Jiro Watarai

Diffusion changes in a tumor and peritumoral tissue after stereotactic irradiation for brain tumors: possible prediction of treatment response.

Objective: Changes in apparent diffusion coefficient (ADC) in a tumor and peritumoral tissue after stereotactic irradiation (STI) were evaluated, and then the therapeutic efficacy of ADC measurement was assessed. Methods: In 20 tumors, diffusion-weighted imaging within 1 week before and 2-4 weeks after STI was performed. The normalized ADC (nADC) was measured. The nADCs in the tumor and peritumoral region before STI were compared with those after STI and the change in tumor nADC compared with the change in tumor size. Results: The nADC of the tumors was significantly higher 2-4 weeks after STI compared with that before STI. The nADC of the peritumoral regions 2-4 weeks after STI did not differ significantly from that before STI. A significant difference in the nADC at 2-4 weeks after STI was observed between the responder and nonresponder groups. Conclusions: Changes in nADC as measured by diffusion-weighted imaging can predict response to STI.

Normal variations of the temporal bone on high-resolution CT: Their incidence and clinical significance

We evaluated normal variations of the temporal bone on high-resolution computed tomograms (HR-CTs) and investigated their incidence. HR-CTs of the temporal bones of 325 patients were retrospectively reviewed. Six groups of variants, which were considered important for presurgical planning, were evaluated on HR-CTs. These included: (1) an incomplete bony covering of a high-positioned jugular bulb; (2) severe asymmetry of the jugular foramen; (3) an anteriorly located sigmoid sinus; (4) a deep sinus tympani; (5) a large internal auditory canal; and (6) a large cochlear aqueduct. The frequency of the variations were as follows: (1) 2.4%; (2) 4.0%; (3) 1.6%; (4) 5.9%; (5) 2.3%; and (6) 3.0%. Bilateral involvement with variation (4), (5) and (6) was frequently seen. Normal anatomical variations of the temporal bone are therefore not rare and awareness of the possible variants is necessary before surgery of the inner ear, middle ear and posterior fossa.

Ischemic lesions related to cerebral angiography: Evaluation by diffusion weighted MR imaging.

Abstract. We examined the incidence of ischemic lesions occurring after cerebral angiography by means of diffusion weighted MR imaging (DWI). Fifty patients were included in this study. Balloon occlusion tests of the internal carotid artery were performed in 9 of the 50 patients. DWI was performed on the same day as the cerebral angiography or on the following day. No new neurological deficits were found after cerebral angiography. However, 13 of the 50 cases revealed new ischemic lesions after cerebral angiography. The incidence of ischemic lesions was significantly different between patients who underwent balloon occlusion tests and patients who did not. The incidence of ischemic lesions was not influenced by the duration of the procedure, use of additional catheters, total amount of contrast material or the type of contrast material. The incidence of clinically silent ischemic lesions related to cerebral angiography is greater than the incidence of neurological complications. In patients who underwent occlusion tests of the internal carotid artery, the incidence of silent lesions was significantly higher than in patients who did not.

Craniocervical junction venous anatomy around the suboccipital cavernous sinus: evaluation by MR imaging

The present study evaluated the venous anatomy of the craniocervical junction, focusing on the suboccipital cavernous sinus (SCS), a vertebral venous plexus surrounding the horizontal portion of the vertebral artery at the skull base. MR imaging was reviewed to clarify the venous anatomy of the SCS in 33 patients. Multiplanar reconstruction MR images were obtained using contrast-enhanced three-dimensional fast spoiled gradient–recalled acquisition in the steady state (3-D fast SPGR) with fat suppression. Connections with the SCS were evaluated for the following venous structures: anterior condylar vein (ACV); posterior condylar vein (PCV); lateral condylar vein (LCV); vertebral artery venous plexus (VAVP); and anterior internal vertebral venous plexus (AVVP). The SCS connected with the ACV superomedially, with the VAVP inferolaterally, and with the AVVP medially. The LCV connected with the external orifice of the ACV and superoanterior aspect of the SCS. The PCV connected with the posteromedial aspect of the jugular bulb and superoposterior aspect of the SCS. The findings of craniocervical junction venography performed in eight patients corresponded with those on MR imaging, other than with regard to the PCV. Contrast-enhanced 3-D fast SPGR allows visualization of the detailed anatomy of these venous structures, and this technique facilitates interventions and description of pathologies occurring in this area.

Primary sarcoma of the aortic wall

Pr imary tumors o f the aort ic wa l l are unusual . B e c a u s e o f their rar i ty and the fact that these tumors can m i m i c var ious o the r c l in ica l cond i t ions such as a therosc le ro t i c disease, d i s sec t ing aneu rysm, o r coarc ta t ion , they are s e l d o m suspec ted and d i a g n o s e d p r e -ope ra t i ve ly or dur ing a n t e m o r t e m e x a m i n a t i o n [1]. T o date, a f e w rad io log ica l ly w e l l d o c u m e n t e d cases o f these tumors h a v e been repor t ed [ 2 4 ] .

Angiography of Hepatic Vascular Malformations Associated with Hereditary Hemorrhagic Telangiectasia

AbstractPurpose: To describe the angiographic features of hepatic involvement in hereditary hemorrhagic telangiectasia (HHT), particularly the presence of portovenous shunts. Methods: We reviewed the angiographic findings of seven patients with HHT. The patients comprised three women and four men with a mean age of 51 years. Results: Intrahepatic telangiectasias were found in all seven patients and shunts between three vascular channels were found in six of seven patients. In the four patients who had portovenous shunts combined with arterioportal shunts, the portovenous shunts were large. Three patients had no portovenous shunts. Two of these patients had arteriovenous shunts, and one had no shunt. The mean age (69 years) of the patients with portovenous shunts was older than those without portovenous shunts (26 years). Conclusions: Hepatic vascular lesions in HHT are varied, ranging from telangiectasias to large shunts between three vascular channels. In an advanced stage of involvement, large portovenous shunts are present.

Comparison of MR imaging and CT in discriminating tumor infiltration of bone and bone marrow in the skull base

We compared MR imaging with CT in revealing tumor infiltration of bone and bone marrow in the skull base of 54 patients. MR imaging had no advantages over when tumor involved the anterior compartment. However, precontrast T1-weighted MR images were more efficient than CT in 37.5% of tumors involving the middle compartment and in 54.5% of tumors involving the posterior compartment, respectively. Precontrast T1-weighted images were more accurate than other pulse sequences in revealing bone and bone marrow that were replaced by tumors.

CT of Retropharyngeal Lymph Node Metastasis from Maxillary Carcinoma

CT findings for retropharyngeal lymph node metastasis in 25 patients with histologically proven carcinoma of the maxillary sinus and with no prior treatment were evaluated retrospectively. Four lateral retropharyngeal node metastses (16%, 4/25) could be identified by CT. All retropharyngeal metastatic nodes were located between the ipsilateral internal carotid artery and the longus colli muscle at the level of the first cervical vertebral body. The metastatic nodes ranged from 8 mm to 35 mm in size at the long axis. The risk of retropharyngeal node metastasis depends on the degree of carcinoma involvement to the posterior nasal cavity, the posterior ethmoid sinuses, the sphenoid sinuses, the palate (soft and hard) and the nasopharynx. This study indicates that CT is useful for detecting these lymph node metastases.

CT Features of Pancreatic Fistula After Pancreaticoduodenectomy

OBJECTIVE Our objective was to establish the CT features that are indicative of pancreatic fistula after pancreaticoduodenectomy. CONCLUSION A fluid collection seen on CT around the pancreaticojejunostomy site and in the pancreatic bed may be caused by pancreatic fistula in patients who have undergone pancreaticoduodenectomy. CT depiction of air bubbles in the fluid at these sites may strongly suggest the diagnosis of pancreatic fistula.

Reduced perfusion reserve in Leukoaraiosis demonstrated using acetazolamide challenge 123I-IMP SPECT.

Objective: We examined the relationship between the perfusion reserve as measured by acetazolamide (ACZ)-challenge N-isopropyl-I-123-p-iodoamphetamine (IMP)-single-photon emission computed tomography (SPECT) and the degree of leukoaraiosis (LA) as estimated using magnetic resonance imaging. Methods: In 51 patients receiving 123IMP-SPECT with the resting state and ACZ challenge, the unaffected cerebral hemispheres were included in the present study. Mean cerebral blood flow (CBF) in the resting state and ACZ reactivity were acquired. Absolute CBF value and ACZ reactivity were compared among patients with LA grades 0, 1, and 2. The relationship between mean age and LA grade was also assessed. Results: No significant difference in the absolute CBF value in the resting state was observed among the 3 LA groups. Although vasoreactivity in LA grade 0 did not differ from that in grade 1, vasoreactivity in LA grade 2 was significantly lower (P < 0.05) than that in grades 0 or 1. Conclusions: The perfusion reserve is impaired in advanced LA.