Deep learning model combined with computed tomography features to preoperatively predicting the risk stratification of gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GIST)are prevalent neoplasm originating from the gastrointestinal mesenchyme.Approximately 50%of GIST patients experience tumor recurrence within 5 years.Thus,there is a pressing need to accurately evaluate risk stratification preoperatively.AIM To assess the application of a deep learning model(DLM)combined with computed tomography features for predicting risk stratification of GISTs.METHODS Preoperative contrast-enhanced computed tomography(CECT)images of 551 GIST patients were retrospectively analyzed.All image features were independently analyzed by two radiologists.Quantitative parameters were statistically analyzed to identify significant predictors of high-risk malignancy.Patients were randomly assigned to the training(n=386)and validation cohorts(n=165).A DLM and a combined DLM were established for predicting the GIST risk stratification using convolutional neural network and subsequently evaluated in the validation cohort.RESULTS Among the analyzed CECT image features,tumor size,ulceration,and enlarged feeding vessels were identified as significant risk predictors(P<0.05).In DLM,the overall area under the receiver operating characteristic curve(AUROC)was 0.88,with the accuracy(ACC)and AUROCs for each stratification being 87%and 0.96 for low-risk,79%and 0.74 for intermediate-risk,and 84%and 0.90 for high-risk,respectively.The overall ACC and AUROC were 84%and 0.94 in the combined model.The ACC and AUROCs for each risk stratification were 92%and 0.97 for low-risk,87%and 0.83 for intermediate-risk,and 90%and 0.96 for high-risk,respectively.Differences in AUROCs for each risk stratification between the two models were significant(P<0.05).CONCLUSION A combined DLM with satisfactory performance for preoperatively predicting GIST stratifications was developed using routine computed tomography data,demonstrating superiority compared to DLM.

Pancreatic neuroendocrine tumor detected by technetium-99m methoxy-2-isobutylisonitrile single photon emission computed tomography/computed tomography:A case report

BACKGROUND Pancreatic neuroendocrine tumors(NETs)account for about 1%–2%of pancreatic tumors and about 8%of all NETs.Computed tomography(CT),magnetic resonance imaging,and endoscopic ultrasound are common imaging modalities for the diagnosis of pancreatic NETs.Furthermore,somatostatin receptor imaging is of great value for diagnosing pancreatic NETs.Herein,we report the efficacy of technetium-99m methoxy-2-isobutylisonitrile(99mTc-MIBI)single photon emission CT(SPECT)/CT for detecting pancreatic NETs.CASE SUMMARY A 57-year-old woman presented to our hospital with a 1-d history of persistent upper abdominal distending pain.The distending pain in the upper abdomen was aggravated after eating,with nausea and retching.Routine blood test results showed a high neutrophil percentage,low leukomonocyte and monocyte percentages,and low leukomonocyte and eosinophil counts.Amylase,liver and kidney function,and tumor markers alpha-fetoprotein,carcinoembryonic antigen,and cancer antigen(CA)125,CA72-4,CA19-9,and CA153 were normal.Abdominal CT showed a mass,with multiple calcifications between the pancreas and the spleen.The boundary between the mass and the pancreas and spleen was poorly defined.Contrast-enhanced CT revealed that the upper abdominal mass was unevenly and gradually enhanced.99mTc-MIBI SPECT/CT revealed that a focal radioactive concentration,with mild radioactive concentration extending into the upper abdominal mass,was present at the pancreatic body and tail.The 99mTc-MIBI SPECT/CT manifestations were consistent with the final pathological diagnosis of pancreatic NET.CONCLUSION 99mTc-MIBI SPECT/CT appears to be a valuable tool for detecting pancreatic NETs.

A correlation of computed tomography perfusion and histopathology in tumor edges of hepatocellular carcinoma

BACKGROUND： The peripheral morphologic characteristics of hepatocellular carcinoma （HCC） reflect tumor growth patterns. Computed tomography （CT） perfusion is a new method to analyze hemodynamic changes in tissues. We assessed the relationship between CT perfusion and histopathologic findings in the periphery of HCC lesions. METHODS： Non-contrast CT, enhanced dual-phase CT, and CT perfusion were performed on 77 subjects （47 patients and 30 controls）. Based on the imaging findings of enhanced dual- phase CT, the tumor edges were classified into three types： type Ⅰ （sharp）; type Ⅱ （blurry）; and type Ⅲ （mixed）. The CT perfusion parameters included hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion. The tissue sections from resected specimens were subjected to routine hematoxylin and eosin staining and immunohistochemical staining for CD34. The correlations between microvessel density （MVD） and the CT perfusion parameters were analyzed using Pearson＇s product-moment correlation coefficient. Changes in the perfusion parameters in tumor edges of different tumor types were evaluated. RESULTS： Type Ⅰ （sharp）： the pathologic findings showed fibrous connective tissue capsules in the tumor edges, and an MVD 〈30/ram2. Type Ⅱ （blurry）： the histology showed that the edges were clear with no capsules and an MVD 〉30/ram2. Type Ⅲ （mixed）： the pathology was similar to that of types I and II, and an MVD 〉30/mm~. Hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion were significantly increased in the tumor edges of HCC patients compared to those of the controls （P〈0.05）. The correlation between CT perfusion parameters and MVD was higher in blurry tumor edges of type II than in those of types Ⅰ or Ⅲ. CONCLUSION： CT perfusion imaging of tumor edges may be helpful in revealing histopathological features, and indirectly reflect angiogenic changes of HCCs.

Experimental study on angiogenesis in rabbit VX_2 brain tumor using perfusion CT

Objective： To study the perfusion CT features of rabbit VX2 brain tumor with correlation to MVD and VEGF, and to validate perfusion CT for reflection of tumor angiogenesis. Methods： Rabbit VX2 brain tumor model was established by injection of 100 μL viable tumor cells （10qmL） through a 2 mm-hole 5 mm to the right of the sagittal suture and 5 mm posterior to the coronal suture bored by dental drill. MRI was performed every 2 days after seven days of implantation to evaluate the growth of the tumor. Twenty New Zealand White rabbits with tumor size over 3 mm in diameter were randomly divided into 2 groups according to the tumor growth time with those less than 3 weeks as group 1 and those more than 3 weeks as group 2, and perfusion CT were performed accordingly. CT measurements of BV, BF and PS from tumor, peritumor and contralateral normal tissue regions were obtained. After that the animals were sacrificed and 2% Evans blue （2 mL/kg） was given intravenously in 16 of these animals 1 h prior to sacrifice to detect breakdown of the blood brain barrier. VEGF and MVD were evaluated in immunohistochemical examination of the specimens. Results： Tumor had significantly higher BV, BF and PS （P=0.000） than peritumor and normal tissue region. Tumor BV, BF and MVD in group 2 were significantly higher than that in group 1 （P〈0.01）. Significant linear correlation was found between MVD and BV （t=-0.915, P=-0.000）, MVD and BF （t=0.901, P=-0.000）, and MVD and PS （t=-0.459, P=0.042）. We also found a rank correlation between PS and blue stain of tumor （rs=0.861, P=0.000）. Conclusion： Perfusion CT can distinguish tumor from peritumor and normal tissue clearly, reflect tumor angiogenesis accurately, and provide useful information for the evaluation of brain tumor.

Repair of abnormal perfusion foci in idiopathic epilepsy patients under long-term antiepileptic treatment

Epileptic seizure control and the disappearance of epileptJform discharge are not indicative of the absence of abnormal perfusion foci. Perfusion abnormalities are a major cause of epileptic discharge, and the existence of abnormal perfusion loci implies possible relapse. Very little is known about perfusion abnormality repair in epilepsy. The present study selected 43 cases of idiopathic epilepsy under antiepileptic drug control for an average of 24 months. Comparisons between interictal single-photon emission CT （SPECT） images and long-term electroencephalogram （EEG） pre- and post-treatment showed that cases of normal SPECT increased by 48% （12/25） following treatment, with a total number of 15 reduced loci （,36%, 15/41 ）. Perfusion foci, Le., region of interest, were altered following treatment. These changes included： normal to abnormal in 3 cases （7%, 3/43; 2 hyperperfusion and 1 hypoperfusion）; abnormal to normal in 14 cases （32%, 14/43; 10 pre-treatment hypopeffusion and 4 hyperperfusion）; abnormal to abnormal in 7 cases （16%, 7/43; hyperperfusion to hypoperfusion in 5 cases, hypoperfusion to hyperpeffusion in 2 cases）. Long-term EEG revealed in an increase in the number of normal cases by 20 （40%, 20/39）, and there were 25 fewer cases with epileptiform discharges （66%, 25/38）. These findings demonstrate that long-term control of anti-epileptic drugs partially repaired cerebral perfusion abnormalities and reduced epileptiform discharges in idiopathic epilepsy.

Tall gastrodis tuber combined with antiepileptic drugs repairs abnormal perfusion foci in focal epilepsy

One hundred patients with focal epilepsy were recruited for the present study and their seizures controlled with antiepileptic drugs. The patients then orally received a capsule of tall gastrodis tuber powder, a traditional Chinese drug, and underwent single photon emission computed tomography, long-term electroencephalogram, and CT/MRI. Blood drug levels were monitored throughout the study. Before treatment with tall gastrodis tuber, 35 of the 100 cases had abnormal CT/MRI scans; 79 cases had abnormal single photon emission computed tomography images; 86 cases had abnormal electroencephalogram; and a total of 146 abnormal perfusion foci were observed across the 100 subjects. After treatment, the number of patients with normal single photon emission computed tomography images increased by 12; normal electroencephalogram was observed in an additional 27 cases and the number of patients with epileptiform discharge decreased by 29 （34% of 86）; the total number of abnormal perfusion foci decreased by 52 （36%） and changes in abnormal loci were visible in 65 patients. These changes indicate that the administration of tall gastrodis tuber in combination with antiepileptic drugs repairs abnormal perfusion foci in patients with focal epilepsy Our results demonstrate that traditional Chinese drugs can repair abnormal perfusion foci and, as such, are a promising new pathway in the treatment of focal epilepsy.

Imaging of the Extra-axial Tumors and Tumor-like Lesions Involving both Middle and Posterior Cranial Fossae: Classification and Diagnosis

Objective: To study the imaging features of extra-axial tumors and tumor-likelesions involving both middle and posterior cranial fossae and to make a classification. Methods:Sixty cases of pathologically confirmed extra-axil tumors and tumor-like lesions involving bothmiddle and posterior cranial fossae were analyzed. They were divided into central and lateral types,the latter of which were subdivided into three types: middle cranial fossae type, posterior cranialfossae type and the over-riding type. The constitution and imaging features of each type wereanalyzed. Results: There were 12 cases of central type, including chordoma (n=5), pituitary adenoma(n=3), nasopharyngeal carcinoma (n=2), craniopharyn-gioma (n=1) and meningioma (n=l). 48 cases oflateral type including trigeminal nerve tumors (n=14), meningioma (n=12), epidermoid cyst (n=11),dural cavernous hemangioma (n=4), dermoid cyst (n=2), metastasis (n=2), hemangiopericytoma (n=1),paraganglioma of glonius jugular (n=1) and nasopharyngeal carcinoma (n=1). Each type of the lesionshad its own shape features, some of which were characteristic for some specific tumors. Most of thetumors and tumor-like lesions could be qualitatively diagnosed according to their imagingcharacteristics and the extent of the lesions could be defined definitely. Conclusion: It is helpfulto categorize extra-axial tumors and tumor-like lesions involving both middle and posterior cranialfossae according to their location for qualitative diagnosis and description of the extent of theselesions. It is of great clinical value in providing more precise and thorough imaging informationfor planning therapeutic methods and route of operation.

Primary Malignant Renal Tumors in Infancy and Childhood: CT Appearances

Objective： To investigate the imaging manifestation of primary malignant renal tumor with CT. Methods： Forty-three cases of surgically and pathologically confirmed primary malignant renal tumor were retrospectively reviewed. Un-contrast and contrast CT was performed in all 43 patients in which 15 patients received MRI examination. Results： The residual normal renal tissue of 29 cases out of 34 cases of Wilms＇ tumor was enhanced and manifested ＂crescent sign＂ or ＂ring sign＂. Four cases of malignant rabdoid tumor （RTK） manifested as large mass with notable necrosis and subcapsular fluid collection; Two cases of clear cell sarcoma （CCS） showed metastases to the skull which could indicate the diagnosis; Renal cell carcinoma （RCC） （n=3） showed calcification in 1 case. Conclusion： CT can precisely delineate the location, size, extent of involvement, imaging characteristics and metastases of renal tumor, which can provide information necessary to the clinical staging, therapy planning and prognosis of the tumors.

Comparing Gross Tumor Volume of Delineation between CT and MRI for Nasopharyngeal Carcinoma

Objective: To study the accuracy between CT and MRI in delineating gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) in making radiotherapy plan. Methods: The clinical data of 39 cases pathologically proven as nasopharyngeal carcinoma selected from April 2003 to September 2004 were retrospectively analyzed. All were subjected to CT and MR examination one week before treatment. CT scanning was performed with GE Light speed 16, and axial scan was parallel to the OM line routinely from soft palate to the suprasellar cistern. MR scanning was performed by GE Signa super-conducting magnetic resonance imaging system (1.5 Tesla). The standard quadrature head coil was used. Routine axial, sagittal and coronal image with SE sequence were obtained, and FLAIR was used in 10 of 21 cases. Scanned field ranged from the soft palate to the suprasellar cistern. Part of all cases underwent enhanced scanned with Ultravist in CT group or/and GD-DTPA in MR group. All data were analyzed by using the paired-samples t test. Results: The media primary tumor volume (cm3) in CT group and MR group was 32.49±19.91, 29.06±18.75, respectively, and the difference between the two groups were significant (t=5.268, P=0.000). There was significant difference between the two groups in early stage (T1+T2) and advanced stage (T3+T4) by Fuzhou Staging System (t=5.677, P=0.000; t=3.310, P=0.005, respectively). There was significant difference in stage T1, T2, T3 (P=0.005, P=0.001, P=0.004, respectively), and not in stage T4 (P=0.146) between the two groups. Conclusion: MR was more accurate than CT in delineating GTV of NPC, so, is more valuable in making radiotherapy plan.

Brain metastasis of hepatocellular carcinoma:A case report and review of the literature

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies in the world. It is more common in far eastern countries and relatively rare in the United States and western European countries where at autopsy it accounts for only 1-2% of malignant rumors, The disease is usually manifested in the the 6^th and 7^th decade of life. HCC is one of the highly malignant neoplasms, Extrahepatic metastases are seen in 64% of patients with HCC. The lungs, regional lymph nodes, kidney, bone marrow and adrenals are common sites of HCC metastasis^[1-3], But, metastasis to brain and skull is extremely rare. Table I shows some of the reported cases of HCC with brain metastasis. These case reports reaffirms the complex and multidisciplinary care of these patients^[4-5].

Value of Multi-slice spiral CT in diagnosis of malignant gastrointestinal stromal tumors

Objective： The aim of this study was to investigate the value of multi-slice spiral CT （MSCT） in the diagnosis of malignant gastrointestinal stromal tumors （GISTs）. Methods： Twenty-seven cases of MSCT images of malignant GIST proved by surgery and pathology were retrospectively analyzed. Both plain and enhanced CT scan was performed and multiplanar reconstruction was made in all cases. Results： The lesions originated from the stomach （n = 11）, small intestine （n = 9）, colon （n = 4）, rectum （n = 1）, and mesentery （n = 2）. The transverse diameters of mass were 4.2-22 cm, the edges clearly （n = 12）, unclearly （n = 15）. The mass were mainly irregular in shape Iobulated （n = 19）. The lesions were mainly heterogeneity on plain scan, moderate to marked enhancement in arterial phase and durative enhanced in venous phase. Cystic necrosis were observed in all the lesions, 9 cases were cystic and solid mixed mass. Hepatic metastases （n = 4）, pulmonary metastasis （n = 1）, lymphatic metastasis （n = 2） were detected. The accuracy rate of MSCT diagnosis for location and pathologic features of GISTs were 85.2% （23/27） and 77.8% （21/27）. Conclusion： Two-phase MSCT examination and axial images combined with multiplanar reconstruction images have important value for diagnosis of malignant GIST.

Malignant giant cell tumors of the tendon sheath of the right hip:A case report

BACKGROUND Malignant giant cell tumor of the tendon sheath(MGCTTS)is an extremely rare malignant tumor originating from synovial and tendon sheath tissue with highly aggressive biological behavior and a high rate of local recurrence and distant metastasis which should be considered a highly malignant sarcoma and managed aggressively.How to systemically treat MGCTTS remains a challenge.In this case,a patient with MGCTTS suffered a recurrence after 2 surgical resections received adjuvant chemotherapy and radiation therapy,but the treatment outcome remained poor.More clinical trials and better understanding of the biology and molecular aspects of this subtype of sarcoma are needed while novel medicines should be developed to efficiently target particular pathways.CASE SUMMARY A 52-year-old man presented with persistent dull pain in the right groin accompanied by limited right hip motion starting 6 mo ago.Two months before his attending to hospital,the patient’s pain worsened,presenting as severe pain when standing or walking,limping,and inability to straighten or move the right lower extremity.Surgical excision was performed and MGCTTS was confirmed by pathology examination.Two recurrences occurred after surgical resection,moreover,the treatment outcome remained poor after adjuvant chemotherapy and radiation therapy.The patient died only 10 mo after the initial diagnosis.CONCLUSION MGCTTS is characterized by a joint mass with pain and limited motion.It typically grows along the tendons and infiltrated into the surrounding muscle and bone tissue,with a stubborn tendency to relapse,as well as pulmonary metastasis.Radically surgical resection provides a choice of treatment whereas post-operation care should be taken to preserve the function of the joint.Chemotherapy and radiotherapy can be used as alternative treatments when radical resection cannot be performed.

Malignant giant cell tumor in the left upper arm soft tissue of an adolescent:A case report

BACKGROUND Giant cell tumor of soft tissue(GCT-ST)is an extremely rare low-grade soft tissue tumor that is originates in superficial tissue and rarely spreads deeper.GCT-ST has unpredictable behavior.It is mainly benign,but may sometimes become aggressive and potentially increase in size within a short period of time.CASE SUMMARY A 17-year-old man was suspected of having a fracture,based on radiography following left shoulder trauma.One month later,the swelling of the left shoulder continued to increase and the pain was obvious.Computed tomography(CT)revealed a soft tissue mass with strip-like calcifications in the left shoulder.The mass invaded the adjacent humerus and showed an insect-like area of destruction at the edge of the cortical bone of the upper humerus.The marrow cavity of the upper humerus was enlarged,and a soft tissue density was seen in the medullary cavity.Thoracic CT revealed multiple small nodules beneath the pleura of both lungs.A bone scan demonstrated increased activity in the left shoulder joint and proximal humerus.The mass showed mixed moderate hypointensity and hyperintensity on T1-weighted images,and mixed hyperintensity on T2-weighted fat-saturated images.The final diagnosis of GCT-ST was confirmed by pathology.CONCLUSION GCT-STs should be considered in the differential diagnosis of soft tissue tumors and monitored for large increases in size.

Postoperative multiple metastasis of clear cell sarcoma-like tumor of the gastrointestinal tract in adolescent:A case report

BACKGROUND Clear cell sarcoma-like tumor of the gastrointestinal tract(CCSLGT)is a rare malignant gastrointestinal mesenchymal soft tissue tumor.Its genetic feature is EWSR1 gene rearrangement.Histologically,it is often accompanied by a varying number of CD68-positive osteoclast-like giant cells.CCSLGT mostly occurs in the small intestinal wall of young people and children.In terms of clinical manifestations,there is no significant difference between it and other gastrointestinal tumors,and the diagnosis depends on immunohistochemistry and gene detection.CASE SUMMARY A 16-year-old man developed dizziness and fatigue 2 mo ago,and 10 d ago showed progressive exacerbation of paroxysmal epigastric pain and stopped flatulence and defecation.Computed tomography showed a soft tissue mass in the distal ileum.After complete resection of the lesion,it was diagnosed by combined immunohistochemical and genetic examination as CCSLGT.After surgery,the patient gradually developed lymph node,liver,lung,bone,left thigh,pleura and adrenal metastasis.The survival time was 4 years and 8 mo.CONCLUSION Whole abdominal computed tomography enhancement is recommended for patients with gastrointestinal symptoms.There is no effective treatment for CCSLGT with multiple metastases via the lymphatic system and bloodstream after surgical resection.

Intrathoracic solitary fibrous tumor: a report of 3 cases and review of the literature

Objective: The aim of this study was to investigate the imaging findings of intrathoracic solitary fibrous tumor (SFT), so as to improve its diagnosis and differential diagnosis. Methods: The clinical, imaging and pathological data of three intrathoracic SFTs confirmed by surgical pathology were analyzed retrospectively. There three cases all received spiral CT plain scan and enhanced scan, among which two multi-planar reformation (MPR) and one MR plain scan. And literatures were reviewed to investigate the imaging findings of intrathoracic SFT. Results: The three intrathoracic SFT located at intra-pulmonary, oblique fissure pleura and posterior chest wall visceral pleura, respectively. All were solitary masses. One case was a peripheral lung mass at dorsal segment of left lower lobe which CT plain scan showed as a soft tissue mass well circumscribed, enhanced scan showed that there were enhanced clustered, lineal small vascular signs in the mass during arterial phase, delayed scanning displayed that the mass showed heterogeneous enhancement and parts of solid content showed gradual enhancement, and there were shorter T1 signals on MRI T1WI, map-like high-low mixed signals on T2WI, mainly with short T2 signals. One case was an oblique fissure mass which plain scan showed as a homogeneous soft tissue mass with oval in shape and smooth edge, and enhanced scan showed moderate homogeneous enhancement. One case was a mass localized at posterior chest wall visceral pleura which CT plain scan showed as a heterogeneous mass, and enhanced scan showed that there was slight ring-like enhancement, large non-enhancing necrosis area in the mass and facing vessels in the vicinity region. All these three cases had no hilar and mediastinal lymphadenectasis. Operation and pathology results showed that the mass was well circumscribed, with capsule or false capsule. Under microscope, tumor cells were long fusiform, presenting bundle, turbulence or irregular arrangement. Hypocellular and hypercellular area appeared alternately, with interspersed coarse scar-like collagen fibers with hyalinization. There were hemangiopericytoma-like structures under parts of visual fields. There were bronchiole and alveolar epithelium in the legion at dorsal segment of left lower lobe in one case. The results of immunohistochemistry showed that the expressions of CD34 or CD99, Bcl-2 and vimentin were all strong positive. Conclusion: Intrathoracic SFT might be rare, which imaging findings could have relative characteristic features and diagnosis must depend on histopathology and immunohistochemistry examination.

MSCT and MRCP features of intraductal papillary mucinous tumor of the pancreas

Objective:To study the multi-slice CT(MSCT) and magnetic resonance cholangio-pancreatography(MRCP) features of intraductal papillary mucinous tumor(IPMT) of the pancreas.Methods:The clinical information,laboratory val-ues,imaging features and pathological findings of 8 cases were reviewed.Results:There were 6 males and 2 females with average 71.3 years old in this series.These lesions involved pancreatic branch ducts or main duct.Among them,2 cases were involved in the pancreatic uncinate process,1 case in the pancreatic head,1 in the pancreatic body,2 in the pancreatic tail and 2 cases involved multiple pancreatic duct.The common complaint was chronic upper abdominal pain.The imaging features included cystic lesion and it's association with the dilated pancreatic main duct,and bulging of the duodenal papilla.Mucin plug,septa or mural nodule were found in these cystic lesions.5 cases were confirmed with endoscopic retrograde cholangio-pancreatography(ERCP).3 cases had undergone surgery.Pathological findings of the 3 cases were adenoma,adenocarcinoma and borderline tumor,respectively.Conclusion:The MSCT and MRCP features of IPMT are somewhat characteristic,and the correct diagnosis can be made with the combination of clinical features.Diameter of branch duct ≥ 3 cm with multiple or large mural nodules,or severe dilated main duct indicates the probability of malignant IPMT.

Primary gastric melanoma: A case report with imaging findings and 5-year follow-up

BACKGROUND Most melanomas identified in the stomach are metastatic;primary gastric melanoma(PGM)is extremely rare,and the relevant studies are relatively scarce.PGM may be incorrectly diagnosed as other gastric malignant tumor types.CASE SUMMARY We describe a rare case of PGM confirmed through long-term clinical observation and pathological diagnosis.A 67-year-old woman presented to our hospital with recurrent chest tightness and chest pain.Digital gastrointestinal radiography revealed a circular shadow in the gastric cardia.Computed tomography(CT)revealed a heterogeneous tumor with uneven enhancement.Enlarged lymph nodes were noted in the lesser curvature of the stomach.On magnetic resonance imaging(MRI),T1-and T2-weighted imaging revealed hyperintensity in and hypointensity in the tumor,respectively,both of which increased substantially after uneven enhancement.Near total gastrectomy was performed,and the tumor was pathologically confirmed to be a gastric melanoma.Because no other possible primary site of malignant melanoma was suspected,a clinical diagnosis of PGM was made.The patient was followed for nearly 5 years,during which she received CT reexamination,but no recurrence or metastasis was observed.CONCLUSION Certain imaging characteristics could be revealed in PGM.Imaging examination can be of great value in preoperative diagnosis,differential diagnosis,and followup of patients with PGM.

Correspondence of CT perfusion imaging to pathological manifestations in rabbit models of hyperacute cerebral infarction

BACKGROUND： Could the infarction be diagnosed quickly and accurately at the acute stage by CT perfusion imaging （CTPI） technology？ Whether the images of CTPI will correspond with the pathological changes or not？ All the questions need to be solved by experimental and clinical studies. OBJECTIVE： To reveal the rules of perfusion map changes and guide the early diagnosis of hyperacute cerebral infarction by analyzing the correlation of CTPI with pathological manifestations for hyperacute cerebral infarction. DESIGN： A randomized controlled animal experiment. SETTING： Experimental Center of Medical Radiology, Longgang Central Hospital of Shenzhen City. MATERIALS： Forty-two adult New Zealand rabbits of （2.6±0.5） kg, either male or female, were randomly divided into experimental group （n =36） and control group （n =6）. Six rabbits in the experimental group were observed after ischemia for 0.5, 1, 2, 3, 4 and 6 hours respectively, and 1 rabbit in the control group was observed at each corresponding time point. METHODS： The experiments were carried out in the Experimental Center of Medical Radiology, Longgang Central Hospital of Shenzhen City from March 2003 to July 2004. Rabbit models of cerebral infarction were established by modified O＇Brein method. （1） The rabbits in the experimental group were scanned at 0.5, 1, 2, 3, 4 and 6 hours after ischemia respectively. The dynamic CT scan slice was 13 mm from the anterior edge of the frontal cortex, and six fake color functional images were obtained, including cerebral blood flow map （CBF map）, cerebral blood volume map （CBV map）, peak to enhancement map （PE map）, flow without vessels map, time to peak map （TP map）, time to start map （TS map）. The manifestations and changes of the functional maps in different interval were observed. （2） Bilateral symmetric ranges of interest （ROI） were drawn separately on the CBF map, CBV map, TP map and TS map. The blood flow parameters of focal and contralateral cerebral tissues could be obtained to calculate relative cerebral blood flow （rCBF, rCBF=focal CBF/contralateral CBF）, relative cerebral blood volume （rCBV, rCBV= focal CBV/contralateral CBV）, a relative time to peak （rTP, rTP= focal TP - contralateral TP）, a relative time to start （rTS, rTS= focal TP - contralateral TP）. （3） The perfusion maps were input into AutoCAD software. The percents of ischemic cores and peri-ischemic areas accounting for contralateral cerebral hemisphere were calculated. （4） The animals were anesthetized and killed, then the cerebellum and low brain stem were taken out. The brain tissues were cut on coronal plane at 14 mm from the anterior edge of the frontal cortex, a 2-mm piece anterior to the incision, and a 3-mm piece posterior to the incision. The anterior piece was fixed, stained and observed. A 1-mm slice was cut from the front of the posterior piece tissues as electron microscope sample, the remnant was fixed and then taken out, and the location and size of stained ＂white＂ areas were observed as the reference for electron microscope sample. （5） The correlation between CTPI and pathological manifestations was observed. MAIN OUTCOME MEASURES： （1） Laws of time and spatial changes of ischemic areas; （2） Pathological changes of the ischemic tissues; （3） Correspondency between CTPI and pathological manifestations. RESULTS： （1） Laws of time and spatial changes of ischemic areas： Relative ischemic-core areas were consistent in each perfusion map, increased incessantly along with the ischemic times. Relative peri-ischemic areas were inconsistent in each perfusion map, on CBF map from 1 to 6 hours after ischemia, the area of ischemic core increased from （1.503±0.523）% to （7.125± 1.054）%, the ascending trend occurred. But the peri-ischemic areas showed a descending trend on CBF map, the areas decreased from （8.960±0.719）% to （5.445 ± 0.884）% from 0.5 to 6 hours; The relative areas were the largest one on TP maps, the average value was （32.796±3.029）% at 0.5 hour after ischemia happening （60.540±1.683）% at 6 hours. The trend of ischemic areas was increased. No obvious change was observed on TS maps. （2） Pathological changes of the ischemic tissues： Under light microscope, there was no obvious change at 0.5- 2 hours after ischemia, edema at 3 hours, karyopycnosis at 4 hours and eosinophilous changes at 6 hours; Under electron microscope, there was edema in ischemic cores within 4 hours after ischemia, whereas karyopycnosis or structure vanished after 4 hours; Edema was observed in peri-ischemic areas. （3） Correlation between CTPI and pathological manifestations： On CTPI maps, the ischemic core was blue on CBF and CBV maps, black on TP and TS maps. Along with the ischemic times, the rCBF and rCBV decreased, whereas the rTP and rTS prolonged. Hemodynamic parameters were not significantly different within 2 hours of ischemia and 2 hours after ischemia. The rTP and rTS became 0 after 1 and 2 hours respectively. On CTPI maps the peri-ischemic area was red on CBF and CBV maps, red and yellow on TS maps, red on TP maps. Along with the ischemic times, the rCBF decreased, and the lowest level was always at about 20%, whereas the rTP and rTS prolonged. CONCLUSION： （1） CTPI manifestations corresponded well with pathological findings, and it is a sensitive, stable and reliable technique to diagnose hyperacute cerebral infarction. （2） TP map was more sensitive than CBF map and TS map in exhibiting the peri-ischemic areas, thus TP maps could be a good choice for observing peri-ischemic areas.

Comparative Study of CT Images of Cerebral Metastasis from Pulmonary Squamous Cell Carcinoma and Adenocarcinoma

Objective: To explore the di?erence of CT images of metastatic tumors to the brain of lung squamous cell cancer and lung glandular cancer. Methods: Forty-?ve cases of lung squamous cell cancer and 59 cases of lung glandular cancer have gone through pathological con?rmation and all the 104 cases have been put under enhanced scanning on the basis of ?at scanning. The shape and density of the metastatic tumors, encephaledema around the tumors, and the reinforcement change after the enhancement were analyzed. Results: The CT scanning images of all the cases showed that, under ?at scanning, the density of the metastatic tumors to the brain of lung squamous cell cancer was over the slightly-high level and by no means even. Again, under ?at scanning, some 10 cases of metastatic tumors to the brain of lung glandular cancer showed a slightly-high density and some 49 other cases a low density and sack-like low density. Forty-?ve cases of metastatic tumors to the brain of lung squamous cell cancer were with hydroncus while some 30 cases of that of lung glandular cancer were in the same condition. Most of the two types of metastatic tumors, amounting to 97 cases, took place in supratentorial manner, and only 7 cases took place in subtentorial manner. Conclusion: The CT images of metastatic tumors to the brain of lung squamous cell cancer and lung glandular cancer are obviously di?erent from each other. As for the lung squamous cell cancer, the ?at scanning density of the tumor is over the slightly-high level with unevenness. There is relatively obvious reinforcement and obvious hydroncus. As for the lung glandular cancer, the metastatic tumor to the brain shows a low density and sack-like low density under ?at scanning. There is no obvious reinforcement and relatively slight hydroncus.