Tumour enhancement with newly developed Mn-metalloporphyrin (HOP-9P) in magnetic resonance imaging of mice.

The purpose of the study is to evaluate the tumour enhancing characteristics and biodistribution of a newly developed metalloporphyrin derivative, HOP-9P (13, 17-bis (1-carboxypropionyl) carbamoylethyl-3, 8-bis (1-phenylpropyloxyethyl)-2,7,12,18-tetra- methyl-porphynato manganese (III)). Seven mice bearing SCC VII tumours were imaged using T1-weighted conventional spin echo magnetic resonance images before and 5 min, 2 h and 24 h after intravenous injection of 0.1 mmol/kg of HOP-9P. For the acquired images, signal intensities of the tumour, muscle and oil-phantom were measured. Then, tumor/oil and tumor/muscle signal intensity ratios were calculated. Nineteen mice were sacrificed before or after the administration of HOP-9P (at 5 min, 2 h and 24 h), and the biodistribution of manganese in the tumour, muscle, liver, blood and kidneys was measured using optical emission spectrometers and was expressed as micrograms of manganese per gram of tissue. The tumour/muscle signal intensity ratio at 24 h (3.18 +/- 0.34) was significantly higher than precontrast ratio (1.77 +/- 0.20) (P < 0.05). The biodistribution assessment of manganese demonstrated that HOP-9P gradually and consistently accumulated in the tumour to reach the highest concentration at 24 h (3.49 +/- 1.22 micro gMn/g). It is concluded that HOP-9P is a potential tumour-specific MR contrast agent.

Assessment of gadolinium-enhanced time-resolved three-dimensional MR angiography for evaluating renal artery stenosis.

OBJECTIVE: The purpose of this study was to assess the image quality of gadolinium-enhanced time-resolved three-dimensional (3D) MR angiography and to evaluate its accuracy in revealing renal artery stenosis. SUBJECTS AND METHODS: Thirty-nine patients underwent MR angiography using an ultrafast 3D Fourier transform spoiled gradient-recalled acquisition in the steady state (TR/TE range, 2.6/0.7--0.8). Five seconds after administration of 15--20 mL gadodiamide hydrate, four or five consecutive data sets with imaging times of 7.0--7.6 sec were acquired during a single breath-hold. A timing examination was not performed. Image quality was assessed using quantitative analysis (signal-to-noise, contrast-to-noise, and venous-to-arterial enhancement ratios) and qualitative analysis (presence of venous overlap, presence of artifacts, and degree of renal arterial enhancement). MR angiography depiction of the renal artery stenosis was evaluated using conventional angiography as the standard of reference. RESULTS: On the best arterial phase, average aortic signal-to-noise ratio (+/-SD) was 74.5 +/- 24.4, aorta-to--inferior vena cava contrast-to-noise ratio was 70.8 +/- 23.4, and inferior vena cava--to-aorta venous-to-arterial enhancement ratio was 0.03 +/- 0.04. No venous overlap was seen in 38 of 39 patients. Substantial enhancement of renal arteries was seen in all patients without any noticeable artifacts. MR angiography correctly depicted the degree of stenosis in 44 of 47 normal arteries, 13 of 16 mildly stenotic arteries, five of five moderately stenotic arteries, three of four severely stenotic arteries, and one of one occluded artery. Sensitivity and specificity for revealing greater than 50% stenosis was 100%. CONCLUSION: Time-resolved 3D MR angiography can provide high-quality arteriograms. Its performance in revealing renal artery stenosis is comparable with that of conventional angiography.

Dynamic MR dacryocystography: a new method for evaluating nasolacrimal duct obstructions.

OBJECTIVE: The purpose of this study was to evaluate the clinical performance of newly implemented dynamic MR dacryocystography. CONCLUSION: Dynamic MR dacryocystography, which requires neither ionizing radiation nor chemical contrast media with high viscosity, may be a useful tool for depicting nasolacrimal obstructions.

[Kinematic MRI using short TR single shot fast spin echo (SSFSE) in evaluating swallowing].

PURPOSE: To determine the utility of short TR single shot fast spin echo (SSFSE) MR imaging for evaluating swallowing. MATERIALS AND METHODS: Five healthy volunteers underwent kinematic MR imaging of swallowing with a 1.5T MR scanner using the short TR (300 ms) SSFSE sequence. Twenty phases of sagittal sections were acquired within 6 sec, where the temporal resolution was 300 ms. For oral contrast medium, we used prune yogurt juice with Fe added. RESULTS: The image contrast of short TR SSFSE was found to be somewhere like that of T1-weighted images. In all cases, both the buccal and pharyngeal stages of swallowing were successfully depicted. The Fe-added prune yogurt juice performed as a positive contrast medium and helped determine anatomical structures in the buccal stage. CONCLUSION: Short TR (300 ms) SSFSE was useful in evaluating swallowing. The combined use of Fe-added prune yogurt juice was helpful in enhancing the surface of the oropharynx.

[Dynamic magnetic resonance dacryocystography using half Fourier single shot fast spin echo sequence].

Dynamic magnetic resonance dacryocystography (MRD) was implemented using 1.5T superconductive imager with a standard head coil. Prior to MRD, a pair of polyethylene microcatheters were inserted into the lower lacrimal canaliculi. Injecting a mixture of 6 ml of saline and 4 ml of xylocaine (0.5%) as a substitute for contrast medium, repeated measurement of thick section heavily T2 weighted image using half Fourier single shot fast spin echo (SSFSE) sequence was performed. MRD could well depict the pathologies of the lacrimal sac and the lacrimal duct in five cases of epiphora. It pinpointed the level of lacrimal duct obstruction, which was confirmed by both X-ray dacryocystography and intraoperative findings. Dynamic MRD is a reliable method of diagnosing nasolacrimal duct obstruction without using ionizing radiation or chemical contrast medium.

Anterior extension of acute pancreatitis: CT findings.

OBJECTIVE: The purpose of this study is threefold: (a) to specify the pathway of the extension of pancreatitis to the anterior abdominal wall, which is clinically famous as the Cullen sign; (b) to assess if this pattern of involvement affects a patient's prognosis; and (c) to seek its association with the inflammatory processes that take place in the vicinity of the pancreatic head. MATERIALS AND METHODS: The CT findings of 277 patients with acute pancreatitis were retrospectively reviewed. RESULTS: Inflammatory changes involved the anterior abdominal wall in 5 of 277 cases (1.8%) with acute pancreatitis. Inflammatory processes seemed to have been delivered to the anterior abdominal wall from the pancreatic head and the hepatoduodenal ligament and along the falciform ligament. The probable triggers of acute pancreatitis in such cases were endoscopic retrograde cholangiopancreatography in two cases, alcohol intake in one case, and one case unknown. Three of five cases had proven or suspected choledocholithiasis or cholelithiasis. All five patients got well after proper treatments for acute pancreatitis. CONCLUSION: The results of our review suggest that the anterior extension of acute pancreatitis does not directly mean extensive retroperitoneal involvement of the phlegmon or pseudocysts nor fatal prognosis either and that this style of extension might be associated with inflammatory processes that occur around the pancreatic head.

[Enhanced delineation of the pancreatic duct in MR cholangiopancreatography (MRCP) with a combined use of secretin].

Magnetic resonance cholangiopancreatography (MRCP) is a method that can depict the main pancreatic duct non-invasively; however, its tendency to overestimate ductal stenosis is being noted. The authors used secretin to stimulate the output of pancreatic juice, which increased the signal of the main pancreatic duct and consequently minimized the occurrence of pseudostenosis artifacts in MRCP. MRCP images of 54 patients suspected of having pancreatic disease were visually evaluated by two observers before and after administration of secretin (1 clinical unit/kg). Improved delineation of the main pancreatic duct (68.5-59.3%, p < 0.05) and its side branches (40.7-29.6%, p < 0.05) was obtained with good interobserver agreement (kappa = 0.71-0.68).

Torsion of the wandering spleen: CT and angiographic appearance.

OBJECTIVE: To seek CT and angiographic appearances that characterize torsion of the wandering spleen. MATERIALS AND METHODS: The CT and angiographic findings of two cases of preoperatively diagnosed torsion of the wandering spleen were reviewed, and the findings were closely compared with intraoperative and histopathological findings. RESULTS: Characteristic CT appearance seemed to be a whirled appearance formed at the medial side of the displaced spleen. The angiographic finding that was characteristic of the disease was a tapered and abruptly twisted distal splenic artery. CONCLUSION: These findings were useful in making the early and correct diagnosis of this rare but fulminant condition.

Occlusion of the posterior humeral circumflex artery: detection with MR angiography in healthy volunteers and in a patient with quadrilateral space syndrome.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of MR angiography in detecting occlusion of the posterior humeral circumflex artery and to determine if the finding is specific for the diagnosis of quadrilateral space syndrome. SUBJECTS AND METHODS: Two-dimensional fast low-angle shot MR angiography was used to image both shoulders of one symptomatic patient and six asymptomatic volunteers (10 posterior humeral circumflex arteries). RESULTS: With the arm in a neutral position, the posterior humeral circumflex arteries appeared normal on MR angiograms of all subjects. However, when the arm was in abduction, occlusion of the posterior humeral circumflex artery was seen both in the symptomatic patient and in 80% of the asymptomatic volunteers. CONCLUSION: Our data show that occlusion of the posterior humeral circumflex artery is common in asymptomatic volunteers. Thus, MR angiography has no value in the diagnosis of quadrilateral space syndrome.

Breath-hold MR cholangiopancreatography with a long-echo-train fast spin-echo sequence and a surface coil in chronic pancreatitis.

PURPOSE: To assess heavily T2-weighted breath-hold magnetic resonance cholangiopancreatography (MRCP) for imaging the pancreatic duct in patients with chronic pancreatitis. MATERIALS AND METHODS: Thirty-nine patients with chronic pancreatitis were examined with a breath-hold fast spin-echo (FSE) sequence employing an echo train length of 32 and with a surface coil. Results were compared with those of endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: MRCP showed the head, body, and tail of the pancreatic duct well in 79%, 64%, and 53% of cases, respectively. Agreement between MRCP and ERCP was 83%-92% in cases of ductal dilatation, 70%-92% in cases of ductal narrowing, and 92%-100% in cases of filling defects. Interobserver variation was low (kappa > 0.5) for most findings. CONCLUSION: Breath-hold MRCP with an FSE technique depicts the pancreatic duct well in patients with chronic pancreatitis and demonstrates narrowing, dilatation, and filling defects with moderate to high accuracy.

[MR cisternography using "long echo train length fast spin echo sequence" for demonstrating the inner ear].

Excellent quality of MR cisternography was acquired using "long echo train length fast spin echo sequence" (TR/TE = 2666/200, ETL = 24, 6 or 8 NEX, 3 mm thickness, 0 mm interslice gap, 19 cm FOV, 512 * 384, 2 DFT method). The inner ear anatomy such as canaliculus cochleae or lamina spiralis ossea were well visualized. The VII, VIII th nerve bundles within the internal auditory canal were detectable as 1 to 4 bundles. The vessels in the cerebellopontine angle or the internal auditory canal were also demarcated from the VII, VIII th nerve bundles because of their flow void. Signal to noise ratio seemed to be better than 3 DFT method, however limited spatial resolution in the cranio-caudal direction might require additional sagittal or coronal scan.

[Breath hold MR cholangio-pancreatography (MRCP) using long echo train length fast spin echo sequence in combination with surface coil].

To test the feasibility of MR cholangio-pancreatography (MRCP) using long echo train length (32) fast spin echo sequence in combination with shoulder surface coil, 20 patients who had had ERCP were examined. Good correlations were acquired between the findings obtained by two modalities in terms of ductal strictures, dilatations and intraductal lesions. MRCP was considered to be an examination of choice in various kinds of pathologies affecting biliary duct as well as pancreatic duct for its non-invasiveness and reasonable image quality.