Kazumasa Hayasaka

Dialyzability of gadodiamide in hemodialysis patients

PurposeThe aim of this study was to evaluate the contrast enhancement, pharmacokinetics, dialyzability, and safety of gadodiamide in patients on hemodialysis.Materials and methodsThirteen hemodialysis patients with abdominal disease were examined after receiving intravenous gadodiamide (0.1 mmol/kg body weight) by magnetic resonance imaging (MRI) and were dialyzed at l, 3, 5, and 8 days. Blood samples were obtained immediately before, during, and at the end of the first hemodialysis session and immediately before and at the end of the next three sessions. The complete blood count, blood biochemistry, β2-microglobulin, and gadolinium were measured. Dialysis of urea, creatinine, and gadolinium during the first hemodialysis session was assessed. Precontrast and postcontrast MRI and Gd-enhanced MR angiography (MRA) images were reviewed and visually evaluated by two radiologists; their evaluation was based on consensus.ResultsGadodiamide did not cause any changes in renal function. An average of 73.8%, 92.4%, and 98.9% of the gadodiamide dose was eliminated by the end of the first, second, and third hemodialysis sessions, respectively. The average half-time of gadodiamide was 1.93 h (SD 0.55). The mean clearance of gadodiamide during hemodialysis was 63.5 ml/min (SD 21.9). There were no side effects related to the injection of gadodiamide. In all cases, diagnosable MRI and MRA images were obtained after gadodiamide injection in the hemodialysis patients.ConclusionIn hemodialysis patients, gadodiamide achieves diagnosable images. It is dialyzable and can be used safely without measures to increase excretion.

Heat and pain sensations induced by arterial injection of low-osmolality contrast media: a comparison of patients' discomfort with ionic saline, nonionic glucose, and vasodilator nitrate.

C linical symptoms such as heat and pain are two of the most frequent and finpleasant adverse effects experienced after intravascular injection of iodinated contrast media. Recently, nonionic dimeric contrast media (iotrolan, iiodixanol) have been developed [1], and their osmolality has been reduced to the physiologic level. However, subjective discomforts associated with these contrast media have not yet been eliminated. Although it has been established that heat and pain are caused mainly by tile high osmolality of the contrast media [2], it is possible that other factors also may play active roles. The aim of this study was to determine what factors and mechanisms are involved in causing heat and pain from the administration of the contrast media presently being used. The following agents were analyzed in our study: glucose as a model of a nonionic agent, saline (NaCl) as a model of an ionic agent, and nitrate as a vasodilator. Clinical studies on heat and pain induced by contrast media have been conducted [1, 3-7], but studies with test solutions involving actual patients have not been reported [8, 9]. Our study was designed to obtain the expression of sensations, which could be obtained only from human volunteers.

Primary pituitary lymphoma diagnosis by FDG-PET/CT.

Primary pituitary lymphoma is extremely rare. We describe a 71-year-old man who presented with appetite loss and sudden visual loss. Brain magnetic resonance imaging showed a mass at the pituitary gland that was moderately and homogeneously enhanced with contrast media. F-18 fluorodeoxyglucose positron emission tomography combined with CT (FDG-PET/CT) performed for a systemic survey revealed focal moderate FDG uptake only in the pituitary gland. The mass was histologically diagnosed as non-Hodgkin lymphoma from a biopsy of the pituitary gland.

Gadolinium-enhanced dynamic MRI of breast hemangioma

We describe a patient with hemangioma of the breast. The tumor showed an Ill-defined hypointense mass on T1-weighted imaging and hyperintense mass on T2-weighted imaging. After bolus gadolinium injection, the tumor showed heterogeneous enhancement in early phase and in the time-intensity an early intensive enhancement was followed by a plateau. This intensive enhancement in the early phase is not limited to breast carcinoma but can be found in breast hemangiomas as well.

Dynamic MR imaging of splenic tumor

Inflammatory pseudotumor and hemangioma of the spleen are rare benign tumors, and MRI findings of splenic diseases have been reported only rarely. We recently observed three patients with inflammatory pseudotumor and hemangioma of the spleen. Abdominal ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI) and angiography demonstrated within the enlarged spleen. MRI and dynamic MRI after administration of gadolinium DTPA provide the characterization of the splenic tumor.

Usefulness of F-18 FDG-PET in detection of multiple endocrine tumors with duodenal carcinoid

In a 76-year-old woman in whom hypercalcemia had been followed, whole body fluorodeoxyglucose positron emission tomography (FDG-PET) scan detected hypermetabolic areas in the left lower region of the thyroid gland, pancreas tail, and duodenum. CT, MR, biopsy, and surgery were performed and parathyroid adenoma, pancreatic gastrinoma, and duodenal carcinoid were diagnosed. Fluorine-18 (F-18) FDG-PET may be useful for diagnosis of multiple endocrine tumors with duodenal carcinoid.

Intralobar pulmonary sequestration receiving arterial supply from the superior mesenteric artery: A case report

We report a case of congenital anomaly of pulmonary sequestration by contrast-enhanced three-dimensional magnetic resonance (MR) angiography and digital subtraction angiography (DSA). The pulmonary sequestration receives a blood supply from the superior mesenteric artery. MR angiography technique has been employed in pulmonary sequestration.

Hepatic angiomyolipoma: value of breath hold 2D FLASH GD-dynamic imaging with fat saturation

A case of hepatic angiomyolipoma in a 61-year-old woman is reported. Findings on ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging are presented and the usefulness of breath hold 2D FLASH Gd-dynamic imaging with fat saturation is discussed.

FDG PET imaging in a patient with primary seminoma of the prostate.

Primary seminoma of the prostate is extremely rare. We describe a case of a 35-year-old man who presented with difficulty in urinating. Physical findings were unremarkable, but a rectal examination revealed a slightly hardened prostate with a nodule in the right lobe. Blood parameters were normal; however, blood chemistry revealed slightly elevated lactic dehydrogenase, and microscopic hematuria was evident. Serum prostate acid phosphate, carcinoembryonic antigen, and alpha-fetoprotein values were within normal limits. Both computed tomography and magnetic resonance images revealed a large mass in the prostate gland. A prostatic sarcoma or malignant lymphoma was initially suspected. A systemic survey using 18-fluoro-2-deoxyglucose (F-18 FDG) positron emission tomography revealed focal FDG uptake in the prostate gland. A prostatic biopsy of the mass was histologically diagnosed to reveal an extragonadal seminoma.