Cerebral Ketones Detected by 3T MR Spectroscopy in Patients with High-Grade Glioma on an Atkins-Based Diet.

BACKGROUND AND PURPOSE: Ketogenic diets are being explored as a possible treatment for several neurological diseases, but the physiologic impact on the brain is unknown. The objective of this study was to evaluate the feasibility of 3T MR spectroscopy to monitor brain ketone levels in patients with high-grade gliomas who were on a ketogenic diet (a modified Atkins diet) for 8 weeks. MATERIALS AND METHODS: Paired pre- and post-ketogenic diet MR spectroscopy data from both the lesion and contralateral hemisphere were analyzed using LCModel software in 10 patients. RESULTS: At baseline, the ketone bodies acetone and ß-hydroxybutyrate were nearly undetectable, but by week 8, they increased in the lesion for both acetone (0.06 ± 0.03 ≥ 0.27 ± 0.06 IU, P = .005) and ß-hydroxybutyrate (0.07 ± 0.07 ≥ 0.79 ± 0.32 IU, P = .046). In the contralateral brain, acetone was also significantly increased (0.041 ± 0.01 ≥ 0.16 ± 0.04 IU, P = .004), but not ß-hydroxybutyrate. Acetone was detected in 9/10 patients at week 8, and ß-hydroxybutyrate, in 5/10. Acetone concentrations in the contralateral brain correlated strongly with higher urine ketones (r = 0.87, P = .001) and lower fasting glucose (r = -0.67, P = .03). Acetoacetate was largely undetectable. Small-but-statistically significant decreases in NAA were also observed in the contralateral hemisphere at 8 weeks. CONCLUSIONS: This study suggests that 3T MR spectroscopy is feasible for detecting small cerebral metabolic changes associated with a ketogenic diet, provided that appropriate methodology is used.

Another "great mimicker": FDG-PET/CT imaging findings of sarcoid-like reaction.

Sarcoid-like reaction (SLR) is a cause of non-caseating granulomas in some of the cancer patients with otherwise no signs or symptoms of sarcoidosis. SLR has been described in a variety of solid organ malignancies, including breast and lung cancer. SLR may result in hypermetabolic activity in 18-fludeoxyglucose positron emission tomography (PET)/CT scan, resulting in false positive reporting for malignancy. The purpose of this case series is to expose residents/practising physicians who interpret PET/CT to a series of cases illustrating findings of SLR.

Spectroscopic research on ultrahigh pressure (UHP) macrodiamond at Copeton and Bingara NSW, Eastern Australia.

Millions of macrodiamonds were mined from Cenozoic placers across Eastern Australia, 98% from within the Copeton and Bingara area (85 km across) in the Phanerozoic New England region of New South Wales (NSW). Raman spectroscopy of inclusions in uncut diamond, from the Copeton and Bingara parcels, identifies them as ultrahigh pressure (UHP) macrodiamond formed during termination of subduction by continental collision. Infrared spectral properties of the two parcels are critically similar in terms of nitrogen abundance (low in zoned diamond, high in unzoned diamond), requiring a pair of different growth mechanisms/protoliths. Within each parcel, the degrees of nitrogen aggregation are relatively strong and coherent, but they are so different from each other (moderate aggregation for Bingara, strong for Copeton) that the two parcels require separate primary and local sources. The local sources are post-tectonic alkali basaltic intrusions which captured UHP minerals (garnet, pyroxene, diamond) from eclogite-dominated UHP terranes (density stranded at depth-mantle, lower crust). X-ray diffraction studies on Copeton diamond indicate a normal density, despite previous reports of anomalously high density. For non-fluorescent diamond, a 2nd order Raman peak, which is prominent in theoretical perfect diamond and in African cratonic diamond, is suppressed in Copeton and Bingara UHP macrodiamond. Pervasive deformation during macrodiamond growth probably causes this suppression, the strong nitrogen aggregation, and the exceptional durability documented through industrial use.

Maturation and fertilization in Lottia gigantea oocytes: intracellular pH, Ca(2+), and electrophysiology.

Intracellular pH and Ca(2+) were measured with BCECF- and Calcium Green-dextran during maturation and fertilization of oocytes of the limpet Lottia gigantea. Maturation of oocytes from prophase to metaphase I of meiosis was induced in seawater adjusted to pH 9 with NH(4)OH. Intracellular pH rose during maturation induction, and maturation was also induced by microinjecting pH 8, but not pH 7, HEPES buffer. Intracellular Ca(2+) rose during NH(4)OH-induced maturation, but maturation was not inhibited when the increase was blocked by microinjection of BAPTA. When the metaphase I oocytes were fertilized(), there was an abrupt increase in intracellular Ca(2+), and activation (polar body formation) failed to occur in BAPTA-injected oocytes. Intracellular pH did not rise during fertilization. These observations show that maturation from prophase to metaphase I of meiosis is pH-dependent and activation of the metaphase I oocytes is Ca(2+)-dependent. A Ca(2+) action potential was present in both immature and mature oocytes but was more prominent in mature oocytes whose input resistance was higher. Fertilization produced a long-lasting (17-20 min) Na(+)-dependent fertilization potential with superimposed oscillations resembling Ca(2+) action potentials.

Radionuclide lung imaging in respiratory decompression sickness: potential role in the diagnosis and evaluation of hyperbaric therapy.

Of the more than 3.5 million trained divers in the United States, many will experience various illnesses specific to divers. Most of these illnesses are related to the changes in absolute pressure that divers experience while diving. During and after ascent, a diver is at risk for decompression sickness and pulmonary barotrauma. A very rare casualty is pulmonary decompression sickness from immersion. This is a literature review and case report of a young woman with acute respiratory decompression sickness who had defects on perfusion lung imaging after a diving accident and after hyperbaric oxygen therapy. However, the perfusion defects reverted to normal in less than 24 hours. Possible explanations for the changes in the appearances of the scans are offered and discussed. This case report shows the potential utility of lung scanning in the diagnostic examination of these patients and the evaluation of the adequacy of treatment with hyperbaric oxygen therapy. A greater use of ventilation-perfusion lung scans in the treatment of such patients may establish its role more definitely.

Technetium-99m sestamibi uptake in a maxillary brown tumor.

Brown tumors have been reported to take up TI-201 when dual-tracer parathyroid scintigraphy using TI-201 and Tc-99m pertechnetate was performed. With the change to the more favorable Tc-99m sestamibi parathyroid scanning, similar phenomena of tracer uptake in brown tumors have been reported. The authors describe a 44-year-old man with a left maxillary swelling. Laboratory investigations revealed elevated parathyroid hormone levels. Computed tomography of the head showed a left maxillary expansile mass. Subsequently, a Tc-99m sestamibi scan was performed to rule out a parathyroid adenoma. Left inferior parathyroid retention of the tracer was seen, indicating a parathyroid adenoma. An incidental finding was the uptake of Tc-99m MIBI in the left maxillary brown tumor. This case suggests the utility and possible specificity of Tc-99m MIBI uptake in diagnosing brown tumors.

Potential pitfall in parathyroid sestamibi imaging resulting from a cardiac pacemaker.

A 47-year-old woman with a history of end-stage renal disease and hyperparathyroidism after total parathyroidectomy had Tc-99m sestamibi imaging to identify possible ectopic parathyroid tissue. This study was prompted by increasing calcium and parathyroid hormone levels after several years of taking calcium supplements necessitated by a surgically induced hypoparathyroid state and end-stage renal disease. The scan showed persistent linear activity in the upper right mediastinum in delayed images, after washout of the thyroid had occurred. Because of the unusual configuration of this finding, investigation of the patient's clinical history and other imaging studies was undertaken. The authors concluded that the unusual mediastinal uptake was not hyperactive parathyroid tissue, but rather was attributed to the presence of central venous pacemaker wires. Thus, this case illustrates a potential pitfall in parathyroid sestamibi imaging, the uptake of which may increase in the presence of a cardiac pacemaker, and it emphasizes the importance of correlative imaging.

Augmented enterocystoplasty for neurogenic bladder associated with renal transplantation: appearance on Tc-99m MAG3 renal transplant scan.

Enterocystoplasty (bladder augmentation) is a method of increasing bladder capacity in patients with small or neurogenic bladders in order to prevent vesicoureteral reflux. In patients with poorly compliant bladders, enterocystoplasty, which consists of a segment of detubularized small bowel or a portion of the stomach attached to the bladder, often helps to reduce the intravesicular pressures, thus reducing the likelihood of infection. It is also useful in treating bladder dysfunction in children with end-stage renal disease who require renal transplantation. Radiographic evaluation of patients with a renal transplant and augmented bladder often can be confusing, and may suggest a urine leak or hematoma. We report a patient with a renal transplant, bladder augmentation, and rising serum creatinine who underwent renal scintigraphy and ultrasonography.

Intussusception secondary to Meckel's diverticulum detection with Tc-99m monoclonal antibodies to granulocytes (Leukoscan).

A case of Meckel's diverticulum causing intussusception in an 8-year-old boy is presented. The Meckel's diverticulum was detected by using a Tc-99m-labeled antigranulocyte monoclonal antibody MN3 (Leukoscan; Immunomedics, Morris Plains, NJ), which is under clinical evaluation for the detection of atypical appendicitis at the authors' institution. Pathologic evaluation confirmed Meckel's diverticulitis with ileal-ileal intussusception.

Scintigraphic manifestations of "sternal cupping".

Sternal abnormalities in sickle-cell disease have been documented by bone scintigraphy and radiography in patients with homozygous sickle-cell anemia, but not in patients with sickle-thalassemia. We present here two unusual cases of sternal abnormalities in complicated sickle-cell disease. One is an infant with radiographic findings of "sternal cupping" and transient hypo-ossification of the sternum and sickle-thalassemia. The other patient is also a male infant with unusual, persistent under-ossification of bone, in association with radiographic findings of "sternal cupping." The second patient also had a 4P-chromosomal defect (Wolf-Hirschhorn syndrome) in which sternal hypo-ossification was described.

Scintigraphic findings of osteomyelitis after intraosseous infusion in a child.

A case of unilateral tibial osteomyelitis in a 20-month-old child after bilateral intraosseous infusion (IOI) needle placement is presented. A review of the indications, potential complications, and scan findings is discussed. This case also shows the lack of significant uptake in the noninfected side, suggesting that a three-phase bone scan is of value in differentiating reactive bone from infected bone in patients with IOI.

Value of single-photon emission-computed tomography in acute stroke therapeutic trials.

BACKGROUND AND PURPOSE: New therapeutic interventions for acute ischemic stroke are aimed at improving cerebral blood flow in the first 3 to 6 hours after symptom onset. Single-photon emission-computed tomography (SPECT) performed in the setting of clinical therapeutic trials may give us a better understanding of the physiological response to new forms of treatment and could impact acute management decisions. METHODS: We prospectively studied 15 patients with hemispheric ischemic stroke with SPECT within 6 hours of symptom onset and again at 24 hours. The ischemic defect was assessed in a semiquantitative manner that used computer-generated regions of interest (SPECT graded scale). This measure was correlated with clinical presentation (National Institutes of Health [NIH] Stroke Scale), initial clinical course (change in NIH Stroke Scale), long-term outcome (Barthel Index at 3 months), and complications of cerebral hemorrhage and edema. RESULTS: The severity of the SPECT graded scale on the admission scan correlated with the severity of neurological deficit (admission NIH Stroke Scale) (P < .05) and was positively associated with poor long-term outcome as measured with the Barthel Index (P < .001) and the complications of cerebral hemorrhage and massive cerebral edema (P < .005). In fact, there was a threshold value for the SPECT graded scale above which all patients suffered poor long-term outcome and the complications of cerebral hemorrhage and edema. CONCLUSIONS: The measurement of an ischemic defect using SPECT is a valid assessment of hemispheric stroke severity in the hyperacute setting and may be useful for selecting or stratifying patients in clinical therapeutic trials.

Should hypertension be treated after acute stroke? A randomized controlled trial using single photon emission computed tomography.

OBJECTIVE: To determine if previously hypertensive patients with acute ischemic stroke should be treated with antihypertensive medication in the immediate poststroke period. DESIGN: Randomized double-blind, placebo-controlled trial. SETTING: Sixteen consecutive hypertensive patients (four men and 12 women; mean age, 66 years [age range, 46 to 83 years]) with middle cerebral artery infarction within 72 hours of onset and blood pressure between 170 and 220 mm Hg(systolic) and 95 and 120 mm Hg (diastolic). INTERVENTION: Placebo (n = 6), nicardipine hydrochloride (20 mg [n = 5]), captopril (12.5 mg [n = 3]), or clonidine hydrochloride (0.1 mg [n = 2]) given every 8 hours for 3 days. MAIN OUTCOME MEASURES: Decline in blood pressure, change in cerebral blood flow as measured by single photon emission computed tomography, and clinical change as determined by the National Institutes of Health Stroke Scale. RESULTS: Blood pressure fell significantly in both the drug-treated group as a whole and in those patients receiving placebo (P < .001). There was no difference in blood pressure levels between these two groups throughout the study period. Patients receiving nicardipine had a consistently lower pressure than the other groups. A significant negative relationship was noted between the maximum blood pressure fall and improvement in cerebral blood flow. There were four patients whose blood pressure dropped by more than 16% of the baseline value on any 24 hours in the first 3 days. All either failed to increase or actually decreased their cerebral blood flow to the affected area. Three of these patients were treated with nicardipine. There was no significant difference in clinical course between the placebo-and drug-treated groups as a whole. CONCLUSIONS: Hypertensive ischemic stroke patients with a moderate elevation of blood pressure in the first few days may not require antihypertensive therapy. Nicardipine and possibly other calcium channel blockers may cause an excessive fall in blood pressure and impair cerebral blood flow in these patients and should therefore be used with caution.

Evaluation of soft tissue injury by Tc-99m bone agent scintigraphy.

Six patients with soft tissue injury secondary to different etiologic factors are presented. The degree and extent of tissue necrosis was precisely identified by scintigraphy. In two of these, radionuclide imaging helped to establish accurately the level of amputation that resulted in appropriate wound healing.

Bone scintigraphy in calcific discitis of childhood.

The bone scintigraphic findings of calcific discitis of childhood is described and one new case is presented. A brief review of the value of bone scintigraphy in the diagnosis of this syndrome as well as pathogenesis, clinical course, and treatment is provided.

Bone scintigraphy in the evaluation of extraskeletal injuries from child abuse.

Bone scintigraphy is a valuable imaging modality in the examination of the battered child. It is often used to evaluate skeletal trauma. However, bone scans may also reveal subtle and unusual scintigraphic findings that, if recognized, can lead to the diagnosis of intracranial, visceral, and soft-tissue injury. Several cases of child abuse in which bone scan findings suggested the presence of injuries other than skeletal trauma are presented.

Caffey's disease: nuclear medicine and radiologic correlation: a case of mistaken identity.

Infantile cortical hyperostosis is declining in incidence. The classical radiograph and bone scan findings have been well described. A case first mistaken for child abuse is presented. The use of bone scanning in the work-up of non-accidental trauma is addressed.