Diffusion-weighted echo-planar imaging of the head and neck using 3-T MRI: Investigation into the usefulness of liquid perfluorocarbon pads and choice of optimal fat suppression method.

PURPOSE: To investigate whether image quality can be improved using liquid perfluorocarbon pads (Sat Pad) and clarify the optimal fat-suppression method among chemical shift selective (CHESS), water excitation (WEX), and short TI inversion recovery (STIR) methods in diffusion-weighted imaging (DWI) of the head and neck using 3-T magnetic resonance imaging. Correlations between results of visual inspection and quantitative analysis were also examined. MATERIAL AND METHODS: This study was approved by our Institutional Review Board and informed consent was waived. DWI was performed on 25 subjects with/without Sat Pad and using three fat-suppression methods (6 patterns). Image quality was evaluated visually (4-point scales and lesion-depiction capability) and by quantitative analysis (signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)). Two-way repeated-measures analysis of variance (ANOVA) was used to detect significant differences in scores of visual evaluation, SNR, and CNR. RESULTS: Mean visual evaluation scores were significantly higher with Sat Pad using STIR than without Sat Pad for all fat-suppression methods (P<0.05). DWI with Sat Pad using STIR tended to be useful for depicting lesions. DWI using STIR showed reduced W-SNR (W: whole area of depicted structure) and CNR (between semispinalis capitis muscle and subcutaneous fat) due to fewer artifacts and uniform fat suppression. CONCLUSION: Combining Sat Pad with STIR provides good image quality for visual inspections. When numerous artifacts are present and fat suppression is insufficient, higher SNR and CNR do not always provide good diagnostic image quality.

Usefulness of Tc-99m-GSA scintigraphy for liver surgery.

Postoperative mortality remains high after hepatectomy compared with other types of surgery in patients who have cirrhosis or chronic hepatitis. Although there are several useful perioperative indicators of liver dysfunction, no standard markers are available to predict postoperative liver failure in patients with hepatocellular carcinoma (HCC) undergoing hepatectomy. The best preoperative method for evaluating the hepatic functional reserve of patients with HCC remains unclear, but technetium-99m diethylenetriamine pentaacetic acid galactosyl human serum albumin ((99m)Tc-GSA) scintigraphy is a candidate. (99m)Tc-GSA is a liver scintigraphy agent that binds to the asialoglycoprotein receptor, and can be used to assess the functional hepatocyte mass and thus determine the hepatic functional reserve in various physiological and pathological states. The maximum removal rate of (99m) Tc-GSA (GSA-Rmax) calculated by using a radiopharmacokinetic model is correlated with the severity of liver disease. There is also a significant difference of GSA-Rmax between patients with chronic hepatitis and persons with normal liver function. Regeneration of the remnant liver and recurrence of hepatitis C virus infection in the donor organ after living donor liver transplantation have also been investigated by (99m)Tc-GSA scintigraphy. This review discusses the usefulness of (99m)Tc-GSA scintigraphy for liver surgery.

Efficacy of clonidine in patients with essential hypertension with neurovascular contact of the rostral ventrolateral medulla.

The rostral ventrolateral medulla (RVLM) is an important center for regulation of sympathetic nerve activity. Several clinical studies have suggested an association between neurovascular contact (NVC) of RVLM and essential hypertension. Microvascular decompression (MVD) of RVLM decreases blood pressure (BP) in hypertensive patients with NVC of this region. Therefore, MVD could be a useful therapeutic strategy to reduce BP in these patients. However, as MVD is an invasive procedure, it is worthy to seek useful antihypertensive agents for hypertensive patients with NVC. It is reported that sympathetic nerve activity is elevated in patients with hypertension accompanied by NVC of RVLM. It is anticipated that sympatholytic agents could be effective in lowering BP in these patients. In this study, we investigated the efficacy of clonidine, an alpha2 adrenergic agonist, in essential hypertensives with NVC of RVLM. Thirty consecutive essential hypertensive patients with NVC and 30 consecutive essential hypertensive patients without contact were treated with clonidine for 4 weeks, and decreases in BP and plasma norepinephrine levels were compared between the two groups. Decreases in BP and plasma norepinephrine levels were significantly greater in patients with NVC than in those without contact. These results suggest that clonidine exhibits significantly greater reductions of BP and sympathetic nerve activity in essential hypertensive patients with NVC compared with those without contact of the rostral ventrolateral medulla.

Efficacy of an L- and N-type calcium channel blocker in hypertensive patients with neurovascular compression of the rostral ventrolateral medulla.

The rostral ventrolateral medulla is an important regulation center of sympathetic nerve activity. Several clinical studies have indicated a possible association between essential hypertension and neurovascular compression of the rostral ventrolateral medulla. We have found that patients with essential hypertension and neurovascular compression of the rostral ventrolateral medulla by adjacent arteries have increased sympathetic nerve activity and that microvascular decompression of the rostral ventrolateral medulla normalizes blood pressure and sympathetic nerve activity. Although sympatholytic agents are expected to lower blood pressure in these patients, this remains to be clarified. In this study, we evaluated the effect of cilnidipine, a calcium channel blocker that blocks both vascular L-type and sympathetic N-type Ca(2+) channels in hypertensive patients with neurovascular compression. Using high-resolution magnetic resonance imaging, 46 patients with untreated essential hypertension were distributed into those with and without neurovascular compression of the rostral ventrolateral medulla. All patients were prescribed 10 mg of cilnidipine for 16 weeks. Office and home blood pressure, plasma norepinephrine and left ventricular mass index were measured by echocardiography before and after cilnidipine treatment, and changes were compared between the two groups. At baseline, plasma norepinephrine was significantly higher in patients with neurovascular compression. Decreases in office and home blood pressure, plasma norepinephrine and left ventricular mass index were significantly greater in patients with neurovascular compression. These results suggest that cilnidipine lowers blood pressure by inhibiting enhanced sympathetic nerve activity and reduces left ventricular mass in hypertensive patients with neurovascular compression of the rostral ventrolateral medulla.

Traumatic neuroma of the bile duct.

We present the CT and MRI findings of a traumatic neuroma of the bile duct, which is not a true neoplasm, but a reactive proliferation of pericholangial nerve tissue induced by cholecystectomy. Previous authors have shown a dilatation of the bile duct without a nodule. In our case, a nodule was present, and it was markedly enhanced.

Corpus callosum in patients with obsessive-compulsive disorder: diffusion-tensor imaging study.

PURPOSE: To prospectively examine microstructural white matter abnormalities in the corpus callosum (CC) of patients with obsessive-compulsive disorder (OCD), as compared with control subjects, and to investigate the relationship between diffusion-tensor (DT) imaging measures of the CC region and clinical symptoms of OCD. MATERIALS AND METHODS: Institutional review board approval was obtained, and each participant--or the participant's parent(s)--provided written informed consent. Sixteen patients with OCD (seven male, nine female; mean age, 28.7 years +/- 9.8 [standard deviation]) and 16 matched healthy volunteers (control subjects) (seven male, nine female; mean age, 29.9 years +/- 9.0) were examined. Mean diffusivity and fractional anisotropy (FA) were measured in five subdivisions of the CC. The paired t test was performed to compare the mean diffusivity or the FA in CC regions between the patients with OCD and the control subjects. RESULTS: There were no significant differences (rostrum, P = .15; genu, P = .88; rostral body, P = .12; isthmus, P = .77; splenium, P = .88) in mean diffusivity between the patients with OCD and the healthy volunteers. A significant reduction in FA was observed in the rostrum of the CC in patients with OCD compared with the rostral FA in the control subjects (P < .001). Higher FA in only the rostrum correlated significantly with lower Yale-Brown obsessive-compulsive scale score (r = -0.72, P = .002). CONCLUSION: Study results support the widely held view that the orbital prefrontal region is involved in the pathophysiology of OCD and indicate that the orbitofrontal circuit influences symptom severity in patients with OCD.

Hourglass-shaped sublingual dermoid cyst: MRI features.

Dermoid cysts located in the floor of the mouth are classified as submental or sublingual based on their location with respect to the mylohyoid muscle. The lesion was located in the midline, involved the genioglossus and geniohyoid muscles, and extended down to the area superior to the mylohyoid muscle. An hourglass-shaped cyst of the floor of mouth was seen. Such magnetic resonance imaging findings appear to be characteristic of an extended sublingual dermoid cyst.

Leiomyoma of the trachea: CT and MRI findings.

A 47-year-old woman with a tracheal leiomyoma is described. Leiomyoma is a rare benign tumor of the trachea. Only 43 cases have been reported in the English- and Japanese-language literature. To our knowledge, this is the second time magnetic resonance imaging (MRI) findings have been reported. MRI can help discriminate between masses with a stalk and masses with a broad base, which in turn can help determine whether surgical resection of the tracheal leiomyoma is appropriate.

Spontaneous rupture of a necrotic hepatic angiosarcoma: findings on dual-phase computed tomography and angiography.

We present dual-phase computed tomographic (CT) and angiographic findings of a ruptured hepatic angiosarcoma. These tumors can be divided into two types: those with and those without gross central necrosis with hemorrhage. In our case, the tumor had gross central necrosis, and CT and angiographic findings showed a small number of areas with a centripetal enhancement pattern and the rest of the tumor with avascular areas. We found that dual-phase CT and angiographic findings are able to distinguish angiosarcoma, which mimics a hemangioma, as these lesions show avascular areas that reflect a mass with gross central necrosis.

Non-necrotic invasive squamous cell carcinoma associated with an inverted papilloma: MRI features.

We present the MRI findings of a carcinoma associated with an inverted papilloma located in the nasal cavity. This tumor can be divided into 2 types, those with and those without gross central necrosis. In our case, the tumor did not have any gross central necrosis, and MRI showed convoluted cerebriform patterns. We found that MRI is unable to distinguish malignant and benign regions in a central mass with no gross necrosis, since this lesion does not alter the basic morphological pattern of inverted papilloma.

Cellular leiomyoma of the nasal cavity: findings of CT and MR imaging.

Nasal leiomyoma, a benign tumor composed of smooth muscle cells, is rare in the head and neck region. Cellular leiomyomas of the uterus exhibit high intensity on T2-weighted images. Here we present a case of nasal leiomyoma in which the pathologic findings are similar to those of cellular leiomyoma. The present case exhibited slightly elevated intensity on T2-weighted images and marked enhancement on postcontrast images. CT findings showed a soft tissue lesion without bone erosion. These findings appear to be characteristic of intranasal leiomyoma.

Multislice computed tomography of pneumoparotid: a case report.

Pneumoparotid is a rare cause of parotid gland swelling that is often misdiagnosed and therefore incorrectly treated. It is the result of an increase in intraoral pressure and the subsequent forced entry of air through Stensen's duct. We report a case of a 15-year-old boy with a history of recurrent swelling of both parotid glands. The final diagnosis of pneumoparotid was established by multislice computed tomography (CT). The clinical presentation, pathogenesis, and radiographic findings are discussed.