The role of 99mTc-tetrofosmin scintigraphy for staging patients with laryngeal cancer

Diagnosis and staging of laryngeal cancer is currently based on physical examination, endoscopy, and imaging techniques such as computed tomography (CT) and/or magnetic resonance (MR) and histology. While imaging techniques have a pivotal role for defining the size of the primary tumor, they are less accurate for defining metastatic involvement of regional lymph nodes, especially if lymph nodes are smaller than 10-15 mm. The aim of this study was to comparatively assess the relevance of (99m)Tc-tetrofosmin scintigraphy for the staging of laryngeal tumors versus the CT scan. We evaluated the sensitivity of imaging with (99m)Tc-tetrofosmin in 28 consecutively enrolled patients with squamous cell laryngeal carcinoma. Total-body scintigraphy with 99mTc-tetrofosmin was performed preoperatively, and the results were compared to CT images of the neck and mediastinum. CT and (99m)Tc-tetrofosmin scintigraphy were equally sensitive (96%) in identifying the primary tumor. While CT was more sensitive for detecting metastatic lymph nodes (100% versus 50%), (99m)Tc-tetrofosmin scintigraphy was more specific (100% versus 56%; p < 0.04). The overall diagnostic capabilities of the two techniques for detecting lymph node metastases were comparable (Youden Index: J = 0.56 for CT and J = 0.50 for (99m)Tc-tetrofosmin scintigraphy). (99m)Tc-tetrofosmin scintigraphy is a useful complement to CT for staging laryngeal tumors, especially for detecting metastatic lymph nodes and distant metastases.     

Influence of the Application of MRI on the T, N Staging System of Nasopharyngeal Carcinoma

OBJECTIVE To investigate the influence of utilizing MRI on the T, N staging system (the 5th edition, UICC) and on the 1992 China staging systems (Fuzhou-Guangzhou,China) by comparing the results of CT and MRI examinations of nasopharyngeal carcinoma (NPC).METHODS All 56 NPC patients, which were confirmed by histology,accepted both CT and MRI examinations. CT system scans were obtained by using an Elscient CT Twin Flash with the conventional axial scan. Three cases were examined by an additional coronary scan and 16 patients received an enhanced CT. The MR imaging was performed with a 0.5T MR system (Philips T5- II Ultra-Magnetic). The conventional axial, sagittal and coronary sections with SE sequences were obtained. The scan field was from the supra sellar cistern to the inferior border of C2. Most patients (50/56) accepted contrast enhanced MRI.RESULTS The pharyngobasilar fascia can clearly be seen on MRI but not on CT, so MRI can accurately determine the lesion in the nasopharyngeal cavity. MRI is more sensitive for evaluation of tumor involvement of soft tissue such as the Iongus colli muscle (14 cases by CT and 26 by MRI), tensor veli patalini muscle and levator veli palatini muscle (17 cases by CT and 23 by MRI), and skull-base bone marrow invasion (15 cases by CT and 42 by MRI). MRI can also demonstrate the invasion of the carotid sheath area and the enlargement of retropharyngeal lymph nodes more definitely than CT.The involvement of the trigeminal nerve can be detected on MRI, which may influence the clinical staging directly.CONCLUSION Of the 56 cases examined, 16 (28.6%) changed the staging based on UICC staging; while 33.9% (19/56) cases changed based on the 1992 China-stagin9 system. The major influence of MRI examinations on the 1992 staging was to differentiate the involvement of the carotid sheath area from metastasis of the retropharyngeal lymph nodes. There also was a significant difference in finding early invasion of the skull base.     

500例原发性肝癌的磁共振表现

背景与目的:磁共振成像(magneticresonanceimaging,MRI)是肝内恶性肿瘤的主要影像学诊断方法之一。本文总结了500例原发性肝癌的MRI表现,以评价钆-二乙烯三胺五乙酸(gadolinium-diethylenetriaminepentaacetic,Gd-DTPA)增强及超顺磁氧化铁(superparamagneticironoxideparticles,SPIO)增强扫描对小肝癌的诊断价值。资料与方法:收集我院行MR检查并经病理确诊为原发性肝癌的患者500例,分别行平扫、平扫+Gd-DTPA增强T1加权扫描、平扫+Gd-DTPA增强T1加权+SPIO增强重T2加权扫描。结果:500例原发性肝癌中,小肝癌有65例(13%),结节型肝癌81例(16.2%),块状型肝癌325例(65%),弥漫型肝癌29例(5.8%);单发310例(62%),多发190例(38%)。全组淋巴结转移率为12%;静脉癌栓率为31.4%。非弥漫型肝癌的肿块最大直径与子灶、异叶转移、淋巴结转移、癌栓之间存在正相关(P<0.05)。65例小肝癌的病灶总数为71个,平扫和增强、Gd-DTPA+SPIO增强和Gd-DTPA增强所发现病灶的平均数之间均存在显著差异(P<0.05)。结论:非弥漫型肝癌的肿块直径越大越容易发生子灶、异叶转移,淋巴结转移及癌栓。MRI诊断小肝癌,增强扫描比平扫有利于发现较多的病灶,而SPIO+Gd-DTPA增强比单纯Gd-DTPA增强发现的病灶多。     

肺肉瘤样癌的临床病理分析

目的探讨肺肉瘤样癌（pulmonary sarcomatoid carcinoma,PSC）的临床病理学特征,以提高对肺肉瘤样癌的早期诊断。方法回顾性分析6例肺肉瘤样癌的临床特征、影像学表现及病理学特征。结果6例患者最常见的呼吸系统临床表现为咳嗽、咳痰（100．O％）,其次5例为痰中带血（83．3％）和4例胸痛（66．7％）;影像学表现为增强CT扫描可见肿块实体部分轻度强化,转移淋巴结环形强化1例,肺内转移3例,纵隔转移2例,腋窝淋巴结转移2例,胸膜及胸壁侵犯3例,胸腔积液3例,肋骨转移1例,肝转移1例,脑转移2例;病理诊断3例为多形性癌,2例梭形细胞癌,1例为巨细胞癌。结论肺肉瘤样癌临床少见,其临床表现无特异性,肺部增强cT检查具有一定的特异性,诊断仍需依靠病理学检查,免疫组织化学有助于确诊。     

Sensitivity of chest radiography, computed tomography, and gallium scanning to metastasis of lung carcinoma

To determine the efficacy of radiologic techniques in preoperative staging of the mediastinum for lung carcinoma, the authors studied 45 patients with chest films supplemented with oblique views, esophagrams, gallium scans, and computed tomograms (CT). They interpreted the studies and correlated surgical findings using a modified classification of lymph node regions. The mediastinum was positive on chest films in 14 of the 21 cases with pathologically proved mediastinal metastases (33% false-negative). Gallium scans in cases with a positive primary were positive in 12 of 15 cases with mediastinal or hilar metastases (20% false-negative). Computed tomography showed nodes over 1 or 1.5 cm in size in or adjacent to the biopsy-positive node region in 18 of 19 patients (5% false-negative), extranodal mediastinal involvement, and 9 of 10 proven hilar metastases. Computed tomography is a sensitive screening technique in patients who would otherwise require an invasive staging procedure, but is not highly specific (false-positive rate 38%).     

Comparison of clinical staging algorithms and 111indium-capromab pendetide immunoscintigraphy in the prediction of lymph node involvement in high risk prostate carcinoma patients

BACKGROUND: The pretherapy prediction of occult lymph node involvement and the avoidance of otherwise futile and potentially morbid definitive local therapy is paramount in men with newly diagnosed prostate carcinoma. To identify patients with prostate carcinoma who likely have lymph node involvement and would benefit from staging lymphadenectomy prior to definitive local therapy, the authors compared the ability of several predictive staging algorithms and a radiolabeled monoclonal antibody scan to predict lymphatic metastases prior to treatment. METHODS: Between August 1991 and June 1994, 198 men with clinical T2 or T3 classified (TNM) prostate carcinoma (bone scan negative) who were at high risk of lymph node involvement underwent a 111In-capromab pendetide scan prior to staging lymphadenectomy. Several predictive models based on preoperative prostate specific antigen level, biopsy Gleason score, and clinical stage were selected to predict those men having a > or =20% probability of lymph node involvement. The ability to predict pathologic stage using several clinical algorithms and the monoclonal antibody scan was compared with pathologic examination of the lymph nodes. RESULTS: Overall, 39% of the pelvic lymph node specimens were positive for metastatic disease by pathologic analysis. Published algorithms predicting lymph node metastases had a positive predictive value (PPV) ranging from 40.5% to 46.6% and an area under the receiver operating characteristic curve (AUC) ranging from 0.52 to 0.61. The monoclonal antibody scan had a PPV of 66.7% and an AUC of 0.71. The differences between the PPV and the AUC for the individual clinical algorithms when compared with immunoscintigraphy were statistically significant. Combining the radiolabeled monoclonal antibody scan with clinical predictive models, a PPV of up to 72.1% could be obtained. CONCLUSIONS: These data suggest that the PPVs for the clinical predictive algorithms are similar and that the PPV of the radiolabeled monoclonal antibody scan alone or in combination with the algorithms has additional value in predicting lymph node involvement in prostate carcinoma patients at high risk of regional disease spread. These algorithms and the 111In-capromab pendetide scan may be used for the appropriate selection of candidates for definitive local therapy in men with clinically localized prostate carcinoma and significant risk of lymph node involvement.     

18F-FDG hPET/CT显像在原发性贲门癌中的应用

背景与目的：dPET／CT检查价格昂贵、而hPET／CT显像检查虽在准确性尚不及dPET，但其性价比较高．有较好的应用前景，本文探讨^18F-脱氧葡萄糖（FDG）双探头hPET／CT显像在原发性贲门癌中的应用价值。方法：26例经组织病理学证实的原发性贲门癌患者进行^18F-FDG双探头hPET／CT显像。图象分析采用视觉及半定量方法，同时与近期CT结果比较。结果：①双探头hPET／CT检出原发性贲门癌的灵敏度为92．3％（24／26例），2例假阴性患者均属印戒细胞癌，原发肿瘤直径〈2cm（T1期）。②19例手术患者中，贲门局部淋巴结转移15例，双探头hPET／CT检出8例，其灵敏度、特异性和准确性分别为71．4％、100％和53．3％，CT检出3例。③双探头hPET／CT检出远处转移7例，CT仅检出3例。结论：^18F-FDG双探头hPET／CT诊断原发性贲门癌较为灵敏，检出贲门局部淋巴结转移和远处转移可能优于CT。因此hPET／CT显像对贲门癌的术前分期和手术方案有一定的指导作用。     

FDG PET在鼻咽癌分期中的作用(26例评估分析)

[目的]探讨18F-FDGPET在评价鼻咽癌分期中的作用。[方法]对26例经病理证实且经B超、X线胸片检查没有发现远处转移的鼻咽癌患者在治疗前进行了PET/CT或PET检查,与同期的CT图像比较,并对PET的检查结果与CT检查结果不一致的患者进行了进一步检查。[结果]FDGPET与CT对原发肿瘤的评价方面没有差别;FDGPET改变了26例患者中5例患者的N分期,其中3例患者的N分期由N3b改为M1。[结论]FDGPET在检查鼻咽癌淋巴结转移和远处转移方面比CT更敏感。     

甲状腺癌的CT诊断研究

目的评价甲状腺癌的CT诊断价值。方法回顾性分析46例甲状腺癌患者术前CT检查及术后病理检查结果。结果所有病例CT扫描均可见肿块,其边缘均不清楚,呈浸润性生长。36例肿瘤为实性,患侧甲状腺体积增大,失去正常解剖形态,其密度不均匀,均可见不同程度的低密度区,无明确分界;增强扫描肿瘤呈不均匀强化。10例为囊性,伴高密度乳头状结节,囊壁厚薄不均,囊壁及结节有钙化。气管受侵12例,颈鞘血管受侵8例,食管受侵4例。颈部淋巴结转移22例,同侧转移14例,双侧转移9例。结论甲状腺癌的CT表现具有一定特征性,可作为判断甲状腺癌有无侵犯颈鞘血管和气管的依据,为选择临床治疗方法提供参考依据。     

多层螺旋CT在直肠癌术前分期中的诊断价值

背景与目的:直肠癌术前分期对选择合理治疗方案和判断预后至关重要。传统的计算机断层扫描(computed tomography,CT)对直肠癌术前分期存在争议,本研究旨在探讨多层螺旋CT(multislice spiral CT,MSCT)对直肠癌术前分期的诊断价值。方法:中山大学肿瘤防治中心2006年3月至2007年2月,经病理证实的直肠癌患者87例,所有患者术前行MSCT平扫及增强扫描,由两位放射科医生独立评价肿瘤的部位、大小、侵犯范围(T)、淋巴结转移(N)及远处转移(M)情况,做出诊断及TNM分期,并与术后病理对照,评价准确性、灵敏度及特异度。结果:MSCT检出了全部87例直肠癌,对直肠癌TNM分期总的准确性为81.6%(71/87)。T、N、M期准确性分别为94.3%(82/87)、82.8%(72/87)、98.9%(86/87)。≤T2、T3、T4期灵敏度分别为90.5%、91.3%、97.7%,特异度分别为98.5%、94.2%、97.7%。N0、N1、N2期灵敏度分别为92.9%、72.0%、82.4%,特异度分别为88.9%、88.5%、91.7%。远处转移的患者仅1例因肝脏转移灶<5mm而漏诊。结论:MSCT能较准确地判断直肠癌的侵犯范围、淋巴结转移及远处转移,是非常有价值的术前分期方法。     

子宫颈癌盆腔淋巴结转移的术前CT评价

目的：探讨螺旋CT检查对子宫颈癌盆腔淋巴结转移的诊断价值。方法：60例经临床及病理诊断为子宫颈癌的患者，做子宫颈癌根治术之前行盆腔螺旋CT检查，并以术后病理检查为金标准进行对照，按病例数和盆腔淋巴结部位(粒)数分别计算CT检查的灵敏度、特异度、Youden指数。结果：术前盆腔淋巴结螺旋CT检查的病例对照和部位对照的灵敏度分别为33．3％、28．6％，特异度分别为100％、98．8％，Youden指数分别为0．333、0．274。结论：螺旋CT检查对诊断子宫颈癌盆腔淋巴结转移的特异度较高，具有一定的参考价值；但灵敏度偏低，有待改进。     

肺低分化鳞癌:CT表现特点及术前CT分期的价值

摘要目的探讨CT影像表现特征及术前CT检查在肺低分化鳞癌T及N分期中的价值。方法2000年5月～2006年5月共有179例肺低分化鳞癌患者在我院进行了CT扫描检查（其中132例患者接受了肺叶切除术）。其中行CT增强扫描者142例,行CT平扫37例。所有患者均经病理诊断证实。由2位科放射科医师共同对所有患者的CT扫描结果进行影像学分析、分期（包括原发肿瘤及淋巴结病变）,并与病理诊断结果进行对照研究。结果在所有179例肺低分化鳞癌患者,中央型病变53．6％（96例）,周围型病变46．4％（83例）。96例中央型病变患者中,CT影像学表现为肺门肿块者94例,腔内型病变者2例,出现空洞者5例,伴随阻塞性改变者69例。83例周围型病变患者中,最大径范围1．5—12cm,82例为实性病变,1例为部分实性病变;其中48例（58．0％）患者的病灶直径〉4cm,伴空洞病变表现的患者12例（14．0％）。直径≤3cm的病灶占周围型病变的21例（25．3％）,中心可出现坏死（12例）及空洞（2例）,可见广泛淋巴结肿大（3例）。术前CT对原发肿瘤及淋巴结分期（cTN）与术后病理对原发肿瘤及淋巴结分期（pTN）一致者46．2％（61例）,cTN与pTN不一致者53．8％（71例）。CT对原发肿瘤（T分期）评估准确者78．8％（104例）,不准确者21．2％（28例）,其中低估12．1％（16例）,高估9．1％（12例）。CT对淋巴结病变（N分期）评估准确者56．8％（75例）,不准确者43．2％（57例）,其中低估18．2％（24例）,高估25．0％（33例）。结论肺低分化鳞癌多为典型鳞癌的CT表现。病灶直径≤3cm的周围型低分化肺鳞癌可发生坏死及纵隔广泛淋巴结转移。直径〈1cm的纵隔淋巴结可转移,而良性淋巴结肿大亦较常见。尽管CT在低分化鳞癌分期上价值有限,但仍具有重要作用。     

The incremental effect of positron emission tomography on diagnostic accuracy in the initial staging of esophageal carcinoma

BACKGROUND: The purpose of the current study was to assess whether [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) provides incremental value (e.g., additional information on lymph node involvement or the presence of distant metastases) compared with computed tomography (CT) in patients with esophageal carcinoma. METHODS: The authors examined 149 consecutive patients with thoracic esophageal carcinoma. Eighty-one patients underwent radical esophagectomy without pretreatment, 17 received chemoradiotherapy followed by surgery, 3 underwent endoscopic mucosal resection, and the remaining 48 patients received definitive radiotherapy and chemotherapy. The diagnostic accuracy of FDG-PET and CT was evaluated at the time of diagnosis. RESULTS: The primary tumor was visualized using FDG-PET in 119 (80%) of 149 patients. Regarding lymph node metastases, FDG-PET had 32% sensitivity, 99% specificity, and 93% accuracy for individual lymph node group evaluation and 55% sensitivity, 90% specificity, and 72% accuracy for lymph node staging evaluation. PET exhibited incremental value over CT with regard to lymph node status in 14 of 98 patients who received surgery: 6 patients with negative CT findings were eventually shown to have lymph node metastases (i.e., they had positive PET findings and a positive reference standard [RS]); 6 patients with positive CT findings were shown not to have lymph node metastases (i.e., they had negative PET findings and a negative RS); and 2 patients were shown to have cervical lymph node metastases in addition to mediastinal or abdominal lymph node metastases. Among the remaining patients, PET showed incremental value over CT with regard to distant organ metastases in six patients. The overall incremental value of PET compared with CT with regard to staging accuracy was 14% (20 of 149 patients). CONCLUSIONS: FDG-PET provided incremental value over CT in the initial staging of esophageal carcinoma. At present, combined PET-CT may be the most effective method available for the preoperative staging of esophageal tumors.     

Diagnosis and significance of liver metastases in small cell carcinoma of the lung

One hundred fifty-seven consecutive patients with small cell lung cancer seen at the National Cancer Institute over a four-year period underwent a series of pretherapy liver staging procedures to determine optimal means of detection and prognostic implications of hepatic metastases. Liver evaluation included physical examination, liver function tests, and liver scan (radionuclide or computerized tomography [CT]), as well as percutaneous and/or peritoneoscopy-directed liver biopsy when possible (74%). Liver metastases were detected in 26% of patients. Peritoneoscopy was the most sensitive method of liver evaluation and increased the detection of liver metastases when done in a sequential fashion after percutaneous liver biopsy from 18 to a total of 27 patients. Of the noninvasive procedures, radionuclide and CT liver scan were the most accurate concurring with liver biopsy in 87% of patients but permitting correct discrimination of stage in excess of 96% of patients. The accuracy of this noninvasive procedure was enhanced by an algorithm combining the results of radionuclide liver scan with liver function tests to detect patients with high or low likelihood of liver involvement. The survival and response of patients with liver metastases was significantly worse than those without such metastases with no three-year disease-free survivors among patients with liver metastases.     

鼻咽癌茎突后间隙侵犯与颈深上淋巴结转移的初步探讨

From March 1985 to September 1988, 38 out-patients with nasopharyngeal carcinoma (NPC), proven by pathology and examined by CT scan or MRI with involvement of deep upper cervical lymph nodes larger than 2 cm, were treated. The invasion of the poststyloid space is probably caused by metastases of the lymph nodes deep-seated in the neck and not by direct infiltration of the primary tumor. In TNM staging, it should be considered as N1, but not T3. As to the design of radiotherapy for these cases, the upper margin of the cervical field should be moved up to the level of the external auditory meatus in order to encompass the base of the skull. If lymph nodes in the mastoid cells on the same side are involved, beta-beams with energy not lower than 15 Mev should be used to ensure enough dose in the target volume.     

儿童原发性恶性肾肿瘤的CT表现

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.     

儿童原发性恶性肾肿瘤的CT表现

目的探讨小儿恶性肾肿瘤的CT表现特征。方法回顾分析43例经手术、病理证实的儿童原发性恶性肾肿瘤的CT表现。全部病例行CT平扫与增强检查,15例同时行MRI 检查。结果 43例中,Wilms瘤34例,其中29例残肾强化呈“新月形、环形”征;肾恶性杆状细胞瘤4例,均有瘤体大、大片坏死及肾包膜下新月形低密度积液;肾透明细胞肉瘤2例,颅骨转移是重要佐征;肾细胞癌3例,1例有钙化。结论 CT检查可准确显示肾肿瘤的部位、大小、侵犯范围、影像特点及转移情况,为肿瘤的临床分期、制定治疗方案、估计预后提供重要依据。     

嗅神经母细胞瘤的CT应用评价

目的 探讨ＣＴ在 嗅神经母细胞瘤诊断,分期与疗后随访中的价值。方法 对１３例经病理证实的嗅神经母细胞瘤ＣＴ资料结合文献进行回顾性分析。结果 １３例中,１１例行术前ＣＴ检查,按Ｋａｄｌｉｓｈ标准分期：Ｂ期４例,Ｃ期７例。全组病灶平扫呈软组织密度,３例内部要见钙化灶,４例平扫＋增强病残暴球均匀明显强化;６便直接增强扫描病灶密度明显高于周转软组织。４例行术后复查者,在３个月至２年内均有复发。病灶侵犯鼻腔     

123例贲门癌外科治疗的临床分析

背景与目的：贲门癌的发病率逐年增高,对其研究逐渐深入,但在临床上还有很多争论。本文总结我们在贲门癌临床外科治疗中的经验。方法：123例手术治疗的贲门癌患者：经胸手术组72例,经腹手术组40例,胸腹联合手术组11例,分析术前检查（腹部B超、胸腹CT、内镜和上消化道造影）、手术入路、淋巴结清扫和术后病理情况。结果：腹部B超对浆膜受侵、淋巴结转移、下段食管受侵、肝转移病变外侵腹水的判断与术后病理的符合率分别达到了71．2％、62．2％、47．8％、100％,胸腹CT则为78．6％、72．7％、51．9％、100％,内镜指示肿瘤距门齿的长度,上消化道造影则显示肿瘤与膈肌的关系。手术切除率94．3％（116／123）．116例切除病例中,贲门腺癌108例,占93．1％,腺鳞癌、鳞癌、不典型类癌、类癌各2例,占6．9％,84例腹腔淋巴结转移（72．4％）,6例胸腔淋巴结转移（7．1％）,40例（34．5％）下段食管受侵。结论：术前腹部B超和胸腹CT检查对判断肿瘤切除有极大帮助。内镜和上消化道造影有助于判断是否开胸。淋巴结转移以腹腔为主。三种手术途径各有优劣,没有任何一种占绝对优势,要依托Siewert分型,因病而定、因人而异。     

Comparison of immunoscintigraphy and computerized tomography in identifying colorectal cancer: individual lesion analysis

Monoclonal antibody scintigraphy with 111In-ZCE025 was used in presurgical staging of 45 patients prior to abdominal exploration for primary, recurrent or metastatic colorectal carcinoma. A total of 186 lesions were identified, of which 147 were evaluated by abdominal surgery and pathology. Sensitivity was 40.5% (49 of 121) for immunoscintigraphy (IS), 61.2% (74 of 121) for computerized tomography (CT), and 72.7% (88 of 121) for IS and CT combined. The positive predictive value was 83.1% (49 of 59) for IS and 88.1% (74 of 84) for CT. Sensitivity of IS was 100% (23 of 23) for primary tumors, 17.7% (11 of 62) for hepatic metastases, and 41.7% (15 of 36) for extrahepatic abdominal metastases. Of the 50 hepatic lesions evaluated by single-proton emission computerized tomography, 11 were localized by IS. Only one was visualized by planar scintigraphy. Sensitivity of CT was 87% (20 of 23) for primary tumors, 67.7% (42 of 62) for hepatic metastases, and 33.3% (12 of 36) for extrahepatic abdominal metastases. Sensitivity of IS combined with CT was 72.6% (45 of 62) for hepatic and 55.6% (20 of 36) for extrahepatic abdominal metastases. Of 24 malignant lesions measured by the pathologist to be less than 3.0 cm (maximum dimension), 7 (29.2%) were detected by IS and 3 (12.5%) by CT. Of 28 malignant lesions greater than 3.0 cm, 23 (82.1%) were detected by IS and 24 (85.7%) by CT. Overall, IS and CT complemented each other in presurgical staging of colorectal carcinoma. IS was of greater value for identification of extrahepatic and small metastases. CT was more effective for identification of hepatic metastases.