Yutaka Imai

Diffusion-weighted MR Neurography of the Brachial Plexus: Feasibility Study

The University Medical Center Utrecht institutional review board approved this study, and informed consent was obtained from all subjects. The purpose of this study was to introduce and assess diffusion-weighted (DW) magnetic resonance (MR) neurography for imaging of the brachial plexus. DW MR neurographic images were displayed with a maximum intensity projection technique. DW MR neurography was evaluated in five healthy volunteers and five patients. DW MR neurography showed a long trajectory of the brachial plexus in all healthy volunteers. In all patients, DW MR neurography clearly showed the location of the disease. The proposed DW MR neurography technique can be used to obtain an overview image of the brachial plexus, with excellent conspicuity of the nerves and surrounding structures.

Diffusion-weighted magnetic resonance imaging of the liver using tracking only navigator echo: feasibility study.

Purpose:To introduce and assess the TRacking Only Navigator echo (TRON) technique for diffusion-weighted magnetic resonance imaging (DWI) of the liver. Subjects and Methods:A total of 10 volunteers underwent TRON, respiratory triggered (RT), and free breathing (FB) DWI of the liver. Scan times of TRON and RT DWI were measured, and image sharpness in TRON, RT, and FB DWI was assessed and compared using nonparametric tests. Furthermore, 14 patients with liver metastasis who had undergone TRON and RT DWI of the liver were retrospectively assessed. Relative contrast ratios (RCRs) and apparent diffusion coefficients (ADCs) of the largest hepatic metastasis in TRON and RT DWI were measured. RCRs were compared using a parametric test and agreement in ADCs was assessed using the Bland-Altman method. Results:In the volunteers, mean scan times of TRON and RT relative to FB DWI were 110% to 112% and 261% to 290%, respectively. On axial images, there were no significant differences in images sharpness among TRON, RT, and FB DWI, but on coronal images image sharpness in TRON was nearly always significantly better (P < 0.05) than in RT and FB DWI. In the patients, mean RCRs between TRON and RT DWI were not significantly different (P = 0.9091). Mean difference in ADC ± limits of agreement (in 10−3 mm2/s) between TRON and RT DWI was −0.16 ± 0.79. Conclusion:TRON offers sharp diffusion-weighted images of the liver using an efficient scan time, making it an excellent alternative to RT and FB DWI. The moderate to poor agreement in ADCs of liver metastases between TRON and RT DWI requires further investigation.

DIFFUSE CAVERNOUS HEMANGIOMA OF THE RECTUM : MR IMAGING WITH ENDORECTAL SURFACE COIL AND SPHINCTER-SAVING SURGERY

We describe the clinical features, diagnostic procedures, and treatment of two patients with diffuse cavernous hemangioma of the rectum. Sphincter-saving operations were performed in both patients, with satisfactory results. Magnetic resonance imaging (MRI) with an endorectal surface coil, as well as a conventional body coil, was used to determine the extent of the hemangiomas. We recommend sphincter-saving surgery for the treatment of this benign disease that can cause life-threatening hemorrhage. MRI with an endorectal coil achieves higher-resolution images than conventional MRI.

Clinical usefulness of digital radiography in the gastrointestinal tract: Efficacy of magnification method

We assessed the performance capabilities of image intensifier digital radiography (II DR) in the detection of minute lesions in patients with early stomach cancer. The DR system was a prototype II DR system developed by Toshiba Corp (Tokyo, Japan). This system was able to acquire images with a 1,024-× 1,024-pixel matrix and 13 bits. Radiography was performed using a 0.3-mm tube focus. For the detectability of early stomach cancer, DR was judged to be superior to conventional screen-film system (CFSS) (DR superior, 55.7%; CFSS superior, 22.6%). In depicting the characteristics of the surface of the lesion, DR was also judged to be superior to CFSS (DR superior, 56.6%; CFSS superior, 17.0%). The II DR system used in this study was able to achieve almost the same spatial resolution as conventional radiography using the magnification method. It was also able to visualize subtle findings of early gastric cancer more clearly by the use of postprocessing. In addition, II DR has the advantages of reducing the patient exposure dose and permitting the acquisition of real-time images.

Clinical and experimental studies on the esophagitis due to acid regurgitation

we examined the observation of pathological histology mainly, the climical progress, the observation of gastric camera and the change of the condition of gastric ulcer. To reproduce the mucous membrane of the base of ulcer is a considerably good condition for gastr ic ulcer. The cases of over 6 month after continual internal t rea tment were mostly U1 IV type and not so enough to produce the mucous membrane.

A followup study on twenty-six patients with achalasia of the esophagus undergone esophagomyotomy

Achalasia of the esophagus is considered to be a neuromuscular disorder of the esophageal wall associated with degenerat ive changes in Auerbach s plexus. Therefore , every operative t rea tment is eventually palliative in nature . Recent clinical experience has emphasized tha t the modified Heller operat ion is the procedure of choice in the t r ea tment of achalasia, and the success of the operat ion depends upon the prevent ion of postoperat ive reflux esophagitis and s t r ic ture format ion of the esophagogastric junct ion. The purpose of th is repor t is to present the preand postoperative pathophysiology and the objective evaluation of a postoperative follow-up study. Thir tythree pat ients with achalasia have been t rea ted in Keio Univers i ty Hospital since 1958. As of March, 1966, twenty-six patients have been operated upon by our technique which is a modification of diaphragmoplasty described by Petrovsky in 1962. All of these pat ients were examined by means of cinefluorography and manomet r ic method before and af te r the operation. F rom the stat is t ical analysis of the data obtained, conclusions werer as follows; 1) Better resul ts are obtained in the patients with mild to moderate esophageal dilatation, or the pat ients wi th shor ter durat ion of symptoms 2) Among young individuals in whom the contracti le or propulsive power of the esophagus is relat ively well preserved, both objective and suject ive inprovements are marked if longer myotomy, over 10cm., have been performed. 3) It is considered that the preservat ion of the esophagogastr ic h igh pressure zone and the proper repai r of the hiatus are of supreme importance in prevent ion of postoperat ive reflux exophagitis. Of twen tys ix pat ients operated upon by our technique, 25 (96%) become asymptomatic or improved. In conclusion, to obtain bet ter results , an early surgical intervent ion, preferably a modified Heller operation, is mandatory in the t r ea tmen t of achalasia.

Pathological and clinical observations on achalasia: Quantitative comparison of the ganglion cells in achalasia with normal esophagus

ACHALASIA of the esophagus has been called as cardiospasm or achalasia of the cardia and these nomencula tures are inclined to give misleading impression that lesion of the disease is localized in the gastro-esophageal junctional zone. Many authors have described pathognomonic changes of in t ramura l plexus or Auerbach s plexus only in the lower of the esophagus or the juxta-cardiac region. However only a few repor ts are found in the l i te ra ture concerning quant i ta t ive observat ion of the ganglion cells in t he whole length of the esophagus. Th i s report concerns quant i ta t ive measurement of the ganglion cells in two autopsy cases of achalas ia and one case of normal pat ient for control study. In these three autopsy cases, t ransverse block sections of 5 ram, in thickness were made successively in the whole length of the esophagus. And t h r e e step sections were made f rom every block to count the number of ganglion cells. Maximal number of ganglion cells in these th ree step sections were regarded as representat ive number of each block. In a normal eaophagus examined, ganglion cells appear at the upper end of smooth muscle and increase in number abrupt ly and become most abundant in the segment where smooth and s t r ia ted muscles are mixed wi th equal ratio. The same tendencies are observed in achalasia. However ganglion cells a re degenerated and scanty. Our histologic study shows tha t total gangl ion cell counts in two cases of achalasia are of 3 or 5% of those of normal pat ient and amount to 10 or 16% of normal when ganglionic segment in achalasia is compared with corresponding length of the normal esophagus. The aganglionic areas are observed in the thorac ic and abdominal esophagus distal to 11 or 13 cm. f rom crico-pharyngeus muscle in two cases of achalasia and these levels correspond to tha t of t racheal bifurcation. In none of twenty-eight pa t ien t with the disease, p r imary peristalsis reaches distal ly to the b i furca t ion level in cinefluorographical and manomete t r ic examination. The re fo re dysphagia in achalas ia is not only due to fa i lure of relaxat ion at the gastroesophageal junct ion but also due to aperistalsis in the body of the esophagus below bi furcat ion level, as Wangensteen et al. suggested the name dystonia. It would be worthy to re-emphasize tha t achalasia is the disease ent i ty in almost all uns t r ia ted por t ion of the esophagus and in teres t should not be focussed only upon gastro-esophageal junct ion.