Hemorrhage owing to cerebral cavernous malformation: imaging, clinical, and histopathological considerations.

Cavernous malformation (CM) is the second most common cerebral vascular malformation and is often found incidentally. Their natural history is usually benign, however, patients with CM who present with symptomatic hemorrhage may later follow a serious clinical course if left untreated. The risk of hemorrhage is associated with previous hemorrhage, lesion location (infratentorial and deep), and the presence of associated developmental venous anomaly (DVA). Histopathological specimens also indicate that coexistence of DVA and other vascular malformations may be associated with hemorrhage owing to CMs. Diagnosing CMs is difficult, even in patients who initially present with symptomatic hemorrhage. Computed tomography scans typically reveal a hemorrhagic CM as a nonspecific heterogenous mass of high density, which may not be misdiagnosed as a solitary hematoma, especially when located in the infratentorial region. Magnetic resonance imaging demonstrates internal loculation with mixed-signal intensities typical for CMs, although this may be partially or completely masked by acute hemorrhage. Susceptibility-weighted imaging (SWI) reveals a significant "blooming" effect of hemosiderin deposition. Three-dimensional postcontrast T1-weighted imaging is essential to identify associated DVAs, and this is important for both diagnosis and planning of surgical treatment. Contrast-enhanced MRI should be performed to diagnose hemorrhagic CMs and differentiate them from spontaneous solitary hematoma or hemorrhagic tumors.

Nevus lipomatosus cutaneous superficialis on the shoulder: A case report with MRI findings.

Nevus lipomatosus cutaneous superficialis is a rare disease, and its magnetic resonance imaging features have not been reported. A 1-year-old male infant was admitted to our hospital for examination of a mass on his right shoulder. Magnetic resonance imaging revealed hypertrophic skin and a lipomatous subcutaneous mass, consistent with a hamartoma-like lesion or mesenchymal tumor; after surgery, the tumor was pathologically diagnosed as nevus lipomatosus cutaneous superficialis. To the best of our knowledge, this is the first case report focusing on the magnetic resonance imaging features of this disease. Hypertrophy of all skin structures involved (epidermis, dermis, and subcutaneous fat) may be specific to nevus lipomatosus cutaneous superficialis, enabling its differentiation from other tumors.

A Computed Tomographic Assessment of Tracheostomy Tube Placement in Patients with Chronic Neurological Disorders: The Prevention of Tracheoarterial Fistula.

Objective Tracheoarterial fistula (TAF) is a rare but devastating complication of tracheostomy caused by pressure necrosis from the elbow, tip, or over-inflated cuff of the tracheostomy tube. The incidence of TAF is reportedly higher in patients with neurological disorders than in those without such disorders. To evaluate the incidence of and factors contributing to the misalignment of tracheostomy tubes in bedridden patients with chronic neurological disorders. Methods We retrospectively assessed three-dimensionally reconstructed serial computed tomography (CT) images to see if the tip of the tube made contact with the tracheal wall and if the main arteries were running adjacent to the tube's elbow, tip or cuff. Results The tip of the tube was in contact with the tracheal wall in 14 of the 30 patients assessed. Among them, the tip was adjacent to the innominate artery in eight, the aortic arch in three and an aberrant right subclavian artery in one. In one patient with the tube tip adjacent to the aortic arch and the other four patients, the cuff of the tube was adjacent to the innominate artery across the tracheal wall. Patients with the tube tip in contact with the anterior tracheal wall had a significantly greater cervical lordosis angle than those without contact (p<0.05). Conclusion More than half of tracheostomized patients with chronic neurological disorders had a latent risk of TAF. The variability in the location of the innominate artery, anomalies of the aortic arch, and skeletal deformities may therefore be contributing factors.

Mitochondrial Cardiomyopathy with a Unique 99mTc-MIBI/123I-BMIPP Mismatch Pattern.

A 42-year-old man was referred to our hospital due to chest pain, diabetes mellitus, and sensorineural hearing loss. Transthoracic echocardiography revealed diffuse left ventricular hypokinesis. He was diagnosed with mitochondrial disease and a c.A3243G mutation was identified in his mitochondrial DNA. This case of mitochondrial cardiomyopathy demonstrated a low uptake of 123I-BMIPP, while the uptake of 99mTc-MIBI was preserved. In contrast, previous reports have noted the increased uptake of123I-BMIPP and the decreased uptake of 99mTc-MIBI. This is the first study to show this unique 99mTc-MIBI/123I-BMIPP mismatch pattern. We also discuss the relationships among the cardiac scintigraphy, cardiac magnetic resonance imaging, and histopathology findings.

Spontaneous retroperitoneal hemorrhage caused by rupture of an ovarian artery aneurysm: a case report and review of the literature.

INTRODUCTION: Spontaneous rupture of an ovarian artery aneurysm is extremely rare. Although a majority of these cases have been associated with pregnancy, there have been recent reports and reviews of rare cases that were not directly associated with pregnancy. Transcatheter arterial embolization is considered to be an alternative therapy to surgery. CASE PRESENTATION: A 44-year-old Japanese woman, gravida 3 para 3, presented to our emergency room complaining of intermittent right flank pain. She had undergone a cesarean section 2 years previously, and had no history of abdominal trauma. On admission, her blood pressure was 115/78 mmHg, pulse 70 beats per minute, and hemoglobin concentration 9.8 g/dL. Abdominal ultrasonography and contrast-enhanced dynamic computed tomography revealed a large retroperitoneal hematoma. Findings on three-dimensional computed tomography angiography suggested ruptured aneurysm of her right ovarian artery. A selective right ovarian artery angiogram revealed a tortuous aneurysm. Transcatheter arterial embolization using N-butyl-2-cyanoacrylate was performed. The aneurysm was successfully embolized, and her course after embolization was uneventful. She has remained symptom-free during 3 months of follow-up. CONCLUSIONS: This was a very rare case of a patient who had a retroperitoneal hemorrhage originating from an ovarian artery aneurysm. A review of published case reports found that contrast-enhanced computed tomography with reconstruction images is an excellent imaging tool. Diagnostic angiography and subsequent transcatheter arterial embolization are thought to be very effective for this condition.

A case report of segmental arterial mediolysis in which computed tomography angiography was useful for diagnosis.

A 48-year-old male presented to our hospital with abdominal pain. Laboratory studies showed no abnormality, the severity of his abdominal pain decreased, and the patient was discharged. Five days later, the patient visited a neighborhood clinic because of fever with a 3-day history of temperatures of approximately 38 °C. The patient was admitted to our hospital 6 days after his initial visit. Laboratory investigation revealed a C-reactive protein level of 18.2 mg/dL. Abdominal computed tomography (CT) showed an 80 × 60 mm hematoma behind the descending colon, but no extravasation was detected. Thin-slice maximum-intensity-projection images from CT angiography (CTA) showed irregular narrowing and intermittent fusiform dilatations of the left colonic artery, suggesting a vascular disease, such as segmental arterial mediolysis (SAM). Digital subtraction angiography showed local irregularity, and 'beading and narrowing' of the left colonic artery, similar to the findings on CTA. Left hemicolectomy was electively performed on the twenty-fifth hospital day. Histological findings were consistent with SAM. Thus, CTA was a useful modality for the early diagnosis of SAM.

Lipomatous hypertrophy of the interatrial septum with cutaneous lipomatosis.

A mass was identified in the atrial septum by clinical imaging in a patient who had multiple large lipomas of the skin. Multislice computed tomography and magnetic resonance imaging indicated that the interatrial mass was a fatty infiltration. In order to discriminate the myocardial lesion from myxoma and other benign conditions and malignant tumors, percutaneous transvenous biopsy was performed. Microscopic examination demonstrated the cardiac mass to be lipomatous hypertrophy of the interatrial septum (LHIS), and the skin lesions, simple lipomas. The LHIS is itself a rare condition, and its development in patients having multiple ponderous lipomas, or lipomatosis, could not be found in a previous report. This may be the first published case of LHIS, which likely represents cardiac involvement of lipomatosis.

Quantitative vascular measurements in arterial occlusive disease.

Accuracy in quantifying arterial occlusive disease requires an understanding of the relevant technical considerations and familiarity with the strengths and weaknesses of various imaging modalities in this setting. The degree of stenosis is evaluated in terms of diameter stenosis, which can be measured on either projection images or cross-sectional images, or area stenosis, which can be measured only on cross-sectional images. With projection images, the minimum luminal diameter should be sought on multiple images obtained at different angles. The reference site used for measurement should be noted and may be located at the level of the lesion or in a normal-looking portion of the stenotic vessel near the lesion. Multi-detector row computed tomographic (CT) angiography and magnetic resonance (MR) angiography are starting to replace digital subtraction angiography in quantifying arterial occlusive disease. CT angiography allows accurate evaluation without reducing in-plane resolution, although beam-hardening artifacts from high-attenuation structures can degrade image quality. MR angiography is useful even in cases of severe calcification but has a lower spatial resolution. Ultrasonography (US) may also be helpful in quantifying arterial occlusive disease; US analysis is almost always based on blood flow velocity measurement. Precise measurements of stenotic occlusion will help determine optimal therapy for affected patients.

Time-related changes of radiofrequency ablation lesion in the normal rabbit liver: findings of magnetic resonance imaging and histopathology.

RATIONALE AND OBJECTIVES: To study time-related magnetic resonance imaging (MRI) and histopathological findings after radiofrequency ablation (RFA) in the normal liver. METHODS: Under ultrasound guidance, RFA was performed in 22 rabbits with a 15-gauge expandable probe inserted into the liver. The RF power was applied at 10 W initially with a 5-W increment every minute until RF power "roll-off" occurred. The rabbits subjected to postmortem MRI at 3 days (n = 6), 2 weeks (n = 6), 4 weeks (n = 6), and 12 weeks (n = 4) after RFA. Spin-echo (SE) T(1)-weighted image (WI) (TR/TE=500/12) and fast SE T2-WI (TR/TE= 3500/99) were obtained. The liver specimens were excised and processed for conventional histologic study. The MRI and pathologic findings were compared qualitatively and quantitatively. RESULTS: The lesion diameters measured with MRI and liver specimen were well correlated (P < 0.05). The coagulated regions presented 2 of 4 laminar patterns on T1/T2-WI 3 days after RFA, and 2 of 3 laminar patterns on T1/T2-WI 2 to 4 weeks after RFA. 12 weeks after RFA, the signal intensity in coagulated regions increased on T1-WI with a 2-laminar pattern still visible on T2-WI, the same as that of 2 to 4 weeks. The observed pathologic changes (enlarged sinusoids, marginal fibrous tissue and hepatocyte degeneration) could be responsible for the MRI laminar patterns and signal intensity changes. CONCLUSION: The time-related pathologic changes of RFA lesions in rabbit livers can be reflected as laminar patterns on MR images. Understanding of the zone structure of the lesions is useful for the evaluation of follow-up MRI.