Biomedical subjects
Publications and source records attributed to K Yoshimitsu.
A case of primary lymphoma in the porta hepatis is presented here. Cholangiography, angiography, ultrasonography and computed tomography suggested the presence of a mass in the porta hepatis, but all these failed to demonstrate the tumor clearly. Magnetic resonance imaging was very useful in defining the characteristics of the tumor and in delineating its extent, though it was not specifically diagnostic.
BACKGROUND: To compare the value of helical computed tomography (CT) and various pulse sequences of magnetic resonance (MR) imaging in the detection and staging of small pancreatic adenocarcinoma. METHODS: Small pancreatic adenocarcinomas (< or = 2 cm in diameter) in eight patients were evaluated with both helical CT and MR imaging. Five MR imaging pulse sequences that included fat-suppressed T1-weighted images and dynamic study using fast multiplanar spoiled gradient-recalled technique were compared for the tumor detectability. To evaluate the tumor vascularity, angiographic findings were also investigated. RESULTS: Helical CT delineated the tumor in five cases, and MR imaging depicted the tumor in seven cases. MR imaging could detect the tumor of 0.8 cm in diameter clearly. Although helical CT and dynamic MR imaging missed the tumor of 2 cm with relative hypervascularity, fat-suppressed T1-weighted MR imaging demonstrated it precisely. As for the tumor staging, MR imaging was equal or slightly superior to helical CT. CONCLUSION: MR imaging is the first modality of choice to evaluate small pancreatic adenocarcinoma, and fat-suppressed T1-weighted images and dynamic study must be performed.
A case of uterine lipoleiomyoma demonstrated on computed tomography (CT) and magnetic resonance imaging (MRI) is described and usefulness of MRI is discussed in diagnosing this entity.
We report a case of a chronic expanding hematoma caused by an angiomyolipoma of the spleen in a patient diagnosed with tuberous sclerosis in infancy. Computed tomography showed large bilateral renal angiomyolipomas. A splenic mass that increased in size during the follow-up period of 62 months was also noted. A large subcapsular hematoma of the spleen finally developed, and a splenectomy was performed. The splenic mass consisted of a chronic hematoma with prominent granulation tissue, which was considered to be caused by repeated bleeding from a small angiomyolipoma in the spleen.
A rare case with a pseudolesion in segment II of the liver observed on computed tomography (CT) during arterial portography caused by the aberrant left gastric venous drainage is presented. Close observation of the celiac angiography was helpful in recognizing this pseudolesion. Selective catheterization of the left gastric artery and CT during its venous phase confirmed the etiology of the pseudolesion.
Preoperative chemical-shift magnetic resonance images in a 56-year-old man suggested the presence of microscopic fat in the tumor. The surgical specimen showed a granular-cell renal cell carcinoma with papillary architecture, associated with abundant fat-containing foamy histiocytes in the interstitium. The radiologist should include this entity in the differential diagnoses of renal tumors that contain microscopic fat.
A port-catheter system was implanted via femoral artery access for hepatic artery chemotherapy infusion. Implantation was attempted in 90 patients and was successful in 88. Blood flow redistribution was performed using embolization coils. In the first ten patients a soft heparin-coated infusion catheter was used. For the following 78 patients we used a stiffer catheter coated with fluorine-acryl-styrene-urethane-silicone (FASUS) copolymer. The catheter was connected to a port implanted subcutaneously below the level of the inguinal ligament. Complications during the procedure and after placement were observed in 7 of 90 patients and 24 of 88 patients, respectively. These included catheter obstruction (11%), dislocation of the catheter tip (10%), drug toxicity (5.7%), and catheter infection (3.4%). In 6 of 10 patients with catheter obstruction, recanalization of the port system was achieved. In 7 of 9 patients with dislocation of the indwelling catheter tip, replacement of the port system was successful. Our complications appear to be comparable with those encountered with the subclavian/brachial approach when the new catheter coating is used. Notable is the avoidance of cerebral infarcts.
A 43-year-old non-cirrhotic woman suffered from encephalopathy caused by an extrahepatic portosystemic shunt between the ileal vein and inferior vena cava via the right gonadal vein. Percutaneous transcatheter embolization with stainless steel coils was performed by the retrograde systemic venous approach. Encephalopathy improved dramatically.
A 34-yr-old man with a liver mass was referred to the hospital. The mass showed temporary spontaneous regression during the follow-up, however, subsequent regrowth of the tumor prompted surgical resection. The specimen revealed intrahepatic cholangiocarcinoma with two distinct components which had been clearly demonstrated on serial CT. Spontaneous resolution of a lesion does not necessarily suggest the lesion's benign, self-limiting entity. Intrahepatic cholangiocarcinoma should be included in the tumors that could spontaneously regress.
We describe the computed tomography (CT) appearance of an unusual, large retroperitoneal granular cell tumor and provide a 5-year follow-up. The tumor occurred in association with multiple, smaller, subcutaneous granular cell tumors. The CT findings were nonspecific, but the scans delineated the extent of the lesion and its relationship to adjacent vessels well. To our knowledge, this report is the first description of the CT appearance of retroperitoneal granular cell tumor in the medical literature.
A rare case with a large pseudolesion in the left lobe of the liver observed on early phase of incremental dynamic computed tomography (CT) caused by inferior vena caval obstruction is presented. Decreased portal perfusion due to increased volume of systemic venous inflow into the left lobe via paraumbilical venous system may be its underlying hemodynamic change. The etiology of this pseudolesion was successfully confirmed by conventional CT with intravenous contrast medium injection via superficial vein of lower extremity.
A case with a pseudolesion associated with focal fatty deposition in segment IV of the liver observed on conventional CT and CT during arterial portography caused by the parabiliary venous drainage is presented. Close observation of the common hepatic angiography was helpful to recognize this unusual vessel as a cause of this pseudolesion. Selective catheterization of the posterior superior pancreaticoduodenal artery and CT during its venous phase confirmed the etiology of the pseudolesion.
We report a rare case of iatrogenic arterial dissection of the superior mesenteric artery (SMA) during diagnostic angiography. A conventional superior mesenteric arteriogram obtained using an automated power injector revealed an arterial dissection 2s after the initiation of contrast-medium injection. This case indicates that although careful catheter manipulations during angiography are essential, certain unavoidable complications may occur.
A rare case of transitional cell carcinoma (TCC) with extension into the renal vein and inferior vena cava (IVC) is presented. Computed tomography, magnetic resonance imaging, and angiography successfully delineated tumor thrombus in the right renal vein and IVC. TCC should be included in the differential diagnosis of renal tumors that can cause IVC thrombosis.
A case of radiologically identified molar invasion into extensive arteriovenous shunts (AVSs) is described. CT and MRI revealed a large uterine mass, accompanied by multiple AVSs. Dynamic MRI and pelvic angiography demonstrated multiple trophoblastic cysts invading into the AVSs. Resected specimen confirmed the diagnosis of invasive mole. Dynamic MRI was very useful in determining the etiology of AVS.
To compare the diagnostic efficacy of three-dimensional fast imaging with steady precession (3D-FISP) dynamic MR imaging in assessing pancreatic ductal adenocarcinoma with conventional MR imaging and helical CT, 15 patients with surgically proven pancreatic ductal adenocarcinoma were studied. Contrast-to-noise ratio (CNR) of the tumor, tumor detectability, local tumor extension, and vascular involvement were evaluated for all techniques. The results indicate that 3D-FISP dynamic MR imaging may improve the imaging assessment of pancreatic ductal adenocarcinoma.
A case of ileoileocolic intussusception caused by an ileal lipoma is presented, in which CT revealed the characteristic double layer of mesenteric fat and a lipoma as the leading mass.
OBJECTIVE: Our goal was to elucidate the CT and MRI findings of inflammatory pseudotumors of the spleen. METHODS: The CT and MRI findings of three patients with inflammatory pseudotumors of the spleen were reviewed and compared with the pathologic findings. RESULTS: On the early phase of CT, the masses were hypodense to the normal spleen, and on the delayed phase, they demonstrated delayed enhancement. On T1-weighted MR images, the masses were isointense to the normal spleen, and on T2-weighted images, the masses had heterogeneous low signal intensities. After administration of Gd-DTPA, the masses showed delayed enhancement. CONCLUSION: Inflammatory pseudotumors of the spleen were characterized by low signal intensity on T2-weighted MR images and delayed enhancement after contrast material administration on CT and MRI. The fibrous stroma may contribute to these unusual findings.