Additional value of hybrid SPECT/CT systems in neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas.

The aim of this review was to evaluate the potential advantages of SPECT/CT hybrid imaging in the management of neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas. From the collected data, the superiority of fused images was observed as providing both functional/molecular and morphological imaging compared to planar imaging. This provided an improvement in diagnostic imaging, with significant advantages as regards: (1) precise locating of the lesions; (2) an improvement in characterization of the findings, resulting higher specificity, improved sensitivity, and overall greater accuracy, (3) additional anatomical information derived from the CT component; (4) CT-based attenuation correction and potential for volumetric dosimetry calculations, and (5) improvement on the impact on patient management (e.g. in better defining treatment plans, in shortening surgical operating times). It can be concluded that SPECT/CT hybrid imaging provides the nuclear medicine physician with a powerful imaging modality in comparison to planar imaging, providing essential information about the location of lesions, and high quality homogeneous images.

Comparison of 111In-[DTPA0]Octreotide Versus Non Carrier Added 177Lu- [DOTA0,Tyr3]-Octreotate Efficacy in Patients With GEP-NET Treated Intra-arterially for Liver Metastases.

AIM: In patients with progressive, metastatic neuroendocrine tumors (NET), intra-arterial radionuclide infusions with high activities of In-[DTPA]-octreotide and more recently with non-carrier added (nca) Lu-[DOTA,Tyr]-octreotate have been performed with encouraging results. However, the affinity profiles (IC50) of these radiopeptides for human sst2 receptors are markedly different (In-[DTPA]-octreotide, 22 ± 3.6 nM and nca Lu-[DOTA,Tyr]-octreotate, 1.5 ± 4.0 nM). The total administered activity is determined by organ dose limits (kidneys and bone marrow), and our aim therefore was to compare and evaluate the therapeutic efficacy of both radiopeptides in metastatic NETs. METHODS: Thirty patients with gastroenteropancreatic (GEP) somatostatin-positive NETs with liver metastases confirmed on biopsy and In-pentetreotide scan were included. They were treated with In-[DTPA]-octreotide (n = 17) or nca Lu-[DOTA,Tyr]-octreotate (n = 13). Blood samples were collected 2, 4, 8, and 24 hours postadministration to calculate residence time in blood and in red marrow. The maximum percentage uptake in organs and tumors was estimated by region of interest analysis, and tumor dosimetry calculations were performed using OLINDA/EXM/ 1.0 software. RESULTS: ncaLu-[DOTA,Tyr3]-octreotate blood radioactivity, expressed as a percentage of the injected dose, was significantly lower than In-[DTPA]-octreotide (P < 0.05), as clearly depicted from the time-activity curves; the background-corrected tumor uptake was significantly higher than In-[DTPA]-octreotide but without any significant difference in other organs (spleen, kidneys, and liver). CONCLUSIONS: Using Lu-[DOTA,Tyr]-octreotate, a 3-fold higher absorbed dose to tumor tissue was achieved compared with In-[DTPA] octreotide. Residence time of nca Lu-[DOTA,Tyr]-octreotate results in a significantly higher absorbed dose to bone marrow compared with In-[DTPA]-octreotide. However, a drawback of In-[DTPA]-octreotide therapy is that the number of administrations would need to be almost doubled to achieve an equal therapeutic outcome as compared with Lu-[DOTA,Tyr]-octreotate.

Magnetic resonance imaging and the severity of dementia in older adults.

Periventricular white-matter lesions were visualized in the brains of elderly patients being assessed for possible Alzheimer's disease. The magnitude of these lesions, expressed as lesion-brain ratios, correlated closely with the severity of dementia indicated by scores on the Blessed Dementia Scale and the Folstein Mini-Mental State Examination. Impairment in several domains of cognitive functioning tested by the Mini-Mental State Examination was also correlated with the relative quantity of periventricular lesions. Correlations were significant with systolic blood pressure, approached significance with age, and were not significant with duration of dementia or the magnitude of the lateral ventricles. These findings indicate the potential utility of structure-function correlations that are possible with magnetic resonance imaging in identifying mechanisms underlying dementia. They suggest that magnetic resonance imaging may be more useful than computed tomography in following the course of dementia.

Papillary thyroid carcinoma (PTC) in Lynch syndrome: Report of two cases and discussion on Lynch syndrome behaviour and genetics.

We present here two cases of papillary thyroid carcinoma (PTC) in patients affected by Lynch syndrome (LS). The first case is a 47-year-old woman with typical hereditary non-polyposis colorectal cancer (HNPCC) syndrome, reported with endometrial and ovarian carcinoma at age 43, and colon cancer at age 45. The patient underwent total thyroidectomy and central node dissection in 2007, at 47years old, with a histological diagnosis of PTC (T1aN1a). Molecular genetics showed a germ-line mutation of the MLH1 gene, 1858 G>T(E620X), with substitution of glycine with a stop codon at position 620. This mutation has pathogenetic significance and was considered responsible for the various tumours of the HNPCC spectrum. In particular, in the same kindred, spanning 5 generations, there were 5 members with colorectal cancer, 4 with endometrial cancer, 3 with gastric and 2 with breast cancer. The second case is a 34-year-old man with typical HNPCC syndrome with colonic resection for colon cancer at age 21. The patient underwent total thyroidectomy with central and lateral node dissection in 2010, at age 34, with a histological diagnosis of PTC with nodal metastases (pT4N1b). Molecular genetic analysis showed a germ-line mutation of the MSH2 gene (thymine insertion at position 907). This mutation had pathogenetic significance and was considered responsible for HNPCC development. Two similar cases have been reported: a 39-year-old woman, and a 44-year-old woman, affected by HNPCC syndrome, with anaplastic thyroid carcinoma and undifferentiated thyroid carcinoma, respectively. We reviewed the Lynch syndrome literature on the history, genetics and expanding tumour spectrum of this condition.

Mild to moderate increase of serum calcitonin levels only in presence of large medullary thyroid cancer deposits.

Many open questions remain to be elucidated about the diagnosis, treatment and prognosis of medullary thyroid cancer (MTC). The most intriguing concerns the outcome of MTC patients after surgery. Great importance is usually given to serum calcitonin (Ct) and carcinoembryonic (CEA) levels. It is commonly believed that the higher are the levels of these tumor markers and their kinetics (double time and velocity of markers levels) the worst is the prognosis. However, this is not the rule, as there are huge MTC metastatic deposits characterized by low serum Ct and CEA levels, and this condition is not closely related to the outcome of the disease during post-surgical follow-up. A series is reported here of patients who have these characteristics, as well as a description of their prognosis and clinical outcome.

Quantitative magnetic resonance imaging and the severity of dementia in Alzheimer's disease.

The T2 component of the magnetic resonance imaging (MRI) signal was measured in 11 brain loci in six elderly patients diagnosed as having probable Alzheimer's disease. T2 values and relative amount of periventricular high-intensity foci were significantly correlated with dementia severity, indicated by the Blessed-Roth Dementia Scale score. Although the mean T2 value for left hemispheric structures was more closely correlated with the dementia score, T2 values did not differ significantly in the right and left hemispheres or in gray and white matter. These findings suggest that more severe dementia in Alzheimer's disease is associated with more water in the brain.

Magnetic-resonance imaging used for determining fat distribution in obesity and diabetes.

Computed-tomography scanning and magnetic-resonance imaging (MRI) have been used to quantify intraabdominal and subcutaneous fat depots. In this study MRI was used to define fat-distribution patterns in 24 obese females with non-insulin-dependent diabetes (NIDDM) and 12 females with simple obesity. Subjects had anthropometric measurements and single-slice abdominal scans performed at the umbilicus. In addition, in 10 of the nondiabetic females, measurements were repeated after 10 wk of a very-low-calorie diet. Nondiabetic females had significantly less intraabdominal fat (P less than 0.01) than did the diabetics but had equivalent subcutaneous fat. There was no significant relationship between waist-to-hip ratio and intraabdominal fat, subcutaneous fat, or their ratio. After a weight loss of 10.6 +/- 3.8 kg there were significant decreases in both intraabdominal and subcutaneous fat (P less than 0.01). Weight loss is associated with decreases in fat in both depots.

Acquired cystic disease of the kidneys. Computed tomography and ultrasonography appraisal in patients on peritoneal and hemodialysis.

Screening chronic hemodialysis patients (CHD) for acquired cystic disease of the kidneys (ACDK) and its complications (hemorrhage and neoplasm) has become accepted management. We evaluated patients on CHD as well as patients on chronic peritoneal dialysis (CPD) for ACDK. The kidneys of 80 chronic dialysis patients were examined by CT and real time sonography. Forty-four were hemodialysis and 36 were peritoneal dialysis patients. ACDK was found in more than 90% of both CHD and CPD patients who had been dialyzed longer than three years. Bilateral renal carcinoma was detected in one hemodialysis patient. Our results show that chronic peritoneal dialysis patients are also at risk for ACDK and its associated complications. A similar natural history for the development of ACDK in both forms of dialysis suggests that the same screening precautions should be instituted for chronic peritoneal dialysis patients.

Giant extra-adrenal pheochromocytoma: magnetic resonance imaging with gadolinium-DTPA enhancement.

A case report of a 35-yr-old male presenting with moderate hypertension and a giant extra-adrenal pheochromocytoma is discussed. The patient was treated by chemotherapy and surgery with regression of the lesion and clinical relief of symptoms. Initial magnetic resonance imaging (MRI) with gadolinium-DTPA enhancement revealed a large complex pelvic mass. Follow-up examination following chemotherapy three months later demonstrated partial regression. The MRI findings and the pattern of gadolinium-DTPA enhancement are discussed.

Magnetic resonance angiography of the neck veins.

Time of flight, reduced matrix (64 x 256) MR angiography of the neck veins was performed in four normal subjects and four patients with neck vein thrombosis, either from indwelling catheters (n = 3) or intravenous drug abuse (n = 1). In each case, satisfactory images were acquired. Typical examination times of 3-6 min were required. MR angiography of neck veins gives a unique display of venous anatomy, including collateral veins and occlusions.

Demonstration of aortic lesions via cine magnetic resonance imaging.

Cine-MRI was used to evaluate eight patients with known thoracic aorta disease. Included in this study were three aortic coarctations, two aortic dissections, an aneurysm, a posttraumatic pseudoaneurysm, and a patent ductus arteriosus. Cine-MRI was found to be valuable in the assessment of the pathologic anatomy and associated flow disturbances in these disorders. In seven cases, the images demonstrated the aortic lesion and aberrant blood flow. Our technique was unable to image the structural lesion in the patient with patent ductus arteriosus, but the abnormal blood flow was shown. Angiographic data were available on three of the cases to confirm the MR findings. The MRI images were obtained in axial, coronal, sagittal, and oblique planes using fast field echo acquisition technique of cine-MRI. We found the additional data or benefits provided by cine-MRI, when compared to cardiac gated spin echo images, to be most advantageous in the cases of aortic coarctation and dissection only.

Magnetic resonance imaging of pediatric spinal dysraphism.

Thirty pediatric patients with spinal dysraphism were studied with magnetic resonance imaging. A variety of dysraphic anomalies were visualized, including syringohydromyelia, tethered cord, widened spinal canal, meningomyelocele, lipomyelomeningocele, lipomeningocele, intraspinal lipoma, congenital dermal sinus tract, and scoliosis. In 29 of 30 cases, MRI diagnostically visualized spinal cord and dysraphic anatomy. A combination of T1-weighted sagittal and axial imaging planes provided the most complete visualization. In specific cases, T2-weighted examinations were useful in demonstrating likely regions of inflammation bordering infected sinus tracts. MRI demonstrates a wide variety of dysraphic spinal anomalies and effectively screens children for occult spinal dysraphism.

Evaluation of suspected musculoskeletal neoplasms using 3D T2-weighted spectral presaturation with inversion recovery.

This study evaluated the use of the Spectral presaturation with inversion recovery (SPIR) technique with T2-weighting in 43 pathologically proven cases of suspected musculoskeletal neoplasm. Both primary and secondary malignant neoplasms as well as benign neoplasms were studied. The MR features exhibited by this technique are discussed. The images were evaluated by two experienced MRI specialists and graded as to utility into one of four categories as compared to conventional T1- and T2-weighted sequences. In the majority of cases this technique was found to be helpful or extremely helpful. The most useful features of this technique were the elimination of chemical shift artifact, the improved ability to evaluate superficial lesions or the extension of lesions into subcutaneous fat, and substantially improved visualization of both bone marrow and bone cortex interfaces. T2-weighted, fat suppressed imaging proved to be a useful new tool for evaluating musculoskeletal neoplasms.

Cardiac MRI cine and color Doppler in valvular disease: correlative imaging.

Cardiac cine field echo MRI and color Doppler were performed in 13 patients with aortic regurgitation (n = 4) or multiple valvular diseases (n = 9). The size, shape, and direction of regurgitation jets correlated well. Color Doppler was better able to follow flow jets in oblique planes. Cine MRI was better able to evaluate patients with marked cardiac dilatation.

Magnetic resonance imaging of a post-traumatic arteriovenous fistula in the lower extremity.

Currently, magnetic resonance (MR) is most useful as a means of providing distinct images of gross abnormalities in major blood vessels. While new advances and further refinements will continue, MR has proven its value as a convenient and effective diagnostic tool for the recognition and delineation of vascular abnormalities, such as acquired arteriovenous fistulae (AVFs). We report a case of a chronic, post-traumatic AVF, in which MR angiography provided excellent anatomic detail and angiographic correlation.

Primary lymphoma of the cervix: MRI findings with gadolinium.

MRI evaluation of primary cervical lymphoma has not been reported. We report such a case of primary cervical lymphoma, a lesion well seen and well delineated from normal tissue by MRI. Although primary lymphoma of the cervix is a rare entity, the disease does exist and can be well demonstrated by MRI. We evaluated the MR appearance of this lesion with both nonenhanced and gadolinium-enhanced imaging.

Halfscan: clinical applications in MR imaging.

A series of phantom experiments was performed to evaluate the effects of half-Fourier scanning, also known as Halfscan, on signal-to-noise and in-plane resolution. Resolution was not demonstrably effected with the available phantoms and signal-to-noise was seen to vary as the square root of time independent of the implementation of Halfscan. Evaluation of the Halfscan technique was made using data from 240 patients. The technique was found to "salvage" examination in an estimated 70% of uncooperative patients where motion artifact or other patient concerns would have precluded clinically useful studies. Halfscan was also combined with other techniques such as increased number of signal acquisitions, prolonged repetition times and three-dimensional Fourier transform technique.

MRI evaluation of AIDS-related encephalopathy: toxoplasmosis vs. lymphoma.

The spectrum of cranial MRI findings was evaluated in 113 patients with the acquired immunodeficiency syndrome, assessing lesion number, size, location, and configuration in association with the autopsy and/or biopsy results. Correlation of cranial MRI and CT was performed in 32 patients. MRI was shown to be superior in sensitivity of lesion detection demonstrating more lesions than CT in 14 studies (44%) and equivalent information in 18 studies (56%). In no case did CT demonstrate lesions not detected on MRI. We conclude that MRI should be the study of choice in evaluating AIDS-related encephalopathy. Multiple lesions that involve both deep gray matter and white matter suggest the possibility of CNS lymphoma. The "target" appearance on MRI is not helpful in distinguishing toxoplasmosis from lymphoma.

Magnetic resonance imaging of nasopharyngeal and paranasal sinus melanoma.

Malignant melanoma of the nasopharynx and paranasal sinuses is relatively rare. We retrospectively reviewed the magnetic resonance appearance of five cases and correlated this with the histopathological appearance. In all cases, the magnetic resonance (MR) images clearly demonstrated the precise anatomic extent of the tumor and were sensitive in assessing intracranial extension and invasion into surrounding structures, including the skull base. Three cases were reviewed for histopathological evidence of melanin, hemosiderin, and acute hemorrhage. One case was reviewed for melanin and hemorrhage only. The findings in this series suggest that melanoma of the nasopharynx and paranasal sinuses have extremely variable amounts of paramagnetic substances, both melanin and products of hemorrhage. T1 shortening appears to be more often a reflection of the paramagnetic effects associated with products of hemorrhage rather than the presence of melanin.

MRI of the skull.

Thirty-four patients with a wide variety of benign and malignant incidental skull findings on routine magnetic resonance (MR) imaging of the brain were reviewed. In most instances detection of the lesions was not difficult. However, recognition of various patterns of skull involvement in different disease processes is important. This is particularly true in differentiating benign from malignant lesions, which may be a critical factor in patient management.