The role of somatostatin receptor scintigraphy in patients with pituitary adenoma or post-surgical recurrent tumours

To assess the role of scintigraphy with 111In-DTPA-D-Phe-octreotide (111In-octreotide) in the diagnosis of pituitary adenomas and in the evaluation of post-surgical recurrent or residual tumours, we performed scintigraphy with 111In-DTPA-D-Phe-octreotide (SRS) in 35 patients: 14 patients with confirmed pituitary tumours and 15 with confirmed recurrent tumours. Clinical, biochemical and histological analyses, conventional images (CT/MRI), and follow-up assessments during a period of 1 year to 4 years were recorded in all patients. In the present study, scintigraphy with 111In-octreotide showed positive uptake in 10 out of 14 patients with confirmed pituitary tumour and in 13 out of 15 patients with confirmed recurrent tumour, with an overall sensitivity of 79%. SRS showed better results in growth hormone (GH)- and prolactin (PRL)-secreting tumours (7/8 patients correctly identified) than in other adenomas (3/9). SRS detected recurrence of adenocorticotrophic hormone (ACTH)-secreting tumours (4/5 patients correctly identified) and non-secreting tumours (5/7 patients correctly identified). 111In-octreotide scintigraphy, in combination with other imaging modalities, is useful in the diagnosis and follow-up of pituitary tumours. It allows scar tissue to be differentiated from tumour recurrence after surgical treatment and ensures better selection of patients who will benefit from medical treatment with somatostatin analogues.     

Dynamic gadolinium-enhanced MR imaging of pituitary adenomas: usefulness of sequential sagittal and coronal plane images

Dynamic magnetic resonance (MR) imaging for pituitary adenomas is usually performed in a coronal direction; however, small lesions between slices, or lesions located at the anterior or posterior aspect of the pituitary gland might be overlooked on MR images in only the coronal direction. The purpose of our study was to evaluate whether consecutive dynamic MR images in the coronal and sagittal planes improve detection of pituitary adenomas. Eighteen patients with pituitary microadenomas and nine with healthy pituitary glands were included in this study. MR images were performed with 1.5 T superconductive units and commercially-available head coils. After a 5 ml gadolinium contrast injection, eight serial dynamic sagittal images were obtained. Within 3 or 6 min, this was followed by a 10-15 ml gadolinium injection and acquisition of eight serial dynamic coronal images. Dynamic MR images and conventional noncontrast- and contrast-enhanced sagittal and coronal T1-weighted images were evaluated independently in a blind fashion by two neuroradiologists regarding the depiction of pituitary microadenomas. The sensitivities of dynamic enhanced MR imaging in the detection of microadenomas were 61.1% in sagittal direction, 72.2% in coronal direction respectively, and were superior to those of conventional noncontrast- and contrast-enhanced T1-weighted imaging (22.2-50%). The sensitivity of a combination of sagittal and coronal dynamic enhanced MR imaging for the detection of microadenomas was 88.9% and was superior to those of conventional noncontrast- and contrast-enhanced T1-weighted imaging combining sagittal and coronal directions (61.1%, 61.1%) (P<0.05, P<0.05, respectively). The specificity and accuracy of dynamic enhanced MR imaging with combination of sagittal and coronal images was 88.9% respectively. Dynamic gadolinium-enhanced MR imaging, especially using both sagittal and coronal planes, was concluded to be useful for the detection of pituitary microadenomas.     

Assessment of endocrine disorders of the hypothalamic-pituitary axis by nuclear medicine techniques

The following article reviews nuclear medicine techniques which can be used for assessment of endocrine disorders of the hypothalamic-pituitary axis. For planar and SPECT imaging somatostatin-receptor- and dopamine-D2-receptor-scintigraphy are the most widely distributed techniques. These nuclear medicine techniques may be indicated in selected cases to answer differential diagnostic problems. They can be helpful to search for presence and localization of receptor positive tissue. Furthermore they can detect metastasis in the rare cases of a pituitary carcinoma. Scintigraphy with Gallium-67 is suitable for further diagnostic evaluation in suspected hypophysitis. Other SPECT radiopharmaca do not have relevant clinical significance. F-18-FDG as PET radiopharmacon is not ideal because obvious pituitary adenomas could not be visualized. Other PET radiopharmaca including C-11-methionine, C-11-tyrosine, F-18-fluoroethylspiperone, C-11-methylspiperone, and C-11-raclopride are available in specialized centers only. Overall indications for nuclear medicine in studies for the assessment of endocrine disorders of the hypothalamic-pituitary-axis are rare. Original studies often report only about a small number of patients. According to the authors' opinion the relevance of nuclear medicine in studies of clinically important endocrinologic fields, e.g. localization of small ACTH-producing pituitary adenomas, tumor localization in ectopic ACTH syndrome, localization of recurrent pituitary tissue, assessment of small incidentalomas, can not be definitely given yet.     

Ectopic pituitary adenoma with empty sella in the setting of MEN-1 syndrome: detection with 68Ga-DOTANOC PET/CT

Patients with multiple endocrine neoplasia type-1 syndromes are known to have neuroendocrine tumors (NETs) involving the pituitary and gastroenteropancreatic region, in addition to the presence of parathyroid abnormalities. In rare instances adenomas in the ectopic pituitary gland have been reported. As pituitary gland and pituitary adenomas are known to express SSTRs, somatostatin receptor scintigraphy can be used for imaging. Somatostatin receptor-based PET/CT imaging using 68Ga-DOTANOC has become a popular noninvasive imaging modality for evaluation of patients with NETs. The application of 68Ga-DOTANOC PET/CT can be extended to multiple endocrine neoplasia type 1 patients, as is evident from this case study.     

Angiography, computed tomography, magnetic resonance imaging and ultrasonography in detection of liver metastases from endocrine gastrointestinal tumours

Twenty-five patients with endocrine tumours (13 with endocrine pancreatic tumours and 12 with carcinoids) were examined with angiography, computed tomography, magnetic resonance imaging and ultrasonography. Seventeen patients had liver metastases and were followed between 3 and 66 months with serial examinations during treatment with chemotherapeutic agents and interferon. The efficiency of the various techniques to detect metastases was investigated. Analysis of changes in tumour size during treatment was made to see if treatment effects could be monitored with radiologic examinations. Ultrasonography was the best non-invasive method for detection of metastases and is recommended as standard method for imaging in this group of patients. Angiography was even better showing extremely small metastases, less than 5 mm, and is recommended in selected cases. With one exception, no significant change in tumour size was noted in spite of clear laboratory and clinical signs of therapy effect indicating that tumour size determination is not useful for therapy monitoring in this type of disease.     

Imaging of giant pituitary adenomas

We present five proven giant pituitary adenomas studied by CT and MRI, and review the clinical and imaging findings. Our aim was to examine the radiologic appearances and to search for criteria useful in distinguishing these tumors from other sellar and suprasellar tumours, mainly craniopharyngioma. The main differences from small adenomas were high prevalence of macrocysts, a more invasive behaviour and a clinical picture dominated by mass effect rather than endocrine disturbance. Factors supporting the diagnosis of pituitary adenoma in a giant intra- and suprasellar mass include: infrasellar extension, absence of calcification and presence of low-signal cysts on T1-weighted images. Received: 13 October 1997 Accepted: 25 February 1998     

Pituitary adenomas and normal pituitary tissue: enhancement patterns on gadopentetate-enhanced MR imaging

A dynamic study of magnetic resonance (MR) imaging was used to obtain successive heavily T1-weighted coronal images (spin-echo [SE] 100/15 [repetition time msec/echo time msec]) of normal pituitary glands and pituitary adenoma immediately after patients were given an intravenous bolus injection of gadopentetate dimeglumine. The images were obtained every minute for 5-8 minutes at 1.5 T. Usual T1-weighted images (SE 600/15) were also obtained before and after the dynamic study was performed. The study group consisted of 18 patients, 10 with normal pituitary glands, and eight with pituitary adenoma. Normal pituitary glands showed maximum enhancement on the first or second image following the administration of gadopentetate dimeglumine, followed by gradual signal reduction through the later images, whereas pituitary adenomas reached a peak of enhancement later and showed slower signal reduction than normal pituitaries. The difference of enhancement patterns between the normal pituitary gland and the pituitary adenoma produced prominent image contrast on the first or second image after administration of gadopentetate dimeglumine, which improved the visualization of one microadenoma and four normal pituitary glands that had been displaced by large adenomas. Dynamic MR imaging is a useful diagnostic procedure not only for detection of microadenomas, but also for visualization of pituitary glands that have been displaced by large pituitary adenomas.     

Pituitary adenomas: value of MR imaging

MR imaging has become the imaging modality of choice for diagnosis of pituitary adenomas. In order to optimize MR evaluation, dedicated pulse sequences must be utilized and knowledge of diagnostic pitfalls and normal variants is mandatory. The MRI features of pituitary adenomas may vary based on their volume, but also on their cell-type. Postoperative MR imaging based on a pre-established schedule is useful to detect residual and/or early recurrent tumor.     

11C-methionine PET for the diagnosis and management of recurrent pituitary adenomas

Purpose The detection of recurrent pituitary adenoma by magnetic resonance imaging (MRI) is rendered uncertain by the tissue remodelling that follows surgery or radiotherapy. We aimed to evaluate the contribution of PET with ¹¹C-methionine (MET-PET) in the detection and management of recurrent pituitary adenoma.Methods Thirty-three patients with pituitary adenoma were evaluated postoperatively by MET-PET, either because of biological evidence of active residual tumour or because of MRI demonstration of non-functional adenoma growth. We studied 24 secreting adenomas and nine non-functional adenomas.Results In 30 patients, MET-PET detected abnormally hypermetabolic tissue. In 14 out of these, MRI did not differentiate between residual tumour and scar formation. In nine of these 14 cases, major therapeutic decisions were undertaken (radiosurgery and surgery). In another group of 16 patients, both MET-PET and MRI detected abnormal tissue. In one case, neither MRI nor MET-PET detected adenomatous tissue. Finally, abnormal tissue was detected in two patients on MRI solely. In these two cases, failure of MET-PET to reveal the adenoma was attributable to concomitant inhibitory therapy. The sensitivity of MET-PET and MRI varied as a function of the tumour type: all non-functional adenomas were localised by both modalities, while MET-PET detected all adrenocorticotropic hormone-secreting adenomas whereas MRI depicted only one of these eight lesions. Fifteen out of 17 patients treated by radiosurgery showed clinical improvement after treatment.Conclusion We suggest that MET-PET is a sensitive technique complementary to MRI for the detection of residual or recurrent pituitary adenomas. It should gain a place in the efficient management of these tumours.     

Radiation Therapy in the Multimodal Treatment Approach of Pituitary Adenoma

BACKGROUND: Pituitary tumors are relatively uncommon, comprising 10-12% of all intracranial tumors. The treatment consisting of surgery, radiotherapy and drug therapy or a combination of these modalities is aimed at the control of tumor cell proliferation and--in endocrine active tumors--the reduction of hormone secretion. However, the slow proliferation characteristics of pituitary tumors necessitate long-term studies for the evaluation of the treatment results. In the last decade there has been continuous improvement in surgical procedures, radiotherapy techniques and drug generation. In this paper, literature will be reviewed to assess the role of modern radiotherapy and radiosurgery in the management of pituitary adenomas. MATERIAL AND METHODS: Nowadays, magnetic resonance imaging for the definition of the target volume and a real three-dimensional (3-D) treatment planning with field conformation and the possibility for non-coplanar irradiation has to be recommended. Most groups irradiate these benign tumors with single doses of 1.8-2.0 Gy up to a total dose of 45 Gy or 50.4 Gy in extensive parasellar adenomas. Adenomas are mostly small, well circumscribed lesions, and have, therefore, attracted the use of stereotactically guided high-precision irradiation techniques which allow extreme focussing and provide steep dose gradients with selective treatment of the target and optimal protection of the surrounding brain tissue. RESULTS: Radiation therapy controls tumor growth in 80-98% of patients with non-secreting adenomas and 67-89% for endocrine active tumors. Reviewing the recent literature including endocrine active and non-secreting adenomas, irradiated postoperatively or in case of recurrence the 5-, 10- and 15-year local control rates amount 92%, 89% and 79%. In cases of microprolactinoma primary therapy consists of dopamine agonists. Irradiation should be preferred in patients with macroprolactinomas, when drug therapy and/or surgery failed or for patients medically unsuitable for surgery. Reduction and control of prolactin secretion can be achieved in 44-70% of patients. After radiotherapy in acromegaly patients somatomedin-C and growth hormone concentrations decrease to normal levels in 70-90%, with a decrease rate of 10-30% per year. Hypercortisolism is controlled in 50-83% of adults and 80% of children with Cushing's disease, generally in less than 9 months. Hypopituitarism is the most common side effect of pituitary irradiation with an incidence of 13-56%. Long-term overall risk for brain necrosis in a total of 1,388 analyzed patients was estimated to be 0.2%. Other side effects are rare too, and do also depend on the damage produced by tumor itself or preceding surgery. They include deterioration of vision in 1.7% of all cases, vascular changes in 6.3%, neuropsychological disorders such as dementia in 0.7% and secondary malignancies in 0.8%, if single doses of 2.0 Gy and total doses of 50 Gy are not exceeded. CONCLUSION: Conventional radiation therapy of pituitary adenoma is highly effective. It is recommended after subtotal resection of primary tumors such as macroadenomas, after gross total resection from endocrine active adenomas with postsurgical hormone secretion and for recurrent tumors. Radiosurgery seems to be a possible treatment alternative in experienced centers, and only in patients with adenomas smaller than 25-30 mm with a minimum distance of 2-3 mm to the chiasm.     

Preoperative localization and radioguided parathyroid surgery.

Clinical or subclinical hyperparathyroidism is one of the most common endocrine disorders. Excessive secretion of parathyroid hormone is most frequently caused by an adenoma of >or=1 parathyroid gland. Unsuccessful surgery with persistent hyperparathyroidism, due to inadequate preoperative or intraoperative localization, may be observed in about 10% of patients. The conventional surgical approach is bilateral neck exploration, whereas minimally invasive parathyroidectomy (MIP) has been made possible by the introduction of (99m)Tc-sestamibi scintigraphy for preoperative localization of parathyroid adenomas. In MIP, the incision is small, dissection is minimal, postoperative pain is less, and hospital stay is shorter. Localization imaging techniques include ultrasonography, CT, MRI, and scintigraphy. Parathyroid scintigraphy with (99m)Tc-sestamibi is based on longer retention of the tracer in parathyroid than in thyroid tissue. Because of the frequent association of parathyroid adenomas with nodular goiter, the optimal imaging combination is (99m)Tc-sestamibi scintigraphy and ultrasonography. Different protocols are used for (99m)Tc-sestamibi parathyroid scintigraphy, depending on the institutional logistics and experience (classical dual-phase scintigraphy, various subtraction techniques in combination with radioiodine or (99m)Tc-pertechnetate). MIP is greatly aided by intraoperative guidance with a gamma-probe, based on in vivo radioactivity counting after injection of (99m)Tc-sestamibi. Different protocols used for gamma-probe-guided MIP are based on different timing and doses of tracer injected. Gamma-probe-guided MIP is a very attractive surgical approach to treat patients with primary hyperparathyroidism due to a solitary parathyroid adenoma. The procedure is technically easy, safe, with a low morbidity rate, and has better cosmetic results and lower overall cost than conventional bilateral neck exploration. Specific guidelines should be followed when selecting patients for gamma-probe-guided MIP.     

MR imaging of cavernous sinus involvement by pituitary adenomas

The ability of high-resolution MR imaging (1.5 T) to detect invasion of the cavernous sinuses by pituitary adenoma was determined through a retrospective review of 74 patients. These patients were divided into three groups: 25 normal subjects, 24 subjects with invasive pituitary adenomas, and 25 subjects with noninvasive pituitary adenomas. A fourth group of 30 patients, who subsequently underwent surgery for pituitary adenoma, was evaluated prospectively by MR for the presence or absence of cavernous sinus invasion. Several features were analyzed: (1) the detectability of the medial and lateral dural margins of the cavernous sinus (2) the size and variation in intensity of compartments within the cavernous sinus (3) the relationship of endocrine function to the surgical and MR appearance of the cavernous sinus and (4) carotid artery displacement or encasement by tumor. The normal cavernous sinuses were usually symmetric, but their sizes varied. The lateral dural margin of the cavernous sinus was always recognized on MR as a linear, discrete, low-intensity area. The medial dural margin (pituitary capsule) was seen on MR in only two of the 25 normal patients. In all 24 patients with cavernous sinus invasion involvement was unilateral and was most common with laterally positioned prolactin or adrenocorticotropic hormone secretory adenomas. Invasion of the cavernous sinus was suspected by MR in only two of the 13 invasive microadenomas and was questionable in three. In 10 of the 11 macroadenomas with surgically proved dural invasion, MR demonstrated an asymmetric increase in size and intensity of the superior and inferior cavernous sinus compartments. Noninvasive macroadenomas compressed and displaced the cavernous sinus bilaterally. The prospective MR evaluation of 30 patients undergoing surgery for pituitary tumor revealed a sensitivity for predicting cavernous sinus invasion of 55%, a specificity of 85.7%, a positive predictive value of 62.5%, and a negative predictive value of 81.8%. No feature permitted certain distinction between invasive and noninvasive microadenomas, as the medial dural wall of the cavernous sinus could not be reliably identified. The most specific sign of cavernous sinus invasion was carotid artery encasement.     

Non-pituitary origin sellar tumours mimicking pituitary macroadenomas

Although the large majority of sellar tumours are pituitary adenomas, several other pituitary and non-pituitary origin tumours arise in the sellar and parasellar regions. Given their location, non-adenomatous lesions frequently mimic pituitary macroadenomas and can pose a diagnostic challenge for the radiologist. Distinguishing rare sellar lesions from the common macroadenoma helps to direct the correct surgical approach and reduce the risk of incomplete resection and/or complications such as cerebrospinal fluid leak with the potential for meningitis. The purpose of this article is to review the imaging features of non-pituitary-origin sellar tumours, focusing on characteristics that may distinguish them from pituitary macroadenomas. Lesions include meningioma, metastatic disease, epidermoid cyst, germinoma, chondrosarcoma, giant cell tumour, and giant aneurysm.     

Adrenal neoplasms

Adenoma, myelolipoma, phaeochromocytoma, metastases, adrenocortical carcinoma, neuroblastoma, and lymphoma account for the majority of adrenal neoplasms that are encountered in clinical practice. A variety of imaging methods are available for evaluating adrenal lesions including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques such as meta-iodobenzylguanidine (MIBG) scintigraphy and positron-emission tomography (PET). Lipid-sensitive imaging techniques such as unenhanced CT and chemical shift MRI enable detection and characterization of lipid-rich adenomas based on an unenhanced CT attenuation of ≤10?HU and signal loss on opposed-phase compared to in-phase T1-weighted images, respectively. In indeterminate cases, an adrenal CT washout study may differentiate adenomas (both lipid-rich and lipid-poor) from other adrenal neoplasms based on an absolute percentage washout of >60% and/or a relative percentage washout of >40%. This is based on the principle that adenomas show rapid contrast washout while most other adrenal neoplasms including malignant tumours show slow contrast washout instead. (18)F-2-fluoro-2-deoxy-d-glucose-PET ((18)FDG-PET) imaging may differentiate benign from malignant adrenal neoplasms by demonstrating high tracer uptake in malignant neoplasms based on the increased glucose utilization and metabolic activity found in most of these malignancies. In this review, the multi-modality imaging appearances of adrenal neoplasms are discussed and illustrated. Key imaging findings that facilitate lesion characterization and differentiation are emphasized. Awareness of these imaging findings is essential for improving diagnostic confidence and for reducing misinterpretation errors.     

Whole-body FDG PET/CT is more accurate than conventional imaging for staging primary breast cancer patients

Purpose

This retrospective study aimed (1) to compare the diagnostic accuracy of whole-body FDG PET/CT for initial breast cancer staging with the accuracy of a conventional, multimodal imaging algorithm, and (2) to assess potential alteration in patient management based on the FDG PET/CT findings.

Methods

Patients with primary breast cancer (106 women, mean age 57?±?13?years) underwent whole-body FDG PET/CT and conventional imaging (X-ray mammography, MR mammography, chest plain radiography, bone scintigraphy and breast, axillary and liver ultrasonography). The diagnostic accuracies of FDG PET/CT and a conventional algorithm were compared. Diagnostic accuracy was assessed in terms of primary tumour detection rate, correct assessment of primary lesion focality, T stage and the detection rates for lymph node and distant metastases. Histopathology, imaging or clinical follow-up served as the standards of reference.

Results

FDG PET/CT was significantly more accurate for detecting axillary lymph node and distant metastases (p?=?0.0125 and p?Conclusion Full-dose, intravenous contrast-enhanced FDG PET/CT was more accurate than conventional imaging for initial breast cancer staging due to the higher detection rate of metastases and synchronous tumours, although the study had several limitations including a retrospective design, a possible selection bias and a relevant false-positive rate for the detection of axillary lymph node metastases. FDG PET/CT resulted in a change of treatment in a substantial proportion of patients.     

Role of 18F-FDG PET–CT imaging for the detection of an unknown primary tumour: preliminary results in 21 patients

Purpose Metastatic cancer of unknown primary origin is a syndrome characterised by a poor prognosis, with a typical survival rate from diagnosis of no longer than 1 year. Only 20–27% of primary tumours are identified by conventional radiological imaging. By contrast, it has been reported that ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) allows the identification of 24–40% of otherwise unrecognised primary tumours. To our knowledge, the studies on this topic have been conducted using ¹⁸F-FDG PET imaging alone. The aim of this study was to evaluate the potential additional diagnostic role of fused ¹⁸F-FDG PET-CT imaging for the detection of metastatic occult primary tumours.Methods The study population consisted of 21 consecutive patients with biopsy-proven metastatic disease and negative conventional diagnostic procedures. Each patient underwent a PET scan, carried out according to a standard procedure (6 h of fasting, i.v. injection of 370 MBq of ¹⁸F-FDG and image acquisition with a dedicated PET-CT scanner for 4 min per bed position).Results ¹⁸F-FDG PET-CT detected the occult primary tumour in 12 patients (57% of cases), providing a detection rate higher than that reported with any other imaging modality, including conventional ¹⁸F-FDG PET.Conclusion The favourable results of this study need to be confirmed in larger patient populations with long-term follow-up.     

MRI动态扫描对垂体微腺瘤的诊断价值

目的:探讨MRI动态扫描对垂体微腺瘤的诊断价值。材料与方法:垂体微腺瘤患者30例均经PHILIP 1.0 NT型MR机行常规矢状面、冠状面T_1WI和T_2WI检查,而后全部又经动态扫描。结果:本组30例的病灶在平扫中,T_1WI呈低信号、T_2WI呈高信号者25例;T_1WI呈等信号、T_2WI呈高信号者3例;T_1WI和T_2WI均呈等信号者1例及高信号者1例。微腺瘤形态征象有垂体柄偏斜(25例)、垂体中央向上膨隆(2例),鞍底下陷(2例),以及瘤内出血(1例),动态扫描后,病灶不增强而正常腺体增强且边界清楚者29例,仅有1例病灶内出血且边界不清楚。结论:MRI动态扫描对垂体微腺瘤的诊断敏感性显著高于平扫,而且它可完整地观察早期正常垂体的增强表现与垂体微腺瘤的增强延迟表现,因而,它有助于对垂体微腺瘤的准确定位,提高诊断准确率。     

Technetium-99m methoxyisobutylisonitrile imaging for parathyroid adenoma: relationship to P-glycoprotein or multidrug resistance-related protein expression

Gland size has been reported to have a major influence on localisation of parathyroid adenomas by technetium-99m methoxyisobutylisonitrile ((99m)Tc-MIBI) imaging. It has also been suggested that P-glycoprotein (Pgp) expression in parathyroid adenomas may influence localisation because false negative studies have been reported with large tumours and true positives with very small tumours. Therefore, the purpose of this study was to retrospectively evaluate the relationship between (99m)Tc-MIBI parathyroid imaging results and Pgp or multidrug resistance-related protein (MRP) expression in parathyroid adenomas. Before surgery, 47 patients with large parathyroid adenomas (larger than 1.5 g) underwent early and delayed parathyroid imaging, 10 min and 2 h after intravenous injection of (99m)Tc-MIBI. Immunohistochemical analyses (IHA) were performed, using multiple non-consecutive sections of the operative specimens, to detect Pgp or MRP expression. According to the results of IHA, the 34 parathyroid adenomas were separated into four groups: (1) three adenomas positive for both Pgp and MRP expression, (2) one adenoma positive for Pgp but negative for MRP expression, (3) four adenomas negative for Pgp but positive for MRP expression and (4) 39 adenomas with negative for both Pgp and MRP expression. All 39 adenomas in group 4 could be detected by (99m)Tc-MIBI parathyroid imaging. None of the eight adenomas in groups 1-3 could be detected by (99m)Tc-MIBI parathyroid imaging ( P<0.05). It is concluded that not only the size of parathyroid adenomas but also significant Pgp or MRP expression limits the sensitivity of (99m)Tc-MIBI imaging in localising parathyroid adenomas preoperatively.     

Clinical usefulness of <Superscript>99m</Superscript>Tc-EDDA/HYNIC-TOC scintigraphy in oncological diagnostics: a preliminary communication

This study assessed the clinical usefulness of a new technetium-99m labelled somatostatin analogue from the standpoint of oncological diagnostics. The study group comprised 40 patients in whom malignant neoplasms (32 primary and 8 metastatic) had been diagnosed. Among the primary tumours there were 21 cases of lung cancer (2 small cell and 19 non-small cell), seven pituitary adenomas (five hormonally active and two inactive), one liposarcoma, two carcinoids and one breast carcinoma. The metastatic tumours consisted of three malignant melanomas, one phaeochromocytoma, one prostatic cancer, one leiomyosarcoma, one pancreatic carcinoma ectopically secreting ACTH and one carcinoid of the thymus. The radiopharmaceutical ^99mTc-EDDA/HYNIC-Tyr³-octreotide was administered i.v. at an activity of 740–925 MBq. The imaging comprised a whole-body scan and a single-photon emission tomography acquisition. Positive scintigrams were obtained in all cases of small cell and non-small cell lung cancer, four out of five hormonally active pituitary adenomas, one out of two cases of carcinoid, the liposarcoma and the breast cancer. Neoplastic metastases were visualised in two out of three patients with melanoma and in patients with phaeochromocytoma, ACTH-secreting pancreatic carcinoma and thymic carcinoid. Scintigrams were negative in both hormonally inactive pituitary adenomas, in one case of metastatic malignant melanoma, in the leiomyosarcoma and in the case of metastasis from prostatic carcinoma. The results of this pilot study indicate that ^99mTc-EDDA/HYNIC-TOC is a potentially useful radiopharmaceutical for imaging of a wide range of primary and metastatic tumours. Special attention should be paid to the successful imaging of all cases of non-small cell lung cancer .     

Nuclear medicine imaging for the assessment of primary and recurrent head and neck carcinoma using routinely available tracers

This article reviews the literature on the use of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) and thallium-201, technetium-99m sestamibi and technetium-99m tetrofosmin single-photon emission tomography (SPET) for the diagnosis and staging of primary and recurrent squamous cell carcinoma of the head and neck (SCCHN). A search of the MEDLINE and CancerLit databases covering articles entered between 1989 and February 2003 was performed. In the case of FDG PET, only full-ring PET studies that included comparison with conventional morphological imaging were considered. Due to the wide variation in methodology, a straightforward meta-analysis of FDG PET literature was impossible. Instead, indicative summary receiver-operating curves of FDG PET and morphological imaging techniques were generated and a paired comparison of the sensitivities and specificities of FDG PET and morphological imaging performed. Compared with conventional morphological imaging, FDG PET proved as sensitive and specific for the detection of primary SCCHN but more sensitive and specific for the detection of cervical lymph node involvement (CLNI) and recurrence of SCCHN. Additional studies addressing the role of FDG PET in screening for distant metastases and synchronous primary tumours are mandatory. Following negative conventional evaluations, FDG PET identifies occult primary tumours in 20–50% of patients presenting with CLNI. As regards the use of ²⁰¹Tl, ^99mTc-sestamibi and ^99mTc-tetrofosmin, more studies are required to define whether these imaging agents could form part of the current diagnostic armamentarium in SCCHN patients. It is concluded that FDG PET either is superior to or offers added value when compared with conventional morphological imaging techniques for the purpose of diagnosis and staging of primary and recurrent SCCHN.