Positron emission tomography in the evaluation of stage III and IV head and neck cancer

BACKGROUND

Detection of metastatic disease in head and neck cancer patients is critical to preoperative planning, because patients with distant metastasis will not benefit from surgical therapy. Conventional radiographic modalities, such as CT and MR, give excellent anatomic detail but poorly identify unenlarged lymph nodes harboring metastatic disease.

OBJECTIVE

A pilot study was conducted to evaluate the usefulness of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) detection of metastatic disease in patients with advanced-stage head and neck cancer.

METHODS

Total body FDG-PET imaging was performed in a prospective manner on 12 consecutive patients with a new diagnosis of stage III or IV mucosal squamous cell carcinoma of the head and neck. Chest CT was also performed on all 12 patients. Patients found to have metastatic disease on either CT or PET imaging underwent procedures to obtain histopathologic confirmation of disease.

RESULTS

Three patients (25%) had FDG-PET scans demonstrating metastatic disease. Two of these patients had no evidence of disease on chest radiograph or chest CT but were noted to have positive FDG-PET imaging within the mediastinal lymphatics. Mediastinoscopy was performed confirming metastatic disease in these patients. The third patient had a peripheral lung lesion detected on chest radiograph, CT, and FDG-PET. This nodule was diagnosed by CT-guided biopsy as squamous cell carcinoma.

CONCLUSION

FDG-PET scanning detected mediastinal disease in two patients (17%) with advanced-stage head and neck squamous cell carcinoma that was not identified with conventional imaging techniques. PET imaging seems to have significant potential in the detection of occult metastatic disease, particularly in the mediastinal lymphatics.

High-dose localized radiation therapy for treatment of hepatic malignant tumors: CT findings and their relation to radiation hepatitis

OBJECTIVE

High-dose radiation therapy of the liver performed using overlapping portals defined by a three-dimensional treatment-planning system (conformal radiation therapy) is a new method of treating hepatic tumors. This study was performed to delineate the differences in the CT appearances of the liver after therapy compared with other methods of radiotherapy and to correlate imaging findings to clinical findings of radiation hepatitis.

MATERIALS AND METHODS

Contrast-enhanced CT scans were obtained at 8- to 12-week intervals on 31 consecutive patients with primary or metastatic hepatic malignant tumors. All had undergone high-dose conformal radiation therapy and injection of fluorodeoxyuridine into the hepatic artery as part of the treatment for unresectable hepatic neoplasms. Tumor size, location, presence of changes within the target volume after therapy, presence of atrophy of the treated segments or hypertrophy of the untreated segments, ascites, and any changes in adjacent organs seen on serial CT scans obtained before and after treatment were recorded. Clinical records were reviewed for evidence of radiation hepatitis (nonmalignant ascites evident on physical examination and a twofold elevation of alkaline phosphatase in the anicteric patient).

RESULTS

In 23 (74%) of the 31 patients, follow-up CT studies after treatment showed a low-attenuation area adjacent to the hepatic tumor in the target volume. In two patients with fatty infiltration of the liver, CT showed relative increased density in the treatment portal. A sharp, straight interface was rarely seen at the treatment margin. Maximal effect was seen 2-3 months after completion of therapy and persisted for up to 3 months. Atrophy in the treated segment or lobe was seen in four patients, hypertrophy of the untreated liver was seen in four patients, and both effects were seen in seven patients. Extrahepatic effects included segmental right renal atrophy in three patients and duodenal wall thickening in two patients. Only two patients (6%) in this series had clinical evidence of radiation hepatitis.

CONCLUSION

High-dose localized radiotherapy of the liver results in reversible hypodense regions in the liver parenchyma within the target volume that do not have a sharp interface delineating the radiation portal. This appearance should not be confused with tumor progression or irreversible liver injury. The changes evident on CT scans after therapy are not predictive of radiation hepatitis.

CT diagnosis of splenic vein occlusion: imaging features, etiology and clinical manifestations

BACKGROUND

Previous reports have described the computed tomographic (CT) appearance of collateral veins following splenic vein occlusion (SVO). This retrospective study was performed to determine the etiology, clinical manifestations, and accuracy of CT diagnosis in patients with this entity.

METHODS

A computer search of radiology reports for a 1-year period found 52 patients with SVO diagnosed by absence of visualization of the splenic vein accompanied by the formation of the expected perigastric collateral veins. Clinical data were reviewed for sequela of SVO and clinical impact of the diagnosis.

RESULTS

In 12 cases, other studies confirmed the CT diagnosis of SVO. In no case was the CT diagnosis proved to be incorrect by other imaging studies. Angiographic records found five additional cases with SVO not diagnosed by CT, but two of five had convincing CT evidence of SVO noted upon reevaluation by the authors. Review of clinical data showed heme-positive stool in six, of which three had significant gastrointestinal hemorrhage. Splenic infarction occurred in two cases.

CONCLUSIONS

Our data indicate that SVO is more common than previously suspected and usually remains clinically silent, but CT appears to be highly specific and fairly sensitive for its diagnosis.

Isolated portacaval adenopathy in Hodgkin lymphoma. CT and US findings

We report a case of isolated portacaval adenopathy as the initial presenting feature in a patient with Hodgkin lymphoma. The differential diagnosis of masses located in the portacaval space is discussed and signs useful to localized tumors to this space are described.

CT of mullerian adenosarcoma arising in endometriosis

Mullerian adenosarcoma is a rare tumor that usually arises in the uterus. Occasional cases arising in endometrial implants have been reported. We report the computed tomography (CT) findings of histologically proven mullerian adenosarcoma arising in perirectal endometriosis in a 46-year-old woman.

Hepatic parenchymal changes after intraarterial Y-90 therapy: CT findings

The serial contrast material-enhanced computed tomographic scans of 23 patients treated with intraarterial yttrium-90 microspheres as therapy for hepatic metastatic disease were reviewed for evidence of parenchymal changes in the liver in areas not involved with tumor. Irregular low-attenuation geographic areas that developed in the hepatic parenchyma after therapy were graded as mild, moderate, or severe and were evident in 12 of 23 patients. In nine cases of mild to moderate changes in the hepatic parenchyma, the abnormality was either focal or asymmetric. In all three patients receiving the highest dose (15,000 cGy), severe diffuse parenchymal changes were seen in all hepatic segments. In the remaining 11 patients, no parenchymal changes were seen. The most pronounced changes were seen at 8 weeks after therapy and were partially or completely reversible at 16-24 weeks. All patients had minimal or no change in liver function and no clinical sequelae attributable to liver injury.

Comparisons of dynamic infusion and delayed computed tomography, intraoperative ultrasound, and palpation in the diagnosis of liver metastases

The purpose of this study was to determine whether delayed computed tomography (DCT) of the liver would more accurately detect hepatic malignancy when compared with bolus contrast-enhanced dynamic computed tomography (BCDCT). Fifty-one patients who required operation for intra-abdominal malignancy (92% with colorectal cancers) underwent preoperative BCDCT followed by DCT. At operation, palpation and intraoperative ultrasound (IOUS) examination of the liver were performed for localization and biopsy of tumor nodules. The standard for diagnosis was defined for this study as the combined results of IOUS, palpation, and biopsy. The sensitivities of BCDCT and DCT for hepatic metastases were 50% and 54%, respectively, with a corresponding specificity of 72% for each. DCT demonstrated no significant improvement over BCDCT in the detection of individual hepatic lesions. The sensitivity of palpation for the detection of metastases was 82%, equal to that of IOUS. Both palpation and IOUS were significantly superior to BCDCT or DCT in excluding false-positive and false-negative results (p < 0.001). IOUS failed to identify surface lesions less than 1.0 cm in diameter (sensitivity: 40%). Conversely, palpation was limited in the detection of subsurface tumors less than 1.0 cm in diameter (sensitivity: 33%). Combined IOUS and palpation were significantly more accurate in the detection of hepatic metastases than any single modality that was evaluated (p < 0.001).

Inflammatory myofibrohistiocytic proliferation presenting as giant gastric pseudotumor

A 5-year-old boy presented with refractory microcytic anemia, growth failure, and markedly elevated sedimentation rate. Computed tomographic (CT) and upper gastrointestinal study disclosed an ulcerated 9-cm large gastric mass, which proved to be an inflammatory myofibrohistiocytic proliferation (IMP). The characteristic clinical and radiologic features of this rare entity are herein reviewed.

Complications of continuous ambulatory peritoneal dialysis: evaluation with CT peritoneography

OBJECTIVE

Patients on continuous ambulatory peritoneal dialysis are frequently referred for radiologic evaluation of complications related to the dialysis. We studied the value of CT peritoneography in evaluating these complications. CT peritoneography is a technique in which CT scans are obtained after dialysis fluid containing iodinated contrast material is infused into the peritoneal cavity through the dialysis catheter.

MATERIALS AND METHODS

Sixty consecutive CT studies performed on 48 patients during a 5-year period were retrospectively analyzed. In each case (with two exceptions), the patient had clinical findings suggesting a complication related to peritoneal dialysis. Each study was reviewed for evidence of dialysate leaks, hernias, unopacified fluid collections, and peritoneal adhesions. The patients' medical records also were reviewed to determine the resulting therapy and outcome.

RESULTS

Twenty-nine dialysate leaks were detected on 25 examinations: 15 were along the catheter tunnel, 10 were at the site of a previous surgical incision, two were at a previous catheter site, and two were from an undetermined site (catheter tunnel suspected in both cases). Loculated, unopacified peritoneal fluid collections were present on seven examinations. Adhesions limiting dialysate distribution were shown on five examinations. Five abdominal wall hernias and two inguinal hernias were detected. Overall, at least one abnormality related to continuous ambulatory peritoneal dialysis was shown on 40 (67%) of 60 studies. In 29 (73%) of these cases, clinical management was changed.

CONCLUSION

CT peritoneography is useful for evaluating complications commonly encountered in patients on continuous ambulatory peritoneal dialysis.

CT of portal venous occlusion

Thrombosis of a portion of the portal venous system can be directly imaged by contrast-enhanced CT as a low-attenuation lesion within the involved portal venous segment with or without expansion of the vessel or enhancement at the margin of the thrombus. Collateral venous pathways are often evident, which provide supporting evidence of the occlusion. Alterations in portal venous blood flow lead to metabolic disturbances in the liver and to abnormalities in parenchymal enhancement during dynamic CT scanning, and these changes are manifested as abnormalities in hepatic parenchymal density. The detection of portal venous thrombosis or occlusion, collateral veins, or abnormal liver enhancement should initiate a search for the diseases that cause these abnormalities.

Renal dysfunction in hepatic disease: early identification with renal duplex Doppler US in patients who undergo liver transplantation

To improve early detection of renal dysfunction in patients who undergo liver transplantation, a prospective study was performed with intrarenal duplex Doppler sonography before and after liver transplantation in 42 patients. The duplex Doppler findings were compared with multiple clinical and laboratory findings; patients were grouped on the basis of preoperative renal resistive index (RI) and serum creatinine level. The mean initial renal RI was elevated (.73 +/- .07 [standard deviation]); after transplantation, it was lower (.60 +/- .06) (P less than .001). Thirty-six patients had a normal serum creatinine level at the preoperative Doppler examination. Patients with an elevated renal RI (n = 19) had a greater chance of subsequent renal dysfunction (P less than .001), hemodialysis (P less than .01), longer stays in the intensive care unit (P less than .05), and longer hospital stays after surgery (P less than .05) than those with a normal renal RI (n = 17). In 34 patients the RI fell 10% or more after surgery and none died, whereas five of eight patients (62%) whose RI fell less than 10% died. Doppler analysis enabled identification of patients without azotemia whose course of disease before and after surgery was similar to that of patients with clinically recognized renal disease.

Ultrasonography of liver. Technique and focal and diffuse disease

Because of its widespread use and availability, ultrasonography is frequently the first test used to assess patients with focal or diffuse hepatic disease. While ultrasonographic features of hepatic lesions often do not allow for a specific diagnosis, this article demonstrates typical ultrasonographic features of commonly encountered disease entities as an aid to differential diagnosis. Recent advances, including Doppler and intraoperative ultrasonography also are discussed.

CT-angiographic correlation of collateral venous pathways in isolated splenic vein occlusion: new observations

The computed tomographic (CT) findings in 18 patients with angiographically proved, isolated splenic vein occlusion (SVO) were retrospectively analyzed. The distribution of venous collateral vessels and the frequency of their occurrence in these patients were then compared with CT findings in 17 patients with proved portal hypertension and normal CT findings in 20 patients. Short gastric and coronary collateral vessels were seen in 61% and 83%, respectively, of patients with SVO and in 71% each in patients with portal hypertension. However, a large gastroepiploic vein was seen only in patients with SVO (11 of 18 patients [61%]). Recanalization of umbilical/paraumbilical veins was seen only in patients with portal hypertension (seven of 17 patients [41%]). Results suggest that collateral vessels in SVO often have a characteristic and distinctive appearance on abdominal CT scans.

Advances in pelvic ultrasound: endovaginal scanning for ectopic gestation and graded compression sonography for appendicitis

Endovaginal sonography and graded compression sonography for appendicitis are two recent, significant advances in the imaging evaluation of the pelvis. Endovaginal sonography is performed by placing a dedicated high-frequency ultrasound probe within the vagina to evaluate the uterus and adnexa. Much early research with this technique has focused on the evaluation of early pregnancy, where changes related to intrauterine and ectopic gestation are evident at least one week earlier when compared with routine transabdominal ultrasound. Graded compression sonography for appendicitis is an ultrasound search for the inflamed, nonruptured appendix performed by compressing the right lower quadrant with a linear array transducer. Both techniques are fast, safe, and inexpensive evaluations that can be used to evaluate patients with nonspecific clinical findings and are particularly helpful in women of childbearing age.

Septic thrombosis of the portal vein: CT and clinical observations

The CT and clinical findings were reviewed in seven patients with septic thrombosis of the portal vein (STPV). Of the seven patients, five had associated pyogenic liver abscesses. Five of seven patients presented de novo with STPV without a clinically obvious extrahepatic source of intraabdominal infection. All seven patients were successfully managed nonsurgically with intravenous antibiotics and in two patients percutaneous drainage of hepatic abscesses. Serial follow-up examinations in five patients demonstrated complete resolution of portal venous thrombus in three patients and progression to cavernous transformation in two. When diagnosed early by CT or sonography, STVP may have a more benign clinical course following appropriate antibiotic therapy.

Acquired malposition of the colon and gallbladder in patients with cirrhosis: CT findings and clinical implications

Topographic relationships among the gallbladder, liver, hepatic flexure of the colon, right hemidiaphragm, and anterolateral peritoneal reflection were evaluated with computed tomography in 75 patients with biopsy-proved cirrhosis and in 200 control subjects to determine the effect of cirrhotic liver morphology on the anatomy of the right upper quadrant of the abdomen. Interposition of the colon between the liver and anterolateral abdominal wall and/or diaphragm was seen in 18 of the 75 (24%) cirrhotic patients and in six of the 200 (3%) control subjects. There was a strong correlation among gallbladder malposition, colonic interposition, and a ratio of transverse caudate lobe width to right lobe width (C/RL) exceeding 0.60. Patients with cirrhosis, colonic interposition, and gallbladder malposition had a mean C/RL of 0.62, compared with a mean of 0.50 for cirrhotic patients without interposition (P less than .0001). The mean C/RL for control subjects without interposition was 0.43, as compared with 0.69 for control subjects with interposition (P less than .01). These acquired malpositions of the colon and gallbladder may pose a diagnostic dilemma and increase the risk of inadvertent injury during percutaneous liver biopsy, interventional biliary tract procedures, and laparotomy.

The inability to detect kidney disease on the basis of echogenicity

With the use of new sonographic technology, we have observed that the echogenicity of kidneys is often equal to that of the liver in patients in whom there is no evidence of renal disease; this observation conflicts with the generally accepted notion that a normal kidney is always less echogenic than the liver. In order to reassess renal echogenicity as an indicator of disease, three experienced radiologists blindly reviewed the sonograms of the right kidney and liver in 153 patients. The prevalence of renal disease was 26% (40/153). Accepted sonographic criteria for abnormal renal echogenicity (kidney echogenicity greater than or equal to liver) were neither sensitive (62%) nor specific (58%) for renal disease, with a positive predictive value of 35%. Most of these inaccuracies occurred because 43 (72%) of 60 patients in whom renal echogenicity was equal to that of liver had normal renal function. If stricter criteria for abnormality were adopted (kidney echogenicity greater than liver), specificity (96%) and positive predictive value (67%) rose; however, sensitivity was only 20%. We conclude that renal echogenicity equal to the echogenicity of liver is not a good indicator of disease. Use of stricter criteria (kidney echogenicity greater than liver) provides a specific but insensitive test.

Evaluation of ectopic bone by CT

The CT appearance of ectopic bone and its maturation in 25 patients were correlated with the findings on radiographs and bone scans. Ossification progressed from an early appearance of soft-tissue density of lower attenuation than muscle to a calcific density paralleling radiographic and scintigraphic evidence of bone formation. Persistent unossified, low-density soft tissue was detected adjacent to mineralized areas of ectopic bone in 14 patients up to 16 years after neurologic injury, often with bone-scan evidence of maturity of the ectopic bone. This soft tissue most likely corresponds to immature, unossified connective tissue, which may have a potential for ossification. Detection of areas of soft-tissue density by CT and their avoidance during surgical resection of an ankylosing mass of ectopic bone may reduce intraoperative hemorrhage and postoperative ectopic bone recurrence.

Duodenal manifestations of nontropical sprue

Barium studies of the upper gastrointestinal tract and small bowel were performed in 16 adult patients with biopsy-proven nontropical sprue. Commercially available contrast media containing micropulverized barium sulfate, suspending agents, and various other additives were used. Radiographs were analyzed for the incidence and pattern of duodenal vs. small-bowel changes associated with celiac disease. Thirteen of 16 patients (81%) demonstrated abnormalities of the duodenum which ranged from focal erosions to diffusely thickened and nodular folds. A nonspecific, mild dilatation pattern was present on the small-bowel series of 11 patients (69%). The classic radiographic signs of malabsorption, such as flocculation and segmentation, however, occurred in less than 20% of cases, apparently because of the stability of new barium suspensions. The pathogenesis of duodenal changes in sprue and its diagnostic implications are emphasized.

The subcutaneous injection port: a new chest-wall artifact

A totally implanted central venous catheter with a subcutaneous injection port is now in use in patients in whom long term venous access is required. This injection port creates a new artifact that can mimic a pulmonary lesion on chest radiographs.

CT findings in ulcerative, granulomatous, and indeterminate colitis

Eight patients with ulcerative colitis, three with colitis indeterminate, and 15 patients with Crohn disease were studied by computed tomography (CT) to establish CT criteria for each disorder in hopes of providing a new diagnostic perspective useful in the radiographic evaluation of inflammatory colitis. The CT findings in ulcerative colitis included thickening of the colon wall (mean, 7.8 mm), which was characterized by inhomogeneous attenuation and a "target" appearance of the rectum, and proliferation of perirectal fat. Bowel wall thickening (mean, 13 mm) with homogeneous attenuation, fistula and abscess formation, and mesenteric abnormalities were observed in patients with Crohn colitis. Patients with colitis indeterminate showed colonic changes on CT observed in both disorders. Initial experience suggests that CT can differentiate patients with well established ulcerative and Crohn colitis.

Ischemic colitis associated with systemic lupus erythematosus

A case of colonic ischemia, infarction, and perforation secondary to systemic lupus erythematosus (SLE) is described in a 37-year-old woman. The incidence and significance of gastrointestinal complications in SLE are discussed.