaged with skull radiography and CT, were studied or treated from 1992 through 1996. MR imaging was obtained after resuscitation and stabilization. RESULTS: Surgery or autopsy confirmed MR findings (dural laceration and extracalvarial cerebral tissue) in all seven infants. CONCLUSION: MR imaging allows early diagnosis of skull fracture associated with acute cerebral extrusion.     

Renal involvement in patients with autoimmune pancreatitis: CT and MR imaging findings

PURPOSE: To retrospectively evaluate computed tomographic (CT) and magnetic resonance (MR) imaging renal findings at clinical presentation, during treatment, and at follow-up in patients with autoimmune pancreatitis (AIP). MATERIALS AND METHODS: This HIPAA-compliant study received institutional review board approval. All patients included had previously consented to the use of their medical records for the purpose of research. Forty-five patients (38 male and seven female patients; mean age, 64 years) with diagnosis of AIP were included. Forty patients underwent CT or MR imaging at clinical presentation; 33 patients (including five without imaging at presentation) underwent follow-up. CT and MR images were reviewed in consensus by two radiologists for the presence of renal involvement. Various features were evaluated. Clinical characteristics at presentation were compared between patients with and patients without renal involvement. RESULTS: Of the 40 patients who underwent imaging at presentation, 14 (35%) had renal involvement (12 with parenchymal involvement and five with extraparenchymal involvement). Renal parenchymal lesions showed decreased enhancement and appeared as small peripheral cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement. Thirteen patients with renal involvement at presentation underwent a follow-up study. Renal lesions in 10 patients regressed (in nine, after steroid treatment) but progressed in three patients without steroid treatment. Renal lesions were found in two other patients during follow-up. No significant difference in the clinical characteristics was found between patients with and patients without renal involvement. CONCLUSION: Renal involvement in patients with AIP is relatively common and predominantly involves the cortex of the kidney. The lesions improve after steroid treatment but can progress without steroid treatment.     

Liver adenomatosis: clinical, histopathologic, and imaging findings in 15 patients

PURPOSE: To report and correlate the clinical, histopathologic, and imaging findings in 15 patients with liver adenomatosis. MATERIALS AND METHODS: Fifteen adult patients had more than 10 hepatic adenomas each and no history of glycogen storage disease or anabolic steroid use. Ten of them underwent bolus-enhanced dynamic computed tomography (CT) with or without magnetic resonance (MR) imaging, ultrasonography, and/or angiography. RESULTS: Clinical abnormalities included abdominal pain in 11 (73%) and hepatomegaly in 10 (67%) patients, and abnormal liver function in 10 (91%) of 11 patients. The number of adenomas in each patient was 10-50 at imaging, but many more lesions were found in the resected specimens. Hemorrhage was commonly found within adenomas at histopathologic analysis, but only four patients had clinical and imaging evidence of substantial hemorrhage. In all patients, the adenomas increased over time, and two patients developed hepatocellular carcinoma. CT and MR features of the adenomas included evidence of hypervascularity (63%), intratumoral fat (50% of patients at CT, 80% at MR), and decreased conspicuity at portal venous and delayed-phase imaging. Fifty percent of patients had congenital or acquired hepatic vascular abnormalities. CONCLUSION: The imaging and histopathologic features of individual adenomatous lesions are similar to those reported in young women who are taking oral contraceptives. However, the lesions in liver adenomatosis are not steroid dependent but rather multiple, progressive, and symptomatic, and they are more likely to lead to impaired liver function, hemorrhage, and perhaps malignant degeneration.     

Hepatocellular carcinoma in cirrhotic patients: prospective comparison of US, CT and MR imaging

Objectives

To prospectively compare the diagnostic performance of ultrasound (US), multidetector computed tomography (MDCT) and contrast-enhanced magnetic resonance imaging (MRI) in cirrhotic patients who were candidates for liver transplantation.

Methods

One hundred and forty consecutive patients with 163 hepatocellular carcinoma (HCC) nodules underwent US, MRI and MDCT. Diagnosis of HCC was based on pathological findings or substantial growth at 12-month follow-up. Four different image datasets were evaluated: US, MDCT, MRI unenhanced and dynamic phases, MRI unenhanced dynamic and hepatobiliary phase. Diagnostic accuracy, sensitivity, specificity, PPV and NPV, with corresponding 95 % confidence intervals, were determined. Statistical analysis was performed for all lesions and for three lesion subgroups (<1 cm, 1-2 cm, >2 cm).

Results

Significantly higher diagnostic accuracy, sensitivity and NPV was achieved on dynamic + hepatobiliary phase MRI compared with US, MDCT and dynamic phase MRI alone. The specificity and PPV of US was significantly lower than that of MDCT, dynamic phase MRI and dynamic + hepatobiliary phase MRI. Similar results were obtained for all sub-group analyses, with particular benefit for the diagnosis of smaller lesions between 1 and 2 cm.

Conclusions

Dynamic + hepatobiliary phase MRI improved detection and characterisation of HCC in cirrhotic patients. The greatest benefit is for diagnosing lesions between 1 and 2 cm.

Key Points

? US, CT and MRI can all identify HCC in cirrhotic patients ? US has good sensitivity but suffers from false-positive findings ? Dynamic CT and MR have similar diagnostic performance for diagnosing HCC ? Dynamic + hepatobiliary phase MRI significantly improves detection and characterisation of HCC ? The greatest benefit is for the diagnosis of lesions between 1 and 2 cm