Shoichi Inagawa

Relationship between heart rate and optimal reconstruction phase in dual-source CT coronary angiography.

RATIONALE AND OBJECTIVES To evaluate reconstruction image quality at the systolic and diastolic cardiac phases and determine the optimal phase for reconstruction according to heart rate when using dual-source computed tomography (CT) with 75 ms temporal resolution. MATERIALS AND METHODS We retrospectively reviewed the CT datasets of 35 patients with regular heartbeats who underwent coronary CT angiography. Images were reconstructed in 2% steps between 32 and 78% of the beat-to-beat interval. Two experienced radiologists determined the reconstruction interval with the fewest motion artifacts and the motion score of each vessel for the systolic and diastolic phases. Subgroup analysis was performed in patients having heart rates of <70, 70-80, and >80 beats per minute (bpm). RESULTS In the subgroup with heart rates of <70 bpm, the diastolic phase reconstruction image quality was significantly better than for the systolic phase (P < .01). In the 70-80 bpm and >80 bpm subgroups, no significant difference was observed. In the diastolic phase, the image quality of the <70 bpm subgroup was significantly better than for the >80 bpm subgroup (P < .05). In all systolic phase subgroups and other diastolic phase subgroups, no significant difference was observed. CONCLUSIONS Using a DSCT scanner with 75 ms temporal resolution, reconstruction at the diastolic phases should be used for patients with heart rates <70 bpm. For heart rates >70 bpm, larger studies are necessary to determine whether reconstruction at the systolic, diastolic, or both phases should be used.

Preoperative evaluation of the vertebral arteries and posterior portion of the circle of Willis for cervical spine surgery using 3-dimensional computed tomography angiography.

Study Design. A retrospective analysis using prospectively collected data from 3-dimensional computed tomography angiography (3D-CTA). Objective. To investigate the frequency of anomalous vertebral arteries (VA) and variations of the posterior portion of the circle of Willis (PPCW) using 3D-CTA for preventing perioperative iatrogenic vascular complications. Summary of Background Data. Some studies have reported that preoperative 3D-CTA is useful for determining the VA blood flow in the cervical spine. However, preoperative 3D-CTA has not been used for evaluating PPCW, which functions as vessels collateral to the basilar artery in the case of iatrogenic VA injury. Methods. The study included 100 consecutive patients (61 males and 39 females; mean age, 60.4 ± 15.4 yr; range, 11−86 yr) who underwent cervical decompression and/or instrumentation between April 2008 and May 2012. We measured the diameters of the VA (VAD), posterior communicating artery (PCOMD), first segment of the posterior cerebral artery (P1D), and basilar artery (BAD) twice and determined the frequency of anomalous VA and PPCW variations. Results. Hypoplastic VA, hypoplastic PCOM, and hypoplastic P1 were detected in 11 (11.0%), 81 (81.0%), and 13 patients (13.0%), respectively. Hypoplastic PCOM-P1 and hypoplastic basilar artery were observed in 87 (87.0%) and 3 patients (3.0%), respectively. Overall, 47 patients (47.0%) possessed some degree of abnormal VA blood flow. There were 7 patients (7.0%) with both unilaterally hypoplastic VA and bilaterally hypoplastic PCOM-P1s, in whom iatrogenic VA injury on the dominant side could have caused lethal vascular complications. We termed the hypoplastic VA of the contralateral side without collateral vessels as “critical VA.” Conclusion. The VAs and PPCW vary considerably. Preoperative 3D-CTA provides important information for preventing tragic vascular complications caused by iatrogenic VA injury. Taking the risk of radiation into consideration, we recommend this method for patients at the highest risk for iatrogenic VA injury. Level of Evidence: 4

Correlation between the site of pulmonary embolism and the extent of deep vein thrombosis: evaluation by computed tomography pulmonary angiography and computed tomography venography

PurposeThe aim of this study was to evaluate the relation between the sites of pulmonary embolism (PE) and deep vein thrombosis (DVT) by computed tomography pulmonary angiography (CTPA) and CT venography (CTV) of the pelvis and lower extremities.Materials and methodsWe retrospectively reevaluated CTPA-CTV data sets for 227 consecutive patients suspected of having a PE. The PEs were divided into proximal (located at the lobar artery or proximal to it) and distal groups. DVTs were divided into proximal (located above the knee) and distal groups. Cohen’s kappa statistic and chi-squared tests were performed.ResultsThe incidence of PE was significantly higher in patients with a proximal DVT than with a distal DVT (P < 0.01). In patients with a proximal DVT, the incidence of proximal PE was significantly higher than that of distal PE (P < 0.05). In patients with a proximal DVT, the incidence of PE was significantly higher in patients with a right-side DVT than with a left-side DVT (P < 0.05).ConclusionProximal PEs were correlated with proximal DVTs. Patients with a proximal DVT tended to have a PE, especially with a right-proximal DVT. Hence, the presence of a right-proximal DVT has the potential for serious complications, and carefully diagnosis is required for PE and DVT.

Another Case of Erratic Brain Embolism After Particle Embolization for a Giant Intrathoracic Solitary Fibrous Tumor

To the editor, In addition to the case reported by Patel et al. [1], we experienced another occurrence of erratic brain embolism after particle embolization for a giant intrathoracic solitary fibrous tumor and would like to give notice anew to all of our colleagues on the risk related to this procedure. It was in a woman in her early 60s who presented with dyspnea at walking and exercise. No major previous history was noted except a surgical extirpation of myoma uteri and systemic hypertension. CT revealed a giant tumor, which occupied the right thoracic cavity and compressed the right lung with the mediastinum deviated to the left. Needle biopsy brought about a diagnosis of solitary fibrous tumor. Dynamic contrast-enhanced CT showed that the mass was hypervascular (Fig. 1A) and fed by the right lateral thoracic artery and the right internal mammary artery. Surgical removal of the tumor with preoperative embolization on the preceding day was recommended to the patient and her family and consented by them. In the session of preoperative embolization, the patient was set in the semi-lateral position on her right side and provided with oxygen via mask at 2 L/min. After local anesthesia and puncture of the right femoral artery in the inguinal region, angiography was done to reveal that the right lateral thoracic artery (Fig. 1B) and the right internal mammary artery were dilated and fed the enlarged tumor vessels. No vessel in the normal right lung was visualized with injection from any of these two feeders. The distal segment of the right lateral thoracic artery was reached and almost one vial of trisacryl gelatin microspheres (Embosphere, Nippon Kayaku Co., Ltd./Merit Medical Systems, Inc., Tokyo) of 300–500 mm in size was administered as well as additional free coils with no adverse effect. The right internal mammary artery was then distally secured and one-quarter vial of the same particulate material was administered. The patient began to complain of postural discomfort. Oxygen saturation decreased below 80% and then got recovered to normal after immediate tracheal intubation. Embolization was abandoned. Immediate CT scanning of the head and the thoracoabdominal region through the lower extremities revealed no new abnormality except tiny low densities in the spleen, which we did not notice on site but retrospectively later on. No abnormality in the residual left lung, nor pulmonary artery thromboembolism, nor deep venous thrombosis in the lower extremities was shown. In the intensive care unit, the patient moved her extremities intentionally when the effect of sedation subsided. Postponement of the surgery seemed to exacerbate her respiratory condition and let her lose a chance of recovery, and surgical removal of the tumor on & Shoichi Inagawa sinagawa@med.niigata-u.ac.jp

Evaluation of the optic nerve complex in the orbit using coronal Fast Magnetic resonance Imaging

Recently available coronal fast magnetic resonance imaging (MRI) has very high spatial resolution with good contrast between the optic nerves and cerebrospinal fluid (CSF). The aim of this study was to evaluate the diagnostic value of coronal fast imaging in optic nerve diseases. Thirty-five patients with various Neuro-ophthalmic conditions including 9 with optic neuritis, 6 with optic atrophy, 5 with glaucoma, 4 with segmental optic nerve hypoplasia and 11 with other optic neuropathies including orbital apex syndrome were evaluated with the three-dimensional fast imaging employing steady-state acquisition (FIESTA) sequence in addition to standard MRI protocols. The optic nerve complexes were evaluated on coronal images of the orbits. Detailed demonstration of the optic nerve complex—the optic nerve, the perineural CSF space and dural sheath—could be readily obtained with FIESTA sequence. The acute phase of both optic neuritis and perineuritis showed enlargement of the perineural CSF space; the optic nerve was swollen in optic neuritis but not in perineuritis. Cases of optic atrophy and glaucoma showed perineural CSF space enlargement with normal optic sheath circumference and a thinner optic nerve, while optic nerve hypoplasia showed a smaller dural sheath circumference without perineural CSF space enlargement. In the cases of orbital apex syndrome optic nerve compression by the extraocular muscles was clearly shown. Coronal FIESTA imaging of the orbit is capable of delineating detailed structural changes in the optic nerve complex and is of diagnostic value for the differentiation of optic nerve diseases.