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Biomedical subjects

Junji Konishi

Publications and source records attributed to Junji Konishi.

At least 55 records · Page 3Linked to original sources
PubMed2003

[Cardiac imaging including nuclear medicine, MRI, and MDCT].

Nuclear cardiology has played a significant role in the diagnosis and risk stratification of patients with coronary artery disease. MRI and multidector-row CT (MDCT) has recently been introduced in the field of clinical cardiology. For the management of patients with suspected coronary artery disease, it is important to understand the advantages and disadvantages of various imaging modalities. This review discusses the current roles and problems of these imaging modalities.

Acute Disease↗
PubMed2002

Adnexal masses caused by pelvic inflammatory disease: MR appearance.

PURPOSE: To describe the morphologic and signal intensity characteristics of inflammatory adnexal masses in magnetic resonance (MR) images. MATERIALS AND METHODS: MR images of 15 patients with a total of 20 confirmed inflammatory adnexal masses were analyzed retrospectively. RESULTS: The findings obtained from MR imaging were as follows: lesions have ill-defined borders; ill-defined areas of high intensity signals surround the masses on T(2)-weighted images; a "rim" at the innermost layer of the cyst wall exhibits high signal intensity on T(1)-weighted images and low intensity on T(2)-weighted images; secondary changes in the surrounding fat plane and bowel loops are extensive; and adhesions are dense. These findings reflect the basic characteristics of the inflammatory process, which are edema caused by increased permeability and highly vascularized granulation tissue caused by the strong tendency to repair. CONCLUSION: MR imaging findings well reflect the basic pathological process of inflammation, and inflammatory adnexal masses are associated with relatively specific appearances in MR images. MR imaging can be a problem-solving alternative in the diagnosis of inflammatory adnexal masses.

Adnexal Diseases↗
PubMed2002

MR imaging with quantitative diffusion mapping of tacrolimus-induced neurotoxicity in organ transplant patients.

Our objective was to investigate brain MR imaging findings and the utility of diffusion-weighted (DW) imaging in organ transplant patients who developed neurologic symptoms during tacrolimus therapy. Brain MR studies, including DW imaging, were prospectively performed in 14 organ transplant patients receiving tacrolimus who developed neurologic complications. In each patient who had abnormalities on the initial MR study, a follow-up MR study was performed 1 month later. Apparent diffusion coefficient (ADC) values on the initial MR study were correlated with reversibility of the lesions. Of the 14 patients, 5 (35.7%) had white matter abnormalities, 1 (7.1%) had putaminal hemorrhage, and 8 (57.1%) had normal findings on initial MR images. Among the 5 patients with white matter abnormalities, 4 patients (80.0%) showed higher than normal ADC values on initial MR images, and all showed complete resolution on follow-up images. The remaining 1 patient (20.0%) showed lower than normal ADC value and showed incomplete resolution with cortical laminar necrosis. Diffusion-weighted imaging may be useful in predicting the outcomes of the lesions of tacrolimus-induced neurotoxicity.

Adult↗
PubMed2002

Immature teratoma of the ovary: correlation of MR imaging and pathologic findings.

The objectives of this study were to describe MR imaging findings of immature teratoma and to correlate imaging findings with histopathologic findings. The MR findings of ten patients (age range 12-29 years, mean age 19.0 years) with pathologically proven immature teratoma were retrospectively reviewed for tumor size, presence and characteristics of fatty content, presence and characteristics of solid components, and presence of ascites and implants. The MR findings were compared with gross (n=3) and microscopic (n=10) findings. Comparisons between relative amounts of solid components and histologic grades were evaluated by Spearman rank-order correlation. On MR images all lesions appeared to be fat-containing tumors with solid components consisting of numerous cysts of various sizes. Solid tissue exhibited a wide variety of signal intensities on T2-weighted images. Punctate foci of fat were identified in all lesions, whereas fatty fluid was observed only in two. Predominant fluid content exhibited signal intensities similar to simple fluid in nine lesions. Ascites was observed in six lesions, and peritoneal dissemination in three. Pathologic studies confirmed scattered foci of adipose tissue in the solid portions of all cases, and revealed numerous cystic structure formations in these solid components. The correlation coefficient between the amount of solid tissue and the tumor grade was not significant (r(s)=0.266). The MR images of immature teratoma tended to show aqueous fluids and the solid components consisting of numerous cysts with punctate foci of adipose tissue, whereas predominant fluid is sebaceous fluid in the vast majority of mature cystic teratomas.

Adolescent↗
PubMed2002

Transcatheter microcoil embolotherapy for ruptured pseudoaneurysm following pancreatic and biliary surgery.

PURPOSE: To evaluate the outcome of transcatheter microcoil embolotherapy for bleeding pseudoaneurysms complicating major pancreatic and biliary surgery. MATERIALS AND METHODS: Over an 8-year period, 8 patients were encountered who developed massive bleeding from pseudoaneurysms 15-64 days (mean 31 days) following major pancreatic and biliary surgery. Urgent transcatheter microcoil embolotherapy was performed in all 8 patients. RESULTS: Transcatheter embolotherapy was successful in 7 of 8 patients (88%) but failed in one due to development of disseminated intravascular coagulation. One patient developed recurrent bleeding 36 days after the first embolotherapy from a newly developed pseudoaneurysm, which was again treated successfully with embolization. Two patients subsequently underwent additional surgery for residual pathology. Three of the 7 patients with successful embolotherapy were alive at 10-96 months, 4 patients died of associated malignancies 4-20 months after embolotherapy. CONCLUSION: Transcatheter microcoil embolotherapy is effective for bleeding pseudoaneurysms complicating pancreatic and biliary surgery, and should be considered the first treatment of choice.

Aged↗
PubMed2002

An unusual presentation of endometrial polyp.

A 33-year-old woman was incidentally found to have a polypoid adenofibroma on MR imaging during the evaluation of carcinoma in situ of the cervix. The position of the polypoid lesion was variable from time to time. Although the lesion was a benign pedunculated one, T2-weighted MR images showed disruption of "junctional zone" in the posterior myometrial wall of the uterus, mimicking myometrial invasion of endometrial carcinoma.

Adenofibroma↗
PubMed2002

Efficacy of nonsurgical treatments for hepatocellular carcinoma in the caudate lobe.

PURPOSE: To evaluate the efficacy of nonsurgical treatments for caudate hepatocellular carcinoma (HCC). METHODS: Between January 1994 and February 2001, 25 patients were treated for HCCs with percutaneous ethanol injection (PEI), and/or transcatheter arterial embolization (TAE). PEI was performed for 19 caudate HCCs, combined treatment with PEI and TAE for 4 nodules, and TAE for 2 nodules. RESULTS: During follow-up periods ranging from 3 to 60 months (mean 21.3 months), 18 patients had no local recurrence. Local recurrence was seen in 7 patients, and recurrence in the other segments of the liver in 15 patients. Thirteen patients were alive, ranging from 6 to 60 months, and 12 patients died of multiple HCCs, hepatic failure, or rupture of esophageal varix. The 1-, 2-, 3-, and 5-year survival rates of the 25 patients were 70.6%, 60.2%, 48.1%, and 16.0%, respectively. CONCLUSION: PEI, PEI and TAE, or TAE would be an effective alternative treatment for HCC in the caudate lobe.

Aged↗
PubMed2002

Rapid accumulation and internalization of radiolabeled herceptin in an inflammatory breast cancer xenograft with vasculogenic mimicry predicted by the contrast-enhanced dynamic MRI with the macromolecular contrast agent G6-(1B4M-Gd)(256).

The rapid blood flow and perfusion of macromolecules in the inflammatory breast cancer xenograft (WIBC-9), which exhibits a "vasculogenic mimicry" type of angiogenesis without the participation of endothelial cells and expresses high levels of the HER-2/neu antigen, was evaluated in mice using 3D-micro-MR angiography using a novel macromolecular MR contrast agent [G6-(1B4M-Gd)(256)]. Herceptin, which recognizes the HER-2/neu antigen and has similar size (10 nm) to G6-(1B4M-Gd)(256), accumulated and internalized in the WIBC-9 tumors more quickly than in the control MC-5 tumors that progress with normal angiogenesis. Three dimensional micro-MRI with the G6-(1B4M-Gd)(256) macromolecular MRI contrast agent distinguishes between the different types of angiogenesis and is predictive of the rapid accumulation and internalization of Herceptin in the WIBC-9 inflammatory breast cancer xenograft.

Animals↗
PubMed2002

A patient with two thyroid papillary carcinomas demonstrating hot and cold lesions on 113I thyroid scintigraphy.

A 44-year-old euthyroid woman had two palpable nodules in the thyroid gland. 123I thyroid scintigraphy showed a hot nodule in the right lobe and a cold one in the left lobe. Total thyroidectomy was performed, and histopathologic examination revealed that both tumors contained papillary carcinoma. Thus, hot nodules on a thyroid scintigram with 123I do not necessarily preclude malignancy.

Adult↗
PubMed2002

Chemo-radionuclide therapy for thyroid cancer: initial experimental study with cultured cells.

UNLABELLED: Radioiodine therapy has long been used for distant metastases of thyroid cancer. Although partially effective in most cases, it can render a complete cure only in a limited number of patients. One way to enhance its efficacy would be to combine it with antineoplastic agents. Here we describe an initial in vitro evaluation with 4 thyroid cancer cell lines. METHODS: Cells were sparsely seeded in microtiter plates and allowed to grow for 2 days; then they were exposed to sublethal concentrations of cisplatin (CDDP), doxorubicin (Dox), or 5-fluorouracil (5-FU), followed by treatment with I-131 for 48 hr. Cell survival was measured with a commercial kit based on the colorimetry of succinate dehydrogenase activity. RESULTS: Chemotherapeutic drugs exerted similar concentration-dependent cytotoxic effects in all 4 cell lines. The doses necessary to reduce the surviving fraction to half of the control were about 3 microg/ml for CDDP, 0.3 microg/ml for Dox, and 3 microg/ml for 5-FU (when used continuously for 48 hours). On the other hand, sensitivity to I-131 irradiation differed among the lines; same doses (7.4-14.8 MBq/ml) caused the greatest damage in FRO cells, a modest effect in NPA and WRO, and only minimal change in B-CPAP. The combined effect was most demonstrable in wells treated with Dox and radioiodine, whereas the addition of CDDP or 5-FU had marginal or insignificant merit, respectively. In FRO cells, half-lethal doses of the above mentioned CDDP, Dox, and 5-FU, when used together with 14.8 MBq/ml I-131, reduced cell survival to 54.5%, 29.4% and 33.4%, respectively, vs. 60.2% with radioiodine alone. CONCLUSION: In vitro, clinical concentrations of Dox can accelerate the killing of thyroid cancer cells by radioiodine. These favorable experimental results warrant future studies to evaluate whether this new bidisciplinary approach is clinically relevant and feasible.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

A simplified double-injection method to quantify cerebral blood flow and vascular reserve using iodine-123 IMP-SPECT.

UNLABELLED: We developed and evaluated a simplified double-injection method for iodine-123 N-isopropyl-p-iodoamphetamine (IMP) to quantify regional cerebral blood flow (rCBF) twice in a single SPECT session. The method enabled rapid calculations of rCBF with five 10-minute SPECT scans, a fixed distribution volume (Vd), and one-point arterial blood sampling to calibrate a standard input function (SIF). METHODS: Sixty neurological patients were examined to measure rCBF twice in a single session of IMP-SPECT. Patients underwent frequent arterial blood sampling with two injections of IMP and acetazolamide challenge. We generated the SIF and determined the optimal Vd and calibration time (t(cal)) for the SIF in 30 patients. Validities of the fixed t(cal) and Vd were assessed in the remaining 30 patients. Simulation studies were also performed to evaluate the error sensitivity of the method. RESULTS: The optimal t(cal) and Vd were 34 min and 30 ml/ml, respectively. The method was robust in rCBF calculation with noisy SPECT data and yielded rCBF with negligible bias and acceptable errors compared with those obtained by the double-injection method previously reported. CONCLUSION: The method can be applied to measure rCBF twice in a single SPECT session more easily and less invasively.

Aged↗
PubMed2002

Causes of appearance of scintigraphic hot areas on thyroid scintigraphy analyzed with clinical features and comparative ultrasonographic findings.

This study was done retrospectively to analyze the ultrasonographic (US) findings in thyroid scintigraphic hot areas (HA). Three-thousand, eight-hundred and thirty-nine consecutive patients who underwent 99mTc-pertechnetate (n = 3435) or 123I (n = 457) scintigraphy were analyzed. HA were regarded as present when the tracer concentration was greater than the remaining thyroid tissue, or when hemilobar uptake was observed. High-resolution US examinations were performed with a real-time electronic linear scanner with a 7.5 or 10 MHz transducer. One hundred and four (2.7%) were found to be scintigraphic HA (n = 120). US revealed a nodular lesion or well-demarcated thyroid tissue corresponding to the HA in 94 areas (78.4%, Category 1), an ill-defined region with different echogenicity in 13 areas (10.8%, Category 2), and no correlating lesion in 13 areas (10.8%, Category 3). These 104 patients included 43 with adenomatous goiter (59 areas), 33 with adenoma, 11 with Hashimoto's thyroiditis, 5 with primary thyroid cancer, 4 with euthyroid ophthalmic Graves' disease (EOG), 3 with hemilobar atrophy or hypogenesis, 2 with hemilobar agenesis, 2 with hypothyroidism with blocking-type TSH-receptor antibodies (TSHRAb), I with acute suppurative thyroiditis. Among the 59 adenomatous nodules and 33 adenomas, 51 (86.4%) and 32 (97.0%), respectively, belonged to Category 1. A solitary toxic nodule was significantly larger and occurs more often in older patients than in younger patients. On the other hand, all 17 patients with known autoimmune thyroid diseases including Hashimoto's thyroiditis, EOG and hypothyroidism with blocking TSHRAb belonged to Category 2 or 3. Possible underlying mechanisms are 1) hyperfunctioning tumors or nodules, 2) localized functioning thyroid tissue freed from autoimmune destruction, inflammation or tumor invasion, 3) congenital abnormality, 4) clusters of hyperactive follicular cells caused by long-term TSH and/or TSHRAb stimulation, 5) asymmetry, etc. Scintigraphic HA are observed in patients with various thyroid diseases and high-resolution US appears to be helpful clinically for the differential diagnosis of the above mentioned disorders.

Adolescent↗
PubMed2002

Usefulness of a three-dimensional stereotaxic ROI template on anatomically standardised 99mTc-ECD SPET.

We have constructed a three-dimensional stereotaxic ROI template (3DSRT) on anatomically standardised cerebral blood flow (CBF) single-photon emission tomography (SPET) images to objectively estimate regional CBF (rCBF). The 3DSRT is composed of 259 regions of interest (ROIs) in 11 segments (1, superior frontal; 2, middle and inferior frontal; 3, primary sensorimotor; 4, parietal; 5, angular; 6, temporal; 7, occipital; 8, pericallosal; 9, lenticular nucleus; 10, thalamus; 11, hippocampus) on each side. We measured the rCBF values of the 518 ROIs and calculated the area-weighted average (segmental CBF; sCBF) of the 22 segments based on the rCBF in each ROI. We compared vascular reserve before and after revascularisation surgery using sCBF on anatomically standardised resting and acetazolamide (Acz)-challenged CBF SPET images, which were obtained using an equal-volume-split dual-injection single-day protocol [resting and vascular reserve (RVR) method] in 13 patients who had not suffered any major stroke but did have significant cerebrovascular stenosis. Prior to the evaluation, we examined the sCBF values of 16 subjects with various cerebrovascular conditions (8, normal; 3, lacunar infarction; 2, chronic infarction; 2, meningioma; 1, aneurysm) using physiological saline instead of Acz (placebo study) in order to confirm the reproducibility of the RVR method. In the placebo study we observed excellent linearity (y=1.444+0.964x) between the 352 pairs of baseline (x) and post-placebo (y) sCBF values in the 16 subjects, irrespective of the segment location. In all of the 13 patients, estimation of sCBF demonstrated impaired vascular reserve pre-operatively and improved vascular reserve postoperatively. We conclude that the 3DSRT, which could be identically set on the anatomically standardised images obtained at baseline and after Acz injection, allowed objective assessment of the pre- and postoperative vascular reserve, which was not easy with conventional ROI settings. While 3DSRT appeared useful for the evaluation of regional vascular reserve as well as rCBF, further study is necessary to clarify its general clinical value.

Acetazolamide↗
PubMed2002

Percutaneous radiofrequency ablation therapy after intrathoracic saline solution infusion for liver tumor in the hepatic dome.

Two liver tumors undetected by ultrasonography (US) because they were located in the hepatic dome were treated with radiofrequency (RF) ablation therapy after intrathoracic saline solution infusion. After administration of local anesthesia, artificial pneumothorax was produced by needle thoracentesis and a drainage catheter was inserted into the right thoracic cavity. After saline solution (450-500 mL) was injected into the thoracic cavity via the catheter, US-guided RF ablation was performed. No severe complications occurred and complete therapeutic effects were obtained. Percutaneous RF ablation therapy with intrathoracic saline solution injection seems to be a feasible alternative to other ablation therapies.

Carcinoma, Hepatocellular↗
PubMed2002

Renal tubular damage detected by dynamic micro-MRI with a dendrimer-based magnetic resonance contrast agent.

BACKGROUND: A noninvasive technique to evaluate the structure and function of the kidney would be useful to investigate renal diseases, especially acute renal failure. We have developed a novel technique to visualize functional micro-magnetic resonance (MR) images of the mouse kidney with a dendrimer-based macromolecular renal MR contrast agent. METHOD: Mice were injected with cisplatin or vehicle, then examined three days later by contrast-enhanced, dynamic high-resolution micro-MRI with 160 microm spatial resolution using a 1.5 T clinical MRI unit, a surface coil, and the renal contrast agent G4D-(1B4M-Gd)64. RESULTS: The cortex and outer stripe of the outer medulla of the mouse kidney were clearly visualized in the normal mice. In animals treated with cisplatin, the gradation of tubular damage as assessed by contrast enhanced dynamic MRI correlated with renal function. CONCLUSION: Contrast-enhanced, dynamic high-resolution micro-MRI with a novel dendrimer-based macromolecular renal MR contrast agent can be a powerful tool for in vivo observation of renal structural and functional damage.

Animals↗
PubMed2002

CT-guided transthoracic percutaneous ethanol injection for hepatocellular carcinoma not detectable with US.

PURPOSE: To evaluate the safety and effectiveness of computed tomography (CT)-guided percutaneous ethanol injection (PEI) for the treatment of hepatocellular carcinoma (HCC) not detectable with ultrasonography (US). MATERIALS AND METHODS: Between April 1994 and January 2001, 51 patients with 57 HCC nodules not detectable with US underwent CT-guided transthoracic PEI. Complications associated with the transthoracic approach, effectiveness of transthoracic PEI, and prognosis of the patients were evaluated. RESULTS: Seventy-one PEI sessions were performed for 57 nodules. Complications included pneumothorax in 21 sessions (30%) for 19 nodules (33%), moderate pleural effusion in four sessions (6%) for four nodules (7%), and hemoptysis in three sessions (4%) for two nodules (4%). A chest tube was required for pneumothorax in five sessions (7%) for five nodules (9%), and pleural effusion drainage was performed in two sessions (3%) for two nodules (4%). Apparent tumor necrosis was noted at CT in 51 nodules (89%). During follow-up (range, 3 months to 5(1/2) years; mean, 29 months +/- 18 [SD]), local recurrence was seen in seven nodules (12%), three of which received repeat treatment with transthoracic PEI. Twenty-six patients survived, and 25 patients died of multiple tumors, hepatic failure, or rupture of esophageal varices. CONCLUSION: Transthoracic PEI seems to be relatively safe and effective for the treatment of HCC not detectable with US.

Aged↗
PubMed2002

Small hepatocellular carcinoma: comparison of radio-frequency ablation and percutaneous microwave coagulation therapy.

PURPOSE: To evaluate the effectiveness of radio-frequency (RF) ablation and percutaneous microwave coagulation (PMC) for treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Seventy-two patients with 94 HCC nodules were randomly assigned to RF ablation and PMC groups. Thirty-six patients with 48 nodules were treated with RF ablation, and 36 patients with 46 nodules were treated with PMC. Therapeutic effect, residual foci of untreated disease, and complications of RF ablation and PMC were prospectively evaluated with statistical analyses. RESULTS: The number of treatment sessions per nodule was significantly lower in the RF ablation group than in the PMC group (1.1 vs 2.4; P <.001). Complete therapeutic effect was achieved in 46 (96%) of 48 nodules treated with RF ablation and in 41 (89%) of 46 nodules treated with PMC (P =.26). Major complications occurred in one patient treated with RF ablation and in four patients treated with PMC (P =.36). During follow-up (range, 6-27 months), residual foci of untreated disease were seen in four of 48 nodules treated with RF ablation and in eight of 46 nodules treated with PMC. No significant difference in rates of residual foci of untreated disease was noted (P =.20, log-rank test). CONCLUSION: RF ablation and PMC thus far have had equivalent therapeutic effects, complication rates, and rates of residual foci of untreated disease. However, RF tumor ablation can be achieved with fewer sessions.

Adult↗