MR Imaging Findings of the Pituitary Gland in Patients with Transfusional Hemochromatosis: Two Case Reports

Hemochromatosis is a disorder caused by excessive iron deposition in parenchymal cells that leads to cellular damage and organ dysfunction. The excessive iron overload of secondary hemochromatosis is associated with chronic disorders of erythropoiesis that are treated with prolonged repeated blood transfusions. We experienced two cases of transfusional hemochromatosis involving the pituitary gland, and we report the findings of the MR imaging.

MR Differentiation of Craniopharyngioma from Pituitary Macroadenoma

PURPOSE: We wanted to determine the differential points between craniopharyngioma and pituitary macroadenoma on MRI. MATERIALS AND METHODS: The MRI findings in twenty seven patients (age range: 14-67 years, mean age: 46 years, 17 males and 10 females) with pathologically proven craniopharyngioma and twenty four patients (age range: 23-64 years, mean age: 54 years, 8 males and 16 females) with pathologically proven pituitary macroadenoma were analyzed retrospectively by two radiologists. We analyzed the location, the contour of the mass, the presence of high signal intensity on the T1 weighted images, the thickness of the enhancing wall, separation between the mass and the pituitary gland, and the presence of attachment or compression to the midbrain. RESULTS: On MRI, craniopharyngiomas showed a suprasellar location, high signal intensity on the T1 weighted images and a larger suprasellar portion. After contrast enhancement, the separation of the mass from the pituitary gland is more distinct than that of the pituitary macroadenomas. The craniopharyngiomas showed the presence of attachment or compression to the midbrain. The pituitary macroadenomas had a larger intra- or infrasellar portion than that of the craniopharyngiomas, and they also showed a thicker enhancing wall after contrast enhancement. CONCLUSION: The location, contour of the mass, presence of high signal intensity on T1 weighted images, thickness of the enhancing wall, separation of the mass from the pituitary gland and the presence of attachment or compression to midbrain are useful differential points between craniophayngioma and pituitary macroadenoma on MRI.

Pituitary Adenoma with Extensive Calcifications Mimicking Craniopharyngioma: A Case Report

A 27 year old man presented with complaints of headache and visual disturbance, first noted six months earlier. Simple radiographs of skull sellar widening and calcification. Brain CT revealed a 3 X3 X4 cm-sized sellar suprasellar mass with heavy calcification. T1-weighted MR images showed that the signal intensity of the mass was slightly lower than that of the gray matter, while T2-weighted images showed heterogeneous high signal intensity with central low-signal-intensity foci, suggesting calcification After contrast infusion, enhancement was irregular. Surgery revealed a 4 X5 cm sized, well-demarcated, lobulated mass adhering to the meninges. Papillary-type pituitary adenoma was histologically confirmed. We report the CT and MR findings of atypical pituitary adenoma with extensive internal calcification mimicking craniopharyngioma.

Colloid Cyst in Pituitary Gland: A Case Report

Colloid cyst is a congenital lesion which is thought to be derived from the primitive neuroepithelium, and is most frequently located in the anterior half of the third ventricle. Colloid cysts rarely occur in the pituitary gland, and we describe a case of pituitary colloid cyst, including the CT, MRI and pathologic findings.

MRI Finding of Reversible Pituitary Hyperplasia Due to Hypothyroidism: A Case Report

We report a case of reversible pituitary enlargement due to hypothyroidism in a 3-year-old male. OnT1-weighted images, the mass was located in the anterior lobe of the pituitary gland, and the signal intensity ofthe mass was equal to that of brain cortex. Gd-DTPA enhanced T1-weighted images showed homogeneous enhancement ofthe mass. After supplemental therapy with thyroid hormone for 8 months, MRI showed that the pituitary gland wasmarkedly smaller.

MRI Finding of Reversible Pituitary Hyperplasia Due to Hypothyroidism: A Case Report

We report a case of reversible pituitary enlargement due to hypothyroidism in a 3-year-old male. OnT1-weighted images, the mass was located in the anterior lobe of the pituitary gland, and the signal intensity ofthe mass was equal to that of brain cortex. Gd-DTPA enhanced T1-weighted images showed homogeneous enhancement ofthe mass. After supplemental therapy with thyroid hormone for 8 months, MRI showed that the pituitary gland wasmarkedly smaller.

Diagnosis of Pituitary Microadenoma: Significance of T2-Weighted MR Image

PURPOSE: To evaluate the significance of T2-weighted MR imaging(T2WI) in the diagnosis of pituitarymicroadenoma. MATERIAL AND METHODS: We retrospectively evaluated the MR imaging findings of 30 cases of pituitarymicroadenoma. Diagnosis was made on the basis of surgery, serum hormonal level, and the presence of mass lesion onMR (T1WI and T2WI), and conventional as well as dynamic contrast enhanced T1WI images were obtained. In each MRsequence, signal intensity and detectability of the tumor were evaluated. We also determined whether diagnosis waspossible on both T1WI and T2WI. In eight cases, histopathologic findings (cellularity, fibrosis, and cysticchange) were correlated with T2 signal intensity of the tumor. RESULTS: T2WI, T1WI, and dynamic and conventionalenhanced T1WI detected the tumor in 21 cases (70%), 21 cases (70%), 28 cases (93.3%), and 22 cases (73.3%),respectively. On T2WI, pituitary microadenomas showed a high signal in 18 cases (60%), an iso-signal in nine(30%), and a low signal in three (10%) compared with normal pituitary gland. In 20 cases (66.7%), diagnosis ofpituitary microadenoma was possible on both T1WI and T2WI, but in one case, the tumor was detected only on T2WI.Three cases with fibrosis, as seen on histopathologic examination showed an iso or low signal on T2WI. CONCLUSION: T2WI is useful in the diagnosis of pituitary microadenoma Decreased signal intensity on T2WI may suggestfibrosis.

Pituitary Adenoma after the Gamma-Knife Radiosugery: correlation of MRI findings with clinical manifestation

PURPOSE: To evaluate changes in the MRI findings of pituitary adenoma after gamma-knife radiosurgery, and tocorrelate these with the clinical outcome. MATERIALS AND METHODS: We evaluated the MRI findings of 27 patientswith pituitary adenoma before and after gamma-knife radiosurgery. Their ages ranged from 16 to 69 years(M:F =8:19), and there were seven cases of microadenoma and 20 of macroadenoma. In 11 cases, the tumor was partiallyremoved before radiosurgery. The follow-up period ranged from three to 43 months. RESULTS: In two cases ofmicroadenoma, complete regression was seen after three and 12 months, respectively, with normalization of hormonelevels and the improvement of symptoms. Among the remaining cases, in which no volume change was noted, hormonelevels normalized in four. Among 20 cases of macroadenoma, volume reduction was seen in 18 patients and completeregression, in two. In cases in which the volume was reduced by 20%, the mean follow-up period was 6.6 months, andin cases in which this was 50%, the period was 15.3 months. On postenhanced T1W images, the most frequent patternswere rim enhancement (n=10;50%) and homogneous enhancement changed to rim enhancement (n=4;20%). In six of ninecases(66.7%) of hyperfunctioning macroadenomas, hormone levels normalized, and in nine of 11 cases (81.8%) ofnonfunctioning macroadenomas, symptom improvement was noted. In six of 20 cases in which the enhancement patternchanged after gamma knife radiosurgery, there was clinical improvement. Among 14 cases in which there was nochange in the enhancement pattern, nine showed clinical improvement but five did not. The former showed a meanvolume reduction of 62.5% and the latter, 16.5%. CONCLUSIONS: After gamma-knife radiosurgery, clinicalimprovement in microadenomas can be expected, regardless of volume change. The volume of macroadenomas decreasedand a rim enhancement pattern was observed after gamma-knife radiosurgery. A marked reduction in the volume of atumor, or a change in its enhancement pattern may indicate clinical improvement.

MR Imaging of Pituitary Abscess: Report of Two Cases

Pituitary abscess is a rare condition of the pituitary gland. We report MR imaging findings in two cases of surgically-confirmed pituitary abscess occurring in women aged 39 and 28. In both a peripheral rim enhancing lesion, similar to abscesses in other areas of brain, was seen in the pituitary fossa.

MRI Findings of Rathke Cleft Cyst

PURPOSE: To describe the characteristic MRI findings of the Rathke cleft cyst. MATERIALS AND METHODS: During a seven-year period, we retrospectively evaluated the MRI findings of 24 pathologically-proven Rathke cleft cysts. The patients included ten men and 14 women, And their mean age was 37. MRI findings were analyzed in terms of location, shape, size, signal intensity, homogeneity of cyst content, pattern of contrast enhancement, displacement of the pituitary stalk, and mass effect of the cyst on adjacent structures. RESULTS: The location of 14 cases (58%) was sellar or suprasellar; nine (37%) were intrasellar. The mean size of the cysts was 16 x 12mm, as seen on sagittal or coronal images. The characteristic shape of the cyst was a sagging water bag in 13 cases (54%) and upward tenting in eleven (46%). The signal intensity of the cyst varied ; on T1-and T2WI, eleven cases (46%) showed high signal intensity relative to brain parenchyma ; five (21%) showed iso signal intensity on T1WI and high signal intensity on T2WI. While 18 (75%) showed inhomogeneous signal intensity on T1- and T2WI;13 (54%) showed a smudge pattern within the cysts, and six (25%) showed homogeneous signal intensity on T1 and T2WI. On Gd-DTPA enhanced images, thin-rim enhancement surrounding the cyst was seen in 20 cases (83%). While no enhancement was seen within the cyst. Seventeen cases (71%) showed anterior displacement of the pituitary stalk; two showed posterior displacement and five were indeterminate. Mass effect included compression of the optic chiasm (11cases) and bony erosion or tilting of the sellar floor (8 cases). CONCLUSION: MRI findings of midline intrasellar cyst with a sagging water bag appearance, high signal intensity on T1- and T2WI, inhomogeneity of cyst content, and peripheral rim enhancement surrounding the cyst are common, and are characteristic of the Rathke cleft cyst.

Growth Hormone-Secreting Pituitary Adenoma: Clinical and MR Imaging Findings

PURPOSE: To describe clinical and MRI findings of growth hormone-secreting pituitary adenoma, to determine ifthere are any characteristic MRI findings different from those of other pituitary adenomas, to evaluate the relationship between tumor size and serum growth hormone level, and to assess the results of immunohistochemical study. MATERIALS AND METHODS: We retrospectively analysed clinical and MRI findings of 29 patients with growth hormone-secreting pituitary adenoma confirmed by serum growth hormone level and surgery. We also evaluated the relationship between the tumor volume and serum growth hormone level, and the results of immunohistochemical study. Coronal and sagittal T1-weighted MR images in all patients and gadolinium enhanced T1-weighted MR images in28 patients were obtained with 2.0 T(24 cases) and 0.5 T(5 cases) MR imagers. The images were analyzed in terms oftumor size, signal intensity, degree of contrast enhancement, extent of tumor growth and the presence or absenceof cystic change, hemorrhage and calcification. RESULTS: Clinical manifestations included facial feature changeand soft tissue swelling of hands and feet(n=29), headache(n=12), impaired visual acuity(n=9), symptoms of hyperprolactinemia(n=8), visual field defect(n=5), and others(n=6). On MR images, all of the 29 cases were seen tobe macroadenomas and the size of the tumors averaged 2.2cm(1-5.2 cm). Supra- and infrasellar extensions were seenin 21 and 22 patients, respectively. Cavernous sinus invasion was noted in seven, and in one this was bilateral.Signal intensity was isointense with cortical grey matter in 26 cases(90%). Cystic change or necrosis was seen ineight cases(28%), hemorrhage in four(14%), and calcification in two(7%). After enhancement, most(25/28) of the tumors enhaned less than mormal pituitary in degree. There was no correlation between serum growth hormone level and tumor size. Immunohistochemical study showed positive growth hormone-secreting cells in only 69%(11/16). CONCLUSION: Clinical findings in patients with growth hormone-secreting pituitary adenomas were various and included acromegaly, headache, visual impairment, and symptoms of hyperprolactinemia, for example. On T1-weightedMR images, all tumor were macroadenoma, and there were no characteristic findings different from those of other pituitary tumors. The volume of a tumor did not correlate with serum hormone level. Immunohistochemical study showed positive growth hormone-secreting cells in a limited number of cases.

Usefulness of Dynamic Magnetic Resonance Imaging in Pituitary Microadenomas

PURPOSE: To investigate the usefulness of dynamic MR imaging in the diagnosis of pituitary microadenomas. MATERIALS AND METHODS: Dynamic MR imaging was performed in 31 patients with suspicious pituitary microadenoma. The MR examination was performed on a 2.0T or 1.5T superconductive MR unit using spin echo(SE) technique with arepetition time of 200m sec, echo time of 15 m sec, 128 x 256 matrix and one excitation. Actual sampling time perimage was 26 seconds. The field of view was 25cm and a section thickness of 3mm with 2mm gap was chosen. After arapid hand injection(2-3ml/sec) of Gd-DTPA(0.1 mmol/kg of body weight), dynamic coronal plane MR images were obtained every 20-30 seconds for 3-5 minutes. Between never and ten serial images were usually obtained. After dynamic MR imaging, routine SE T1-weighted images(T1WI) were obtained in the same plane as dynamic images, and detection rates of pituitary microadenoma using dynamic MR imaging and using routine enhanced T1WI, were retrospectively compared. RESULTS: On early dynamic images(30|90 seconds), 23 of 31 adenomas(74.2%) were well visualized, with a clear border ; of particular note is the fact that 11 of the 31 were well visualized at 30-second dynamic image. On late dynamic images(120-180 seconds), six microadeomas(19.4%) were well-visualized and; two(6.5%) were well-visualized throughout on all dynamic images. Meanwhile, 12 of 31 microadenomas(38.7%) were well-visualized on routine Gd-DTPA enhanced T1WI. CONCLUSION: Dynamic MR imaging with Gd-DTPA bolus injection was the most useful technique for the detection of pituitary microadenomas, especially on early-phase dynamic images.