Yasuyuki Kinoshita

Role of PROPELLER diffusion-weighted imaging and apparent diffusion coefficient in the evaluation of pituitary adenomas

OBJECTIVE The relationship between tumor consistency and apparent diffusion coefficient (ADC) values is controversial. We evaluated the role of the ADC using an advanced diffusion-weighted imaging (DWI) technique. We employed periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) DWI acquired on a 3-T magnetic resonance imaging (MRI) scanner to assess the consistency of pituitary adenomas and examined the relationship between the ADC and the hormone secretion status of the tumors and their MIB-1 labeling index (MIB-1 LI). MATERIALS AND METHODS The study protocol was approved by our institutional review board. We retrospectively studied 24 operated patients with pituitary adenomas who had undergone PROPELLER DWI on a 3-T MRI scanner. Conventional MRI findings were expressed as the ratio of the signal intensity (SI) in the lesions to the SI of the normal white matter and the degree of contrast enhancement. Minimum-, mean-, and maximum ADC (ADCmin, ADCmean, ADCmax) values were calculated. The consistency of the tumors was determined by neurosurgeons. All surgical specimens were submitted for histological study to calculate the MIB-1 LI and the percent collagen content. Preoperative MRI-, intraoperative-, and histological findings were analyzed by a statistician. RESULTS Our study included 15 soft-, 5 fibrous-, and 4 hard tumors. Tumor consistency was strongly associated with the percent collagen content. However, neither the tumor consistency nor the percent collagen content was correlated with MRI findings or ADC values. The SI of growth hormone-producing adenomas on T2-WI was lower than of the other pituitary adenomas studied (p<0.01); no other significant difference was found in the ADC or on conventional MRI between pituitary adenomas with different secretory functions. The MIB-1 LI of pituitary adenomas was not correlated with their appearance on conventional MRI or their ADC values. CONCLUSION Using the PROPELLER DWI technique we confirmed that the ADC was not correlated with the consistency of pituitary adenomas. We also demonstrate that the ADC was not associated with the hormone-secreting status or the MIB-1 LI of pituitary adenomas.

Role of PROPELLER diffusion weighted imaging and apparent diffusion coefficient in the diagnosis of sellar and parasellar lesions

OBJECTIVE To evaluate the role of the apparent diffusion coefficient (ADC) using periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion weighted imaging (DWI) in the differentiation between sellar and parasellar mass lesions. MATERIALS AND METHODS The study protocol was approved by our institutional review board. We retrospectively studied 60 patients with sellar and parasellar lesions who had undergone PROPELLER DWI on a 3-T MR imager. Conventional MRI findings were expressed as the ratio of signal intensity (SI) in the lesions to the normal white matter and the degree of contrast enhancement. ADC values were calculated as the minimum (ADC-MIN), mean (ADC-MEAN), and maximum (ADC-MAX). All patients underwent surgery and all specimens were examined histologically. Logistic discriminant analysis was performed by using the SI ratios on T1- and T2-weighted images (T1-WI, T2-WI), the degree of enhancement, and absolute ADC values as independent variables. RESULTS ADC-MIN of hemorrhagic pituitary adenomas was lower than of the other lesions with similar appearance on conventional MRI (non-hemorrhagic pituitary adenomas, craniopharyngiomas, Rathkes cleft cysts; accuracy 100%); the useful cut-off value was 0.700 x 10(-3)mm(2)/s. ADC-MAX of meningiomas was lower than of non-hemorrhagic pituitary adenomas (accuracy 90.3%; p<0.01). ADC-MIN of craniopharyngiomas was lower than of Rathkes cleft cysts (accuracy 100%; p<0.05). CONCLUSION As PROPELLER DWI is less sensitive to susceptibility artifacts than single-shot echoplanar DWI, it is more useful in the examination of sellar and parasellar lesions. Calculation of the ADC values helps to differentiate between various sellar and parasellar lesions.

Postoperative cortical venous infarction in tumours firmly adherent to the cortex

It is sometimes difficult to separate extra-axial tumours from the cortical veins in case of tumours attaching tightly to the cortex and the cortical veins. We present two patients having a postoperative cortical venous infarction. A 59 year old female had convexity meningioma above the motor cortex where abnormal cortical anastomotic veins developed. Transient hemiparesis occurred after total removal of the tumour because of venous infarction and cyst formation resulting from sacrifice of these veins which were tightly adherent to the tumour surface. A 15 year old boy with immature teratoma of the pineal region, showing several draining veins around the vascular-rich tumour, presented transient drowsiness, diplopia and partial impairment of bilateral visual acuity postoperatively because of localised cortical brain and venous damage. It is important to make an effort to preserve main cortical veins during operation as much as possible, even if the tumour adheres to the cortical surface.

Pituitary metastases: current practice in Japan

OBJECT With advancement of cancer treatment and development of neuroimaging techniques, contemporary clinical pictures of pituitary metastases (PMs) must have changed from past reports. The goal of this paper was to elucidate the clinical features of PMs and current clinical practice related to those lesions. In this retrospective study, questionnaires were sent to 87 physicians who had treated PMs in Japan. RESULTS Between 1995 and 2010, 201 patients with PMs were treated by the participating physicians. The diagnosis of PM was histologically verified in 69 patients (34.3%). In the other 132 patients (65.7%), the PM was diagnosed by their physicians based on neuroimaging findings and clinical courses. The most frequent primary tumor was lung (36.8%), followed by breast (22.9%) and kidney (7.0%) cancer. The average interval between diagnosis of primary cancer and detection of PM was 2.8 ± 3.9 (SD) years. Major symptoms at diagnosis were visual disturbance in 30.3%, diabetes insipidus in 27.4%, fatigue in 25.4%, headache in 20.4%, and double vision in 17.4%. Major neuroimaging features were mass lesion in the pituitary stalk (63.3%), constriction of tumor at the diaphragmatic hiatus (44.7%), hypothalamic mass lesion (17.4%), and hyperintensity in the optic tract (11.4%). Surgical treatment was performed in 26.9% of patients, and 74.6% had radiation therapy; 80.0% of patients who underwent radiotherapy had stereotactic radiotherapy. The median survival time was 12.9 months in total. Contributing factors for good prognosis calculated by Cox proportional hazard analysis were younger age, late metastasis to the pituitary gland, smaller PM size, and radiation therapy. The Kaplan-Meier survival was significantly better in patients with breast cancer and renal cell cancer than in those with lung cancer. CONCLUSIONS At the time of this writing, approximately 60% (120/201) of PMs had been treated by stereotactic radiation therapy in Japan. The median survival time was much longer than that reported in past series. To confirm the changes of clinical features and medical practice, a prospective and population-based survey is mandatory.

Impact of subclinical haemorrhage on the pituitary gland in patients with pituitary adenomas

Advanced magnetic resonance imaging (MRI) and optical instruments for surgery frequently demonstrate subclinical haemorrhage in pituitary adenomas; however, the effects of subclinical haemorrhage on pituitary glands remain unclear. We sought to clarify the pituitary function in patients with subclinical pituitary adenoma haemorrhage (SPAH).

De novo distal posterior cerebral artery aneurysm.

BACKGROUND De novo aneurysms in the posterior circulation are very rare. The authors describe a first case of ruptured de novo posterior cerebral artery (PCA) aneurysm in the P3 portion. CASE DESCRIPTION A 52-year-old woman with ruptured de novo P3 aneurysm was treated by early endovascular obliteration using Guglielmi Detachable Coils (GDC). To prevent vasospasm, she received postoperative treatment with a hypertensive hypervolemia dilution and a calcium antagonist. She was discharged without neurologic deficits. CONCLUSIONS Aneuryms arising from peripheral segment of PCA are rare, and delayed surgical clipping has been recommended for these lesions. This is the first report of a de novo P3 ruptured aneurysm treated by endovascular embolization using GDC in the acute stage of subarachnoid hemorrhage. The characteristics of de novo posterior circulation aneurysms and the strategy for the distal PCA aneurysms are discussed.

A craniopharyngioma with spontaneous involution of a gadolinium-enhanced region on magnetic resonance imaging

Background: It has not been reported previously that the solid enhancing portion of a craniopharyngioma has involuted without a change in cyst size. Case Description: We herein report a case of a craniopharyngioma with spontaneous involution of a solid gadolinium (Gd)-enhanced region on magnetic resonance imaging (MRI). A 44-year-old female was referred to our department with a mass on MRI associated with headaches and polyuria. The images showed a suprasellar cystic lesion progressing from the posterior pituitary lobe to the right hypothalamus along the pituitary stalk. Examinations of the cerebrospinal fluid showed aseptic meningitis and a positive titer of beta-human chorionic gonadotropin (HCG-β) preoperatively. The hypothalamic lesion became enlarged over the following 3 weeks, and a biopsy of the posterior pituitary lobe was performed via the endonasal transsphenoidal approach under a preoperative diagnosis of a germ cell tumor (GCT). The histological diagnosis was a craniopharyngioma, and the patients postoperative findings on MRI were atypical: The solid Gd-enhanced region in the hypothalamus had spontaneously decreased in size and the peritumoral edema had improved, although the biopsy site in the posterior pituitary lobe was distant from the area of shrinkage. We speculated that the involutional portion on MRI mimicking a tumor was actually the normal hypothalamus, which was abnormally enhanced due to a disruption of the blood-brain barrier caused by the craniopharyngioma. Conclusion: Gd-enhanced regions of parenchyma neighboring the cysts of craniopharyngioma should be carefully managed, taking into consideration the possibility of the enhancement of normal tissue.

The long-term recurrence of Rathke's cleft cysts as predicted by histology but not by surgical procedure

OBJECTIVE Patients with symptomatic Rathkes cleft cysts (RCCs) managed by surgical treatment often experience recurrence. The authors attempted to clarify the outcome of surgically treated RCCs over a long-term follow-up period. METHODS Ninety-one consecutive RCC patients with a follow-up period of more than 12 months (mean 80.2 months, range 12-297 months) were retrospectively studied. The authors examined the clinical features and postoperative course of patients who experienced a reaccumulation of cyst contents visible on MRI after the initial surgery, and they investigated data from the patients who underwent reoperation for symptomatic recurrent RCCs. RESULTS Reaccumulation of cyst contents occurred in 36 patients (39.6%). In 34 of these patients, a reaccumulation occurred in the first 5 years after surgery. The initial cysts in these patients were most often large, with squamous metaplasia in the cyst walls. Thirteen patients (14.3%) with recurrent symptoms underwent a reoperation, and 10 of the 13 patients had a reaccumulation of RCCs within the 1st year after surgery. The reoperations were performed in the 1st year (61.5%) or several years later (23.1%). Patients were likely to initially have had a visual disturbance and the cyst walls likely included squamous metaplasia. However, no association was observed between the incidence of reaccumulation/reoperation of RCCs and the surgical procedure for RCCs. CONCLUSIONS The reaccumulation rate of RCC is high in the long-term period, and it is associated with the histological findings but not with the surgical procedure. Long-term monitoring, for a period of at least 5 years, should therefore be conducted to identify and assess any RCC reaccumulation.

Review of Current Evidence Regarding Surgery in Elderly Patients with Meningioma

The Japanese population features the highest rate of elderly individuals worldwide. Moreover, Japan has the highest number of computed tomography/magnetic resonance imaging devices in the world, which has led to an increase in the incidental detection of meningioma in healthy elderly patients. Many previous papers have discussed the risks and indications for surgery in this patient population, but available information remains insufficient, and the definition of “elderly” has not been standardized. This review tried to clarify the published evidence and challenges associated with elderly meningioma based on a search of the PubMed database using the terms “meningioma,” “elderly,” and “surgery” for English-language clinical studies and collected related papers published from 2000 to 2016. Twenty-four papers were reviewed and classified by definition of elderly age: over 60, 65, 70, and 80 years old. Six of seven papers that defined the elderly cutoff as over 65 years old were published after 2010, which suggested the consensus definition. Four preoperative grading scoring systems were described and associated with mortality. The 1-year and 5-year mortality rates ranged from 0% to 16.7% and from 7% to 27%, which were comparable with unselected cohorts. Review of risk factor analysis emphasized the importance of considering the preoperative status, presence of comorbidities, and optimum surgical timing during patient selection. Careful choice of patients can also lead to better quality of life. A prospective randomized study considering patient frailty should address the causes and prevention of complications.

Treatable glomerular hyperfiltration in patients with active acromegaly

OBJECTIVE The glomerular filtration rate (GFR) is increased in patients with active acromegaly. The aim of this study is to elucidate whether renal function deteriorates in patients with acromegaly and whether this deterioration is reversible after surgical remission. DESIGN/METHODS A case-control study of 48 acromegalic patients who were surgically cured (cases) and 48 patients with nonfunctioning pituitary adenomas (NFomas, controls) was conducted. We performed clinical and biochemical examinations before surgery and 3months post-surgery. The GFR of each patient was estimated (estimated GFR, eGFR) using their serum creatinine, age, sex, and body surface area, and postoperative changes in the eGFR were assessed. RESULTS The preoperative eGFR was significantly higher in patients with acromegaly than in those with NFoma (99.8 vs 75.1mL/min respectively, P<0.01). In acromegalic patients, surgical remission was accompanied by a significant decline in the eGFR (from 99.8 to 86.2mL/min, P<0.01). Conversely, in patients with NFoma, the postoperative eGFR did not change significantly (from 75.1 to 81.9mL/min, P=0.12). Among the acromegalic patients, the postoperative decreases in the eGFR were more prominent in patients with a preoperatively high or normal vs low eGFR. CONCLUSIONS Our data demonstrated a significant post-surgical eGFR decrease in patients with acromegaly, but not in patients with NFomas. This change in the eGFR was reversible in acromegalic patients with a high/normal preoperative eGFR, but not in those with a low preoperative eGFR. This suggests that the reversible pathophysiological change in some patients is functional but not organic.