Comparison of computed tomography histogram analysis and chemical-shift magnetic resonance imaging for adrenal mass characterization.

BACKGROUND: Computed tomography (CT) histogram analysis and chemical-shift magnetic resonance imaging (MRI) are currently used modalities for adrenal mass characterization. However, it is not yet clear which modality can be regarded as most sensitive in terms of adrenal mass characterization. PURPOSE: To prospectively compare CT histogram analysis and chemical-shift MRI in the characterization of adrenal masses. MATERIAL AND METHODS: Between May 2007 and November 2008, 93 patients (45 males, 48 females; mean age 56.7 years, range 22-85 years) with 109 adrenal masses prospectively underwent both unenhanced CT and chemical-shift MRI examinations. These masses consisted of 67 adenomas and 42 metastases. Histogram analysis was applied with a circular region of interest (ROI) that recorded mean attenuation, total number of pixels, number of negative pixels, and the percentage of negative pixels on unenhanced CT images for each adrenal mass. In the CT histogram analysis, a 10% negative pixel threshold for unenhanced CT was calculated. In chemical-shift MRI, signal intensity drop between in-phase and opposed-phase images was quantitatively calculated so that adrenal-to-spleen chemical-shift ratios and adrenal signal intensity indexes were determined for each of the adrenal masses. A mass was regarded as an adenoma if it contained more than 10% negative pixels by CT histogram analysis, showed an adrenal-to-spleen chemical-shift ratio of less than 0.71, and had an adrenal signal intensity index of more than 16.5% by chemical-shift MRI. The results were compared to reveal which method was most sensitive in the diagnosis of adrenal masses and whether or not a correlation exists between these two modalities. Final diagnoses were based on imaging follow-up of minimum 6 months, biopsy, surgery, and adrenal washout study. RESULTS: On unenhanced CT examinations, all of the 67 adenomas and 21 out of 42 metastases exhibited negative pixels. None of the metastases showed more than 10% negative pixels on CT histogram analysis. An increase in the percentage of negative pixels correlated well with a decrease in the mean CT attenuation. CT histogram analysis using a 10% negative pixel threshold gave a 91% sensitivity and 100% specificity for the diagnosis of an adenoma. On chemical-shift MRI, for an adrenal-to-spleen chemical-shift ratio of less than 0.71, a 97% sensitivity and 100% specificity were achieved, while a 97% sensitivity and 93% specificity were obtained for an adrenal signal intensity index of more than 16.5% for adenoma diagnosis. CONCLUSION: CT histogram analysis method using a 10% negative pixel threshold on unenhanced CT had a good sensitivity and perfect specificity for the differentiation of adrenal adenomas from non-adenomas. In spite of the good results obtained with the CT histogram analysis method, chemical-shift MRI using adrenal-to-spleen chemical-shift ratio and adrenal signal intensity index formulas had a higher sensitivity and could help in the characterization of adrenal masses appearing indeterminate by CT histogram analysis.

Huge retrovesical hydatid cyst with pelvic localization as the primary site: a case report.

We present a patient with symptoms of abdominal pain and frequent urination due to a huge mass in the retrovesical region. All imaging modalities revealed a cystic mass containing small daughter cysts located between the urinary bladder and rectum. Its characteristics led us to suspect the presence of a hydatid cyst, and an indirect hemagglutination test for Echinococcus granulosus was found positive. No other involvement of hydatid cystic disease was detected. The primary site for the hydatid disease was therefore regarded as the pelvis, on which only a few cases have been reported previously. The patient started albendazole therapy, but refused operation. Hydatid cyst should always be considered in the differential diagnosis of abdominopelvic masses in endemic regions of the world.

A novel missense mutation in human TTF-2 (FKHL15) gene associated with congenital hypothyroidism but not athyreosis.

BACKGROUND: Thyroid dysgenesis is the most frequent cause of congenital hypothyroidism (CH), and its genetic basis is largely unknown. Hitherto, two mutations in the human thyroid transcription factor 2 (TTF-2) gene have been described in unrelated cases of CH with cleft palate, spiky hair, variable choanal atresia, and complete thyroid agenesis. Here, we describe a novel TTF-2 mutation in a female child resulting in syndromic CH in the absence of thyroid agenesis. RESULTS: The index case is homozygous for an arginine to cysteine mutation (R102C) of a highly conserved residue within the forkhead, DNA binding domain of TTF-2. Her consanguineous, heterozygous parents are unaffected, and the mutation was not detected in 100 control chromosomes. Consonant with its location, the R102C mutant TTF-2 protein showed loss of DNA binding and was transcriptionally inactive. CH in the proposita was associated with cleft palate, spiky hair, and bilateral choanal atresia. However, radiological studies showed the presence of thyroid tissue in a eutopic location. CONCLUSION: Our findings indicate that human thyroid development can occur despite loss of TTF-2 function and suggest that TTF-2 gene defects should also be considered in cases of syndromic CH without total athyreosis.

Extramedullary plasmacytoma of the maxillary sinus.

Extramedullary plasmacytomas (EMPs) are localized plasma cell neoplasms that occur within the soft tissues; by definition they cannot occur within bone. They account for 1-2% of all plasma cell growths and have a great predilection for the upper respiratory tract, without specific manifestations. Males are more frequently affected during the fifth and sixth decades of life. At initial presentation, multiple myeloma should be excluded. We report herein the case of a 63-year-old man with an EMP arising in the right maxillary sinus who was referred for surgical excision and postoperative radiotherapy and briefly review the clinical implications and management of this pathology.

Primary undifferentiated embryonal sarcoma of the liver misdiagnosed as hydatid cyst in a child: a case report and review of the literature.

Primary undifferentiated embryonal sarcoma (UES) of the liver is a highly malignant mesenchymal origin tumor and has a peak incidence between the ages of 6 and 10 years. We hereby report a case of primary UES of the liver in a 7-year-old male patient who initially was misdiagnosed and treated as hydatid cyst of the liver. The tumor was occupying almost the entire right lobe of the liver and had a mostly cystic appearance with some solid components in it. Because hydatid disease is endemic in this region, it can often lead to misdiagnosis. The correct diagnosis was established after a biopsy and following neo-adjuvant chemotherapy the patient underwent a successful right hepatic lobectomy with complete resection of the tumor. The patient also received adjuvant chemotherapy and is currently disease-free in the present six month period. Primary UES of the liver has a predominantly solid appearance on US in contrast to its mostly cystic appearance on CT and MRI. These paradoxical imaging findings should be kept in mind in order to be able to distinguish this rare tumor from other entities, especially hydatid cyst. Thus, early diagnosis and prompt surgical resection of these tumors together with adjuvant and/or neo-adjuvant chemotherapy can provide complete remission.

Ultrasonographic diagnosis of acute pancreatitis caused by ruptured hydatid disease to the biliary system.

Acute pancreatitis is a rare complication of hydatic disease which occurs following the rupture of a cyst to the intrahepatic bile ducts. Herein, we report a case of a 34-year-old Turkish man, who presented with upper abdominal pain. In laboratory examination, amylase and lipase levels were elevated. Ultrasound examination showed a cystic hypoechoic mass lesion located in the right lobe of the liver with dilated intrahepatic bile ducts, and germinative membranes were detected originating from the ruptured hydatid cyst to the common bile duct. The pancreas was found to be diffusely hypoechoic, consistent with acute pancreatitis. Contrast enhanced CT and MRI were also performed for further evaluation of the primary lesion and its complications.

Precoccygeal epidermal inclusion cyst: ultrasound and MR imaging features.

In this case report, we are presenting a 33 year-old pregnant woman who suffered from pelvic and coccygeal pain. Her medical examination and laboratory tests were found within normal limits. In order to explain her pain, initially a pelvic ultrasound was performed which revealed a huge hypoechoic cystic mass in the precoccygeal-presacral region. She then underwent a pelvic magnetic resonance imaging (MRI) examination in order to better delineate the characteristics and extension of this huge mass. On these images the mass was hypointense on T1 weighted images and extremely hyperintense on T2 weighted images. We also performed a diffusion weighted sequence which exhibited high signal intensity for the mass. We thought that this finding could be suggestive of an epidermal inclusion cyst similar to that of a brain epidermoid cyst which shows bright signal intensity on diffusion weighted images. The patient was operated and the cystic mass removed from the precoccygeal region. Histopathological examination confirmed the diagnosis of epidermal inclusion cyst. This case report suggests that an epidermal inclusion cyst should be considered in the differential diagnosis of intractable pelvic and coccygeal pain. MRI can help to establish the correct diagnosis.

Imaging features of liver hydatid cyst disseminated into pelvis.

Hydatid disease (HD) is a unique parasitic infection that is endemic in many parts of the world. Although the disease primarly affects the liver, HD can be encountered almost anywhere in the body depending on its hematogenous dissemination. In this case report, we describe a 61-year-old man who presented with abdominal pain and urinary complaints. Imaging studies revealed a huge liver and pelvic region lesions that exhibited characteristic imaging findings for type 3 HD.The second lesion was interpreted as occurring due to dissemination from the liver HD. Due to the extensiveness of the disease, both surgery and percutaneous drainage of the lesions were excluded and the patient was put on albendazole treatment.

Cysts of the canal of Nuck: ultrasound and magnetic resonance imaging findings.

Cyst of the canal of Nuck is a rare cause of inguinal swelling in woman. We report a case of a cyst of the canal of Nuck in which sonography showed a tubular cystic structure with internal septae localized within the inguinal canal. Magnetic resonance examination demonstrated that the mass was hypointense on T1-weighted and hyperintense on T2-weighted series and that there were fine hypointense septae inside the mass on the T2-weighted sequence. Diagnosis of cyst of the canal of Nuck was confirmed by surgery and subsequent histopathologic evaluation.

Magnetic resonance imaging of thickened pituitary stalk proceeding to Langerhans cell histiocytosis in a child.

Magnetic resonance imaging has shown isolated pituitary stalk thickening in certain cases of idiopathic or secondary central diabetes insipidus (DI) due to infiltrative processes. We present a 4-year-old boy who was initially diagnosed as having central DI. The MRI showed isolated pituitary stalk thickening with prominent homogeneous contrast enhancement. The remaining findings on MRI were within normal limits. The patient's personal and family history and laboratory and clinical findings were unremarkable; therefore, he was initially diagnosed as having idiopathic DI. Since central DI and isolated pituitary stalk thickening may be considered to be the first manifestations of Langerhans cell histiocytosis, we decided to follow up the patient. After 5 months, following the initial diagnosis, on skeletal X-ray survey, the patient did indeed develop multiple lytic skull lesions which, on biopsy, were histologically typical bone lesions of Langerhans cell histiocytosis.

Rendu-Osler-Weber syndrome presenting with pulmonary arteriovenous fistula.

A pulmonary arteriovenous fistula is an abnormal connection between pulmonary arteries and veins. Patients with Rendu-Osler-Weber syndrome may present with this vascular malformation, which is a typical finding of the disease. Approximately 5-15% of Rendu-Osler-Weber syndrome patients have pulmonary arteriovenous malformations (AVM) and there is usually a family history of AVM in these patients. The malformations are usually located in the lower lobes. In this paper, I describe a 49-year-old male patient with dyspnoea, cough, haemoptysis and epistaxis. Physical examination showed nasal telangiectasias, cyanosis of the lips and nails, and a systolic bruit over the left lung. Chest X-ray revealed a 5-cm mass in the left lower lobe and after magnetic resonance examination, together with 3-D magnetic resonance angiography, it was demonstrated to be a pulmonary arteriovenous fistula. The history of a niece with a similiar history of suspected pulmonary arteriovenous fistula led me to consider the possibility of Rendu-Osler-Weber syndrome presenting with a pulmonary arteriovenous fistula.

Role of magnetic resonance imaging in the early diagnosis of Takayasu arteritis.

Takayasu arteritis is a non-specific inflammatory process of unknown aetiology affecting the aorta and its major branches. It may lead to stenosis or occlusion. We have examined eight patients with clinically diagnosed Takayasu arteritis using contrast-enhanced MRI and also 3-D MR angiography. All patients were female and their ages varied between 22 and 48 years. We were able to show subtle arteritic changes and stenotic lesions in branch vessels in the early phase of the disease by using this imaging modality. Thus, we can state that contrast-enhanced MRI with 3-D MR angiography can be used for the initial diagnosis of Takayasu arteritis. It provides a means to evaluate the vascular tree non-invasively and may replace conventional angiography.

Cardiac disease in the adult: MR evaluation.

Cardiac MR imaging to date has provided detailed information regarding cardiac structure and anatomy. Recent developments in imaging speed have broadened the applications of cardiac MR from the research laboratory to a wide variety of clinical applications involving assessment of both cardiac function and perfusion. In this review, we present methods used for MR evaluation of acquired cardiac disease in the adult. Applications to ischemic heart disease, cardiomyopathy, coronary imaging, myocardial perfusion, and pericardial disease are discussed.