Hisao Itoh

CT features of retroperitoneal neurilemmoma

PURPOSE The aim of this study was to characterize the CT features of retroperitoneal neurilemmoma. METHODS The CT findings were reviewed in seven patients with retroperitoneal neurilemmoma. RESULTS All of the tumours were well-demarcated round or oval masses. In five cases, heterogeneous contrast enhancement was noted after contrast medium administration. Areas of minimal enhancement reflected diffuse edema in one tumour. Areas without definite enhancement represented prominent cyst formation in three tumours. There were three cases with tumour calcification (two with punctate calcification and one with mottled calcification). CONCLUSION CT findings may suggest the diagnosis of retroperitoneal neurilemmoma preoperatively.

Ga-67 citrate scintigraphy for the early detection of radiation pneumonitis.

To evaluate the usefulness of Ga-67 citrate scintigraphy in the early detection of radiation pneumonitis, scintigrams from 103 patients who were treated with radiation therapy for lung cancer were retrospectively analyzed with regard to abnormal Ga-67 uptake after radiation therapy in sites other than the original or recurrent tumers. Sixteen (20%) of the 80 asymptomatic cases showed positive Ga-67 scintigrams. All of the other 23 symptomatic cases showed positive Ga-67 scintigrams. Thirteen (57%) of these 23 cases had negative chest radiographs although their Ga-67 scintigrams were positive. Detection of radiation pneumonitis by Ga-67 scintigraphy was significantly earlier than that possible by chest radiography (P < 0.01). These data suggest that Ga-67 scintigraphy is more useful and sensitive than chest radiography for the early detection of radiation pneumonitis.

Diffuse gallium-67 uptake in radiation pneumonitis

To evaluate the clinical usefulness of Ga-67 imaging for the assessment of radiation pneumonitis, 12 patients who had developed radiation pneumonitis after receiving radiotherapy alone for non-small-cell lung cancer from 1979 through 1988 were reviewed. Diffuse bilateral Ga-67 uptake occurred in 5 out of the 12 cases; in the other 7 cases, Ga-67 uptake was confined to the irradiation lung. Conversely, chest radiography showed infiltrates only in the irradiated lung. Histopathology of the lung in four out of the five cases that showed diffuse Ga-67 uptake in the lung, however, revealed that the lung outside the radiation field with Ga-67 uptake was consistent with interstitial pneumonitis induced by radiation. These results suggest that radiation pneumonitis could extend beyond the irradiated lung and that Ga-67 imaging is more useful than chest radiography for the assessment of the spatial extent of radiography pneumonitis.

Periportal high intensity on T2-weighted MR images in acute viral hepatitis.

The frequency and degree of periportal high intensity (PHI) on T2-weighted images in 28 patients (32 MR studies) with acute viral hepatitis were analyzed with regard to the various levels of serum glutamic-oxaloacetic transaminase (SGOT) and clinical phases. Periportal high intensity was found in 16 of 32 MR studies (50%) and no definite PHI was found in 7 studies (22%). Periportal high intensity appeared when the SGOT level was >500 IU or when the phase of the disease was early. Follow-up studies revealed that PHI decreased during clinical recovery. We conclude that the degree of PHI on T2-weighted images reflects the severity of the disease in acute viral hepatitis.

Early and Delayed I-123 Imp Spect in Epileptic Patients with Partial Seizures and Normal Ct

Forty-six epileptic patients with partial seizures and normal CT underwent 48 examinations of early and delayed SPECT using I-123 IMP in the interictal phase. One of them underwent a follow-up SPECT in a more stable state compared to the first SPECT. Another patient, with informed consent, underwent a follow-up SPECT in combination with pharmacologic activation with bemegride. Early SPECT was performed 30 minutes after an IMP Injection and delayed SPECT 4 to 4 1/2 hours later. Temporal changes in uptake pattern were visually classified into six types and compared with known patterns of SPECT uptake in relation to ischemic, hyperemic, and other changes. These were also correlated with the amount of epileptic activity seen on the EEG.

Myocardial imaging with I-123 MIBG and Tl-201 demonstrates denervated but viable myocardium in a patient with myocarditis.

The authors present a case of myocarditis. Myocardial scintigraphic studies with I-123 MIBG and TI-201 were performed in the convalescent phase. I-123 MIBG myocardial imaging demonstrated prominent defects in the anterior wall and septum. The authors assume that there is denervated but viable myocardium after an episode of myocarditis.

Dissociation between In-111 chloride and Tc-99m colloid bone marrow scintigraphy in refractory anemia with excess blasts.

Marked renal uptake of ln-111 was found in a patient with refractory anemia with excess blasts (RAEB). A 46-yearold man was admitted to the hospital with severe anemia and splenomegaly. Bone marrow scintigraphy was performed using ln-111 chloride and Tc-99m tin colloid, and there was a strikingly different distribution between these two agents. A bone marrow aspirate from the sternum revealed myeloid dominant hypercellularity with excess blasts, and he was finally diagnosed as having RAEB. Repeated blood transfusions resulting in a saturation of transferrin seemed to be a cause of the dissociation.

Ga-67 SPECT in primary tumors of the head and neck.

Direct and endoscopic inspection revealed no tumor of the pharynx in a 43-year-old man with left cervical lymphadenopathy. Percutaneous aspiration biopsy of a lymph node showed squamous cell carcinoma. Blind biopsy of the pharynx and contrast-enhanced computed tomography (CT) failed to identify a primary tumor. Ga-67 SPECT revealed increased uptake in the left palatine tonsil, and a biopsy of it showed squamous cell carcinoma.

Coal worker's pneumoconiosis mimicking pulmonary sarcoidosis.

The authors describe a 63-year-old coal miner with pneumoconiosis. Ga-67 citrate scanning demonstrated intense uptake in both pulmonary hilar regions extending into the right paratracheal region with diffusely increased activity of the pulmonary parenchyma, mimicking the gallium image of sarcoidosis

Assessment of hepatic excretory function in chronic liver disease by hepatobiliary scintigraphy

Hepatobiliary scintigraphy was performed in 23 normal subjects and 47 patients with chronic liver disease (chronic hepatitis; n=27, liver cirrhosis; n=20) to evaluate its availability as a test of liver function. After intravenous administration of Tc-99m N-pyriodxyl-5-methyl-tryptophan, the data were acquired for 60 min and the time-activity curves of ROIs (the heart and liver) were generated. In two compartment model simulation, the early blood clearance rate (kl), late blood clearance rate (km), hepatic uptake rate (ku), hepatic excretion rate (ke), and hepatic excretion T 1/2 were calculated. There was no significant difference in those fourk values in normal and chronic hepatitis. However, in liver cirrhosis each of them, exceptkm, was lower than in normal subjects. Thekl value correlated closely with the indocyanine green plasma clearance test, whereas theke and T 1/2 values were closely correlated with the level of serum bilirubins. Only hepatobiliary scintigraphy showed the excretory function of the liver quantitatively and theke value was helpful in detecting hepatic excretory dysfunction early in chronic liver disease before serum bilirubins increased.