MRI of ectopic posterior pituitary bright spot with large adenomas: appearances and relationship to transient postoperative diabetes insipidus

Central diabetes insipidus (vasopressin deficiency) after surgery for pituitary tumours: a systematic review and meta-analysis

OBJECTIVE

Central diabetes insipidus or vasopressin deficiency (AVP-D) is the most frequent water balance disorder after transsphenoidal surgery (TSS) with variable prevalence amongst studies. We aimed to determine rates of newly developed transient or permanent AVP-D in patients with pituitary tumours treated with TSS.

DESIGN AND METHODS

We performed systematic review of Medline, Embase, and Cochrane Library between January 1, 2000 and January 31, 2021 for studies reporting on outcomes for pituitary adenoma, craniopharyngioma, and Rathke's cleft cyst (RCC) after TSS and providing definition of post-operative AVP-D. We pooled the results as proportions with 95% confidence intervals (CIs) using Freeman-Tukey transformation random effects meta-analysis.

RESULTS

From 11 694 studies, 51 were included. Rates of transient or permanent AVP-D were: 17% (95% CI, 13-21) and 3% (95% CI, 2-5) in total group, 16% (95% CI, 12-21) and 2% (95% CI, 2-3) in pituitary adenomas, 31% (95% CI, 24-39) and 30% (95% CI, 22-39) in craniopharyngiomas, and 35% (95% CI, 16-57) and 14% (95% CI, 6-23) in RCCs, respectively. Based on diagnostic criteria, rates of transient or permanent AVP-D were: For hypotonic polyuria, 14% (95% CI, 8-22) and 3% (95% CI, 1-4), for hypotonic polyuria and hypernatraemia, 21% (95% CI, 13-29) and 5% (95% CI, 2-11), and for desmopressin administration, 22% (95% CI, 15-29) and 9% (95% CI, 0-30), respectively.

CONCLUSIONS

Following TSS, a small proportion of patients with pituitary adenoma have permanent AVP-D (2%), but prevalence reaches 30% in ones with craniopharyngioma and 14% in those with RCC. Diagnostic criteria for post-operative AVP-D remain variable affecting reported rates of this condition.

Morphological Classification of Pituitary Tumors With Suprasellar Extension

BACKGROUND AND OBJECTIVES

The objective of this study was to study the association among various morphological parameters and surgical outcomes in pituitary macroadenomas with suprasellar extension.

METHODS

MRI studies of 160 patients undergoing endoscopic transsphenoidal resection of pituitary macroadenomas with suprasellar extension were reviewed. In the coronal plane, tumors were classified into Type 1 (dome-shaped, no constriction at the level of diaphragma sellae) and Type 2 (dumbbell-shaped, with constriction at the level of diaphragma sellae). Based on the dome-to-neck ratio (D/Nr), Type 2 tumors were further classified as Type 2A (wide neck; D/Nr >1 and <1.3) and Type 2B (narrow neck; D/Nr ≥1.3). Surgical outcomes and complications were analyzed using a logistic regression model. Overall extent of resection (EOR) and presence of residual sellar-suprasellar tumor was separately assessed in all patients with available postoperative MRI (n = 149).

RESULTS

There were 108 Type 1 tumors and 26 patients each in the Type 2A and Type 2B subgroups. Tumor subtype was significantly associated with tumor size (P < .001), intraoperative cerebrospinal fluid leak (P < .001), EOR (P < .001), postoperative suprasellar residual tumor (P < .001), and postoperative complications, including diabetes insipidus (P = .005) and visual worsening (P = .003). On multivariate analysis, after adjusting for confounders, Type 2B tumors were negatively associated with EOR (odds ratio [OR] 0.22; 95% CI 0.07-0.68; P = .008) and associated with the presence of postoperative suprasellar residual tumor (OR 18.08; 95% CI 5.20-62.89; P < .001), intraoperative cerebrospinal fluid leak (OR 5.33; 95% CI 1.89-14.99; P = .002), and postoperative diabetes insipidus (OR 4.89; 95% CI 1.67-14.35; P < .001).

CONCLUSION

Preoperative tumor classification based on D/Nr is clinically and surgically relevant, and Type 2B macroadenomas are significantly associated with lower rates of gross total resection and higher rates of postoperative complications after endoscopic transsphenoidal resection.

Predictive factors of postoperative diabetes insipidus in 333 patients undergoing transsphenoidal surgery for non-functioning pituitary adenoma

PURPOSE

Diabetes insipidus (DI) following transsphenoidal surgery (TSS) is a common complication. Although postoperative DI often occurs in patients with craniopharyngioma and Rathke's cleft cyst, postoperative DI in patients with non-functioning pituitary adenoma (NFPA) has not been fully examined. We clarified the clinical characteristics and magnetic resonance imaging (MRI) findings predicting postoperative DI in NFPAs.

METHODS

A total of 333 patients undergoing initial TSS for NFPA were included in this retrospective study. Hyperintensity (HI) in the posterior pituitary lobe was evaluated on preoperative T1-weighted MRI. Based on the findings of HI patients were divided into three groups as follows: HI was not detected (Disappearance group), HI located intrasellarly (Intrasellar group), and HI located suprasellarly (Suprasellar group).

RESULTS

The overall rate of DI was 21.9%, including permanent DI in 0.6%. DI occurred at postoperative day 1 (72.6%) or day 2 (19.2%) and improved within 7 days in most cases (87.7%). Univariable and multivariable analyses showed that the predictive factors of DI were a younger age (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.95-0.99, P = 0.0037) and larger tumor diameter (OR 1.04, 95% CI 1.01-1.08, P = 0.0155). The rate of DI was highest in the Disappearance group (43.8%) followed by the Intrasellar group (26.0%). The OR was 2.17 in the Intrasellar group compared with the Suprasellar group (95% CI 1.17-4.02, P = 0.0141).

CONCLUSIONS

Factors predicting DI following TSS for NFPA were a younger age, larger tumor size, and the location of intrasellar HI on preoperative T1-weighted MRI.

Predictive factors for delayed hyponatremia after transsphenoidal surgery in patients with pituitary adenomas

Objective

The aim of this study was to evaluate the incidence and duration of delayed hyponatremia and to assess the factors influencing the development of delayed hyponatremia after transsphenoidal surgery (TSS) in pituitary adenomas.

Methods

We retrospectively analyzed the clinical data of patients with pituitary adenoma who underwent TSS. Univariable and multivariable statistics were carried out to identify factors independently associated with the occurrence of delayed hyponatremia.

Results

Of the 285 patients with pituitary adenoma who underwent microscopic TSS, 44 (15.4%) developed postoperative-delayed hyponatremia and 241 (84.6%) did not. The onset of delayed hyponatremia occurred an average of 5.84 days post-surgery and persisted for an average of 5.36 days. Logistic regression analysis showed the highest risk of delayed hyponatremia in patients with significant change in tumor cavity height (odds ratio (OR), 1.158; 95% CI, 1.062, 1.262; P = 0.001), preoperative hypothalamus-pituitary-thyroid axis hypofunction (OR, 3.112; 95% CI, 1.481, 6.539; P = 0.003), and significant difference in blood sodium levels before and 2 days after TSS (OR, 1.101; 95% CI, 1.005, 1.206; P = 0.039).

Conclusions

Preoperative hypothyroidism, difference in blood sodium levels before and 2 days after TSS, and the change in tumor cavity height after TSS played important roles in predicting postoperative-delayed hyponatremia onset in patients with pituitary adenomas.

Delayed Occurrence of Diabetes Insipidus After Transsphenoidal Surgery with Radiologic Evaluation of the Pituitary Stalk on Magnetic Resonance Imaging

BACKGROUND

Diabetes insipidus (DI) is a major complication of transsphenoidal surgery (TSS). DI usually occurs within a couple of days after TSS. Delayed occurrence of postoperative DI is rarely observed and its developing mechanisms remain unknown.

METHODS

Six patients were identified as having postoperative delayed DI, which was defined as DI that first occurred 2 or more weeks after TSS. They consisted of 1 male and 5 females, and their mean age was 38.3 years (range, 10-76 years). Five patients were histologically diagnosed with Rathke cleft cyst (RCC), and one had RCC coexisting with prolactin-secreting adenoma. Sequential T1-weighted magnetic resonance imaging was evaluated for hyperintensity (HI) in the pituitary stalk and the posterior lobe, indicating the location of antidiuretic hormone.

RESULTS

No patients had any DI before TSS. Delayed DI occurred 2 weeks to 3 months after TSS and persisted for 2 weeks to 5 months. T1-weighted magnetic resonance imaging showed that the HI in the posterior lobe became faint but did not disappear after DI occurrence, and their intensities increased with recovery from DI. In contrast, the HI in the pituitary stalk was found faintly preoperatively and turned clear postoperatively and decreased with recovery from DI. The morphologic patterns were dependent on DI duration.

CONCLUSIONS

In the delayed occurrence of DI, it was suggested that preoperative antidiuretic hormone transport was mildly congested yet not completely blocked when DI manifested postoperatively. Gradual spreading of inflammation to the infundibulum after RCC removal was considered as 1 possible mechanism of this delayed DI development.

Prediction of postoperative diabetes insipidus using morphological hyperintensity patterns in the pituitary stalk on magnetic resonance imaging after transsphenoidal surgery for sellar tumors

PURPOSE

Diabetes insipidus (DI) remains a complication of transsphenoidal surgery (TSS) for sellar and parasellar tumors. Antidiuretic hormone (ADH) appears as hyper intensity (HI) in the pituitary stalk and the posterior lobe of the pituitary gland on T1-weighted magnetic resonance (MR) imaging. Its disappearance from the posterior lobe occurs with DI, indicating a lack of ADH. The appearance of HI in the pituitary stalk indicates disturbances in ADH transport.

METHODS

This retrospective study included 172 patients undergoing TSS for sellar tumors at our institute from 2006 to 2014. Sequential T1-weighted MR images without enhancement were evaluated for HI in the pituitary stalk and the posterior lobe to assess the localization of ADH before and at intervals after TSS. DI was assessed pre- and postoperatively. HI in the pituitary stalk showed the following morphology: (1) ovoid in the distal end of the pituitary stalk (group A), (2) linear in the distal part of the pituitary stalk (group B), (3) linear in the whole pituitary stalk (group C).

RESULTS

Preoperative DI occurred in 6 patients (3.5 %) with no HI observed in the posterior lobe. Postoperative DI was transient in 82 patients (47.7 %), and permanent in 11 (6.4 %). One week after surgery, HI was absent in the posterior lobe in 74 patients (43.0 %), and present in the pituitary stalk in 99 patients (57.6 %); both were significantly correlated with postoperative DI (p < 0.001). The absence of HI in the posterior lobe (A, 48.9 %; B, 68.3 %; C, 92.3 %), persistence of DI (A, 3.7 days; B, 45.9 days; C, 20.5 months), and duration until HI recovery in the posterior lobe (A, 3.6 months; B, 6.8 months; C, 22.9 months) were greatest in group C, followed by group B, and then group A. Fourteen group A patients did not have postoperative DI despite having HI in the pituitary stalk and the posterior lobe. Four group C patients developed permanent DI with persistence HI in the pituitary stalk.

CONCLUSION

HI in the pituitary stalk and its absence in the posterior lobe indicated postoperative DI, which was transient if HI was detected in the pituitary stalk. DI duration could be predicted by the length of HI in the pituitary stalk, which corresponded to the degree of ADH transport obstruction.

3D dynamic pituitary MR imaging with CAIPIRINHA: initial experience and comparison with 2D dynamic MR imaging

OBJECTIVES

To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk.

METHODS

Participants comprised 32 patients who underwent dynamic pituitary MR imaging due to pituitary or parasellar lesions. 3D dynamic MR with CAIPIRINHA was performed at 3T with 20-s-interval, precontrast, 1st to 5th dynamic images. Normalized values and enhanced ratios (dynamic postcontrast image values divided by precontrast ones) were compared between 3D and 2D dynamic MR imaging for patients with visual identification of posterior lobe and stalk.

RESULTS

In 3D, stalk was identified in 29 patients and unidentified in 3, and posterior lobe was identified in 28 and unidentified in 4. In 2D, stalk was identified in 26 patients and unidentified in 6 patients, and posterior lobe was identified in 15 and unidentified in 17. Normalized values of pituitary posterior lobe and stalk were higher in 3D than 2D (P<0.001). No significant difference in enhancement ratio was seen between 3D and 2D.

CONCLUSIONS

3D dynamic pituitary MR provided better identification and higher normalized values of pituitary posterior lobe and stalk than 2D.

Postoperative imaging of the pituitary gland

Imaging often plays an important role in the management of patients who have been surgically treated for pituitary disease. The primary goals of the radiologist are to recognize normal postoperative findings, to distinguish iatrogenic changes in the sella and surrounding regions from residual tumor, and to detect surgical or therapy-related complications when apparent on imaging. Accurate assessment of the postoperative pituitary region requires an understanding of the normal sellar anatomy and of the common neurosurgical techniques applied to this region and familiarity with the appearance of this region in both the acute postoperative setting and also upon subsequent subacute and later examinations.

Imaging of sellar and parasellar lesions

The sellar and parasellar region is an anatomically complex area where a number of neoplastic, infectious, inflammatory, developmental and vascular pathologies can occur. Differentiation among various etiologies may not always be easy, since many of these lesions may mimic the clinical, endocrinologic and radiologic presentations of pituitary adenomas. The diagnosis of sellar lesions involves a multidisciplinary effort, and detailed endocrinologic, ophthalmologic and neurologic testing are essential. CT and, mainly, MRI are the imaging modalities to study and characterise normal anatomy and the majority of pathologic processes in this region. We here provide an overview of the most relevant MRI and CT characteristics together with clinical findings of pituitary tumors, vascular, inflammatory and infectious lesions found in the sellar/parasellar region in order to propose an appropriate differential diagnosis.

Clinical characteristics, etiologies and pathophysiology of patients with severe short stature with severe GH deficiency: questionnaire study on the data registered with the foundation for growth science, Japan

In this study, we sent questionnaires to doctors treating severe short stature with severe GH deficiency (GHD) (height SDS (HtSDS) below -4 and all peak GH to provocative stimuli below 2 micro/L) (abbreviated as Severe Case), and obtained effective replies of 51 cases. The clinical characteristics, etiologies, and pathophysiology of these patients were examined. Among the 51 Severe Cases no consanguinity was observed, 44 were IGHD (24 males and 20 females), 3 were GH-1 gene deletion, 2 were Pit-1 gene mutation, and 2 were achondroplasia. HtSDS in these Severe Cases was already remarkably low at 12 (-3.0) and 24 months old (-3.9), while their birth weight and birth length were within normal ranges. Among 44 patients with IGHD, 12 were isolated GHD, and the remaining 32 were combined pituitary hormone deficiency (CPHD). Pituitary MRI was undergone in 25 idiopathic GHD, and abnormal findings (pituitary atrophy, interruption of stalk, and ectopic posterior lobe) were observed in 21 patients with CPHD. More than half of these patients had the history of breech delivery. Three patients with GH-1 gene mutation showed normal pituitary MRI, whereas one of two patients with Pit-1 mutation showed pituitary atrophy and narrowing of pituitary stalk. In conclusion, Severe Cases tended to have CPHD, and the incidence of Severe Case was only 0.6% of total IGHD. Although GHD due to genetic disorders is considered to be extremely rare (0.06% of total IGHD), the incidence reaches high levels (9.8%) among Severe Cases. Growth disorders in these Severe Cases seem to occur soon after delivery. Much earlier diagnosis and hGH treatment are desirable to attain better final height in the Severe Cases. GH-1 and Pit-1 gene analyses are crucial, when genetic abnormalities other than achondroplasia are suspected.

DDAVP use in patients undergoing transsphenoidal surgery for pituitary adenomas

BACKGROUND

Disorders of fluid and sodium regulation, often termed "diabetes insipidus," are a frequent occurrence following surgery for pituitary adenomas. The present study was undertaken to identify the incidence of diabetes insipidus after pituitary surgery and its associated factors.

METHODS

A retrospective review of the medical records 300 patients who underwent transsphenoidal surgery for pituitary adenoma was undertaken. Information regarding patient gender, perioperative serum sodium levels and urinary output volumes, tumor size, previous pituitary surgery, tumor subtype, and the use of DDAVP was gathered. A multivariate statistical analysis was performed.

FINDINGS

Follow-up data were available on 288 patients. During the inpatient postoperative hospital stay, DDAVP was administered to 19% of all patients and 16% of patients not taking DDAVP preoperatively. Of patients with normal fluid/sodium regulation preoperatively, DDAVP was prescribed for 9% at discharge and 4% at 6 weeks postoperatively. Only 1.4% of patients were taking vasopressing replacement at the time of last follow-up. Significant correlations were found between gender, previous surgery, serum sodium levels, and urine volumes at various time points. Immunohistochemical type of tumor and tumor size were not related to DDAVP requirement.

CONCLUSIONS

Transient hypotonic polyuria is frequently encountered after pituitary surgery. However, only a small number of patients will develop a long-term requiring for ongoing medical treatment. Previous surgery, female gender, and elevated serum sodium and urine volumes in perioperative period were associated with DDAVP requirement.

Ectopic posterior pituitary high signal in preoperative and postoperative macroadenomas: dynamic MR imaging

BACKGROUND AND PURPOSE

In patients with macroadenoma, posterior pituitary high signal (PPHS) on T1-weighted magnetic resonance (MR) imaging is sometimes observed in an ectopic location. The present study compared incidences of ectopic PPHS before and after macroadenoma surgery using MR imaging, including dynamic MR imaging to ascertain whether this ectopic change is irreversible.

MATERIALS AND METHODS

MR imaging was performed preoperatively in 111 cases of macroadenoma, and then repeated more than 1-year postoperatively in 47 patients. Enhancement of PPHS was assessed using dynamic MR imaging. Areas of enhanced hyperintensity were considered true PPHS, and the relationship between presence and location of true PPHS and adenoma volume was analyzed. Moreover, changes in the presence and location of true PPHS were ascertained among the patients who underwent postoperative follow-up MR imaging.

RESULTS

Preoperatively, PPHS was seen only in the normal location in 29 patients (Group A: 26.1%). High signal was detected only in an ectopic location in 58 patients, and early enhancement of this ectopic high signal was confirmed by dynamic MR imaging in 56 patients (Group B: 50.5%). No PPHS was observed in 24 patients (Group C: 21.6%). Adenoma volume was significantly greater for Group B than for Group A (p<0.001). Among the Group B patients who underwent MR imaging postoperatively (n=31), the location of PPHS was not changed, except for two patients in whom PPHS was absent. Postoperatively, PPHS was not observed in the normal location in any patient in the Group B.

CONCLUSIONS

Greater volume of adenoma is associated with a higher incidence of ectopic PPHS, and the ectopic change is irreversible.